James Smallcombe: There we go. Okay, so I think I finished all the introduction. So I'm just going to say thank you again for joining us. And I'm going to hand a huge daughters down
Michael Jentschel: So,
Michael Jentschel: Thank you all for
Michael Jentschel: Being on joining this talk. And thank you for giving me the occasion to speak about our activities here at the ILO. So this is going to be the outline of this talk, I hope. Can you see the laser pointer.
Michael Jentschel: Okay. So essentially, the first part, I want to speak a little bit about
Michael Jentschel: Nuclear physics and chemistry instrumentation at the research react of the aisle in the second part, which is actually the main part of this Torah.
Michael Jentschel: You will be listening. Something about this gamma rays spectrometers the crystal spectrometers I will explain it, the principle of them.
Michael Jentschel: And I will give some example experiments in which I believe they were shining really
Michael Jentschel: Nicely. And then as you might have read it from the, from the abstract on some of you might know this is this is an this spectrometers are going to be this model that will explain why.
Michael Jentschel: And I will give them a little short third section. Some out view where I believe this technology and this this expertise will migrate and might still have
Michael Jentschel: Hopefully fruitful future. So just to give you some orientation. This is Grenoble this are the French Alps, you know, the big ring is the European synchrotron and this
Michael Jentschel: Let's say this box here, this is the research reactor. It's here since quite some time over 50 years and it's dominating the new term research landscapes and develops those and all this time so
Michael Jentschel: I start with the first talk the eyeball itself is actually an International Institute mainly founded by three countries, the UK, France and Germany. So they contribute to the budget, something like 90% and then we have so called associated member countries who
Michael Jentschel: Depending on the capabilities and their budgets contribute less, but then get also only a small fraction of the meantime, so the no budget of the ILO is about 100 million euro.
Michael Jentschel: This is not our salaries, I have to take most of that goes of course and feel elements and Nicholas safety and all these things. So really an infrastructure and running such a wonderful machine.
Michael Jentschel: But it is a good budget to do good sides. And we also do have been an ongoing investment program and here out of this budget and from the associates, which is, I think it's a very
Michael Jentschel: Comfortable and pleasant situation over many years. So you can see a roughly the fraction of how much been time and users.
Michael Jentschel: Are distributed over the according nationalities and of course you can see clearly that those. We can't just the UK, France and Germany are dominating but then
Michael Jentschel: The associated members also here and you do have also sometimes user from non member countries order in the recent past. This is going to get much, much more difficult.
Michael Jentschel: Because the law is seeing some budget deficits and the assets. It's asking us to make some pressure to contribute to the if you want us to be in
Michael Jentschel: The area of research is very broad and actually most mainly dominated by neutral scattering the biology solid state physics magnetism.
Michael Jentschel: Some fundamental properties of the neutron. You see in neutral interferometer but there's also some nuclear science. Yes. You can see here by this little
Michael Jentschel: Beauty shaped nucleus. So, and I'll be talking, of course, essentially about activities in this in this field today. Good. The reactor itself. You can see a cut is a
Michael Jentschel: Two layers couple. You can see there's like an inner layer here and an outer layer in between there's an air gap of about a meter.
Michael Jentschel: The entire building is airtight so you have an under pressure. His and Casey, because the league always cleaner could come in.
Michael Jentschel: I see in the ground in the basement. You see all the infrastructure like heavy water pump cooling then here's the core of the reactor. Actually, the light. What a pool containing
Michael Jentschel: Heavy Water vessel. This is a transfer channel you see here, and then all around here. There's an experimental hole in which
Michael Jentschel: You can do experiments and you're also doing experiments on the second floor because you can extract nutrients also critically and then
Michael Jentschel: They're very slow. This so called filter called nutrients. This is going to be there should be another subject of your service is about very fancy properties of nutrients is becoming very slow.
Michael Jentschel: Very long way Venus. You can store them and bottles, as I said, is another subject matter not be talking about it. So if we zoom in to this.
Michael Jentschel: A little bit can see here the heavy water wrestle and in the center. This the fuel element. And you can see this kind of fancy fingers pointing
Michael Jentschel: tangentially to this with respect to this to the fuel element. These are so called me to pick up. So from here, the nutrients are scattered out of the light. What a moderator to what's the neutron guide to the experiments outside
Michael Jentschel: Let's assume any further can see here the fuel element itself. So it's something like a hollow aluminum cylinder in the middle, you would have some cooling water and also the control bar coming up and down and controlling deficient reaction. And then this little
Michael Jentschel: Gaps can. You can see here that we both have the fuel element which is highly enriched uranium is about eight eight and a half kilogram that we have in here and
Michael Jentschel: It's only getting really critical in a specific environments. If you would have this amount of random just standing around it will not get critical needs really the reflectivity of of its environment to make a critical reaction.
Michael Jentschel: So here's a cut of the reactor and of the neutron flux distribution to the red shows, of course, the most intense flux and then further we go away. We we lose an intensity and accuracy calculations and simulations.
Michael Jentschel: The neutral flux as radio distance and this for different spectra. So the thing we are mostly interested in
Michael Jentschel: Is the so called terminal flux of the green line here. And so you can see roughly that at a distance or 50 centimeters, where most of those fingers are picking up a neutral flaps. You can have
Michael Jentschel: A neutral Flex up to 10 to the 50 nutrients per square centimeter some seconds. So this is where and this isn't the Caesars is not Paul's. This is just continuously and this is running.
Michael Jentschel: All over reactive side which is about 50 days 24 seven. So you have a very constant neutral flux of this intensity over here.
Michael Jentschel: As a little side room up what you can see here in this plot, they're like dark crosses is our measurement points.
Michael Jentschel: And you see also align this dark green line. This is an calculation from a guy who was actually
Michael Jentschel: The leading engineer and projecting this reactor. So, this this calculation date back to the 60s beginning 70s. And what you see, then the
Michael Jentschel: light green points this are MCP simulation that this is our nowadays, state of the art in can see how amazing the precise those calculations were already 15 years ago. This is really fantastic how people could calculate it that unless the magnetic flux is already
Michael Jentschel: Okay, now let's talk a little bit about what happens to a nucleus. If it's put on a
Michael Jentschel: Neutral environment. So you can see here the neutron symbolized as a wave, and I will not lose as a potential
Michael Jentschel: And so since it's a negative potential will have some bound states in it. And of course, has also unbound states in those states they can interfere with the new term rate and we can have a capture into those bounds states and what we are left over them as an excited nucleus.
Michael Jentschel: And this the expectation that you must go summer, it could be also that, by the way, the nutrients. Just get out of this is what people use a neutron scattering. So just gets a phase shift here called juice or
Michael Jentschel: Parameters by so called scattering length, but the nutrient essentially goes off, but we are focusing on the caption reaction what happens when Newton goes into the nucleus. So
Michael Jentschel: The first thing that you should see here is the probability of making it into the nucleus can vary enormously. So I've just plotted the Newton capture cross section.
Michael Jentschel: For the good Liam isotopes. And you can see the just for those isotopes. You have already tend to defy formation of you to capture cross section.
Michael Jentschel: And also, if you look of the neutral Cups, cups a cross section as a function of energy. You can see like the virus region. So this is a so called one of the V region.
Michael Jentschel: So here the Newton capture section essentially scales was one of the velocity because the interaction time is kind of increasing that slow. I'm getting
Michael Jentschel: And that's why the probability of getting captured this higher
Michael Jentschel: And then of course we run into the resonance is that's where the Newton wave is much closer to those to the waving of those dates and you would have
Michael Jentschel: Enhanced captures, of course, these are discrete lines but there can be very dense. The typically in a term of locks the operating this region and the one of the V region.
Michael Jentschel: And so we can get very high capture rates. So essentially the target can be completely black capture all nutrients, but there are also isotopes going down to Melbourne.
Michael Jentschel: Capture cross sections, it's, it's a huge variation of direction. So one of the exciting is by mission of gamma rays. This will be the main focus of this talk. So we will be
Michael Jentschel: Talking about what, what can we do, how do we measure those gamma rays and how, what do we learn from that other ways is
Michael Jentschel: That if you put in an recording target that you could induce by the Newton capital efficient process and this helps you to produce very exotic nuclear far away from the line of stability to its Newton, which side and we also do spectroscopy of those nuclear
Michael Jentschel: Of course, we do have all other kinds of reactions which could follow up like alpha beta decay electron conversion calculator everything that is in a normal nuclear physics textbook. You can find there. So here you see a layout of the island reactor and
Michael Jentschel: It's neutral guy towards the round part here is just what I had shown before the vertical cut this is now horizontal. This is our reactor. Do you see here, what's the area of
Michael Jentschel: The experimental whole I was speaking about and then neutrons can be also guided out by total reflection to choose to give you a scale from the
Michael Jentschel: Center here to here. It's about 100 meters. You can be guided out and experiments can take place over here vertically to that there's a second guide.
Michael Jentschel: And now the question is, of course, if you want to do gamma spectroscopy. Where do you do that you could go here.
Michael Jentschel: That we have this very high influx, we would put in, try to put in targets into the wrapped into this high influx Bobby would go to and have a neutral guide. You see how it would look like. And then we have something like 10 to the 10 neutral flux. So, we lose some.
Michael Jentschel: Not some news five orders of magnitude roughly to come to come here, but both things have kind of the justification.
Michael Jentschel: Because if you think about it, even if I would put in a sample here. The closest position where I could put up an experiment would be somewhere around here in this environment. I could put a spectrometer into direct
Michael Jentschel: So I'm always at minimum seven meters distance. So this automatically sets me solving of 10 to the minus 610 to the minus five.
Michael Jentschel: While here around the neutral be mechanical very close I can get close so 10 centimeters to the target and then I will have a solid HANG OF 10 to the minus one. And so, sorry. Those two things.
Michael Jentschel: Are quite
Michael Jentschel: And using quite different options. So if you multiply this number by this flux. So you come to something like 10 to the minus attend to the nine events that you could measure the same is true over here. So,
Michael Jentschel: Here, however, you have a column A, the beam already because it's a 10 to the minus five that comes out. Susan Hall you at a distance.
Michael Jentschel: Here you have a full pie be more so. On the other hand, this
Michael Jentschel: Last solid and we would allow you to go for coincident measurements, while that one is career, it becomes so small that you wouldn't see anything anymore. So, therefore, you can see already there, like two options of doing experiments and both of them are kind of complimentary
Michael Jentschel: So we do around actually two instruments imagery follow the first principle, where the target goes into the reactor. As you can see, the one instrument is so coefficient fragments operators that we would put in
Michael Jentschel: This position here is our material right into 35 or other physical materials and then efficient fragments are emitted actually in for pie, but a few of them are emitted along this
Michael Jentschel: Record beamed up and then they see a V and be over effective induced by a magnet and condenser and this allows us to make a massive operation of division fragments and carry out then selective spectroscopy over here, or just studied efficient process itself.
Michael Jentschel: So you can see, you could think of having a detector here. The good thing about this machine is has very short delivery time efficient fragments to here. So we talked about if you microseconds only. So this allows you to make gunnery spectrometry of micro second item is
Michael Jentschel: Another instrument on which the main focus of this talk is going to be on crystal spectrometers so again we put targets into the
Michael Jentschel: Into the reactor your clothes and close possible position and then again gamma radiation is admitted and for pie and a few of them are going along this line and
Michael Jentschel: Making the fraction of those gamma rays over here. So for crystals, you can think already the fraction is a geometric process. We need this kind of culminated beam line for them. This kind of layout is this is a natural kind of setup.
Michael Jentschel: So at the neutron beam we do what most people nuclear physics people do a beam lines. The set up detector race. So this started summer 2010
Michael Jentschel: Because until they're only very few detector raised actually put around neutron beams of we
Michael Jentschel: Tested this first time by 880 percent detectors that we were borrowing from Cologne.
Michael Jentschel: And demonstrated that you can call me down a massive neutral being very narrowly to make a pencil beam and they would not get the detectors would be no scattering into detectors. You can do very clean spectroscopy by that.
Michael Jentschel: And this first show up experimenters then actually triggered a much more massive campaign in
Michael Jentschel: renting the x ray from from Danielle plus gas detectors from the New York and London bromide from the fact Kadima collaboration and doing spectroscopy efficient fragmented spectroscopy and and gamma spectroscopy around the neutron beam.
Michael Jentschel: Still, this was 100 days of being time, not everything could have been done. And this was a very successful campaign. And at the end, the island management decided to invest in our own around. We are now setting up a building up this more and more massively. So right now we own it.
Michael Jentschel: Own clovers with this and the company shields and we will be own our own London permit detector sets and we are slowly ramping up this activity and neutron beam to do more and more experiment.
Michael Jentschel: So you see, we are doing actually or so far we are doing those two configurations, like in pilot experiments, Miss high resolution spectrometers and
Michael Jentschel: Beam experiments is highly efficient detect the race. We were doing those things at the same time.
Michael Jentschel: Now in the following follow up. I will talk about the crystal spectrometers the cameras, but only there's only so therefore, the question is do you have questions so far to to what I was saying.
James Smallcombe: Say, if you want to go into that participants menu and hit the raise hand if you do have a question or I don't see any in the chat box.
James Smallcombe: I did just have one
James Smallcombe: Quick question, which was, basically, I think I should probably know more about raptors that I did.
James Smallcombe: Over the course of the 50 day cyclist and you from flux pretty constant or do that tail off towards the end of the cycle. It is. It's
Michael Jentschel: This constant isn't 5% or even less so it's it's amazing you control this automatically
James Smallcombe: Yeah, this is
Michael Jentschel: This is if you want for a nuclear physics experiment.
Michael Jentschel: He do because you do
Michael Jentschel: You don't have to worry much about monitoring or anything or it's also how to say very robust there's if you compare it to accelerate experiments you have hardly you know beam fail or anything, you just run, run, run, run, run.
Michael Jentschel: Very pleasant.
James Smallcombe: Let's see, we've got a question from Steve as gonna go ahead, Steve.
S Yates: Just, just a quick question.
S Yates: I use tangential beams, is that just to avoid the background, looking at the course or something else to be gained.
Michael Jentschel: It is exactly for that. First of all, you don't in the most nutrient means you don't want to have
Michael Jentschel: The gamma ray background.
Michael Jentschel: And for for my particular for this through going being to be don't even want to have a little nose or any material that because he would have
Michael Jentschel: The courage, he would have
Michael Jentschel: Gotten scattering. It's essentially what he said backgrounds elimination
S Yates: Okay, thank you.
Michael Jentschel: Mr. Oh, I should say. One more.
Michael Jentschel: The React is designed specifically
Michael Jentschel: To have a flux maximum outside the core. So even if you would point to the quality would have less flux
Michael Jentschel: So that's, that's
Michael Jentschel: As an additional feature of the reactor, because people knew that they need to pick up the nutrients tech actually
Michael Jentschel: All right, now let's go to the crystal spectrometers. So the first thing I don't confess that I'm not talking about Christmas Khatami's but I will talk about normal detectors. So what I call
Michael Jentschel: Absorption detector. So the principle is very similar to all of them. So, you, you want to have the gamma radiation fully absorbed in a certain volume.
Michael Jentschel: And secondly, you want to have that this volume has some quantum phenomenon. So some some data. He some quantum
Michael Jentschel: Think so in the semiconductor would be the band gap in the simulator would be an optical transitional you could have Michael color emitter so
Michael Jentschel: Running close to the transition point to superconductivity. And then it would be Cooper break up energy
Michael Jentschel: So if a gamma ray gets absorbed and as detectors. It's deposed energy creates those quanta those events decides those and the number of them and excite is proportional to the energy
Michael Jentschel: So what we want. We want to count, actually this end. So this is what we want to measure because it's proportional to gamma
Michael Jentschel: Now, everything depends. Now, since it's a statistical effect how small that is and you can see
Michael Jentschel: In an optic transition, it's it's bigger than, let's say, the band gap and germanium and that's why the resolution our resolution of what we will see is actually depending very much on on this that
Michael Jentschel: Secondly, depends whether for each gamma ray, we are capable of getting the recording number ends. If you have too many cameras at the same time.
Michael Jentschel: This counting process gets confused. The next thing is we have to get
Michael Jentschel: All those counters, you should lose any of those ends and we have to make sure that really the Gamma Ray was completely absorbed all this, put some limitation.
Michael Jentschel: To such a detector. I mean, he has many wonderful properties. It's very simple to handle it's you can put money of them. They're not very expensive to all this
Michael Jentschel: Is fine, but it does have some intrinsic limitation and the main limitation for resolution comes from the fact that this end is offended number and you have a statistical
Michael Jentschel: limitation on how good such a resolution creepy. Now, if you talk about the crystal spectrometer. The
Michael Jentschel: The other say the transfer process is different. We want to correlate now the energy year with another observable, namely the angle to be measured.
Michael Jentschel: Okay, so there's no quantization anymore involved. This is a continuous process always provided that these constant, of course, okay and agency, of course, to
Michael Jentschel: So the funny thing is that this process of this principle of measuring gamma rays is much older. As you can see that all the other detectors that you know about all the meanwhile,
Michael Jentschel: Crystal spectrometers have essentially disappeared from the, from the landscape of cameras spectroscopy completely so nobody does in real life and and so why and why it is difficult and however what you could gain. This is what we want to understand right now.
Michael Jentschel: So to do so, we have to look a little bit deeper into into this very simple integration. So what we want to do first is you want to invert and look what what is the energy resolution.
Michael Jentschel: Depending of so you could write up something like this dispersion equation say that your energy resolution is something like this expressions of a of a delta d
Michael Jentschel: Let's say a variation of a letter spacing and a variation of of of your, your angle.
Michael Jentschel: And to have it more simple. And since you will be talking about very small angles. Anyhow, we can simplify this expression that this is roughly the same as this one above here.
Michael Jentschel: Now, the first question is, how big is this data, God and to come down for a very long moment is discussion. It was a big discussion of course at the beginning and crystals crystals were really rare.
Michael Jentschel: So beginning means until the appearance of massive semiconductor production semiconductor crystal production.
Michael Jentschel: Nowadays, so what you see here, this is a lattice constant measurement of
Michael Jentschel: Our guns crystal. That's one of the six crystals. You can see here that the variation of the lattice constant over
Michael Jentschel: The full range here is less than or the order of 10 to the minus eight. So this is, this is a very small number here and either
Michael Jentschel: For the next part of the discussion ignore this contribution and we will be talking only about the contribution of data, data to the resolution. So, this
Michael Jentschel: part has actually kind of three main contribution. One is the being divergence, one would be the contribution from the diffraction process itself.
Michael Jentschel: And one is from the, from the art from the way you would be measuring the diffraction angle. Okay, so it's your accuracy of positioning the crystal and measuring design.
Michael Jentschel: So I will already say in advance the benchmark will be set by the middle processed by the fraction process. And so what we do is we look now in a mode in a deeper theory than the simple practice law and it's called dynamic to the fraction theory.
Michael Jentschel: And I don't want you to read all this year. This is later on for for record, but essentially what it tells you this, that the probability of reflecting or the fracking of crystal.
Michael Jentschel: Is a function which has an isolated term can see it here and it has
Michael Jentschel: Lorenz Ian and Bella, and this why you this parameter. Why is kind of proportionate to our measurement angles. It's a deviation from this bragging. Okay.
Michael Jentschel: Time, some other constant. Again, this is, this is not really important for the moment. So what I do. Now I will plot this function. Okay, so you can see this here and I have done that.
Michael Jentschel: For four different energies. So again, you see here, this oscillation term.
Michael Jentschel: And you see the lawrenson envelope and you see if I increase it. So first focus only on the, on the, on the pink curve. Okay. If you increase it. The big the energy, it becomes more and more narrow.
Michael Jentschel: The second thing is you see depending on the crystal orientation. I seem to have different
Michael Jentschel: Laws are different scales of it. So it's always the same Lorenz, Ian. It's always an oscillating term simply. This is different.
Michael Jentschel: Okay, so this can be understood. This is hidden in this parameter lambda zero here. This so called structure constant in it and it's responsible for it.
Michael Jentschel: So if you develop this theory and you look what's the base of this lawrenson you can come to this expression here.
Michael Jentschel: Okay and this expression we can subdivide it in two parts. One is the classic left on radius compared to the lattice constant which is something like five times 10 to the minus six.
Michael Jentschel: And that guy here is the one which is responsible for the scaling of of this Laurentian depending on on the crystal orientation itself. This can scale from let's say open five up to 25
Michael Jentschel: Okay. Now if I take that guy and divided by the bracket, because it's the contribution to the energy resolution, I come to something like one 200 times 10 to the minus six.
Michael Jentschel: What's, what's the message of this of this plot, it tells you actually that the diffraction process itself provides you the potential to PPM resolution of gamma rays. So you could, you should be able to measure an elec and mega electron will down to an electron what resolution. Okay.
Michael Jentschel: However, they were the two other terms of the gun your meter and of the beam and they got to be of the same order of magnitude of this if they're divided by by the backend.
Michael Jentschel: Now to make this number just specifically see put in one mega electrical you look how big the break analysts and the consequences. The both of them have to be in another region region.
Michael Jentschel: So you've got to measure your, your, the fraction angles to none are aging and you've got to have a beam which has a nano rating divergence
Michael Jentschel: Okay, can we do that. So first, let's talk about the angle measurement. So you can see it already from the title. This is
Michael Jentschel: The root of the way how to measure them even better than anomaly and what we use.
Michael Jentschel: Here is essentially technological development of displacement measurements. So we see here essentially a Michaelson from it. So this is the beam splitter.
Michael Jentschel: Okay, so you come in here with the beam. You send one and this direction, we send it back and the same you do downstairs, and if you rotate such an arm that the two persons, let's say are separated by distance K your angle.
Michael Jentschel: You rotate by mango you measure distance would change by data. And that's what it in the form it is detected
Michael Jentschel: Now, modern displacement. The parameter is capable of detecting 10 to the minus 10 meters. This you can have a review.
Michael Jentschel: In which you see numbers of interferometer region that this is kind of a, it's not a Otter say unique achievement of one particular interferometer, this is, this is what you can achieve.
Michael Jentschel: It is not difficult. It's not easy. You have to do certain careful things but but this visible. Now, in our case, typically this k ism is open 25 but since we have the factor for here. We really come to
Michael Jentschel: Be make it to make our seminary, the measurement. Now, how is it realized in our case. So we build up.
Michael Jentschel: Looks a little bit more complex than what you see here. And the reason is we will be measuring actually the angle of two crystals, you see one crystal would get mounted here, you see this fancy prisons.
Michael Jentschel: They sitting here on an arm, you see the two beams hitting it. And the same as going in the other one and you see a complex interferometer lay out all this is how to say bond to very low expansion glass corral mix. And this is actually technology we have
Michael Jentschel: Learned in the UK at the Institute of gravitational research in Glasgow. So what you have to have after learn, you have to know how to bond glass subjects chemicals chemistry free to
Michael Jentschel: amongst each other. And it's a technique called silicon bonding. I don't want to go very much in detail into that roughly speaking, you injected most the surface of liquids at
Michael Jentschel: To
Michael Jentschel: Two glasses you you inject well controlled amount of liquid and temporarily opening the ionic bond of those surfaces and if
Michael Jentschel: The liquid since development of the fuses into the solid they recrystallization crystallized as a as a bulk solid again we see what we did here is we just the bonding to class sheets on each other, you're testing and
Michael Jentschel: You know what it was hauling so this is 50 litres of water, no problem, and sharing it didn't.
Michael Jentschel: Didn't get detached later on they were putting it on a on a milling machine to push it away. And next week was the glass breaking was not the bond breaking. So, all, all these
Michael Jentschel: Components here our bond together by this technique. And the reason is you want to have no drift. You want a very stable regime to get to this very accurate measurement Kabila
Michael Jentschel: So if you do that and you have to put everything that vibration FISA you see all the sits in a vacant chambre on on on anti vibration system. You really achieve very good
Michael Jentschel: angular resolution and just to put this into scale to our the fraction of that yet seen before. So this is now a measurement that would take seven days. So we would stay
Michael Jentschel: Controlled by on the point here for seven days. So this will be a really controlling variable and the situation is such a device. So the message here is that angle measurement capability is something we can do today at the, this, this, this level of frequency
Michael Jentschel: Now the last problem here is now of course the beam divergence and having an honorarium Bemis is really something you don't want to have you don't make very easy. And the trouble is, I illustrated this in this little animation.
Michael Jentschel: If you have just the classical beam, let's say, and you can you can probably call him a two to 10 to the minus four radium and you would scan now with the crystal. You're over it.
Michael Jentschel: You see here this is the divergence of the beam and this is when the crystal what started the fractals. And this is the the
Michael Jentschel: Recorded intensity you would essentially have a vis which is dominated by the beam divergence and you could not distinguish those two curves.
Michael Jentschel: The first way of overcoming that is you could try to adapt your crystal to this divergence. This is actually has been proposed.
Michael Jentschel: Somewhere in the 40s by do more than push WHA YOU TAKE A band crystal and that crystal is then
Michael Jentschel: Looking like that is the factual profile would scan like that over over this divergent beam and you see the resolution substantially better
Michael Jentschel: However, when you were bending this crystal, you actually rest raining it and you were using now some some crystal imperfections of this data. Do you have a D equal 10 to the minus eight is not fully developed anymore until you do a compromise.
Michael Jentschel: So essentially if you build something like that. You can see here, this is a band crystal. This is one way or we do spectroscopy was a band crystal.
Michael Jentschel: That that's the homogeneity of this Chris Leo showing that by banding you induce some imperfections. So this is how much a BRAC Englewood deviate.
Michael Jentschel: Depending on this position on the crystal. So in the center. You have summer rather homogenous spot until
Michael Jentschel: Up to some level. This is a good geometry and it provides good resolution, but it's not the ultimate resolution. Okay. Moreover, in this geometry also
Michael Jentschel: Actually becoming sensitive to the thickness of a target because if the photon comes from here or comes from here. It's quite a different bragging. And so again, for you this
Michael Jentschel: screws up to some extent, the resolution of your, of your instruments, you will see
Michael Jentschel: Later on how good those instruments performed, but I can tell you already know. They do not perform at the ultimate resolution that the diffraction theory was predicting you
Michael Jentschel: Know, to come to the diffraction theory, you have to use a trigger. True. So you take one crystal, as you have seen already in the single flat crystal scheme.
Michael Jentschel: But you don't rocket anymore. You just put it in one given position and now it's the fraction and actually it's creating an image. Okay, so it's very narrow the fact that
Michael Jentschel: Point here and now the second crystal can rock around this cruise around this image of this on. I would rock over it.
Michael Jentschel: That's parallel, it could not yet distinguish the two points because the red sea's the red at the same time as the blues is the blue.
Michael Jentschel: But you can put a dedicated angle between the two crystals which is once given BRAC angle. And in this case, you invert actually the order of the to the
Michael Jentschel: Expectation function of the second crystal. And now you're becoming capable of resolving in a way. Now the divergence of that beam here.
Michael Jentschel: Okay, have been between the two crews is defined by the first one. So it's actually he's acting like a divergence
Michael Jentschel: Okay. The trouble is you don't get much through it here and and to compensate you need to use not a massive target. Okay.
Michael Jentschel: Advantages the divergence. He does not depend on the target geometry as it did for the band crystal spectrometer, it's this guy filters in terms of. I know that I registered
Michael Jentschel: As as those those very narrow diffraction curves are showing and you see the beam here is very narrow and in divergence. And so this
Michael Jentschel: Second crystal. And now I have some substantial intensity and we will, we should get actually automatically resolution. Now let's compare the resolution that you can achieve. So what you see here is the classical composition of Germanium detector to London Brahma.
Michael Jentschel: Simulator. So this is all things that you know from from your daily laboratory experiments, probably, and now we should compare how the band crystals would would
Michael Jentschel: Show up over here you can see already. They are substantially better than the germanium crystals. So the pink line here is the germanium detect is a Germanium detector. Okay.
Michael Jentschel: And then this is from the spectrum, taken from the same target name 188 re renewed and you can see a German detectors NEVER ABLE of resolving such Dublin's
Michael Jentschel: More of a Jimmy Dean detective will not be capable of detecting such difference in such a different intensity. So the dynamic range here.
Michael Jentschel: is fantastic because you always go back to the same baseline, you don't have any intrinsic competent effects or anything like that. So the dynamic range of of a crystal spectrometers tend to be six.
Michael Jentschel: Now if you go to the double flat crystal, the one where you have or should have theoretical resolution. It's even better. So you see here and want to be roughly at one mega electron more measured, we have something like for electro mode resolution. Okay, so this is this is the way to get
Michael Jentschel: To get to the theoretical best resolution, the double flat crystal spectrometer. Here you see again an overview and how
Michael Jentschel: Resolutions as a function of energies performing. So this would be typically a Germanium detector. Now you see here.
Michael Jentschel: The band crystal spectrometers and you see the double flat crystal spectrometer. So the double flood crystal spectrometer remind you that the
Michael Jentschel: Food is have maximum of this Laurentian was scaling with one of he and Brackla the bragging was also scaling with one away. That's why, at the end, we get a constant. The constant resolution.
Michael Jentschel: For the bankers who are using some imperfection, the one over a scaling is lost. And that's why we see an energy dependence and you can see that starting from some energy of here something slightly above one and maybe a classical germanium detective become super and energy resolution.
Michael Jentschel: Good. Now, how do we realize that, oh why if those crystal spectrometers actually so good. Not everybody's using them. And then here's the answer. So we actually
Michael Jentschel: Have to look at a very intense source and it's placed here, as I said, close to the reactor. You see it symbolized here.
Michael Jentschel: And so gamma rays would be calling made it out to form a been to spectrometers and we have actually run two of them. One
Michael Jentschel: Which I would call this a precision machine and the other ones multi purpose in which you can easily change crystals.
Michael Jentschel: And so the intensity coming or the intensity would be counting at the end and the detector here would be given by this kind of formal
Michael Jentschel: So the first thing is an idea and I not which is the intensity of the governor is admitted and the target.
Michael Jentschel: The next factor is the solid no to make it here. So actually, to form such a beam by the consummation. The next factor is
Michael Jentschel: How much of that radiation is actually accepted for the fraction. So this is the this your acceptance. This of your the fraction divided by the divergence of the beam.
Michael Jentschel: And the last one is the reflectivity. So the probability to reflect and this quantities. You see them here. So the solid angle to to make a beam is about 10 to the minus six.
Michael Jentschel: This, this much here is in a flat crystal case 10 to the minus three and a band one we've adapting it to the version. So it's one
Michael Jentschel: And then the reflectivity. So it's typically tend to the minus one for one crystal. So since we have to its credit here.
Michael Jentschel: So at the end of the day, you see that the total throughput of such a crystal spectrometer. If you run it an ideal case is 10 to the minus 11 so that's a miserable luminosity, if you want. So we need to produce 10 to the 11 photons to get one through
Michael Jentschel: The band crystal. One is somewhat better because you're one only and you accept the divergent. However, we don't make it to the full resolution.
Michael Jentschel: Now you need to be compensated. And you can come in and by using massive targets. So in the case of the flat crystals, we have to put grams of target into the into the reactor
Michael Jentschel: And then you have something the best case tend to the 16 gamma emission rate if the target is capturing less. It's about 10 to 15 capture
Michael Jentschel: The total admission rate. And then, of course, everything depends on the branching inside the particular nucleus, depending which transition, you want to measure.
Michael Jentschel: So that's how it looks like. So this is when the target changes that this little device which drives in was still not in the reactor before it was mounted you to take some pictures. Here's a target 10 minutes of we're looking. We're looking into a hollow
Michael Jentschel: Let's say two. So, we have no background from YouTube itself. You only see this targets. This is how they look like
Michael Jentschel: And this is seeing the same type of change from above. So we can load up to three different targets and they are actually sitting in a mechanism allowing an alignment with respect to the to this crystal spectrometer axis and alignment from outside agencies, it's motorized
Michael Jentschel: Alright, so now I would come to the experiments and
Michael Jentschel: Question is, does anybody have questions to me before I start speaking about experiments again.
James Smallcombe: So we've already got one Steve Yates against right off the bat. Please go ahead. Steve.
S Yates: Yeah, Michael, you didn't say anything about thermal stability.
Michael Jentschel: Thomas, the ability of
S Yates: Of the van crystal are the questions.
Michael Jentschel: Of the crystals. So
Michael Jentschel: I don't know what it brought here. Meanwhile, we are at Millie Calvin per day of the entire the wise, so we have very little drift. So you can forget about it. To determine expansion of the crystal which is the biggest
Michael Jentschel: Thermal expansion.
Michael Jentschel: In the device is 10 to the minus six.
Michael Jentschel: Times and melted Milica when you attend to the minus nine.
Michael Jentschel: So the Quranic we are using. There are
Michael Jentschel: 10 to the minus eight thermal expansion. There are big, big objects. Okay. But as I said, the result of this last efforts for GM six is that you can sit for days on one on one line and doesn't doesn't move.
Michael Jentschel: It was not the case in the past. I know you know you follow the story, since many years. So it wasn't the case in the past and the past spectrometers that made out of steel.
Michael Jentschel: And then slowly upgraded to more noble less extending materials developer created an atmosphere.
Michael Jentschel: Which is a big problem atmosphere because it's having moisture pressure. So the index of reflection might change. So this was the problem of the past. But in principle to to to nowadays standards and I wanted to actually to refer me to what we would do now. Okay.
Michael Jentschel: We
Michael Jentschel: We can be incredibly stable.
James Smallcombe: OK, I see built at least unmuted himself. Do you have a
William Gelletly: Question bill.
William Gelletly: Is it what is a comment. You said you made a comparison with the experiments that accelerators and how stable the reacted is etc. Of course, if you have a target near the core and
William Gelletly: You're sitting in this sort of flux, then of course you buttoning up the target all the time. And so you do have to worry about that.
Michael Jentschel: Yes, this is true of course, putting a target. There is, in any case, a delicate operation. You can put any target their first of all, you must only
Michael Jentschel: Target standing certain terminal stress and constraints, but when I was referring to the stability. I was actually having more in mind doing experiments at the neutron beam. Okay.
Michael Jentschel: And
Michael Jentschel: At the neutron beam. You're becoming very much more comparable to the accelerator because it's their be putting detector ray
Michael Jentschel: And it's devil you put a target and the advantages that the neutron doesn't hurt the target.
Michael Jentschel: Okay, it's a very gentle excited. It comes with medical we have military trauma thermal energy and it doesn't heat up the target that very
Michael Jentschel: very peaceful and now if the beam is stable and it's stable of days. This is a very pleasant way of doing experiments. It's obviously you can't actually muscle you can miss a beam, it's, it's always there.
Michael Jentschel: So this is, this is what I was more referring so you can burn a target by neutral, but inside the reactor user definitely right inside the react. It's much more complicated. Okay.
James Smallcombe: Okay, there are no more hands on any questions in the chat box. So I think we can move on to the last section.
Michael Jentschel: So now I would like to talk about experiments. So the first one I want to impress you.
Michael Jentschel: I don't want to go the physics, but I just it's a pure it's impressive what you can resolve as a bankruptcy spectrometer. So this is 188 reunion and
Michael Jentschel: This is a measurement taking okay in singles, I have to admit at the neutron beam.
Michael Jentschel: But if you measure certain fraction of the crystal spectrometer, you would see this. Okay, so this is only just a reminder, this is only 150 kilo electron mode and you see already more than 200 lines here. Okay.
Michael Jentschel: If you scan further and even higher energy. You see many, many transitions. So, and and so
Michael Jentschel: If you, if you have doubts and doublets or if you have doubts and what you're getting on for
Michael Jentschel: On a, let's say on a detector a measurement. That is a very good way of doing complimentary measurements. Even now, in the past, this kind of measurements have been used to build up complete level scheme. So this was done purely by
Michael Jentschel: Believing to know those energies very accurately and looking for energy combinations, who would make it up to a level scheme so Biarritz algorithm, if you want.
Michael Jentschel: This is to some extent, the same thing as a time coincidence but an energy coincidence, if you want.
Michael Jentschel: However, it's much more fragile than a time coincidence. And so some of those level schemes. If you look now into into them visit detector Ray, we discovered that they're actually missing quite some stuff or the wrong.
Michael Jentschel: So it's, it was the best that people could do, let's say, probably in the 70s, 80s with those machines to build complete level schemes. But now, actually the best you can do is, is using a detector Ray at the neutron beam and if you have doubts look with a
Michael Jentschel: Curve Kristen spectrometer in a particular region to make sure it's not the WW that you're getting them.
Michael Jentschel: Now,
Michael Jentschel: The next class of experiments, I will be speaking about they essentially profit from one property of a flat Christmas spectrometer.
Michael Jentschel: Which is the resolution, moreover, not only the resolution that the test, but the capability of being able to measure its own response function.
Michael Jentschel: So it turns out if you have those two crystals in a parallel mode and Europe that guy around it. So you. That's where I said, you don't have an energy resolution, but what you measure here is actually
Michael Jentschel: It's response function, because the answer should should have been a delta function breaks low on the fraction theory. This red line, but you get something slightly different. So you see this blue thing.
Michael Jentschel: But if you go in this this person in this energy sensitive mode by turning back to given BRAC angle you see a certain broadening with respect to this response function. And when people were first measuring actually in the in the 80s.
Michael Jentschel: First transitions with this very high resolution or debate quite surprised to see such line. So this is from one of the first publication.
Michael Jentschel: In 88 and I think somewhere 8687 they must have discovered this effect and it didn't really understand what it was, until
Michael Jentschel: Hans burner and his collaborators figured out that this is actually physics. And it's a very nice physics, if you want. So if you look at a two step one.
Michael Jentschel: To step transition of so let's say gamma cascade of two steps. So the first gamma ray is giving a recoil.
Michael Jentschel: To the nucleus. And if the second gamma ray is admitted to you can see to him fly to take some time on slowing down again. Then this second gamma ray will be Dr. Brody in it and you can resolve that you see here.
Michael Jentschel: This is about the time scale. It needs to slow down. So this is kinda like the atomic collision cascade here that you have
Michael Jentschel: You see here that the recall velocity is given by the energy of those first gunnery divided by the mass of the nucleus.
Michael Jentschel: And then until you reach some terminal equilibrium. And so this even, even the trauma broadening can be resolved as you see here. Okay, so this
Michael Jentschel: Final with since it doesn't depend on any initial start moment this is fine. This is it kind of what the limits you measuring very long life times. But you do have a tech D.
Michael Jentschel: Which is capable of measuring nucleus, the lifetimes. Some of the range from very short, let's say, a few femtoseconds up to the very few that you want to people seconds okay and this
Michael Jentschel: Technique was called gallery and use during broadening technique and has been used quite severely. So what I'm showing you now. Like if two or three examples of the history. And I think one of the most famous
Michael Jentschel: Again, very early 90s of of the group of fans Bernanke's the same collaboration, or very similar collaboration was demonstration of the first evidence of the two phantom
Michael Jentschel: Vibration and the nucleus and hundred 68 Arabian. And so what they did is essentially they measured the lifetimes of those two states and
Michael Jentschel: Calculate be two values and compared it to the beef to have the grounds that transition of this band and showing that is a very strong coupling and that would be something like the two phone
Michael Jentschel: Vibration on top of have a single phone on vibrate vibration and in this this contribution made it up to the Encyclopedia Britannica. So, and
Michael Jentschel: clearly showed that this technique was shining a very nicely because actually, you do have at that time and still you do have not too many techniques capable of measuring nuclear stayed lifetimes in this in this
Michael Jentschel: Time to second region, a few hundred 20 seconds. And that's, that's why made very successful way and other one later ID in the 2000s. When I was at the law.
Michael Jentschel: Was a test whether teeter regional symmetry would be existing. This was predicted by group of do deck in class bow and in principle, they wanted to know whether we could
Michael Jentschel: Actually they wanted us to prove it to some extent. And so the fingerprint, the debate defining in those papers for such as such as for the existence. Such a cemetery.
Michael Jentschel: Would be a negative negative parody band within vanishing interbank transition strikes. Okay, so you would not see
Michael Jentschel: Any interbank transitions anymore than low, you would go into in this band here.
Michael Jentschel: And so what we were doing. Now, we were trying to use the a combined effort of our crystals crystals spectrometer to see whether that is true, because actually developing themselves with detector raise and D. They couldn't find any, any of those interventions.
Michael Jentschel: So the main question is actually is this
Michael Jentschel: A teacher. He to band or is it not to the band as the grounds Defense Advanced the band is known to be optimal.
Michael Jentschel: So the first thing we did is we were looking does this transition exist. And of course, since the band crystal spectrometers do have such an outstanding dynamic
Michael Jentschel: Range, you look for that. And we actually found it to be found a transition here, which was right at the good energy. It was nine Sigma out of
Michael Jentschel: Of the of the normal background. So now, since he cannot put any coincidence with our solid angles. This is impossible.
Michael Jentschel: wasn't clear whether this is actually the right energy or how would we demonstrate that this is the right one. So what we did. Now, we actually measured
Michael Jentschel: Oh, by the way, I forgot to say that this one is 10 to the minus six of the strongest transition in 56 good leaning. So what we did now is we measured the energy
Michael Jentschel: Of those to transition and by calculating the difference, you could actually say visit a few electron volts, that this must be the right transition. So this is again something like an m and n g
Michael Jentschel: Community America the rich scheme but done this time this thing was understanding the double crystal spectrometers providing William electron more resolution and so the ambiguity was very little that that we would sit on the right transition
Michael Jentschel: The next of us we were measuring how strong this guy was coupling to deductible band by measuring the lifetime and calculating the branching ratio.
Michael Jentschel: And so we got this lifetime measurement and we could show again that this branching ratio of deployment of
Michael Jentschel: Was quite comparable to the grounds that band. And so at the end of the day can see here. Those two are
Michael Jentschel: quite comparable at the end of the day, the conclusion was that this is probably an octopus information does that
Michael Jentschel: It was very disappointing for this group and they extended the theory, following up that but it was showing how powerful the combination of of legacy of those two spectrometers can be if it's putting in the right place.
Michael Jentschel: Now the last experiment. The last lifetime experiment which was done with those spectrometers before the commissioning was done. And I'm six was actually looking for
Michael Jentschel: Mix symmetry state or optimal mix symmetry states and hundred 44 neodymium, so this is published in 2019 or too long ago and actually a verb of Makkah shakin and Paisley and media tour of in Darmstadt
Michael Jentschel: In and again was very nice combination of a lifetime measurement, but this time with a neutron be measurement baby did coincidence. So we could show that actually those two transitions here very coincidental that this band really couples to this one, which was impossible to
Michael Jentschel: To see elsewhere because you have
Michael Jentschel: Another one which is very close and energy.
Michael Jentschel: And moral is the lifetime measurement. He could calculate the branching ratio and showing that this is a multiple mix symmetry state.
Michael Jentschel: Actually, we didn't measure this, this transition over to this was the last lifetime measurement done this gun spectrometers before
Michael Jentschel: The Commission me
Michael Jentschel: Another class of measurement, I would like to show here is measurements, where we actually
Michael Jentschel: Referred to a capability of absolute energy measurement and if you want this, this
Michael Jentschel: Type of measurement was the main motivation. Historically, to build the double crystal crystal spectrometers
Michael Jentschel: This was a technique induce introduced to it by by dentist and the purpose was to measure fundamental constants
Michael Jentschel: So what it is they're relying on before we were talking only about the base of those curves. But if you look at this
Michael Jentschel: Scheme here again, actually the main difference is it to be. Take one crystal which was parallel and the parallel to be measured by the presence of this curve.
Michael Jentschel: And then we rock only one truth by a given amount by Val determine demand to see a reflex of the same
Michael Jentschel: Energy again. So there is a dedicated angle between those that we measure of one crystal. So if you know the letter spacing of this crystal, we actually measure this angle, we can use an absolute terms this energy
Michael Jentschel: Why would we do that well because a neutron capture reaction actually is a very specific or very fancy erection. So you you have at the beginning of this direction only particles and items.
Michael Jentschel: At very low tumble energies and you end up after the capture by additional gamma rays of
Michael Jentschel: 10 to the six electron volts. So typically tend to discern a little more to the intrinsic energy uncertainty of this reaction is very low. It's 10 to the minus nine.
Michael Jentschel: Again, I would say it's something you don't see necessarily at an accelerated. This is very specific to the neutral capture reaction i would i would love if somebody comes and shows me
Michael Jentschel: Another reaction this this intrinsic energy. And certainly, because that's what helped me really a lot. I have nothing in my mind.
Michael Jentschel: So now what what we have want to do is we want to write this equation in terms of masters at the end of is a neutral mass
Michael Jentschel: You write down your mass of this Nicholas here. You're right. The mass of the newly formed isotopes.
Michael Jentschel: And rewrite the energy time secrets. So to make make the masses. So all this is a must balance equation, reflecting the neutron capture reaction.
Michael Jentschel: So those muscles, you actually can measure in planning trips. Okay, very accurately. So if we do measure this guy's we actually get the neutral mass very accurately.
Michael Jentschel: What we see you for that are two things. The first thing is we assume that the mass of the free new term is the same as it is the nucleus is bound in the nucleus.
Michael Jentschel: And secondly, with the assumed the validity of people in the script. Now you might ask yourself, why, why does the guy speak about those things, but have a mind via trying to make very accurate very precise.
Michael Jentschel: Measurements here. So on the level of position or a high level position, you have to ask the validity of most any any principle migration at the epic physics. Okay.
Michael Jentschel: So what I do now in the next step I just take this expression transfer this to relative atomic units because, strictly speaking, that's what they measure in a
Michael Jentschel: In a pending trippy compare an atomic mass to the mass of 12 carbon. So it's a relative atomic mass. This forces me to introduce the atomic mass units, which again reflects itself as this constant. However, this concept. We know very accurately from other measurements in
Michael Jentschel: Atomic Physics there at the end of the day, we have actually the potential to measure the neutral must very, very accurately can see
Michael Jentschel: Now this was done. And actually we did this by measuring the binding energy of hydrogens of determine binding energy. And so you can see like a history of those measurements and this is if you want
Michael Jentschel: The first step done in 1999 here. The first measurement was done. And then we also repeated measurement of his other atomic combinations. He has a likes. We did the soft and the silicon
Michael Jentschel: And at the end of the day, we got like three numbers and they all agree, Melissa region. Now, first of all, this measurement today is still what you would see if you look in
Michael Jentschel: Code data that's our current value of the of the atomic of the neutral mass. And the second thing is actually the fact that those three numbers do consider coincide is actually a
Michael Jentschel: Direct test also have the validity of equals MC squared, since they do scatter since the Airbus and not as small as they would like to have them. This is done on a on a relative and certain extent, to the mindset.
Michael Jentschel: Now in this field actually GM six was built to make the next step to
Michael Jentschel: You know, to get those Aero bars down to something below over here and at the same time depending track people they're doing their work. So what you see here is
Michael Jentschel: The paper published in 2017 on the proton mass measurement that this would be this term, sorry, this term here, and I'm sorry I'm going the wrong way.
Michael Jentschel: And now on in September 2020 you see also the according daughter and mass measurement and you measurement and what we would be needed to deliver is a wavelength measurement. However, I have to say.
Michael Jentschel: We did not succeed and we did not succeed for statistics reason because essentially this is when the instrument was shut down. So this is what the last 10 days have come six running
Michael Jentschel: Very trying to measure that. And now you could ask why.
Michael Jentschel: Why did we spend our time not measuring earlier. The reason is to make a precision measurement you need a lot of time.
Michael Jentschel: To set up an instrument to measure very accurately, so we had to spend a lot of time and getting systematics right before taking taking statistical data. And at the end of the day, turned out that
Michael Jentschel: There are statistics significant is not better than the one of this measurement here. So, there will be no new value for this new term us out of, out of those six measurement because simply for statistical reasons, however.
Michael Jentschel: Chose if GM six or if those instruments would still exist. We could have probably provided quite competitive data.
Michael Jentschel: Now since time is very much advanced
James Smallcombe: And we'll skip this point.
Michael Jentschel: Okay, and I will essentially speak on it, but one slide about the reason why these instruments don't exist anymore. And then I say one words, though, where I believe they will exist in the future.
Michael Jentschel: Is this okay or is this my tool for out and timing.
James Smallcombe: I would you say we've have gone over the hour and started losing a good chunk of the audience, I would anything you really want people to see. I would probably skip to that.
Michael Jentschel: Okay, essentially.
James Smallcombe: The reason is
Michael Jentschel: We cannot build in such a B2B anymore. The legislation, the, the laws have changed so much that technically
Michael Jentschel: We are not able to building a beam to anymore. And since we don't have the beam to be kind of operate the spectrum means anymore.
Michael Jentschel: So this is the reason the technical reason why this spectrometer on standby.
Michael Jentschel: And the future. I believe that to be is actually in combination with something like a Juniper demaree source. Okay, so we will have in the future, Eli in P which is a if you see a compact scattering source envision electron beams comp scattering
Michael Jentschel: Laser or come up scattering, a laser photon to be a gallery energies and though this is a forward emitted quasi monochromatic gamma radiation. Okay. However, this gamma radiation is not monochromatic enough for doing look at the resonance floors and it's only 10 to the minus
Michael Jentschel: 10 to the minus three. So if you work with the parameters of such as such a source like Eli and p and you look what the signal to noise ratio will be
Michael Jentschel: In an interactive experience, you will see it depends very much over that. That's okay. If you have a heavy that nucleus, it will become very, very bad.
Michael Jentschel: So I skip that we did some do experiments on that and showing that if you would go, let's say, from an aisle, but I'm going fast. Now if you go from
Michael Jentschel: A light nucleus where this is the physical to something heavier, you would be completely dominated and the conference gathering
Michael Jentschel: From the target. So what you need to do you need a monochromatic this radiation further to push this line here, which is down to the green line.
Michael Jentschel: Which would be if a GM spectrometer would sitting behind it. And the fact that it is possible. They have shown you, and simulations that this is if you want a monochromatic city of the
Michael Jentschel: comp backscatter and source. The pink line a single trust of letters would already Monaco monetize it by that much. And if you would put in something like a gums, you get to this.
Michael Jentschel: To this monochromatic city. So I believe that the combination to the future of this technology is not going to be probably anymore.
Michael Jentschel: At the massive for pie emitting photons source, but it's going to be at the form of directed think and it's gonna be fun looking at photonics rather than let's say spectroscopy of
Michael Jentschel: Isotopes excited by by nutrients and by that I would stop my talk, and I admit, it was a bit too long.
James Smallcombe: Right, very much, Michael, I think it was well worth the
William Gelletly: Length
James Smallcombe: I never get tired of looking at those kind of spectra. They're fantastic
James Smallcombe: So, so let's have our final question session. For those of you that have
James Smallcombe: stayed for the entire talk. So again, in the participants menu, you can go into the new see the raise hand button or type them in the chat.
James Smallcombe: And I see bill to let these again unmuted. So I assume has a question, Bill.
William Gelletly: If I enjoyed it. Michael
William Gelletly: Me reminded me of doing experiments earlier, though. I was wondering if, would it still be possible to pretend a suitable being to say to the Munich reactor. Of course you wouldn't have quite the same flux, but still
William Gelletly: Might be able to do similar physics.
Michael Jentschel: Okay. So, as you know, the Munich reactor does have this rule going beam to
William Gelletly: Mm hmm.
Michael Jentschel: And you probably also know you do need a struggling been to, or you don't need to actually through going, but you need at the end of the game to be as far away from the core
Michael Jentschel: Because you don't want to add the end acting as a company together.
Michael Jentschel: For your edition. Yeah, so the Munich, the Munich beam to was Ben. It would have been a maximum of flux only affect the two words than ours. So what would have been interesting.
Michael Jentschel: But for a project called math that you might know about it was actually moved out of the maximum because math was supposed to be.
Michael Jentschel: Efficient fragment separate a very we're doing fishing inside and you didn't want to heat up that thing too much and you didn't want the dinosaurs too quickly. So it was put out of the maximum. So right now it's in the wrong place. Okay, so you cannot put it there anymore.
Michael Jentschel: Building a new been to been. I don't know. But there is a reactive chess, at least the structure for a lot of such beam tubes and it was originally for seen him having forward and financial
Michael Jentschel: Which is in. Gotcha. The peak react to the new one and it's 100 Meg address. So I myself or several times they're proposing myself.
Michael Jentschel: But I should say.
Michael Jentschel: Over the course of the time the number of beam teams, they truly believe in God, reduced to one.
Michael Jentschel: And it's in both cases, though in the Munich one, and as the one that gets you know they want to put an ultra called nutrients forced into that. So,
Michael Jentschel: Again, also at the the gotcha director. I'm not sure how long those been tips will be learning because this is 100 mega director. So if and again it's aluminum. So they probably have to change been tips every three years or so.
Michael Jentschel: So,
William Gelletly: Surely we have can be designed in a different way. I guess so that you could readily change them.
Michael Jentschel: You could, you could have made ours. And so the last change. He could have made ours to be out of turquoise
Michael Jentschel: And it would have lost over the lifetime of the island and it wasn't only today's standards and only 400,000 euro question.
Michael Jentschel: If he would have done that at that time would have been cheaper compared to all the tests that you were running over the last three years.
Michael Jentschel: To figure at the end of that we cannot deliver them because we've actually we're trying. We did. We did run three years technical test how to build on the beam under the new legislation and you fail, I have to say.
Michael Jentschel: So it's, it's a pity, I have to say, but I cannot blame really anybody because everybody did
Michael Jentschel: What he could I can play lawyers, if you want.
William Gelletly: Well, I must say enjoy the talk a lot.
William Gelletly: When good thing is what I hear a lot of gamma ray spectroscopy just talking about that germanium measurements as being high resolution and I guess this is largely because they're ignorant of what you can do with a deflection spectrometer.
Michael Jentschel: I think the ideal world, and actually why I have been pushing so much for folders, give it gamma rays at the at the ILO and I mean I could always I said that's the Congress, don't do this, you kill yourself.
Michael Jentschel: Because I was deeply convinced that the complimentary is actually what is, what is the absolute killer. If you can do coincidences. You can do angle a correlation you and you can do very high resolution with the same reaction that's, that's, that would have been the thing to go for
William Gelletly: Okay, very good.
James Smallcombe: Okay, I asked the question kind of related. So has anyone ever thought of a way to try and do coincidence measurements between, say, a traditional detector and gamble or something similar. I'm not entirely sure how you achieve that geometrically.
Michael Jentschel: Well, okay. The first thing you have to come back to the solid thing okay the solid angle of the to beam two axes that you would have okay because this
Michael Jentschel: 10 to the minus six on each side. Right. So you multiply the two things. It's 10 to the minus 12 just to get it to gamma rays out of the be
Michael Jentschel: Now, one guy. Let's say you have 100% efficiency detect on one side, sitting and that's a big fat simulator. Okay.
Michael Jentschel: But then there's the deflection parts that you can. So it's another another two or three or four orders of magnitude that you will be adding you down into 10 to the minus 16 or something. And there is no bloody flux
Michael Jentschel: This is, this is the pity. The only reaction that this would make sense. And we tried to be honest, we tried it and we fail.
Michael Jentschel: Is a pair
Michael Jentschel: And undulations of patterns that we have to to 511 going out. Okay, then you don't lose. And we tried to do it because we wanted to measure actually the 511 energy
Michael Jentschel: A correctly. Okay, so typically it is 1022 and some but it's Doppler broadened on, you know, if you just measure one
Michael Jentschel: So if you would get a correctly. The second one, the some of those would make it to the 1022 and if you go to measure that you have again an energy equivalent to a mass which is actually the same as equals MC squared, that that's the only one. And I have to say, we tried it, I think.
Michael Jentschel: Two or three weeks. And it's, you must run coincidences over very complicated. You know, it's by things 100 meter cable running over many other instruments and we never got this thing really well running and this I have to admit, no you didn't get it running at all. So,
Michael Jentschel: Blame it, maybe that's a project or should have been a project, but we failed. So we didn't do that. Other things to do with
Michael Jentschel: It's it's it's a beam time questioning you know the user facility, you can just send forever and one crazy idea on some stage or user will knock on your door and say, Look, guys. It's my turn.
Yeah.
James Smallcombe: Okay.
James Smallcombe: Do we have any other last questions I always say, you're welcome to unmute yourself at this point. If you don't have the raise hand button.
James Smallcombe: But I don't see any. We've got some digital clapping people who appreciate the top. Yes, I think. Great talk, but no other questions. Okay. So I think was wrap up there and say thank you very much for different features and giving a great talk. Michael and thank you everyone for joining us.
James Smallcombe: And have a good week.