Sergio: I
Sergio: Just want continue
Sergio: I just want to point out that I'm an astrophysicist with an eye to nuclear astrophysics so
Sergio: I apologize. I apologize in advance if I'm not providing too many technical details about the nuclear experimental equipments.
Sergio: On the other end. Consider today's audience and I will mainly focus on the nuclear part and I will not enter into the details of the stellar modeling. I hope to have found a proper compromise, so
Sergio: Here is the outline of my talk, I will briefly introduce
Sergio: The two major neutron capture process working in the universe and a corresponding stellar sites. Then we learn again and briefly introduce galactic Chemical Revolution models and the so called residual method.
Sergio: After data will focus on some
Sergio: Nuclear and experiments I participated. The first is the guardian when under 54 and gamma reaction studied at an offer at CERN and get enough, indeed, and the crypto neutron capture measurements performer that they sort of
Sergio: Facility in His Word. And finally, I will also deal with efficient reaction again attend of and
Sergio: Briefly explored possible interesting improvements we the high energy is old, so this is most of your already
Sergio: So these bloating, which the solar abundance is a function of the nuclear number are plotted and as you can see, starting from Ireland on there is an almost exponentially became profile with super imposing some peaks. So the idea is to understand what are these peaks and we know that
Sergio: These peaks, Andy. As you can see, these are connected to the our process and the process. So all of these elements cannot be synthesize it via charged particle reaction you today, Columba year and so that the only way to synthesize them are via neutron capture reactions.
Sergio: And an important point is that neutron capture a cross section in general, increased with decreasing energy and this basically allows to synthesize elements via neutron capture processes.
Sergio: The two most important neutron capture processes in the universe are the so called the rapid process in which the
Sergio: Beta decaying time Scott timescale of the unstable fresher synthesizes isotopes is much higher than the corresponding neutron capture timescale, and it is characterized by very, very high nutrient dense cities and this low processor in which
Sergio: The day unstable synthesizer isotope have time to decay back to their stabilized us in this case we are dealing with the nutrient density of about 10 to the seven neutrons per cubic centimeters.
Sergio: In principle, one could expect to find a range of stellar neutron flux is in the universe. Actually, if we ignore the so called intermediate process they I process.
Sergio: Which has been
Sergio: Studied very much in these last few years. But in any case, it's a minor component of the
Sergio: Chemical enrichment of the galaxy. The most common flux is are either quite small, or quite large. And this was already very well known.
Sergio: By those people barbarous Barger follow boy already in the 50s. So how does the process work so yes process. As you can see, proceed very close today. So call it beta stability valet. As you can see I reported only the stable.
Sergio: Isotopes and as soon as an unstable isotope is is encountered indicates back to a stable one.
Sergio: As you can see here I magnified this region and this is the region with a neutron magic number and equal to 50 and in correspondence of this clause chair configuration. There is a sort of bottleneck ODS process and some isotopes, like for instance.
Sergio: Have more I have larger abundances we do expect to the closest isotopes on the other side. The our process proceed very far from a bit of stability Valley.
Sergio: And until the reason a large enough neutron fluence as ESA the neutrons basically are no more available then again there is a clustering around the neutral magic number isotopes, which
Sergio: Decay back today have stable eyes of bars when there are no more neutrons. And as you can see you have clustering advisor to
Sergio: Our abundance is here and here. And so basically, there is this is the reason for which you see double pizza in the Solar distribution. I just showed you before.
Sergio: So if we have a look to the end to this nice block figure which describe which are the stellar origin of the heavy healing mentor you see that starting from strontium to uranium and so on.
Sergio: You see that the only two callers are
Sergio: Dying Loma stars and merging neutron stars. In fact, if we have a look to the which are they, and where do DS process and the process of Korean the universe we can basically
Sergio: Identify four sides. The main s process and the main our process our respectively synthesizing in us in total giant branch stars and neutrons don't know just
Sergio: While the weakest process and the weaker process which interest isotopes up to a mass number or equal more or less to 90 are
Sergio: Synthesizing in the client question burning phases of massive stars and in the exponent faces on my sisters, but this is still a matter of debate. So let's start from a very, very short introduction to add stars.
Sergio: Stars are stars which are trying to the red giant branch for the second time they already exhausted either agenda and helium at the center. And in fact, the
Sergio: Structural resembles no noon we the carbon oxygen bursary degenerate core surrounded by any new shell and and I project shell this core is
Sergio: Floating in a extremely expanded and cool convective envelope.
Sergio: Half of the heat elements here. Then I on our synthesize it in these objects. The remaining alpha is synthesize it by Dr process. So, actually.
Sergio: There are more than that. There are many proposal side to be the host to host the ADR process. I just mentioned the
Sergio: three most important ones which are Magneto rotational driven supernova, which is a particular class of supernova, in which very powerful magnetic fields.
Sergio: trigger a very rich our process look Lucien, this is there are magnets, which are basically connected to a Christian discs around black holes. And finally, there are neutral stammer just did it is the final
Sergio: Moment of to neutron stars or between one each other. And at the moment they contacted the reason a very large increase of the temperature and the densities are very high. And considering the matter or which they are composite which are basically neutrons.
Sergio: A very original synthesis can be obtained it obviously among these three classes.
Sergio: The only proof that the our process is working is at work in this star in one of these objects are neutron star merger thanks to the detection of the gravity waves from the GW 17 oh hw event to which, following the killer Novi, Michigan, and from the infrared ray brightness of this
Sergio: Event, it has been possible to derive the presence over here. Humans and another fact that doesn't help in discriminating between doors sites is the fact that
Sergio: tuning the parameters of the simulations, you can obtain more or less same results. And in fact, in this plot, I reported three different
Sergio: Comparison.
Sergio: To
Sergio: All the theoretical curves with respect to observation. But the important point is, what are these observations.
Sergio: So if we start from the
Sergio: 60s. It was already clear that this process is following a more
Sergio: Let's say and modeling path would expect to the process when there is no way to reproduce it with simple rules so that it has always been following this call it the residual method that is in order to determine the our process contribution to the sun.
Sergio: We subtract to what it is observer the corresponding s process percentage and in such a case, it is important to have galactic chemical evolution models.
Sergio: Which include accurate as processes to provide a reference to our process calculations, we did it in the last two years, and as a couple of paper, I suggest to have a look.
Sergio: Where we basically adopted stellar year so low massive, massive stars sharing the same metrics code and those models are available.
Sergio: On the free database with page and the orfield database with page. If you're interested in and what we obtain is that
Sergio: We can reproduce within 5% 36 elements out of 51 consider that in this simulation we pause
Sergio: The bonuses of trance Ronnie key elements. We basically and considering they contribute from this quality process, which is a minor process, but which is important for instance, for example, for Molly Bruno.
Sergio: For the formerly dinner we are able to reproduce within 5% most of the observer elements and for each element, we can derive the solar s and our NP components, but
Sergio: This is related to elements. We can even go in further details and we can have a look to higher ups in particular on the S process path. There are some isotopes, which are named as only which are shielded by any possible our contribution from Dave stable eyes Abbas, so that this
Sergio: Is adopts provide very stringent control constraints on the stellar models of the S process. And if we have a look to the comparison between what we obtain and what it is absurd. But you see that we can reproduce within
Sergio: 5% a lot of
Sergio: Isotopes the blue.
Sergio: Dots are mixes eyes of abilities isotopes, which are similar contribution from DS and from the our process. Why the
Sergio: red squares are the circle. It s only isotope so that only AG be stars and massive stars pro provider. They saw our contribution to those isotopes and
Sergio: It is already a very nice result to ever painted. We did 10% more or less a flat to distribution in accordance with the sun. However, as you can see there are some evidence is that there are some problems. And in this talk, I will deal with this guy, which is
Sergio: That as you can see it is under produce it in our modus and create them at and
Sergio: Directly related to the creek. The neutron capture measurement also strontium 86 and strong. So Edison. Let's start from gadolinium the energy of interest for
Sergio: For the production of this element in stars, ranging from ranges from about seven kV to about 35 kV and in other motivation, which she does to measure this.
Sergio: Is the neutron capture cross section of this as a top is the fact that there was a large disagreement in the literature.
Sergio: So the first measurement that was performed at the end of a silica sand and tofu is a neutrons palaces source based on the PS at Sam in which brought phones at very high energy are accelerated and
Sergio: To hit a target, which basically produce a is a large number of
Sergio: Particles, among which neutrons which fly by for a about 190 meters and arrive to the experimental ARIA, these, these are, these are some figures of the
Sergio: End of experiment flight Potter and diseases. A image of the
Sergio: Variant experiment or setups. In this case of 66 simulators and I didn't have that is this was the first experimental ARIA
Sergio: Later, it has been constructed a second experimental area which is above the pollution target that this color here. And now the reason construction. A third experimental area. There's a colony or station which is very close to the
Sergio: To the target. They the interest of the second experimental aura is that the fact that the neutron flux is definitely higher and it'll load in the past to measure.
Sergio: The cross sections of the on unstable isotope. So who's the natural activity holder basically wars and the measurement itself, but we with the collaboration manage it in GUI, for example, on the burrito NP and an alpha cross sections.
Sergio: In turn it off. Basically the neutrons are eating a target and then what we are going to measure is to the GM or a cascade of the compass it exciting new clothes for what concern gadolinium we had we use it a sample of about
Sergio: 206 zero to 26 grams and Richard in petroleum. One of the 54 and the measurement has been done in 2017 then we the same sample, we went to Gail and where there is the galleon of facility galeana is a facility constructor to measure.
Sergio: Cross section in the result but and are resolved within our region. It is a multi user to facility.
Sergio: And all this facility. This experiment can be performance simultaneously and in this case.
Sergio: An electron beam. It's a mercury called uranium target, which produced brain cell brainstorm radiation and subsequently neutrons buyer for two days integration in this case, basically.
Sergio: Neutrons are passing passing through the the sample and what you measure is the number on neutrons. After the sample and basically what you measure it this transmission, which is related to the total cross section which is this some of the capture and of the elastic.
Sergio: Neutron
Sergio: Cross section.
Sergio: Basically with respect to end off there are less neutral, but we deny a high energy resolution and this is an example of the combine it captured blasters mission measurement. And I remember he that
Sergio: Didn't have we mentioned the capsule wallet good enough, there is the measurement of the total cross section and what we obtain
Sergio: Which is a very nice result that is that we found the cross section which is on average 15% lower than the
Sergio: Cross section use it in most of stellar evolution record which is a day, which are they the yellow dots and what's the result concerning the nuclear synthesis it that we can uncertainties. Now, the point
Sergio: Updated by models. We just perform some milk some more that we should really compute all the models, but this requires time. So, but what we expect that is that
Sergio: The new measurement. He then the new model we model with the new measurement is we do not certainties in agreement with observations. So now we can
Sergio: pass to the analysis of the creek don't cross sections in this case this measurement is be performing that sort of stuff is a sort of applied research facility to facility.
Sergio: Is an Israeli national infrastructure for applied in buzzing research and the Coursera consists of a light high and superconducting linear accelerator. In this case,
Sergio: There is a problem been which is eating a liquid, liquid target the so called elite target and
Sergio: Which produce neutrons via deleting seven piano reactions and we in this sketch in this block, you can see where the Krypton sample have been
Sergio: Put in this case it's not a tough facility like and tough Angelina, but it can be
Sergio: tuning the proton beam to reach in, in almost mockups or enormous mcwilliam original
Sergio: Distribution all the new transfer eating the sample and once they measure has been performed them. The sample is removed. In this case, you
Sergio: We are interested in measuring the neutron capture cross section, but actually we are not measured in your trunk up Sukkot section, but we are measuring the decay of the
Sergio: Freshly synthesize it unstable unstable isotopes. In fact, it is an activation measurement you counter the decay from the stabilizer Boston in particular.
Sergio: We count the curriculum at one the crypto 87 and the creek don't 8585 or whatever it is important to stress that DS process.
Sergio: There is a branch of this process because the critical 85 has a ground state and a nice summer state which are not normalize it understand our condition and it may happen that some of the neutrons captured by 84
Sergio: Synthesize 85 which rapidly decay back to rubidium 85 while some of them decay by gamma transition to the ground state, so that it is a very complex a path to be followed into the detail, the results are slippery minority but
Sergio: The most important part, I would like to stress is that the new measurement provide a cross section for Krypton at which is lower.
Sergio: Than what it was previously the adopted and while for the Krypton 84 we obtain more or less the same cross section, but we'd a nicer top and a nice old man.
Sergio: To the ground ratio completely different with respect to before, in the sense the isometric
Sergio: State is favourite with respect to the ground state. Moreover, at. Finally, we also take a login Krypton at six.
Sergio: Cross section, the results are which are which are, we are still discussing are interesting because, in particular in massive stars.
Sergio: There is a very interesting production increase production of Rubidium 87 which propagates that too strong to mediate up to their community and, moreover, and there is any unanswered production of
Sergio: Which are both
Sergio: S only isotopes. So again, we just calculated some models, but we expect that more or less the situation is the same for all the models with what we find is that now they clicked on at
Sergio: Theoretical a bonus is in better agreement with the sun and as well. It works for the strontium 87. However, we have a problem because we increase a lot the production of strong some 86, and for this reason.
Sergio: Other models will be a computer that in the future to check if these results are configured for all the classes are models with different masters and different modalities, so
Sergio: Up to now, I just concentrated on the S process. What can we say about Dr process. So our process calculation need the very accurate data on unstable nutrient rich isotopes. I'm not going to describe all the techniques and facilities available to measure doors.
Sergio: For example, masses.
Sergio: And beta decay timescale efficient rates and so on. And, but I just want to under underlying that there are many facilities in the ward.
Sergio: Which are already working like the one or Rican, but under construction, for instance, that is fair and you saw or free ban and miss you and
Sergio: Other wanting to work in Korea and in India. And finally, there are spirits to agony and the space at the NFL, or the linear or in Italy. However, I'm concentrating more on a specific
Sergio: Part of their process which is connected to fish on
Sergio: If you go to observe stars or very low metal listen in the center of our galaxy which is basically
Sergio: A sort of a sphere.
Sergio: In blubbing the disc of our galaxy and you have a look to the stars and present in this regions, you see that those basically those stars are and they in most Pura
Sergio: Sure. The most pure abundances which experience at the lowest number of nuclear synthetic episodes. In this sense, I consider that they are starts with a very low metal. The city. It is. It is, as you are going to
Sergio: Check back in time and you can see what happened at the early stages of our galaxy. That is exactly when the airport, our process is so to
Sergio: Shape the observer distributions and if you have a look to these distributions. These are stars which are simply scale it for a week visual
Sergio: Reason, but if you ever look to the relative distribution of all these elements you see that starting from an atomic number of 55 up to 80 all of this.
Sergio: Stuff stars show the same ratios why there is a scatter for the light part. So while this part is probably connected to other our process.
Sergio: And enrichment and and probably they're connected to the so called weaker process this star these elements belong to this quality main our process. And as you see there are very, very constant
Sergio: Among in the sample. And why are these stars. So these measurements so Kong start from there. A relatively point of view. Well, because they are the product or the so called official recycling when you have a NR process.
Sergio: Event working in your seller side which is a neutron star merger or a magnet, or whatever you want. You are proceeding as I
Sergio: Said before very far from the beta stability ballet, but at a certain point you are either in this region where there are the transatlantic elements which are suffering for fishing, which can be
Sergio: Spontaneously delayed or Newtonian use efficient. So basically, from here you get go back here and this process of course many times during the evolution of this
Sergio: Event so that
Sergio: You have a sort of us in toxic.
Sergio: regime in which all the bonuses reach the synthetic value and this is the reason for which you absorb constant distribution in low mass
Sergio: Low metal is the stars and they insensitivity of the strong our processor bonus Potter is directly
Sergio: Related to the extremely low wine bottom and what's why, why isn't simply the number of a number in the number of protons divided by the number of nucleus. So if you have very low way to means that you have a very nutrient rich environment. So if you have a look to the distributions.
Sergio: This is their receipt or our process distribution. I just discovered before compared to different in this case mass murders and you see that there are still some
Sergio: Evidence that in some parts of the distribution. There could be some problems.
Sergio: In fact, a key nuclear physics quantities related to our process modeling as our ad muscle mass murders bakeries and Fisher models, in particular, the latter.
Sergio: And they they turn mine the position of the third pika and deficient Franklin distribution shape for the region close to what sorry shape their regional close to the second peak. Because basically, it is the dominant process.
Sergio: In this region or the topic chart so has already said in as a physical calculation three different types of visual are considered middle efficient.
Sergio: Efficient and neutron induce efficient and it is very important for nuclear synthesis codes to have a very precise efficient means now fishing yields.
Sergio: Are
Sergio: For new very neutral rich isotopes are mostly derive it from a theoretical point of view, however does fish on models.
Sergio: Have to reproduce the observer fish on properties have known isotopes, and for as, for example,
Sergio: The, the barriers delivery density is above the barriers and so horn and more often in particular if the energy of the cutter a neutral nice enough to remit neutrons.
Sergio: And activate efficient process, there is this called multiple chance fishing and in this case, having a series of isotopes of the same elements studied in a very careful.
Sergio: Manner. It is important to constraint fish on models. I tend to offer in the pastor. We many isotopes have been measured I basically all day so can say stable.
Sergio: Eyes of like tutorial of authority moronic and plutonium, but also and measurements of memories human curium AS BEEN I'VE BEEN AT performance and, in particular, I want just to stress that for what concerned a Korean 245, the results are in extreme
Sergio: Are extremely in accordance with the available measurement, which I've been done by studying and nuclear explosion bombed and these basically test the goodness of the measurement performance at end of UNFORTUNATELY IT. IT IS A REALLY MATTER OF THE LAST WEEK'S
Sergio: Let's say monster in the future, etc. The there has been a change in the policy of radioactive waste locking and we are still verify if other measurements will be performance or not. And I tend to have. There are different types of
Sergio: experimental setup which include, for example, my Chrome is a micro Magus chambre sir, the so called people counters and all of them are complimentary and
Sergio: Let's say
Sergio: And studied different properties of the fish on prod process, in particular, the very large signal to the ground ratio near to allow the measurement of radioactive isotopes. Also we they fly for as low as a few years.
Sergio: Another very nice instrument, which has been
Sergio: Adopted use it identify his status staff does a color spectrum meter for exotic fish on fragments which is a very nice machine. I don't go into the details because it's not my work, but just to
Sergio: Just want to highlight that it is a two way to be spectrometer. So basically,
Sergio: Did this detection system allows the measurement of both fishing fragments to the measurement of their atomic mass and their atomic number and it is very important if you want to provide again very precise official needs and
Sergio: Now the last argument, I would like to touch it, which is something which is very new and I'm not directly involved, but I find extremely interesting for the future. Sorry, I forgot to say that
Sergio: The
Sergio: Regions for OB interest for the
Sergio: Fishing.
Sergio: He is from a physical point of view are the nutrient rich isotopes of plutonium and uranium curium, so this is the reason why we are planning to concentrate on these
Sergio: Elements and I just conclude by saying, and showing a couple of slides about the high energy, high intensity high energy is all the facility.
Sergio: Which is going to be installed in this moment and will increase the energy of the original cloud beams from three MTV up to 10 min movie and
Sergio: And in such a way, it will be possible to accelerate heavy nutrient rich nuclei to energy above deficient barrier and study deficient.
Sergio: On advisor tops relevant to their process, but also including obviously unstable isotopes of the transatlantic elements. And I want to thank some well and Toby who busted me this slide in which
Sergio: It is show a proposal to study transfer Indonesian fisherman in inverse kinematics with certain order spectrometers at his older taking advantage of the
Sergio: SSD is also another spectrometer, which basically
Sergio: Transports with high efficiency charged particle emitted your the nuclear reaction and to an array of the silicon detector was mounted on its axis. In this case,
Sergio: The proposal is focused on the DP reaction which is a surrogate for the and Fisher reaction. And as you
Sergio: In this case, fishing fragments are detected in the efficient fragmented and deification detectors and multi wire proportional chambers.
Sergio: This is very interesting because again you see that the possibility and these are the isotope for which there is a possibility to have an intense beam.
Sergio: Is all there. And you see that there is the particle related to plutonium and isotopes, which are the most interesting for fishing yields. But the other important thing is that you can also study
Sergio: Radioactive isotopes with I fly for which are of the order of ears and in this is very helpful to constrain again and fishing models because in this case the experimental
Sergio: Number of constraints will grow and will allow a better tuning of the fine tuning of the parameter of the theoretical model. So I basically stopping here and I thank you for the attention and I'm waiting for question if there are some
James Smallcombe: Thank you. So y'all have a great talk. Lots of interesting different experiments there.
James Smallcombe: Yeah, we have.
James Smallcombe: Any questions, please, just as I said before you go to the participants menu straight off the bat, the bass. Would you like to turn your cell phone and go ahead with your question last
Sergio: October.
Tobias Wright: I said her. Can you hear me.
Tobias Wright: Yeah, yeah. Thanks very much to talk really interesting and I was just wondering, you said at the start, for the S process. The key neutron energy and range was sort of kV like 10 to 35 kV or something like that.
Tobias Wright: Yeah, for the our process. Do you have a similar kind of QA enjoys it more. And because you showed one plot where it was just EV resonance region.
Tobias Wright: And then it will talk about
Tobias Wright: Multi chance fishing, which is
Sergio: Ya know, so did
Sergio: They gain gain energy of interest should be some MTV.
Sergio: Okay, because more or less. It's the the NL gated content your perspective in the actor of those nutrients damages and we are dealing with completely different energy origins
Tobias Wright: And do you in your models do you take into account the fishing yields change as a function of neutral energy, would you just choose
Sergio: A. So at the moment.
Sergio: Let me think about it because we are still a, let's say, at the beginning of the from my point of view, I'm still at the beginning of the nuclear synthetic calculation, because
Sergio: My 40 s process, it's more or less 20 years and working on that for the process of just started last year with the Gago my PhD student
Sergio: And but yes they are deficient years our energy dependent temperature dependent. So basically it means that they are energy depend. But let's say that
Sergio: Deficient yields you we can use are very, very rough from, from what I understand, I understood. So there is very plenty of room for improvement of them in the future. Okay, thank you.
James Smallcombe: Okay, we've got a question lined up from Nico. Please turn your cell phone. Go ahead.
Nico Orce: Thank you so much. Sergio, I, I've seen your, your plot on low mentality. The stars coming, coming from the halo of the galaxy.
Nico Orce: Yeah, and how the process is dominated by the efficient products, but I was wondering about this is extremely meta Pura stars do they, do they account for those are those don't have
Nico Orce: Most of the heavy elements that we see in Norma oh
Sergio: Well they they inherited day distributions from other events they simply format in in a brothel stellar nebula, which were I've been polluted by
Sergio: Previous event. So there is there is a debate now concerning. In fact, which was the polluter because if you have a look to
Sergio: Loma felicity stars, it means that those stars format in the first hundreds of million years when our stars format. And if you ever look to the time scales for neutral mergers to arrive to the to the merger itself. It may take also giga years
Sergio: And for this.
Sergio: For this reason,
Sergio: Why
Sergio: There is a strong debate on that on the fact that there are people we say that
Sergio: Our Passion Magneto rotational driven supernova, because in this case.
Sergio: You don't have to wait. The time for the two stars to merge.
Sergio: However, in this case, there is a problem that are those rotate the rotation rates they need are very, very I and
Sergio: There are other research. I'm not an expert on of this particular modeling we who say that they are are reliable. So in any case, the fact that you see a normal constanta
Sergio: Behavior relative behavior means that you saw the original sin porting values. And as soon as you have very low.
Sergio: Very high nutrient density, which means very low ye you pass through efficient. There is no way
Sergio: I hope to have answered your question.
Nico Orce: Yeah, but I wanted to add to that the the theory, the original theory was that most of these elements were previews because of the timeline.
Nico Orce: Through this supermassive supernovas right massive stars at the beginning this population, whatever it's called, not one, but two or three these massive stars that were created at the beginning, after the Big Bang.
Sergio: Haha
Nico Orce: Through the supernova explosion created this this first elements, right.
Nico Orce: Or that we see in a movie stars are we seeing all the it is very, very
Nico Orce: Very low mentality within meta pool stars.
Sergio: Okay. And so what's the so
Nico Orce: What I want to say is that also supernova. If you said that you throw murders take long time to be
Sergio: High. Yeah, yeah, sure, sure. Oh yeah, sure, sure. Yeah, I agree with you. It is a i was i was fixated on the, on the, the only for dinner, important thing is that you have a low way.
Sergio: Which can be Richard in neutral summers, as in supernovas has in monitors and so on. The important point is that if you don't have a No way. You cannot reach the inefficient production of these elements. Hmm.
Nico Orce: Thank you so much.
James Smallcombe: Okay, two more questions. I think Paolo was first. So if you'd like to go ahead with your question. Yeah.
I said,
Paolo Finocchiaro: Concerning his older so one of the latest lines you shows. I was wondering about the energy. You said that the the species that have to be accelerated okay after 10 a movie, but these means that you're working in inverse kinematics. So area which is the effective range of impinging newborn
Sergio: Oh really don't know perhaps to be as as some idea.
Paolo Finocchiaro: I think, you know,
Sergio: I i'm really new to this new to this facility.
Tobias Wright: Yeah, I mean, probably, there's some people on the call had Dave Sharpe, who is working a lot on ISS and Sam who's done calculations on it, but depending on what reaction you do, then you can have a range of energies. And so in our planned in our planned measurement with ISS, we have
Tobias Wright: compound nucleus energies from like below the fishing barrier to above the fishing barrier. So it should work.
Paolo Finocchiaro: He meant
Paolo Finocchiaro: So that's different.
Tobias Wright: Yeah.
James Smallcombe: Does anyone else want to comment on that. I think we've got Dave and Robert on the call otherwise.
David Sharp: I can comment if you like just to
David Sharp: Just to
David Sharp: confirm what Toby says that was looking at populate states in the company. Several me be above the deficient barrier.
David Sharp: About these been manages
Robert Page: Yeah, maybe I can just add what the ISS gives you is the tag. If you move on to the next slide, Sergio
Robert Page: Yeah, yeah, you can see the helical red car that's a proton that goes back from the DP reaction where the neutron is captured
Robert Page: By measuring the energy and position of that proton in the array, the ISS, you actually know the excitation energy of the state will the station region that you're populating in the fishing nucleus. And that gives you a very nice probe of what's going on with efficient barriers.
James Smallcombe: We've got another question from Sam. Sam, would you like to answer your question.
sam bennett: Yeah. Hi. Hi. So Joe. It's a bit of a general one. And do you show all the plots where you compare like
sam bennett: Calculated abundances to the solar abundances but it goes. My question is, um, I mean, how do you know that the sun is
sam bennett: Not living in some special part. I mean, how did this whole system is representative basically the whole of the galaxy. I mean,
Sergio: That's a good point. Thank you for requesting we
Sergio: If you want to compute a galactic chemical evolution model, you have to assume that otherwise.
I guess.
Sergio: all all all of these calculations are useless.
Sergio: What you can do is to observe the solar the solar on a boat and check if you find some strange behavior of, I don't know.
Sergio: Some other elements with respect to the sun. What it is observed is that
Sergio: On average, there is a sort of a homogenized it in the Solar enabled so that the sun can be used as a reference term for the evolution for the Galactic Chemical Revolution. Then I fully agree with you on the fact that the sun is one star, which
Sergio: Surely migrated from another region of the galaxy and
Sergio: The best you can do at the moment, I would say.
sam bennett: Okay, thank you very much.
sam bennett: Okay.
James Smallcombe: I just like to invite anybody who's not able to Matt use the raise hand button if you just want to unmute yourself now and go ahead and ask them questions. Another question, Michael.
James Smallcombe: Please go ahead. Michael
Michael Paul: This is my photo.
Michael Paul: I have a question about the process, although we were in contact about the process, but now you regarding the three. The three magical sites for me yes process that you mentioned the neutron star merger is of course in
Michael Paul: Question is among these different sites. Is there any observable, which would which could differentiate, for example, is it, is it clear that the whole process expected from some other super normal whatever type
Michael Paul: Whether these distribution or a process of the same
Sergio: Or yeah, it's, uh, let's say, the key question about the our process in these in these
Sergio: These days because them and
Sergio: Let's say that two years ago.
Sergio: The our process was just synthesizing new toaster mergers.
Sergio: When I start when I was studying the our process was interested in supernova standard supernova because of the publication or
Sergio: Was like we were in the in the 90s where they state that the our process was working in supernova, but then later they had to retreat. This statement. So the problem is that up to now, there are no proof to decent observational evidence to disentangle the dose.
Sergio: Sides. There is a really recent publication. I didn't have time to read the
Sergio: Published by Mario Sigler first name, who's stating that afternoon cool be helpful to disentangle between Magneto rotation of living supernova. And you trust on managers, because
Sergio: The conditions are so different. And in one case you produce afternoon and adulterate and the India that you don't basically because, in one case you arrive at the synthetic value you do to the official decide efficient society. And in the other case you don't
Michael Paul: God
Michael Paul: You're a vendor reference
Sergio: It's a high Clara either
Sergio: I can send you the paper. I didn't
Sergio: Know, nobody tell
Sergio: Them about that. It's very
Sergio: Very debated and what what what people are all reasoning on his own timescales, basically because, as I already answered before indication neutron summer just you need more time, but if you want an early pollution of the galaxy.
Sergio: You have to rely on magnetic gravitational diverse panel or marketers, which are the same. They don't need the very large times
Sergio: But at the moment, there is no not yet.
Sergio: Way to disentangle yeah
Michael Paul: Okay, thank you. Thank you.
Sergio: So just, just to add another
Sergio: Important point is that in ghosts in some stars are also the
Sergio: Ratio between the transatlantic element from random tutorial. I'd be measured, but that they are the midday observation are still not precise enough to
Sergio: Again disentangle between the classes.
Michael Paul: You, you're welcome.
James Smallcombe: Okay. Do we have any final questions.
James Smallcombe: Again, oh, Sam. You, another question.
sam bennett: Yeah, and thanks
sam bennett: It's about the I process.
sam bennett: So you mentioned that it's a thing, and you kind of said that
sam bennett: You ignore it and after that. So, I mean, I don't know where I'm you know what what discrepancies as it as it been introduced to explain and and what kind of astrophysical site would you envisage it
Sergio: So, okay. And well, again it is a strong debated argument, because there are groups which
Sergio: Stated that many of the heavy elements distribution observer in our stars are directly related to the I process. So, up to now.
Sergio: Different stellar sites have been proposed for instance the process in principle called work.
Sergio: At the beginning of the movie star, a very low mentality for very low masses, because in that in that case.
Sergio: They entropy body are provided by the hydrogen shell is not prevented the convective envelope to penetrate. And in that case, you'd have a combative envelope penetrating the mixing process at very high energy very larger
Sergio: Temperature so that you can have the process, then the process called occur at the end of the movie star. If you I for example, and the so called very late term a passage
Sergio: In which again.
Sergio: Let's say the rule to have the I process is to have material iteration rich mix it a Titan portal. Then there are other explanation massive stars. Sorry.
Sergio: intermediate mass AG be stars are being proposed, there are rapidly a creaking white dwarf.
Sergio: Which are which are in a star some white dwarf accreting i'd origin rich material in binary systems and which are not going to explode like type one, a supernova Supernova but they can synthesizer and
Sergio: Element via the I process. And so at the moment.
Sergio: There are many of this
Sergio: Possibility. I will say that
Sergio: The most ground. The most solid one, in my opinion, at the moment, our rapid you're treating white dwarfs because also from the point of view of them and modeling are the ones with the
Sergio: Lowest number of a doc tuning and but
Sergio: Related to this type of objects, they require a fam right they exist on triple systems have to have triple systems and some
Sergio: statistical studies have to be done to
Sergio: Verify if the number of expected triple system you have is the one you need.
Sergio: But it's a hot topic at the moment. I'm not. I didn't consider it because from, from my point of view.
Sergio: It is a process which can for sure pollute some stars in the hello but concluding that it has an effect on the Galactic chemical evolution. Evolution. It is for me for my opinion a little bit too strong, but that's how they are people can prove that
sam bennett: Okay. Yeah. Thank you.
James Smallcombe: Great before even more questions. So, Albert, I think you were first. If you'd like to ask your question.
Albert Zijlstra: Okay, thanks for for a nice story very enjoyable and you compare the above the sister daughter, son. If you also have to piece on and grains. Let's give a button that says that are more specific to the site that he come from there any pre sort of grains that can relate to the merger scenarios.
Sergio: Not to my
Sergio: Interest. I'm not just scenario, you were
Sergio: This, to my knowledge, know that our brains, which are
Sergio: Ever clear supernova origin. That's, that's the tool for true and. But to my knowledge, others to know the origin, but from my point of view, not
Sergio: To my knowledge, no one is related to neutral some as even because I really don't know if duster can create in this opposite, but it's my ignorance. I don't know really. Dan, the physics of that.
Albert Zijlstra: I don't think we know when the dust code form. And it's also a
Albert Zijlstra: Matter of how long the dust can survive after the information. So we're going to get 10 so how long before the sun forms that you just mentioned to place it will be an interesting thing to look for, I think, okay, yeah. Thanks. Thank you.
James Smallcombe: Okay.
James Smallcombe: And then we have two more. I think Albert, no, sorry, Michael, I think you were first Michael Paul only go ahead
Michael Paul: Yeah, thank you. Your family familiar. Second question, continuing on the I process.
Michael Paul: Are there certain elements or isotopes in in the Solar abundance, which need which need the process to be explained. When after this process, explain the process elements rather when they
Michael Paul: Use our process also. So, where, where is the I process me as as
Sergio: Yeah, that's the point. From my point of view, there are no elements which are dominated by the AI process or
Sergio: Because the problem with the residual method is that
Sergio: Everything, which is not test.
Sergio: Is are
Sergio: A point could be that it's not full are, but there is a little bit of VI, but then you should provide evidence that there is there is a class of objects able to synthesize those elements in a
Sergio: Quantifiable in a stronger with a strong production that there are some
Sergio: Some publication, if I'm not wrong by been Lakota who publishes the some karate chemical evolutionary models in which they state that the I process is
Sergio: Able to provide a consistent amount for some elements, but really, at the moment, I don't remember which ones even because I'm fully sharing with them. These conclusions.
James Smallcombe: And we for our last question from Alberto and
James Smallcombe: If you want to go ahead
Alberto M: Guys have Joe
Sergio: Out that
Alberto M: I sent back to the to the s process.
Alberto M: unquestioned that we when we do measurement of needle capture cross section is the question of the accuracy needed for
Alberto M: A sophisticated modeling.
Alberto M: I know it would be difficult to give a general answer to this. But what is the accuracy that you need for your most sophisticated moments.
Alberto M: Accuracy of the nuclear physics input in terms of capture to section, what is the order of the accuracy that you are, you would be happy with in in making the most recent as processing.
Sergio: Our really difficult to answer.
Sergio: Because, well, I will, I will say it depends on the isotope because obviously there are isotope, which are extremely sensitive to the neutron capture or cross section because
Sergio: They possibly live close to a branching. Indeed, in that case, you need to have a, let's say 5% 10% uncertainty, but
Sergio: Normally these isotopes also dependent on an unstable one which is close to them. And there are only. Theoretically cross section down. I will say, if you can provide
Sergio: All neutron capture cross section also for stable isotopes within a certain your 50% I will be really, really, really.
Sergio: MP 50 because for some of these are stabilize it up. There is a factor of three.
Sergio: And and obviously this is also strongly connected to the beta decay rates as you perfectly well know.
Sergio: For the stable once a while. I will say that
Sergio: 10% error for an experimental point of view is
Sergio: More than good, because the problem with the
Sergio: Distributions I showed you is that
Sergio: There is also stellar modeling, which is
Sergio: injecting a lot of noise and which arrows is impossible to evaluate the air or on a theoretical model. I CAN GIVE, GIVE YOU A derivative, no more than that in some cases you can vary by a factor of two of three.
Sergio: If you are a politicizing a different mixtape or mixing, for instance, for the major neutron source energy be stars, but for other cases, I would say no because as you see that
Sergio: These distribution.
Sergio: The fact that we obtain a sort of flat distribution is a guarantee that we are not that far from
Sergio: The through the fact that there are isolated points which largely deviate from the distribution is a sign that this is something connected to nuclear nuclear problem. For instance,
Sergio: You know very well. I'm waiting for body 134 or season 134 because this is something which I never will never
Sergio: Resolve with a
Sergio: Stellar model because convection, you know, is a democratic process. And if I modified this one I modify also the closest one
Alberto M: Okay, thank you.
James Smallcombe: Okay, it looks like we have
James Smallcombe: Another last question, so what, let's go Miyako you want to go ahead. Yeah.
Mirco D: Hey, Sergio
Mirco D: I knew I was wondering, you didn't talk much about the week our process. So you explain that the side of our process is in discussion over the last decade, well is the different like nutrient density or the mechanism or how they distinguish main and week our process.
Mirco D: Oh, basically.
Mirco D: You showed that for intermediate mass
Mirco D: Elements below a 90 day agreement is not very good yet. So it's, there's a reason for it or
Sergio: Well, basically because the problem is connected to this quantities today why the neutron to see in your turn to the proton to nuclear nuclear ratio.
Sergio: In case of a stronger process, you are working in a range of white, which is very low. So
Sergio: Passing from zero dot 0520 to 15. It doesn't change much distributions, you have a sort of a synthetic regime. If you stay around zero to 3024
Sergio: Then things become very difficult because those conditions are attain it from a theoretical point of view in many objects. You can have a quicker process in law mentality supernova Supernova which are don't need to rotate that much. There is the RFP process. There is the
Sergio: XP process. There are
Sergio: A Christian discs around the black holes again. So there are different classes of objects that can
Sergio: Contribute to this region and for this reason is more difficult to constrain the abundances to constrain the origin of this
Sergio: Week our process for sure there are stars which have been polluted from an object which didn't attend the synthetic value I discovered for new customers because you see a really declining the distribution for large mass numbers, but it is still to be
Sergio: Determined, which is decide. Actually, there is a sort of indication that standard supernova. Cool. Do the job but it depends on the explosion mechanism and
Sergio: The last year's people managing exploring exploring Massey in opportunity explosions, but
Sergio: Yet the local scene disease is not so welcome strange, at least from, from what I can understand
James Smallcombe: Okay. Thanks. Okay.
James Smallcombe: Thank you very much for all of those questions.
James Smallcombe: I think we have about half the audience to snuff off during the question, but we have the highest audience so far. And that was definitely the most active question session. So it's been
James Smallcombe: fantastic audience and also a fantastic talk. So thank you very much. So, yeah.
Thank you.
James Smallcombe: And so I hope you can all join us again for our next session, which is on Monday app again 3pm PST but will have quite a
James Smallcombe: Topic will be going to quantum entanglement in PET imaging that's recently from from University of your 3pm PST for the next session. So thank you once again for all of your very active participation and for great talk. Thank you.
Sergio: Thank you. Thank you to everyone. Thanks James