- Provides information about:
Up to 8 quasiparticle isomers have been observed
(A) When I is large?
angular momentum limit to K ?
(B) When N is large?
neutronrich mass limit to K ?
signature for rotation is collective band built upon isomer.
signature for good K is a well defined or
longlived isomer...
as K and I increase, isomers become more yrast and longer lived!
We have 178Hf and 180Ta
so where are the rest ?
used 1.6 GeV pulsed 238U beam
on most neutronrich Pb backed targets...
186W, 176Yb,
181Ta, 175Lu
12 Ge detectors, 50 element BGO ball
only record data in dark period between beam pulses...
ANL has excellent beam timing
very successful experiment!
many new 2 quasiparticle isomers
in particular found 4 quasi-particle isomer
in 186W
have found new technique to give
partial access to this region.
Theory appears to be correct that the
heavy nrich isotopes still have good
Kquantum numbers !
D.M. Cullen,
P.M.Walker,
G.D. Dracoulis,
P. Chowdhury,
I. Ahmad,
Back to Nuclear Structure Home Page
Last modified: 23 February 1998
- Gives us access to a Quantum system.
Classic Probes of interplay of collective
& singleparticle motion.
As always this is where we learn the physics!
Is K a good Quantum Number
have hints of a new band / isomer at higher I, K...
heavy mass neutron rich nuclei in
mass 180 region predicted to have
many very long lived isomers...
So we see problem is in making these isomers at highspin.
fusion evaporation reactions can't get us there...
A.T. Reed,
D.E.Appelbe,
S.L.King,
The University of Liverpool
C. Wheldon,
C. Purry,
C. Pearson,
P.H. Regan,
The University of Surrey
Australian National University
at Canberra
R. D'Alarcao,
E. Seabury
Location?
M.P. Carpenter,
R.V.F. Janssens,
T.L. Khoo,
G. Hackman,
P. Reiter
D. Nissius
Argonne National Laboratory