Giant Resonances in Exotic Nuclei Experimental Status and Perspectives
Nuclear structure and decay data in exotic nuclei - … · Nuclear structure and decay data in...
Transcript of Nuclear structure and decay data in exotic nuclei - … · Nuclear structure and decay data in...
Zsolt Podolyák
University of Surrey
Nuclear structure and decay data in exotic nuclei
production yields at FAIR
Exotic nuclei?
~2700 isotopes discovered, other ~3000 exist
M. Thoennessen, B.M. Sherril, Nature 473 (2011) 25
Fragmentation (spallation) reactions at relativistic energies:
abrasion ablation
multi-hole
state
σ (
mb
)
H. Alvarez-Pol et al., Phys. Rev. C 82, 041602(R) (2110)
titan.triumf.ca
Relative theoretical predictions of mass models for the Cs isotopes
Known masses
Models/theories have their limitations
Sn=0
How are the elements found in the Universe formed?
Rapid neutron capture process responsible for
the production of half of the elements heavier than iron
In flight fragmentation (and fission): separation and identification
Fragment Separator (GSI, Darmstadt, Germany)
Ge
Relativistic energy fragmentation: => heavy ions
Isomeric decay spectroscopy:
- decay correlated with the fragment
- very sensitive
192W setting
Identification
Identification of fragments
Fragmentation of 1 GeV/u 208Pb
Stopped Rising Array @ GSI: 15 x 7 element CLUSTERs
εγ =11% at 1.3 MeV, 20% at 550 keV, 35% at 100 keV
flight time ~300ns
beam
Passive stopper: For isomeric decays, T1/2< 1 ms
Isomeric states (from fragmentation)
208Hg,209Tl
N. Aldahan et al.,
PRC80,
061302(R) (2009).
Isomeric state RISING: isomeric decays S. Steer et al., Phys. Rev. C 84 (2011) 044313
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A. Gottardo et al. PRL109(2012)162502 210Hg: PLB 725 (2013)292
M.Reed et al., PRL 105 (2010) 172501, PRC 86 (2012) 054321 (ESR storage ring)
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5 cm x 5 cm DSSSD (16 strips by 16 strips = 256 pixels) 3 positions across focal plane, room for 3 detectors deep.
Active stopper: correlation between implantation and charged particle decay
R. K
um
ar e
t al
., N
IM A
598 (
2009)
754.
5 cm x 5 cm DSSSD (16 strips by 16 strips = 256 pixels) 3 positions across focal plane, room for 3 detectors deep.
Active stopper: correlation between implantation and charged particle decay
R. K
um
ar e
t al
., N
IM A
598 (
2009)
754.
Semi-logarithmic preamplifier
Beta decay
194Re
194Os
188Ta
188W 190W 192W
190Ta 192Ta
implanted
decay into
A.I. Morales et al., PRC 88 (2013) 014319
N. Alkhomashi et al., PRC80 (2009) 064308
T1/2: G.Benzoni et al., PLB 715 (2012) 293
N. Al-Dahan et al., PRC85 (2012) 034301
A.I. Morales et al., PRC 89 (2014) 014324
Zs. Podolyák et al., Phys. Lett. B 672 (2009) 116.
Internal charged particle decay
Internal gamma decay
205Au: three proton-hole nucleus
Gammas following beta decay
πh11/2-2 s1/2
-1
205Au
πh11/2-1 s1/2
-2
πd3/2-1 s1/2
-2
Orig. Mod.
(13/2-)
Basic Principles of the Fast Timing Method
• Experimental setup Digitizer: 4 GS/s sampling rate, 4 GHz bandwidth, 10-bit resolution, from Agilent Technologies (DC252HF)
Simple integration CR-RC pulse shaping Trapezoidal shaping
LaBr3:Ce detectors ( 5 % Cerium), Cylindrical (1.5"× 2") PMTs: H10570 from Hamamatsu, 1200 volt voltage
M. Nakhostin
0.00 0.05 0.10 0.15 0.20 0.25 0.30
200
220
240
260
280
300
320
340
360
380
FW
HM
(p
s)
CFD Fraction
Energy Gate 1100-1400 keV• Effect of CFD threshold
0 20 40 60 80 100
1
10
100
Co
un
ts
Time (Channel)
25 ps/ch
Digital : 239.22 ps (FWHM)
Analogue : 305 ps (FWHM)
• Digital time spectrum
CFD: 7 %
M. Nakhostin
HPGe LaBr3(Ce) Good energy Resolution And very fast (good timing)
34P
T1/2= 2.0(1) ns
P. J. R. Mason et al., Phys. Rev. C 85, 064303 (2012)
2 ns
207Tl studied at CERN (beta decay of 207Hg)
T. Stora, EURISOL town meeting, Oct. 2012
B. Jonson, O.B. Nielsen, J. Zylicz, CERN-81-09 (1981) (Proc. Int. Conf. Nuclei far from stability, Helsingor, Denmark. Vol.2 p.640 (1981))
207Hg beam
CERN/ISOLDE August 2014
207Tl interesting also because: is the final decay of the 4n+1 actinium decay chain which is ubiquitous in naturally occurring radiation, starting from the primordial radionuclide 235U. This decay could be used as an experimental monitor for enriched nuclear fuel . It has the potential to be used as a radiopharmaceutical tracer in the decay of the 4n+1 decay chain member 223Ra, which is now being used in as the RaCl2 chemical treatment for the palliative treatment of metastasized prostate cancers.
thanks