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

■

■

*

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)

■ ■

■

* *

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