* * TASCA in Small Image Mode Spectroscopy

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1 TAS ISpec TASCA in Small Image Mode Spectroscopy * * * * * Introducing the set up TASCA SIM settings Commissioning experiments Characteristics Future: Missing parts / preparations Experiments

2 Why TAS ISpec? A world unique set up! * Small image mode => compact focal plane * High segmentation => Si 192 strips α efficiency ~80% * 4+1 segmented Ge detectors γ efficiency > * Multi coincidence possibilities y position (mm) No alpha decays Isomer + decay spectroscopy (Coulex inverse kinematics?) (SHE Identification via X rays?) x position (mm)

3 The Experimental Set up Internal structure of TASISpec Set up for the tests 4 Single sided Si strip detectors 1 Double sided silicon strip detector 1 Ge cluster detector (7 crystals) 1 Ge clover detector (4 crystals) Intention; 4 Ge clover detectors in final configuration

4 The Experimental Set up External structure, forming the "tail" of TASCA CLUSTER CLOVER X8 "SHE" Beam DSSSD Chamber Ge detector Si detectors

5 Test Experiments Reactions August and October 2008 Pb ( Ca, 2n) No K isomer test / α γ(γ) test Pb ( Ca, 2n) No *} Fission test X Pu ( Ca, Xn) 114 Background test 64 Ni 64 Ni } Nd Ra Short lived isomer tests * + Sm Th α γ(γ) tests 64 Ni nat 224 * + Gd U Background tests 64 Ni * + Pr Fr Reduced electronics noise?!

6 TASCA SIM Settings Modifications from the nominal values Dipole Quad1 Quad2 253 No transmission Nominal ~17% "Optimal" ~28% Nominal "Optimal"

7 α energy Resolution Comparing the FWHM in the same DSSSD August Noise October Reduced noise 253 No 200 At Normalised Intensity FWHM = 65 kev Gated on E = kev γ FWHM = 30 kev (without cooling!!)

8 Alpha Efficiency In total 80% of the emitted alpha particles are detected α 253 No DSSSD: detects 50% of emitted alpha particles Intensity Fm X rays Box: 40% less statistics than in DSSSD => detects some 30% => Total alpha efficiency 80% Gamma Energy (kev)

9 Energy Threshold in Box Using a 207Bi source on the DSSSD dummy October Intensity 70 kev Rough calibration using conversion electron lines 570 kev γ ray 1064 kev γ ray K K L L Sum of all 128 strips! Energy (kev)

10 Intensity Detection of the Emitted γ rays Comparison between the clover and the cluster detector γ rays detected in the Cluster: ε 16.0% γ Fm X rays > ε > rays detected in the Clover: 5.5% Note: cables + connectors! => Total: ε > 40% Fm α 253 No Egamma (kev)

11 Comparison with Previous Results γ γ correlations in 253No α gated γ γ matrix 253 No α Energy (kev) Fm Energy (kev)

12 Comparison with Previous Results Gate on the kev transition γ γ correlations in 253No Internal conversion: α tot (150 kev) = 0.21 α tot ( kev) = 8.5 α 253 No 150 Intensity Fm Energy (kev)

13 August Event Times Time difference between two subsequent triggers All events Beam off 300 µ s (3.3 khz) Beam on Dead time = 100 µ s Time Time

14 October Event times Time difference between two subsequent triggers 150 Nd (stationary) 150Nd (wheel) All events Beam off 3.3 khz!! Beam on Time Time

15 Comparison with Previous Results A. Lopez Martens et al. Phys Rev C 74, (2006) α 253 No 144 h, 0.7 pna GABRIELA, Dubna Intensity Fm Fm X rays ~35h, 0.05pnA ~4500 α particles Gamma Energy (kev)

16 Comparison with Previous Results F.P. Hessberger, Eur. Phys. J. D 45, (2007). 100 K α,β (Fm) Intensity E γ (kev)

17 One Step Ahead... Final step towards a configuration for experiments 4 Ge Clover + 1 Cluster detectors in final configuration CLUSTER CLOVER

18 One Step Ahead... Final step towards a configuration for experiments 54 o 4 Ge Clover + 1 Cluster detectors in final configuration Rebuild power + gas outlets! Required: 4 Ge Clover holding structure at the TASCA focal plane! X8

19 Planned Experiments Pb ( Ca, 2n) No Caracterisation of the K isomer(s) (multi coincidences needed!) June July 2009; 10 days => No α Pu ( Mg, 5n) Sg Rf No ; 3 weeks => Sg Ra ( Ca, 4n) Hs Search for the K isomer 2010; 3 weeks + Parasitic beamtimes ~4 weeks 2009 ~4 weeks 2010 (Reactions depending on available beams) Example: 20x 34 24z Pb ( S, yn) Cf decay spectroscopy (2009)

20 Facing Target Difficulties Using 150 Nd target wheel and 139 La stationary target α spectra 150 Nd 211, 212 Normalised Intensity 201 At (2n) Ra (3n, 2n) 209, 210 Ra (5n, 4n) 200 At (3n) Energy (Arbitrary Units)

21 Comparison with Previous Results A. Lopez Martens et al. Phys Rev C 74, (2006) 253 No Egamma (kev) α Fm alpha energy

22 Silicon Detector Multiplicity 150 Using natural Gd + 5 microns Ti backing and Nd targets DSSSD (n side) α?? Box Multiplicity Energy

23 Silicon Detector Multiplicity Using natural Gd + 5 microns Ti backing and DSSSD (n side) 150 Nd targets?? Box # of fired strips on each DSSSD side < = 5 α Multiplicity Energy

Gamma spectroscopy in the fermium region at SHIP

Nuclear Structure Physics with Advanced Gamma- Detector Arrays, Padova June 10-12, 2013 Gamma spectroscopy in the fermium region at SHIP Stanislav Antalic Comenius University, Bratislava Collaboration