Progress on the UK Contribution to FATIMA
FATIMA Workshop,
Grenoble, 19-20 July 2012
Paddy ReganCNRP
University of SurreyGuildford, GU2 7XH
UK Fast-Timing Array
• Part of discrete STFC funded NuSTAR Project (also included projects for R3B and HISPEC @ FAIR)
• People: – U. Brighton (Alison Bruce, Oliver Roberts [PDRA])– Surrey (Paddy Regan, Zsolt Podolyak, Christopher Townsley)– U. West of Scotland (John Smith, Kieran Mullholland [PhD]) – STFC Daresbury (Ian Lazarus-DAQ)– U. Manchester (David Cullen, Andy Smith - design of holding
structure).
• Task to design, build and commission ‘stand alone’ fast-timing gamma-ray array for use with AIDA at focal plane of (S)FRS at GSI/FAIR as part of DESPEC collaboration.
• Design (and budget) is for a modular, 30 (...or up to 36 later perhaps…) element array consisting of 1.5” x 2” LaBr3 cylinders.
What we have ordered (end of June 2012), co-ordinator, Dr. C. Townsley:
• 31 LaBr3 detectors (2” x 1.5” cylinders)• 19 to U. Brighton (Alison Bruce, Oliver Roberts)• 12 to U. Surrey (Regan, Podolyak, Townsley)• Cost £186,852
Initial Uses of (UK) Fatima Detectors(pre-DESPEC c.2017)
• 21 detectors to go RIKEN (3 x 7 element clusters) for use in EURICA array from ~Oct/Nov. 2012. – Use in (for example) 170Dy beta-decay proposal.
• ~8 detectors available for use with EXOGAM@ILL from early/mid 2013 for use in 235U(n,f) experimental campaign and/or Lohengrin experiments.
LaBr3 cylinder detectors to be coupled to (30) Hamamatsu R9779 PMTs • anode (timing) • dynode (energy) outputs
28 Hamamatsu PMTs with mu metal shield cases ordered May 2012 (£26,267)
Prototype AIDA Enclosure
• Prototype mechanical design• Based on 8cm x 8cm DSSSD
evaluate prior to design for 24cm x 8cm DSSSD• Compatible with RISING, TAS, 4 neutron detector
• 12x 8cm x 8cm DSSSDs 24x AIDA FEE cards
• 3072 channels
• Design complete
• Mechanical assembly in progress
In –beam test on the FRS approved (S390)Hope to be scheduled in the 2nd half of 2011
Possible Geometries (around AIDA)?
Hybrid ‘Crucifix’hybrid ‘Crucifix’(3 x 12 = 36 detectors)
2 x 3 design around AIDA stopper geometry.
36 cylinders 24 cylinders 30 cylinders
LaBr3 array simulated full energy peak efficiencies around AIDA
0
5
10
15
20
25
30
35
40
45
50
0 500 1000 1500 2000 2500 3000 3500 4000 4500
gamma-ray energy (keV)
Sin
gle
s f
ull
en
erg
y p
ea
k d
ete
cti
on
eff
icie
nc
y
Crucifix (36 hybrids) 3 x 2 (30 cylinders) 2 x 2 (24 clyinders)
LaBr3 array simulated full energy peak efficiencies around AIDA
1
10
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500
gamma-ray energy (keV)
Sin
gle
s fu
ll en
erg
y p
eak
det
ecti
on
eff
icie
ncy
Crucifix (36 hybrids) 3 x 2 (30 cylinders) 2 x 2 (24 clyinders)
simulations by O. Roberts, U. Brighton
Possible DAQ Solutions
• OPTION 1: Orthodox:– analogue, QDC for energy and TDCs for timing-
common AIDA/FRS start.)
• OPTION2: Mixed– XIA for energies and 10ns time stamp (ms
isomer spectroscopy); TDCs with common FRS/AIDA start for ns LaBr3 timing.
• OPTION 3: Fully digital:– Digitiser with FPGA (FATIMA ultimate solution)
LaBr3 PMTDelay
QDC V862
CFDV812
TDCV1290A
Energy
Time
Current
Gate
Stop
Common StartAIDA or Beam
V1495(2xA395A1x A395D)UserLogic
Clk sync
TS
For 30 channels:2x V812 CFD (16ch)2x N638 xlators (16ch)8x Phillips 794 G+D (4ch) 1x V1290A TDC (32ch)1x V862 QDC (32ch)1x A967 adapter30x N108 delay (2x64ns)1x v1495 with 2x A395A ECL inputs and 1 A395D NIM i/o1 VME crate + CPU2 NIM crates (N108s don’t need crates)
G+D794
anode
dynode
ECL-NIM726/N638
N108BNC
BNC
RobinsonNugentHD Flat
RobinsonNugentHD Flat
Diff ECLX16
Diff ECLsingle
LemoNIM
LemoNIM
Diff ECLX16
LemoAnalogue
LemoAnalogue
LemoAnalogue
Diff ECLX16 x2
RobinsonNugentHD Flat
Diff ECLX16 x2
A967adapter
Diff ECLX16 x2
Lemo-RNadapters
Option 1- Analogue QDC
LemoNIM
Optional-Seenotes
LaBr3 PMT
XIA DGF4
Energy & TS
Time
Current
Stop
For 30 channels:2x V812 CFD (16ch)1x V1290A TDC (32ch)8x DGF4 (4ch)1 VME crate and CPUI Camac crate PC with 9 USB ports to read DGF4s
anode
dynode
Option 2- Partially digital (XIA)
BNC
BNC
Diff ECLX16Lemo
Analogue
TDCV1290A
CommonStartAIDA or Beam
Diff ECLX16 x2
CFDV812
Clk & sync
SMA(XIA supply BNC adapter)
LaBr3 PMTTime, Energy & TS
Current
For 30 channels:8x V1751 (4ch)/STR3305 (4ch)1 VME crate and CPUOr8x Perseus + AD50001 uTCA crate and CPU
Digitiser with FPGAe.g. V1751, STR3305,or Perseus+AD5000
anode
dynode
Should we use dynode or anode?Dynode used for timing in analogue setup
Option 3- Fully digital (FATIMA based) Clk & sync
While we are waiting…
• A number of ‘test’ (and new physics) experiments at the Bucharest tandem using the mixed Ge-LaBr3 array (including 3 ‘UK’ LaBr3 dets).
• Results / Experiments include – I=4- intruder state half-life in 34P19 (f7/2 →d3/2 M2
single particle decay)– N=80 I=6+ half-lives (138Ce) – 186W(7Li,p) reactions, e.g., 188W (I=2+)– 208Pb(7Li,a2n) 209Bi (sp decays)
Expected, E1/2 dependence of FWHM on gamma-ray energy.
T.Alharbi et al., Applied Radiation and Isotopes, 70, 1337 (2012)
P.H. Regan Applied Radiation and Isotopes, 70 1125 (2012)
R(%)= [E/ E
Tests with 152Eu source (measure lifetime of I=2+ 121 keVlevel in 152Sm
T1/2=1.38 ns
18O(18O,pn)34P.~20 mbT1/2 (I=4-) = 2.0(1) nsMostly f7/2 →d3/2
M2 transition
{1876,429} =470(10)ps
{1048,429} T1/2=2.0(1)ns
34P19 (Simple) Nuclear Shell Model Configurations
20
1d5/2
2s1/2
1d3/2
1f7/2
20
1d5/2
2s1/2
1d3/2
1f7/2
I = 2+ [2s1/2 x (1d3/2)-1] I = 4- [2s1/2 x 1f7/2]
•Theoretical predictions suggest 2+ state based primarily on [2s1/2 x (1d3/2)-1] configuration and 4- state based primarily on [2s1/2 x 1f7/2] configuration.
•M2 decay can go via f7/2 → d3/2 (j=l=2) transition.
15 protons 19 neutrons 15 protons 19 neutrons
34P19 (Simple) Nuclear Shell Model Configurations
20
1d5/2
2s1/2
1d3/2
1f7/2
20
1d5/2
2s1/2
1d3/2
1f7/2
I = 2+ [2s1/2 x (1d3/2)-1] I = 4- [2s1/2 x 1f7/2]
•Theoretical predictions suggest 2+ state based primarily on [2s1/2 x (1d3/2)-1] configuration and 4- state based primarily on [2s1/2 x 1f7/2] configuration.
•M2 decay can go via f7/2 → d3/2 (j=l=2) transition.
15 protons 19 neutrons 15 protons 19 neutrons
34P19 (Simple) Nuclear Shell Model Configurations
20
1d5/2
2s1/2
1d3/2
1f7/2
I = 2+ [2s1/2 x (1d3/2)-1]
•Theoretical predictions suggest 2+ state based primarily on [2s1/2 x (1d3/2)-1] configuration and 4- state based primarily on [2s1/2 x 1f7/2] configuration.
•M2 decay can go via f7/2 → d3/2 (j=l=2) transition.
M2 s.p. transition
20
1d5/2
2s1/2
1d3/2
1f7/2
20
1d5/2
2s1/2
1d3/2
1f7/2
I = 2+ [1d3/2 x (2s1/2)-1] I = 4- [2s1/2 x 1f7/2]
•Theoretical predictions suggest 2+ state based primarily on [2s1/2 x (1d3/2)-1] configuration with some small admixture of [1d3/2 x (1s1/2)-1]
•4- state based primarily on [2s1/2 x 1f7/2] configuration.
•E3 can proceed by f7/2 → s1/2 (j=l=3 transition).
•Admixtures in 2+ and 4- states allow mixed M2/E3 transition.
15 protons 19 neutrons 15 protons 19 neutrons
T1/2=2ns{1048}{429}
‘Prompt’ T~480ps
{429}{1876}
P.J.Mason et al., Phys. Rev C85, 064303 (2012)
T1/2<2ps
138Ce80
{815,467}
{815,165}
…partial fusion reactions (low cross-sections)
Lifetime of first-excited 2+ in 188W
• 186W(7Li,p)188W, 33 MeV•Reaction mechanism is a
mix of incomplete fusion and low-energy transfer.
•~54 hours beam time•Analysed by P.J.R. Mason.
T. Shizuma et al. Eur. Phys. J. A30, 391 (2006)
296 keV gate (HPGe) 432 keV gate (HPGe)
Contaminants are 186Os
189Ir
Lifetime of first 2+ in 188W
•Estimate of 188W 2+ half-life from this short run gives unusual behaviour in B(E2).
Time difference 143-432 keVContaminated by 186Os [t1/2(2+) = 875(15) ps]
Fast-timing following - decay….
190Os levels from EC decay of 190Ir
Yamazaki et al., NPA131(1969) 169-179
P.J. Mason et al., 186W(7Li,2n)191Irperformed at Bucharest Tandem
P.J.Mason et al., private communication
T1/2 from t of187keV and (361 or 371)} = 375 (20) ps
190Os levels from EC decay of 190IrYamazaki et al., NPA131(1969) 169-179
….the (near) future• 21 detectors to EURICA
• 7/8 detectors for EXOGAM@ILL
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