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DESPEC Report: NuSTAR Management Meeting 12 th July 2010 DeSPEC Project formally started April 2010. Full array of (~)36 LaBr 3 detectors and mechanical.

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Presentation on theme: "DESPEC Report: NuSTAR Management Meeting 12 th July 2010 DeSPEC Project formally started April 2010. Full array of (~)36 LaBr 3 detectors and mechanical."— Presentation transcript:

1 DESPEC Report: NuSTAR Management Meeting 12 th July 2010 DeSPEC Project formally started April 2010. Full array of (~)36 LaBr 3 detectors and mechanical holders to be used with AIDA in PreSPEC decay campaign (2013). Personnel Issues: –DESPEC PDRA (Brighton) advertised, deadline for applications 13 th July; PDRA to start Oct. 2010. –DESPEC PhD student (UWS) to start Oct. 2010 In-beam tests of different types of LaBr 3 detectors for evaluation ‘in-beam’ and with sources. 3 types of LaBr 3 detectors 2”x2”, 1.5”x1.5” and other ‘conical’ style detectors. –Experiment to test these in-beam in Bucharest June 2010. Analysis of in-beam data and MC simulations to be performed by PDRA Oct 2010 – Dec. 2011 –(source) tests with AIDA Oct 2010 – July 2011 –(Pre-SPEC Decay) meeting to discuss pan-European integration of LaBr 3 fast-timing detectors, to take place in Brighton 9-11 Jan 2011.

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4 To do (soon) LaBr 3 source tests with AIDA (Oct. 2010 – July 2011) Design of test holding structure for test detectors (Dec 2010 – April 2011) EDAQ design (June 2011 – March 2012)

5 Precision Measurement of the Lifetime of the I  =4 - Intruder State in 34 P Using Ge-LaBr 3 -LaBr 3 Fast-Timing Coincidences Experiment at the Bucharest Tandem 23 rd June – 2 nd July 2010 Surrey Uni., Brighton Uni. (UK) UGC-DAE Kolkata IFIN-HH Bucharest Uni. Notre Dame, Florida State Uni. (USA) Istanbul University (Turkey) Sofia (Bulgaria) KACST (Saudi Arabia)

6 Physics Motivation 4-4- 2305 Recent study of neutron-rich, N=19 nucleus 34 P identified low-lying I  =4 - state at E x =2305 keV. Spin and parity assigned on basis of  -ray DCO and polarization measurements. I  =4 - → 2 + transition can proceed by M2 and/or E3. Aim of experiment is to measure precision lifetime for 2305 keV state → obtain B(M2) and B(E3) values. Previous studies limit half-life to 0.3 ns < t 1/2 < 2.5ns Lifetime gives a direct comparison with sdfp-shell model calculations, i.e., including (intruder) negative parity (neutron) f 7/2 and p 3/2 orbitals.

7 Experiment 18 O Beam (from Li 18 O 2 mixture) 50 mg/cm 2 Ta 2 18 O 5 enriched target 36 MeV 18 O beam from Bucharest Tandem (typical beam current ~20 pnA) 34 P from pn evaporation channel (  ~5-10mb) Measure reaction gammas from array of 8 x HPGe and 7 x LaBr 3 detectors. Master gate, either (LaBr 3 ) 2 OR (HPGe) 3 for a valid event.

8 Populate near-yrast states in 34 P via 18 O( 18 O,pn) 34 P reaction. Total projection from 18 O+ 18 O reaction 34 MeV (from Chakrabarti et al.,) *

9 Measure reaction  rays using Bucharest array of 8 x co-axial HpGe (for 34 P channel selection) plus 7 x LaBr 3 scintilation detectors (for fast-timing). Gate on Ge measurement of 429 keV or 1876 keV transition to select 34 P ions. Selects these ions from other evap channels. 31 S (  n); 33 P(p2n), 33 S (2pn), 34 S (2p).

10 2” x 2” detectors; 1.5”x1.5” detectors and 2 x ‘conical’ LaBr 3 detectors… in-beam and source data taken ( 152 Eu, 60 Co, 56 Co)… analysis on going.

11 LaBr 3 energy spectrum in coincidence with the 1876 keV peak ( 34 P: 4 - →2 + ) in the germanium detectors. Lifetime of the I  =4 -, Ex=2305 keV state in 34 P. Time (TAC) difference spectrum between the 429 keV (2 + → 1 + ) & 1048 keV (5 - → 4 - ) transitions in 34 P, AND gated by the 1876 keV (4 - → 2 + ) in any of the HPGe detectors. 50 ps/ chan. T 1/2 ~1.5(1) ns Time difference spectra between 1968 and 968 keV transitions in 33 S gated by energies measured in the LaBr 3. ‘Fast’ transition shows prompt response function by comparison. T.Alharbi, N. Marginean, P.H. Regan et al., Surrey, Bucharest, Brighton, Notre Dame, Florida State, Sofia, Istanbul, Koolkata, KACST collaboration.

12 IFIN-HH Bucharest (Romania), Surrey Uni., Brighton Uni. (UK), UGC-DAE Kolkata (India) Uni. Notre Dame, Florida State Uni. (USA), Istanbul University (Turkey), Sofia (Bulgaria), KACST (Saudi Arabia) collaboration.


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