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T he DIAMANT light-charged particle detector : Performance and plans for improvements

T he DIAMANT light-charged particle detector : Performance and plans for improvements. B.M. Nyakó (ATOMKI) Workshop on N W all at GANIL … 4- 5 Oct. 2007. HIL , Warsaw. Barna M. Nyakó.

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T he DIAMANT light-charged particle detector : Performance and plans for improvements

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  1. The DIAMANT light-charged particle detector: Performance and plans for improvements B.M. Nyakó (ATOMKI) Workshop on NWall at GANIL … 4-5Oct. 2007. HIL, Warsaw Barna M. Nyakó

  2. DIAMANTis a high-granularity, 4πlight charged-particledetector array [1] of CsI(Tl) scintillators, used as ancillary device in large gamma-ray spectrometers to discriminate xnγ&particle-xnγdata by vetoing or gating on emitted light charged particles.Signal processing:realized in VXI standard [2].Contact persons: B.M. Nyakóa, J.N. Scheurerba) Institute of Nuclear Research, (ATOMKI), Debrecen, Hungary; nyako@atomki.hub) CENBG,CRNS-IN2P3-Université de Bordeaux I, Gradignan, France; scheurer@cenbg.in2p3.frReferences 1. J.N. Scheurer et al. Nucl. Instr. and Meth. A 385 (1997) 501. 2. J.Gál et al. Nucl. Instr. and Meth. A 516 (2004) 502. The DIAMANT collaborationCENBG (Bordeaux) – ATOMKI (Debrecen) – University of NapoliJ.N. Scheurer et al. B.M. Nyakó et al. G. la Rana et al. Recently extended by: iThemba LABS (Cape Town)S.M. Mullins et al.

  3. The features of the DIAMANT array: Detectors:84 pcs 3mm CsI(Tl) scintillators with photodiode readout; 76 pcs square-shaped (14.5 mm) 8 pcs triangle-shape (29 mm) special wrapping technique: >80% light-collection efficiency;-energy resolution: 2% (5.5 MeV) Geometry Rhombicuboctahedron: flexible PCB forward wall(s): 3x3 or 5x5detectors Efficiency geometrical: ~ 90% of 4 detection of protons: > 70% detection of alphas:50% High granularitydeduce particle multiplicity; Doppler-correction of gammas Electronics: in-vacuum preamplifiers; VXI signal processing DIAMANT on service stand:the flexi-board arrangement The Octal Particle DiscriminatorVXI Card

  4. Example spectra of a CsI detector PID-vs-E Energy (E) Protons Alphas PID Time Output data from the VXI card Gating on individual (1D) or combined (2D) spectra of these data enables the - rejection of random events - selection of reaction channels - enhancement of gammas with special conditions Putting 1D gates on the • Time: eliminates part of the random coincidences • PID: improves channel selection Putting 2D gates on • PID-vs-Time: Further cleaning of particle-gamma coincidences from randoms; channel selection • PID-vs-E: Improved selection of gammas in coincidence with protons or alphas

  5. Exp-# Spokesperson(s) Date Beam/Target Detectors Status (MEV/mgcm-2)Exp-# Spokesperson(s) Date Beam/Target Detectors Status (MEV/mgcm-2) E404S P.J.Nolan Jun. 2002 76Kr/58Ni EXG + DIAMANT Resubmit+N.Redon (320/1.1) E404aS “ Oct. 2004 (328/1.1) EXG + DIAMANT Conf.,Thesis +VAMOS------------------------------------------------------------------------------------------------------------------------------------------------Commission B.M.Nyakó Oct. 2005 EXG+ DIAMANT +J.N.Scheurer + n-Wall E498S S. Williams Oct. 2005 18Ne/24Mg EXG + DIAMANT Not analysed (60/1) + n-Wall E482 A.Gadea Nov. 2005 36Ar/24Mg+Zr EXG + DIAMANT Oxigen (?)+S.Lenzi, (85/0.5+8) + n-Wall Resubmitted E451 B. Cederwall Nov. 2005 36Ar/58Ni EXG + DIAMANT Report by (111/6) + n-Wall K.Andgren ------------------------------------------------------------------------------------------------------------------------------------------------E505 G.de Angelis May 2006 36Ar/40Ca EXG + DIAMANT (No info) + n-Wall E514 M. Palacz Jun. 2006 58Ni/54Fe EXG + DIAMANT In progress +J.Nyberg (240/8) + n-Wall trigger probl's Summary of EXOGAM experiments using DIAMANT at GANIL

  6. DIAMANT early implementations: exp.s E404S, E404aS Physics motivation:Identification of -rays in nuclei around the drip-line nucleus 130Sm: probing the maximally deformed light rare-earth region • The 2+ energy of 130Sm, inferred to be 121 keV from fine structure in the ground-state proton decay of 131Eu, predicts a large moment of inertia and hence large quadrupole (prolate) deformation for this exotic nucleus • The nucleus 130Sm is thus an ideal candidate to assess the feasibility of gamma-ray spectroscopy of exotic nuclei produced with radioactive ion beams of SPIRAL using state-of-the-art detector systems • A pioneering experiment for EXOGAM using the DIAMANT ancillary detector; Difficulty: low-ray energy to be identified - Need for special detector arrangment. Experimental details • Target:1.1 mg/cm2 of 58Ni; • Beam: Radioactive 76Kr ions (t1/2 = 14.8 h) of intensity ~5-8 x 105particles per secondand energy ~4.5 MeV/u • First Expt:‘EXOGAM’ (6 segmented Clover detectors + 2 small Clover detectors) +DIAMANT(56 CsI detectors: 90°–ring + FW) • Second Expt: ‘EXOGAM’ (11 segmented Clovers) +DIAMANT(48 CsI detectors) +VAMOS From Nadine Redon

  7. Early Implementation-1:[5x5 forward wall + 90°-ring of 32 CsI]; beam EXOGAM+DIAMANT setup with VAMOS:Clovers @ 90° and backward angles Early Implementation-2:Sketch of the 'forward-only' version(to minimize -absorption) DIAMANT early implementations in EXOGAM

  8. DIAMANTspectrum Condition : at least 3p Condition : at least 1 no condition Nadine Redon: GANIL Oct. 2005

  9. Physics motivations of the NWall + DIAMANT campaigns: E498S High Spin States in the Tz=-3/2 Nucleus 37Ca – Mirror Symmetry at the(S.W) Largest Values of Isospin; 18Ne(60MeV) 1 mg/cm2 24Mg target; DIAMANT: selective device E482 Mirror Energy Differences in the A=58 T=1 mass triplet and Charge(A.G) Symmetry Breaking terms in the nuclear effective interaction above 56Ni;36Ar(85MeV) 0.5 mg/cm2 24Mg target on 90Zr backing, 4pnA Problem: Oxigen build-up in target; DIAMANT: rejective device E505 Electromagnetic decay properties of the Tz=±1/2 A=67 and 71 mirror pairs:(GdA) A test for isospin mixing and for pn pairing; DIAMANT: selective device E514 Neutron Single Particle Energies with Respect to 100Sn and Z=50 Core(M.P) Excitations by Investigating Excited States in 103Sn;58Ni(240 MeV) 8 mg/cm2 54Fe target, 1.7 pnA Problem: backing, trigger conditions; DIAMANT: selective device E451 Search for T=0 pairing and a new coupling scheme in 92Pd and 88Ru(B.C) 36Ar(111 MeV) 6 mg/cm2 58Ni target, 5 pnA Problem: Efficiency; (To be reported next.) DIAMANT: selective device

  10. beam Target Loader DIAMANT mechanics in preparation for the NWall + DIAMANT campaign. DIAMANT „fuller” configuration for EXOGAM + NWall experiments with stable and radioactive beams (Oct.-Dec. 2005, May-June 2006) Radioactive beams: two quad detector modules had to be removed to allow the NBI target loader pass through; This “fuller” configuration (Geom. Eff.: ~82 %) used for Stable beams

  11. High beam intesity, targets sim. PID-vs-E for the same detector Absorbent problem Ta Al High beam intesity, targets sim. PID-vs-E for the same detector Absorbent problem Ta Al Indicate improper Discrimination modeMixed vs Ball. Def. PID-vs-Time Example spectra for DIAMANT performance E482: ~ OK (~all worked) E514: Problems with backward part Comments on setup the VXI: check 2D spectra for correct operation!

  12. Good charged particle selection p 2α 2p  1α1p Energy 1α 1n Example spectra for DIAMANT performance (E482,E514) Good channel selection, but reducedefficiency for DIAMANT (Marcin’s exp.) Good Time resolution (with loss in statist.)

  13. Experimental observations during NWall campaigns Performance of the CsI detectors: thanks to Gábor Kalinka (labor), Giovanni La Rana (finance) Excellent: with proper absorber (even with high-intensity beams) Bad if absorbers are not sufficient for killing scattered ions/electrons DIAMANT must be protected from direct beam --> beam profile monitoring Performace of the electronics: thanks to János Gál & József Molnár Preamps: Excellent in spite of 'severe' conditions VXI: very reliable with controlled temperatureOne card is unstable - need testing Overall Performance: goodNeed for standard procedures to improve reliability, ease of data analysis

  14. Plans for improvements Aim: Enhance the performance of DIAMANT byoptimizing itsfeatures for furture Ge-detector arrays intended for nuclear structure studies with high intensity stable and radioactive beams of SPIRAL-2 Known Problems: A. Troublesome installation of CsI detectors in DIAMANT chamber B. CsI calibration, Target loading vs. efficiency, Vacuum feed-through C. Maintenance of the DIAMANT VXI cards is not obvious D. Limitations due to -absorption forE < 200 keV; CsI(Tl), PAs, cables Future Improvements: E. Test the applicability of Avalange PD-s for CsI-s in DIAMANT F. The CsI electronics has to be compatible with next-generation DAQ systems G. Position sensitive detector setups?

  15. The flexi board equipped with CsI + Ta-abs.;Rigid but versatile geometry The flexi board on support stand, ready for installation Very tight arrangement Solving Problems – ad A. Troublesome installation of CsI detectors:Compact geometry – to fit DIAMANT chamber inside EXOGAM configurations A and/or B The (relatively) EASY bits: and the DIFFICULT bits:

  16. Measured In-beam in ATOMKI Solving Problems - ad B: CsI calibration: Doppler correction, reaction mech. studies, etc. In-beam, with α-sources Problems: In-beam - needs beam-time, cost Sources: needs 232U or 228Thα-sources on target loaderγ-sources in target position (needs action from GANIL)

  17. Based on comparative α and γ calibrations: [D. Horn et al. NIM A420(1992)273] Light yield vs E: Solving Problems - ad B ctnd:

  18. Vacuum feed-through for glued ribbon cables PCB feed-throughs for DIAMANT on the AFRODITE chamber (iThema LABS, SA) Target loader for radioactve beams Alternative target holder for stable beams: Enables the use of complete geometry Need for beam collimation New opening of the chamber - easy handling New inside connectors and feed-throughs (SA experience) Solving Problems - ad B (ctnd): Target loading vs. efficiency.

  19. The VXI test-bench at GANIL Need for dedicated slot(s) compatible with DIAMANT VXI cards(Solved!) Solving Problems - ad C: VXI cards for DIAMANT need low temp. (22C°) Overheating happened in early exp.-s Few VXI channels developed permanent faults, some recovered One card has problems, needs fixing: Maintenance of the DIAMANT VXI cards: Ageing: > 10-year old technology; Obsolate parts/circuitries (GIR expertsleft the field, etc.); New VXI test-bench in GANIL -now compatible with CsI-VXI cards Personnal's help very much appreciated !

  20. Gamma-efficiency measured for EUROBALL + DIAMANT installed Hamamatsu S8664 ser. short wavelength type APD: 10x10mm2 Solving Problems – ad D: -absorption: caused mainly by CsI(Tl) + PAs, cables DIAMANT: Well suited for higher-energy -spectr. In special configurations (cf. E404S) absorption can be minimized Aims: minimize material, make room for handling, improve low-energy respons of the system Solution: Use of APD instead of pin-PD on CsI-s Transition to Perspectives! Expected advantages of using avalange photodiodes: 1. Higher light collection efficiency, large gain, signal/noise, --> improved particle discr. low-energy detection 2. Simpler PA arragement may be sufficient --> easier handling Plans for feasibility studies of using APD-s instead of pin-PD-s (EXOGAM-2 FP7 ??G.d F.)

  21. Hamamatsu S8664-10-10 Coincidence spectroscopy with PAD+CsI(Tl) can be done (?) Future Improvements - ad E. Properties of short wavelength type APD-s: good spectral response for CsI lighthigh quantum efficiency low dark current at Vbd (Vopt~ 350V)gain ~ 50 (T=20 C°) Disadvantages: Needs higher Voltage PS (opt. ~350 V) Gain is temperature dependent --> stabilisation APD with CsI(Tl): Excellent resolution for X-rays, low-energy -s[J.Kataoka et al. NIM A541(2005)398] --> use of DIAMANT as gamma-array for L.E. -s Ge-CsI coinc. time resolutions with DIAMANT [J.Gál et al. NIM A516 (2004) 502]

  22. Block scheme of proposed DAQ module Block scheme of miniPET2 DAQ module PSPMT Analog frontend MEMEC miniModule Bicron LYSO Prelude P420 24x24 1.9x1.9x12 mm3 MEMEC miniModule with Gigabit Ethernet Fast preamp Fast preamp Fast ADC FPGA Xilinx V4 FX12 C PowerPC LVDS Base line restoration F I F O Quad CsI module X+ Ethernet 10/100/1000 BaseT Pulse recognition X- Time stamp Y+ Energy calculation Y- HW M A C P H Y Hamamatsu H9500 PMT Local clock and/or Optical Module To be developed at ATOMKI: IP core - managing PID, Energy,etc. from digitalized signals in the Xilinx Virtex-4 FPGA HV Analog Devices AD9229-65 CsI Analog frontend Future Improvements - ad F: Plans for Upgrading: Digital Signal Processing for the CsI electronics for compatibility with next-generation gamma-arrays & DAQ systems The ATOMKI solution: 4-channel DAQ module developed for miniPET

  23. DSSSD 6Li(3He,t)6Be at 50 MeV 3He 4He CsI(Tl) The AFRODITE chamber equipped with60x60x0.3 mm3 SiDSSSD +2x2 arrays of 30x30x3 mm3CsI(Tl)+ Si pin-PD(P.Papka's curtesy) Example ΔE vs E spectrum produced by the DSSSD + CsI(Tl) arrays on the left Future Improvements: position sensitiveΔE-E particle discrimination In iThemba LABS DSSSD + CsI(Tl) arrayshave been used (in collaboration with ATOMKI)

  24. Summary of Perspectives and Future Developments of DIAMANT Short-range plans: Continue nuclear structure studies with EXOGAM using the stable and high-intensity radioactive beams available at GANIL: We propose DIAMANT for the nuclear spectroscopy community for studying nuclei for E > 200 keV. We plan to use it also with AFRODITE (TLABS, SA) and even to test it with the demonstrator version of the future AGATA array. With the technical developments outlined, there is hope for a succesful continuation! Long(er)-range plans: Develop a prototype CsI+APD detector and dedicated Preamplifier: (Plan)Test its applicability for low-energy coincidence spectroscopy Use Digital Signal Processing to replace the present VXI electronics (Needs financing!)for compatibility with EXOGAM-2 and AGATA Options: Use the 4-channel module under development in ATOMKI (Plan within EXOGAM-2)Dedicated Xilinx programs to be developed for CsI detector signals at ATOMKI; Use the circuitry under development for the Ge detectors of AGATA/GRETA [I.H. Lazarus et al, The GRT4 Pulse Processing Card ...., 2003]

  25. Need helpfrom physics groups to realize the planned Future Developments of DIAMANT List of volunteers: Form of contribution: To be completed!

  26. Thanks Members of the DIAMANT Collaboration: J.N. Scheurer et al1, G. La Rana et al2, J. Gál3, G. Hegyesi3, G. Kalinka3, J. Molnár3, B.M. Nyakó3, K. Juhász4A. Algora3, Zs. Dombrádi3, J. Timár3, L. Zolnai3 1CENBG, CRNS-IN2P3-Université de Bordeaux I, Gradignan Cedex, France2Dipartimento di Fisica, Universita di Napoli and INFN, Napoli, Italy3Institute of Nuclear Research, (ATOMKI), Debrecen, Hungary4Faculty of Informatics, University of Debrecen, Debrecen, Hungary& To all colleaguesof the many physics groups from different EU and outside laboratorieswho provided material about the status of data analysis and results of experiments

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