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New gas detectors for the PRISMA spectrometer focal plane

M. Labiche - STFC Daresbury Laboratory. New gas detectors for the PRISMA spectrometer focal plane. New PPAC (Legnaro – Padova – Bucharest – Zagreb) & Large Secondary e - Detector (Se - D) (Manchester-Daresbury-Paisley- Legnaro). JRA6: INstrumentation for TAGging (INTAG - task4).

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New gas detectors for the PRISMA spectrometer focal plane

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  1. M. Labiche - STFC Daresbury Laboratory New gas detectors for the PRISMA spectrometer focal plane New PPAC (Legnaro – Padova – Bucharest – Zagreb) & Large Secondary e- Detector (Se-D) (Manchester-Daresbury-Paisley- Legnaro) JRA6: INstrumentation for TAGging (INTAG - task4) GANIL 02/10/2008

  2. The large acceptance tracking Magnetic Spectrometer Q-D:PRISMA W = 80 msr DZ/Z  1/60 (Measured) DA/A  1/190 (Measured) TOF Energy acceptance ±20% Br = 1.2 T.m beam MCP Start Detector X,Y & TI MWPPAC Detector 10 sect. X,Y & TF Ionisation Chamber 10x4 sect. DE - E GANIL 02/10/2008

  3. Results from PRISMAZ discrimination 40Ar+208Pb 450 MeV 70Zn+238U 450 MeV 96Zr+124Sn 575 MeV 136Xe+208Pb 950 MeV DE/E < 2% DZ/Z ~ 1/60 for Z=20 Z=30 Z=18 Z=17 PIAVE+ALPI Z=40 Z=54 Energy [arb. units] 3 Courtesy of E. Fioretto - LNL GANIL 02/10/2008

  4. FWHM/centroid≈1/160 Results from PRISMAMass resolution A=36 40Ar+208Pb Z=16 Yield of S isotopes Counts from P. Mason 96Zr+124Sn Z=38 Mass=92 Mass [amu] Counts FWHM/centroid ≈1/200 Yield of Sr isotopes Mass [amu] 4 Courtesy of E. Fioretto - LNL GANIL 02/10/2008

  5. New Focal Plane Detectors : Why? Mass resolution (DA/A) Atomic number Efficiency and mass resolution Efficiency Mass separation (1/A) 40Ar 96Zr Attenuation of the anodic signals produced by the delay lines Large energy straggling for slow moving heavy ions due to the detector windows New PPACs Se-D 5 GANIL 02/10/2008

  6. New PPACs for light ions 1.5 mm Mylar cathode +2x20 mg/cm2 Al 10 mm 200 20 mm 0.0005 15 cm 10 mm diameter Au plated Tungsten wires since July 2006 100 cm M.J06.4.2 a ~ 2.8 SE FF (A ~ 120 amu; E ~ 90 MeV)  ~ 200 SE 6 GANIL 02/10/2008

  7. Results with a source 241Am 10 ns Cathode Cathode X anode HV tests Filling gas : C4H10 Working pressure : 4 - 12 hPa Max HV (all configurations) ~ 410 - 600 V since July 2007 • Tests with a particles from a 241Am source • Rise-time • Charge calibration • Gas gain (>103) M.J06.4.3 Pulse height Cathode: 50 – 250 mV @ 600 V Anodes: 15 – 120 mV @ 600 V 50 mV/div 20 mV/div No signal at all with previous PPAC 7 GANIL 02/10/2008

  8. In-beam commissioning : How? START detector MCP 6x4 cm2 Beam MCP MCP 197Au Monitors 100x15 cm2 350 cm New PPAC • Time resolution • Position resolution • Efficiency vacuum vessel q = 90° Dq = 83° - 97°  6 msr • Beam time: 18th-19th Dec 2007 • Beams: • 32S at 150, 120, 100 and 90 MeV • 16O at 70 and 60 MeV • Target: 100 mg/cm2 Au M.J06.4.4 8 GANIL 02/10/2008

  9. In-beam commissioning : Results cathode X anode since Dec 2007 32S+197Au @ 100 MeV 32S+197Au @ 90 MeV 200 mV/div M.J06.4.4 50 mV/div max (Cathode/Anode) ~ 3 X Position spectrum Peak-to-valley ratio ~ 3.75 9 GANIL 02/10/2008

  10. In-beam commissioning : Results 32S+197Au @ 90 MeV Overall time resolution ~ 2 ns M.J06.4.4 including the energy straggling in the Au target, the kinematical broadening and the time resolution contribution of the MCP. 10 GANIL 02/10/2008

  11. Relative Efficiency: er=NX/NTOF OctaFluoroPropane Isobutane • C3F8 r~ 8.17x10-3 g/cm3 • C4H10  r~ 2.51x10-3 g/cm3 e~ 90% • 16O  40 MeV • 16O  130 MeV • 12C  45 MeV • 12C 14 MeV 11 GANIL 02/10/2008

  12. New Focal Plane Detectors : Why? Mass resolution (DA/A) Atomic number Efficiency and mass resolution Efficiency Mass separation (1/A) 40Ar 96Zr Large energy straggling for slow moving heavy ions due to the detector windows SED 12 GANIL 02/10/2008

  13. Working principle of Se-D A. Drouart et al., NIM. A477, 401 (2002) GANIL 02/10/2008

  14. SED small area prototype ASIC electronics LPMWPC Two Gas32 cards 80Se+12C @ 250 MeV X and Y positions: October 2007 14 GANIL 02/10/2008

  15. Preliminary design of the SeD 31 Gas16 boards for the X anode Se-D Emissive foil field rings Back plate omitted for clarity Coils 660.0 mm 220.0 mm Beam 1000.0 mm GANIL 02/10/2008

  16. 2nd prototype SeD PPAC readout module • Gassiplex 16 channel ASIC • Preamp – Shaping amp – Track and hold • Analog multiplexed output • 8 GAS16 boards – 128 PPAC wires – four connections. • 5Mhz readout clock – ~3us • 10 ADC samples per channel – average of four recorded. • PowerPC in the FPGA formats data • Ethernet link to MIDAS in PC – 1khz event rate. SeD - Electronics readout GANIL 02/10/2008

  17. Gas16 board developed @ DL Connections to the PPAC board Connections to the FADC board One Gas16 card (with 1x16 Gassiplex ASICs per card) to read 16 PPAC wires For each channel: Preamp + Shaping Amp + Track & hold • Existing ASICs chips : Gassiplex (Gas16) 3 cm 6 cm GANIL 02/10/2008

  18. Analogic output of the Gas16 bord: PPAC prototype @ DL Anodes X grounded (16 wires) + Cathode HV ~600V (trigger for Gas16 RO) + Anode Y grounded (16 wires) Gas16 boards GANIL 02/10/2008

  19. Flash ADCs -ASIC readout module Ethernet link to MIDAS Clock + readout control External trigger Eight input channels Analogue signal from the ASIC (time multiplexed 16 channels) GANIL 02/10/2008

  20. Summary • New PPAC for the PRISMA spectrometer have been assembled and tested with a particles; • two days of beam-time (18th-19th Dec, 2007) have been allocated by the LNL PAC for their in-beam commissioning; • Improved sensitivity and efficiencies for light charged nuclei; • A large SeD detector is being designed also for PRISMA by a UK collaboration • The electronics for individual wire readout has been developed @ Daresbury Laboratory and is currently being tested; • Next stage: couple several V4FADC boards together and synchronised via a metronome. GANIL 02/10/2008

  21. NOTHING after this slide GANIL 02/10/2008

  22. Tests of SeD detectors at GANIL Secondary electron detector beam 10x40 cm2 GANIL 02/10/2008

  23. Bench tests : Energy loss spectra D b + - + - - + - + d Landau distribution M.J06.4.3 23 Courtesy of E. Fioretto - LNL GANIL 02/10/2008 INTAG

  24. Bench tests : Charge calibration cathode X anode Y anode Canberra 2003BT Canberra 2020 Ampl PA ADC 2.2 pF Waveform generator M.J06.4.3 24 E. Fioretto - LNL GANIL 02/10/2008 INTAG

  25. Gas amplification Energy loss calculations SRIM 2008 M.J06.4.3 M.J06.4.3 25 Courtesy of E. Fioretto - LNL GANIL 02/10/2008

  26. PPAC Efficiencies Relative efficiency er of the X anodic plane with respect to the cathode for 16O at different energies has been estimated as follows : er = NX/NTOF Isobutane • C4H10  r~ 2.51x10-3 g/cm3 26 Courtesy of E. Fioretto - LNL GANIL 02/10/2008

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