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The double-sided silicon strip detector with excellent position, energy and time resolution

The double-sided silicon strip detector with excellent position, energy and time resolution. Bachelorthesis by Eleonora Teresia Gregor. Rare ISotope INvestigation at GSI (RISING). decay studies with active stopper. spectroscopy at relativistic energies. scattering experiments

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The double-sided silicon strip detector with excellent position, energy and time resolution

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  1. The double-sided silicon strip detector with excellent position, energy and time resolution Bachelorthesis by Eleonora Teresia Gregor

  2. Rare ISotope INvestigation at GSI (RISING) decay studies with active stopper spectroscopy at relativistic energies scattering experiments with TOF measurement

  3. Introduction and Motivation – RISING experiments The DSSSD as an active stopper in decay experiments The detector model The electronics Testing the active stopper detectors The RISING-setup The DSSSD as a timing detector in scattering experiments The test experiment Testing the thin detector model Microchannel plate detectors The electronics Time resolution Testing the MFA-32 Summary and Outlook Content

  4. Radioactive ion beam production

  5. The FRagment Separator (FRS) The fragment separatorFRS

  6. Experimental Setup • 1 GeV/u U-238 beam • 2.5g/cms Be target • 105 HPGe crystals (15 clusters) • Efficiency: 9-14% • Active Stopper DSSSD Array

  7. RISING Implantation-Decay Detector • Heavy ion from FRS • Decays after a certain time, according to half-life • Emission of β-particle and prompt γ-rays • Correlation via position (x,y) of ion hit and β-particle γ β (ΔE signal) Animation: Berta Rubio

  8. DSSSD by Micron Semiconductor Ltd. 256 3*3mm2 pixels; active area of 5*5 cm2 W1(DS)-1000: Thickness: 1000 µm Depletion voltage: 180-200 V W1(DS)-40: Thickness: 40 µm Depletion voltage: 10 V Schematic drawing provided by Micron Semiconductor Ltd. The double-sided silicon strip detector

  9. Strip detectors M. Krammer: "Detektoren in der Hochenergiephysik"

  10. 207Bi energy spectrum The electronics for the active stopper Micron Semiconductor Nº Pixels: 256 Element Length: 49.5 mm Element width: 3.0 mm Active Area: 50x50 mm2 Thickness: 40 & 1000 µm MPR-32 Charge Sensitive Preamplifier 32 channels Sensitivity switch, factor 5 Bias voltage up to ±400V CAEN STM-16 16 channel NIM module shaper amplifier timing filter amplifier leading edge discriminator MRC-1 Remote controller via R-232 MHV-4High precision bias supply4 channelsCurrent warningVoltage up to ± 400V ADC V785AF 32 channels All pictures from datasheets provided by mesytec/CAEN

  11. The electronics for the active stopper

  12. K-conversion: 976 keV K-conversion: 482 keV L/M-conversion: 554-567 keV L/M-conversion: 1048-1061 keV 570 keV 1064 keV Testing with a 207Bi-source ΔE=1.6% ΔE=3.1% Transition Energies in 207Pb:

  13. Analysis Programme: Go4 Shaping time: 1µs or 2.5µs FWHM Long shaping time improved energy resolution by ~0.1-0.2% Setting thresholds just above the noise level Gain factor: 12.2 Mean energy resolutions: 15-19keV for front junction sides 18-21keV for rear ohmic sides From: NIM A598 (2009), 754 Testing with a 207Bi-source

  14. Hit in a single strip -> position resolution of 3mm Hit in two or more strips -> centroid of the energy distribution -> position resolution better than 3mm Position resolution of a DSSSD Strip multiplicity for front (left) and rear (right) side Multiplicity distribution over strip number relative to the center hit All from: NIM A598 (2009), 754

  15. The RISING-setup • S361: Shape evolution near 106Zr • S337: Structure of 132In populated in the β-decay of 132Cd: the νf7/2πg9/2-1 multiplet on the doubly magic 132Sn core. • S350: Moving along Z=82, beyond the doubly-magic 208Pb nucleus • 6 detectors in two rows of three • Active stopper vessel: 2 mm Pertinax covered with 20 µm pocalon carbon foil, measurement in dry nitrogen • Problem: measure both electrons (energy <1 MeV) and implanted particles (energy ≥ 1 GeV) • MPR-32 logarithmic pre-amplifiers: linear range of 2.5 or 10 MeV (70% of total range) and logarithmic range until 3 GeV

  16. Plastic scintillator Plastic scintillator Target DSSSD DSSSD CsI-detector Beam from FRS A, Z E~100MeV/u Be/Au tStart Energy loss ΔE Energy loss ΔE tStop x, y Residual Energy Eres Scattering experiments Germanium Cluster Detectors x, y • Fragmentation or Coulomb-excitation • Particle has to be identified again • Energy loss ~ Z2 • Total energy (Eres+ΔE) and speed yield mass • Time-of-flight measurement • Scattering angle (twice position) • Goal: Reduce number of detectors

  17. Plastic scintillator Target DSSSD DSSSD CsI-detector Beam from FRS A, Z E~100MeV/u Be/Au Energy loss ΔE Energy loss ΔE tStop x, y Residual Energy Eres Scattering experiments Germanium Cluster Detectors tStart x, y • Fragmentation or Coulomb-excitation • Particle has to be identified again • Energy loss ~ Z2 • Total energy (Eres+ΔE) and speed yield mass • Time-of-flight measurement • Scattering angle (twice position) • Goal: Reduce number of detectors

  18. Overview of the UNILAC-Experiment's Setup

  19. Energy resolution and calibration of the thin detector used for time measurement Mixed α-source: 239Pu, 241Am, 244Cm Am-Peak used to determine energy resolution No data from badly damaged strip Y1 Testing with a mixed α-source Pu-2395.245 MeV Am-2415.476 MeV ΔE=0.61% Cm-2445.902 MeV

  20. Entrance window (mylar foil); electrostatic mirror; position sensitive microchannel plate A particle passing the foil causes electrons to be emitted from it; which are diverted by the wire grid's electric field An entering electron hits the channel wall and creates additional electrons High voltages (2400 & 2500V) to attract the electrons Output signals have a low time jitter, but large random noise The microchannel plate detector Н. А. Кондратев

  21. The electronics for the UNILAC-Experiment

  22. Time difference between MCPs Time difference between both MCPs, gate on time-7, energy-8 Time resolution with two microchannel plate detectors • Using data collected over the whole MCP: • Reasons not to do this: • burn-like spots • different flight paths • Therefore: Time resolution with gates on single pixels of DSSSD • Weighted mean of 35 pixels:

  23. Signal from channel 2 (dark blue) and 3 (light blue) Time resolution with the silicon detector • Test with a new preamplifier and matching discriminator built by Wolfgang König • Cross talk between neighbouring strips is eliminated by an energy condition • Energy strips 12-15 covered • Multiple peaks in spectra over entire strip – charge carriers need time to migrate to the electrodes 9 2 10 6&7 3 11 8 Energy Strip 0&1 4&5 Difference between MCP1 and DSSSD for time strip 7 Signal from time strip 8 (dark blue) and 7 (light blue)

  24. Time difference between MCP 1 and DSSSD, gate on time-7, energy-2 Time resolution with the silicon detector • Data analysed pixel by pixel • Two time resolutions per strip (MCP1 – Si & MCP2 – Si) • Weighted mean of both: • Time resolutions vary between 26 and 186 ps • Mean of all pixels:

  25. Testing Mesytec's MFA-32 • 32 channel fast amplifier • optimised for high energy deposition: 100MeV to 2GeV • Requires positive inputs • 8 fast outputs, each the sum of four neighbouring channels • negative output • position internally coded In- and outputsides of MFA-32, from datasheet provided by Mesytec

  26. First test with 5.4MeV α-particles from 241Am Second test at X7 with 48Ca at 5.9MeV/u Energy signal (dark blue) and time signal (light blue) from 48Ca-ions Energy signal (yellow) and time signal (light blue) from α-particles Testing Mesytec's MFA-32

  27. Summary and Outlook • Position resolution: 3mm or better • Energy resolution: 1.8% for 1 MeV electrons and 0.6% for 5 MeV α-particles • Time resolution: Mean of 54ps with large variation • A future test will most likely reduce the number of detectors close to the target to one DSSSD for position, energy and time measurement

  28. H.Geissel et al., Nucl. Instrum. and Meth. B70 (1992) J. Simpson, Z. Phys. A358 (1997), 139 S. Pietri et al., Nucl. Instrum. and Meth. B261 (2007), 1079 H. J. Wollersheim et. al., Nucl. Instrum. and Meth. A537 (2005), 637 Zs. Podolyák et. al., Nucl. Instrum. and Meth. B266 (2008), 4589-4594 R. Kumar et al., Nucl. Instrum. and Meth. A598 (2009), 754 D. Rudolph et al., Technical Report, V1.2, June 2008 Knoll, Glenn F.: Radiation Detection and Measurement; John Wiley & Sons, Inc. Micron Semiconductor Ltd. http://www.micronsemiconductor.co.uk Mesytec http://www.mesytec.com CAEN http://www.caen.it/ GSI Analysis System Go4 http://www-win.gsi.de/go4/ Cern Data Analysis Framework ROOT http://root.cern.ch/ A. E. Antropov et. al, Nucl. Phys. Proc. Suppl. 78:416-421, 1999 Sources

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