Presentation on theme: "Nicola DAscenzo, Erika Garutti, Martin Göttlich University of Hamburg – DESY Hans-Christian Schultz-Coulon, Alexander Tadday University of Heidelberg Application."— Presentation transcript:
Nicola DAscenzo, Erika Garutti, Martin Göttlich University of Hamburg – DESY Hans-Christian Schultz-Coulon, Alexander Tadday University of Heidelberg Application of novel Silicon-based photo-detectors to calorimetry and medical physics calorimeter tracker MPPC
Electron Hole 1 Nov. 2007Erika Garutti - IEEE2/13 The Multi Pixels Photon Counter (from Hamamatsu) # Pixels (size mm 2 ) PiecesBiasDark Rate >0.5pixels Dark Rate > 1.5 pixels Gain (10^5) 400 (1x1)576 V kHz9-10 kHz (1x1)578 V50-60 kHz kHz (3x3)570 V MHz kHz Blue sensitive device: ideal for direct r/o of plastic scint. and crystals 1x1 mm 2 active area 3x3 mm 2 active area The MPPC is a multi-pixel avalanche photo-diode operated in Geiger mode PET application calorimetry application
Electron Hole 1 Nov. 2007Erika Garutti - IEEE3/13 MPPC characterization measured at university of Shinshu (see talk S. Uozumi, N41-4) intrinsic recovery time of MPPC ~ 4 ns response curve to a 50ns long light signal dynamic range artificially extended for long signals due to fast recovery time MPPC 1600pix has ~ 6000 effective pix. for 50ns long signal
Electron Hole 1 Nov. 2007Erika Garutti - IEEE4/13 Application in HEP calorimeters Task: readout of active layers of highly-segmented and granular calorimeter Single calorimeter cell readout with SiPM 3x3 cm 2 x 0.5 cm thick prototype active layer 100x100 cm 2 DATA CALICE test beam CERN 2007 Requirements to photo-detector: insensitive to B-field (~ 5T) couple to organic scintillator (green/blue) low noise (dark rate + cross talk above thresh.) ~ detection eff. for Minimum Ionizing Particles* >95% light yield for MIP ~10 pixels dynamic range ~ MIP * one MIP in 0.5 cm scintillator ~ ( · WLS eff ~ 200 on SiPM) ~8000 SiPM operated see talk by F. Sefkow, N13-5
Electron Hole Erika Garutti - IEEE5/13 Readout of plastic scintillators with MPPC study driven by calorimetry applications for a ILC detector R&D: direct r/o of scintillator tiles 3x3x0.5cm 3 Scintillator tile (Uniplast, Vladimir RU) + Green wavelength shifter fiber (Kurakay) Present status SiPM 1056 pixels (MEPHI/Pulsar, RU) green sensitive 3 cm MPPC directly coupled response to Ru 106 source MPPC 1600 px operation point light yield [pixels/MIP] MIP V bias - V breakdown [V] LY sufficient for calorimeter application but higher LY would allow thinner tiles (lower cost) w WLS fiber direct r/o
Electron Hole 1 Nov. 2007Erika Garutti - IEEE6/13 Cut at 3 KHz 400 px 1600 px Readout of plastic scintillators with MPPC MIP collection efficiency threshold at 1.5 pix dark rate < 3 kHz noise spectrum MIP spectrum MIP detection efficiency > 97% for all r/o combinations comparable with present status larger dynamic range than at present ILC requirement dark rate < 300 Hz MIP eff ~ 95% low but acceptable w WLS fiber direct r/o
Electron Hole 1 Nov. 2007Erika Garutti - IEEE7/13 Application in PET detectors reduction of background Task: identify back-to-back scattered 511 keV photons from e + e - annihilation suppress background and determine true line of response Background events remove Compton-scattered with good energy resolution remove combinatorial bg by ToF meas. t = 500 ps
Electron Hole 1 Nov. 2007Erika Garutti - IEEE8/13 Readout of scintillators crystals with MPPC study driven by possible PET applications * Lutetium OrthoSilicate from Heilger Crystals ** Lutetium Fine Silicate from Lebedev, Moskow 2 x scintillator crystals LSO*: 1x1x15 mm 3 3x3x15 mm 3 LFS**: 3x3x15 mm 3 emission: ~420 nm decay time: ~40 ns Teflon wrapping 2 x MPPC 1x1 mm 2, 400 pixels 3x3 mm 2, 3600 pixels coupled with optical grease Na 22 source due to high MPPT gain (7.5x10 5 ) no amplification needed simple readout energy integral on VME QDC (Lecroy 1182) time resolution measurement: 4 GHz Oscilloscope, 50 ps resolution (Textronix TDS7404B)
Electron Hole 1 Nov. 2007Erika Garutti - IEEE9/13 LSO and LFS similar performance (within syst. uncertainty of ~ ± 2%) Result comparable with typical value for LSO crystals + PMT is E/E ~ keV Readout of scintillators crystals with MPPC Energy resolution MPPC 400 LSO Crystal 1x1 mm 2 system 3x3 mm 2 systems MPPC 3600 ~ 8% for LSO negligibleblue sensitivity ! after 4 months of test E resolution ~ 13±2% degradation of MPPC package or crystal surface ?
Electron Hole 1 Nov. 2007Erika Garutti - IEEE10/13 Issue of MPPC saturation integral of 511 keV signal ~ 2000 p.e. ! but: signal width ~120 ns peak amplitude ~ 400 p.e. below saturation estimated at > pix. for 3600 pix. MPPC and 120 ns signal but MPPC response non-linear everywhere (see talk N18-2, K.C. Burr) 3600 pix. MPPC coupled to 3x3x15 mm 3 LSO crystal QDC spectrum scope signal
Electron Hole 1 Nov. 2007Erika Garutti - IEEE11/13 Readout of scintillators crystals with MPPC Time resolution Procedure for time resolution measurement: 0. store two waveforms from scope if amplitude > noise level (~ 2mV or ~10 pixels) 1.apply energy cut to exclude Compton background 2.define a timing threshold to measure time difference between signals t cut 2. two waveforms from the photon peak the voltage of the two MPPC is tuned to give same response to 511 keV N pe 1.
Electron Hole 1 Nov. 2007Erika Garutti - IEEE12/13 Time resolution: result N pe = ± 1 of photon peak ~10-15% of collected events used for lowest threshold FWHM ~ 650 ps limited by scope noise *no Jitter analysis package used for this analysis Background # events time difference [ns] 2 photon-peak amplitudes Compton background Photoelectric fix threshold discr. Constant fraction discr. threshold [pixels]
Electron Hole 1 Nov. 2007Erika Garutti - IEEE13/13 Conclusions MPPC 400 and 1600pix very good candidates for highly-granular calorimeter: - direct coupling to plastic scintillator - LY MIP ~ 7 (10) p.e. with direct coupling (WLS fiber mediated coupling) - satisfactory MIP detection efficiency with required noise cut MPPC 3600 pixels excellent performance for PET application: - E resolution comparable to PMT - t resolution < 650 ps (noise limited) next step: build 2 matrices of 6x6 MPPC with individual readout to test homogeneity, stability, reproducibility, calibration, multi-channel system 6x6 MPPC x6 LFS crystals 3x3x15 cm 3 we would like to thank Hamamatsu for providing the MPPC samples for this study