Detector development and physics studies in high energy physics experiments Shashikant Dugad Department of High Energy Physics Review, 3-9 Jan 2008

Motivation DAE-DST Vision meeting (7-8 April 2006) –Need for core detector development Silicon Photomultiplier Water Cherenkov with WLS Readout GRAPES Muon/HCAL Imaging γ-ray Telescope MACE(BARC) ILC-HCAL INO-ECAL Space experiment? (ISRO) Tracking Detector Muon detector for GRAPES Calorimeter HCAL for GRAPES ECAL for INO? Many Other applications Experimental nuclear physics Imaging

Photo Devices Large gain (10 6 ) Cost prohibitive for large scale requirement Sensitive to magnetic field Occupies large volume Low gain (~100) solid state device Cost not as high as PMT In-sensitive to magnetic field Occupies small volume Small gain (~1000) solid state device Cost as high as PMT In-sensitive to magnetic field Occupies small volume PMT APD HPD Silicon Photomultiplier Low cost, high gain, fast timing device

SiPM APD operated above breakdown voltage – Geiger response mode Essentially a logical device – converted to photon counting by having large array of such diodes in small area APD SiPM

Typical design A micropixel of SiPM has a drift region at few micron epitaxy layer on low resistive P substrate. PN junction in epitaxy layer provides a depletion region with high electric field where Geiger mode discharge occurs with incoming photons. Electrical decoupling of the pixels provided by silicon resistive strips. Uniformity of the electric field within a pixel by n- guard rings or trench. All micropixels is connected by common Al strip to readout. Gain ~50 V working bias Low electronic noise -> Noise: Dark rate(~2 Mhz) is originated from thermally produced charge carriers Electrical decoupling to readout the signal Uniformity of the electric field 2 Drift region 1 N+ P+ Phos ~10 17 Boron ~10 15 Doping profile Electric field Geiger region E, (V/cm) x (um) Electric field distribution in epitaxy layer Topology of SiPM Hye-Young Lee

MIP With SiPM in HO-CMS

SiPM development plan SiPM characterization facility –In progress at Ooty with help from HCAL-CMS collaboration Packaging and assembly of the device –In progress with Bharat Electronics Limited (BEL) Device and Process Simulation, Fabrication –BEL, Banglore – Semiconductor Complex Limited, Chandigarh

MSOAmplifierSiPM Initial Setup for SiPM Study at Ooty

Characterization of CPTA-SiPM

Team BARCBARC –Chandratre etal. Expertise in device developmentExpertise in device development –Choudhary etal. Radiation testsRadiation tests ISROISRO –Discussions with Dr. Sreekumar in progress TIFRTIFR –Sudeshna Banerjee, S.R. Dugad, S.K. Gupta, P.K. Mohanty –Jagadeesan, A. Jain, S. Karthikeyan, K. Manjunath...

Water Cherenkov (WC) Detectors This technique is in use in detection of muons, electrons etc. (GRAPES Ooty, Kamioka, AUGER …) WC detector used at Ooty has good timing response but poor uniformity with no directinality Plans to make WC detector with good uniformity, timing and directionality –If we succeed then it can be used as an alternative to scintillators in large air shower array for measuring electromagnetic component –Muon detector with good angular resolution –Hadron/Electromagnetic Calorimeter for GRAPES/INO

Design Rectangular tube filled with distilled water doped with popop Several WLS fibers anchored along the length which carries photons to photo device Dimension: 50x4.6x4.6 cm 3 with 16 WLS fibers

Photoelectron yield of Water Cherenkov Detector

Timing Response

Summary Plans –Silicon Photomultiplier Characterization laboratory for SiPM Develop packaging and assembly line Fabricate SiPM –Water Cherenkov detector Optimize the performance Make prototype tracking detector with PMT/SiPM readout Expose it to ~GeV electron beam at INDUS-Indore to validate its calorimetric performance

Performance of SiPM Danilov etal.