Detector development and physics studies in high energy physics experiments

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

2. Motivation • DAE-DST Vision meeting (7-8 April 2006) • Need for core detector development Water Cherenkov with WLS Readout Silicon Photomultiplier 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

3. Small gain (~1000) solid state device Cost as high as PMT In-sensitive to magnetic field Occupies small volume Photo Devices PMT APD HPD Large gain (106) 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 Silicon Photomultiplier Low cost, high gain, fast timing device

4. 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

5. Geiger region 106 to readout the signal Electrical decoupling E, (V/cm) Doping profile N+ 104 Electric field Drift region Phos ~1017 102 P+ Boron ~1015 0 2 1 Uniformity of the electric field x (um) Topology of SiPM Electric field distribution in epitaxy layer 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 ~106 @ ~50 V working bias • Low electronic noise • -> Noise: Dark rate(~2 Mhz) is originated from thermally produced charge carriers Hye-Young Lee

6. MIP With SiPM in HO-CMS

7. 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

8. SiPM Amplifier MSO Initial Setup for SiPM Study at Ooty

9. Characterization of CPTA-SiPM

10. Team • BARC • Chandratre etal. • Expertise in device development • Choudhary etal. • Radiation tests • ISRO • Discussions with Dr. Sreekumar in progress • TIFR • Sudeshna Banerjee, S.R. Dugad, S.K. Gupta, P.K. Mohanty • Jagadeesan, A. Jain, S. Karthikeyan, K. Manjunath ...

11. 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

12. 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 cm3 with 16 WLS fibers

13. Photoelectron yield of Water Cherenkov Detector

14. Timing Response

15. 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

16. Performance of SiPM • Danilov etal.