VISION ON DETECTORS

1. VISION ON DETECTORS Subhasis Chattopadhyay VECC, Kolkata V. Balagi BARC, Mumbai

2. Detectors in DAE:- Present status Detectors are being developed and used from the inception for detecting particles ranging from thermal neutrons to cosmic rays Neutrons, photons,charged particles (light or heavy), muons, neutrinos… Underground to nuclear physics labs, India, Europe, USA Nuclear physics, Solid State Physics, High energy physics, Medical diagonesis Special areas of interest for DAE Reactor safety and control Health physics instrumentation Basic research Based on this bright present we built our vision for luminous future

3. Detectors for tomorrow • Discussion based on: • Gross material properties of the media • Solid State Detectors • Gas Detectors • Scintillators and special detectors • R&D Continues to improve any or all of these areas. • Vision on detector development: • Improvement by newer detector materials/ technique. • New uses of the detectors for the society.

4. Solid State Detectors Various types of solid state detectors are used: Surface Barrier Si, Si(Li), HPGe, Si-pad, Si-strip, CCD based Handling Si technology for making detectors is itself a challenge • Achievements so far: • Low energy to URHIC, X-ray to high-energy charged particles • Si-strip detectors (1000 modules) for CMS experiment at CERN • Industrial participation BEL, Bangalore Proposals for future (one step ahead): Nuclear physics: Large BARC charged particle array (108 modules) High Energy Physics: Inner tracking with compact double sided Si-Microstrip. CBM@GSI (big challenge next 10-15 yrs). SAXS/WAXS: CCD camera for study of anisotropy in materials.

5. Solid State Detectors:- New materials CVD Diamond and Silicon-Carbide: (Radiation hard, Fast, Low noise, Rugged) CVD technique is tested at various labs in DAE Applications: Inner tracking in HEP Experiment, Reactor in-core flux monitoring, Medical Imaging SiC: Wide dynamic range, high temp. operation (To be developed) Si-pixel detector with amorphous Si (Pixel detectors are to be used in ALICE) Challenges ahead: Deposition of amorphous silicon on ASIC readout: new technology for pixel sensors (low cost, radiation hardness, thin films) Technological issues: Deposition of high quality (low defects) thin film. Applications: Medical Imaging, HEP Experiment.

6. Gas Detectors • Achievement so far: • High granularity gas proportional array • 100,000 cells (STAR experiment, BNL) • 250,000 cells (ALICE experiment, CERN) • Large area position sensitive pad chambers • (ALICE experiment, CERN) • Experience in underground experiments with gas detector. • (6000 proportional counter built) • Silver proportional counter: Pulse neutron flux monitoring • Proposals for future: • Tissue equivalent ion chambers: Total REM dose for X-rays and neutrons • Large area detectors • Multi-wire proportional chamber(MWPC) • Microstrip detector • Resistive plate chamber(RPC) • Gas Electron Multiplier (GEM) based detector

7. Focus Areas SANS/SAXS/WAXS Less sample scanning time, Solve parallax problem using curvilinear MWPC Microstrip Built in BARC INO: Neutrino observatory: Fast, good position resolution detector (RPC) • RPC dimension: 3m X 2m • No of chambers: 11K • Eff > 90% achieved Rigorous R&D worldwide Used in One HEP experiment. Pos res: 57micron, timing: 12nsec GEM: Wireless, flexible geometry, fast

8. Special detectors • TLFC configuration: 233U fission counters (up to 1cps/nv) • LEU fission counters (up to 3cps/nv) • Al2O3 based phosphor, KMgF3:Ce3+, SiO2:Cu, AlN, Dosimetry for gamma, fast and thermal neutrons • Gamma compensated Pt-Bi SPNDs :Overcomes anomalous behaviour of Pt SPNDs • Inconel SPNDs: Fast, low burn-up, long life. • Coiled detectors for future reactor • applications to be developed • Bubble detector: Personal dosimeter, • Measurement of pulsed neutrons, • On-line neutron area monitor

9. Discussions: detector vision Two clear areas emerge from DAE perspective: Radiation monitoring: Reactor program (with very stringent specifications) Beam monitoring and other diagnostics (accelerators) Materials study (material research is a thrust area in DAE) Plasma monitor  reduces import component significantly (e.g. Si), Industry collaboration is crucial. Quest of knowledge (NP, SSP, HEP, Astrophysics): We started with smallest scale:next decades will see DAE participating as a core member in these experimental program. INO will be project of next decade. A dedicated detector research facility (institute?) for DAE need alone. Next decade should see detectors for DAE from DAE, given the strong base we have, not a distant dream

10. Detector Vision: need of the society 9 keV absorption radiographyusing GEM Common theme: need of the society. Medical diagonesis. X-Ray imaging: GEM, a-Si-films with scintillators, PSDs . PET: RPC 2-D Dosimetry: GEM, RPC. Precision radiography setup using Si. Worldwide in large accelerator centres dedicated facilities are being built for development of detectors for medical applications eg. Medpix@CERN. We must have dedicated facility for R&D on Detectors for medical applications.

11. “ My very modest contribution to physics has been in the art of weaving in space thin wire detecting the whisper of nearby flying charged particles produced in high-energy nuclear collisions. It is easy for computers to transform these whispers into a symphony understandable to physicists. But the whispers can also be produced by radiations widely used in biology or in medicine,such as electrons from radioactive elements or X-rays. In this last case it is possible to reduce,by a large factor, the doses of radiations inflicted on the patients.” Georges Charpak, Banquet speech, Nobel Academy (1992)