Status of INO detector R&D B.Satyanarayana TIFR, Mumbai

2B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March INO detector R&D centres BARC, Mumbai BARC, Mumbai IITB, Mumbai IITB, Mumbai SINP & VECC, Kolkata SINP & VECC, Kolkata TIFR, Mumbai TIFR, Mumbai Summary

3B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March Gas mixing system

4B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March Setting up of a muon telescope

5B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March Spacers, nozzles and buttons

6B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March Bakelite RPC fabrication

7B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March Glass characterisation studies

8B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March Current status and future plan Problem of high dark currents with glass RPC Trying to make RPCs with bakelite sheets with and without linseed oil Will build glass RPCs also in parallel Assembling strip sized scintillator paddles for setting up telescope and to record efficiencies from single RPC strips

9B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March Status of RPC Lab at IITB Lab space obtained and setup Gas system will arrive early next week Electronic modules, power supplies, materials being procured Basic cosmic ray test setup exists A multi-gap RPC built 4 gaps with 375µm spacing 4 gaps with 375µm spacing 2mm float glass used 2mm float glass used Outer most surfaces coated with graphite Outer most surfaces coated with graphite

10B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March Work on bakelite chambers One Chinese chamber of a ft 2 in area, made using oil-less bakelite sheets, was studied Efficiency plateau of over 90% recorded, starting at high voltage of about 8KV, in streamer mode One chamber of a ft 2 in area, was built using Chinese bakelite sheets Efficiency plateau of over 92% recorded, starting at high voltage of about 9.2KV, in streamer mode One chamber of a ft 2 in area, was built using local bakelite sheets Chamber draws very high dark current Bulk resistivities of local bakelite varieties measured Superhylam (Coated with white melamine) Grade P-1001 (Coated with natural colour melamine). Resistivities of about 1-2  Ω-cm obtained

11B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March A sample of measurements

12B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March Long-term study of small chambers 2mm float glass from Japan Two chambers of one ft 2 in area Operated in avalanche mode R134a (C 2 F 4 H 2 ):Iso-butane::95.5%:4.5 by volume R134a (C 2 F 4 H 2 ):Iso-butane::95.5%:4.5 by volume Readout by a G-10 based pickup plate Preamp gain of 10  2 Combined efficiency over 93% In system for about 18 months Reasonably stable behaviour

13B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March Long term efficiency monitoring

14B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March Import of float glass sheets 100 sheets from Japan 1 m 2 in area 1 m 2 in area 2mm thick 2mm thick 200 sheets through Opera group, Italy 1 m 2 in area 1 m 2 in area 3mm thick 3mm thick Chamfered at the corners Chamfered at the corners Coated with resistive paint Coated with resistive paint

15B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March Current RPC development work Several small sized chambers built using the Japanese glass and are being tested; they seem to be doing well till now A couple of 1 m 2 chambers were also made and are under tests Multiple channel, low noise, high gain, high bandwidth amplification is a bottle neck Solutions using BARC discrete version boards, cascades, NIM packaged preamplifier don’t seem to work well Circuit board for cascaded HMC chips is being designed; will be used in prototype detector as well Some commercial fast chips are also being tried out

16B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March New RPC fabrication jig Need for uniform pressure on the glass sheets while being glued to the button spacers Till now using dead loads distributed through metal sheets or wooden boards Works fine for small chambers; but unsuitable for large area chambers A pneumatic jig developed to solve this problem Cover the RPC assembly with a polythene sheet to make a closed volume Cover the RPC assembly with a polythene sheet to make a closed volume Evacuate the volume using a vacuum pump in a closed loop till the epoxy sets in Evacuate the volume using a vacuum pump in a closed loop till the epoxy sets in Fabricated a few 1 m 2 chambers successfully

17B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March RPC mechanics Serves many purposes Good grounding, RF/EMI shielding Good grounding, RF/EMI shielding Uniform pressure for the entire RPC area Uniform pressure for the entire RPC area Facilitates uniform gas flow Facilitates uniform gas flow Mechanical rigidity and ease of handling Mechanical rigidity and ease of handling Provides elegant method to terminate HV, gas, low voltage power supplies and signals Provides elegant method to terminate HV, gas, low voltage power supplies and signals First prototype, housing discrete preamps inside was fabricated and being tested Improved version will be used for prototype chamber

18B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March Studies on resistive coating Consultancy by UDCT, Mumbai Preparation of paints by Nerolac, Mumbai Coating by Unicoats, Mumbai Optimisation studies, both in terms of the paint, as well as the application are in progress Application is still a manual process now Long term monitoring of surface resistivity as well as coat quality to be studied

19B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March Spacers, nozzles and buttons Material: Polycarbonate Fabricator: Ashwin Plastics, Mumbai Third and final iteration in progress

20B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March Development of pickup panels Using till now, pickup panels barrowed from Fermilab Foam sandwiched between two aluminum foils using heat lamination Foam sandwiched between two aluminum foils using heat lamination One foil segmented to form pickup strips One foil segmented to form pickup strips An Indian company (Multivac) was identified to produce these panels locally Many samples of different materials and geometry fabricated and tested for characteristic impedance of the strips, dielectric constant of the foam, attenuation of the signal through the strips etc. Specifications of the prototype detector panels Foam thickness 5 mm Foam thickness 5 mm Foam density 43 kg/m 3 Foam density 43 kg/m 3 Aluminum foil thickness 0.2 mm Aluminum foil thickness 0.2 mm 50 panels are in production

21B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March Mylar sheets Used for glass electrode and pickup panel isolation Using till now, mylar sheets barrowed from Fermilab Found out that Garfilm EMCL produced by M/s Garware Polyester Ltd suits our requirement well Thickness 100µm Thickness 100µm Breakdown voltage 13.5KV Breakdown voltage 13.5KV

22B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March Issues on fast preamplifiers Avalanche charges are a factor of 100 smaller compared to streamers Typical charges 1pC; (~1mV across 50Ω load) Hence the need for external amplification; typically BARC, ED designed HMC packages are being fabricated at BEL

23B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March Electronics and DAQ for prototype Design of all components of the data acquisition system was completed Production and assembly of nearly all the circuit boards and modules is completed Major sub-systems were integrated along with the on-line data acquisition software successfully Hybrid version of the preamplifiers being fabricated by Bharat Electronics Limited (BEL), Bengalooru

24B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March Software tools and utilities On-line web portal for monitoring chambers under test as well as ambient conditions of the laboratories Web based electronic log book Web based electronic inventory utility Agenda server All these tools can be scaled up and deployed for prototype detector and even for ICAL

25B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, University of Delhi, March Summary and plans Production of 1 m 2 chambers using Italian glass Production of 1 m 2 chambers using Japanese glass for prototype detector Work on bakelite versions to continue (at SINP, VECC, BARC etc) Long term tests and characterisation of large area chambers to continue Finalisation of various materials, processes and vendors, RPC mechanics etc Final integration of electronics and DAQ for prototype detector New labs getting equipped; can take up dedicated and detailed studies