Silicon Detector and Micromodule Production: Present Status

Production of 1000 detectors completed Wafers under process for fabricating 100 spare detectors Production of 900 modules completed Production to complete 1000 micromodules and 100 spares is being carried out at BEL The work order placed on BEL has been amended so that modules can be dispatched directly from BEL

Micromodule Production The production has been launched at BEL in September, 2006 in the presence of Dr Anna Peisert, CERN First lot of 120 Nos of micromodules was sent to CERN from BARC in December, 2006 Two lots of 300 and 450 modules have been dispatched to CERN in March, 2007 from BEL and have been received by CERN Total 870 ( ) modules have been dispatched so far The production of 1100 modules is expected to be over by the end of April.

Micromodule Production: Assembly & Quality Control 1.Visual inspection of the detector 2.Total current measurement and biasing for 5 min at 300V for checking stability of current. 3.Gluing of detector to ceramic and curing for 5 hours under IR lamps at ~ 38 0 C 4.Visual inspection of ceramic tiles for checking physical damage to detector 5.Total current measurement and biasing for 5 min at 300V for checking stability of current.

6.Gluing of ceramic to Al tiles 7.Visual inspection of Al tiles for checking physical damage to detector 8.Total current measurement and biasing for 5 min at 300V for checking stability of current. Unstable detectors, Ceramics and Tiles are kept at 300V for long time to check if they stabilize and are accepted only if they are stable The ceramics and Al tiles are identified by the barcodes and data of each measurement ( production date, detector barcode, corresponding ceramic & Al tile bar code, IV data generated at various levels) is being put in the CRISTAL data base.

Summary of work done at CERN Dr Anita Topkar & Shri Praveenkumar S visited CERN during January 15-February 3, 2007 (Twenty days) Reception tests were carried out for the first lot of 120 modules which was sent to CERN during December, 2006 The performance of modules was verified by carrying out measurements on these modules. Only one module was rejected because of high current, but no physical damage was observed on this detector.

After reception tests, the modules were checked for bond test at the CERN Bonding Lab. Ten bonds were put on two pads of each detector and bond pull test has been carried out for all detector ( strength of bond, the location where the bond breaks during bond pull tests, uniformity of bond pull force required to break the bond). The quality of surface of the detector ( cleanliness, adhesion of the Al film, uniformity of bonding parameters) has been found to be very good – next to Hamamatsu, better than Taiwan & Russia The optimized bonding parameters will be subsequently used for bonding the Indian detectors with the hybrid

Ladders ( 8 modules per ladder) were assembled for temperature cycling of the detectors Temperature cycling from – 30 0 C to C was carried out on detectors and the detectors were found to be stable after temperature cycling The data of all measurements carried out at BEL till February on ceramics and tiles has been updated in the CRISTAL data base Hard copies summarizing tests on detectors carried out at various levels ( detector, ceramic, tiles, after temp cycling, bonding tests, etc) for 120 modules have been generated. Such hard copies will be kept by CERN for all modules in order to quickly track the performance/tests/progress at various levels.