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Title: Performance of 0. 75 mm pitch MWPC'S operating at high rate

Conference ·
OSTI ID:6468978

Three Multiwire Proportional Chambers (MWPC) with high rate capability have been constructed for Fermi National Accelerator Laboratory experiment 705 (Charmonium and Direct Photon production by ..pi../sup +-/, p and /bar p/ at 300 GeV/c). Each chamber, with a sensitive area of 308 cm/sup 2/, consists of three anode planes, wound with 12.5 ..mu..m diameter gold-plated tungsten/rhenium wire, facing 25 ..mu..m graphite-coated kapton cathode planes at a distance of 3 mm. Wire spacing in two of the MWPC (PC-B1 and PC-B2) is 0.75 mm and 1.00 mm in the third one (PC-B3). After a few weeks of running on ''Magic Gas'' with a beam flux of up to /approximately/10/sup 7/ particles/cm/sup 2/sec, severe damage occurred to the graphite coating. All cathode planes were replaced by aluminized kapton, and the chambers worked successfully for the next 3 months until the end of the run, when a 10% efficiency drop was observed after a total accumulated charge of /approximately/1 C/cm of sense wire. After the end of the run the chambers were disassembled and inspected. A white deposit with a characteristic ''wire pattern'' etched away from the Al coating was observed in the region of the beam spot. 10 refs., 8 figs., 1 tab.

Research Organization:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
DOE Contract Number:
AC02-76CH03000
OSTI ID:
6468978
Report Number(s):
FNAL/C-89/21-E; CONF-881103-47; ON: DE89007483; TRN: 89-008583
Resource Relation:
Conference: IEEE nuclear science symposium, Orlando, FL, USA, 9 Nov 1988; Other Information: Portions of this document are illegible in microfiche products
Country of Publication:
United States
Language:
English