Proportional chambers and multiwire drift chambers at high rates [electronic resource].
- Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 1977.
- Physical Description:
- Pages: 13 : digital, PDF file
- Additional Creators:
- United States. Department of Energy. Office of Scientific and Technical Information
- The high event and particle rates expected for ISABELLE intersecting storage rings raise the question whether PWC's and drift chambers, now widely in use in experiments, still can operate under such conditions. Various effects depend on the number of avalanches produced per length of wire N and the size of the avalanche Q, i.e., on the number of positive ions created in an avalanche. Therefore the important parameter for the following discussion is the product QN. The minimum Q is determined by the type and noise level of preamplifiers used. Examples are given for a typical low noise amplifier as well as for a typical integrated ''cheap'' amplifier. The rate/wire length N depends on the chamber arrangement, wire spacing, etc. In multiwire drift chambers, a single wire shows space-charge effects reducing the pulse height by 1% at a rate of N = 7 x 10/sup 3/ mm/sup -1/ sec/sup -1/. At a rate of N approximately equal to 10/sup 5/ mm/sup -1/ sec/sup -1/ an efficiency loss of the order of 1% was noticed. The aging effect due to deposits on the anode wire can be reduced using low noise amplifiers and low gas gain to such an extent that a lifetime of about half a year at ISABELLE can be expected. The use of conventional cheap preamplifiers will result in a typical lifetime of about 30 days. Improvements are probable. The time resolution of ..delta..t/sub r/ = 4 nsec fwhm seems adequate for event rates of 10/sup 7/ sec/sup -1/. The memory time ..delta..t/sub m/ greater than or equal to 100 nsec may cause serious problems for pattern recognition depending on layout and readout. The use of induced signals on cathode pads, thus reading out shorter parts of the wire, can solve the problem.
- Published through SciTech Connect.
Isabelle workshop, Upton, NY, USA, 18 Jul 1977.
Brookhaven National Lab., Upton, N.Y. (USA)
- Funding Information:
View MARC record | catkey: 14402949