Proportional chambers and multiwire drift chambers at high rates
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.
- Research Organization:
- Brookhaven National Lab., Upton, N.Y. (USA)
- DOE Contract Number:
- EY-76-C-02-0016
- OSTI ID:
- 5209533
- Report Number(s):
- BNL-23560; CONF-770753-13
- Country of Publication:
- United States
- Language:
- English
Similar Records
Charged particle detector system for ISABELLE spectrometers
Second coordinate readout in drift chambers by charge division
Related Subjects
430400* -- Particle Accelerators-- Storage Rings
440104 -- Radiation Instrumentation-- High Energy Physics Instrumentation
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
AMPLIFIERS
DRIFT CHAMBERS
EFFICIENCY
ELECTRONIC EQUIPMENT
ISABELLE STORAGE RINGS
MEASURING INSTRUMENTS
MULTIWIRE PROPORTIONAL CHAMBERS
OPERATION
PREAMPLIFIERS
PROPORTIONAL COUNTERS
RADIATION DETECTORS
RESOLUTION
SPACE CHARGE
STORAGE RINGS
TIME RESOLUTION
TIMING PROPERTIES