High sensitivity amplifier/discriminator for PWC's
The facility support group at Fermilab is designing and building a general purpose beam chamber for use in several locations at the laboratory. This pwc has 128 wires per plane spaced 1 mm apart. An initial production of 25 signal planes is anticipated. In proportional chambers, the size of the signal depends exponentially on the charge stored per unit of length along the anode wire. As the wire spacing decreases, the capacitance per unit length decreases, thereby requiring increased applied voltage to restore the necessary charge per unit length. In practical terms, this phenomenon is responsible for difficulties in constructing chambers with less than 2 mm wire spacing. 1 mm chambers, therefore, are frequently operated very near to their breakdown point and/or a high gain gas containing organic compounds such as magic gas is used. This argon/iso-butane mixture has three drawbacks: it is explosive when exposed to the air, it leaves a residue on the wires after extended use and is costly. An amplifier with higher sensitivity would reduce the problems associated with operating chambers with small wire spacings and allow them to be run a safe margin below their breakdown voltage even with an inorganic gas mixture such as argon/CO2, this eliminating the need to use magic gas. Described here is a low cost amplifier with a usable threshold of less than 0.5 ..mu..A. Data on the performance of this amplifier/discriminator in operation on a prototype beam chamber are given. This data shows the advantages of the high sensitivity of this design.
- Research Organization:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- DOE Contract Number:
- AC02-76CH03000
- OSTI ID:
- 6306789
- Report Number(s):
- FNAL-TM-1158; ON: DE85004271
- Resource Relation:
- Other Information: Portions are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AMPLIFIERS
PERFORMANCE
MULTIWIRE PROPORTIONAL CHAMBERS
BREAKDOWN
DISCRIMINATORS
EXPERIMENTAL DATA
SIGNALS
DATA
ELECTRONIC CIRCUITS
ELECTRONIC EQUIPMENT
EQUIPMENT
INFORMATION
MEASURING INSTRUMENTS
NUMERICAL DATA
PROPORTIONAL COUNTERS
RADIATION DETECTORS
440104* - Radiation Instrumentation- High Energy Physics Instrumentation