TIME OF FLIGHT CORRECTION FOR DETECTOR THICKNESS IN THE MTR FAST CHOPPER TIME ANALYZER
>In order to increase the probability of detecting the neutrons from the MTR fast chopper, five detector banks have been placed together along the neutron flight path. An automatic time correction is desirable for this arrangemert to correct the nominal time of arrival of neutrons in any of these detector banks to a time corresponding to one point in the flight path. This corrects for the transit time of the neutrons across the five detector banks. Continuously varying corrections are necessary since the correction for a given counter spacing changes as a function of the flight time. This system consists of one fixed and four variable delay channels, each channel corresponding to one of the detector banks. Each variable delay channel produces a linearly changing voltage with time. A light pulse from the fast chopper initiates a voltage sweep in a reference channel, and an ionization pulse from the neutron detector bank in which the neutron is detected initiates the voltage sweep in the corresponding variable delayed channel. When the reference voltage and the delayed voltage are equal a timecorrected pulse is generated corresponding to the time of arrival of the fixed channel. This pulse is then stored in the appropriate time channel of the 1024 channel time analyzer as if all of the detector banks were at the same point in the flight path. The resolution of the five bank ten inch detector was reduced to that of the single bank two inch detector. This is an improvement by a factor Iess than 0.05 X Results are reported for an n-heptane of 3.5 at one electron volt which allows one per cent resolution. (auth)
- Research Organization:
- Phillips Petroleum Co. Atomic Energy Div., Idaho Falls, Idaho
- DOE Contract Number:
- AT(10-1)-205
- NSA Number:
- NSA-13-019127
- OSTI ID:
- 4253440
- Report Number(s):
- IDO-16510
- Country of Publication:
- United States
- Language:
- English
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