Liquid nitrogen-cooled gamma ray detector system is made portable by attaching the detector to a fixture which provides a good thermal conductive path between the detector and the liquid nitrogen in a dewar flask and a low heat leak path between the detector and the external environment

Fessler, T. E.

English

NASA Technical Reports Server

March 1966	 Brief 66-10103 
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U. S. space 
program and to encourage their commercial application. Copies are available to the public from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Mount Makes Liquid Nitrogen-Cooled Gamma Ray Detector Portable 
Vent to
	 LJ 
Atmosphere	 E1	 Stainless Steel Cap 
Low 
Heat-Le 
Bellows
Germanium 
Gamma Ray 
Detector 
Brass Disk
Dry Nitrogen Gas
Brass Rod 
Heat Conductor 
Liquid Nitrogen 
Coolant 
Silver Solder I I Brass Disk 
Glass Dewar Flask 
The problem: 
Devise a portable liquid nitrogen-cooled gamma 
ray detector system. Commercially available cryostats 
that are used to maintain a germanium gamma-ray 
detector at operating temperature require attachment 
to a vacuum pump and frequent monitoring and re-
plenishment of the liquid nitrogen coolant. The re-
quired external apparatus limits the portability of the 
detector system.
The solution: 
Attach the detector to a fixture that provides a 
good thermal conductive path between the detector 
and the liquid nitrogen contained in a Dewar flask, 
and a low heat-leak path between the detector and the 
external environment. 
How it's done: 
The fixture is comprised of two sections, a thermal 
conductive section consisting of a brass rod with a 
(continued overleaf) 
This document was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19660000103 2020-03-11T17:35:11+00:00Z
brass disk at each end, and an insulating section con-
sisting of a thin-metal bellows: The upper disk of the 
brass rod assembly serves as a mount for the ger-
manium gamma-ray detector and the bellows, the 
upper end of which is fastened to the stainless steel 
cap on the Dewar flask. 
The dry nitrogen gas that accumulates above the 
liquid nitrogen surrounding the brass rod serves both 
as a suitable detector environment and as additional 
thermal insulation for the system. Since the gas is at 
atmospheric pressure, no external vacuum pump is 
required. One filling of liquid nitrogen in a two-liter 
Dewar flask will effectively cool the detector for ap-
proximately six days.
Notes: 
I. The gamma ray source outside of the flask must 
be at or abovç the level of the coolant. 
2. Inquiries concerning this innovation may be di-
rected to:
Technology Utilization Officer 
Lewis Research Center 
21000 Brookpark Road 
Cleveland, Ohio, 44135 
Reference: B66-10103 
Patent status: 
No patent action is contemplated by NASA. 
Source: Theodore E. Fessler 
(Lewis-259)
S. 
Brief 66-10103	 Category 01


Mount makes liquid nitrogen-cooled gamma ray detector portable

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server