Anode wire itself is enclosed by three segments. Two on ends are rejector segments, and middle one is primary charge-detecting segment. Anode wire is made from tungsten and is surrounded by enamel insulation. Enamel is covered by segments of vapor-deposited gold. At one point in center segment, gold layer makes direct contact with anode wire

Kraushaar, W. L.

English

NASA Technical Reports Server

NASA TECH BRIEF 
Goddard Space Flight Center H
Rejection 
Segment
Primary 
Segment
Rejection
	 Anode I Segment 
	 I Wire 
December 1974	 B74-10229 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Coaxial Anode Improves Sensitivity of Gas Radiation Counters 
The problem: 
The sensitivity of gas radiation counters is often 
reduced by background (cosmic and gamma) radiation. 
For example, in proportional counters used for the 
measurement of X-rays, gas is ionized by the primary 
low energy X-rays as well as cosmic and gamma rays. 
As a result, low X-ray radiation levels cannot be detected 
in the background of cosmic and gamma radiation. 
Much of the background can be eliminated by special 
protective counters which surround the X-ray counter 
on three sides. But near the ends of the X-ray counter 
anode, where electrical connections are made, no pro-
tective counters have been possible.
The solution: 
A new coaxial anode developed for gas radiation 
counters suppresses background radiation. 
How it's done: 
In the simplified illustration shown, the anode wire 
itself is enclosed by three segments. The two on the ends 
are the rejector (background) segments, and the middle 
one is the primary charge-detecting segment. The anode 
wire is made from tungsten approximately 0.001 inch 
(0.025 mm) in diameter. The wire is surrounded by an 
enamel insulation which is 0.0005 inch (0.013 mm) 
thick. The enamel is covered by segments of vapor. 
deposited gold. At one point in the center segment, the 
gold layer makes a direct contact with the anode wire. 
Gold 
Direct Contact
Enamel 
) Output 
Coaxial Anode
I
(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 Slates	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United Slates 	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19740000229 2020-03-17T13:54:49+00:00Z
The rejection segments are connected in parallel to a 
charge-sensitive amplifier A 1 , while the primary segment 
is connected to amplifier A 2 . The amplifier outputs 
are connected to a detecting circuit (not shown). The 
connection is madeso that the primary segment is in 
anticoincidence with the rejection segments. The ioniza-
tion that is recorded simultaneously on all three seg-
ments is rejected as background interference.
Patent status: 
This invention has been patented by NASA (U.S. 
Patent No. 3,812,358). Inquiries concerning nonexclu-
sive or exclusive license for its commercial develop-
ment should be addressed to: 
Patent Counsel 
Goddard Space Flight Center 
Code 204 
Greenbelt, Maryland 20771 
Note: 
Requests for further information may be directed to: 	 Source: William L. Kraushaar of 
Technology Utilization Officer	 University of Wisconsin 
Goddard Space Flight Center	 under contract to 
Code 207.1	 Goddard Space Flight Center 
Greenbelt, Maryland 20771 	 (GSC-1 1492)
Reference: TSP74-10229 
B74-10229	 Category 03, 02


Coaxial anode improves sensitivity of gas radiation counters

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