Three curved plate energy analyzers coupled with three electron multiplier tubes detect and measure low energy electron flux in several directions simultaneously

Lind, D. L.

Ogilvie, K. W.

Wilkerson, T. D.

English

NASA Technical Reports Server

July 1965	 Brief 65-10213 
NASA TECH BRIEF 
NASA Tech Briefs are issued by the Technology Utilization Division to summarize specific 
technical innovations derived from the space program. Copies are available to the public from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia, 22151. 
Multiaxial Analyzer Detects Low-Energy Electrons 
VA
SYSTEM DIAGRAM 
The problem: To provide a method for detecting 
and measuring the intensity and direction of flow of 
electrons between zero and 10 key . Although useful 
studies of electrons can be made with a wide angle 
device such as a Faraday cup, measurements made 
simultaneously in several directions can offer distinct 
advantages. 
The solution: A system of three curved plate energy 
analyzers coupled with three electron multiplier tubes 
that is stepped uniformly through the energy interval 
by a common analyzer supply voltage.
How it's done: The three energy analyzers and 
electron multiplier tubes are arranged to measure elec-
tron flux in several directions simultaneously. Each 
detection system is completely independent except for 
the common stepping supply for the energy analyzers. 
As voltage applied to the energy analyzers is in-
creased in steps, higher energy electrons will be able 
to complete the circular path to the multiplier tubes. 
Current output from the multiplier tubes passes to the 
comparator circuit where it is compared with a stand-
ard current. Because the output current from the mul-
tiplier tubes increases with the number of elerons 
(continued overleaf) 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States Govern-
ment, nor NASA, nor any person acting on behalf of NASA: A. Makes 
any warranty or representation, express or implied, with respect to the 
accuracy, completeness, or usefulness of the information contained in
this document, or that the use of any information, apparatus, method, 
or process disclosed in this document may not infringe privately-owned 
rights; or B. Assumes any liabilities with respect to the use of, or for 
damages resulting from the use of, any information, apparatus, method, 
or process disclosed in this document.
https://ntrs.nasa.gov/search.jsp?R=19650000211 2020-03-11T17:23:51+00:00Z
entering and because the gain of the tubes decreases 
with applied potential, electron flux at each energy 
level is determined by the change in applied potential 
required to maintain constant output current. The 
multiplier tubes are, therefore, operated as null de-
tectors and a fraction of the potential applied to them 
is transmitted as a measure of electron flux. This pro-
vides a dynamic range of five orders of magnitude, 
and an approximate logarithmic compression of the 
scale of flux. This instrument will operate in any vac-
uum system with a pressure below 10- 5 mm of 
mercury.
to ionospheric physics, explosion physics, nuclear 
devices, and auroral studies. 
2. Inquiries concerning this invention may be directed 
to:	
Technology Utilization Officer 
Goddard Space Flight Center 
Greenbelt, Maryland, 20771 
Reference: B65-10213 
Patent status: NASA encourages the immediate 
commercial use of this invention. Inquiries about ob-
taining rights for its commercial use may be made to 
NASA, Code AGP, Washington, D.C., 20546. 
Source: Keith W. Ogilvie, 
Notes:	 Don L. Lind, and 
1. This invention should be of interest to organiza- 	 Thomas D. Wilkerson 
tions dealing with low-energy electron flux related	 (GSFC-329) 
Brief 65-10213
	
Category No. 01


Multiaxial analyzer detects low-energy electrons

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