Multiplier is formed of glass and includes cylindrically-shaped main channel element having length-to-diameter ratio of 50 to 1. Element has open slot along its length. Attached to slot edges are two glass plates set at an angle to each other. Inside surfaces are coated with secondary electron emissive coating

Schmidt, K. C.

English

NASA Technical Reports Server

January 1975	 B74-10275 
NASA TECH BRIEF 
NASA Pasadena Office
	
- L 
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. 
Improved Channel Multiplier for Radiation-and-Particle Detectors 
An improved channel multiplier has been develop-
ed for radiation-and-particle detectors. The multiplier 
amplifier detects X-rays, ultraviolet rays, and charged 
particles. 
The multiplier as shown in Figure 1 is formed of 
glass. It includes a cylindrically-shaped main channel 
element having a length-to-diameter ratio of 50 to 1. 
The element has an open slot along its length. 
Attached to the slot edges are two glass plates set at an 
angle to each other. The plates are 12 cm long and 
have a maximum separation of 1 cm. This provides a 
12-cm' detection area. The inside surfaces of the 
plates and of the main element are coated with a 
secondary electron emissive coating. 
The main element also includes an aperture open-
ing into a curved multiplier element. The curved 
element ends in a collector cap which collects 
multiplied secondary electrons. The curvature reduces 
any feedback of positive ions moving opposite to an 
electron stream.
Aperture 
Curved	
Main 
Element
 Element
Slot 
Vout	 V, 
- - --	
--	 Plates 
Figure 1 Multiplier Configuration
V3 
V1
Curved 
Element 
Figure 2. Multiplier Without Aperture 
When radiation or charged particles strike the 
multiplier emissive coating, secondary electrons are 
generated. The electrons are guided between different 
voltage potentials to the collector cap. In this case, 
electrons are accelerated to the slot by the potential 
between voltages V 2 and V 1 , V 2 more positive than V1. 
The electrons passing through the slot strike its inside 
surface, generating an additional emission. The 
resulting emission is then accelerated between 
voltages V 4 and V 3, V 4 being positive with respect to 
V3.
Once the electrons enter the curved element 
through the aperture, they are again accelerated 
between voltages V 6 and V 5; V 6 is positive compared 
to V 5 . Electrons striking the collector cap are then 
input to recording equipment. 
A slightly modified design (see Figure 2) includes a 
funnel-shaped structure. The structure also includes a 
similar curved element. The voltage distribution is 
similar to that in Figure 1.
Funnel-
Shaped 
Structure 
(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=19740000275 2020-03-17T13:57:24+00:00Z
A 
Note:	 Patent Status: 
Requests for further information may be directed 	 This invention has been patented by NASA (U.S. 
to:	 Patent No. 3,758,781). Inquiries concerning nonex-
Technology Utilization Officer 	 clusive or exclusive license for its commercial develop-
NASA Pasadena Office	 ment should be addressed to: 
4800 Oak Grove Drive 	 Patent Counsel 
Pasadena, California 91103	 NASA Pasadena Office 
Reference: TSP74-10275 	 4800 Oak Grove Drive 
Pasadena, California 91103 
Source: Kenneth C. Schmidt of

Bendix Corp.
under contract to

NASA Pasadena Office

(NPO-12128) 
Categories: 03 (Physical Sciences) 
B74-10275	 02 (Electronics Systems)


Improved channel multiplier for radiation-and-particle detectors

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