Beam impinges on palladium-silver tube, which is target, and heats impinged surface causing local hot spot. Contained gas diffuses through hot spot to meet incoming beam and produce desired particles. When beam is turned off, target spot cools and stops dispensing contained gas

Miller, C. G.

English

NASA Technical Reports Server

August 1974	 B74-10108 
NASA TECH BRIEF 
NASA Pasadena Office	
A 
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 Dispensing Targets for Ion Beam Particle Generators 
.
High-energy particle generators are presently used in 
neutron radiography, reactor pulsing, nuclear safeguard 
studies, and other related fields. They are also used in 
the search for new sources of oil and as aids in locating 
desired ores in mining operations. 
The basic structure of a common particle generator 
comprises an ion beam source, and a particle dispensing 
target which incorporates either deuterium or tritium 
sealed in a container. Deuterium is used for generating 
protons, and tritium, for generating neutrons. When the 
ion beam impinges on the target, the reaction generates 
the desired particles. 
In a newly-designed dispensing target the container is 
a sealed palladium enclosure holding the deuterium or 
tritium gas at atmosheric or higher pressures (see 
figure). The enclosure is a drawn thimble made of 
palladium-silver alloy that is welded or brazed to a 
copper tube. The container inside diameter is approxi-
mately 1/8 inch (3 mm) and the length 1 inch (3 cm).
In use, the ion beam impinges on the palladium-silver 
tube, which is the target, and heats the impinged surface 
causing a local hot spot. The contained gas diffuses 
through the hot spot to meet the incoming beam and 
produce the desired particles. When the ion beam is 
turned off, the target spot cools and stops dispensing 
the contained gas. 
All the surface of the tube other than the tip is 
coated with either copper, silver, or molybdenum. 
These metals are impervious to diffusion of the contained 
gas even when hot. As a result, they confine the effusion 
only to the active spot, as shown in the figure. 
The uncoated exit point of up to 1 mm in diameter 
is formed by masking the tip during the deposition of 
the impervious metal. A further coating of titanium or 
zirconium, or of a suitable rare earth metal such as 
erbium, on the protective coating is used to absorb 
unreacted deuterium or tritium. This maintains the 
vacuum at the desired level of less than 10-4 torr 
during operations. 
-cI.lI-	
I!rl 
Ionized,	
WW Beam
 
• I	
- &s
	
or Tritium
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 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.
0
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Notes: 
The dispensing targets described may be of interest 
to manufacturers of nuclear reactors and to mining 
and petroleum firms. 
Requests for further information may be directed to: 
Technology Utilization Officer 
4800 Oak Grove Drive 
Pasadena, California 91103 
Reference: TSP74.10 108
Patent status: 
This invention has been patented by NASA (U.S. 
Patent No. 3,646,348). Inquiries concerning nonex-
clusive or exclusive license for its commercial develop-
ment should be addressed to: 
Patent Counsel 
NASA Pasadena Office 
4800 Oak Grove Drive 
Pasadena, California 91103 
Source: Charles G. Miller of

Caltech/JPL
under contract to

NASA Pasadena Office

(NPO-13112) 
U.S. GOVERNMENT PRINTING OFFICE: 1974-636-114 
B74-10108	 Category 03 0


Improved dispensing targets for ion beam particle generators

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