Instrument automatically performs a nondestructive chemical analysis of surfaces and transmits the data in the form of electronic signals. It employs solid-state nuclear particle detectors with a charged nuclear particle source and an electronic pulse-height analyzer

Turkevich, A.

English

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Alpha Partic
To Telemeter 
Transmitter 
October 1965	 Brief 65-10317 
NASA TECH BRIEF H 
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. 
Instrument Performs Nondestructive Chemical Analysis;

Data Can Be Telemetered 
The problem: Devising a lightweight instrument 
for nondestructive chemical analysis of surfaces. The 
instrument must automatically perform the analysis 
and provide the resultant data in the form of elec-
tronic signals which can be transmitted to remote sites. 
Such an instrument was particularly required for 
chemical analysis of lunar and planetary constituents 
and transmission of the data via telemetry to receiving 
stations on the earth. 
The solution: An instrument employing simplified 
solid-state nuclear particle detectors in conjunction 
with a source of charged nuclear particles and an elec-
tronic pulse-height analyzer. The scattering of the 
charged particles from the atomic nuclei in the sample 
result in characteristic spectra.
How it's done: For relatively low-energy particles, 
such as alpha particles from the usual radioactive 
sources, and for those elements that are heavier than 
aluminum, the large-angle scattering of heavy charged 
particles is primarily Rutherford scattering For light 
elements such as carbon and oxygen, and particularly 
with rather high-energy alpha particles such as those 
from Cm244, nuclear effects enhance the scattering 
above that predicted from pure Rutherford scattering. 
For other light elements, such as nitrogen and fluo-
rine, protons from (alpha, proton) reactions can also 
be expected. 
The analysis of solids (the top 1 to 100 microns) is 
best conducted in a vacuum. A monochromatic, colli-
mated beam of charged particles (e.g., alpha particles 
from a thin radioactive source) bombards the surface 
(continued overleaf) 
AM 
qW
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
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of the sample. Some of the charged particles scattered 
from the atoms (Rutherford scattering) within the 
sample strike the surface of a small solid-state (sur-
face-depletion-type) detector placed at a high scatter-
ing angle (1600 average) approximately 3 centimeters 
above the surface of the sample. The amplified pulses 
from the detector are converted into a particle count-
energy spectrum. This spectrum may be encoded and 
telemetered to give analytical information on the kinds 
and amounts of elements present in the test sample. 
Notes: 
I. Previous experimental detector systems described 
in the literature have employed cumbersome and 
complex magnetic spectrometers. The novelty of 
this instrument lies in the use of a simplified solid-
state detector system. As designed for use in the 
analysis of planetary constituents, the entire instru-
ment weighs approximately eight pounds. 
2. With some modification the instrument can be 
adapted for nondestructive chemical analysis of 
surface films, gases, and solid samples in labora-
tories or in chemical process industries.
Further information concerning this innovation is 
described in "Chemical Analysis of Surfaces by 
Use of Large-Angle Scattering of Heavy Charged 
Particles", by Anthony Turkevich, Science, 134, 
672, 8 September 1961. Inquiries may also be di-
rected to: 
Technology Utilization Officer 
Jet Propulsion Laboratory 
4800 Oak Grove Drive 
Pasadena, California, 91103 
Reference: B65-10317 
Patent status: NASA encourages commercial use 
of this innovation. No patent action is contemplated 
by NASA.
Source: Enrico Fermi Institute 
for Nuclear Studies, University of 
Chicago, under contract to
Jet Propulsion Laboratory 
(JPL-SC-078) 
Brief 65-10317	 Categories 01, 02, 03


Instrument performs nondestructive chemical analysis, data can be telemetered

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