Radioactive-nuclide system automatically monitors animals in the field, using radioactive tracers affixed to the animals, Geiger-Muller tube radiation detectors, and event-recorders. Four animals can be monitored simultaneously within a 32-m circle, with each animal as far as 1 m from its associated detector

Eisler, W. J., Jr.

Frigerio, N. A.

English

NASA Technical Reports Server

August 1969	 CORRECTED COPY	 Brief 69-10286 
AEC-NASA TECH BRIEF 
YES --
AEC-NASA Tech Briefs announce new technology derived from the research and development program of the U.S. AEC or 
from AEC-NASA interagency efforts.They are issued to encourage commercial application. Tech Briefs are available on a 
subscription basis from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Requests for individual copies or questions relating to the Tech Brief program may be directed to the Technology Utilization 
Division, NASA, Code UT, Washington, D.C. 20546. 
Mobility Monitoring System for Ecological Studies 
The problem: 
To develop a device for long-term monitoring of 
the locations of animals for ecological studies. Gen-
erally, telemetering systems are used. 
The solution: 
A radioactive-nuclide system automatically moni-
tors animals in the field, using radioactive tracers 
affixed to the animals, Geiger-Muller (GM) tube radi-
ation detectors, and event-recorders (1). Four ani-
mals can be monitored simultaneously within a 32-m 
circle, with each animal as far as I m from its asso-
ciated detector. A permanent recod covers 1 week 
on an event-recorder chart. 
When residence time at a particular location is to 
be monitored, the radioactive-nuclide method has 
certain distinct advantages over telemetering systems. 
Since the "transmitter" is nuclear rather than elec-
tronic, it is inexpensive, very small, and free of 
maintenance and battery-life problems; since there 
are no tuned circuits or antennas, the detection equip-
ment can be simple, cheap, and easily adapted to com-
pletely automatic operation in the field. 
How it's done: 
Several requirements were established for the sys-
tem: The nuclide must be capable of fixation in a form 
easy to attach to the animal without danger of loss 
into or contamination of the environment. The radia-
tion dose to the animal must be minimal, but system 
sensitivity should be high enough for positive detection 
at 1 m or more. The system must be capable of un-
attended operation in any weather, with checks re-
quired only weekly. Finally the system must provide 
positive indication regardless of the orientation or 
self-shielding of animals weighing 1 kg or more.
Selenium-75 was chosen as the nuclide; it is avail-
able at a high specific activity and low cost in a form 
easy to incorporate into epoxy resins. These resins 
adhere firmly to nearly any surface to form hard, non-
toxic coatings that resist mechanical damage or leach-
ing of the radionuclide. Since 755e decays by electron-
capture, charged particles are not emitted and a high 
local skin dose is avoided. 
The chief radiations (77- to 405-key gamma rays) 
readily penetrate tissue with a half-value of about 
7 cm and give high counting efficiency with a mini-
mum gamma dose to the animal. The half-life of 75Se 
(120 days) is long enough to minimize the overall dose 
to the animal and to limit the possibility of liberation 
of a long-lived radiation hazard into the environment. 
Miniature GM tubes were selected for effective 
detection; they are inexpensive, rugged, and small 
enough for unobtrusive placement, with excellent 
sensitivity to 75 Se radiation. Their operating voltage 
(375 to 400 v) is low enough for an inexpensive 
battery supply; their pulse output is large enough to 
drive 15 m or more of coaxial cable; and their sensi-
tivity is well adapted to the rugged and inexpensive 
multichannel, single-event recorders. 
Encapsulation of the GM tube in resin, within a 
five-sided Pb shield, makes a rugged, sensitive, and 
weatherproof detector that is easily attached to 
weatherproof cable. The background count rate for 
these detectors is less than 1 min d . At 1 m, 50 pc of 
75Se, contained in a 1-kg tissue phantom, gives a count 
rate of 10 mind . The response follows the inverse-
square law, so the same sample gives 110 mind
 at 30 
cm and 1,000 min' at 10 cm. This capsule is placed 
on a bird band.
(continued overleaf) 
This document was prepared under the sponsorship of the Atomic	 liability resulting from the use of the information contained in this 
Energy Commission and/or the National Aeronautics and Space document, or warrants that the use of any information, apparatus, 
Administration. Neither the United States Government nor any per-	 method, or process disclosed in this document may not infringe pri-
son acting on behalf of the United States Government assumes any vately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19690000285 2020-03-16T17:47:01+00:00Z
A weatherproof enclosure, made of marine plywood, 
houses the electronic circuitry, recorder, and battery 
supply. 
Reference: 
N. A. Frigerio and W. J. Eisler, Jr., Ecology 49(4) 
(1968). 
Notes: 
1. This information may interest persons and organi-
zations concerned with animal behavior. 
2. Inquiries may be directed to: 
Office of Industrial Cooperation 
Argonne National Laboratory 
9700 South Cass Avenue 
Argonne, Illinois 60439 
Reference: B69-10286 
Source: N. A. Frigerio and W. J. Eisler, Jr. 
Biological and Medical Research Division
(ARG- 10342)
Patent status: 
Inquiries concerning rights for commercial use of 
this innovation may be made to: 
Mr. George H. Lee, Chief 
Chicago Patent Group 
U.S. Atomic Energy Commission 
Chicago Operations Office 
9800 South Cass Avenue 
Argonne, Illinois 60439 
Brief 69-10286	 Category 04


Mobility Monitoring System For Ecological Studies

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server