Six-channel radiometer with three ultraviolet detection channels measures temperatures at 2-millisecond intervals. One infrared channel measures total radiation, and two infrared channels measure radiation in discrete spectral intervals at rate of 40 intervals per second. Analyzer consists of optical and electrical system

Farwell, R. P.

English

NASA Technical Reports Server

January 1973
	 B73-10017 
NASA TECH BRIEF
	
-4r Ames Research Center 
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- 
High-Temperature-Radiation Analyzer 
The problem: 
To make simultaneous temperature and spectral 
measurements on surfaces which have temperatures 
as high as 3900 °K and undergo temperature variations 
in time intervals of the order of milliseconds (for ex-
ample, targets illuminated by short bursts of radiant 
energy). 
The solution: 
A six-channel radiometer with three ultraviolet 
(UV) detection channels to measure temperatures at 
.2-millisecond intervals, one infrared (IR) channel to 
measure total radiation, and two infrared channels to 
- measure radiation in discrete spectral intervals at a 
rate of 40 intervals per second. 
How it's done: 
The radiation analyzer consists of an optical and an 
electrical system. The optical system is comprised of 
an 8-inch Cassegrain mirror arrangement to gather 
radiation emitted by the target and direct it to a 
six-sided pyramid reflector which illuminates each of 
six detectors; it includes the sighting, focusing, mod-
ulating, and filtering sections of the radiometer. The 
electrical system includes detection, -preamplification, 
signal processing, logic circuitry, control, and power 
systems; the signal-processing circuitry provides a 
precise analog of the detected radiation. 
The three UV channels use filters to cover a broad 
region of the spectrum in slightly overlapping ranges, 
and 1P28 photomultipliers operating at constant cur-
rent are used to provide measurements of the target 
temperature; measurements in this region are not 
greatly influenced by target emissivity. One of the JR
channels is made to respond to total radiation in the 
spectral range from 0.37 to 8.0 pm by use of a therm-
istor bolometer as a detector; to analyze the spectral 
intensity distribution of the energy emitted by the 
target, the other two JR channels, called the long-
and short-wave spectral channels, are provided with a 
common set of narrow-band optical filters in a rotating 
wheel. One pulse of energy is received through each 
filter during a complete rotation of the wheel. The 
characteristics of each channel are summarized in the 
table. 
Channel	 Function	 PM	 Remarks 
UV temperature 0.25
	
2660° to 3900° K 
2	 UV temperature 0.30 21700 to 3000°K 
3	 UV temperature 0.40 15000 to 2500°K 
4	 Total radiation 0.35-8.0 Thermistor
5	 Short-A spectral 0.5-1.78	 10 intervals; 
PbS detector 
6	 Long-A spectral 2.0-6.3	 10 intervals; 
thermistor 
The radiation analyzer is used to make measure-
ments on a target which has been exposed to chopped 
pulses of energy from an arc source. A mechanical 
phase shifter in the radiation analyzer makes possible 
synchronization so that detection and measurement 
of the target emission in the UV and JR channels 
noted above occur immediately after the target has 
been exposed to arc radiation. An ultrahigh-temper-
attire calibration standard provides high-emissivity 
(continued overleaf) 
	
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https://ntrs.nasa.gov/search.jsp?R=19730000017 2020-03-17T06:38:07+00:00Z
References: 
1. Barnes Engineering Company; Instruction Manual 
for Model R-8A6 Radiation Analyzer. BEG 2408 
0371. 
2. Barnes Engineering Company; Operating and 
Maintenance Instructions for Model 11-170, Ultra-
high Temperature Radiation Reference Standard. 
BEC 2407 0271. 
Notes: 
1. A secondary calibration source, consisting of a 
tungsten ribbon lamp situated behind a frosted sap-
phire window is used as a separate unit; it serves as 
a target at known temperatures for rapidly checking 
the performance of the radiometer.
2. No additional documentation is available. Specific 
questions, however, may be directed to: 
Technology Utilization Officer 
Ames Research Center 
Moffett Field, California 94035 
Reference: B73-10017 
Patent status: 
NASA has decided not to apply for a patent. 
Source: Richard P. Farwell of 
Barnes Engineering Company 
under contract to 
Ames Research Center 
(ARC-10565)
0 
I 
B73-10017	 Category 03


High-temperature-radiation analyzer

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