Silicon carbide, insensitive to visible light, is used in photodetectors. System contamination can be monitored during the normal operation without interference to the operator, and without shielding from ambient light

Glenn, C. G.

Kennedy, B. W.

English

NASA Technical Reports Server

December 1968
	
Brief 68-10413 
NASA TECH BRIEF 
NASA Teèh Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
UV Detector Monitors Organic Contamination of Optical Surfaces 
Cetain outgassed products of organic materials tend 
to degrade the optical properties of lenses and lens 
systems, mirrors, or windows, particularly in closed 
systems. Such contamination is often difficult to moni-
tor, since conventional photodetectors must be shielded 
from ambient light. However, silicon carbide (SiC) 
ultraviolet detectors have a peak spectral response at 
2800 to 3800 angstroms and thus are insensitive to vis-
ible light and are nearly solar blind. Such detectors 
can produce a photovoltage of 1 millivolt to 1.6 volts, 
depending on the incident flux density. The obvious 
advantage of such detectors is that system contamina-
tion can be monitored during normal operation with-
out interference to the operator and without the prob-
lems of excluding ambient light from the detector. 
SiC detectors could be employed to determine the 
effects of contamination on UV transmittance and re-
flectance measurements in laboratory thermo-vacuum 
systems. Also, the detectors could be attached di-
rectly to the lenses of various optical systems to contin-
uously monitor changes due to contamination buildup. 
Typical uses are in various research laboratories, 
television and photographic studios, and astronomical 
observatories. 
Note: 
No additional documentation is available. Ques-
tions may be directed to: 
Technology Utilization Officer 
Marshall Space Flight Center 
Huntsville, Alabama 35812 
Reference: B68-10413 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to NASA, Code 
GP, Washington, D.C. 20546. 
Source: B. W. Kennedy and C. G. Glenn 
(M FS-20246) 
Category 01 
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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UV detector monitors organic contamination of optical surfaces

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