Tungsten-iodine quartz lamp with on-off control is mounted at focus of ellipsoidal reflector and shutter is mounted at conjugate focus. Flux sensor monitors lamp and actuates shutter which emits a heat pulse when the radiant flux builds up to requisite level

Russell, L. D.

English

NASA Technical Reports Server

December 1970
	 Brief 70-10694 
High Intensity Heat-Pulse Source Operates Without Cooling System 
Shutter 
Rotary 
Solenoid 
Shutter	 I 
Solenoid	 I 
and Flux	 I	 Line 
Sensor	 L______ 
Control	 I Power 
Flux Sensor' 
" Radiant Flux  
1	 Lamp	 1 
Conjugate Focus	 Power	 I 
Control 
Ellipsoidal	 Reflector 
Shutter Blade
The problem: 
High intensity radiant energy pulses are ordinarily 
obtained from a continuously operating source, via 
a shuttering mechanism. However, provisions must be 
made for dissipating the excessive heat produced 
by the source, and for preventing damage to the 
shutter. Elaborate mechanisms must be employed to 
place an externally cooled shield between the shutter 
and the source when the shutter is not open. It is 
desirable to have an apparatus that will operate 
effectively without a cooling system to produce high 
intensity radiant heat pulses of specified magnitude 
and duration.
The solution: 
A tungsten-iodine quartz lamp which can readily 
be turned on and off is mounted at one focus of 
an ellipsoidal reflector, and a shutter is mounted 
at the conjugate focus. A flux sensor monitors the 
lamp and actuates the shutter which emits a heat pulse 
when the radiant flux builds up to a requisite 
level. The lamp is turned off at the end of the 
shuttered pulse. 
How it's done: 
As shown in the diagram, a high intensity radiant 
heat source (e.g., a 750-watt tungsten-iodine quartz 
lamp) is located at one focus of a polished el-
(cunhtijued o erleat) 
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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lipsoidal reflector, and a thin pivoted-blade shutter 
is located within the region of the conjugate focus. 
The object to be irradiated is placed immediately 
outside the shutter so that it is substantially in the 
conjugate focal region in order to receive maximum 
energy from the source. 
The lamp is turned on, and the intensity of the 
emitted radiation is monitored by a semiconductor 
sensor. When the flux reaches a desired level, the 
sensor and solenoid control circuit actuates the shut-
ter which produces a radiant heat pulse of cali-
brated intensity and duration. At the end of the 
pulse the lamp is turned off. The shutter can be 
adjusted to vary the pulse duration from a few milli-
seconds to several seconds. With a 750-watt lamp, 
the flux level can be varied from about 5 to 25 
watts/cm 2 . Since the lamp is turned off at the end of 
the pulse, it is only slightly longer than necessary 
to irradiate an object. Thus there is no prolonged 
high temperature to damage any of the components, 
thereby obviating the need of water or forced-air 
cooling.
Notes: 
I. The heat source and control circuitry can be 
mounted on a single portable chassis. The unit is 
especially useful for calibrating and testing thermal 
sensors and heat transfer gages (e.g., gages used 
for measuring transient temperatures in shock 
tunnels.) 
2. Requests for further information may be directed 
to:
Technology Utilization Officer 
Ames Research Center 
Mail Stop N-240-2 
Moffett Field, California 94035 
Reference: B70-10694 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to: 
Patent Counsel 
Mail Code 200-11 A 
Ames Research Center 
Moffett Field, California 94035 
Source: L. D. Russell 
Ames-Research Center 
(ARC- b 178)
S 
Brief 70-10694	 Category 01,03


High intensity heat-pulse source operates without cooling system

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