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Project 8.5-~ Airborne High Resolution Spectral Analysis ~ R. Zirkind
OBJECTIVE
To determine the spectral characteristics of the radiant power
of an airburst fireball prior to its being shocked by the reflected
wave,
INSTRUMENTATION
The spectral distribution of the radiant power is obtained
from a medium quartz Hilger spectrometer.
The spectrum is sampled
in narrow bands by photocells in the visible region and PbS cells
in the infra-red.
The electrical signal is then recorded on an
Ampex 814 tape recorder, with a resolution time of 150 «sec.
The
transmission measurement is accomplishei by beaming a pulsed light
signal of known output and spectral distribution from a fixed point
on the ground towards the aircraft,
The attenuated beam is received
by a detector in the aircraft and recorded on a Heiland recorder,
The detector consists of two filtered photomultiplier tubes sampling
two spectral regions, (1) .3-.55 microns and (2) .6-1.05 microns.
In addition, a quartz filtered calorimeter, 22 degrees field of view,
is utilized to measure the approximate radiant exposure received at
the spectrometer.
RESULTS
The aircraft was located at the desired position, namely 22,000
feet absolute, directly over ground zero at T,, during the entire
length of the thermal pulse,
The spectrometer operated normally and to date good data has been
obtained on 10 channels
~ 3, ~
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