_ 444 7 SY (eRIF) Project 8.5 - Airborne High Resolution Spectral Analysis - R, 2irkind OBJECTIVE To determine the spectral characteristics of the radiant pover of an sirburst fireball prior to its being shooked by the reflected wave, INSTRUMENTATION The spectral distribution of the radiant power is obtainei foom 2 sedicm Guarts Nilge: spectrometer, Be spectrum is sespled 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 tine of 150 ~« sec. The transmission measurement is accomplishei by beaming a pulsed light signal of known output ani spectral distribution from ea fixed point on the grouni towards the aircraft. The attenuated beam is received by a datector in the afireraft and recormie! on a Helland recorier. The detector consista of two filtere! photomultiplier tubes sampling two spectral regions, (1) .3-.55 microns and (2) .6-1,05 mtcrons. In addition, a quarts filtered calorimeter, 22 degrees fieli of viev, de utilisel to measure the approximate raiiant exposure receivei at the spectrometer. iromzs BEST AVA ILABLE COPY The aircraft was loanted at the desired posi<ion, namely 22,000 feet absolute, directly over ground sero at T,, during the entire length of the thermal pulse. The spectrometer operated normally and to date good data has been ta “fy ~ oan ¥ rey obtained on 1° channels . 7 34 &