3.9 EFFECTIVENESS OF INSTRUMENTATION Not all of the instrumentation installed in the aircraft operated satisfactorily on every flight. However, in no case did an aircraft penetrate the cloud without sufficient instrumentation functioning pro~ perly to provide the necessary data to satisfy the objectives of this project. Film methods were 100 percent successful in measuring the total dose received by the aircrew on the mission. The photopanel func- tioned on every penetration, with good pictures resulting from each instrumnt. On one penetration the pilot set the camera speed on the "slow" position, resulting in one picture every 20 seconds while in the Cloud,instead of the desired rate of three pictures per second, The automatic recording instruments were designed to masure radia- tion rates up to 2,000 r/hr. On penetrations where the dose rates were quite low, continuous data were not obtained on the return flight. In these cases the total mission dose was always less than 2 r. The PMeter failed to fimction on only two of the flights. Thus satisfactory operation of this instrument was obtained in more than 90 percent of the flights, On the two occasions where the PrMeter failed to function, the fault was in the method of installation and not in the instrument itself, Some trouble was experienced with the Bioscel and Sigmatron, Both of these instruments were battery powered. Even with frequent checks of the battery voltages, satisfactory performance was obtained only about 75 percent of the tims. Zero drift was especially troublesome in the Bioscel, leading to poor results at low dose rates, The Signatron was designed to measure up to 25 r on the low range. Total dosages smaller than 1 r were not reliably indicated by this instrumnt, Film measurements were considered to be accurate to t 10 percent. Measurements made with the T1B were considered accurate to + 10 percent. The PeMeter, Bioscel, and Sigmatron were considered to give an accuracy of t 20 percent. As mentioned in Section 3.3, the P-Meter gave readings about a factor of two higher than film devices, Greater sensitivity and response of the P=-Meter to gamma radiation of low energies appears to be the reason for this discrepancy, On the average, the Bioscel and Sigmatron read 15 percent and 25 percent higher respectively than did the film dosimeters, The flight instruments installed in the photopanel functioned properly on each flight. Indicated altitudes wore considered to be correct = 500 feet. Times of penetration were accurate to the nearest minute. The accelerometer installed in the photopanel was not considered to be reliable in giving indications of turbulence in flight. The maximum and minimum needles vibrated to the limit of their movement on takeoff, Photographic records were available of the mter fluctuations within the cloud but could not be correlated with the verbal reports of the pilots concerning conditions of flight within the cloud, 33 BEST AVAILABLE COPY