ble variations in the original recording speed, which, if found, were compensated by subpro- graming the 704 computer. The high-range channel on the GITR tape was fed into the computer where the time between each radiation pulse was measured against a 1-Mc timing signal in the computer. Each radiation pulse interrupted the timing Signal long enough to store the cumu- lated time during the previous interval in the computer memory bank. Since only 48 msec (a time much shorter than the duration of a radiation pulse from the GITR) were required by the 704 to store the cumulated time, the timing signal for the next interval could be Started by the Same radiation pulse; thus, complete time-between-pulse information was obtained. Usually all information on the high-range channel of a GITR could be stored in the 704 memory bank. The computer was ther programed to compute the average dose rate over each interval between radiation pulses, to cumulate the dose increments and to sum the time intervals. The GITOUT procedure is more accurate than the 704 procedure, since it uses the timing channel information on-the tape; however, the difference in accuracy between the 704 and the GITOUT cannot be more than 1 percent. GITR records from the EC-2 and the platform station aboard the DD-592 and all remaining low-range channe! information from the destroyers were read out, using the GITOUT and the fixed-interval-counting method described in Section 3.1.1. All 60-hour tapes had to be electronically stretched, a process that is also described in Section 3.1.1. The records for 0 to 15 minutes and 0 to 6 hours are presented in this section (Figures 3.183 through 3.206); the records for 0 to 2.5 minutes are included in Section 3.2. Since no timing blank (Section 2.2.7) was in- cluded in the shipboard control system, zero time was established by measuring 5 minutes on the GITR timing channel starting from the minus-5-minute EG&G signal. Prior to evacuation of the ships for Umbrella, some GITR’s were started manually. Zero time on these records was established by matching first dose rate peaks with GITR’s that received the minus-5- minute signal, aboard the same vessel. Zero time on the EC-2 records for Umbrella was de- termined by caleulating the time of the first peak on the basis of nearby coracle records. Unmodified dose rates are presented, since any radioactive material deposited on the decks was probably removed either by the water accompanying the deposition or by the washdown system. The measurements represent gamma doSe rates resulting from airborne radioactive material at specific positions aboard stationary ships under washdown. Unfortunately, nine of the GITR’s saturated at peak dose rate for about 15 seconds during Umbrella; thus, exact cumulative doses cannot be computed. The peak dose rates for the destroyers have been reconstructed by Project 2.1, using the unsaturated records obtained from GITR’s installed inside the ships. These reconstructed peaks are shown as a dashed line on the appropriate records. The total cumulative dose has been determined by numerical integration, using a straight line between the two dose rate points bounding the period of saturation. The difference between this integ- rated dose and the corrected film pack dose approximates the dose received during saturation. In all cases, more than half the total dose was received during the brief interval of saturation. These values together with the cumulative dose at various times after zero time for the nonSaturated shipboard records are presented in Table 3.27. The total doses registered by film packs positioned within 3 feet of the GITR detector are also given for comparison. For greater ease of comparison with the coracie data, the time and dose rate of the major peaks shown by the shipboard records are summarized in Table 3.28. The normalized doses have also been computed for various times after zero time as described in Section 3.3.2 and are presented in Table 3.29. Because corrections for waterborne radioactivity cannot be accurately made, the cumulative normalized dose is stopped as soon as the gamma record indicates completion of surge transit; therefore, comparison must be made with the observed cose cumulated over the same time interval. Although the cumulative normalized dose contains a number of inherent inaccuracies, it may be used to estimate the relative total amounts of radioactive base surge transiting a given ship. During both Wahoo and Umbrella, the GITR record obtained at the bow station aboard the DD-593 is about double the other records obtained aboard that ship. The differencebetween the corrected film pack dose and the total cumulative dose computed from the GITR record 1s 278 Pages 279 through 281 were deleted.