sticky-pan data in terms of equivalent full-field dose rate.
cluster.
Six collectors were used per
For studies of weathering effects, it was planned to collect three pans of some
clusters as soon after the shot as possible and to collect the remaining three when recovery
of other pans in the same portion of the array was complete. When clusters were used for
statistical studies alone, all six pans were collected at the same time.
3.2.6 Sticky-Pan Counting. Instrumentation for measuring the amount of gamma activity
collected on sticky pans wasinstalled in a tent near Station 1520 on Yvonne. The primary
equipment consisted of two geometries. Each geometry included four GM tubes and a scaler
to measure count rate. Five shelf positions in the geometry allowed pansto be placed at
different distances from the tubes. Ome of these geometries is shown in Figure 2.14. Asa
secondary measurement method, mainly for counting activity toointense forthe first method,
a geometry mounting a Jordan AGB-500B-SR gamma meter was used.
2.2.7 Air Samplers. One high-volume (50 cfm) air sampler was installed on each of the
smaller barges, and two were installed on the large barge. Each sampler used a 4-inchdiameter GM-2133 filter. The intake airspeed of 8 knots was expected to nearly match the
surface windspeed during the sampling period. Air samplers were alined to face into the
prevailing wind. Figure 2.15 shows an air sampler station.
2.3 OPERATIONS PLAN
2.3.1 Weather Requirements. The limited amount of instrumentation available for meas~urement of fallout in the lagoon was placed in an array oriented for the prevailing wind
direction, +10°. It was required that winds at shot time have the proper direction to assure that the fallout pattern would not miss the array. Windspeeds were restricted to 20
knots or less to assure that a reasonable percentage of activity would be sampled. Project
34.10 provided the preshot wind data necessary for the H-hour precision.
Additional requirements were that there be no rain for at least 2 hours postshot and that
no cloud cover that would interfere with balloon tracking and shot-cloud photography.
2.3.2 Remote Area Monitoring System. The two RAMSwereactivated by H—1 hour and
operated continuously until the dose rates had fallen below significant levels. RAMS station operators transmitted readings periodically to the control point at Station 1520 to per~
mit early calculations of the fallout phenomena. The sled-mounted RAMS werepulled into
the crater by H+ 10 minutes.
2.3.3 Land Recovery Parties. Land recovery parties entered the field starting at H+'/
hour. Reentries were made thereafter at a rate calculated to secure complete data at
the earliest possible time without overexposing available personnel. Each recovery party
comprised at least one project monitor and one Rad-Safe monitor. A simple procedure was
developed to permit early recoveries with a high probability that personnel would not receive more than an allowable radiation exposure dose. The procedure required controlling
the total time spent by a party in the field and limiting penetration to fields of less than a
maximum dose rate. Dose rate was determined by the time required to perform a recov~
ery mission and the available dose (that dose which each person in a party may receive and
not exceed AEC tolerances).
Each recovery party was assigned a maximum time required for a specific recovery
mission. With the available dose known, Table 2.3 was used to find the maximum-doserate field that a party was allowed to enter. Personnel would proceed directly into the
21
-
-