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FINAL REPORT OF OFF-SITE SURVEILLANCE Southwestern Radiological Health Laboratory Department of Health, Education, and Welfare Public Health Service National Center for Radiological Health This report was prepared as an account of Government sponsored work. Neither the United States, nor the Commission, nor any person acting on behalf of the Commission: A. Makes any warranty or representation, expressed or implied, with respect to the accu racy, completeness, or usefulness of the information contained in this report, or that the use of any information, apparatus, method, or process disclosed in this report may not infringe privately owned rights; or B. Assumes any liabilities with respect to the use of, or for damages resulting from the use of any information, apparatus, method, or process disclosed in this report. As used in the above, "person acting on behalf of the Commission” includes any em ployee or contractor of the Commission, or employee of such contractor, to the extent that such employee or contractor of the Commission, or employee of such contractor prepares, disseminates, or provides access to, any information pursuant to his employment or contract with the Commission, or his employment with such contractor. Oak Ridge, Tennessee This surveillance performed under a Memorandum of
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This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency Portions of this document may be illegible in electronic image products. Images are produced from the best available
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Project Longshot was an underground nuclear experiment conducted on Amchitka Island in the Aleutian Island Chain, on October 29, 1965 at 1100 hours AST. Part of the Vela Uniform series. Project Longshot was designed to gather additional information on seisrpic waves generated by an under - ground nuclear detonation. Under a Memor andum of Under standing between the U. S. Atomic the PHS conducted a program of radiological monitoring and environ mental sampling along the Aleutian Island Chain, and at selected loca tions on the Alaskan mainland.
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On the day of the event, nine monitors were standing by at the locations listed in Table 1. Additionally, one PHS staff member was at the Amchitka control point and three PHS personnel were airborne in the Amchitka area. A PHS Medical Officer was stationed on a U. S. Coast Guard cutter which was patrolling in the vicinity of Amchitka Each monitor was equipped with aa Eberline E-500B survey in strument and a Victoreen Radector Model AGB-50B-SR. The Eberline E-500B has a range of 0 to 200 milliroentgens per hour (mR/hr) gamma and beta-gamma detection in four scales with an external halogen filled GM tube and a 0 to 2000 mR/hr gamma only range from an internal Anton 302 tube. The Radector has a range of 0. 05 to 50, 000 mR/hr gamma and beta-gamma on two scales. This instrument employs an inert gas ionization chamber. Errors associated with readings from these instruments are on the order of +20%. Table 1. Ground monitor locations, Project Longshot. Location Number of People Adak Is land 1 Anchor age, Alaska 6
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2. Aerial Cloud Tracking Aerial cloud tracking was performed by a USAF C -54 aircraft and crew with, a three man PHS monitoring team. Instrumentation for monitoring included two Precision Model 111 Radectors. The probe of one of the Eberline instruments was mounted in the hole below the cabin compartment in such a way that there was only one layer of airplane "skin” below it. The other instruments were mounted inside the cabin of the aircraft. In addition to the survey instruments, a multichannel pulse height analyzer was installed in the forward portion of the cargo com partment. This system included a multiscaler read-out on a strip chart and a single channel analyzer with a scaler read-out. The detector used was a 3- by 3vinch Nal(Tl) crystal with a 3. Film Badges and Dosimeters On the day of the event, sixteen EG&G thermoluminescent dosim eters (TED) and 25 DuPont 555 film badges were placed at three film badge stations or worn by ten PHS personnel. (See Table 2) The DuPont type 555 film is accurate to +50% in the 30 to 100 mR rangei and +10% in the 100 to 2000 mR range. The lower limit of The EG&G Model 2 Thermolumiaescent Dosimeter System is a wide range gamma dosimeter system consisting of the dosimeters, and EG&G-designed electronic reader, and a light standard for system calibration. The dosimeter exposure is read out and automatically recorded as a permanent chart record.
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The TJLD System is based on the thermoluminescent properties of manganese-activated calcium fluoride. A layer of this mate - rial is bonded to a helical heater element which is positioned in an evacuated glass envelope. The active material "stores" a small amount of the incident radiation by trapping electrons in the high energy levels. The stored energy is released by heating the active material. The released energy, in the form of light energy, corresponds to the dose received and is converted into an electrical signal for the chart recorder output record. Manufacturer's specifications for this system are as follows: Energy Independence +10% from 60 Kev to 1,3 Mev +2 mR or 15% of scale read ing, whichever is greater Graph on perforated 6 inch strip chart recorder Table 2. Dosimeter and film badge locations.
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On the day of the event, 19 Gelman "Tempest" air samplers were operating at locations listed in Table 3 and shown on Figure 1, Also shown in Figure 1 are the permanent sampling stations of the Radiation Surveillance Network administered by the PHS in The "Tempest" air sampler used by the SWRHL employs a Cast Model 1550 vacuum pump driven by a General Electric 1/2 horse power motor. The pump runs at 1440 rpm and draws an average flow rate of approximateiy 10 cfm. The sampler is equipped to use a 4-inch diameter filter paper and an MSA charcoal cartridge. Thei Air Surveillance Network employs Whatman 541 filter paper for routine air sampling. The total volume of air sampled is calculated from an average vacuum reading (which in turn indicates the average flow rate) and the total time of sampling. All air sample prefilters and charcoal cartridges were returned to the1 Southwestern Radiological Health Laboratory in Las Vegas for radiological analyses. Prefilters were counted for gross beta) proportional system which has an efficiency of approximately 45% for 0. 54 Mev betas. After an initial count, if no significant activity was detected, the prefilters were counted at 5 and 12 days after collection. All charcoal cartridges were analyzed for gross gamma only, and the results compared with normal background cartridges col lected at Las Vegas.
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Table 3. Air sampler locations and operating periods. Port He id e n
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□ TEMPEST AIR SAMPLER NOME A PERMANENT R.S.N. STATIONS in = approx. 140 miles INSET ALEUTIAN ISLANDS
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2. Milk, Water and Vegetation Samples No milk, water or vegetation samples were collected specifically for this event. ■ II. PUBLIC RELATIONS An extensive public relations program was carried out in the two weeks prior to Project Longshot. ^ Off-site personnel made appearances before civic groups, and movie exhibitions and informal discussions were conducted on mainland Alaska. In addition, closed circuit television interviews were held at military installations on several of the Aleutian Islands. All radioactivity was completely contained during Project Longshot. No prefilters or charcoal cartridges showed any values above back ground levels. All TLD's were within background ranges, and all the film badges processed showed no exposures above the limits of Project Lpngshot produced no radioactive exposure to any off-site