Preliminary Report, Operation Plumbbob. Project 2.9, Nuclear Radiation Received by Aircrews Firing the MB-1 Rocket

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at. 163 81 215 copies, ttritr A NEVADA TEST SITE DECLASSIFIED WITH DELETIONS HEAD OU ART tRS.fttlD COMMAND. ARMED FORCES SPEC IAI WEAPONS PROJECT

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T U ia a prellminary report based on all data available at the close of thie project's participation in Operation PLUMBBOB. The contents of this report are subject to change upon cornpletionof evaluation for the final report. This preliminary report wfll be superseded by the publication of the final (WT) report. Conclusions are recommendations drawn herein, if any, are therefore tentative. The work ia reported at this early timeto provide early test results to those concerned with the effects of nuclear weapons and to provide for an interchange of information between projects for the preparation of final reports. When no longer required, this document may be destroyed in accordance with applicable security regulations. When destroyed, notification should be made to AEC Technic& Information Service Extension Oak Ridge, Tenn. DO NOT RETURN THYS DOCUMENT

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NUCLEAR RADIATION RECEIVED BY AIRCREWS FIRING THE MB-I ROCKET Kermit C. Kaericher, Capt, USAF Air Force Special Weaponr ?&er Kirtland Air Force Base Test Group Director. Pmgramr 1-9

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mcket ami were i~firum&d to aaemure &e total gamma .ndneutmn exprure reoeived by tbe dmrew memberr. Neutron dose waa meamred by fledon-foil detetotorr, gold d rplfur threrrhbold dobcbrr, chemical dosfmeterr, md the Lo8 Alpmor human countar. Gamma radiaflon Olmmr dow rater were ddo meamred in aa initlal-grmmr-verru-~morder thpt bad bmm bmtalhd in tbs aircraft. Complete data ami up rrrplyeie thereof appear in RRhterpreted in order to yield the met reliable esti.mrts of the total srpo.lwr. Them -re then aomparai with valuer predicted on the hrrir of prevloucr hrll-wrle nudear tatst Neutron md ~ a m o udoser did not ear~eed5 rep and 3 r, reepatlvsly. Neutron eqmaurer aompared we11 with the predicted d w r , whereaa gamma eqmrurar were f o u d to bo mmewhat lower thn the predioted d u e r . Part of the lrtbr Mereme can be a$Mbuted to shielding by the airframe. oraft a! an altitude of 19.000 femt M8L with a radiation dore to the delivery airmew that There is no doubt that an MB-1 rocket o m be fired from aa F-69 interoeptor air-

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Thir report presents the PreliminaFy results of one of the 43 projects comprising the Military Effect8 Program of Operation Pl qb bob, which included 28 test detonations at tk Nevada Test Site in 1957. For overall Plumbbob military-effects information, the reader is referred to the includes: (1) 8 description of each detonation,.including yield, zero-point location and environment, type of device, ambient atmospheric conditions, etc.; (2) a discussion of project results; (3) a summary of the objectives and results of each project; and (4) a lirting of project reports for the Military Effects Program.

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The MB-1 rocket h.beooma aporatiozully available to the Air Dofenre Command of the would be rubfecbd. nuclear warhead. Only limitad Idormatton waa avallahle from part bat o p rWRmOM

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The octivitiee of this project wetre limited to Shot John, which WBB ths MB-1 rocket bet. Modfn ~ ati ~ ~to the rireraft required for ths Mati on of the hat wm n to were made by tho 41925th Teat Group (Atomia) mveral we#ks before the aatual bet. The ln6trumenta thomrdlveo were installed during the night prior to the bet. Atter tho detonation lurd the mtum of the aircraft to Indian AFB, all inatrumenb were removed at the earlieat poarible moment. The fieelon-foil neutron detectore a d neutron threahhold datators were flown immediately to the aountiag frcilftie8 errtrbllohed at tho Nevrd. Teat Site by Project 2.3. All of the fission foil8 were counted at least onae by H + 58 minutes. Tbe crews of the dellvery and alteraate delivery aircraft were flown b to1 Alunoa Saientific Laboratories (LASL) for counting in the human counter. Thie aouating waa rrccompllehed lakr time. The chemical doalmetorr were read by Project 39.5 during the afternoon of d o t day. The National Bureau of Standarb (NBS) film packs were returned to Air Force Special Weapons Center (AFSWC). They were proaeeeed and Interpreted on ehot day. ahwyslrr during the afternoon of ehot day. The three aircraft that participated in the MB-1 delivery wetre instrumented. kbntlcal oeta of instruments wem fnstalled in four locations on each aircraft. Ia the dellvery and alternate delivery sircraft, them four 10cati0~were the rear aockplt, left and right wbgUp hake, and tall section of the fuelage. In the hlast-effecta aimraft, they were the rear cockpit, rlght wlng-Up tanlr, tail mation, a d mae aecUon of the fuelage. Each pilot and radar obeerver crvried an NBS film badge, a --Safe film badge, and a set of Cbemfcal doelmetera in the pocketa of htr flfght suit. -&a that reaorded gamma dose rate as a function of time were installed in each airoraft by Project 2.5. A detalled gamma-time hietory, M well ae a dscurraion of predicted grrmmr dooeo for the dellvery airataft, io reported in -91414. thio project was to measure the radiation exposure of the flight om-. l'hdditional iaaFumsnt l o c a t i o ~were choeen in PZI attempt to gain soma hformrtion on the degree of rrhieldtng afforded by the airframe. detaatoro, an well ao the aetmioted aouptlD9 ppparatu~~,were aaUbr.bd at LASL prior to ths beginning of the toot operation. Detrilr of this crllbratfon aaa be found in ReferAvfatlon Mediche, Randolph Fie1 Inaemuch an no time limitation exieted, the other instruments were evaluated at a The location of primary intareat WBB the crew oomputmmt, dnce the objeative of Chemical doofmeters were obtained from Project 39.6 through tho WAF Sabool of Texas. For the pnxpooe of mixed irradiation doelmetry,

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aystsm yielded the g a m ~and fast-mu-n &#e, whfle the half-ldwe ayetem yielded the gamma dose only. Some of these dosimeters‘wereplaced in lithium shields fabdcated independent of energy down to h u t 90 kev and to eliminate the reaponse to thermal Detalls of tbis calibration n d further infonarrtlon on the functioning of the dosirnetere 6tandard types of personnel film-badge dosirnetere were used to m~asurethe gamma-radiation exposure. The National Bureau of StarrdaFde fllm badgem were obtained from Project 2.5. These were calibrated with gamma radfatlon from a IO-curie Corn murce at AFSWC. Rad-Safe film badges were furnished by the Nevada Teat Site Rad-Safe Orgpnizatlon. The expoeurer recorded by the Radspte tilm bad@3e are reported as the ook Ridge N a t i d Laboratories. The purpoee of this wan to render the dosimeters returned by the unit at the test site. TbA &crews from tbe delivery and alternata delivery aircraft were flown to LASL within 5 hours after the time of detonation for countbg in ths wholedody counter operated by the E 4 group of LASL. By measuring the induced gamma radiation from Naa in the body, thts operetion giver a meaaure of the neutron curposure~. A background level for the radiation emitted by each crew member had been eetahlished by a count taken 6 weeks prior to rhot day. This background level doer not change sppreciably over a period of several months. At the time of the postehot counting, each individual was also scanned that any increase in gamma radiation emitted by the body was from Nau and not from. fission-product contamlnstion,either external o r internal. Details of the construction, calibration, and use of the Los Alms human counter can be found in Reference 6. a cry* rcintillation counter. The spectral analysis from this operation made certain 2.3 DESCRIPTION OF REQUIRED DATA neutron exposure aa meaeukd by the instruments and devices described in the previous For both gamma and neutron measurements, the reliability and accuracy of the data depend on the magnitude of the expoeure. Film measurements of gamma radiation are normally considered to be accurate to h20 percent. The chemical dosimeters furnished by Project 39.5 are accurate to +20 percent for gamma esposures above 5 r. They are not sufficiently o e ~ f t i v eto measure exposures below this value. Tho threshhold for neutron measurements using chemical doairnetera is about 10 rep. Above this level they are reliable to t20 percent. Fiesfon-foil detector8 for faat neutroae have a lower limit, which ie dependent on the amount of euposure and the time betwwn eqosure md evaluation. For the present case, thir lower limit m about 5 tep. The thermal-neutron threehhold detectore w i l l me88u.m are accurata to i20 percent, but they a m not tu3able below these limits. d & r d accurate to withfn a factor of two. This level of cootldsn<le m a y be improved by more-exbnslve cdibration of the counter, but thie months. This method of measurement has the unique capahillty of debttag fast-neutmn esposurer of ths otder of nsgnltude of 0.1 rep Md 0811 be conaldercsd to be the best method presently avpilable for the evaluation af rmall neutron exposures, m special methods or devices wem used to record, redme, or correlab a data. me data required for purpose of this project conefeted of the total gamma aad not be^ completed for several Since dl of the inetnrmenta were amenahle to poutuhot evaluation sld inbrpretotton,

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New Mdco ; Secret Ftartrlated Data. Secret Bsrtriotsd Data. Ldmrrtory, Edged, Marylaad; Secret Remeted Data. 99.5, Operotion Plumbbob, ITR-UM, Auguet 1957, Oak Ridge Naiionsl Lnbontoriee, olrk Ridge, Teanerreb; -rat Ehsbfcbd Data.