Senet ee 302 a TRANSURANIUM ELEMENTS IN SAMPLES COLLECTED NEAR BIKINI ATOLL the alpha-acuvity ralto of these nuclides tn The position where the “Sth Fukuryu-Maru”™ is shown as a daughter nuclide of 7 Pu. analyzed in this study were collected in 1973 selssa show the weight of a sample required to detect Idis/min of other nuclides in the sample which contains 10 dis/min/mg of ?’Pu. of Tokai University. Accurate latitudes and longitudes of these locations are given tn the debris, as shown in Fig. Ib. For mass number 241, the calculated activity of “'Am Furthermore, the values on the upper ab- MATERIALS A 6me sample of “Bikini Ash” was obtained from the 70-mg sample stored in the Institute of Physical and Chemical Research, Japan. In this present study, made in 1974 ~ 1975, 2meg of the sample was submitted for analysis of 7?"pu and “Am, and 4 mz of the sample was used for tow energy photon spectroscopy. I was found by its spectrum, shown in Fig. 2, that 7°**"pu, “Am, '? Eu, MCs and Sb were contained in this sample. was exposed to this explosion debris in 1954 is plotted in Fiz. 3. Marine sediment samples hy a marine research vessel, the “Tokai 1” Table 1] together with water depths, topographies of sea bottom, and the characteris- tics of the sediments. All sediment sumples were collected with a dredger. The samples are identified as 73105, 73108, 73109 and 73113 as shown in Table 1. One gram of cach sample was dried at 110°C and used for plutonium and americium analyses. Sample No. 73113 contained manganese nodules, which were removed before analysis. METHODS An aliquot of “Pu and '“Gd. solution was added to the samples as yield tracers for a Ray-activity «x idpyr Idpmn* Idpmen | dpd I dph _ ( oeoto!oROoo Pn da tor uy asat O-+O-+Oa eonsdue asa 2521} OOOO a6 ame + 252b J O-O-0+0-0-0+b wre de a 6s wey ; POOes os eraev 250- C}--O—-1- oCOe 2507 L. as oem wind 4 N A | 2487 r 2?46F C+D tte Qa 30 Mey 4 246k r C+ O—- D8 v2, 93 36 way 4 F os 18 wy 4 aaah Chee OE! 06 ot uy 2424 Peete! |. BOR 240Fr Ce Beco L POO LfOe30=APA ot, 2368- O io, 92 J aaah 4 90 wey a8 ae way 4 + 242) L OS 17 Maw a 240 a 13 wey , , , , ' ' 95 94 35 Se 30 ch 4 Lg BS T T T ¥ Oo rt T tng i* 4 1 ‘ x x 4 9 x ! 71 o Ox x Ox 7 7 3 1 Ox x 4 0 oO 4 x 4 Ox 4 @ 4 | A Jo 10 10° 10? 10710? 10® 107 10% 107 10" 10" Relative abundance O fa) Zz {b) Fic. ta. Nuclear reaction sequences for the production of heavy nuclides by thermonucle: ir explosion, b, Relative abundanceand alpha-activity ratio of heavy nuclides in the immediate debris of the “Mike”. ASE7S | x x oO 411 10 tt xf gM | L 4 . oO F Hf tt00%) F [J—-O- OC} +f oe T oo [ - BO+0-O- 0-08 160, O53 Bittey +4 248+ O--O-+-+ Oe T Lofton (Kg