and I instruments. Pot readings were taken concurrently and were used to fill the gaps in the Mark I, I, and UI measurements. At three stations, 1, 2, and 6 (Figure 2.6), vertical casts were made electronically by lowering the Mark If instrument to a depth of 250 feet and recording its readings as a function of depth. In two instances, this instrument passed through the contaminated layers and into the uncontaminated water beneath, thereby giving the extent of the mixing directly. A trial showed the need for a 150-pound weight attached to the Mark II to keep tor pope T eee NOTES SOLID LINES- Mork tl calibration ogoinst distont point source of Radium ot Site Elmer, IO MAY 1954 The ray in- adence was normal to the poo. instrumentS axis (Block letters ind:cote the instruments amgiificat I jon ranges) 30! DASHED LINE- Mork 11 calibration against point oe source of Radium of U.S.N.B.S several weeks icter The ray incidence here agcin wos norma! to the instrument's axis Descrepancy between A ond the dashed curve may be due to the battery voitoge MR, HOUR change or to the error in source evaluation, note, however, thot if ts small tor + - Points within Large Circle- Computed overall sensitivity of Mork ti when used submerged in water which is contonr inated with the follout products + ——#- whose spectrum is thot assumed for the computation. This sensitnity was computed for use only of the instrument's scote-point of 19 microames For the purposes of this final report,in situ mten‘sities were therefore derived by Multiplying the intensities given by the solid curves by the factor 15 (See Appendix B) en] —_— ° ” 20 30 ‘0 MICROAMPERES Figure 2.3 Mark II Calibrations. the hydro wire more nearly vertical. Depths were read on the meter wheel of the hydro wire. Unfortunately, the electrical wire was not long enough to follow the descent of activity to its ultimate depth. 2.2 WATER SAMPLING Water samples weretaken fromboth the surface and vertical casts in the survey after Shot 5. Only surface samples were taken after Shot 6. All samples were air-shipped to NRDL for analysis as quickly as possible after they were taken. For Shot 6, duplicate samples were taken everywhere; analyses were carried out both at NRDL and at NYOO, AEC. 2.2.1 Sampling Devices. Surface-water samples were taken from a bucket passed over the side while the ship was underway; either a plastic or glyptol lining was used in the bucket. Two kinds of sampling devices were used to take the water samplesin the hydrographic casts. Standard new Nansenbottles were used at a minimum of four depths simultaneously. 21