we _. — UNGUYSSFED | being provided with a totul radiation dosage indicating device which would cover a range of frar about 200 to 1000 roentgens. Additional 1 desirable features of such devices would be that they should be light, cheap, require no up-keep and be capable of being read easily by relatively inexperienced personnel and with a minimum of awciliary possibilities of fulfilling the need outlined above, wee ee Although this work was in the most prelimimry plinses of development it seaned advisable to request that a project be proposed to test this method of measuring; radiation dosaye, Therefore, the project was submittal and approved along with other Bureau of Ships projects. when approval was received steps were taken to obtain suitable crystals for the purpose, Dr, Friedman was contacted and though security considerations did not permit disclosure of the immediate purpose for which the crystals were desired, a tentative promise of . This method seemed to offer tee ee ne ee ae ee Re enape # a e men e of crystals of several compositions. . Research Laboratory published a report on the coloratian by X-rays . In the latter part of 1947 Dr. Herbert J. Priodman of the Naval eo | ’ equipment. about one hundred crystals was received. The crystals which had been tested previous to this project were comparatively bright in color, ' It was believed that if sufficient— m™ ly larce crystals were grown, adequato coloration could be produced for visual checking of doses. These mterials are subject to fading when exposed to ultra-violet light, therefore it was necessary to pockage the crystals in a small aluninun tube. Because of the Linited tine available no calibration was feasible prior to departure from Washington, - 33 - co. es creer ee . Mt a ate hh eas eel: ak ae a ‘ ~ me ' auhenears 4 SEEAEaoaSa Be ST i lon etot be * m eS « ”