TM 5-6635-386-12&PNOTEPlace the source rod in SAFE position and besure the tester is at least five feet from nearbyobjects.Stand the shipping case on end and place the referencestandard across the protective strips on the case Threebuttons on the reference standard fit intoaccommodating depressions in the bottom of the tester.See Fig. 1-2.At this point two counting methods may be used:Manual, with successive counts.Automatic, with four minute averaging.The Manual method is used for periodic tester evaluationper Para 1-9.The Automatic method is used for routine daily standardcount accumulation into the tester Standard CountMemories.Manual methodSuccessively accumulate 10 1/4 minute counts.Do NOT use other time periods for purposes ofevaluating tester performance under this program.Proceed to Para 1-9.Automatic methodPress STD and LOCK simultaneously on the keyboardand the tester will now clear all four memories, and willcount a 4 minute count into all four memories. The 4minute count will be normalized to a 1/4 minute commonbase for ease of subsequent computations.Record the final average of either method on the dailyfield work sheet. The 4 minute automatic standard countwill be retained in memory until erased by the next STDor by the taking of a TEST count.1-9. TESTER EVALUATION USING MANUALSTANDARD COUNTPeriodically, the tester should be checked for goodstatistical operation. This is the ONLY way the operatorcan verify that his tester is operating correctly. Using thistechnique, it is possible to predict a future failure before itis severe enough to cause field errors or completebreakdown. This periodic evaluation should beperformed at least once a month or whenever the testerhas not been used for several months.All nuclear method testers will vary in count rate fromone undisturbed count to another due to the randomnature of the radioactive source decay.This is a very reliable random rate in that it faithfullyobeys the laws of statistics relative to random sources of"population’...wherepopulation=countratefor nucleartesters.Given:Any series of numbers taken among a varyingpopulation of events will exhibit a form ofstandard deviation.A series of nuclear tester counts, taken withthe tester in an undisturbed position betweenall counts, will also exhibit a standard deviationaround the average of the counts or mean.Given:It is true that if the source of a series of eventsis truly random, then the standard deviation of1-9
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