METHOD FOR DETECTION OF GAMMA-RAYS RESONANCE ABSORPTION OF LONG-LIVED NUCLEAR ISOMERS

FIELD: physics. ^ SUBSTANCE: in series of experiments related to observation of gamma-rays resonance absorption of long-lived nuclear isomers, in particular 109mAg isomer, probability of Moessbauer gamma-ray self-absorption in source substance versus temperature has been used. Desired effect cannot be observed at indoor temperature and at liquid nitrogen temperature, but it can be observed at liquid helium temperature. As far as in this case relative reduction of registered gamma-rays intensity due to Moessbauer absorption is negligible (~10-3), so deformation of inner parts of cryostat constitute big danger for correct evaluation of desired effect because such deformation can take place at temperature change and lead to change of distance from source to detector. To shun danger it is suggested to detect effect of gamma-ray quantum absorption by means of external magnetic field direction that influences on the source. In real conditions such field can be geomagnetic field splitting gamma-ray line of long-lived nuclear isomer into number of components divide by gaps that exceed their natural width many times. In virtue of the latter resonance absorption of each emission line component can take place only within width limits of the same emission line component. It leads to strong dependency of resonance absorption on angle between magnetic field direction and direction, in which gamma-ray quantum is registered. While registering gamma-ray quantum on horizontal direction after temperature mode setting and completion of deformation processes, it is suggested, to compensate periodically vertical component of geomagnetic field and to observe synchronous change in registered gamma-ray intensity. This change can constitute quite observable quantity. In particular in case with 109mAg isomer relative change of speed will correspond to change of possible resonance cross-section per 60%. ^ EFFECT: method for detection of gamma-rays resonance absorption of long-lived nuclear isomers. ^ 1 dwg В ряде экспериментов, связанных с наблюдением резонансного поглощения гамма-лучей долгоживущих изомеров, в частности изомера 109mAg, использовалась зависимость вероятности мессбауэровского самопоглощения гамма-лучей в веществе источника от температуры. Искомый эффект не наблюдаем при комнатной температуре и при температуре жидкого азота, но становится наблюдаемым при температуре жидкого гелия. Поскольку и в этом случае относительное снижение регистрируемой интенсивности гамма-лучей