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Special state standard of bremsstrahlung energy flux unit in the maximum photon energy range 0. 8 to 8. 0 pJ (5 to 50 MeV)

Journal Article · · Meas. Tech. (USSR) (Engl. Transl.); (United States)
DOI:https://doi.org/10.1007/BF00822527· OSTI ID:7326563

In the special State standard the bremsstrahlung unit is reproduced in watts on the basis of calorimetric and ionization methods; the use of two different methods improves the reliability and widens the range of the unit reproduction. The standard makes it possible to reproduce the energy flux unit in the range from 10/sup -4/ to 10 W depending on the bremsstrahlung source employed, with an rms deviation of the results less than 1 percent and a systematic error remainder of 5 percent. The standard consists of an isothermal differential calorimeter, quantometer, monitor chamber, and recording apparatus. The bremsstrahlung photon source is a type B-50/50 betatron of the Institute of Metrology. The photon beam, formed by accelerated electrons on the accelerator target, passes through the wall of a porcelain vacuum chamber and through the walls of the monitor chamber whose total thickness is equivalent to 4.2 g/cm/sup 2/ Al. A set of cylindrical lead diaphragms 300 mm long and with 5 to 60-mm apertures is used to shape the radiation beam. The diaphragm is followed by a permanent magnet so that electrons formed in the diaphragm do not reach the monitor chamber. The measuring console PIKI-1 is located in a room separated from the experimental hall by a concrete wall 100 cm thick. The console contains the entire measuring equipment for calorimetric and ionization measurements. The calorimeter measuring circuit consists of a dc bridge whose arms are formed by a resistance box, a standard resistor, and thermistors.

OSTI ID:
7326563
Journal Information:
Meas. Tech. (USSR) (Engl. Transl.); (United States), Journal Name: Meas. Tech. (USSR) (Engl. Transl.); (United States) Vol. 19:3; ISSN MSTCA
Country of Publication:
United States
Language:
English