Intercomparison of the medium energy primary standards for X-ray exposure of NPL and ENEA, Italy Moretti, C J; Heaton, J A [National Physical Lab., Teddington (United Kingdom). Div. of Radiation Science and Acoustics]; Laitano, R F; Toni, M P [ENEA, Casaccia (Italy). Centro Ricerche Energia] 61 RADIATION PROTECTION AND DOSIMETRY; X RADIATION; CALIBRATION STANDARDS; INTERLABORATORY COMPARISONS; IONIZATION CHAMBERS; RADIATION DOSES; RADIATION QUALITY; 560190; RADIATION PROTECTION STANDARDS An intercomparison between the primary standards of exposure for medium energy X-rays held by the National Physical Laboratory (NPL) and ENEA in Italy is described. The intercomparison, using four different transfer chambers, took place at NPL in December 1989 and at ENEA during March 1990. Measurements were made at four therapy-level qualities, with half value layers of 0.15, 0.5, 1.0 and 2.5 mm Cu (nominal generating voltages of 100, 135, 180 and 250 kV respectively). At the 2.5 mm Cu HVL quality the primary standards were found to agree to within about 0.8%; for the other three qualities the chambers differed by no more than 0.3%. (author). National Physical Lab., Teddington (United Kingdom) OSTI; NTIS (US Sales Only); INIS United Kingdom 1991-04-01 English Technical Report Other Information: PBD: Apr 1991 Medium: X; Size: 16 p. https://doi.org/ ON: DE92626192 [] NPL-RSA(EXT)-18 Other: ON: DE92626192; TRN: GB9200573035337 GBN; SCA: 560190; PA: AIX-23:035337; SN: 92000725444 2008-02-12 10139701