TY - JOUR
AU1 - Kegerreis, Roy
AB - A Portable Apparatus for Measuring X-Rays 1 Roy Kegerreis Ann Arbor, Michigan ↵ 1 Read before the Radiological Society of North America, at Kansas City, December, 1924. Excerpt RADIATION therapy is very much in need of practical methods for comparing the output of different X-ray machines. It is essential that every installation be checked up occasionally so that its users may have assurance that the output is constant as well as know how it compares with the installations of other workers. Quality and quantity are the things about which a testing apparatus for X-rays should give data, since they are used for the comparison of different installations. Only a method which measures the terminal, or end, product can be employed to give unimpeachable data for determining such factors. Depth dose for specified conditions of aperture and distance, when once worked out for some one effective wave length, always remains the same for that equivalent spectrum. That is axiomatic. Consequently any apparatus which will give data for securing the quantity and effective wave length will then serve for determining the depth dose, when the so-called Dessauer charts are given for effective wave lengths—as they should be. This instrument has been assembled to provide an easily portable means for such comparisons. Its design and construction involve many complicated laws of the physics of X-rays and electricity; its working parts, however, are so arranged that thoroughly reliable readings for tests on X-ray equipment can be made by persons entirely uninformed about the factors which influence the details of its design. Different sized apertures and variation of intensity with target distance are used to adapt the testing outfit to any sort of X-ray tube, no matter what its output may be. The relative absorption of different filters is used to get at the effective wave length or spectral qualities of the rays being tested. The entire apparatus is contained within an aluminum cabinet of about the same general dimensions as an ordinary suit case (Fig. 1). All parts are securely fixed in place except the ionization chamber, which is permanently fastened to a fifteen-foot armored cable and may be lifted out of its compartment (Fig. 2). All the circuits of the apparatus are completely surrounded by a metal sheath which protects it from induced static disturbances or other similar effects. The apparatus weighs forty pounds, the greater part of which weight is due to several 22 1∕2-volt elements of signal corps type “B” batteries, sue as are used in wireless work. This source of direct current was chosen so that there might be absolute independence from all outside influences, as well as simplification in the operation. A small direct current voltmeter with a resistance in series with it serves to indicate the voltage which is impressed on the system. The resistance is placed in series with the voltmeter in order to lessen the current taken from the battery. Copyrighted by the Radiological Society of North America Inc.
TI - A Portable Apparatus for Measuring X-Rays
JF - Radiology
DO - 10.1148/4.6.497
DA - 1925-06-01
UR - https://www.deepdyve.com/lp/radiological-society-of-north-america-inc/a-portable-apparatus-for-measuring-x-rays-iIUwZo1Fst
SP - 497
VL - 4
IS - 6
DP - DeepDyve
ER -