SU1450144A1 - Method of measuring the effective size of focus of x-ray source - Google Patents

Abstract

The invention relates to the field of X-ray technology and is intended to measure the size of the focus of an X-ray source. The purpose of the invention is to increase the information content. The projection shooting of the focus is carried out using a set of x-ray films arranged one behind the other with attenuating screens placed between them. 4 il.

Description

j The invention relates to an x-ray machine and is intended to change the size of the focus of an x-ray source with

 The purpose of the invention is to increase informativity.

Fig. 1 shows a schematic implementation of a method for measuring the effective amount of focus of an X-ray source of Joro radiation; FIG. 2 shows a cassette with X-ray films and is absorbed by them with screens, a section; per fng. 3, the curves of the change in the effective raem of the focus of X-ray tubes 15 C, 3 BPBB-150 and BSV-17, depending on the thickness h of the absorbing material; 1-a FIG with A - curves of change. the size of the focus of the x-ray tube 0.3 BGgeb 150 B is dependent- 20 And on the thickness h absorbing 4; go material a- .AA with active settings of high 1 Apr.

j The method is carried out as follows: lUsoM, 25

I Camera 1 with input aperture

Stop with respect to the axis of the resize if eHOBCKoro beam at a distance L) ft of the focal spot F at the anode 2; of an antigen tube, and a cassette 3 with zg x-ray films 4 and strips ™ Data between them with attenuating fkr. channels 5 - spaced kg-n L from the bottom — fragments of chamber 1, aperture diameter 1 n : 3x is the ratio of the meshch1, in itself choose - b depending on the size of the effective focal point of the site

one

In the process of transmission of the beam

Zekovskiy radiation from the focal n t-40 (; "F anode 2 source sources from the diaphragm-iSiy camera 1 image; focal spot F is projected onto the cassette 3 with x-rays with films 4 and filled with all films simultaneously, 45 lably from films to the film during the projection of weakening screens 5, covered with films, the exposed films 4 are processed under the same conditions, photometry the image of the focal spot on each film in the same direction, plot the graphs rasregGelenil square - 1 blackness of the image of the focal length and PS for this image: on phototagging; 11, the size of the image of the focal spot on the film is measured using 1 black light density distribution, the true value of the size of the effective focal spot is calculated, taking into account the size of the image of the focal spot F on the film, the diameter d of the hole of the diaphragm fy and the K-ratio increase in the ratio

F

er - - -

where K La / b ,.

Fig. 3 shows the dependences of the change in the effective focus size for Oj3BnB6 150 tubes with an acute intensity distribution on the focal spot (curve 6) and EBU-17 with a practically uniform intensity distribution on the focal spot (curve 7) with an absorbing material thickness of up to 4 mm crajm or O, 92 NM lead. The trz foci foci are removed on a cassette with 12 Sgrukturiks D-7 films with lead gaskets between them with a thickness of 0.03 mm with a total thickness of gaskets between O films, 88 mm. Equivalent 0.04 mm lead absorption is provided by X-ray film material.

Dependent. -And given on obtained at a voltage of 70 kV. As in the case of fcg, 35 the size of the effective foxy spot of the p-ZgCH P source, at a voltage of up to 70 kV, sharply increases in three times non-oscillatory absorbing material (1.0 1.5 steel), and later on The size of the kenne is insignificant, which is especially pronounced for an x-ray tube with an almost inhomogeneous distribution of the interatism of x-rays and over the surface of the focal spot

When calculating the true size of the size of the eF4) eV: tiBi focal spot on the plate, the change in the magnification factor depends on ... and on the thickness of the film cassette. For example, thick cassettes with films and pads between them were weakened, and they shielded 10.5 (12 films - 70 kV) and 2t mm (20 films 100 kV) with screens. Poet koeffshdie.N uvepi cheni); equal to the first film K - L2 / Lj5 and s. an ectc (increased) and for the last films is zem

mask

L2 + 10,5 j - - -

i

LI + 21 mm -L;

10.5 and 21 mm thick.

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Compiled by K. Kononov Editor G. Volkova Tehred L. Serdyukova

Order 6979/56

Circulation 832

VNIIPI State Committee for Inventions and Discoveries at TKST of the USSR 113035, Moscow, Zh-35, 4/5 Raushsk nab.

Production and printing company, Uzhgorod, st. Project, 4

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Proofreader M.Maksimishinets

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Claims (1)

Claim Method of measuring the effective size of the X-ray source focus, comprising pro1 ₀ ektsisnnoy shooting Focus source using a pinhole camera, measuring the size 'of focus in the acquired image, and calculating the true focus size considering geometric para15 meters shooting, characterized i in that, for the purpose increase the information content, projection focus shooting produce a set of sequentially arranged along the beam films placed between them weaken known screens · tal ^l of tires produce measurable the focus size on each of the films and determine the dependence of the effective focus size on the effective thickness of the radiation absorber. FIG. 1