DE3345865A1 - Device for moving a radiation source out and in - Google Patents

Abstract

Device for moving a radiation source out and in from or into a shielded position inside a radiation shield which can be closed on all sides. The device consists of two half shells, which can be pivoted about axes and whose mutual delimiting surfaces overlap one another, the radiation source being mounted at the front end of a push rod provided with driving means, and each of the half shells being mounted capable of pivoting about an axis perpendicular to the push rod. When the shield is closed, each of the half shells engages via a projection with a control element located on the front part of the push rod, so that when the push rod is displaced the shielding half shells pivot outwards about their axes, the shield opens, and the path is released for moving out the radiation source into the irradiation position. In this case, the radiation source can be moved by means of the push rod into the irradiation position, and the operation proceeds inversely when the radiation source is moved into the shielded position, the shielding half shells being moved by the control element and a collar of the source carrier into the closed position and fixed there.

Description

PROF. DR. DR. J. REITSTÖTTER * DR. WERNER KINZEBACH DR. ING. WOLFRAM BUNTE (» _8β -ιβ7β)

REITSTÖTTER, KINZEBACH & PARTNER PATENTANWÄLTE

POST BOX 78O. D-SOOO MUNICH 43 APPROVED REPRESENTATIVES AT

EUROPEAN PATENT OFFICE EUROPEAN PATENT ATTORNEYS

TELEPHONE: (Ο89) 2 71 65 83

CABi-ES: PATMONDIAL MUNICH TELEX: 0521S208 ISAR D TELEKOP: (O89) 271 6Ο63 (SIZE II + III) BAUERSTRASSE 22, D-8OOO MUNICH

Munich, December 16, 1983

OUR FILE: M / 24 266 OUR REF:

REFERENCE: RE

AUSTRIAN RESEARCH CENTER

SEIBERSDORF Ges.mbH
Lenaugasse 10, A-1082 Vienna

Device for extending and retracting
a radiation source

POSTAL ADDRESS; D-8OOO MUNICH 43. POST BOX 78Ο

W VW * ti. W *

The invention relates to a device by means of which a radionuclide radiation source from a shielded position can be brought to an irradiation position and back again.

Such devices are used, for example, in various isotope measuring devices, such as backscatter measuring devices, radiography devices, Radiometers, etc. used. In such devices, the radionuclide radiation source must be switched off when not in use as well as with certain operating modes of the device (e.g. blank value determination) be kept in a shielded position, whereby the type and structure of the shield must be guaranteed, so that only the amount of radiation to the outside that is permissible according to the radiation protection regulations or the maximum permissible measurement technology penetrates. On the other hand, it is often necessary, e.g. for reasons of the optimal radiation geometry, to have the radionuclide source in to bring a certain irradiation position. For safety reasons When such devices are switched off or if they fail, it must be ensured that the radiation source enters the shielded position is moved or held there. Likewise, a display is required that indicates whether the radiation source is in the shielded position, or whether the Shield is closed. In addition, the radiation source must be secured against unauthorized removal from the device.

Various shutter mechanisms are usually used to close the beam path, in which either Absorber can be pushed into the beam path or rotated into the beam path via eccentric bearings (DE-OS- 2 520 179, DE-OS-2 431 115, DE-OS-2 313 010). These shutters have the disadvantage that a minimum distance is required from the required absorber thickness between source and measuring device results, which often results in an unfavorable arrangement between radiation source detector and Material to be measured is given because the usable radiation of the radiation source is cut by the long beam path. To this avoidance is in many cases after opening the radiation

through the shutter the radiation source by means of mechanical devices such as Bowden cables, pistons etc. moved from the shielded position to the measurement or irradiation position. These two required sequences of movements must be coordinated with one another in time and generally require two independent drive devices. This requires cumbersome and complex constructions.

Based on the above-mentioned prior art, it is the object of the present invention to provide a device according to the preamble of the main claim in such a way that the simplest possible and therefore reliable operation is guaranteed is.

This object is achieved in that the source is attached to the front end of a push rod, in particular operated by compressed air is, the shield of the source consists of two half-shells, the front end faces of which overlap one another. Here, each of these half-shells is mounted pivotably about a joint perpendicular to the rod. There is also each of these half-shells via an extension in engagement with an in particular annular groove attached to the push rod, so that when the push rod is moved, the shielding half-shells pivot around the joints, the shielding opens and the The way to extend the source into the irradiation position is released. This makes it possible with a single Actuating device to perform both movements in the correct chronological order. The automatic return is preferably carried out by a return spring, which is either directly on the push rod or on the single-acting Acts compressed air cylinder.

The display of whether the radiation source is in the shielded Position is, which at the same time ensures that the shield is closed on all sides, preferably takes place in that a fluorescent surface is connected to the push rod and that a light guide through the shielding

container is mounted facing the position at which the fluorescent surface when the push rod is retracted is located.

In the following, preferred embodiments of the "invention are described in more detail using the example of a device according to the invention built into a ρ backscatter measuring probe for extending and retracting the radiation source."

In Fig. IA the entire / 7-Ruckstrumeßsonde in the form of a longitudinal section along the line I ¹ - 1 "according to Fig. IB, -in Fig. IB the bottom view of the probe, with the radiation source extended,

in Fig. 2A the beam source and its shield is in the shielded position, in

Fig. 2B shown in the extended position. Only the most essential components of the device are shown here. '

In Fig. IA is in the left side of the sectional view Radiation source in the shielded position, shown on the right in the measuring position. The source of rays (1) is located at the top of a push rod (3) actuated by a single acting 'compressed air cylinder (5). the Detectors (2) (six Geiger-Müller counter tubes) are circular attached to the source (1). The two half-shells of the shield (6) are when the Pireßluftkolbens is extended rotated by the push rod (3) with the groove (4) and with the help of the bolts (7) around the axes (8) so that the half-shells (6) open as shown in Fig. 2B, whereby the path for advancing the radiation source is released and the Radiation source is advanced into the measuring position. After switching off the compressed air, the radiation source (I) - with the push rod (3) pulled into half-shells (6) by the return spring of the compressed air cylinder (5), which is caused by the pressure of the collar (9) close against the bolts (7) and absorb the / O radiation emerging from the radiation source.

COPY

The position of the radiation source can be determined by the glass rod (11), which acts as a light guide, and on the one with fluorescent paint coated disc (13) is directed to be determined. Only if the radiation source is in the shielded. position the fluorescent color can be seen through the glass rod (11) be seen. The glass rod (11) must be fastened in the holder (12) so that the light does not pass through the holder is absorbed. The holder (12) is inserted into the cover (20) of the measuring probe.

To enable easy installation of the device in the measuring head, After loosening the screw ring (23), the inner part of the measuring probe, the one from the counter tube holder (24), the guide (22), the spacers (25) and the cover (20) are pulled out of the housing (21). To the radiation source (1), which is permanently connected to the push rod (3), to be able to remove it from the device, it is necessary to remove the Loosen the locking screw (2 7) and remove the source guide (26) to unscrew. Only then can the radiation source (1), including the push rod (3), after loosening the screw connection (28) removed from the measuring probe. To prevent unauthorized removal of the radiation source (1) from the measuring probe (30) inseparably inserted, the tongues (31) of which engage in a groove (32) in the housing (21) in the locked state.

In order to avoid high-energy bremsstrahlung, a plastic ring (40) is permanently inserted into the probe housing (21). The electronic circuit cards (41), which carry the necessary electronic part for pulse shaping, are on the guide part (22 attached. The piston of the compressed air cylinder (5) is connected to the push rod (3) by an elastic coupling (42), to compensate for manufacturing tolerances.

GOPY

Claims (5)

Pat entansprüche .j Device for extending and retracting a radiation source from or into a shielded position within a radiation shield that can be closed on all sides, consisting of two half-shells pivotable about axes, the mutual delimitation surfaces of which overlap, into or from an irradiation position
characterized, that the radiation source (1) at the front end with a Drive means provided push rod (3) is attached and ·.-.- that the half-shells (6) about an axis (8) perpendicular to the The push rod (3) is pivotably mounted, and that when the shield is closed, each of the half-shells (6) is in engagement via an extension (7) with a control member (4) located on the front part of the push rod (3), so that when the push rod (3) is moved, the shielding half-shells (6) swivel out about their axes (8), the shielding opened, and the path for extending the radiation source (1) into the irradiation position-is released, and that the radiation source (1) can be moved into the irradiation position by means of the push rod (3), and that when the radiation source is moved into the shielded position, the process is reversed, with the shielding half-shells (6) moved into the closed position by the control element (4) and a collar (9) of the source carrier and be fixed there. 2. Device according to claim 1
characterized, that with the push rod (3) a fluorescent surface (13) is connected and that a light guide (11) is mounted through the shielding container directed to that position in which the fluorescent Surface (13) in the retracted state of the push rod so that the light guide (11) shows whether the radiation source (1) is in the shielded position . 3. Device according to one of claims 1 or 2, characterized in that that the return of the radiation source (1) in the shielded position by one on the push rod (3) or on whose drive means acting return spring is effected. 4. Device according to one of the preceding claims, characterized in that that the drive means for the push rod (3) as a compressed air drive (5) are formed. 5. Device according to one of the preceding claims characterized, that the extension (7) are designed as a sliding bolt and the control member (4) as a groove, preferably as an annular groove.