EP3020049A1

EP3020049A1 - Beam shutter, in particular for x-rays

Info

Publication number: EP3020049A1
Application number: EP14736849.2A
Authority: EP
Inventors: Norbert Haunschild
Original assignee: Smiths Heimann GmbH
Current assignee: Smiths Heimann GmbH
Priority date: 2013-07-10
Filing date: 2014-07-09
Publication date: 2016-05-18
Anticipated expiration: 2034-07-09
Also published as: WO2015004185A1; US10153060B2; CN105378853A; CN105378853B; EP3020049B1; US20160211044A1; DE102013107310A1

Abstract

The invention relates to a device (1) for closing and opening a beam path (3) of electromagnetic and/or ionising radiation, comprising: at least one part (5), which is arranged permanently in the beam path (3), of a shutter body (9), which can be rotated about a longitudinal axis (7) arranged substantially transversely to the beam path (3) and which has a material that is opaque to the radiation and blocks the beam path (3) when the shutter body (9) is in a closed rotary position (B) and which defines a passage (11) that is transparent to radiation when in an open rotary position (A); and a drive means (13), which is coupled to the shutter body (9) in order to rotate same about the longitudinal axis (7) between the rotary positions (A, B), wherein the drive means (13) is an electromagnetic drive and is designed to move the shutter body (9) between the rotary positions (A, B), wherein at least one of the rotary positions (A, B) corresponds to a stable position of the magnetic drive that holds the magnetic drive without using current.

Description

Radiation occlusion, especially for X-rays

FIELD OF THE INVENTION The invention generally relates to a device for closing or

Sharing a beam path for electromagnetic or ionizing radiation. The invention relates in particular to a closure device with a rotatable

Closure body arranged with a substantially transverse to the beam path

Axis of rotation. Background of the invention

DE 34 30 348 A shows an X-ray shutter to terminate the

X-ray exposure of an object, in the event that the capacity of

Power supply cables to an X-ray tube even after a programmed

Exposure time nor supply power or power to the X-ray tube. This is one

Exposure control connected to a first solenoid which, prior to or upon excitation of the x-ray tube, pulls a radiopaque lead, tungsten or uranium gate against the pulling force of a spring to an open position in which the shutter is held by a retainer of a second relaxed solenoid. In the open position, a radiation window in the shutter allows X-rays to pass through.

After a controller initiates X-ray generation, and as soon as a sensor detects a preset exposure threshold, the controller energizes the unstressed solenoid, which removes the retainer from the closure. The mass of the shutter and the force of the spring are selected so that the shutter can be moved from the open position to a closed position in about 1/5000 of a second to quickly break the X-ray radiation.

A problem with the known closure devices, in which the closure of the beam path by means of a slider, which in a direction transverse to

Beam path is introduced, is that responsible for the required rapid actuation of the shutter spring can fatigue or break over time. Furthermore, the arrangement of spring, slide, retaining pawl complex and claimed due to the Linear movement of the slide relatively much installation space. To the size of the

Slider and thus to be able to keep its mass small, a close arrangement at the radiation source is required, because there to be closed cross-sectional area of the

Radiation is small. Finally, in the spring-actuated linear movement of the slider, a damping means for avoiding rebounding of the slide at the end position is necessary, ultimately the dimensioning of spring, slide and

Damping element will always represent a compromise solution.

US 5 107 530 A shows a rotary closure which is locked between a first position, in which an X-ray path is blocked, and a second position, in which

X-ray path is opened, according to the preamble of claim 1. At the known rotary closure, a closure position indicator with optical sensors is provided in order to detect a reliable rotation of the rotary closure by means of a magnetic drive in one of the first or second position. The known rotary shutter and the control of the position of the shutter are complex.

Summary of the invention

It is a possible object of the invention to propose a closure device and a method for releasing or closing the beam path of electromagnetic and / or ionizing radiation, which has a simple structure.

This object is achieved at least in part with the features of the independent claims. Further features and details of the invention will become apparent from the dependent claims, the description and the drawings.

The core idea of the invention is a rotatable closure body instead of a linearly to be moved in the beam path slider with a magnetic drive as a drive means for the rotation of the closure body between a closing rotational position in which the beam path is closed, and an open-rotational position, in the of the

Beam path for the radiation is released to use, "released" here means in principle that the closure body in the open-rotational position for the

Application coming radiation in this position transparent so at least for a certain frequency or wavelength range of the radiation is permeable, ie it can In principle, further material of the closure body are in the beam path, which is then transparent or permeable to the radiation or at least a part thereof.

According to a first aspect of the invention, a device for closing or releasing a beam path of electromagnetic and / or ionizing radiation comprises: a closure body permanently arranged in the beam path and rotatable about a longitudinal axis substantially transverse to the beam path and having a material which is impervious to the radiation closes the beam path in a closed rotational position, and transparent to the radiation in an open rotational position

Passage; that is, as compared with known slider or shutter assemblies in which one (or more) shutter member (s) is translationally moved from one (or different) direction (s) into the beam path, this is

Closure element of the invention permanently in the beam path, wherein there are two rotational positions, namely the closed rotational position in which it closes the beam path or seals against the radiation or blocks the radiation, and the open-rotational position in which the radiation or at least ^' a part of it essentially unimpeded

Closing body can happen, has. Next, the closure device

Drive means which is coupled to the closure body to rotate about the longitudinal axis between the two rotational positions. As drive means, an electric magnetic drive is provided which is adapted to move the closure body between the two rotational positions. At least one of the two rotational positions corresponds to a stable position of the magnetic drive, which can keep the magnetic drive de-energized (beibe-).

According to a second aspect of the invention, a method for releasing and closing a beam path for electromagnetic and / or ionizing radiation comprises the following steps: rotating a part of a closure body which is permanently arranged in the beam path and rotatable about a longitudinal axis arranged essentially transversely to the beam path for the radiation dense material in an open-rotational position, so that a formed in the closure body for the radiation transparent passage is made to coincide with the beam path. Rotating the shutter body arranged in the beam path in a closed rotational position, so that the beam path is closed by the radiation-tight material of the closure body.

Execution of the respective rotational movements of the closure body between the

Rotary positions by means of an electric magnetic drive, and energized holding at least one of the rotational positions of the magnetic drive by means of one of these

Rotary position associated permanent magnet.

Particularly advantageous in the inventive device or the

The inventive method is that when combined from drehbetätigtem

Closure body and electric magnetic drive particularly short switching times between the two closure conditions can be achieved.

Features and details associated with the invention

Closing device for closing or releasing a beam path

Electromagnetic and / or ionizing radiation will be described below, of course, apply in connection with the above

According to the invention and in each case vice versa, so that with respect to the disclosure of the individual features of the invention here is mutually referenced or can be

In a first embodiment of the closure device, the drive means may be a monostable electric magnetic drive, i.e., have a stable position. The closure device may be configured such that a predetermined end rotational position of the closure body corresponds to the stable position of the magnetic drive.

For example, the magnetic drive by means of a built-in for this purpose

Permanent magnets, the predetermined end position without current, i. without supply of electric current, keep (beibe-).

When the predetermined rotational position is the closing rotational position, the

Execution particularly advantageous with regard to radiation safety, since the beam path is only actively open, ie must be kept open. That is, in the event of a fault can be ensured solely by interrupting the power supply to the solenoid drive that the closure device occupies the Verschließ-rotational position and thus the beam path blocked. It is particularly advantageous that the actual closing operation then takes place without current, ie, without supply of external power.

In a second alternative embodiment of the closure device, the

Drive means are a bistable electric magnetic drive, that is, have two stable positions. The closure device may be configured so that each of the two

(Function) rotational positions of the closure body corresponds in each case one of two stable positions of the magnetic drive, which can keep the magnetic drive de-energized (beibe-).

In other words, in the bistable embodiment, the magnetic drive can in each case hold one of two predetermined end positions, for example in each case by means of a permanent magnet installed therefor, de-energized. Between the structurally stable

End positions, there may be an unstable equilibrium point, the drive will automatically move from the equilibrium point to the nearest stable end position with appropriate control or deflection.

It is particularly advantageous here that this embodiment of the closure device has no appreciable power requirement, since the electric magnetic drive only has to be always supplied with electrical energy for short rotation of the closure means. Due to the only short working phases for the electric magnetic drive, this can be operated in the overload area in order to achieve maximum acceleration. It has been found that the time between the phases of movement or working is sufficient for a cooling of the magnetic drive, that is, the drive is in the short-term

Overload in the working phase warm, but remains below the specified

Upper temperature limit. Therefore, there are substantially no particular restrictions on the heat dissipation to be ensured with respect to the installation site.

The drive means may be an electric rotary magnetic drive, but also a

Be linear magnetic drive; if a linear solenoid drive is used, the

Linear motion, for example via a lever mechanism in the required

Rotary movement to the required movement, ie rotation, the closure body to be implemented. The electric magnet drives which are preferred for the closure device can be based essentially on the following fundamental design principle. A wound example of copper wire coil forms together with an open

Iron core an electric magnet, with the mechanical work in the form of movement or a holding force can be generated when electric current flows through the coil. As a linear drive of the magnetic drive is designed so that an anchor performs a rectilinear lifting movement in current flow. Depending on the design, the

Press the lifting movement of the armature when pulling on the current, pulling it or pulling it from one side

Mittellage also both. As a rotary drive of the magnetic drive is configured so that the armature when current flows through the coil generates a purely rotational movement, similar to an electric motor on the drive shaft. In contrast to the electric motor, the armature of the rotary magnet drive can not rotate continuously, but only over a predetermined angle of rotation; the rotational movement can take place in a clockwise, counterclockwise or even in both directions, then starting from a central position. The closure body can, for example, in a device for forming the

Be installed radiation. Such a forming device may be a collimator. The closure body can also be used as a closure directly on the housing of a device for

Generation of the radiation can be arranged. Such a radiation-generating device may be, for example, an X-ray tube for generating X-rays. The closure body may be shaped so that in the open-rotational position to

Beam passage directed inner surfaces of the passage are formed so or so that they are substantially inner with the beam path bounding housing surfaces, i. Housing internal surfaces, aligned or the clear cross-section of the beam path is not limited. Alternatively, also with the passage, the desired clear cross section of the beam path can be defined, i. facing the beam path

Inner surfaces or for the case that the closure body of different materials, a portion with dense for the radiation material and a portion with transparent for at least a portion of the radiation material, determine the defined boundary surfaces the effective cross section of the beam path. In certain embodiments, the closure body, at least in the region or part which is permanently in the beam path, substantially or approximately have the shape of a half-cylinder or cylinder portion.

In certain embodiments, the closure body may have substantially or approximately the shape of a solid cylinder at least in the area or part which is located in the beam path, wherein the passage may be in the closure body as a slot or window extending transversely to the longitudinal axis.

The passage may, in a particularly simple case, be defined by the absence of any material in the closure body, i.e., the passage in the closure body

Closure body can be made free of material.

Alternatively, the passage in the closure body may be defined or formed by a correspondingly shaped material integrated into the closure body, which is transparent to the radiation. In this variant, the closure body can be inserted into a device defining the beam path so that the shutter additionally hermetically seals the beam path.

The above embodiment can be advantageously developed by the passage in the closure body by a correspondingly shaped and in the

Closing body integrated filter material is defined or formed, wherein the filter material is selected so that the continuous X-rays are selectively filtered.

For example, the filter material can be chosen to harden the x-ray radiation in a defined manner. "Cured" means that low energy x-ray quanta are absorbed by the filter material and those with high energy are largely transmitted, in other words the softer, ie longer and less penetratable X-rays are filtered out, eg aluminum, copper or similar material can be used as filter material Furthermore, it is also possible to filter out certain hard X-rays, ie short-wave and therefore high-energy parts of the X-ray spectrum of the X-ray radiation, as filter material For this example, a material with a higher atomic number, such as zirconium,

Molybdenum, rhodium or the like.

The closure body and / or the drive means may be mechanically configured so that only a movement in a predetermined range is possible. For example, the two (functional) rotational positions (open / close rotational position) associated end stops can be provided on the closure body and / or the drive means, so that the closure body and the drive means is mechanically movable only in an area defined by the end stops range. As a result, the respective rotational position of the closure body can be ensured particularly precisely. In addition, elastic end stops can be provided, which reduce the kinetic energy of the

Record the closure body when taking one of the (functional) rotational positions.

The invention is particularly suitable as a closure device for the beam path in an X-ray inspection system.

Depending on the embodiment, the closure device may be configured as a safety device, wherein a closure position of the closure device is a monostable position into which the closure body is automatically rotated when a power supply required to hold the closure body in the unstable open position, e.g. Power supply, is interrupted. This variant is particularly suitable, for example, if as a radiation source no electric X-ray tube but a

Permanent radiator with e.g. a cobalt-60 radiation source is used. The monostable closure device can particularly easily ensure automatic closure of the radiation source in the event of a power failure.

It is also possible to configure the closure device bistable, wherein in each case the closing position and the open position of the closure device is a stable position, is held in the closure body automatically. Here is in each case for rotating the closure body of one of the two positions in the other a corresponding one

Energy supply, eg a current pulse, necessary. Brief description of the drawing figures

Further advantages, features and details of the invention will become apparent from the following description in which with reference to the drawings

Embodiments of the invention are described in detail. The features mentioned in the claims and in the description may each be essential to the invention individually or in any desired combination. Likewise, the features mentioned above and the features listed further here can be used individually or in any combination. Functionally similar or identical components or components are partially provided with the same reference numerals. The in the

DESCRIPTION OF THE EMBODIMENTS Terms "left," "right," "top," "bottom" used in the drawings refer to the drawings in a normally legible figure designation. The embodiments shown and described are not to be understood as exhaustive enumeration, but rather have exemplary character for the description of the invention. Figure 1 shows a sectional view from above of an embodiment of a

Locking device according to the invention, which is integrated in a fan-beam collimator;

Figure 2a shows a sectional view 2-2 of Figure 1, in which the closure means of

Closing device releases the beam path;

Figure 2b shows a sectional view 2-2 of Figure 1, wherein the closure means of

Closing device closes the beam path;

FIG. 3a shows a perspective view of a detail of the closure device of FIG. 1, in which the closure body is in the open rotational position; and

FIG. 3b shows a perspective view of a section of the closure device of FIG. 1, in which the closure body is in the closing rotational position.

DETAILED DESCRIPTION OF AN EMBODIMENT The invention will be described below with reference to the figures with reference to FIG

Embodiment described in detail. The detailed description serves the

Information of the skilled person and is not to be construed restrictive. In the following For description, numerous specific details are set forth. It is understood, however, that embodiments of the invention may be used without these specific details. Circuits, structures and methods known to those skilled in the art will not be discussed in detail here in order to avoid unnecessarily obscuring the understanding of the present description.

Terms "coupled" and "connected / connected" and terms derived from them are not used synonymously here. Rather, in specific embodiments, "connected" may indicate that two or more elements are in direct physical or electrical contact with each other. "Coupled" may mean that two or more elements interact or affect each other, being in direct, but also direct Unless otherwise indicated, the use of the ordinal adjectives "first," "second," "third," etc. to denote a common object merely indicates that reference is made to various examples of similar objects , and is not intended to imply that the objects so designated must occur in a certain temporal, spatial, hierarchical or other order.

Figure 1 shows a sectional view from above of an embodiment of a closure device 1 according to the invention, adjacent to a narrower end in a fan beam collimator 1 5 to form a fan-shaped

X-ray beam is integrated.

The fan beam collimator 1 5 of the embodiment shown here is in

Essentially of two trapezoidal congruent halves each having a small side 1 5a and a large side 1 5b. The halves form in the assembled state, a beam path 3 for in one on the small side 1 5a coupled

X-ray source (not shown) generated X-rays. The X-rays are irradiated on the small side 1 5a of the collimator 1 5 in the beam path 3 and leave this in an angle range defined by the collimator on the large side 1 5b.

It should be noted that the housing of the fan beam collimator 1 5 need not necessarily be constructed of two halves. For example, the housing can also be in one piece or formed integrally, ie, for example, be a one-piece casting, a correspondingly shaped and aligned recess, such as a matching hole for the

Has closure body.

Adjacent to the small side 1 5a, a part 5 of a closure body 9 is permanently arranged in the beam path 3. The closure member 9 is rotatably mounted about a longitudinal axis 7 extending substantially transversely to the beam path 3 at its longitudinal ends 9a, 9b by means of known storage means 16a, 16b in the collimator 15.

The closure body 9 itself, that is to say the part which serves to close the beam path 3, consists of a material which is dense for X-ray radiation, such as, for example, lead, tungsten, uranium or tantalum; Instead of tantalum, it is also possible to use niobium or zirconium or an alloy of 80% to 90% tantalum, niobium and zirconium. Alternatively, gold, ceramics, sintered materials of tungsten with copper, nickel and / or iron or the like, to name a few further examples are also suitable.

The material of the housing parts or the housing of the collimator 1 5 also consists of a dense for X-ray radiation material, this may also be the elements mentioned in connection with the closure body 9 or alternatively steel or brass.

The closure body 9 is shaped such that by means of the closure body 9 in an open-rotational position A (Figure 2a, 3a) for the x-ray radiation transparent

Passage 1 1 is defined. FIG. 2a shows a sectional view 2-2 of FIG. 1, in which the closure means of the closure device releases the beam path. FIG. 3a shows a perspective view of a detail of the closure device of FIG. 1, in which the closure body is in the open rotational position A. FIG.

More precisely has the part of the closure body 9, which from the for

X-ray dense material is essentially the shape of a solid cylinder. The passage 1 1 extends with respect to the axis of rotation corresponding longitudinal axis 7 radially or centrally through the closure body 9. As partially with reference to the figures 3a, 3b recognizable, the passage 1 1 in the main direction of the beam path 3 has a rectangular cross-section. In the open-rotational position A directed to the beam 3 inner surfaces 1 7a, 1 7b, 1 7c, 1 7d of the passage 1 1 aligned so that they with the beam path 3 bounding inner Cehäuseflächen 1 9a, 1 9b, 1 9c, 19d of Fan beam collimator 1 5 alignment (areas 1 7c, 1 7d) and define the clear cross-section of the beam path 3 (areas 1 7a, 1 7b).

The closure body 9 is further shaped so that in a closed-rotational position B (Figure 2b, 3b) of the closure body 9, the entire clear cross section of the beam path 3 is blocked by means of the dense X-ray material. FIG. 2b shows a sectional view 2-2 of FIG. 1, in which the closure body 9 completely closes the beam path. FIG. 3b shows a perspective view of a detail of the closure device of FIG. 1, in which the closure body is in the closed position B of rotation.

A drive means 1 3 is coupled to the closure body 9 to rotate about the longitudinal axis 7 between the rotational positions A, B via a shaft 1 0. The

Drive means 1 3 is in the illustrated embodiment, an electrical bistable

Magnetic drive with two stable end positions, the magnetic drive in each case in the de-energized state, i. without supply of electric energy in the form of electric current, stably maintained. For example, at least two for this purpose in the magnetic drive

Permanent magnets may be arranged, by means of which the magnetic drive can be kept de-energized in each case in a predetermined position, each of the two rotational positions A, B of the closure body 9 is associated with one of these two stable positions of the magnetic drive.

In the embodiment shown, the drive means 1 3 is an electrical bistable rotary magnet. That is, the drive means 1 3 generates directly required for the actuation of the closure device 1 rotational movement. Bistable rotary magnets have fast reaction times and keep without current supply the respective predetermined stable position or end position. Since only for a short time the operation of the closure device electrical energy is needed, consuming bistable magnetic drives little energy and generate due to the short work phases only little heat loss. On the shaft 1 0, which couples the rotor 1 3a of the drive means 1 3 with the closure body 9, a rotation stop member 12 is fixed in the form of a lever. On the housing of the drive means 1 3 are the two rotational positions A, B associated end stops 21 a, 21 b (the stop 21 b is hidden in the illustration, but basically similar to the 21 a executed) so firmly arranged that the closure body 9 and the Drive means 1 3 only in the angular range defined by the two end stops 21 a and 21 b, which essentially corresponds to a 90 ° rotation of the closure body 9, can be moved. End stops 21 a, 21 b are provided with an elastic material, for example an elastomer, for example material such as rubber or a rubber-like material, ie a material which has elastic properties similar to rubber, which is the kinetic

Energy of the moving closure body 9 when taking one of the rotational positions A, B receives.

When de-energized, there is an unstable equilibrium point in the

Middle position between the two end stops 21 a and 21 b, each one of the stable operating points of the magnetic drive per direction of rotation, in which the rotor 1 3a automatically rotates, as soon as it is deflected from this center position in the respective direction correspond. The torque required for this purpose is only with this in the

Magnetic drive built-in permanent magnet generated. Since the end stops 21 a and 21 b are each arranged slightly in front of the stable end positions of the rotor 1 3a, the rotor 1 3a remains in these end positions until it is active, i. by means of power supply over the

Center position is deflected towards the other end position.

The electric magnetic drive can be controlled, for example, via a bipolar amplifier, such as a bipolar stepper motor amplifier module. Preferably, the magnetic drive is controlled in each case between the rotational positions of the closure body 9 via a current pulse, wherein the pulse length of the current corresponds to the movement time in the respective other rotational position of the closure body 9.

On the basis of the embodiment described above, a device 1 for closing or releasing the beam path 3 for electromagnetic and / or ionizing radiation, namely X-radiation, explained. The invention is not limited to the embodiment described, but rather the scope of the invention results from the following claims. The closure device 1 has at least one permanently arranged in the beam path 3 part 5 of about a substantially transverse to the beam path 3 arranged longitudinal axis 7 rotatable closure body 9, which has a dense material for the radiation, which in the closed rotational position B of

Block body 9 blocks the beam path 3, and defines a transparent in the open rotational position A for the radiation passage 1 Ί, and a drive means 1 3, which with the closure body 9 to rotate about the longitudinal axis 7 between the rotational positions A, B is coupled, wherein the drive means 1 3 an electrical

Magnetic drive is and is adapted to move the closure body 9 between the rotational positions A, B, wherein at least one of the rotational positions A, B corresponds to a stable position of the magnetic drive or is assigned, which can keep the magnetic drive de-energized.

Claims

claims

1 . Device (1) for closing and releasing a beam path (3)

Electromagnetic and / or ionizing radiation comprising at least one permanently in the beam path (3) arranged part (5) of a transversely to the beam path (3) arranged longitudinal axis (7) rotatable closure body (9) having a dense material for the radiation, which blocked in a Schliefs-rotational position (B) of the closure body (9) the beam path (3), and defines a in an open-rotational position (A) transparent to the radiation passage (1 1), and an electric magnetic drive as

Drive means (1 3), which is coupled to the closure body (9) for rotation about the longitudinal axis (7) between the rotational positions (A, B),

characterized in that the electric magnetic drive is adapted to move the closure body (9) between the rotational positions (A, B), wherein at least one of the rotational positions (A, B) corresponds to a stable position of the magnetic drive, which maintains the magnetic drive de-energized.

2. Closure device according to claim 1,

wherein the drive means is a monostable magnetic drive, which automatically returns to a stable end position in the de-energized state, wherein one of the rotational positions (A, B) is associated with the stable position and the other an unstable position of the magnetic drive.

3. Closure device (1) according to claim 1,

wherein the drive means (1 3) is a bistable magnetic drive and each of the two rotational positions (A, B) corresponds to one of two stable positions of the magnetic drive, which maintains the magnetic drive de-energized.

4. Closure device (1) according to claim 1, 2 or 3,

wherein the drive means (1 3) is a rotary magnetic drive or a linear magnetic drive.

5. Closure device (1) according to one of claims 1 to 4,

wherein the closure body (9) in a device (1 5) for forming the Radiation, such as a collimator (1 5), or at a device for generating the

Radiation, such as an X-ray tube, is arranged.

6. Closure device (1) according to one of claims 1 to 5,

wherein in the open rotational position (A) to the beam path (3) directed inner surfaces (1 7a, 1 7b, 1 7c, 1 7d) of the passage (1 1) are formed so that the inner surfaces (1 7a, 1 7b, 1 7c, 1 7d)

- With the beam path (3) limiting housing surfaces (19 a, 19 b, 1 9 c, 19 d) are aligned, or

- Do not limit the clear cross section of the beam path (3), or

- Define the clear cross-section of the beam path (3).

7. Closure device (1) according to one of claims 1 to 6,

wherein the closure body (9) at least in the region which is permanently in the beam path (3),

- Has the shape of a half-cylinder or cylinder portion, or

- Has the shape of a solid cylinder, wherein the passage (1 1) extends substantially radially through the closure body (9), and preferably a rectangular

Cross section has.

8. Closure device (1) according to one of claims 1 to 7,

wherein on the closure body (8) or the drive means (1 3) the two

Rotary positions (A, B) associated with end stops (21 a, 21 b) are provided such that the closure body (9) or the drive means (1 3) only in one of the stops (21 a, 21 b) defined area, the in about a 90 ° rotation of the closure body (9) corresponds, is movable.

9. A method for releasing and closing a beam path (3) for

Electromagnetic and / or ionized radiation has the steps of

Turning one in the beam path (3) permanently arranged and one in the

Substantially transversely to the beam path (3) arranged longitudinal axis (7) rotatable part of a closure body (9) of a dense material for the radiation in an open rotational position (A), so that in the closure body (9) formed for the radiation transparent passage ( 1 1) is brought to coincide with the beam path (3); Rotating the closure body (1 1) arranged in the beam path (3) into a closed rotational position (B) so that the beam path (3) is closed by material of the closure body (9) which is dense for the radiation;

Execution of the respective rotational movements of the closure body (9) between the rotational positions (A, B) by means of a drive means (1 3), and currentless holding at least one of the rotational positions (A, B) of the drive means (1 3) by means of one of these rotational position (A, B) associated permanent magnet.

1 0. Röntgenprüfanlage with an X-ray source, a closure device (1) according to one of claims 1 to 8, and a control device, with the

Closure device is operatively connected and arranged to control the closure device according to the method of claim 9.