US1944062A - X-ray apparatus for crystallographic examination and like purposes - Google Patents

Description

Jan. 16, 1934. A BQ WER 1,944,062

X-RAY APPARATUS FOR CRYS-TALLOGRAPHIC EXAMINATION AND LIKE PURPOSES Filed Sepfi. 4, 1928 in re n foA Patented Jan. 16, 1934 STATES PATENT OFFICE- X RAY APPARATUS F 0 R CRYSTALLO- GRAPHIC EXAMINATION AND LIKE PUR- POSES Application September 4,1928, Serial No. 303,934, and in the Netherlands February 28, 1928 5 Claims.

The invention relates to a device for examining substances with the aid of X-rays and to an X- ray tube suitable for use in such a device.

For the examination of substances, for example as to the structure of the crystals, use is often made of X-rays. When crystalline substances are struck by X-rays of a definite wave-length, these rays are reflected in a manner which depends on the structure of the crystals. These reflected rays may be intercepted by a photographically sensitive plate and the image produced thereon can be developed. From this image sufficient information can be obtained about the structure of the crystals of the substance to be examined. The installations used for this examination, are by their nature very complicated. They comprise one or more X-ray tubes and one or more apparatuses for taking photographs, the whole installation being enclosed in a metal case having walls made of a material, which does not transmit X-rays, for example of lead in order to prevent X-rays from emerging from the device. Outside the said case are provided as a rule, a transformer for supplying the required high tension and a cooling device designed to dissipate the heat developed during operation. In addition, a pumping installation is provided which serves to maintain a sufiiciently high vacuum in the tube or tubes. With such an installation the photographic-apparatuses are during operation out of reach. In order to be able to operate them, the case has to be opened, so that with the above described installations there is every danger that conductors having a high tension are touched.

The invention has for its object a simple, easily portable device for examining substances with the aid of X-rays, with which any risk that parts being under a high tension are touched, is excluded while the apparatuses for taking the photographs are continuously within reach, The device according to the invention perfectly prevents undesired X-rays from emerging therefrom while it can function without the use of a pumping installation.

The device according to the invention for ex-- amining substances with the aid of X-rays is characterized by an X-ray tube mounted inside a metallic envelope which during the use of the device may have ground potential. The outer wall of the said X-ray tube has a metallic portion which is insulated from thetwo electrodes and encloses the anticathode mirror while it is mechanically and electrically connected to the metallic envelope of the device, said envelope enclosing also a transformer, destined to supply the required high tension for the tube.

The device may be so constructed that one or more apparatuses for making X-ray-exposures are or may be secured to the metallic envelope preferably so as to be movable.

In addition, the device may comprise an electric motor with a ventilator which serve to facilitate the dissipation of heat developed during operation in the anticathode.

The X-ray tube suitable for use in a device according to the invention has an outer wall having a portion which is insulated from the two electrodes and which encloses the anti-cathode mirror, said portion being provided with two or more windows destined to transmit the X-rays.

The invention will be more clearly understood by referring to the accompanying drawing which represents a vertical section of the device according to the invention.

In the drawing, the outer wall of an X-ray tube 1 has a metallic portion 2 which is insulated from the two electrodes 25 and 26 and which is able to absorb the X-rays emanating'from the anticathode. Said portion is provided with one or more windows 3 made of a material adapted to transmit X-rays. The glass portions 4 and 5 of the X-ray tube are surrounded by a metallic envelope, consisting of parts 6 and 7 whose edges 8 and 9 are joined to the metallic portion 2 of the X-ray tube so that this portion is a continuation of the metallic outer wall of the device. In order to facilitate a rigid mounting, a mechanical connection of the wall of the tube with the metallic envelopes 6 and? may be established, for example, by means of screw threads. Due to this construction any risk of coming into contact with parts which during operation have a high tension, is eliminated while it is possible to mount the apparatuses for taking X-ray-photographs outside the device though in the immediate vicinity of the tube. Two of the said photographic apparatuses are denoted in the drawing by 10 and 11. They may be cameras according to the system Debije and Scherrer or Bohlin or the secondary winding of the transformer.

other suitable apparatuses. Preferably, they are movably secured to the outer wall of the device. With-the mode of fixation as shown in the drawing, the cameras after being slightly lifted, may be tipped over to the outside. In addition to the X-ray tube, the device comprises a transformer 12 which is mounted at the bottom of and also inside the metallic envelope and which by its weight prevents the device from being turned over. This transformer which serves to supply the high tension required for operation should preferably be entirely surrounded by oil. At the upper side, the space in which the transformer is located is closed by a plate 13 of insulating material. With the aid of a set of contact pins 14, the primary winding of the transformer may be connected via a flexible cord 15 to a source of alternating current. The secondary poles of the transformer are connected to contacts 16 and 1.7. To the contact 17, which is a double-pole contact, may be connected the filament whereas the contact 16 may be connected, by means of an exterior cable 18, to the anticathode. The supplyconductor 19 of the latter has a large diameter in order to ensure a satisfactory dissipation of heat. The cable 18 is surrounded by a metallic envelope which is electrically connected to the outer wall of the device. By means of a clamp 20 a ground-connection may be secured to the said outer wall so that this wall and also the metallic envelope of the cable 18 are on ground-pm tential and consequently can be touched without the slightest danger. As a further safeguard, the

means for securing the cable to the device may be such as set forth in applicants copending U. S. application No. 303,933 filed September 4,

1928 so that the current for feeding the transformer cannot flow until both ends of the cable are connected or secured to the device. In order to facilitate the dissipation of heat developed dur- 'ing operation in theanticathode, an electric motor 21 with a ventilator is provided at the top of the device. Also other cooling means may be used in a device according to the invention. Thus, for example, the protruding part of the supply conductor 19 may be located in oil which is cooled by water. For this purpose the tube 1 may be so mounted in the device that the anticathode points downward so that the currentsupply conductor 19 is located in the same oilchamber as the transformer.

As the principal parts of the device are enclosed within a single envelope of limited dimensions, the whole device is easily portable and can,

for example be arranged on a table in a simple manner. With the aid of handles the device can be lifted, one of the said handles 22 being indicated in dotted lines.

As appears from the drawing, the construction by another, which is a great advantage if the use of different X-ray frequencies is desired. By opening a shutter 23 provided in the wall, one is enabled to reach the contact 1'7 and to break the connection of the incandescent cathode to (If with the shutter 23 is connected a contact device 2% which ensures that the primary circuit of the transformer remains interrupted as long as the v shutter is open, the contacts 16 and 17 cannot be touched while being under tension). Subsequently, the cable may be disconnected at the top and so may also the electrical connection of the ventilator motor, if any, whereupon the upper part 6 of the metallic envelope can be removed. Now the X-ray tube can be removed from the device and be replaced by another. In the reverse sequence the device can be put together again whereupon it is again ready for use.

The tubes for a device according to the invention may be provided with windows for the transmission of X-rays, which are not porous and from which during operation substantially no gases are liberated; they may, for example, be made of Lindeman-glass. Owing to this, it is not necessary to keep the device during its operation connected up to a pumping installation.

What I claim is:

1. An apparatus for the examination of substances with the aid of X-rays comprising an X-ray tube, the wall of which has a metallic portion, secured to insulating portions and insulated from the electrodes of the tube, said metallic portion surrounding the path of the discharge and being mechanically and electrically connected with a metallic envelope, which is adapted to be grounded during the operation and surrounds an insulating portion of the tube, said metallic envelope enclosing a transformer for high tension supply electrically connected to the electrodes of the tube, and having externally secured to it at least one device for taking X-ray photographs.

2. An X-ray apparatus provided with an X-ray tube having two electrodes, a cathode and an anode and a cylindrically shaped outer wall comprising two insulating parts each carrying an electrode and constituting an insulating connection between said electrodes and a metallic portion of the wall which surrounds the path of the said metallic wall portion, enclosing in spaced re-' lation the insulating part of the tube that carries the anode and supporting an electric fanmotor.

3. An X-ray apparatus comprising an X-ray tube, having electrodes and a wall having a metallic portion, said metallic portion being secured to insulating parts and being insulated from the electrodes of the tube, a support for said tube and a transformer for high tension supply electrically connected to the electrodes of the tube, said support, adapted to be grounded during the operation, consisting of a hollow metallic pedestal enclosing said transformer and engaging the said metallic portion of the tube.

4. An X-ray apparatus adapted for the examination of substances, comprising an X-ray tube having at least two electrodes, a metallic is adapted to be grounded during the operation, each of these metallic envelope parts surrounding one of the insulating parts of the tube wall, one of said metallic parts enclosing a transformer for high tension supply electrically connected to the electrodes of the tube and having externally secured to it at least one device for taking X-ray photographs.

ALBERT BOUWERS.

Images