US2899556A

US2899556A - Apparatus for the treatment of substances

Info

Publication number: US2899556A
Authority: US
Priority date: 1952-10-17
Publication date: 1959-08-11
Anticipated expiration: 1976-08-11
Also published as: GB777428A; DE971610C; GB777426A; GB777427A; FR1090183A; NL109549C; CH332987A

Description

I 8 8- 1959 E. SCHOPPERET AL 2,899,556

-APPARATUS FOR THE TREATMENT OF SUBSTANCES WITH CORPUSCULAR RAYS Filed Oct. 14, 1953' 2 Sheets-Sheet 1 INVENTORS- ERWIN SCHOPPER 0nd BERTHOLD SCHUMACHER m? V (flia rh xf ATTORNEYS Aug. 11, 1959 Filed Oct. 14, 1953 (E. SCHOPPER ET AL APPARATUS FOR THE TREATMENT OF SUBSTANCES WITH CORPUSCULAR RAYS 2 Sheets-Sheet 2 v e H. 1 1 2| IIHIII F 28 S 5" 22 25 1 \2\ I 29 l/ A 1's 2e j 23 so 9 I5 27 w i i 'L .W 24 v 46 2o l6 I I 3 INVENTORS YBY ERWIN SCHOPPER and BERTHOLD SCHUMACHER ATTORNEYJ' Uit States 2,899,556 Patented Aug. 11, 1959 ice 2,899,556 APPA ATUsFoR THE TREATMENT oF STANCES WITH'CORP'USCULAR RAYS Erwin Schopper' and Berthold Schumacher, Stuttgart, Germany lt is known that electron beams and other corpuscular i'ays produced and concentrated by Well known means,

can be utilised for the heating and for the evaporation of substances. The advantages of this method, residing in the possibility of great energy concentration and of inertialess control, are however largely off-set by the "necessity either of introducing the materials to be acted upon or to be heated into a vacuum, which involves technical difficulties and reduces economy, or of providing material windows, i.e. thin foils consisting preferably 'ofalu'minium which are placed in a vacuum-tight'manner upon a through aperture in the wall of the beam gen- "erating chamber, and through which the corpuscular beam must then be conducted, which involves considerable consists of a series of chambers with increasing air pressures, which are arranged in series in the direction of the beam and possesses fine aligned apertures in the partition walls so that only a fraction of the total -.'p'ressure dilferenc'e will be effective to cause entry of air through each aperture, while the'corpuscular beam can be conducted through the apertures and thus, stage- -by'-sta'ge, from the vacuum chamber into chambers of progressively higher gas pressure and finally into the "working space, which may be the free atmosphere or a chamber with essentially atmospheric pressure. Electron microscopy is, however, concerned only with very small concentrations of energy.

The presentinvention relates to an apparatus for the treatment of substances adapted to be controlled without inertia 'and'localised within narrowly confined spatial limits with the particularly characteristic feature that an electric corpuscular beam produced and concentrated in a vacuum by well known means is conducted outof the vacuum through the medium of a :dynamic pressurestage stretch without the employment of material windows, into a space containing gas at a pressure comparable to atmospheric pressure and is caused to impinge 'upon'the sharply confined part of space in which the'treatment is desired to take place.

For many technical and scientific purposes the appara'tus of the invention is of great importance for obtaining a treatment requiring high energy transforma- "tiofis'controllable in an inertialess manner, 'confinedwithin narrow spatial limits by the use of a corpuscular beam co ducted out of the generating chamber through a dynamic pressure-stage stretch.

Theinvention mak'es'it possible to'generate locally confined and controllable without inertia, 'very high temperatures and 'thiseffect can be utilised for cutting by burning substances moved perpendicularly to the cor- 'puscular beam or for the thermic blasting of holes in *imetallic 'or non-metallic stationary objects. 'Even finespatial shapes 'may be burned out under suitable movement of thebeam apparatus or of the object, by the gradual removal of surface portions. 'In the production of fine spinning passages and spinning nozzles, the invention permits very fine, smooth bores with walls of high quality to be obtained.

It is further proposed to employ the high energy of a concentrated electron or ion beam conducted out of the vacuum according to the invention and converted into heat by impact upon matter, for the heating, melting,

evaporation or sublimationof high-melting substances, advantageouslyund'er a protective gas, without heat supply by mate-rial heat conduction'or by heat radiation being necessary. The possibility of inertialess control permits a dosed energy conversion and thereby the evaporation of predetermined quantities. For example, this method is of great importance for the-melting and evaporation of many oxides.

The invention also makes it possible for confined volume portions of gases to be heated very rapidly to very 'high temperatures which, for example, may be utilised for the generationofthermic pressure pulses and, with a suitable beam frequency, for the generation of intensive .sound oscillations in gases. The volume heating may also be utilised for the separation of gaseous mixtures by thermic diffusion; for example'an isotope separation may be effected-in thismanner.

With the help of a corpuscular beam conducted out of the vacuum according to the invention chemical reactions 'may also be initiated or maintained between gases, solids, or liquids individually or in any other combination, including for example, reactions between an irradiate solid body and the surrounding gas, or chemical reactions between any of the said substances and the particles of an ion beam. Thus the method is suitable for hydrogenation'by means of a proton beam or for oxidation by means of an oxygen-ion beam.

Since the duration, the intensity, the direction and the corpuscular beam can be very well controlled and the necessity of working under vacuum is eliminated, the invention also allows living tissue to be irradiated for the production of biological or therapeutic eifects.

It is of scientific interest that the invention makes it possible with the help of a corpuscular beam apparatus equipped with a pressure-stage stretch, to excite any suitable substances, including even substances which become unstable ina vacuum, for the emission of X-ray radiation with great intensity in anormal atmosphere.

Thus the, invention makes it possible for the first time to carryout the X-ray spectrographic analysis of solutions and of liquid substances.

Also, the invention has been found useful and may serve for temperature and density measurement in hot flames, e.g. in the propulsion jet of a rocket or for the supervision of chemical reactions. In the latter case one may, for example, measure the partial pressures of individual'reaction components by drawing conclusions from thedispersion 'ofa corpuscular beam, particularly a beam (10 Hg), "aiworking chamber containing the material tofbe treated, the gas pressure in this working chamber being more than 1 Torr, and at least one pressure-stage chamber interposed between the generating chamber and the -'i'yorking chamber, in which the gas pressure has a-value-between the pressures in said two chambers, the partition walls between the individual chambers being provided, at the passage points of the beam, with fine orifices making possible the unimpeded passage of the corpuscular beam with such a distance, within the order of magnitude of the orifice diameters, that the formation of density maxima anddensity minima in the inflowing jet of gas is utilized and the orifice nearest the direction of the inflowing jet of gas comes to lie in a density minimum.

In order to further explain the invention one embodiment of the apparatus and its manner of operation will now be described by way of example with reference to the accompanying drawings.

Fig. 1 is a somewhat diagrammatic sectional elevation showing a beam generating apparatus comprising a twostage pressure-stage stretch incorporated in the path of the. corpuscular beam and an object arranged in front of it, which object, for example, is intended to be pierced.

In Fig. 2 is a fragmentary representation, to a larger scale, of the front part of the pressure-stage stretch shown in Fig. l, which shows the relation between the dimensions of the orifice, which is an aperture at the end of a nozzle in the illustrated instance, and its distance from the exit orifice, on the one hand, and the shape of the jet of gas entering from the working chamber, on the other hand.

Fig. 3 similarly illustrates a well tried form of a fourstage pressure-stage stretch.

Referring now to the drawings, 1 indicates the preferably cylindrical vacuum chamber with a vacuum tight metal wall 2, into which chamber there projects from one of the end faces with vacuum tight seal a corpuscular ray generating source 4, which may be of any conventional design and which includes the mounting 3. For example, a concentrated powerful cathode-ray beam may be generated with a conventional telefocus cathode 4 with a Wehnelt cylinder, as described in Optik, vol. 5 (1949), page 469. This is an electron-optical device for focusing the electron beam emitted from a conventional tungsten wire cathode. Alternatively, however, cold cathodes, channel-ray or ion sources and other particle generators and accelerators with the required concentrating (focussing) means may be provided. The wall 2 of the vacuum chamber forms, in the illustrated embodiment, the anode and is grounded. The end wall, situated in the direction of the beam, of the cylindrical vacuum chamber 1, preferably has the shape of an outwardly directed cone shell and is provided at its apex 5 with a nose-like perforated projection adapted to accommodate a nozzle pin 6 provided with a capillary 17 for the passage of the corpuscular beam. The intermediate pressure-stage chamber 7 is preferably of cylindrical shape, and its wall 8 may be moulded or cast from a single block of metal simultaneously with the wall 2 of the vacuum chamber. It is closed against the external air or the working chamber 31 by a perforated nozzle plate 9. When according to a preferred embodiment of the invention (see Fig. 2) the distance between the point of the nozzle pin 6 from the nozzle plate 9 is so selected that the point of the capillary 17 does not fall into a gas-density node 11 of the infiowing gas jet 12 but, as shown in Fig. 2, into the density minimum 10, a relatively short nozzle distance is obtained.

Preferably, as has been illustrated in the schematic Fig. 3 showing a four-stage pressure-stage stretch, the nozzle apertures or capillaries 17 to 20, are blanked out of separate diaphragms 13 to 16 which are constructed as funnels or as cone shells of a cone shape progressively slimmer, i.e. having progressively smaller cone angles, from the outside toward the inside of the vacuum chamber according to their sequence in the pressure-stage, and nested in each other with their points extending in the direction of the corpuscular beam, and inserted into the partition walls 21 to 24 between the pressure-stage cham- 4 bers 28 to 30. It is of advantage for the nozzle diaphragms to be exchangeable individually or in sets. schematically indicated in Fig. 3 are the pump sets 25 to 27 which serve for the generation and maintenance of the required pressure conditions. Means are preferably provided for cooling the partition walls between the pressure stage chambers, more particularly the. innermost partition wall 21, and/or the nozzle members, as indicated schematically at 13 in Fig. 3.

The cone shape of the nozzle diaphragms is very favourable inasmuch as they may be arranged closely behind each other in the apparatus so that on the one hand the points of the nozzles may line in the periodical pressure or density minima, respectively, and the total path of the corpuscular beam through the pressure-stage up to the atmospheric pressure remains small, while on the other hand the stage chambers determined by two diaphragms each and arranged behind one another are enlarged outwardly in a radial direction and thus favourable conditions exist for the connection of the pumps and for the withdrawal of the infiowing gas. Furthermore the area of the comically shaped diaphragms, being largerthan vertical partition walls, will etfect good distribution and removal of the heat which is still developed by the inevitable straying (diffusion) of the corpuscular beam. The said features and advantages of the invention come decisively into effect even when only two pressure-stages are employed but they also permit the number of pressurestages to be limited to little more than two stages.

In one example of a treatment of a substance according to the invention, an object 33 (Fig. 1) to be pierced is mounted in the working chamber 31 on a support 35 so as to lie in front of the corpuscular beam 32 emerging from the nozzle diaphragm 9 in order that the irradiated portions 34 of the object may be evaporated and the desired bore produced.

In the apparatus according to Fig. l the vacuum chamber 1 and the pressure-stage chamber 7 are connected by means of the stubs 36 and 37 to the schematically represented vacuum-pump sets 38 and 39 which have a suction power determined according to the desired pressure differences. It may be advantageous in this case for the pump 38 which is connected to the chamber of lower pressure to be arranged to operate against the pressure of pump 39 which is connected to the chamber 7 and which in this case acts as a pre-vacuum pump.

Constructive arrangements may be made which make possible both an adjustment of the desired distance between the two nozzle diaphragms 6 and 9 and the fine alignment of the latter so that the capillary 17 in the nozzle pin 6 points accurately to the aperture of the nozzle diaphragm 9.

A further adjustment device is intended to make possible that the beam generated by any suitable source of radiation 4, for example by a known telefocus cathode or by a cold cathode, shall strike accurately the aperture of the capillary at the vacuum side and is given the direction thereof. One construction has been found satisfactory according to which both for the housing of the beam apparatus and for the housing of the pressure-stage stretch two spherically ground bearings 40 and 41 are provided which, however, have different radii of curvature and different centres of curvatures, the operation being etfected with the help of the spindles 42 and 43. When the centres of curvature are disposed in opposite directions, the radii of curvature of the two ground bearings may be equal if desired.

The holders 3 for the source of radiation 4 and the housing 2 of the vacuum chamber and of the pressurestage stretch are connected to each other at the flange 44. When using a different particle accelerator the pressure-stage stretch need not be altered, and more particularly no other high vacuum pumps are required.

It is advisable in the spherically ground bearing for the sphericalsurface to be formed with astep at the smaller diameter or to arrange for them'to tcarry there a screen ring of a width such that nolsuppontingrporticns of the surfaces project freely into the high vacuum and that any gas discharge accidentally there "produced ,can- -not leave any burning traces of theground surfaces; If the spherically groundbearing ;is.ilubricated with :a thin high-vacuum grease layer, metal Smay:slide.on metal, and the ground connection is then high-vacuum tight without the use of flexible bellows. Apart-from the simplicity and reliability of adjustment hy means of the two spherical ground seatings, this also involves the appreciable advantage that the constructional height of the apparatus may be kept relatively-small. V y

In an apparatus with apressure-stage stretch. and dimensions as proposed-by the-invention, the gasflfiow in the nozzle diaphragms adjoiningthe 'vacuum is reduced to a very small fraction-of the flow of .gas entering the vacuum when only .a..single..nozzle:iis..used, without .any important stray (diffusion). .loss .being produced. Frurthermore the pressure-stage arrangement according to the invention has the advantage that, because of the funnel or cone shaped construction of the nozzle diaphragms and the resultant enlargement of the pressure-stage chamber in a radial direction outwardly, flow conditions in the nozzles and in the individual spaces between the nozzle diaphragms are much more favourable than in the case of fiat pressure chambers between plane nozzle diaphragms. The individual diaphragms act, due to their conical shape, as gas traps, since the nozzle apertures at the apex of each diaphragm amount to only a small portion of the cross-section which is available for the expansion of the flow of gas entering through the pressure nozzle aperture.

In a pressure-stage stretch carried out in accordance with the present invention the total path from the vacuum to the high pressure is very short and as a result losses by diffusion of the corpuscular beam are small. Since furthermore the wall areas of the individual pressure chambers are very large due to the funnel shape or conical construction of the nozzle diaphragms, very effective removal of heat is obtained and adequate room is available for the attachment of pumping stubs of as great a width as possible.

While the nozzle diaphragm in contact with the high pressure may consist of a thin plate without appreciably more gas penetrating through the fine aperture than would enter through a longer nozzle passage, the nozzle in the inner diaphragm is preferably constructed as a long passage or as a capillary so that on the relatively long part within the capillary already a great pressure drop may develop and the pressure in the first stage chamber adjoining the high vacuum may already be fairly high. Contrary to the situation in the preceding high pressure range, the flow of gas in the low pressure range is strongly reduced by a longitudinal extension of the nozzle. On the other hand, however, the corpuscular beam is not materially affected since the productzpressure times path length which determines the diffusion of a corpuscular beam, remains small owing to the small pressure.

A considerable advantage as regards the manipulation and manifold application of the device for leading out a corpuscular beam into the atmosphere is obtained by the proposed exchangeability of individual nozzles or of a set of nozzles. For this not only permits nozzle diaphragms which have become damaged in the course of time to be replaced by new ones in a simpler manner but also diaphragms of difierent nozzle apertures or shapes to be applied for difierent uses. For example, when it is desired to produce with one and the same device beams concentrated to different cross-sections, suitable diaphragms and corresponding nozzle diameters are required, independently of how otherwise the diaphragms may be shaped. The nozzle diaphragms may also be adjustable relative to each other individually or in sets. For instance,

electrostatic or magnetic lenses for concentrating (focussing) :the corpuscular beam, thus supplementing any-additional electron-optical focussing elements which may be provided. For ;instance, a magnetic lens 45 may be .arranged in the vacuum chamber, as has been shown in Fig. 1. Alternatively, the :long capillary 17 maybe further increased in lengthand/or be widenedat the entrance and the nozzle pin 6 charged negatively so that an electrostatic lens effectwis produced and the current density of the corpuscular beam is isubstantially increased at ith narrowest point of the pressure stretch. The nozzle apertures may also form the }p.ole pieces of magnetic lenses.

The ,pumps for the individual pressure-stages are-chosen suitably amongst the pumps available; but for certain intermediate stages no particularly suitable pumps are readily commercially available at the present time. An adaptation may be obtained for example, by filling a rotary pump with oil of very low viscosity without regard to the vapour pressure thereof and operating it at a rate of revolution greater than the normal one. One may also, when employing multi-stage pumps, provide each stage with a suction stub and connect it with the appropriate pressure stage or cause the pump of each pressure stage to work against the next higher pressure stage. It is also within the scope of the invention when the pressure-stage stretch or the whole corpuscular beam apparatus is combined with the pumps to form a construction unit so that no pipe conduits throttling the suction output are required at all.

We claim:

1. Apparatus for producing chemical reactions, comprising a source for a beam of electrically charged corpuscular rays having an energy not substantially exceeding 200 kv., said source being positioned in a vacuum chamber, means for maintaining in said chamber a gas pressure of less than 10- Torr, a pressure stage stretch including at least one intermediate chamber, means for maintaining in each intermediate chamber a gas pressure less than atmospheric, a partition wall between adjacent ones of said intermediate chambers, said partition walls having small apertures, the partition walls being so spaced that succeeding apertures are positioned in the minimum density region of the gas stream flowing into said intermediate chambers from'the atmosphere, means for concentrating the corpuscular rays and the apertures being so aligned that the concentrated rays pass unimpeded therethrough from the vacuum chamber to the atmosphere to cause there said chemical reactions.

2. Apparatus for the treatment of substances with corpuscular rays, comprising a source of said rays, an accelerating tube under a vacuum of no more than 10- mm. Hg for the acceleration of the ray corpuscules to an energy not substantially exceeding 200 kv., a working chamber under at least atmopheric pressure, and a pressure stage stretch between the vacuum and the working chamber, said stretch including at least two pressure stage chambers and a separating wall with a relatively large aperture between adjacent ones of said chambers, the separating wall apertures being aligned to transmit said rays from the accelerating tube to the working chamber and the pressure stage stretch forming a very short transit region of intermediate gas pressure with minimum energy losses of the ray corpuscules in said stretch, the working chamber being in communication with the last one of said pressure stage chambers and the substance to be treated being placed into said working chamber in the path of the rays.

' 3, Apparatusfor the treatment of substances with core puscular rays, comprising a. source :of said rays, an accelerating: tube yunder a vacuum of no more than 10* mm.I-Ig:for the acceleration ofthe ray corpusculesto an energy not substantially exceeding 200 kvz, a working chamber under at least atmospheric pressure, and a. pressure stage stretch between the vacuum'and the working i for adjusting the .distancebetweenthe holeswherehy the second and succeeding holes are pQsitionedin-a gas 'density minimum of :the gas jet; streaming into the interchamber, said stretch comprising at least one intermediate vacuumchamber positioned-between the accelerating tube vacuum and the working chamber pressure, a vacuum pump connected to each chamber and continuously pumping ,ofl? gas coming into the pressure stage stretch from the Working chamber through-a series'of holes positioned along a commonaxis, partition walls between said chambers,'the first partition walladjacent the working chamber i being asubstantiallyflat and thin diaphragrnhaving the e i t first one of said holes, each of. the following partition walls having-acentral cone pointing toward the first partition wall with the. holes at'the apex of the cones, means mediate chambersthroughpreceding, holes, all hole dis-. tancesbeing inthe 'samelorderofmagnitude as the hole diameters and the substance to be treated being placed into said working chamber in the path of the rays.-

References Cited in the file of this patent i UNITED' STATES PATENTS I Sinding-Larsen Dec.30,1919 i