US594036A - Roentgen-ray tube - Google Patents

Description

'H. L. SAYEN. RGBNTGEN RAY TUBE.

(No Model.)

- Patented Nov.` 23, 1897.

ATTORNEY.

WITNESSES JN, a

Q O O UNITED STATES PATENT OFFICE.

HENRY LYMAN SA'EN, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR T0 THE QUEEN d'. COMPANY, OF PENNSYLVANIA.

ROENTGEN-RAY TUBE.

SPECIFICATION forming part of Letters Patent No. 594,036, dated November 23, 1897.

Application led April 29, 1897. Serial No. 634,319. (No model.)

To all w71 0111l it mf// concer/1..'

Be it known that I, HENRY LYMAN Saran, a citizen of the United States, residing in the city and county of Philadelphia, State of Pennsylvania, have invented a new and nse ful Improvement in High-Vacuum or Roentgen-Ray Tubes, which improvement is fully set forth in the following specification and accompanying drawings. xo Myinvention relates to high-vacuun1 tubes more especially used for the generation of X- ra-ys,(Roentgen rays;) and :it consists of a novel method of providing the same with an .automatic and rapid adjustment for the presx 5 sure of the gas' therein.

It further consists of novel .details of construction, all as will be hereinafter fully set forth, and pointed out in the accompanying claims.

2o As is well known to those skilled in the art, the gas in 'a high-vacuum tube, being rarefied to such a high dcgree, is ordinarily in avery unstable condition as regards presr,

sure. Continuous use of a tube seems to de- 2 5 crease the pressure of the gas therein, so that in time it is impossible to get any current through the tube4 at all, since the conductivity of gases at these low pressures decreases with the pressure. It is also known that the lower the pressure is in a tube the greater is the penetrability of the light generated, wherefrom it will be seen that itis essential to have Y a tube in which the pressure of the gas therein can be altered at will and stay where rst put.

3 5 For instance, in an X-ray picture of the hand contrast between bone and iesh is much better when the pressure of the gas is greater, while in locating foreign metallic bodies in the trunk it is desirable to have greater penetration and consequent-ly less pressure. To overcome the diiculties hereinbefore stated, tubes have been constructed Witha bulb lconnected with the main tube and containing potassio hydrate or other similar material which is capable of giving off gas on heating and the regulation effected by means of a spirit-lamp placed under the bulb. It 'has further been suggested to use a resistancecoil around the aforesaid bulb, obtaining the 5o necessary heat by an auxiliary current passhigh-vacuum X-ray or Roentgen-ray ing through the coil. In these forms of tubes regulation not only lacks automatic action, but is exceedingly diiicult, for the following reasons:

First. Experiment has shown that the ma- 55 terial in the bulb must be used in a verysmall quantity in order that it will be possible to manipulate the auxiliary source of heat to cffect the desired change in pressure. This small amount of material is incapable of ab- 6o sorbing the gas given olf from the main tube i n case of its getting hot from excessive current, and the conductivity of the main tube increases, allowing it to absorb more and more current until disastrousresults are produced.

Second. It is almost impossible to keep thc pressure of the gas constant, and, as a very small change in pressure makes considerable difference in the penetrability of the X-rays, consequently an exceedingly minute change '7o in temperature is often'more than necessary to produce the desired result.

Figure 1 represents a vertical sectional view of a Roentgen-ray orhigh-\-acuum tube having attached thereto my improved device for automatically adjusting the pressure of the gas therein. Figs. 2 and 3 represent side elevations of modified embodiments of the .principle of my invention. Similar letters of reference indicate corrc- 8o spending parts in the figures.

Referring to the drawings, A designates a tube,

which is, except as hereinafter specified, of

the usual construction, said tube having the 8 5 high-vaeulrm chamber B and the conductor C leading into a portion thereof and communicating with the conductor D,to which theelectrode F, of aluminium or similarmaterial, is attached.

Gdesignates the other electrode,of platinum or similar materiahwhich has the conductor ll leading thereto, said conductor beingattached to the conductor L, which extends to the exterior of the tube, said conductor L having the conductor N attached thereto exterior-ly of the tube. The conductor N has a branch N' leading into the extension P, which latter opens into the vacuu1nchan1bor Q.

R designates a chamber, bulb, or pocket roc jumps again from A which acts as a'v gas-prod ucing means and extends into the chamber Q, though out of communication therewith, and is filled with potassio hydrate or other suitable material S,

said bulb opening into the passage T, which ing therefrom, said conductor having an extension X leading to the clip or support Y.

Z designates a conductor provided with the terminal Z' and which is pivotallyT attached to the clip Y, which is suitably supported, so that the distance between said conductor Z -and the terminal or branch A of the .con-

ductor C can be varied as desired.

The function of electrode U in vacuumcharnber Q is to heat the chamber R by molecular bombardment should the current take the circuit Z' Z V Q N' N.

The main tube A is exhausted through the nipple I to the highest vacuum obtainable with a mercury-pump, during which operation the chamber R is kept warm by the current from a small ind uction-coil, which is connected therewith,the current passing through the circuit X V Q N' A3, the chamber Q having been previously exhausted the desired amount through the nipple I. After sealing off from the pump the chamber R is allowed to cool. l

The operation is as follows: Cis connected to the negative pole of the induction-coil or other suitable source of current and A3 to the positive pole. The resistance of the chamber l?, to the current is practically infinite, and the current jumps across the gap A Z, taking the path of the circuit Z' Z V Q N N. This heats R, causing it to emit gas through the passage T into the chamber 1S until the pressure of gas therein is sufficiently increased or the vacuum reduced, so as to allow the current to take the path through the main tube B in preference to jumping across the spark-gap A 'l'. Immediately then R cools and reabsorbs the gas, and the current to Z because of the decreased conductivity of tube l. It will be seen, therefore, that there will be an intermittent current through chamber Q, due to minute fluctuations in the pressure in B, serving to keep R at the desired temperature. It the distance from A' to Z be increased, the resultant pressure in l; will be less be cause of the increased resistance of the circuit A Z' Z, &e.

Neither of the obj ectionshereinbefore mentioned is inherent to my'form of tube, because owing to this immediate regulation it' -is possible to use more potash S in the bulb 7o R, and when the current usedwith my tube is excessive the extra gas evolved is absorbed by S, which coolsimmediatelyon the lower-4 ing of the pressure in the tube. The limit thenof a tube equipped in accordance with my invention is the melting-point of the platinum-plate, and if we provide means for getting rid ofthe heat by conduction or other- Wise and immerse the tube in oil to prevent sparks from pun'eturing the tube we have 8o practically no limit to the amount of current which can be used, and consequently no limit to the light produced.

It will thus be seen from the foregoing that bymyinvention positive means are provided so that when' the conductivity of the tube decreases, due to an increase of vacuum, more current takes the path of the shunt-circuit and sends gas into the tube, or vice versa, and it will be evident that I need not neces- 9o vsarily be limited in every instance to the exact means which I have shown and described in the present instance, but reserve to myself the right to make such changes as will come within the spirit of my invention.

In Figs. 2 and 3 I show modifications of the principle of my invention, the tube B' in' Fig. 2 havinga high-vacuum chamber F' and the electrodes E G' therein, the latter being connected by mea-ns of the conductors 1) Il', roo respectively, with the conductors C' J. L'V designates a tube located adjacent the tube E and filled with potash or similar material, said tube L being supported from the tube B' by means of the neck L2. M' designates :o5 a resistance-coil wound around the tube L and having a branch K' leading to the conductor J', the upper portion of said resist-- ance-coil having a branch N deflected to-V ward, but disconnected from, the bra-uch N2, 1ro and the latter being connected with the conductor C'.

In the construct-ion seen in Fig. 3 the-high- Vacuum tube and its adjuncts are subst-antially the same as in Fig. 2, the tube L contain- 1 I 5 ing pot-assic hydrate or other suitable material and being supported bythe neck L2 from the tube Il and being provided with a conductor A2, the latter having a branch deflected toward, but disconnected from, the conductor 129 N2, while the lower conductor B2 is connected with the conductor A2 and has a branch D2, which leads to the conductor J There is an annular chamber Y around the tube L,which is partially exhausted of gas, so that the current in taking the path of the circuit C2 Ae B2 D2 J heats the tube L', due to the resistance of the gas to the current.

I do not desire to limit myself to the use of my method and apparatus in connection with 13o X-ray or Roehtgen-ray tubes, but may use the same with any vacuum tubes 0r bulbs.

l-Iaving thus described myinvention, what I claim as new, and desire tossecure by ,Letters Patent, is-

1. As a means for varying the pressure in a high-vacuum tube, a main circuit for operating the tube and a shunt-circuit for varying the pressure.

a vacn u x11-chamber, a bulb containing potassic hydrate or other suitable material located therein, but out of communication therewith, a passage leading from said bulb to said highvacuum Itube, and a shunt-circuit arranged in proximity to said bulb.

In combination with ahigh-vacunm tube, a passage l leading therefrom, a bulb Rconiaining potassic hydrate or other suitable inatcrial therein, in communication with. said passage T, a vacuum-chamber Q, having an extension 1, in which the conductor N' is located, a conductor V, having an electrodel attached thereto, and disconnected from said conductor N', and a conductor Z in proximity to but disconnected from the terminal A.

6. A device for varying the pressure of a high-vacuum tube, consisting of the passage T, the bulb R in communication therewith, and containing potassio hydrate or other suitable material, a vacuum-chamber adjacent to and disconnected from said bulb, said chamber having an extension P in which the conductor N is located, a conductor V also locatedwin said chamber and having a plate U attached thereto and a conductor Z in conimunication with said conductor V, and in proximity to but disconnected from the main circuit.

7. In combination with thigh-vacuum tube, a passage 'I' leading therefrom, a bulb R con- .toward or away from the terminal A'.

HENRY LYMAN sAifnN.

NVitnesses:

JOHN A. WIEDERSHEIM, WM. C. Wmnnasnnm.

' taining potassio hydrate or other suitable ma- DISCLAIMER.

594,036.-Hery Lyman Sagen, Philadelphia,Pa. RoENTGEN-RAY TUBES. Patent dated I November 23, 1897. Disclaimer led April 29, 1908, by the assignee, Queen and i Company. l

` Enters this disclaimer- A To that part of the claim in said specification which ,is in the following words, to Wit.:

1. As a mealns for varying 'the pre'ssure in a high-yaeuum tube, a main circuit for operating the tube and a shunt-circuit for varying the pressure.[0cial Gazette, May 5, 1.908.]

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