DE1648463B1 - Vacuum gauge - Google Patents

Description

1 2

The invention relates to a vacuum gauge. The invention is described below with reference to the drawing

with a filament cathode that emits electrons, explained in more detail. It shows

a F i g serving as a collector for the electrons. 1 shows a cross section through the various

Anode and an electrode serving as an ion collector of a triode vacuum gauge according to the

trode. 5 invention,

As is known, the usual vacuum gauges F i g. 2 another through the axis of the thread

According to Bayard-Alpert, an upper pressure limit of the non-cathode cross-section of the discharge

about 10 ~ ³ Torr. In the meantime, elements of the vacuum gauge according to FIG. 1 and

Time also show that by certain changes in Fig. 3 in an exploded view a

the geometry of the device the upper limit to io preferred electrode arrangement in a modified

about 1 Torr can be expanded. In an embodiment similar to that in FIGS. 1 and 2

Like execution there is an electron shown.

emitting filament cathode between two parallel Fig. 1 shows an electron emitting filament

and closely spaced cathode 1, which is arranged so that they are axially in

Electrodes, one of which is used as an electron collector 15 through a pair of parallel ion collectors 2

gate anode and the other serves as an ion collector. and a pair of parallel, as an electron collector

Since electrons run in a straight line and perpendicular to the serving anodes 3 limited space. Every

Move the plane of the electron collector anode, the anode 3 has the shape of an L-shaped strip

however, ions are formed on their way and both are attached to a perforated plate 4, the

to the ion collector on the filament cathode meet 20 through the space mentioned to the ends of the

can, since it extends substantially at a right angle structure, which is shown in FIG. 1 not cut

move to the ion collector. Through this ion- are represented. The ion collectors 2 are characterized by *

The thread is damaged by bombardment, in particular a wire or strip 5 is electrically connected. *

which if he has a coating of at low temperature Fig. 2 shows a longitudinal section along line A -A

temperature-emitting material, and it is 25 of FIG.

there is also an early deviation from the matically shown electrode arrangement. The up

the linearity of the pressure-flow characteristics of the building is partly controlled by an arm 9 via a boI

Vacuum meter at pressures of the order of magnitude of zen 7 and a number of ceramic insulators 8 ab-

1 torr. supported and on the other hand by a similar,

In order to determine the linearity of a vacuum gauge up to the 30 only in FIG. 1 shown, second arm 6 via a

type of high pressures are the following bolts 10 of the same type. Bolts 7 and 10 are supported

Conditions to be met: a perforated plate 11 serving as a base plate as well as

a) The geometry or geometric arrangement of the two ion collectors 2. The further element must be such that the electron paths trode pair, namely the anodes 3 and the Fadenmit the pressure does not change significantly. 35 cathode 1 are on the plate 4 or a bracket 12

b) The sensitivity of the device must be small. * ¹³ _A ^™ ά ceramic Abstandverglichen by the reciprocal value of the ^high-h f ^lter * ⁴ stored. The anodes 3 are to be measured ^{[eW (€ l} \ f ™ ^Bolze with the Lochsten is pressure. This is sealed by plate 4. the filament cathode 1 is the distance between the spatially by ernen to the console loading 12 belonging filament cathode and the electron collector * ° sprung end portion clamped reduction 15 with which the yarn 1 acts welded. the arms 6 and 9 serve the same

, _ ", τ,," η- τ ^ Jx- as electrical leads to the filament cathode 1,

c) The Ionenko lecturer must be arranged in such a way, _and ⁵ _{via attached to the jew} f _{me console 12th}

that the effectiveness of the ion uptake would take place via _welded angle pieces 16 and 17 the entire pressure measurement remains constant. Since the _{45 tronensammler serving} anodes 3 are to take over * probability em ion, with _dunes ^ _{dgr hole latte4 welded} en wire 18 to the pressure grows, the geometrical arrangement _{at a constant pot} must be maintained ential and the ion-order of the device eme consumption of all positive _{KoIIektoren 2 over an O} ° _{mht 19 The basic p} i _at te

T ^ aTT? ^mo $ ^lc * l ™: ^Prak * ^lsc k ^bed f ^tet 11 is grounded via wires 20. The two arms 6

This means that the ion collector must be large, m _{and 9 do not} end ^ _emer ^B ^ _{6n bearing plate}

with respect to the filamentary cathode. _{from GlaSj which} ^ _explored ^ _erli | _hen connection

For this purpose it is characterized by vacuum clamping.

meter of the type mentioned according to the invention. In the embodiment according to FIGS. 1 and 2

by using a pair of parallel anodes as electrodes, the following relative distances are used. the

tronenkollektor and a pair of parallel electrodes 55 anodes 3 have a mutual distance of

are provided as an ion collector, and that the 3.2 mm, the ion collectors 2 have an opposite

the pairs are arranged at right angles to each other. lateral distance of 2.5 mm and the gap between

The filament cathode preferably has the adjacent ion and electron collectors in shape one straight, symmetrical through the box - carries 0.25 mm each. The ion collectors 2 are similar Area of extending wire. 60 den held at ground potential, although they were held by the

With such an arrangement according to the invention, ceramic spacers 8 from the base plate

There is the advantage that an ion bomb bar is isolated, and the ion current is

dement of the filament cathode practically avoided or strengthening of the current carried by the wire 19

is at least very substantially reduced. measure up. The filament cathode 1 can be set to 35 volts

According to a preferred embodiment, the maintenance 65 and the anodes 3 are set to 250 volts. Dialing If the filament cathode is a platinum-rhodium alloy above an appropriate arrangement with a coating of an oxide one was written on, is the essential, for the relative used rare earths of low work function. Electrode dimensions and the relative voltage

Claims (6)

3 4 The essential requirement is that these are also within the range of these difficulties an electrostatic field, so that a thread from a platinum lo% - Development should result in such a way that rhodium alloy with a coating of a a) the ions to the ion collector instead of against oxide rare earth, in particular a cathode are moved, the yarn ⁵ and yttrium oxide, is used. This combination ,. , _ . _{1 T} , ",,. c gives a cathode of less effort b) the potential at the ion collector is not a control _{or a substrate with a high} melting point. _The ^ _{work function} by acting on the free passage of the electrical enabling low Arnen from the filament cathode to the electron beitstemperatur ensures that the evaporation exerts collector. _{lo the} thread pad is kept sufficiently small, For a vacuum gauge with the above-mentioned compared to the cathode gauges used up to now Geometric distances and types of electrodes, a life potential extended many times over, to achieve a satisfactory working duration of the system. Next is through established a heating current for the cathode 1 using a noble metal alloy of about 2 amps for the required burnout 15 non-burnout thread. Also is Controlling constant electron emission currents the cathode of the risk of "poisoning" less was needed. From the above values, exposed than other commonly used that the ratio of the voltages to the incoming cathode. Anodes and the cathode is about 7: 1. While although a device according to the invention like it this ratio can be seen in the case of slightly different 20 on the basis of FIG. 1 and 2 was described as May change geometric arrangements, should it prove extremely useful, is shown below for any particular arrangement close to its opti- hand fig. 3 which are kept a preferred design value. If it does not manifest in an exploded view, one is light, the heating current of the cathode thread can be described as a further possible embodiment. Ground up Fig. 3 additionally shows at least twice the desired 25 the same elements as that 2 amps rise to the same level control previously described embodiment, with the of the electron emission current. If the filament cathode is marked with Γ, the ion collectors with 2 ', If the ratio changed too much, the anodes with 3 ', the perforated disk, which the the electron flow finally carries completely under anodes, with 4 ', the base plate with 1Γ and are broken even if the current through the 30 denotes the ceramic spacer 14 ' Cathode is increased to a value at which they are. The ion collectors 2 'are burned out flat, however, formed compared to the cranked forms of the It has been found that the lowest pressure, in FIG. 1. This is achieved by the shallower depth of the ceramic, the current-pressure characteristic of the device spacer 14 'compared to the spacer is linear from the tension on the cathode thread. The facility also has to hang. The reason for this is that a Bombardie tensioning of the thread Γ two flat end plates 21 and the anodes with electrons of relatively high a single S-shaped tension spring 22, which keeps the energy content for the generation of X-rays thread aligned during operation. For leads that hit the ion collectors and one of the spring 22 is cause high working temperatures from the release of photoelectrons. This 40-holding nickel alloy used, both the effect is at pressures below ^10-4 Torr required electrical work flows and noticeable. However, it can be switched off when the bake-out temperatures have grown, which the vacuum meter is to be assigned to by lowering the anode voltage to 50 volts and applying the vacuum device to which the voltage on the cathode thread is lowered to 7 volts. A white. In this way, the tension ratio 45 teres additional feature of the embodiment is retained, so that the field distribution is unchanged according to FIG works linearly from 10 ~ ^{6 Torr.} of the four ceramic columns are provided.
These voltages are particularly suitable because, in spite of an anode potential below 50 volts, the sensitivity of the device decreases rapidly from case to case with a vacuum meter of the type described. With easy to manufacture, which is essential for achieving 50 volts at the anodes, the sensitivity of the device's reliable and repeatable pressure current is still 30% of that of characteristics. It can withstand a baking, 250 volts, while the potential is only 20% of the originally as required sprünglichen to about 450 ⁰ C and a degassing value. 55 by eddy current heating to about 850 ° C, without The pressure range of the described vacuum - that a loss of geometric accuracy in meters is roughly between 1 and 10 ~ ⁶ Torr. To be taken when purchasing. The invention such high pressures are subject to z. Currently available creates a robust, precise and in its geo- possible cathodes of destruction if they are easily reproducible in the metric conditions Presence of for example water vapor or 60 device. Working oxygen. As a result, the use was x> + + ■ · u Generation of high pressure vacuum gauges in general patent claims: their use in inert or inactive atmo- 1. Vacuum gauge with an electron spheres limited. It is therefore desirable to have a transmitting filament cathode, one as a collector for To create the cathode, the oxidizing or other 65 the electron serving anode and one as withstands harmful atmospheres without an electrode serving as an emission ion collector loss by changing the coating or characterized in that a pair of parallel Damage to the thread base due to oxidation. Anodes (3) as an electron collector and a pair parallel electrodes (2) are provided as an ion collector and that the two pairs are at right angles are arranged to each other. 2. Apparatus according to claim 1, characterized in that the thread cathode (1) is symmetrical by the ion collector electrodes (2) and the electrode collector anodes (3) runs limited area. 3. Apparatus according to claim 1 or 2, characterized in that the filament cathode (1) has ίο a wire made of a platinum-rhodium alloy, with a coating of a rare earth oxide of lower work function. 4. Device according to one of claims 1 to 3, characterized in that the thread cathode (1) is provided with a device (15; 22) for tensioning. 5. Apparatus according to claim 4, characterized in that the device for tensioning is an S-shaped spring (22). 6. Device according to one of the preceding claims, characterized in that for the Electron collector anodes from a perforated disc (4) used upstanding metal strips (3) are, the perforated disk between the ion collector electrodes (2) and parallel to this is arranged. 1 sheet of drawings