DE1539835A1 - Method for spark control for spark chambers and device for carrying out this method - Google Patents

Description

PATENT ADVOCATE. _ - DR. HAN8 ULRICH MAY I O O α Ο 0 D

Β MONOHS S. OTTO8TRA88E 1

Phone coeio ooaoaa B.2107.3 Munich, November 25, 1966

Dr. M./Eh

C-1-P-140/422

Commissariat a 1'Energie Atomique in Parle / France

Spark control method for spark chamber and device to carry out this procedure

The invention relates to a method for spark control for a spark chamber, for the visualization of fl parts as well as X-ray or y-photons is used, as well as devices that use this method.

A spark chamber of a known type, as described in the French patent application "Detecteur de partloul · · ¹ * of April 17, 1964 by the applicant and shown in FIG The end is closed with a transparent disc and the lower end of which consists of a thin metallic cathode 6, e.g. aluminum foil can also be made of lead or stainless steel.

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Inside the chamber, which is filled with a gas, an auxiliary electrode in the form of a is above the cathode and parallel to it fine-mesh metal grid 12 and an anode U with a transparent even conductive surface, for example made of conductive Olaa, arranged.

If the detector A is filled with an inert gas, no image of a radioactive source can be obtained. If you oppose it an appropriate amount of an organic vapor absorbing the ultraviolet rays of the gas can be added in The presence of this source will generate sparks provided that the voltage between the auxiliary electrode and anode is carefully determined iat.

Every time a particle is detected by detector A, molecules of organic vapor are destroyed, but leads the sparking leads to a much greater destruction of them Molecules, from which eioh a limitation of the life span of gas-filled Detectors in spark operation result in

Let us now again consider the formation of discharges in the detector A under the action of particles. When x-ray or y «photons are allowed to pass through the collimator 10 and reach the cathode 6, they generate ionizing primary electrons between the cathode and auxiliary electrode) the generated secondary electrons go through this auxiliary electrode and penetrate the field between it and the anode, which is much stronger than the field between the cathode and auxiliary electrode. In this stronger field the electrons break the break "

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BATHROOM ORIGIMATE

tion of a cumulative or avalanche ionieation, which leads to Creates a spark and makes the particle visible.

If a spark between the auxiliary electrode and the anode ttl> «?« Pops » the capacitance, which depends on the electrode dimensions, is discharged between these electrodes. It should be noted that the resistor in series with the anode is chosen so that the time constant of the charging circle is sufficiently large that a new spark hardly occurs in the same place. This process therefore takes a certain amount of time, which is proportionate corresponds to a large dead time «which slows down the operating rhythm of the detector.

It has now been found that the use of a spark control device serves to improve the mode of operation of such radio cameras by reducing the dead time and increasing the service life of the tube. The purpose of the charge is therefore to create such a method for regulating the run and a device for carrying out this method.

This task is achieved by the method according to the invention This was solved by connecting a discharge tube parallel to the tree between the auxiliary electrode and the anode of a spark chamber and a rapid decrease in the impedance of these discharge currents which is triggered by the current flowing through the tree between the auxiliary electrode and the anode of the spark chamber so that the capacitance between auxiliary electrode and anode is discharged after triggering the formation of a spark and

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this spark is quickly suppressed.

The invention also relates to devices for performing this method. According to a first embodiment of a Such a device iot the discharge device of the control device for Punkenkanmern a spark gap with fractional Discharge (eolateur a decharge fraotionnee) and the dissolution β-organ a pulse transformer whose magnetic core is a Ferrite ring is.

The main advantage of using this control device (dispositif de pilotage) is that the process of discharging the capacitance between anode and auxiliary electrode as well the dead time is shortened and the rest of the destruction of the a part of the organic vapor forming the filling gas is slowed down, so that the life of the stirrer is increased.

It has been found that the mode of operation of the detector can still be improved can further improve significantly and in particular increase the number of sparks that can appear in a particular tent.

The deionization time of a spark gap is a big one The minimum value for the dead time is fixed, and the triggering pulse generated by the ferrite transformer, which triggers this spark gap, has an amplitude that increases too slowly over time, from which it follows that the point in time of the short base of the space between The anode and grid of the spark chamber occurs too much delayed, which increases the dead time even further. Eventually worsen calibrated to a relatively limited number (e.g. 10) of

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Trips the tripping parameters of the spark gap, and incorrect solutions occur.

According to a second embodiment of a control device for Spark chamber that uses dao method according to the invention is a vacuum tube with at least three as a discharge path Electrodes are used whose space between anode and cathode corresponds to the series arrangement of the space between auxiliary electrode and The anode of the spark chamber and a small resistor short- ^ closes after the vacuum tube has been made highly conductive by a transistor in avalanche position and one on top following secondary emission amplifier tube, where the transistor from that of the inhibition of the resistance at the moment of the occurrence of the one discharging the tree between the anode and the grid Spark occurring voltage is controlled.

Of the properties of these last-mentioned inventions Device selenium mentions the great response speed and extreme shortness of the dead time, whereby the detector can deliver a large number of sparks in a short time interval.

It was also found that the most favorable properties of the ignition device (organe d'amoraage) are based on conductivity the surface of the anode.

In the case of a right-angled prism with a side length b of the square base and a height of 1, the electrical resistance r with a specific resistance ο des

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Material between two parallel Reofeteckfläohen the prism »

^r - fr · I

The electrical resistance of such a prlamas is therefore independent of the side length of its square base, so άαΒ m & n. can define a resistance in the square (resistance au oarree).

For example, in the case of a radio, »nka» mer, dar® «sprouts.

Surface _

The anode has a ¥ iäea? Et * iul on about 5 kw ia square, the signal occurring at the auxiliary electrode is aaoli 150 ftanoSeconds, the sparks reached a mass flow of 3? Β A ₈ while “when this surface forestetandl about 7 k ^ cheats ₉ the same signal corresponds to a maximum tetrom of 1.5 A occurring according to SOO Sasiseslsundea «

According to the characteristics of the appearing on the auxiliary electrode of the spark chamber MNQ signal Ale Sündvorrlehtung a sufficient amplification factor _s besitEan the KurasohliiSestladungsstreoke read. If the resistance of the glaset is high enough, you can use a vacuum tube as in the second embodiment.

For further explanation of the technical details of the he » In the following there are two exemplary embodiments of the method according to the invention. The description refers to the attached drawings.

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1 shows a section through a spark chamber used according to the invention)

2 shows the circuit diagram of a first embodiment of the spark control device using the method according to the invention for spark chamber

Fig. 5 shows the circuit diagram of a “wide layout of such a structure Contraption! which also use the method according to the invention used and a better Ausnutsung a spark chamber enables ι

FIGS. 4 and 5 are schematic representations of details of FIG.

So that the detector of FIG. 1 operates as a spark chamber, regulates the filling pressure of the gas and the anode voltage, which is stabilized must be so that one is in the presence of a radioactive Source gets a sufficient number of sound sparks to run in a few minutes to form a picture.

As is well known, molecules of organic vapor are every time «It does not stop when a particle is perceived, but it leads the breakthrough of a spark causing a much more extensive destruction of this vapor. As long as the total number of thermosole If the spark remains below a certain value, which depends on the dimensions of the chamber, one can determine the origin Restore the spark yield by swisohening the tension Anode and auxiliary electrode slightly increased. If «the spark chamber continues to operate after it has delivered the mentioned number of sparks has, the pictures contain some glowing disturbance points, and the Totreit uni3 are increased in order to avoid eie bu.

BAD ORfQfNAL

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In a case where methylal els organic vapor was used » became the composition of the Gaemisehung filling chamber A. underoucht by means of a hate spectrometer. Ea was found that the decomposition products of this vapor are essentially hydrogen, carbon monoxide and in smaller proportions Ethane, ethylene, methane and carbon dioxide are.

A lesser operation of a spark chamber leads to an increase of the pressure, and the reduction in the number of times when the voltage remains the same, is due to a lack of absorption of the iron a spark to watch out for ultraviolet rays.

If the conductive layer on the anode has a resistance of 3 kQ ₁ square, the charges of the capacitance between the grid and the anode flow out in about a microsecond.

^It has been found that the deleterious effect of destroying the organic vapor can be reduced by forcing the charges to flow through an external circuit after the spark has appeared. As a result, a spark gap with fractional discharge (spark gap) was used to bridge the gap between the auxiliary electrode and the anode of the chamber in the adjacent floor. . as soon as the discharge occurs.

In the following, the one in Jig. 2 described, equipped with a spark gap control circuit of the spark chamber.

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Corresponding parts are identical in different figures Provided reference numbers.

While the cathode of the tube A is connected to ground, the auxiliary electrode 12 is connected to a low voltage source NV via a resistor 18 and the anode 14 to a high voltage source HV ₁ via a resistor.

The control circuit shown is characterized by a spark diffuser 22 with fractional discharge, which separates the space between The anode and auxiliary electrode of the chamber in the if level is bridged » if this was triggered by the ignition device 24, the the discharge current occurs between the anode and the grid of the chamber.

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The current impulse appearing in the tube during dunking is transmitted to the spark gap by means of a pulse transformer 26 'whose magnet core is a ferrite ring 28, on which the primary winding 50 and secondary winding 52 are wound.

The spark gap has two fully formed main electrodes 37 and 58, between which intermediate electrodes 40 and 42 provided with a central channel are arranged. The metal tube 45 is a corona electrode which is connected to a high voltage source HV ₂ via a resistor 44.

One end of the primary winding 50 is directly with the grid connected to the spark chamber, while the other end has a

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The condenser 34 is connected to the anode 14. The first ending This Plinä * winding is also about the parallel arrangement a resistor 35 and a capacitor 36 of large capacitance connected to the ground with respect to the capacitor 34. The secondary winding 32 of the transformer is old on the one hand first intermediate electrode 40 of the spark gap and on the other hand with one of the taps of a chain of resistance 46,48,50, one distribution of the voltage on the base of the electrodes the spark gap enables connected. One end of the resistor 50 is connected to the end electrode 38 of the spark gap and connected to the anode of the spark chamber; the common point of resistors 48 and 50 is with the outer intermediate electrode 42 connected to the spark gap. The popular point the resistors 46 and 48 is connected to the secondary winding 32, while the other end electrode 37 with the second end of resistor 46 is connected.

The operation of this control device can be summarized as follows.

If a spark arises in the chamber, it carries out current going through the chamber sum occurrence of a voltage pulse with large amplitude at the 3ekundärwioklung 32 of the Tranafcrmator 26. In a few hundred nanoseconds, this amplitude is large enough that the tube 22 during the rise time of this pulse is ignited.

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Duroh use of the in Pig. 2 called device one can pretty raooh pictures obtained from radioactive sources.

A second embodiment of the application of the method according to the invention is shown in FIG. It can be seen in this figure, the arc chamber according to the bes A of FIG. 1. However, the anode TEHT ^ U of a glass pane _f the vorsugswelse on its underside a transparent conductive film 15 has doped tin oxide in the desired manner. This anode can be connected in the opposite circle by means of a conductor ring 17t which is attached to the circumference of the lower surface of the anode.

The grid 12 is connected to ground through a resistor 110 of small value (not very old a few tens of ohms). The cathode 6 is connected to the sliding contact 116 of a potentiometer 11Θ, since it _{connects the negative pole of a voltage source NV 2} to ground. By regulating the position of the sliding contact 116, the voltage applied to the space between the cathode 6 and the auxiliary electrode 12 of the spark chamber can be adjusted. Finally, the anode 14 is connected to a voltage source 124 providing a very high voltage _{via a resistor 122 of large value above 1MQ 1.}

The value of the resistor 122 becomes as desired Sparks prey set ..

The space swisohen anode and cathode of a vacuum tube type Tetrode 126 is parallel to the row arrangement of the space two the anode and auxiliary electrode 14,12 of the spark chamber and the

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Resistor 110 connected. The anode 12Θ of the tetrode is over a resistor 130 to the anode 14 and the cathode 132 of the Tetrode connected to the ground. The screen grid 134 dieeer Stir is one through a resistor 135 with the positive pole Hochspammngeq.uelle HV- connected. Βρε control grid 138 is with the negative pole of the spacing source HVg over the resistance 140 and a / part of the potentiometer 142 connected to this Pole of the voltage source connects to the ground. Dioees tax » grid 138 let furthermore via a capacitor 144 with the control « device connected. This control device consists of the arrangement of a transit gate 146 in avalanche protection and one Secondary season amplifier tube © 148.

If a spark is generated in chamber A, «wipe» appears the point of connection of the resistor 110 with the grid 12 and Hasse becomes an impulse B with a steep wave front · Dieeer then by the avalanche transistor 146 and the secondary emission amplifier tube 148. Ee Then a pulse 0 of large amplitude appears at the control grid 138, which lasts less than lyus. The impedance of the tube is very reduced »and the arrangement of space 12» 14 of the spark chamber and resistor 110 is curly unisex.

Fig. 4 shows the amplifier 146 $ of essentially one There is a transistor in X> avalanche circuit.

The common to the grid 12, not shown, and the "resistor 110"

same point is across a low capacitance capacitor 50 and a rectifier 52 connected to the base of transistor 54

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You can see that the circuit and emitter circuit of the transistor are isolated from the ground by blocking inductors 56 and 58. The collector of this transistor · is connected to the Kuit over the Capacitors 60,62,64 and a potentiometer chain 66 connected, which is the ground with the positive pole of a high voltage source connects.

By carefully choosing the position dee Söiileifkontakteydea Potentiometer you can achieve that the transistor in the avalanche » operation works, whereby a second, the same positive pole of the high voltage source HV * with the ground connecting Potentio = meter chain 72 regulating the polarization tension of the Baaie of the transistor and this polarization voltage determines the sensitivity of the transistor 54. The one from the transistor amplified voltage pulse appears »as above with the Emitter connected terminal 74, which is connected to the control grid 76 (Fig. 5) of a secondary emission amplifier tube » and the crowd.

Fig. 5 shows the amplifier 148, the essential part of which is included

and secondary emission tube 78 having a cathode 80 ^ a like

already explained, with the emitter of one in avalanche protection switched transistor 54 connected control grid 76, uafasst. You let over a resistor 82 and this one

far away a tete Zener diode «84 connected with the Maa ··. Dl · ·· Drilling tnfeJt / Screen grid 83, which is polarized via the potentiometer 85, a barrier grid 86 connected to the cathode, a dynode 88 connected to an intermediate point of the potentiometer chain 85 and one through a resistor 94 to the positive pole of one

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HooSiapannungsq, uella HTg imd via a capacitor 9S with Maaae Terlinden's anode 90.

The τοπ represents the arrangement of forrishtungen 14β and 143 Signais sraehoinen oinsrsoits between there? % aodi 33 and Mass and on the other hand swisahen io? Anods HEi do: e Measi®. Man can dahox · θίποο diaasr baidon !! »aiQEta with

It should be noted that b © i the! Reads? applied Sonaltmig the dynode with ü®m Steuergikter 138 d®z · ^ © toadenräiirs 12S übar d @ n 144 veybiiiiden igt.

a modification connects the anode 90 with dar

Control electrode diQsar Höare 126 üax · ®ia®a dia Biohtung dsa Anodane pulse isa

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Claims (6)

Patent applications 1.) Method for spark control for spark chambers, thereby characterized in that one parallel eiim space between the auxiliary electrode and the anode of a spark chamber switches a discharge circuit and a very rapid decrease in the impedance of these discharge streets causes, which are triggered by means of a round rotation caused by the current passing through the aforementioned space of the spark chamber, the capacitance between the auxiliary electrode is reduced and anode of the spark chamber cu discharged when the formation of a Spark has been triggered, and to undermine this spark quickly. 2.) Fmikenregclvorriohtung for Funkenkamaern iur implementation of the method according to claim 1 _e characterized in that the discharge path is a spark path (22) with fractionated ^ - charge and the ignition device eic pulse transformer (26), the magnetic core is a ferrite ring (28) (Fig. 2). 3.) Spark rule locking for spark cameras for implementation of the method according to Claim 1, characterized in that the Discharge streoke tine vacuum tube 128 having at least three Are electrodes, the circumference of which, like the anode and cathode, is arranged in series d * s space-wise help electrode and anode (12-14) of the Funkenkammsr (A) and ei & cs resistance tone low «value (110) kuresehlieSt after making the vacuum tube highly conductive " became through a transistor switched in avalanche protection (146) and a subsequent second remission amplifier rotation 009833/0117 ^ ° ^^ (148), the transistor being connected to the resistor at the terminals dta (110) At the moment of the occurrence of the capacitance between the anode and auxiliary electrode of the spark chamber Spark occurring voltage gee fcft * ;. b will 4 / ^; . ^ ikenregc ¹ 'device for Tunkenkamnmrn nftoh claim 3, characterized »that the dynode (88) (Fig * 5) of the secondary emj.aöioneverotärkerrühre (78) via a capacitor (144) with the control electrode (138) of the vacuum tube (126) dee KuxftchluB-kraioeo connected let (Fig. 3) 5.) Spark rule Torriohtunf for Jmiiim »e« nrn MMeI ΑΜβ ^ ΠΜ ^ ι 3 » This means that the anode does * 8 turk tube (78) with the control smooth of the Takuueröare (126) # · ■ KuÄchlußlcreleea connected via an Impuitaekehrtrftnefonuttor is. 6 .: Spark control device for spark chambers to carry out the « ^v * - rWahrem · narh Anepruoh 1, thereby knownAlchnut <! 'Ss'! ¹ S surface conductivity of the anode is related to the characteristics of the ignition device. 0098 33/0117