DE1951589A1 - Method and device for examining materials with the aid of ionizing radiation - Google Patents

Description

Method and device for examining materials with the help of ionizing radiation »

For a long time, ionizing radiation has been used to hit materials and, in particular, to determine a physical property of a material to be examined, such as the density or the relative composition, if the material to be examined has the due date, a specific type of material to be examined To give an example to which, however, the applicability of the invention is not limited, it should be mentioned that radiation measuring devices are already in use which make it possible to determine the concentration of a hydrogen-containing otoff, e.g. . of water, in a material to be examined, Z ₀ B _{0 of} a soil sample. ±> This determination and measurement of properties and features uses phenomena that are referred to below as a change in ionizing radiation. it's long been known that ionizing radiation, for "B _e n a! eutronenstrahlung, gamma radiation or x-ray! is altered by various characteristics of certain Ütoffe different itfeise _f and. that this phenomenon can be seen in practice through the

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consumption of- beam ungsmeßgerr th advantage can make "In the a.is here as mentioned case, the iuoderierung .. or Abbrerasung fast neutron by wasserstoffhal-term ötoffe" exploited to the ^ rmiutlung the _"presence;.! of moisture . .bathing and the moisture content to -er-. - "· - possible. For every person skilled in the art, there are further examples of., Physical properties that can be investigated with the aid of ionizing radiation, are obvious.

In the course of the recent development of electronics have two important areas for improvement for the

ψ Users of radiation measuring devices showed, and the development work of the manufacturers of such devices is proceeding in this direction which enable radiation measuring devices to be used outside of laboratories. Second, the increase in the extent of the use of such devices has led to the fact that the users of the devices demand constant improvement in the measurement accuracy , and this need, the industry through the creation of increasingly complex

. accommodating emerging electronic circuits »

Admittedly, the advances made so far have already resulted in a considerable improvement in usability and applicability - guided by radiation meters There are still certain difficulties with these devices. In particular, it has become common practice certain statistical restrictions with regard to the measurement technique in which atomic nuclei are used, and certain time and temperature-dependent drift characteristics balance the electronic circuitry in such devices by using a ratio checking procedure Until now, when determining a property of a material to be tested in such test procedures, that the relationship between the result of a test

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measurement of the change in ionizing radiation the material to be examined and the result of a previously or later measurement of the change in ionizing radiation determined by a reference standard, which is usually a sample of a material acted with a stable characteristic when the test measurement and the standard measurement during different time periods To be carried out, it is often difficult to ensure that the lines are changing the ionizing Radiation through the examined Jacobe and the reference standard reproduce correctly, and that these measurements do not lead to inaccuracies in relation to the ratio to be determined with the help of the measurements, because it takes time a relatively long time until the electronic circuit used in the measuring device has stabilized.

In view of the above, the task of the invention is to create a radiation measuring device for the non-destructive determination of a physical property or characteristic of a material to be examined, which automatically compensates for certain factors which up to now have led to a limitation of the usefulness of such devices _o To fulfill this task, the invention provides a radiation detection device and an associated electronic circuit to which the ionizing radiation changed by a sample to be examined and the reference standard is supplied, and which makes it possible to determine the relationship between the reaction of a first detector and the To determine the reaction of a second detector and thus to display the previously unknown characteristics of the sample to be examined. Here the electronic circuit is set up in such a way that the reactions of the two detectors are determined within a common upper range the, Z ₀ B ₀ in DAB On the other to the reaction of a -Detektors, used to the passage of the reaction of the ^":; to control the detector «, ■ -. ■".:. "« - -

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According to a further feature, the invention provides a method for determining a physical characteristic of a material sample to be examined under the action of ionizing radiation on the sample, in which a so-called test channel sample and a reference channel sample are simultaneously exposed to the ionizing radiation of a selected type of a common source, and in the case of the detector assigned to the sample to be examined and a detector assigned to the reference sample, the radiation emitted by the radiation source is supplied at the same time, which has been changed by the test or test channel sample or the standard channel sample. Then the ratio between the simultaneous xteaktionen of the two detectors determined as a measured value indicating the physical characteristic to be determined to achieve this effect, it is preferred according to the .Erfindung to use detectors that emit pulse trains, and 'the ratio de To measure r simultaneous responses by applying pulses emitted by the reference normal channel detector to a subdivision stage previously set to receive a predetermined number of pulses and passing pulses emitted by the examination channel detector while controls the amount of time required to collect the predetermined number of pulses in the subdivision stage.) .,

The invention and advantageous details of the invention Are in the following on the basis of schematic drawings explained in more detail using exemplary embodiments «,

Fig. 1 is a schematic diagram of the main parts; of a Strahiuiicsmeßgeräts according to the invention.

Fig. 2 shows in perspective the radiation source, the samples and the detectors of the device according to IPig. 1 enclosing housing construction. ■ -

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Fig. 3 is a perspective view of a Housing for a device for performing measurements of properties of the earth's surface.

Figo 4- shows a schematic section through the Device housing according to FIG. 3 shows a possible geometric arrangement of a radiation source, the tubes and the detectors according to the invention.

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Figo 5i 6 and 7 are similar to Fig aligemein _o 4, but showing other geometric arrangements of the main parts of the invention device,

Figo 8 is similar to Fig. 3, but shows a device with a passable into the ground

FIG. 9 shows a representation similar to FIG. 4 of the device according to FIG. 8, a geometric arrangement which is a detector built into a doride, which is built into the i-material to be examined can penetrate *

Fig. Iu is a schematic representation of a _{display device or similar} that can be used _{in the device according to Fig. 0 1}

Before the invention is discussed in detail in relation to the drawings, it should first be more appropriate to deal with certain factors that are related to the statistical conditions that play a role in the operation of radiation measuring devices the characteristic properties of the electronic circuits used in such devices _o This has already been briefly pointed out at the beginning, and it was found that these factors lead to certain difficulties which should be eliminated according to the invention »

The maximum level of accuracy that can be achieved with any measurement method in which an ionizing beam development is detected and / or changed, especially in the case of devices where the source of the ionizing radiation

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is a radioisotope is limited by the statistics of the energy emission. The probability of the emission of radiant energy at a certain moment depends on the fundamental binomial distribution laws that apply to randomly occurring processes and which, with certain restrictions, are due to the Poisson distribution Since publications such as the work "Radioisotope Measurement Applications in Engineering" by RP _O Garder and

Role ElIy, Jr. (Reinhold Publishing Company) are Otherweise where .statistischen ratios and statistical analysis methods are discussed in detail, should '■' - there are unnecessary to bring a detailed explanation here .. It should be noted briefly that such investigation procedures in cases in which the measured values are "obtained from pulse series emitted by radiation detectors, can be used in arrangements in which a physical characteristic of a material to be examined is measured " by determining the relationships between counting speeds and the property to be determined. If the counting speeds are known for two different values of the characteristic to be examined, the difference in counting speed, when divided by the difference in the characteristic to be examined, shows the increase in the calibration curve of the device in question. The standard deviation or the one-sigma value of the statistical distribution of the measured values of a specific measuring device, which is a measure of the optimal accuracy of the device, equals the square root of the counting speed divided by the slope of the calibration curve. Assuming that a single value of the counting speed is the true mean counting speed of the measuring device, the percentage error for the standard deviation or the one-sigma deviation can be expressed as the square root of the total count divided by the total count multiplied by 1oo. With a measurement count of 10,000, the percentage error for the standard deviation is therefore equal to 1 ^c / o. With a measurement count of loo ooo, the pro

centual errors for the standard deviation equal to 0.316% .

The meaning of this discussion of the statistical relationships to be considered in radiation meters becomes clearer can be seen if one looks more closely at the interaction between this factor and other factors involved in result from the design of the device «If a designer of such a device is looking for ways to improve the accuracy of such devices, there is a possibility is to change the mechanical-geometric relationships of the parts of the device so that it is possible to To influence the slope of the calibration curve «If, however, in the In practice, the limit value for the slope of the calibration curve has been reached, there is a further possibility for improvement regarding the measurement accuracy in an increase in the Measurement of the accumulated counter result. At a certain limit of the percentage error in the or «one standard deviation exceeds the practically achievable limit of the electronic and mechanical stability of the measuring device that of the statistical behavior of the radiation, so that with the help of an increase in the counter result No further improvement in the measurement accuracy can be achieved with each measurement · The upper limit does indeed play for the improvement of the measurement accuracy by increasing the counting result collected during the measurement Most of the radiation meters up to now have not been essential Role, so the importance of this factor was at the cases in question have already been generally foreseen, and in certain areas of application this is the upper limit has actually already been reached.

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: With regard to the second problem, which has already been briefly mentioned, it should be mentioned that the electronic circuit elements that are required to enable a measurement of the series of pulses produced by the detectors as a function of. of the ionizing radiation are exposed to a drift, which can be either a long-term or a short-term drift. A useful subdivision is considered to be those changes which in such a measuring device are considered to be long-term drift Intervals occur that are longer than one day of use o In. In most cases it can be assumed that the emission velocity of the ionizing radiation is essentially constant and that it therefore does not affect the long-term drift, so that such drift is generally due to aging phenomena in the electronic circuit and changes in the efficiency of the detector , is »Ks it is assumed that a short-term drift is primarily due to an increase in temperature of certain electronic circuit elements, which is caused by the destruction of energy in a circuit element, this energy must be supplied to the circuit element in order to operate hai - "th. Second, the short-term drift depends on changes in the ambient temperature. This temperature-dependent drift does not correspond to a linear function, and it usually contains a rapid and considerable change that occurs during the first two hours of operation and a smaller change that occurs during a longer period of time that occurs after a day of use lasts and .. therefore to be described as a long-term drift is »typical; u-devices of the mentioned Jtrt show a drift which during the first two hours of operation is in the range of about U, 5 ; »- and 1 / o , and which is about 0.01 , σ to 0.05 / o every hour thereafter. J amounts to \ ve :: n they are expressed as changes in the ζ ä.-il speeds ... ± i such a percentage change in the counting speeds can represent very large changes in the material to be examined, if one considers the

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- compares 9 occurring deviations with the statistical error.

The two difficulties discussed above have been addressed up to now by using a reference count ratio switched off. Even before radiation meters were used on a large scale, it was recognized that a frequent Calibration would be required if the equipment had a sufficient Degree of accuracy should work. Working with a reference counting result ratio should serve to determine the time intervals to extend between the required calibrations; a method is used here in which a counting speed measurement the properties to be determined are carried out on a sample made of a stable material with known properties in which the measuring device corresponds to a ratio between the measuring counting speed (measuring counting rate) and this reference counting rate (reference counting rate) is calibrated, and at which the reference or standard sample also in use of the "device is always available in the field.

It is true that this ratio method proves to be very square-shaped, as most of them are due to the long drift and mechanical change with regard to the geometrical relationships of the meter will be eliminated as long as these factors are both the reference total count as well as the total measurement count, yes result from the current «common type of application this relationship proceeding has significant limitations. Both the reference total count result and the measurement total count result are subject - as already mentioned - to statistical fluctuations. The study of the relationship between the two results is always greater than each individual counter result. the resulting scatter corresponds to the root mean square value of the two each weighted according to the size of the count result individual scatter. In practice it has been found to be

proved expedient to require that the ^ aigma deviation of the reference total counting result must be smaller than the 1-sigma deviation of the Keß total counting result. when a considerable reduction in the accuracy of the resulting ratio becomes one in both the initial calibration up to now Worked radiation meter as well as during its use. - -. . "" - ..:.

When using this method, most reference counting speeds are chosen to be within the The range of flow counting speeds applicable to the material to be examined falls, since the standard deviation corresponding to the square root of the total counting result changes, for statistical reasons it is preferable to collect nine times the total measurement result, In order to determine the reference total counting result, you therefore need the Nine times that required to take a measurement for extraction of a count result »with regard to the actually available" usage time This quickly turns into an untenable situation, and it is now common practice that'in the exception of extreme situations a deviation of 2 sigma is used, so that the duration of obtaining the reference count result only corresponds to four times the period of time that is required for the Obtaining a measurement count result required. ~ '

Admittedly, such 'apparent waste of usable operating time' is undesirable, but it can be permitted if it is not necessary to 'repeat the acquisition of a reference counting result' too often during a certain period of operation. to be where the standard deviation "is large compared to the short-term drift, need a ¹ Bezügszählergebiiis only once during each use day s determined '· when using

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a higher short-term drift working devices it may be necessary to obtain a reference meter reading twice a day or to be determined more often.

If you have higher requirements with regard to the accuracy of the measuring device, you can use a. Reference counting result only after two hours have passed after switching on of the device, because the initial drift speed can predictably change during the time it takes to determine both the reference count result as well as the measurement counting result, whereby this deviation is greater than the statistical

ί see change during the election period «■ the user of the device must therefore wait until the drift speed has stabilized at a usable value that is below the statistical limits of the measuring device«

'From the foregoing discussions, the most extreme Limits can be seen that arise when using such measuring devices. It is regarding the construction of such a measuring device thus reaches a point at which the -required accuracy requires that a reference counter- The result is then determined between every two keß counts becomes after the mentioned, initial waiting time has elapsed after switching on the device, and that therefore four Fifth of the total operating time is lost. Using such a radiation meter for measuring purposes becomes impossible in practice because the drift is greater than the statistical error,

With reference to the drawings, it should be noted that It has now been found that the difficulties due to the drift can be eliminated by two measures can, according to which in the construction of a radiation meiigeräts The greatest possible commonality is sought in the electronic circuit, in order to ensure that everyone is in a hurry Device to maintain an even drift, and "according to which the reference count result and the measurement count result

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within the same upper area bsw “at the same time determined Yverden. .oomit includes - according to the JirfiricSung an eiiizi · e operating time span both the obtaining of the in combination with one or more ',, suitable sources for an ionizing otra.:Iunp: un:'. ^ a suitable jjetfilitoren -.nsciceverrichtung: used, which is so eirericLret that. you a direct; ... essun ^! 3- of the '7erh.' ^: ii; n.icües between the xiozu ₀ szi. '. Lieryebnis and (..t :: iei .. E ^ hlerf-'ebnis cr-

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of an invention ^ s ^ em-V.-en ^ e ^ öür ^ ts ε / ιί "a belitbigeu. ±> .: ae r ^ an ionizing /j" Crj^IuiJ._, z, .z, _a der · . «. Rt, derr ^ ie, the intensity or the j .... enue, are based on Jvanii, the i'-tr / experienced ke * ^ se are learning, at de :: en:,:! υ eii ^ -r sol-, cen ot-rc-iij-ui:.; ^. ' _earbci "oet v / i;: · '.., acc"_' / ir- '' die ürxi :: ^ u.- '~ ^: sun-: chst bez.irlicL -in ^ -s ^ .e ;, ror; ^: "ts Vise rubbed, in which the change aer otra'r.Iur.s; -duroi- eiae i.-oderi ^ run ^ is be'virlct ^ from tieuuronen» in this j'all v-'erder. schi elie. ..c utrons

in samples of about unte: -suchenden i ...- ^r: i ^-: ri8l: ·: <-: _;:.! - :. ·! eitet and durc 'a p.iTsi-ialiscnes iv-erkr-al cz- ;; "a property of r.uc, x; -rials' -.- oderiert, and z?; ar in ci ^ c. ^ t ^ rpiocberi x'aj.1 .- '.:. uj.-oh a "." ar-serstc, "f Laitiren, .er tandtcii des ... ateriais, go .'- ·.!: ΐεη i ^r n _v : sa ": e oaer" cherr: isc'-e -.outrcnen jx '; ^:: li ;, die: it .. help

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w-π: a i;: i -.vesexi-J-iichei- ^ ¹ !. ^ J.ο -arti c -cctr? .LJ-UJi ₁ : the i-aterialproLen. to ^ ". 7.V'.rleict-.-;.," v "he -they -ijs nucn tm ei ^{l läu:;...} e · iden ir'.uiilen erx'crae: is rlioh, vriro. e :; before; e ogen, oei one: inventions' ^ en ^ ßen i; .ei: '- v "t the in i <': i. 1 and 2 darre-steep ürt a - ^ uelle Il- i '"' lr scr hurry .. t ,: to provide ronen, in which it fell · - preferably - a"ceiö'netes elementary or isGtonisc'jes La to rial like 'Kadiuni-B-eryllium' or Americium-.jerYlliufii hanaeit- _o

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195] 589

To get a direct measurement of the relationship between de: -; ^ ezUjSzänlergeDiiis and the measurement counting result and the G-ewiiuiung the two'Zählergebuisse during the same time span, the measuring device includes according to! '' ig. 1 is a bniskanalc both i..eßzählergebniskanal and a .xsezugszähler ^ The iaeßzählergebniskanal comprises a first iJetelctor D1 and its associated '..Al amplifier, the detector D1 supplying pulse trains, and a pulse Farme! ^ POE1 circuit, such as _o a discriminator for shaping the amplified pulses output by the amplifier A1. Correspondingly, the reference count result channel comprises a second one. Detector D2, an amplifier A2 and a pulse shaper circuit PS2. According to the invention, the influence of the drift on the determination; the physical properties of a sample is reduced to an iViiniiaum with the aid of the device according to FIG. 1 in that the amplifiers ΑΊ and A2 and the pulse shaping circuits PS1 and PS2 are matched to one another. In addition, the current required for the operation of the circuit elements of the two channels is taken from a common current source, so that differences in sensitivity are avoided, which would otherwise result from differences in the supplied currents.

To ensure that the detectors DI and D2 comprehensive detectors in the right way to the change in the from. the source 10 released ionizing Addressing radiation by the physical property to be determined is preferred according to the invention a device is provided which makes it possible to investigate a sample 11 from a material of unknown Properties and a reference sample 12 made of a material with known properties to be that of the source lü exposed to ionizing radiation are, i'erner are the examination channel detector D1 and the Reference Channel Detector 132 arranged to read the sample to be examined 11 '"or *" .that by the reference sample absorb changed radiation «, If the from the source 10

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outgoing ionizing radiation, to which address the detectors D1 and D2 is formed by fast neutrons, which are transformed by the samples 11 and 12 into thermal neutrons, the invention provides the arrangement of a suitable screening device, for example _a a plate l'j> from Cadmium between the radiation source 10 and the reference sample 12 before _o . The cadmium plate 13 does not form a barrier for fast neutrons, so that the fast neutrons cause an irradiation of the reference sample 12, but the cadmium plate shields the detector D2 from the thermal neutrons which, when encoded, lieutrons through the sample to be examined. 11 = In addition, the shielding IJ prevents the examination channel detector D1 from detecting thermal - ± neutrons that have been moderated by the material of the reference sample 12, so that independent operation of the Jkeß channel and the reference channel is guaranteed.

So that the "physical property of the sample 11 to be examined can be displayed, which is to be determined non-destructively with the aid of the device according to the invention, the monitor also includes a display device 14, ax connected to the detectors D1 and D2 and responding to them that the detectors detect the radiation changed by the sample 11 to be examined and the reference sample 12 in order to display the previously unknown property of the material of the sample 11 to be examined between the Heaktion of the first detector ^D1: Calculate and the reaction of the second detector D2 DA ■ due to that the ratio between the equilateral responses of the two detectors wirdo measured Su comprises this purpose _#, the display device 14 is preferably a Un> .erteilungsvorrichtung 15 , which the pulses of the reference channel detector D2 after their amplification by the Ver stronger A2 and theirs. Shaping can be supplied by the pulse shaping circuit Pü2. The dividing device 15 can be any suitable digital one

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Collector, a slider ^r ; ister, a ring counter circuit or some other known basic computer circuit, provided that the circuit is so designed that it is fed a predetermined number of pulses from the detector 1) 2 through the amplifier A2 and the pulse shaper circuit Jrö2 can, until it emits an output pulse. The number of the designation "distribution device" for the "collecting device 15 is justified further below, the entire mode of operation of the device is explained in more detail" -

The display device IM also includes a suitable atter 16 which is connected to the investigation channel detector cor DI and the subdivision device 15, so that it receives the pulses from the investigation channel detector D1 after they have been amplified by the amplifier ü1 and shaped by the pulse shaping circuit to1 as well as the pulses emitted by the dividing device 15 are supplied, i.-it the G-auter 16 is a pulse counter 1? ' connected, the e-zäbler ... ^ ebiiis indicating for -untersuchende to x-robe 11 oolcJie ImpulsZluiler are bekamt in mid ._andel ^ERBL:.. .I "Glich; uormalerv / iron number tubes are provided for iimen, so that a direct reading of the i..e..ztljii result can be obtained

Ji "si it in the selector 17 a" Jssamtzi. ^ Isr ^ ebnis gesaic-:;:; ._. T -7ei ⁱ den "'-: ri" -ji, the with .. ^ iIfe des erfi ;: Idun ^ sgerüien • 'i-oräts physical .λχ -euscNjrt of the examined i-robe 11 indicates, control the''devices for the jjrniiTtelii des \ ^ ·; ^ :.' ixtnis zv; i see the oigii & xen des err; öc-ii and second iietcictors D1 and "i)? _ the jurisdiction of the oil ¹ Xi ^ Is of the"investig-jnt-; skanaxdeteattors DI j "i a predetermined V'e.oh: · .- tnis to the fax-. ^ ,. al des ^ elh, öivanalaetektors ij ^ o This ote: jcrnjjg vyix'd durc ... i ax onti rti-ixuii; _: svor3? ichtun-i; ■ χ ·> and d jr:.-Jcvutcr Ib so bev / irict, öüic d ^ s o. "., Aial dee errs ten i / e Debtors xi'i , .- m · ^ ajer 1 / to.; Ef αηζ · υ - "ira, ... ίΐ other words, o.:jr, j-ii-'c. u: .se :: 7OiJ j-GipUj. :, _: 'eiiieii Vv; i" i oem JJetek'f, or DI ■ im ueu'i υ ··. '!:. ■■ L (Ί-ιχνν 'tuü'Ci-, ί; β ^ voor 1 ..- mrbfC dem a

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■ den'Ji ^- XL XiUj-J of untertellun ^ Gvorrlc / itunir 15 allows, at this ^ ~: ec "- 'lcs.r-.n ^{^;} s xctbcr 16 as el ^ rtrcri-'sö .he; u- ^ ~ - ter trained ssin.,. des -Jt! 'esuteorper- or lielaissc aJ.ter or other suitable .ocnaltun ^ selemeuce umi'-j-bt, which were eirund, turned off v-ürmea, um αε.ε Letting elites control Strons, ύ ed err. I ^H r.chr.ann. In the field d?: - r eleictronischen oc ". ε.1ΐυ.: ι .er. are other similar ochalturi-3'Gelei ^ duck known ^ ez '- ^. l -'- C ¹ .:. äes ^ usamraenarbeitens der uiitev-teilun .'- G-vorricV-tucg x.;, des matters 16 and. of the counter 17. k'f. '.: it has now been determined that the v / & hl of the .j. drawing "üntteiluLii ^ svcrric-f.tu-Uii-" for the lünpulsanimlex · dom the impulses des jöezu ^ i'arLals supplied xverden, to the fact that the -jat'oer 16 is actuated with a number of impulses so that the number of the move s channel detect or χ-'2 also incoming impulses by a previous ^ ·. stinrrüe ^ ar.I divides n ^r ird. ^ .i'C other .orten, v; enr ± the ünter /crricL'Cur.{V before Inbetriebnanme the number cuf 2 ^ 0 Uuo a £ ^ s "ueiit \ vorden" ceilu _J ^ s! ". a pulse is fed to the matter 16 when the first _rupuis of 250,000 Icvoulsen emanating from the Bczu ^ cl-ianaläe ^ ekOcr D2 reaches the unti-rtcilun -; - svorrichtuüc: 15. -; achdGH of the gate 16 such a pulse from the ~ ntr.rteilun ^ s device 15 otis su; of'ihrt has been, 'oe._ ir _. :: ^- c das -j-attsr 16, Irapuise durc ^.: "· allow that of the wiii ^ rs ^ c'.un "·.? - or iv'.ei;: fcanaldeteirbor ύΛ go out," so la.l the ^ e -.tu: ■; · -! .- e -to the voter 17 casual. t.enn then the le ~ s. ε of the 250 υυο impulses from the ^ ezur -'.- skanaldo'ceictor D2 arrives at the iitorteiungsvorricrLTiung 1 ~, the gate 16 is blocked, so that no further / iinpu-j.se

? 'kanäldeiieietor ke ^' from the "very -D1 Kings -gelangen to the / Javier. 1: ia _o G-'emfL; the ^ riladung thing is-.gedacht, constitutes 'the JN' ter'ceilungsvorr-iciicung 15 can be set so that "it controls the Leitiäiji :: - χΐΐ of the '- subordinate 16 in each case according to' one of several selectable x'eilern, the ζ. δ. - 5ου Üüü or 1 0Ou 000. 'pulses can correspond. .'..- '

ijezüglich the vrirlaui; jweise of the above-described invent.unr; ö _; -.; - ni'L-en device it can be seen that the üntersuciuui.'skanalprobe 11 and the xiesur ecaiialprobe 12 - '. through the

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source 10 are irradiated with an ionizing radiation ο The changes - the ionizing radiation through the two robes 11 and 12, which indicate the properties of the troubles, are detected independently of one another with the help of detectors 1) 1 and D2. With regard to the reference channel detector 132, it should be noted that the change in the ionizing radiation caused by the target sample indicates a property of this sample which is known to be stable, while with regard to the flow channel detector DI it can be established that the change in the ionizing radiation caused by the Measurement channel sample 11 indicates an unknown property of the material to be examined, with the help of the subdivision device 15 and the u-atters 16, to which the pulses emanating from the detectors D1 and D2 are supplied, which are amplified and amplified by the respective amplifiers A1 and A2 The counter becomes 1 '/ as a display device depending on the detection of the change in the radiation through the ι robe to be examined according to the detection of the change in the radiation through the .öezugsprobe controlled so that a di-. ü'e.'ter comparison between the change in radiation by the irradiation 11 and the irradiation 12 is carried out in order to indicate the previously unknown properties of the material of the robe to be examined, the ionizing radiation of the common radiation source is transmitted to the l to be examined - The sample and the reference sample are preferably supplied at the same time to ensure that the statistical deviations with regard to the effect on the material correspond to the same total statistical value as far as possible. Each of them carries out the recording of the planar radiation changed by the source 10 or the probe 11 to be examined and the corresponding detectors D1 and D2 at the same time is ensured by the use of the dividing device 1 ¹ J> and the gate 16, which both the reference total count and the Iiess total count within the same here

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• Also known as the common upper range is supplied ..

In order to make the importance of this work emerge even more clearly within the same period of time, it should now be expedient to go into the method by means of which the measuring device according to the invention is calibrated. By previously setting the setting point of the dividing device 15 to a selected number of ZoBo 25,000 this will be. rSezugsgesaintzählergebnis "defined This is done in such a way that one selects the material of the ne zugskanalprobe 12 and the geometric relationships of the radiation source 10, the Abschirmunssmaterials 13" of the reference channel sample 12.and of the associated reference channel detector D2 determined üomit is esamtmeßzählergebt G the device according to the It is calibrated, which is collected in the selector 17 during the time that is required to collect a reference total of 250,000 in the dividing device 15, since these two total counts are within the same period of time or * of a common upper range, and since the greatest possible commonality of the circuit elements and the sources between the verses Al, A2 and the pulse shaping circuits Pö1 and PS2 is present, the effects of the drift on the reference are the same - Total counting result and the ikeß total counting result automatically. The device is calibrated by establishing a direct relationship between the total measurement count collected in counter 17 and the physical property to be determined,

Included in a certain operable embodiment of the apparatus of the invention thus far described the device for supporting a untei'suchun.gs- ■ kanalpro.be taken from a material with an unknown property and a .Reference channel sample made from the .material, from which Properties are known for irradiation with that of

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The source 10 emitted ionizing radiation according to 3i'i: .-, o 2 a sdaranlcalialich.es G-ehäus 20, which generally has the shape of a rectangular ^ uader "The otra} .iltm. {: Gquelle 10 is in the housing v; e sent lent en its center, and the va-e house is divided into two "_c? niBers, of which one is arranged above and the other below the radiation source. ^ den von- der ocr-eh-lun ^ s source abpce-Y;?. ndten '.vands of itami: cni -the detectors D1 and D2 are attached, iiiue of the two ivamiaerh of the u-ehäuses contains the jszu. *, sprobe 12, which is in an unchangeable position - between the idtranlun.i; ε source 10 and the associated detector D2 is arranged, v / ühre-id. the other chamber when u use the u-device üoivi: '. as prove daroV. one in oc. ·. arnieren stored ± ^v ar 21 eGcLxoase: ·. is. u ^.; .e rrcben des i-ateria ± s, whose physi; alisc'je Otiarakttristilc eo.iaitr-elt -.verden, can; .about aie x'Jr-i '; uiUii ..- ! ■: .. :; ie 3; -oi't; e ώ-aimier are introduced, and f'i-e -sir remains v / '-' / hrc-nc. äer - .. e.v period closed

in iiahr_-rii the ir:? i: i: amc ± <rc: also it .cedac. '.'u;, daii d - '. s v-.i.'ic'- reu z'oiu u- ev.ar.j. '. ^ 2i riues 7 :: r ": artri £ ses zv.'isc-ien cot- ..e' ^ sähl - :? 3eb: iiß. and a ..--. zu ssä -iler ^ e?: -. is in; ::. srhalb an e: reir- ~ ^ "" on real äei capa'ine auc'i toi dtrahlui. ^ s-! ■ •; e -: - _v ; c : '. "-' Jten? .- .;] -; '. ::' den l ^: 'iot, the ivi ftri ^ en on known., Eise i, U3-; e''lldet s nd. ^ N ßonc. from jj'I'o ο 'oils ■> v / earth in the following - .ccijU -.- te ■ x-onetriscl-e arrangements for itn? / endun _: _: der jJrii; inu: iu: -ridm-erti in i'ij. ·. "^ To V are different Ub ^ ^rfl: Chen UNOE li- ^ ^ enßieß crHte dcr ^ csuellt In, each '' all in nrscheiaou EICI the J ^ ^ a rgestellG surface- and uJiefenne -.! -,"" .cr ^?; te from the vorste / .end an _ .. i. \ nd from i'ig. 1 and 2 besc. '' riebe.ue: i o-crätcn.; rounds ".tziich äadurc._i, that Another rjeoinetrisc '' - e ^ - ^ rlnuü - the ot-rabl'xi; scUGlle Iu, des! "eJJ-kanaio.r; tektors D1 and the ^ ezu _l :; -j .-: a: aaldetektors D2_ provided is, as well as the fact that the material to be examined no l ^v robe eritiioro ^r cn lu v / er de η bra: eight ₀ For this- α-round the Jiesu'T seich en "ur is.ennzeicmiun; c'irsr- r and further parts of the preliminary rite · eüü. besc.riobeijen-'i '^ rüto in i'ig ο 3 to 9 also to Ji e ζ c; iol j nun ·, ■ _ dishonor cL ender'l'e'ilr- der da v ^ c shared u-harvest

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eiii \ t-been set "under -3er". ^; ck8ic-'ti; -: unn; of the already known user-s'veine .which surface and ^ icfsnmeßrgeräte include the here _d. & 4 ^ 5-es-tFel "i '* - ea-ts - * ^ utc each a J-Gfciluse for the transducer: d: r _; jt:? &. J un / sr.ucile IU and the detectors ^ DI '"" and D2, between these KL a ten noc ^; "the associated electronic oc'-ßitunv- is provided, the the amplifier AT bsv /, -j.2 and the discriminator i ^j o1 or tö2 loosens, and. furthermore, each measuring device comprises the display device selected in each case and electrically connected to the device by a cable. In more active cases it can be useful; all named parts are to be housed in a common housing. Such a- ^ incrdnun ^ is usually chosen in order to facilitate the use of: ■ devices in the field ..

The in i'ig. ί until? D & .rgest.ellter 'r ^ eometrirjcLen arrangements apply s ^ .rr.Triich for Uberf j.ochenmeßger - ite, in which the change of the ionizing radiation; hftranf ^j; eso: '; s ■■ "ird to the physical oiiigensc /' aften or Ghtrakteristiken the katerialien to untevsuc.::eaden on the surface thereof to determine ^s 3EI the iC.ordnun'i'en according i'ir. > 4, 5 ujid ■: v: ird a ^ ezu-skanal sample 1 "from a La-üerial verv; ends, άε, δ eir.e known Oharakbcristik e.ufv / eist« isei den in χ · ¹ : ".. ". ·: And 7 devices shown: L :: c der oOrahiunrgsnuelle Iu _{ 'jev; e_- ε eii.i- shielding zu'; ecrdneu, which also serves to prevent the. the otra.J-un.Gsquelle to bundle emitted otstrahlun ^. ... with other ./locations which - / on the source 10 otranlung rirc. tl from the source cus i [ 'a i' s of a predetermined line: - '■' .s: rc ... ji; o remains the ueli channel detector D1 addition tRIT a ¹ collimator y ^ rseneii, aer the field of view of the detector to a gew.-i.iu.te i'l ^.: c''se below dei? about curse des ^ u unoirsuchende :: luateriels!: e _t <renzo, that in if'iy «4 to 7 as --re. dashed, - ■ «?,: eichnt; tes xtecbteck shown ir; t and the ... e-JTlcanalnro'be 11 -biiaot. xOihe such -Arbcitswej se, at aer the i..eßkaüalr.; .- obe ix - .r, a costinimable fiefe untex · aer ji'j ^.: "che liC: Vt, m-ü 'c. he who rests the device is from the Anordiiuij -en. -I ' ¹ .'...--. ¹ I and. 5 - "u untci'sclieiden, where the, .. ej.'küJiaxproi- ¹ : ·;" i j. the ιΊ; clie are adjacent to the JeT ¹ M- -. 'ri'ß't, r; .i -A). inoci- TfiudeFteiis über (\ r eire bestämmte

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btreclre extend down into the material.

The device shown in U ¹ Ig ₀ 7 differs from the other devices shown by a further feature. To be more precise, the tensile sample 12 used in the device according to Fig. 7 is formed by a volume within the i ^ atexial , on the surface of which the device rests, and which lies at the intersection between the bundled radiation emitted by the source 10 and the limited field of view of the .tsezugskanaldetektors 1) 2. With a device of this special type, not only is compensation achieved with regard to the electronic drift and statistical critical points in the measuring system working with nuclear energy, but the effects of the local chemical composition of the material to be examined are also compensated. In the device according to E ¹ Ig ₀ 7, the reference channel sample 12 is a material that is not fully characterized during the time the measurement is carried out _, nevertheless compensation takes place in the case of the flow results obtained with the aid of such a device with regard to the electronic drift and the statistical factors, so that this arrangement in the alxge! my scope of the invention fell '

If the invention is to be applied to density measuring devices in which the direct transmission of ionizing radiation takes place through a material sample in order to determine a physical property or characteristic of the material, a geometric arrangement of the in i'i &. 8 and 9, the flow channel detector D1 is arranged in such a way that it detects radiation from the source 1.0. which has completely penetrated the measuring channel sample 11 * In the embodiment shown here, the measuring channel detector D1 is arranged on our .rinde of a probe, which the device Ob ei? | ^ äch.e ^h 4e s « W , Wait ^ r suöhe & (ie $ fe> Mate £ $ & $ β from \ - -Ά

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Although various modifications of the in Pig. 1 described schematically illustrated parts of the device, but it should again be noted that the invention is intended to apply the method described to others as well to adapt the geometrical arrangements of the parts of the device, taking advantage of the automatic compensation for electronic drift and statistical factors remain,,.

Although the above description relates in particular to the use of devices in which the display device 14 is equipped with a counter 17 so that the measured values are obtained in numerical format, the invention also provides for suitable measures to be taken can be to achieve a direct output of measured values, a continuous printout of the measurement results or the like, for example, with the aid of a speedometer or a recorder. For this special purpose, the display device 14 enclosed in a dashed pike-corner in FIG. 1 can be replaced by the display device 24 shown schematically in FIG to operate an I & Eß device with a direct display or an emergency tire registration device. In order to generate such an analog output signal, according to B ¹ Ig ₀ lü, one see and a second Mgital-to-analog conversion circuit ;; - 25 and. 26 are provided, which are operationally connected to the associated amplifiers and pulse shaping circuits of the measuring channel or the draw channel, the ociialtungen 25 and 26 can be formed in any suitable way in ϊΌχτη of G-eachfrequenzsmeßschaltungen-to which one dux-ch the detectors -iDi- and B2 generated, amplified by the respective amplifiers Ai and A2 and by the iMvehöxi -en

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Claims (1)

Patent approval -1 * Procedure for examining a material with regard to the presence and size of certain characteristics which cause a detectable change in ionizing radiation ₅ in which a sample of the material to be examined and a suction sample of a material from which it is known that it has the relevant characteristic, is exposed to ionizing radiation of a type which is changed in a detectable manner by the specific characteristic, and in which the radiation changed by the materials of the sample to be examined and the target sample λ ^ οη an examination channel detector I) Sw _{1 is received} a Besugskanaldetektor and by comparing the signals the specific characteristic of the sample to be examined is determined, thereby gek e η η ζ e 'i η et that the irradiation' of the to be examined The test and the test sample at the same time ensure that the examination channel detector and the reference channel detector d ie, each time changed radiation is received at the same time, and that the reaction of the sub-scanning channel detector to the radiation from the material of the sample to be examined with the simultaneous reaction of the reference channel detector to the radiation from the material from the P ο mag spro "be thereby It is compared that the reaction br, -.- "dan ßi.aial des testun ^ ßkanaldetektoi-s in jt the reaction or -" your signal of the BeaugskanaldetektorG in the ratio nt v; ird. 2 .. Voriahrei), 1 ei that of the Investigation Channel Donor and the BcM ^; , ugi3] 'ai] a.hicii] -. t (i] - as a function of ^ oπ of the penetrating radiation liiiDUl r: vpi lien aunnendon, according to claim 1, thereby κ; π - BAD OB) GINAL from
indicates that the pulses emanating from / the examination channel detector are allowed to pass in a predetermined ratio to the pulses emanating from the reference channel detector. 3. Method according to claim 1 or 2, characterized in that the number of pulses is determined which emanate from the examination channel detector during the period, during which a predetermined number of pulses has emanated from the reference channel detector. 4. Method according to claim 1, characterized in that the pulses emitted by the two detectors are converted into analog signals and the analog signal of the examination channel detector is set in relation to the analog signal of the reference channel detector. 5. The method according to any one of claims 1 to 4, characterized in that the two samples are simultaneously and independently exposed to radiation from a common source for ionizing radiation of the selected type. 6. The method according to any one of claims 1 to 4, characterized characterized in that the two samples are carried out simultaneously and independently exposed to radiation from multiple sources of ionizing radiation of one species. /. Method according to one of Claims 1 to 6, characterized marked that for evidence of changes the ionizing radiation through the samples the ionizing radiation from 009 8-2 6 / U6Ö & AD OBiGINAt .the .otstrahlurigsquelle from in predetermined - ^ onen initiated , so "that it enters the jr rob s, and that the detectors shielded against undesired scattered radiation, which could otherwise lead to inaccuracies. 80 Method according to one of the -ansvr-lives 1 to 7 »in particular for" iilrmittlurr, des hydrogen .enaj-ts "? Incr .frobe, characterized in that the irrigation is exposed to the radiation of a source of fast ifeutron radiation, and .that the detectors respond to thermal neutrons, the infox. ^ e of the moderation -of the fast neutron radiation by the hydrogen content ψ of the material of the examination channel sample and the jiezu-jsl: anal sample are generated, y. Method according to one of Claims 1 to 7, in particular for determining the density of a sample, characterized in that the samples are exposed to gamma radiation and that the detectors respond to photons which are dispersed by the materials of the examination channel sample and the jiezugskanalprobe . lüo method according to one of. Claims 1 to ',', in particular to determine the density of a sample., characterized in that the samples of a uciruüasbrahlung and that the detectors are responsive to photons transmitted through the materials of the test sample and the duct sample will not be scattered ». , ILo G device, in particular for carrying out a procedure according to one of claims 1 to 10, with an öbrahliuv.squelle, the one chosen kind of an 'ionizing üx'ahluriu; which is known to have been caused by a certain Characteristic to be measured changed in a verifiable way as well as with detectors including a survey. : skanaldetektors and a BeKugakanaldetektora, from O O Ο 8 2 6 / U 5 Ö jmmm a & a ^ _{0 0RIQINAL} each generating signals in response to the change in the radiation emitted by the radiation source signals anaeigen- the presence and size of the specific characteristic, characterized geke η η ζ e Lehn et that the radiation source (10) and the Betektoren (Bt ₉ 1) 2) are supported in a predetermined geometric relationship to the investigation ": n {" S-channel sample (11 ') and the mountain channel sample (12), so that the investigation "channel detector" (131) the The radiation source emitted by the radiation source and received radiation changed by the specific characteristics of the test sample, while the suction channel detector (1) 2) receives the radiation applied by the radiation source and changed by the specific characteristics of the suction channel robe, and that a ratio sbil (nni: ^T , rvorr-j crjtung (15 _s 16) "for the formation of the quotient from no, Jirnal the investigation channel detector and the signal of the le ^ u ^ okanaldetector and one of this sugeo appropriate quotient adjustment (17) are provided " 12. Apparatus according to claim 11, characterized in that it η η ζ eic h ■ η et. 'that the extension of the radiation by the. skanajprobe untersuclmn ^ and by the BerAigskanal-probe gleic.üsei ^J) r detectable, so da'- ·· -which is furnished by sneezing change hervoj-rrrui'r-NEN Signa 11 e within the same Meßseitspanne the OE ea'-ut ; ⁷ · on t, j'o I. en. 1 ^v . Device. · Nacb Anspmicb 12, thereby ε el ·, e η η ν; e i. ch - bar not «that (Ji.iT- samples (11, 12) irradiated equally and uin Vηi \ ^? ii'ui (v-'uHi ^5- r.ii ti <v radiation through the samples, rleiobneitiä after-Vi ( ¹ UiJbUr are, ivi. D'iss the]? Irradiation and the Hachvreis iunerhaJ ii de. * R-lc · ■] (.'hen 1 (• ■ tri.ebsF.eidiSpan of the device. 1 / y. Device u'icb. one of claims 11 to 13 ₅ β cke η- η - · /, C-- i ■■■ h η (- l. Through pinen digital S'amiiiKr (1S) ₅ dor the from one of the 1 ' ⁵ · 1.π] :. ΐ (.Γοη (1) 2) auscosauaten impulse srcn.hnu emjjCiiu /' ί. and eitie "';Ί,' η tJTnml-e ZaViT. this Ti'tfjul ß! - sauiriolt, f; iii iii _: " iia.l pa \ .u-. \ - ('' b), that there? '. By. l.aaG'.fn der van fi-.m other tui \ ', t- \ < κ i -ijp (1i1) nu ·· .; r.'ii ··· πα inn Imjiu ί i ": rc i.beii ο ο β o; -: 6 / u B i \ ; _{& v} ., r _; y _: -. SAD QRiG (NAL in ^ bhrn ^ i ^ is of the controlling & u-: ll.nk ics u £ -rJ.crs controls, some an airritalen ^ iihlf.r ..17)? the dio of the: oi / "na.L -etter durc-r '.-'C-assener; In '.: aj.se- der du.rc ■ den ancors-r.- · juexie"' tor (. 1/1 j produced inr> in. Sreii'en ecpf-h :. t and 15 · Cler ^:: t iiac!:. one- the .aus- :: ¹ · ¹ before II υΐε 1; -, e - ke η 11 ζ eic Ii η ct by a first and a second Mgitc \ l-iüialog converter (25 »26), which the xieiLcn emanating from the detectors (D1-., D2) from oi ^ 'iaiim ^ ulcGn in ansio ^ e 'jeschv / i ::. 5.i ^' eitGsigna. '. e (rate ei.,. λ · :; Is) umv. ^r rräeln, as well as through an analog subdivision ^ svcrrichtuii} ;; () 16o- ieri-'t npc'i one of the iinsprüc: g 11 ris 13, 1.:.?: '<: 1 - none ere zurr; - ,. ess6z. .ein ^ r Gterf l ^ chenchcraktcristik, _; eke η η ζ eich: ier durci ein oauteii srsit ei. "_ '. r .s-.ll- _{: i} -e ^ e.in. flat underside, the "Ate:? Jal and in intimate _) ': r'ii:, run ;; deenit ebs "u ^: tzen, the btrahluii.jsquelie (Il-O and the uiit: rruMimcßlcanaldetelctor - _V D1) 5ege.nj.above this,.-j-.uteii so ; .. c, -corded, da . .S the au examined i did _';: -:' ial irradiated -: ■ rd, and that the change in 'the btra] .. development demonstrated by the i-ateriai dadurc, r / irc · dal: the. otstrahlun-r through the jLauteil ".icsrtr: .. ren ui: 4 cjurc" the I-ateridl to be subdivided reflects v / irä ο Ι? Ο G-ert.t according to one of claims 11 to 13, in particular for the better e-iK-: r iJichtecJiaralcteri-stik, r; eke η η draw du.2? cii one in the su investigating j, .material eir: füjjrbare oor.de, which either the dtrahlun; '; cquelle (lü) or the üntcrsuc-iun.-jskanaldetci.tor ^ JD'l ) deceptive, where the i3traljlun; _ ;. '3oue.ile and the LIntersuchun; jskanaldetektor are arranged so that the examination mn ._, scanalprobe (11) between the oi.rcjj.lun ^ source and the examination. i;] t: anal detector bei'iunet, so dal: the absorption of the ütrahiun ^ nachrrevv'ioseji are kaini, nordem the ütrahlun-, · o.ie investigation Uii skaijfi I] ¹ In. 1. e uurchdrun -en has ₀ 009826 / U58 SAO ORIGINAL Blank page