DE2354354A1 - THE DETECTION OF NEUTRONS AND THE RECORDING OF NEUTRON IMAGES - Google Patents

Description

AGPA-GEVAEET AKTIENGESELLSCHAFT LEYERKUSM

Detection of neutrons and recording of neutron images.

Priority: United States of America, November 1972 Note no. 303 387

This invention relates to the detection of neutrons that Recording of neutron images and on the use of special substances, materials and apparatus for this proof and this record.

The interest in neutron recording and neutron detection includes neutron dosimetry, neutron deflection, Neutron radiography and neutron image conversion into a visible one Image,. e.g. in an image intensifier tube »Neutron radiography is a well known and valuable addition to X-ray and gamma-ray radiography.

As is known, for example, from H. Kalimann, Research 1_, (1 ° A8), No. 6, pages 254--260, neutrons essentially _{do not attack a p (} photo-sensitive silver halide Combination of silver halide film with a neutron sensitive intensifying screen applied.

In general, fluorescent screens that are sensitive to neutron radiation can be divided into three classes according to the function they have to fulfill.

The first class contains screens, here called "neutron conversion screens" to be named. Such screens have the property of being in a fluorescent screen with photons from UV radiation or from

■ 409820/0296

generate visible light, whereby the screen is in contact with a Has photocathode, which emits photoelectrons under the influence of fluorescent light. Such screens can be used in image intensifier or image conversion tubes similar to those known from X-ray radiography are used are (G.J. Van der Plaats, Medical X-ray-technique (1959) Philips'Technische Bibliotheek, pp. 103-108). The photoelectrons emitted by the photocathode are in such tubes Electrically accelerated in a vacuum and an electric or magnetic focus field is used to create the electron image set to another eluorescent screen that is sensitive to fast electrons. The photoelectrons are thus converted into visible light in a manner similar to that known from television picture tubes.

The second class includes screens, which here are "fluorescopic Umbrellas "are called. Such umbrellas have the function of a directly viewable image in accordance with the neutron image to create. The screen is viewed, for example, by optical means, or for the purposes of cinematic radiography, or photographed to produce television images. The fluorescopic Image can with an electronic image intensifier tube. amplified before it is viewed or pliotographed.

The third class includes screens, which are referred to here as intensifying screens. Such screens have the puncture to convert the neutron radiation into electromagnetic radiation or high-energy particle radiation, for example ß- or Α-rays, for which a photographic s material that is in direct contact with the screen is sensitive.

Usually the intensifying screens are used in combination with silver halide emulsion film sheets which together and are mounted in direct contact with the screen or screens in a light-tight cassette.

There are two express imaging techniques. In the one who "Direct exposure method", the phot ο graphic egg and

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the screen, in which the neutron energy is converted into energy "to which the photographic I ¹ Hm is sensitive, exposed together with the neutron beam to be detected or recorded, while in the other method, the" conversion method ", only one screen with the Neutron bombardment gives the screen a radioactive pattern that corresponds to the neutron beam pattern. This radioactive film is brought closer to the photographic film. The film is then exposed to the decomposition radiation of the screen (Nucleonics, 20 (September 1962 ), No. 9, page 77)

There are three basic types of intensifying screens used in the thermal neutron radiography can be used, viz granular screens, as well as glass and metal foil screens. M.R. Hawkesworth et al. Describes in J. Scient.Instr. 3 (November 1970), No. 11, pages 851-854, as a granular intensifying screen Screen, which is a 1: 2: 1 weight mixture of lithium-6-fluoride, Contains zinc sulfide and polymethyl methacrylate binders and one Has a thickness of 0.65 mm, as a metal screen a 25 jam-thick Gadolinium foil and a plate of lithium-6-oxide-charged, cer-activated scintillation glass 1.3 mm thick.

The metal foil screens must be set to two types, namely, metal screens for "direct exposure" and metal screens for transfer exposure.

The most suitable metal screen for direct lighting is the Gadolinium screen, which has a very high thermal neutron absorption, the ones with the immediate charisma are less energetic (70 keV) / 3-particles coupled. The screen therefore has an extraordinarily high resolution. The 70 keV electrons carry only 1/68 of the energy of the neutron reaction Li (n, oi) T, that in the above-mentioned, granular lithium-6-fluoride-zinc sulfide screen takes place. The basic reaction in

6 3

such a screen is ^ Li + η: ■ - > ^ T + <*. + 4.79 MeV. if

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the rather low activity of the gadolinium screens in The most sensitive silver halide films must be used in conjunction with this. The gadolinium umbrellas are insufficiently selective to detect neutrons in the presence of X-rays. Hence the metal foil screens Used in transmission technology to achieve a perfect To give differentiation (shielding) against y-rays. Other ways to exclude ^ f radiation from the nuclear reactor will be im J.Phot.Sei. Volume 19, 1971, page 108.

In contrast to gadolinium, most metals emit / 3-particles some time after the neutron absorption. When a Foil of such a metal is exposed to a neutron beam behind an object, becomes the radiographic neutron image stored in the foil and then removed from the beam and pressed against a suitable photographic film. the Radiography is then produced when the slide is active dwindles. The metals most commonly used for this activity are dysprosium and indium. The transmission technology requires more time than the direct exposure technique.

The present invention is a neutron detection and drawing technology, in which fluorescent substances that are particularly sensitive to neutrons are used. Another The present invention is a combination of photographic materials and such fluorescent substances, which are particularly suitable for neutron detection and neutron recording.

It has now been found that gadolinium compounds, which have the property of fluorescing when struck by X-rays, have a very effective neutron retardancy and have the property of converting captured neutron radiation very effectively into visible or almost visible radiation to which the silver halide is inherently sensitive is - or can be made sensitive by spectral sensitization.
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A method of recording neutron images or the Contains detection of neutrons according to the present invention the following steps: (1) Neutron irradiation of a reinforcement screen, which fluoresces when X-rays strike Contains gadolinium compound, and (2) projecting Fluorescent light resulting from the impact of neutrons on the screen on a photographic material or the Detecting fluorescent light with the human eye or with a photo-sensitive, electronic light detector.

Suitable photosensitive electronic light detectors are e.g. semiconductor photocells, photoconductors or photoresistors and any electronic device having a fluorescent light sensitive photocathode as a photosensitive member having.

The gadolinium compounds used according to the present invention have, as one can learn from comparative tests, a much larger "relative amplification factor" than intensifying screens made of pure gadolinium.

"Relative gain factor" is understood here to mean a factor measured at a preselected density D, which indicates the dose required to generate this density (neutrons procm2) when a silver halide film with neutrons with a "Standard screen" is exposed divided by the amount required to obtain the same "density" with that to be examined Generate screen. Exposure, film and development conditions are kept constant for the comparison tests.

According to the invention it has been found that gadolinium compounds of the oxide, oxyhalide and oxysulfide types are particularly valuable Means for detecting and recording neutron beams are. Preferred substances when using the one according to the invention Processes contain gadolinium as the "guest" metal preferably to at least "70 atomic weight percent of the other metals in a phosphor / or self-luminous " substance are contained in which one or more other rare

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earth metals are present as fluorescence-activating metals.

Visible light emitting, neutron detecting screens used in accordance with the present invention are preferably fluorescent gadolinium oxysulfide or oxyhalide, those with at least one other selected rare earth metal, e.g. terbium, dysprosium, erbium, europium, holmium, Neodymium, praseodymium, samarium, thulium or ytterbium are activated.

Particularly suitable self-luminous substances for use in neutron radiography correspond to the following general Formula:

Gd / .MOX
(wn) η w

in which:

M at least one of the rare earth metals dysprosium, erbium, Europium, holmium, ueodymium, praseodymium, samarium, terbium, thulium and ytterbium,

X sulfur or halogen, e.g. chlorine, bromine or fluorine, η the numbers between 0.0002 and 0.2, and w 1 when X is halogen, or 2 when X is sulfur.

The preparation of Seltenerdoxyhalogeniden and Oxidleuchtstoffen has been and described in the I ¹ R-PS 2,021,398 of JG Rabatin in U.S. Patent No. 3,607,770, for example.

Gadolinium oxyhalides activated with dysprosium are described in particular in Canadian Patent 916,915, and gadolinium oxyhalides activated with terbium in US Pat. No. 3,617,74-3} gadolinium oxybromide activated with erbium in US Pat U.S. Patent 3,415,757 .

Gadolinium oxysulfide activated with other rare earth elements is disclosed in U.S. Patent 3,418,246 and S.P. Wang et al., IEEE Transactions on Nuclear Science, Volume NS-17 (February 1970), pp 49-56, and by R.A. Buchanan, IEEE Transations on Nuclear Beien; *.,

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February 1972, pages 81-83 ".

Fluorescent gadolinium compounds which can be used according to the present invention are mentioned in the following patent literature: in GB-PS 1 018 005, 1 022 930, 1 110 290, 1 122 923, 1 '128 512,1 13I 956, 1 247,602, 1,248,299, 1,249,544, 1,254,271, 1,257,322, 1,263,038, 1,266,407, 1,269,329, 1,279,450, 1,284,296, in U.S. Patent 3,282,856,3 301 791, 5 415 757 ', 3 418 246, 3 418 247, 3 434 863, 3 484 381, 3 502 590, 3 546 128, 3 562 174, 3 563 909, 3 574-129, 3 31 ¹ ^ 131 , 3,634,282, and 3,661,791, in CA-PS 799 899 and 816 628, in (th DT-OS

1 222 610, 1 284 296, 1 592 884, 1 915 360, 1 935 103, 2 05I 240,

2 051 262, 2 108 676, and 2 201 27I, in NL-OS 66/3921 and in FE-PS 1 468 075, 1 501 441, T 504 341, 1 542 140, 1 550 113, 1 580 544, 2 021 398 and 2 039 921.

Gadolinium compounds that are in the UV and / or visible spectrum range are very suitable for neutron radiography with silver halide recording materials.

A neutron sensitive intensifying screen with high Sensitivity contains e.g. a terbium-activated gadolinium oxysulfide, which has emission peaks at 490 and 540 nm and in falls within the scope of the general formula mentioned above.

Although in the fluorescent screens for use in the Ueutron radiography according to the invention preferably only gadplinium-containing fluorescent compounds are used, those screens are not excluded that contain the fluorescent 'gadolinium compounds in a mixture with other fluorescent substances that are affected by the impact of X-rays and / or / or 3-rays fluoresce. For example, it contains a suitable fluorescent screen a mixture of 25:75% by weight of:

(A) yttrium oxysulfide, activated with 0.1 to 10% by weight! Terbium, or activated with terbium and dysprosium and

(B) gadolinium oxysulfide activated with terbium or dysprosium;

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it is because of its high emittance of visible light particularly suitable due to neutron irradiation.

A silver halide recording material to which visible light can be made optimally sensitive, e.g. for green light, emitted through the fluorescent gadolinium compound,

By using several fluorescent gadolinium compounds in several different screens or by using a fluorescent screen that is a mixture of different fluorescent Contains gadolinium compounds of the above general formula, one obtains a spread over the entire visible spectrum extensive fluorescence, so that this combination is particularly suitable for recordings with silver halide materials, which have been spectrally sensitized to light of the entire visible spectrum.

The selected fluorescent gadolinium compounds will be used in the form of a layer arranged on a carrier or in the form of a self-supporting layer or film.

Particularly suitable fluorescent layers or films have a thickness of preferably 10 to 300 μm and contain them Self-luminous compounds or phosphors, for example, dispersed in a binder or in the form of a vapor-deposited layer or a layer of sintered particles in the presence or absence of a vitreous material.

The binder that may be used is, for example, an organic high molecular weight polymer. Preferred binders are cellulose nitrate, ethyl cellulose, cellulose acetate, polyvinyl acetate, Polystyrene, polyvinyl butyral, polymethyl methacrylate and the like

The ratio of high molecular weight polymer to self-luminous material is generally between 5 and 15% by weight. One

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"preferred grain size of the fluorescent gadolinium compounds is 1 to 20 µm.

The surface of the layer of self-luminous material can be against Moisture and mechanical damage caused by a top layer of an organic high polymer in a thickness of 0.001 to 0.05 mm. Such a protective layer is e.g. a thin film of cellulose nitrate, cellulose acetate, polymethyl methacrylate and the like

Except for the fluorescent radiation, which is perpendicular to the silver halide layer hits, there is always a certain amount of scattered radiation in the fluorescent screen, which gives rise to Image blur gives. Image sharpness can be improved considerably by using a dye which absorbs fluorescent light, referred to herein as a "screen dye" in the fluorescent screen material e.g. in the fluorescent layer or in an adjacent layer e.g. an underlying antihalation layer or store a top layer. Because the obliquely incident radiation has a longer path in the screen material covered than the perpendicular incident radiation, it is absorbed by the fluorescent light absorbing screen dye in weakened to a greater extent. The term "screen dye" includes dyes, colored substances in molecularly disperse form, and pigments.

Scattered radiation emitted by the support of the fluorescent screen material is reflected, is mainly in one of the fluorescent layer and the screen dyes containing antihalation layer weakened »

The use of screen dyes in a topcoat on top of the fluorescent layer mainly reduces strength of the light emitted obliquely through the fluorescent layer.

A suitable screen dye for use in the fluorescent screens, those in the green range (500-600 nm) of the visible

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Spectrum is e.g. Neozapon Fire Red (CI.Solvent Red 1.19) i an azochromrhodamine complex. Other suitable umbrella colors are: CI. Solvent Red 8, 25, 30, 31, 32, 35, 71, 98, 99, 100, 102, 109, 110, 118, 124- and 130.

The screen dye need not be removed from the fluorescent screen material and therefore can be any dye or anything Be a pigment that absorbs in the emission spectrum of self-luminous substances. So a black substance like soot gives which is incorporated into the antihalation layer of the screen material, very satisfactory results.

The screen dyes are preferably used in the antihalation layer used in an amount of at least 0.5 mg per m2. However, its amount in the antihalation layer is not limited .

Very good results are obtained with the screen dyes in the antihalation layer and in the layer that

Candlestick contains substances. In this EaIl the Fluorescent layer e.g. the screen dye in an amount of 5 mg per m2. The amount of screen dye in the fluorescent layer and / or the cover layer can be adapted to the results of the image sharpness and the desired radiation intensity.

The present invention includes the use of a fluorescent Gadolinium compound-containing screens in neutron radiography in conjunction with any other neutron absorbing screen, e.g. of the metallic, glassy or cored type, e.g. the combination with gadolinium-dysprosium- or indium-metal, the latter two of which use the aforementioned transmission technology, for example be used. The invention likewise encompasses the use of fluorescent gadolinium compounds containing Fluorescent screens in connection with neutron radiography with any metal screen that is relatively GV.653

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high neutron absorption! hai;, for example an absorption which is at least as high as that of lAthxaM in order to remove a certain amount of diffuse neutron stralils and thereby improve the image sharpness. An analogous technique in which a sharpness-enhancing metal screen is combined with a fluorescent screen used in Eontgenradiographie, has been described in BE-PS 792,387.

Met all screens with high egg-ion absorption capacity can be made from the metals cadmium, gadolinium, europium and samarium or from their alloys xferden.

With the D. ¥ use of preferred neutron radiography Combinations are used besides the! "Luorescent screen a photosensitive element comprising a support and photosensitive silver halide. This silver halide can be applied in a single layer or in a doubly applied layer, i.e. in a material: the one silver halide emulsion layer in each case Side of a carrier owns. Suitable carriers are those with the properties of a rapid passage through an automatic Tendon liver working machine to allow. The carrier should therefore be moderately flexible, preferably transparent, but be able to ensure the dimensional accuracy and completeness of the various To secure coatings on it «Typical film carriers are cellulose nitrate, cellulose ester, polyvinyl acetal, polystyrene, Polyethylene terephthalate and the like. Carrier like Cards or paper coated with 4-olefin polymers especially with such polymers of <y-olefins, the two or contain more carbon atoms, such as polyethylene, polypropylene, Äthylenbutenmischpolymerisate and the like ... give good results.

For I ¹ Or countries of image sharpness the SiIberhalogenidemulsions recording material be incorporated in the dyes referred to below as "I'ilterfarbstoffe". They are preferably in the hydrophilic, colloid layer, e.g. between the silver halide

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genide emulsion layers or in the emulsion layers themselves incorporated. However, you can also use one or more adhesive layers, both antihalation layers of the carrier and can even be incorporated into the carrier, to which they give a blue appearance and preferably an absorption density that. 0.45 achieved in the wavelength range of 480-700 nm. The dyes however, preferably have such chemical and / or physical properties that they can be found in one of the processing baths removed or discolored.

According to a preferred embodiment of the present invention filter dyes are used that are in the wavelength range absorb from about 480 to 600 nm when fluorine screens are used, which are exposed to neutron irradiation Emit substantial green light (480-600 nm).

The amount of the filter dye is preferably in the range from 25 "to 1000 mg per m2; however, it can be according to the desired The result is equally small or large quantities be suitable.

Suitable pilter dyes, consisting of hydrophilic colloid layers can be removed are, for example, those in the following table listed.

Table 1

¹ * n " ^V C = 0 HO-c ' ^N N

Ii t ""

π CC C = C-CH = CH-C-C-CH ₇ .

3 ι ->

CH ₀

3, 3

I ι

N Ή

N C = O HO-C ^ N

H..C-Ä C = CH-CH = CH-C C-CH,

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3- SO ^ Efa

H _x CC-3

C = O
ι

• C = C - CH

NaO-C ^ T) ι π CH - C - C-CH

CH-, 3

N ^Ν

N \} 0 HO-C ^ ^Ν Ν

HOOC-C C = CH-CH = CH-C-C-COOH

COOH

COOH

C ^N C

\ S

. N

HO-C ^ ^N C = 0

H _x CH ₀ CN C = CH-CH = CH-C N-CH ₀ -CH _x 3 2 N ₀ , ■ λ ^ 2

Il

6th

■ ο

O = C C = O

HO-C

it ^w

HO-CH ₀ -CH ₀ -NO = CH-CH = CH-CH = CH-C 2 2 N ₀ ^ ^

il 0

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CH ₂ 1 3

ϊί

O = C IC- CCC = O

N ^H 5 ^C 2 V ₅

HO-C "^ C: (Ι ι

H ₁ -C ₀ -KC = CH-CH = CH-C

ft it

0 0

SO

N G = O

Il Ϊ

H _Z CC G =

COORa IaO-C Ii ι Ii '' C G-CH,

10. SOYSTa

SO ₅ ha

K C = O HO-C 1

Ii i il J!

HOOC-C C = CH-CH = CH-CH = CH-C G-COOH

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11.

HOOC

12. "Filter blue-green" ν- * inking units Höchst

With the radio graphic combination of neutron fluorescent screens and silver halide radiographic materials according to of the present invention can use the light-sensitive screens Silver halide material may be arranged separately, or they may be combined with the silver halide emulsion layer complete arrangement "so that on one and the same support both a silver halide emulsion layer and a neutron-sensitive fluorescent screen, are attached. Uniform luminosity silver halide emulsion materials for X-ray recordings are disclosed, for example, in U.S. Patent 2,887,379 has been described.

The emulsions can be spectrally sensitized by any of the known methods. They can be spectrally sensitized using common spectral sensitizing dyes used in silver halide emulsions, including cyanine dyes and merocyanine dyes as well as other dyes such as those described by F M. Harner in "The Cyanine Dyes and Related Compounds". Interscience Publishers (1964). These dyes are preferably used in an amount between 20 mg and 250 mg per mole of silver halide.

Suitable spectral sensitizing dyes for silver halide, genid, which are to be used in combination with fluorescent screens that emit light in the wavelength range of 4-80-600 nm are shown in Table 2 below for illustration.

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Table 2

1.

-S

Cy - ? -

KOOC-H ₀ CSC C = CC = S ² HI! !

Ν — NO = C - N ! ι

• CH ₃

<jK ₃

O = C-N-CH ₂ -CH = CH ₂

CN SH _x CC C = CH-CH = C-C

N-N, N

HH _? C CH

CH ₅ , ^ t ι e

⁰ H ₂ C CH

—O S C

Ii ι ·. ι

L C - GH = CH - CH = C, .C

N * V

CH ₂ -, ^^. -COOH

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6th

H ₀ C-S S-CH ₀

² I ι Γι ²

H ₀ C C-CH = CH-CH = C CH ₀

7 ·

= C-CH = C

(CH ₂ )

8th.

^ C - CH = CH - CH = C

J ⁺ ■ _ I

CH ₀ -CO-IT-SO ₀ -CH, 2 2 3

CH

Cl-Cl-

K-CH ₀ -CH ₀ -O-SO ₂ " ί 2 £ ί ^

C - CH = CH - CH

S-CH, C CH,

10.

, C-CH = CH-CH = C;

-Cl -Cl

11.

= CH - CH =

CH ₂ -CO-II-SO ₂ CH ₅ ^ ₂ H ₅

-CH,

-CH,

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Cl-Cl-

ν sr

C-CH = CH-CH = C "

-I -Cl

NC-

2 = 5

^ C-I! CH = CH - CH =

C "

IN

-CIi

C-CH-CH-CH-C

CH ₂
3

C-C

- CH = CH - CH =

Ii

= CH =

CH = C! O = C _x SI

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ο- -Α *

"^ C = CH - CH = CC = S _] jf O = CN (CH ₂ ) ^ _{O-SO 5} H.

18th

^ C = CH-CH = C * C = S

C ₂ H

CH ₂ -COOH

^19th

CH - CH = C 'C = S

O = CNC ₂ H

CH

JS ^ C = CH-CH = C 20. a 5 I.

U_N O = C

C ₂ H ₅

C = S

C ₂ H ₅

21

C = CH - CH =

H ₂ C-3

H,

Supersensitization in the green spectral range can be done with the following compounds 22 and 23 of Table 2 in the molar Get ratio 1s 2. -

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22nd

The silver halide in the emulsion layers can contain various amounts of silver chloride, silver iodide, silver bromide, silver chlorobromide, Contain silver bromoiodide and the like. However, if it does is applied, after exposure and processing it must be able to produce a negative silver image on it remains, i.e. in situ. Particularly good results are obtained with silver bromoiodide emulsion, in which the average Grain size of the silver broajodide crystals between about 0.1 and about 3 µm.

The image-forming silver halide emulsion can be chemically sensitized by any of the well-established methods. Man

the emulsions can be made with naturally active gelatin or with small amounts of sulfur-containing compounds such as allyl thiocyanate, Ally! Thiourea, sodium thiosulfate, etc. mature. The image-forming emulsion can also be sensitized with reducing agents, such as tin compounds according to GB-PS 789 823, polyamines, e.g. diethylenetriamine, and small amounts of compounds of precious metals such as gold, platinum, palladium, Iridium, ruthenium and rhodium, as described in Z.wiss-Phot, 46 (1951), 67-72 by R. Koslowsky. Typical representatives such noble metal compounds are ammonium chloropalladate, potassium chloroplatinate, potassium chloroaurate and potassium aurithiocyanate.

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Before or after mixing with the low-sensitivity emulsion Stabilizers and anti-fogging agents can be added to the silver halide emulsion, such as sulphine and selenic acid or their salts, aliphatic, aromatic or heterocyclic Mercapto compounds or disulfides, as for example in the DT-OS 2 100 622 described and claimed, preferably Sulfo or carboxyl groups, mercury compounds, as for example in BE-PS 524 121, 677 337, 707 386 and 709 195, and tetra-azaindene, as described by Birr in Z.wiss.Phot., 4 £ (1952), 2-58, such as the hydroxytetraazaindenemit the following general formula ϊ

- ■ OH

A ^ *

3 j ι ι 1

EG

in which IL and E ₂ each "represents a hydrogen atom, an alkyl, an aralkyl or an aryl group, and E represents a hydrogen atom, an alkyl, a carboxyl or an alkoxycarbonyl group. ■ _ such as 5-methyl-7-hydroxy-s-triazolo [] i; 5-aJ) yrimidine.

Other additives, e.g. hardening agents, such as formaldehyde, dialdehydes, hydroxyaldehydes, mueochloric and mucobromic acid, acrolein and glyoxal, mordants for anionic color couplers or dyes formed with their help, plasticizers and casting auxiliaries, e.g. saponin, salts of dialkysuccinic acid, sulfosuccinic acid, alkylsulfosuccinic acid, sodium sulfosuccinic acid x , Alkylaryl polyether sulfonic acids, carboxyalkylated polyethylene glycol ethers or esters according to IE-PS 1 537 417, such as IsO-C ₈ H ₁ 7-CgH ₄ - (OCH ₂ CH ₂ ) ₈ -OCH ₂ C001Ta, fluorinated surface-active substances, as they are, for example, in the DT-OS 1 942 665 and 1 950 121 and in BE-PS 742 680 are described, and inert particles such as silicon dioxide, glass, starch and polymethyl methacrylate particles can be in one or 'more of the hydrophilic colloid layers of the radiation-sensitive

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silver halide materials according to this invention be.

To accelerate the development, the exposed, photographic Material preferably developed in the presence of development accelerators either in the silver halide emulsion layer, may be contained in an adjacent layer or in the developer bath. They include alkylene oxide compounds of various types, such as condensation or polymerization products of alkylene oxides such as those described in U.S. Patents

1 970 578, 2 240 472, 2 423 54-9, 2 441 389, 2 531 832 and

2,533,990 and in GB-PS 920 637, 94-0 051, 94-5 340, 991 and 1,015,023. More development accelerators are onium and polyonium compounds, preferably ammonium, Phosphonium and sulfonium compounds such as trialkylsulfonium salts like dimethyl-n-nonyl-sulfonium-p-toluenesulfonate, Tetraalkylammonium salts such as dodecyltrimethylammonium-p-toluenesulfonate, Alky, pyridinium and alkylquinolinium salts such as 1-m-nitrobenzylquinolinium chloride and 1-dodecylpyridinium chloride, Bis-alkylenepyridinium salts such as ΪΓ, ΙΓ'-tetramethylene-bis-pyridinium chloride, quaternary ammonium and phosphonium polyoxyalkylene salts, especially polyoxyalkylene bispyridinium salts, examples of which can be found in US Pat. No. 2,944,900, etc.

The silver halide radio graphic materials of the present invention will be according to the radio graph.! see radiation preferably in one powerful surface developer developed. This is necessary to allow the development to proceed quickly. The strong one Development can be done by alkalizing the developer liquid (pH 9-12), through the use of high-energy developer substances or a combination of developer substances that are very energetic due to their superadditive effect.

Image density is used to save silver halide in the emulsion partially built up with dyes, e.g. by incorporating color couplers into the emulsions, at least at the moment of development with the oxidation products of aromatic, primary

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Developer substances containing amino groups, for example of the p-phenylenediamine type., give dyes which are in the visible Absorb part of the spectrum. ~

It is also known that a relatively high maximum density and a relatively high contrast can be obtained even with a low silver halide content per unit area, by creating a dye image "together with a silver image, as described e.g. in DT-OS 1 946 652 »

It is also known that fine-grained. Silver halide emulsions have a higher covering power than coarse-grained emulsions (P. Glafkides, Photographic Chemistry, Volume I (1958), pages 89-90)

In the present invention, the term "opacity" is understood to mean the reciprocal of the photographic equivalent of developed silver _7, ie the number of grams of silver per dm.2, divided by the maximum optical density of the image obtained.

Fine grain emulsions, however, have low photographic sensitivity -

The low sensitivity of these fine-grain emulsions with high hiding power, for example at least 50, and low silver halide content ", ie one _{that is equivalent to less than 80 mg silver / dm2 s,} for example 3" to 8 g silver per m2, can be reduced by using -Be compensated by fluorescent screens that contain fluorescent gadolinium compounds and have a particularly high gain factor.

When carrying out the color development will be in view of the further reduction in silver consumption, so-called two-equivalent couplers used, with 2 instead of 4 molecules of exposed silver halide for the production of 1 dye molecule

GV.653

are needed. Such couplers contain, for example, a halogen atom such as iodine, bromine or chlorine in the coupling position (See, for example, U.S. Patent 3,006,759). The density of the image is thus obtained by adding the densities of the silver images and that of the Dye images built up.

In order to improve the retrieval of the information content, phenol- or of-naphthol-type color couplers are particularly suitable, the color development of the silver halide with an aromatic, primary amino group-containing developer substance form a quinone imine dye, which is mainly in the red and also absorbs in the green range and has an absorption maximum of 550 to 700 µm (see DT-OS 1 94-6 652).

Phenolic couplers suitable for this purpose correspond, for example, to the following general formula:

OH

in which:

B ₁ and Rp each represent an optionally substituted carboxylic acid acyl or sulfonic acid acyl group, for example an aliphatic carboxylic acid acyl group, an aromatic carboxylic acid acyl group, a heterocyclic carboxylic acid acyl group, for example a 2-furoyl group or a 2-thienoyl group, an aliphatic sulfonic acid acyl group, an aliphatic sulfonic acid acyl group, an aromatic sulfonic acid acyl group , an aryloxy substituted aliphatic carboxylic acid acyl group, a phenylcarbamyl substituted aliphatic carboxylic acid acyl group, or a tolylcarboxylic acid acyl group.

For these types of phenolic color couplers and their preparation, see U.S. Patents 2,772,162 and 3,222,176 and British Patent 975,773 referenced.

409820/0296

For the production of color images together with silver images, aromatic color developers containing primary amino groups are used, such as N, N-dialkyl-p -phenylenediamines and derivatives, e.g. KjF-diethyl-p-phenylenediamine, H-butyl-U-sulfobutyl-p- phenylenediamine 2-amino-5-diethylaminotoluo chlorohydrate, 4-amino-Er-ethyl-ir - (/ 3-methanesulfonamidoethyl) -m-toluidine sesquisulfate monohydrate and F-hydroxyethyl-ir-ethyl-p-phenylenediamine. The color developer sub st an ζ can be used together with black and white developer substances, e.g. 1-pheny1-3-pyrazolidinone and p-monomethylaminophenol, which are known to have a superadditive effect during color development (see LFA Mason, J.Phot.Sei., ΛΛ_ (1963) 136-139) and other p-aminophenol derivatives, as described, for example, in FE-PS 1 283 4-20, such as' about 3-methyl- ^z l -hydroxy-K, N-diethylaniline , 3-methyl-4-hydroxy-H-ethyl-H-ZJ-hydroxyathylaniline, I-methyl-6-hydroxy-i, 2,3,4 - tetrahydroquinoline, 1 -yö-hydroxy äthy l-6 -hydroxy-1, 2,3,4-tetrahydroquinoline, N- (4-hydroxy-3 ^l -methylphenyl) -pyrrolidine, etc. In order to obtain a higher color development speed, one can also use combinations of aromatic color developing agents containing primary amino groups ( see, for example, DT-PS 954-311 and FE-PS 1 299 899); favorable effects are achieved by using N-ethyl-N-2-hydroxyethyl-p-phenylenediamine together with N-butyl-IT-sulfobutyl-p-phenylenediamine, 2-amino-5-diethylaminotoluene chlorohydrate or N, K-diethyl-p- phenylenediamine chlorohydrate.

The developer solution can also contain the usual other additives, such as sodium sulfite and hydroxylamine or its derivatives, hardeners, anti-fog agents, e.g. Benztriazole, 5-Fitrobenzimidazole, 5-NitiOindazole, halides such as potassium bromide, silver halide solvents, tinting and strengthening agents, solvents such as »dimethylformamide, Dimethylacetamide and E-Hethy! Pyrrolidon for chemical bath additives, the difficult solution when preparing the developing bath are to be brought or tend to precipitate when the solution is standing, etc.

_GV . ₆₅₃ 409820/0296

The radiation-sensitive to be used according to the invention Emulsions can be poured onto a wide variety of substrates, such as foils made of cellulose nitrate, cellulose esters, Polyvinyl acetal, polystyrene, polyethylene terephthalate and others Polyester plastics, as well as papers coated with ^ -olefins, such as paper coated with polyethylene or polypropylene.

Preferred supports contain a linear condensation polymer; an example of this is polyethylene terephthalate.

Those used in the present recording materials Carriers can be coated with adhesive layers in order to ensure the adhesion of one or more gelatin-silver halide ion layers to improve on it. As already mentioned, the carrier can be colored. According to the present invention, blue Dyes preferred. Blue polyester resin carriers are known.

The mechanical strength of those extruded in the molten state Polyester type backing can be improved by stretching. In some cases, such as those in GB-PA 1 2 ^ 4- 755 are described, the carrier can carry an adhesive layer in the stretching stage.

Suitable adhesive layers are known from silver halide photography. With regard to the use of hydrophobic film supports reference is made to the composition of adhesive layers, the. in GB-PS 1,234,755.

According to this patent, a hydrophobic film support 1) has a layer that is directly on the hydrophobic film support adheres and contains a copolymer that consists of 45 to 99.5 % By weight of at least one of the chlorine-containing monomers Vinylidene chloride and vinyl chloride, from 0.5 to 10 wt .-% of at least one ethylenically unsaturated, hydrophilic monomer and from 0 to 54.5% by weight of at least one other copolymerizable, ethylenically unsaturated monomers is formed, and 2) a layer in a weight ratio of 1: 3 to 1: 0.5 a mixture of gelatin and a

GV.653 409820/0296

Copolymer from JO to 70 wt .-% butadiene with at least contains a copolymerizable, ethylenically unsaturated monomer. -

The exposed radiographic materials according to the present invention Invention are preferably treated in an automatic processing device for X-ray films, in which the photographic Material can be fed from one processing unit to the other automatically and at a constant speed may ', however, it will be understood that the X-ray imaging materials described herein can also be outside of those mentioned above automatic processing equipment can be handled in many ways, such as using the known, customary, manual multi-container process.

For ordinary emulsion making processes and use for particular emulsion ingredients, reference is generally made to "Product Licensing Index", December 1971, in which the following terms are dealt with in detail: I / II emulsion type and manufacture of this material

III Chemical sensitization

IV development modifier

V Veil Protectants and Stabilizers -

VI Developing Substances

VII hardener

VIII Binders or Polymers for Silver Halide Layersi and other layers

IX Antistatic ^ layers

X carrier ■

XI plasticizers and lubricants,

XII casting additives

XV Spectral sensitizers for silver halides XXIII Parb material ingredients

XVI Absorbent and filter dyes XXI Physical Development Systems and

XVII and XVIII ingredients and coating methods

409820 / 029S

The present invention includes the use of fluorescent Gadolinium compounds in all types of neutron detection, neutron energy conversion and neutron image recording. A very interesting use of the self-luminous compounds is in the conversion of neutron energy into visible light in image intensifier tubes and in so-called neutron beam image converters in analogy to X-ray image converters, such as in U.S. Patents 3,4-03,279 and 3 617 74-3.

The structure of the neutron beam imager is fundamental the same as that of the X-ray image converter.

The neutron energy conversion takes place in such a neutron beam imager with fluorescent, electromagnetic !: Radiation in a photoelectron generating tube in one Vacuum or at reduced pressure instead; which contains tubes the neutron-absorbing screen in contact or optically coupled, e.g. with fiber optic means or a lens system with a photocathode whose image-wise emitted photoelectrons are electrically or magnetically focused to a luminescent, electron beam sensitive screen meet. The neutron image is first converted into a fluorescent light image, which, with all its brightness variations, is converted into an 'electronic image' with a corresponding density Variations is transformed. The acceleration of the electrons in the electrical focusing field essentially brings about a Reinforcement of the entire "Lichf" flow with oneself. With others In words: the greater the kinetic energy this Own electrons when they hit the cathode luminescent screen, the more light they give off. This is why these tubes are also called "image intensifier tubes".

Appropriate x-ray image conversion or intensifier tubes that. Containing rare earth oxysulfide phosphors containing gadolinium and at the neutron image conversion according to the present invention are available from S.P. Wang et al in IEEE Nuclear

409820 / Q296

Science Transactions, February 1970 * pp.4-9-56.

The fluorescent gadolinium compounds are suitable for the technical term "of neutrons of any energy content, eg for the detection of" cold " ¹ neutrons. (^ CQ ,, 01 eV)," thermal "neutrons (0.01-0.5 eV) >"epithermal" neutrons (0.5-10keV), and "fast" neutrons (> 10 ka?) *

The fluorescent gadaiinium compounds usually contain in the gadolinium part 15, .68% of the gadolinium isotope Gd 157, which is the most effective "known local neutron sorbent. · The higher the content of this isotope in the self-luminous compound is, the higher the neutron absorption.,

According to a preferred embodiment, the fluorescent contain Gadolinium compounds Gadolinium with more than 15.68% Gd 15? They contain so-called isotope 157-enriched Gadolinium.

The following example illustrates the present invention. Example . -

An X-ray silver bromoiodide emulsion (2 mol% silver iodide) is prepared in such a way that it contains per kg an amount of silver halide corresponding to 190 g of silver nitrate, the mean grain size of which is 0.4 μm, and 7 ^ g of gelatin. The emulsion contains 5 ^ -5 mg 5-methyl-7-hydroxy-s-triazolof1,5-a3py ^{; rirIlidi]} per kg as stabilizing additives: 1 ' ⁶ ' 5 mg 1-phenyl-5-mercaptotetrazole and 0.45 mg mercury cyanide . "

This emulsion is applied to one side of a subbed support made of polyethylene terephthalate in such a way that on the Support a layer of silver halide emulsion containing a 12.5 g of silver nitrate equivalent amount of silver halide per square meter contains. ■ -

A gel at ine-protection layer is applied in proportion to the emulsion layer of 1 g / m2 applied.

The silver halide emulsion material was mixed with the. Goal established, a recording material with opümalei * sensitivity for getting 3 rays.

^^ SiiiHBS - ^^ - ii ^ i ^ iSii ^ ii ^ Silberhalogenidmaterials_ll _i das_ziegen_mit_dem_ein self-luminous gadolinium compound

below described comparison

An X-ray silver bromoiodide emulsion (2 mole percent silver iodide) is used manufactured in such a way that they correspond to 190 g of silver nitrate per kg Amount of silver halide, the mean grain size of which 1.25 µm and contains 74 g of gelatin.

This silver halide emulsion is used for light in the wavelength region from 480-600 nm spectrally sensitized .by. Addition of 150 mg per kg emulsion of the sensitizing dye it with the following structural formula:

^ -CH = CH-CH = '

t:

Br "

(CH ₂ )

The emulsion contains 5 ^ 5 mg per kg as stabilizing additives 5-methyl-7-hydroxy-s-triazolo [1,5-a2-pyrimidine, 6.5 mg 1-phenyl-5-mercaptotetrazole and 0.4-5 mg mercury cyanide.

This emulsion is poured onto one side of a subbed carrier made of polyethylene terephthalate so that on the carrier a layer is obtained which contains an amount of silver halide equivalent to 7 g of silver nitrate per m 2.

409820/0296

A protective gelatin layer is applied to the emulsion layer Ratio of 1 g / m2 applied »

Using_the_ "direct_method ^ 2-

The standard screen is a gadolinium foil with a thickness of

20 do.
- Composition_of_ the_ fluorescent screen material _{± _as_ it_according to}

will. ■

The fluorescent screen "consists of a lyäthylent on a 250 micron thick Po he ephthalathar mounted zträger en fluorine it zenzsohi: -LT latter contains dispersed in a binder, with O ,? terbium% (calculated on the gadolinium) activated gadolinium oxysulfide (GdpOpS). The fluorescent layer is applied to an antihalation layer which contains 5 mg per m2 of the dye NEOPAZCM I ¹ IEE EED (CI. Solvent Eot 119) in a binder that adheres to the polyester.

The fluorescent particles have an average Grain size of 10 µm and are in a layer of 390 g pr: - m2 attached. The thickness of the fluorescent screen is

around

The fluorescent layer is covered with a resin protective layer covered by 15 µm. .

2Ü £ ^ i ^ 5i (direct method)
A thermal neutron beam is emitted from a nuclear reactor through a copper monocrystal. By doing in this manner, one obtains a stream of "monochromatic" neutrons (A = 0.1065 mn) of a flow of 4-.10- ⁷ neutrons / m2 / s for exposure. The ^ -ray strength in this beam is 300 milli-x-rays (mr) per hour).

The silver halide emulsion light-sensitive materials ^GV " ^{653 409820/0296}

were exposed with this "monochromatic" neutron beam through a neutron beam through a test object under the same conditions, "The test object was an iron step wedge with three steps (total height of the three steps = 12.7 mm); each step was located small objects of different sizes, shapes and neutron absorption; -} - coefficients (Br it. J. Applied Phys.,. £ (October 1956) , p. 346, namely objects made of iron, cadmium, indium, gadolinium, polyamide, lead and -Dysprosium.

The standard screen described above and the gadolinium oxysulfide screen were exposed to the test object during exposure with the silver halide emulsion layer of silver halide material I and II kept in contact.

Images of the test item with the same average, optical density was obtained by adding for the combination of the standard screen with the silver halide material I an amount of 4 ·, 2 χ 10 neutrons / cm.2 used and for the combination of the The screen of the fluorescent gadolinium compound with a

n
Halide material II only 1.7 x 10 neutrons / cm2, so that the latter combination must be regarded as about 2 ^ 0 times more sensitive for neutron detection and recording than the combination with the standard screen.

In a further experiment, which was carried out according to the transmission method, a dysprosium screen was used as the converter screen, which becomes radioactive after the neutron bombardment and emits β- rays. The dysprosium screen was made with

10
exposed to a dose of 3.6 χ 10 neutrons / cm2.

The dysprosium screen exposed in this way was 5 minutes after the Neutron irradiation for 3 hours in direct contact with the silver halide emulsion layer of Material I described above. The optical density obtained was that same as the one you would use with the direct method the silver halide material II, combined with the gadolinium

4Ö9820 / Ö296

^GV - ⁶ 53- BAD

oxysulphide screen, - which, however, had an amount of neutrons received that 2000 times smaller than that on the dysprosium screen was attached.

409820/0296

Claims (1)

- 34 -.
Claims -. (ΐ J Procedure for recording neutron images or for Detecting neutrons, characterized in that it includes the following steps: O) neutron irradiation of an intensifying screen, the one fluorescent when hit by X-rays Contains gadolinium compound, with neutrons and (2) projecting fluorine, there is central light from the impact the neutrons originate on the screen, on a photographic material or the detection of the fluorescent light with the human eye or with a photosensitive, electronic light detector. . 2. The method according to claim 1, characterized in that the gadollnium compound the oxide, an oxyhalide or the Is oxysulfide of gadolinium. 3. The method according to claim 1 or 2, characterized in that that as a gadolinium compound he uses a self-stuck substance is in what gadolinium as a "guest" metal and at least one other rare earth metal is contained as a fluorescence-activating metal. 4. The method according to any one of claims 1 to 3j, characterized in that that a fluorescent gadolinium oxysulfide or Gadolinium oxyhalide substance is used which is activated with at least one other rare earth element. 5- The method according to any one of claims 1 to 4, characterized in that that as activating metal at least one of the metals terbium, dysprosium, erbium, europium, holmium, neody :, Praseodymium, samarium, thulium and ytterbium is used. 6. The method according to any one of claims 1 to 5 _r characterized © in that the gadolinium compound corresponds to the following general formula: GV 653 4 O 9 8 2 U / O 2 9 6 in which:. M at least one of the rare earth metals dysprosium, erbium, europium, holbnium, seodymium, praseodymium, samarium, terbium, Thulium or ytterbium,
X sulfur or halogen,
η the numbers between 0.0002 and 0.2 and w 1 when Σ is halogen, or 2 when X is sulfur. 7 · The method according to claim 6, characterized in that the Gadolinium compound terbium-activated gadolinium oxysulfide is. 8. The method according to any one of claims T to 7 _5, characterized in that the fluorescent gadolinium compound contains gadolinium with a Gd 157 isotope content greater than 15.68 % . 9. The method according to any one of claims 1 to 8, characterized in that that the netxtron-absorbing screen has one or more fluorescent gadolinium compounds in a mixture with other self-complexing substances that fluoresce, when struck by x-rays and / or,, ^ -rays will. 10. The method according to any one of claims 1 to 9 »characterized in that that when recording a neutron image, a photo-sensitive silver halide is imaged on drawing material is irradiated with the eluorescent light while it is kept in contact with the neutron absorbing screen. .Method according to any one of claims 1 to 10, characterized in that that the neutron absorbing screen in the JOrm a layer attached to a support, or a self-supporting one Layer or foil. ^{GY 653} '409820/0296 12. Method according to claim. 11, characterized in that the Layer or foil the gadolinium compound in shape of particles - which are dispersed in a binder. 13 · The method according to claim 12, characterized in that the Particles range in size from 1 to 20 µm. 14. The method according to claim 12, characterized in that the layer has a thickness of 10 to 300 µm. 15. The method according to claim 12, characterized in that "the binder is contained in the layer in a ratio of 5- ^ 5 % by weight with respect to the fluorescent material. 16. The method according to claim 11, characterized in that the neutron-absorbing screen in the fluorescent layer, a top layer, an atrial tendon or the Carrier, or in several of these elements contains a sharpness dye, which by the contained in the screen Fluorescent light emitted by self-luminous substances absorbed. 17. The method according to claim 16, characterized in that the screen emits green light and the sharpness dye is HEOZAPQET I ¹ IEE EED (CI. Solvent Eot 119). .18. Method according to any one of claims 1 to 17, characterized in that that the neutron absorbing screen containing a gadolinium compound in connection with Another, neutron-absorbing metallic, glass-like or granular screen is used. 19. The method according to any one of claims 1 to 17, characterized in that that the neutron absorbing screen is used in conjunction with a metal screen, which by Neutron bombardment becomes radioactive. 409820 / 029-6 20. The method according to any one of claims 1 to 17 j, characterized in that that the neutron absorbing screen is used in conjunction with a metal screen that has a $ Teutro- ~ has an absorption coefficient that is at least as high like that of lithium. 21. The method according to claim 10, characterized in that the silver halide photosensitive material one to one Contains carrier coated silver halide emulsion layer. 22. The method according to claim 10, characterized in that the photosensitive silver halide material is a silver halide emulsion layer on each side of the backing. 23- The method according to claim 21, characterized in that the photosensitive material contains one or more filter dyes which reduce the sharpness of the silver image obtained improve in material. 24. The method according to claim 23, characterized in that the dyes are chemical and / or physical Have properties that they can be used in one of the processing baths, which are used for the silver halide photosensitive material can be removed or decolored. 25- The method according to claim 23, characterized in that the dyes are contained in a hydrophilic colloid layer. 26- The method according to claim 25, characterized in that the dyes are contained in a hydrophilic colloid layer between the silver halide emulsion layers, if a double-sided coated material is used and / or contained in the silver halide emulsion layers themselves are. . " 27. The method according to claim 23, characterized in that the dyes in one or more adhesive layers or in «.653 409820/0296 an antihalation layer on each side of the support are. 28. "The method according to claim 23, characterized in that the dyes are contained in the carrier. 29 · The method according to claim 10, characterized in that the neutron-absorbing screen and the photosensitive Silver halide & material form an integrated arrangement. 30. Combination according to claim 10, characterized in that the neutron absorbing screen is separated from the photosensitive screen silver halide-containing ma1a? ial arranged is. 31- The method according to claim 10, characterized in that the silver halide has been spectrally sensitized. 32. The method according to claim 10, characterized in that the silver halide is a silver bromoiodide with an average grain size of about 0.1 to 5 µm. 33 · The method according to claim 10, characterized in that the silver halide emulsion layer has a color coupler Formation of a dye with an oxidized p-phenylenediamine developing agent contains. 34-- Procedure according to claim. 10, characterized in that the silver halide photosensitive material a lot Contains silver halide, which is equivalent to about 3 to 8 grams of silver per square meter. 35 · Method according to any one of claims 1 to 9 _}, characterized in that the conversion of neutron energy into fluorescent electromagnetic radiation is used to obtain an optical image which is photographed with a camera or recorded with a television tube. GV.6535 409820/0296 36. The method © mass claim 35 _5, characterized in that the optical image is amplified before it is viewed or photographed with an image intensifier tube. 37 · The method according to any one of claims 1 to 9 _5, characterized in that the neutron energy conversion into fluorescent, electromagnetic radiation takes place in an image converter which, under a vacuum or reduced pressure, contains the neutron-absorbing screen in contact or optically coupled with a photocathode whose image-wise emitted Photoelectrons are electrically and / or magnetically focused on a luminescent, cathode ray sensitive screen. 40982070296