A METHOD FOR PRODUCING THE RADIOLOGICAL IMAGE OF AN OBJECT, PREFERABLY FOR USE IN MATERIAL TESTING, AND A MEANS FOR ITS PERFORMANCE

Abstract: Improved method in the field of transmission-type radiology making it possible to apply this method even in cases where its application has up till now not been possible for disturbing factors, e.g. if determining features at hidden spots or if distortion is caused by media filled inside or surrounding the object to be tested. It facilitates among others the determination of: the wall thckness of pipes; the presence of deposits, encrustations, and the like; the formation of drift media. The otherwise known method is completed according to the invention by inserting into the radiation path - between the test body and the receiver - a modifying body which consists in a laminated thin layer package obtained by packing at least three thin flat sheets upon each other and arranged in a manner that the axis of the radiation path is including an angle of maximum 60<o> with the normal of the thin layer surface, preferably the said axis and the said normal are lying collaterally with each other. When evaluating the thus obtained radialogical image, the substantial and geometrical features of the modifying body are also taken into consideration.

Description: A METHOD FOR PRODUCING THE RADIOLOGICAL IMAGE OF A OBJECT, PREFERABLY FOR USE III MATERIAL TESTING, AID A MEΔ3-IS FOR ITS PERFORMANCE The invention is related to a method making it possible to apply the radiography and radioscopy successfully as a test method for determining the state and structure of such objects whose features can not be tested with suffic¬ ient accuracy by the methods according to prior art /the known radiological test methods included/. The invention can advantageously be used in the technology of material testing, i. e. in examining the structure and/or the state of industrial materials, and the invention is hereinbelow disclosed with reference to this advantageous field of ap¬ plication. In can, however, from the below be seen by men ordinarily skilled in the art that the use of the invent¬ ion is not restricted to this preferred field of applic¬ ation: the invention can, mutatis -autandis, be applied whenever the pattern of a recorded or displayed ray iiaage forms as a consequence of the absorption of radiological particles penetrating into the specimen to be tested /here¬ inafter: test body/, i. e. when the spatial shape and structure of a body can be determined by way of the so- -called transmission radiology. Auiong the special advantages of the invention, there may be mentioned that - the e surement results are not affected by the working temperature of the tested specimen, and - distortions due to the presence of other media either surrounding the test body or located in its interior can well be compensated. The industrial application of the invention may therefor specially be expedient when measuring the wall thickness of pipes or bodies constituting parts /componen s/ of ap¬ paratuses used in the chemical technology. A thus performed wall thickness measurement can be completed by some diag- ^*w o nostical tests as usually performed when determining the state of materials and in this case, the detection of the presence of corrosion, deposits, encrustations, drift media, and the like can also be performed with sufficient accuracy if proceeding according to the invention. A specially preferred field of application is the determ¬ ination of features appearing at hidden spots: the exam¬ ination of heat isolated bodies, duplicatures, cladded ar¬ ticles, bodies buried within walls such as tube stills, and the like. The methods according to prior art such as ultrasonic detection, ther ovision, nuclear measurement have if applied at such spots proved to be insufficient and troublesome, sometimes they could not at all be per¬ formed, whereas the method according to my invention can even at such spots be performed in a manner that the details sought for are reproduced with a suffucient accur¬ acy and the compensation of the above mentioned disturbing factors can also sufficiently be performed. The main feature of my invention is apparent with any kind of its application, be it wall thickness measurement or the determination of other features characterizing the state of a test body: transmission type radiology is ap¬ plied detecting an Z-ray or ^ -raj image which can immed¬ iately or intermediately be reproduced on a film or an image screen showing the image of the examined specimen or an examined sampling spot thereof. The 7"-ray can be ob¬ tained from a radioactive isotope or generated in a part¬ icle accelerator. The method will hereinbelow more partic¬ ularly be set forth referring /as example to which my in- vention is not restricted/ to the radiographic reproduct¬ ion wherein a film image is reproduced from the ray image and this film image is then evaluated. If the film image is obtained by the so-called projection method, the pro- jection/s/ of the cross-section/s/ of the examined specimen can be seen and evaluated: the said projections can either OMPI immediately be measured taking into consideration the mag¬ nification factor, or the thickness belonging to a given projection can be determined using suitable -instruments. This method is, as such, belonging to prior art but the nown ways of its performance can not afford the wanted accuracy: the different intercepts of the cross-section should represent the material thickness, however, their values are dependent on their position in the cross-section considerably differing from each other. Let us take an example. If the object to be reproduced on the film is a pipe having a diameter of 324 mm and a wall thickness of 10 mm, the material thickness will on the film be repres¬ ented by intercepts of a cross-section each intercept being taken along a straight. Each straight is representing a certain depth within the pipe: a certain distance from the pipe surface along the radius towards the axis of the pipe, i. e. the centrum. It is obvious that the projection of a spot lying on the surface of the pipe will give an "in¬ tercept" of 0,00 mm. Proceeding towards the centrum, the following values can be measured along the different straights representing a certain depth each: Depth Intercept 0,5 mm 25j 4 mm 1,0 mm 35,94 mm 1,5 mm 44,00 mm 2,0 mm 50,75 mm 9,5 mm 103,32 mm 10,0 mm 112,07 mm 25,0 mm 41,23 mm centrum 20,00 mm. The intercept for a depth of 0,4 mm has approximately the same value as the one found for the centrum! On this image reproduced according to prior art, only a wall thickness of about 3 mm is really visible whereas the other portions can not be determined. Moreover, the well-known phenomenon of divergence is further affecting the accuracy: if deviating from the axis of the main beam along the axis of the pipe, the length of the intercept is increasing with the increase of the deviation. In the above given example, e. g., a deviation of 30° at the depth of 10 mm will increase the length of the corresp¬ onding intercept from the above given 112,07 mm up to 129,41 mm. This known method has in the international practice of wall thickness measurement proven to be a failure; it is not included into the corresponding stand¬ ard provisions and recommendations. There have been proposals to facilitate the correction of erronous values by comparison with a reference body also reproduced on the film. Compensating forms, /tin/wedges have been used with the conventional testing of joints or welds because such structures can not be controlled dis- cretionarily and the computation of the intercepts found on the film can not be performed with sufficient speed and accuracy. " .'. r ith other applications, the reproduction of a reference upon the film was performed by applying borings of different depths on a flat plate presuming that the blackening caused by the projection of the said borings will be proportional to the. depth of the given boring. This supposition was, however, erronuous because of the scattered radiation reflected from the wall of the boring which increased the intensity of the blackening. Out of the different variants of reference objects for such purp¬ oses, that one seems to be most important which was pub¬ lished in -February, 1977, in Materials Evaluation by Kra- licki. The author reproduced - besides the examined spec¬ imen - also some exactly calibrated reference /lead/blocks on the film, measured the wall shadow of the test body and the shadow of the corresponding reference object and der¬ ived therefrom the correct value of the wall thickness. This method is restricted in the range of pipe dimensions -gTm E ι4 j - W1PO _ _ {[about 250-300 mm diameter and 20 mm wall thickness at mostj and in so far that the radiation source —-■- film distance shall be the greatest possible. Considering the advanced known methods, it can be seen that there is in prior art no radiological method which could reproduce a really proportional projection on a single film independently of the dimension of the pipe. The improvement according to the invention consists in that a combined reference system is reproduced on the film bes- ides the pipe to be tested, the said reference system con¬ sisting of several thin metal sheets /foils/ laminated on each other. It may be expedient to make the foils of a metal the density of which exceeds the one of the test body considerably; the thickness of the different foils packed upon each other shall not necessarily be identical but the use of foils of identical thickness offers advant¬ ages in the computation and data processing. If the foils are susceptible to fold, it may be expedient to mount same on carrier layers such as paper sheets. The reference ob- ject according to the invention which comprises several foils packed upon each other is modifying the radiological picture and we refer thereto in the following as "modifying body". It is not necessary to make the foils of the same material the test body is made of, and the single foils forming to¬ gether the modifying body can also be made of different metals provided that no such disturbing factor will thus arise which can not be taken into consideration in the evaluation. Though the influence of the modifying body on the film image can be reckoned in a conventional manner, e. g. considering the surface density, the thus obtained value should not be considered an immediately accurate one since the modifying body affects also the influence of the scat- tered radiation and - under certain conditions - the secon- dary radiation. It is therefor expedient to perform a series of tests and determine by its average how many foils are exerting the same influence as a unit /e. g. 1 mm/ of the wall thickness and, thus, causing a similar blackening of the film. One shall be aware of the fact that the number of layers exerting this equal influence is not increasing with the thickness at a linear rate; the number of layers forming together the equivalent of a 20 mm thickness is, e. g. not the double of the corresponding number equalling a 10 mm thickness. If computing the necessary number of foils accurately, a reference object of known thickness can be reproduced on the film offering not only the advantage of a comparable reference image but also extending the range of visibility since it is modifying the contrast conditions. In the ind¬ ustrial practice an accuracy of + 0,1 to 0,5 mm is usually sufficient; in the course of the test process, the lower and upper limit of the v/anted visibility /thickness range/ shall be established taking into consideration the relative position of the selected thickness samples with respect to the inner and outer surface of the pipe. Let us again refer to the above discussed example: the pipe of a 324 mm diam¬ eter and a 10 mm wall thickness. If, e. g. , a + 0,5 mm ac- curacy is required, a visibility range of 25 mm to 103 mm is necessary, i. e. a 25 mm material thickness shall already be visible at the outer surface of the pipe whereas a 103 mm wall thickness shall still be visible at the inner sur¬ face of the pipe; if this condition is met with, the wall shadow can be determined with a + 0,5 mm accuracy. A 1/250 to 1/500 portion of the examined wall thickness can al¬ ready be made visible, i. e. measurable /dependent on the quality of the radiation source/ if the combined refer¬ ence object, the modifying body is suitably designed and applied. ' The wall shadow can be reproduced .not only by way of the above mentioned projection method; the so-called double wall technique can also be applied: the film is bearing on the cylindrical superficies of the pipe adopting, thus, a cylinder-jacket inflexion. The fact that the wall shadow is geometrically transformed does not yet mean that it can not be determined. The accuracy may slightly be affect ed thereby but the range of visibility will considerably increase since there is no need to insist upon the seldom applied projection method. The radiation source — 9 ~ ~- film distance can, thus, more freely be chosen its range being only restricted by the sharpness requirement. Besides the reproduction of the wall shadow on the film and its evaluation, it is also expedient to determine the intercept of the pipe cross-section. This can be reckoned considering the blackenings on the film provided that all data for the computation of same are at hand. In this case there is no need to know the values of the visible wall projections. It is sufficient to know the co-ordinata of the reproduction, the exposure data, the data for trans¬ forming the modifying body, and tiie diameter of the pipe to retrieve by computation the intercept belonging to any spot of the film image. The characteristic behaviour of the intercept diagram affords the possibility of fur- ther analytical determinations. It can be established if the inner and outer superficies of the pipe wall are not concentrical and/or not coaxial ones but the wall thick¬ ness is with respect to the straight intersecting the radiation source and the film plane positioned in a manner that one side has a thinner, the other side a thicker wall whereas the projection of both wall thicknesses on the film are identical ones. The analysis of the intercept diagram is also unambiguously showing which one is the thinner and which one the thicker side. This distinction could by methods according to prior art not be established. If the modifying body in itself can not yet afford the reliable reproduction of a complete projection with a sufficient accuracy, an additional means can be applied in order to compensate the disturbing factors. The comp- ensator is a homogenuous body the substantial features of which or rather its density being equal to or at least ap¬ proaching the one of the test body /if the test body is a pipe, the said density is, of course, the one of the wall of the pipe/. The compensator is in effect a stand- ard wedge: it can really be shaped wedge-like or it can be a plate bordered at two opposite planes by parallel super¬ ficies but cut askew so that at least one of its sides is bordered by an oblique plane. The thickness of the plate, i. e. the height of the wedge has its proper size if equalling the length of the longest possible intercept which may occur with a given test body. The compensator shall be positioned on the film in a man¬ ner that the longitudinal projection of the oblique plane be lying perpendicularly to the projection of the axis of the pipe. It shall, if possible, be longer than the dist¬ ance between the axis of the pipe and its outer surface so that a film image of the oblique side wall of the com¬ pensator can be obtained independently of the film image of the pipe wall. The thus obtained film image is differ- ing from the one according to prior art in so far that the inner wall thickness will appear at the edge of the wedge whereas the image of the outer wall will appear at the opposite, thicker end of the wedge. The compensator is a homogenuous body having a density comparable to the one of the test body and that one of its superficies facing the radiation source is including an angle /0° < * <90°/ with the normal of the axis of the radiation path. If a non-cylindrical body is examined, the value of the angle Ψ lies between 30° and 60° /the limit values included/. If a cylindrical body or a cylind- ric pipe is examined, the angle be complying with the equation . wherein D' is the maximum length of the test body along the normal of the axis of the radiation path and L > is the maximum length of the path along which the radiation is passing through the coherent medium forming the test body. The visible length of the outer wall may correspond to the width of the compensator measured between the parallel superficies whereas the visible length of the inner wall may extend from the edge of the wedge to the margin of the film. The projection of the other portions of the pipe can be seen on the area covered by the projection of the oblique side of the compensator in a manner that each sel- ected blackening value is following the trace of the in¬ tercept curve of the examined pipe: as a matter of fact, the intercept curve can be traced out on the film. If the thickness of the compensator is not chosen to be of the ideal size /i. e. the equivalent of the longest possible intercept/, the intercept curve may become incomplete but can nevertheless be evaluated even if there were also some inaccuracies as far as the performance of the exposure, the nominal equivalence of the combined modifying body, and the scattering, caused thereby are concerned. Even the smallest portion of the intercept curve - if only this portion is accurate - is unambiguously representing the numerical proportion between the diameter and the wall thickness of the examined pipe. The oblique part of the compensator can - in its capacity as standard wedge - also be utilized for intermediate thickness measurements. That portion of the compensator being reproduced aa a film image independent of the one of the pipe is also including all blackening states appearing in the film image of the pipe. All spots of identical blackening inten- sity - appearing on the one hand on the pipe image and on the other hand on the wedge image in a mutually comparable state - can be considered as spots of equal thickness. The corresponding thickness values can easily be determined on the standard wedge: if, e. g. , the angle is chosen to be 45°, the material thickness value is a linear func¬ tion of the distance from the edge of the compensator. The thus obtained value can then be utilized to compute the effective wall thickness of the pipe. The film image produced according to the invention allows the utilization of the magnification up to several times the unit so that the value of a joint gap can also be est¬ imated therefrom, e. g. in case of bearing fits etc. It can be seen that the invention can, thus, make it possible to survey or recognize the inner structure of an object, e. g. an apparatus, even if the density is in different spots of the inner structure significantly different. The blur due to the movement of the object is a well-known phenomenon in radiography. The movement of the object during the examination - affecting the position of the projections to be reproduced - increases the unsharpness of the image, sometimes to a measure that the film can not be utilized. This usually unpleasant /often deleterious/ phenomenon can, however, be utilized in the method according to my invention, e. g. in order to detect the amplitude of vibration of the specimen in the projection plane; this measurement is expediently performed in combination with magnification. My invention can, thus, serve the examination of revolving constructions susceptible to abnormal mutat¬ ions of acceleration /perturbations/. Let us take e. g., a gear box revolving normally aϋ a steady speed but its acceleration constant being perturbed for defects in its in¬ ner structure such as axle bending, defects of toothes in a gear wheel and the like. This phenomenon can be detected if a film is together with the combined modifying body laid on the revolving shaft /or a cylinder-jacket revolving therewith/ and a radiation is directed towards the film collimated to form a narrow band extending, if possible, over the whole width of the film. The acceleration mutations produce black and white bands on the film contrasting with the otherwise evenly disperse blackening; the position and the number of such bands al¬ low to estimate the features of the anomaly. Sometimes the proper number of layers to form the comb¬ ined modifying body can not be computed with sufficient accuracy. In this case, the compensator is expediently arranged in the radiation path between the radiation source and the film in a manner that the blackening transition varies along the width of the film, i. e. from one mar¬ gin towards the opposite margin of same. This way, there is a strong probability that a suitable area will be ob¬ tained where the collimated bands can appear and the examination can be performed. The anomaly detection-as set forth hereinabove can be used when the well-known /more easy/ methods such as the audio frequency rattling analysis can not be applied. It can be seen that the subject matter of my invention con¬ sists in an improved method for producing the radiological /radiographic or radioscopic/ image of an object, prefer¬ ably for use in the radiological testing of industrial mat- erials, which comprises arranging the specimen to be tested /test body/ in a certain spot of a test area /test spot/ in front of a radiation receiver; transmitting radiation towards the said test spot, and evaluating the thus ob¬ tained image taking, if necessary, into consideration the known properties of the test body. The improvement consists in that a modifying body is ar¬ ranged in the radiation path between the test body and the radiation receiver, the said modifying body consisting in a laminated thin layer package obtained by packing thin flat sheets /foils/ upon each other and being arranged in a manner that the axis of the radiation path is including an angle of 0° to 60° with the normal of the thin layer surface, preferably the said axis and the -said normal lying collaterally with each other, and the substantial and geo- metrical features of the modifying body are in the course of evaluating the radiological image also taken into con¬ sideration. In a preferred embodiment a homogenuous body /compensator/ is arranged in the radiation path between the radiation source and the radiation receiver, i. e. before or behind the said test body, the said compensator being cut askew and the oblique portion of its superficies is facing the radiation source and at the same time including an angle ^f /C°< <9C 0 / with the normal of the axis of the radiat- ion path whereby 30° . ^ 50° if the specimen is a non- -cylindrical body and tg *f = D'/L' if a cylindrical body /pipe/ is examined /D' is the maximum length of the test body along the normal of the axis of the radiation path and L' is the maximum length of the path along which the radiation is passing through the coherent medium forming the test body/. The invention is also related to the modifying body com¬ prising a package of three or more thin flat sheets each sheet having a practically homogenuous structure and a density equalling or - preferably - exceeding the density of the object to be tested, the said sheets being packed upon each other and integrated into a laminated thin layer body by sticking, gumming, ther opressing, or the like. The reducing to practice of the invention can well be il- lustrated with reference to the attached drawings wherein the symbols are representing the following notions: A, 3, C image variants I ? radiation ' receiver /film/ K modifying body representing a reference size H compensator representing a reference size /stan OMPI ard wedge/ L specimen representing a length value M, Mj intercept representing a length value; the path along which the " -ray is passing through the bodies L, K and H, respectively, /i-1,2, •••/ 0 origin P collimator R radius S wall thickness U shaft of a revolving body V supporting belt fixing the modifying body and the film on the revolving body Q, Q_ centrum /i«l,2 .../ f position of the radiation source O angular velocity of the steady revolution ^f* ideal position of the peak of the intercept Fe iron Pb lead X whole wall thickness crossed by the radiation X' thickness of the modifying body db number of sheets forming a modifying body mm millimeter ζ, _ spots on the superficies of the pipe (£-1,2,.. L height of the modifying body according to prior L » height of the modifying body according to the invention The figures can easily be followed by men ordinarily skilled in the art after having studied the specification set forth hereinabove so that only minor remarks are still necessary to explain them: Figure 1: The non-linear equivalence diagram of a Pb modifyi body to a Fe specimen Figure 2: The intercepts M and their envelope /intercept cur in case of a pipe of a diameter R and a wall thickness S Figure 3: Intercepts and intercept curve of a homogenuous plane body having a density as the pipe in Fig 2 Figure 4: The influence on the intercept M of the modifying body K having a considerably higher ^-^ %ϊ density /Pb to Fe/ as the pipe in Fig 2 Figure The shape of the intercepts M^ and the intercep curve as a function of the distance of the radiation source /A=far away; B=near/ in case of concentrical pipe walls -figure Modification of Figure 5 caused by non-concen¬ tricity of the pipe walls -~- ii gure 7. The relative position of a specimen L with a wall thickness S, a compensator H, a modify¬ ing body and the film F shown in three dif¬ ferent projections /variants A, 3, 0/; Ϋ* is showing the position of the radiation source figure The arrangement is the one shown in Fig 7; the exposure was performed to meet with the intercept II at the spot of greatest thickness; the intercept curves /envelopes/ represent spot of identical blackening; the A variant is showi the use of a properly sized compensator H, the 3 variant the image obtained with a smaller co Densator e variant the one wit a greater compensator -H Figure : The conditions are the same as in Fig S but for diminishing the exposure Figure 10 : The conditions are the same as in Fig 3 buτ for increasing the exposure Figure 11: Reproduction of the ray image obtained when examining a revolving body arranged as shown in Fig 12; band changes /black-white/ are shown: the A variant is obtained without using a com¬ pensator H, the B variant is obtained when applying the standard wedge Figure 12: A revolving body having a nominal angular vel¬ ocity ~ is examined; the examined specimen L is provided at the shaft U with a film F and a modifying body K fixed by a supporting belt V. OMPI A narrow slot shaped collimation is performed by the colli ator P facing the radiation source positioned a Y /the col¬ limator is for practical reasons shown with enlarged dimensions/. If a compensator H is applied, the perturbation will appear as shown in the B variant of Fig 11, if it is not ap¬ plied, the image is as shown in the A var¬ iant Fig 1 is, thus, showing how many pieces of foils are togetner equalling the influence of a given material thicϊαiess of the specimen on the film image /i. e. resulting in equally black¬ ened spots/. The curve exemplified in Fig 1 is taken from a specimen made of iron and foils made of lead and mounted on paper sheets as individual carriers. In the given example, each division of the scale represents a 20 mm of wall thick¬ ness on the abscissa and 100 foils of lead on the ordinate. It can be seen that a. 10 mm wall thickness would be equalled by a 100 foils package, 20 rmn o 240 foils, and 30 mm ' o 430 foils package, respectively. This is, of course, only an example since even in case of iron and lead, the substant¬ ial features may vary from each other in different applic¬ ations, furthermore, the foils may as already mentioned be of different thickness, etc. In an effective system already reduced to practice, the corresponding data for Fe-Pb have been 44, 112, and 192 foils, respectively. Let us now compare Fig 5 with Fig 2. It can be seen at Fig ~ - that the « -ray is crossing the pipe at different paths. If tne radiation source is far away as supposed in the side A of Fig 5, the paths will be lying approximately collaterally with each other. If, however, the radiation source is lying nearby such as at the spot Y , the deviation in luence already dealt with hereinaoove will occur, t e paths will deviate from each other according to grades along a circle with the centrum at i /see the side 3 of s'ig /. Accordingly, the «ar away case would result in the reproduction /shown above the pipe/ on side A of Fig 5 wherein the intercept ϊ-, is the longest one since the path of the V-ray across the wall of the pipe is a continuous one from the spot £-, to the spot ^2 of the superficies of the pipe. Proceeding towards the outer surface of the pipe, it can be seen that the in¬ tercept ¥ι O- between the spots 2,j and 2 "r ± s also rep - ■ roduced along a continuous path but it is considerably shorter than the intercept I-I-^ whereas if proceeding towards the axis of OMPI ^SSι the pipe /centrum , a. g. in the plane including the spots ^ 5 r - and Z o ,- . ' the path within the coherent medium constituting the pipe is consisting of two parts , i. e. the path between S and i r /- on the one hand and between <? C 0 and έO on the other hand and the sum of the two parts of the path results in the intercept lr- considerably shorter than H, and approximately equalling the intercept ϊv-. ■ The reproduction as shown in i 5 at the side A is, thus, showing a film image obtained by tne main oeam of a far away source not sub ect to distortions for deviation. his case is also shown in Fig 2. If now arranging a modifying body in the radiation path being a compact plane body /such trials have already bean performed in prior art/, the reproduction will alter as seen in Fig 3 where the intercepts H of the pipe reproduction and the ones of the modifying body reprod¬ uction are simply summed up. Thus, no useful further inform¬ ation can be obtained v/ith respect to the case shown in Fig 2. If, however, a modifying body according to the invention is used, the reproduction will realljr be modified. It can be seen from Fig 4 that that part of the modifying body extend¬ ing outside the outer wall of the pipe is appearing in a sim¬ ilar manner as the corresponding part of the modifying body according to p £ -rior art in Fig° 3 / and m- are in ef ect equalling/ but where the specimen and the modif^ring body are together reproduced, the resulting intercepts l-l in Pig ~ are representing the linearsum of the thicleiess of the spec¬ imen and the compact modifying body whereas the resulting intercepts in Fig 4 are representing a non-linear combin¬ ation of the summed up individual values since the sums of the specimen intercept and the modifying intercept at the different spots of the pipe are subject to the non-linearity as shown in Fig 1. If the path of the "■ < -ray within the spec¬ imen is a longer one, the higher thickness value means that the equivalent of same can only be obtained by a greater number of foils than in case of a shorter path. The modifying body remains, however, unchanged. 'Thus, the longer the ef¬ fective path within the coherent medium forming the specimen, the smaller the addition performed y the modifying body ac¬ cording to the invention so that the resulting intercept is reduced depending on the path within the specimen in accord¬ ance with the curve shown in Fig 1. It can also be seen from Fig 5 that the effective position of a radiation source is also determining the position of any intercept along the abscissa so that the .intercepts in the A side of Fig 5 are occupying an area having a shorter baseline along the abscissa than the intercepts dispersed along the same radius shown at side 3 of Fig 5. 3e now the posi of the radiation source the same /i. e. ι / but let us examine a specimen where the i n^ and outer wall surface are not concentric ones: the reproduction will vary as though the radiation source will have been slightly transferred /see Fig 6/. Moreover, not only the position would change, but also t:ie length of the intercept will diminish as though obtained oy another grade of deviation. Thus, not only the excentricity of the pipe wall can be observed out it can also e determined which side is the wall thicker on and which side thinner on. Fig 7 is showing the mechanism of the standard wedge as set forth hereinabove in the general disclosure of my invention. The A variant of Fig 7 is showing the arrangeaent considered from a direction perpendicular to the axis of the radiation path, the G variant is differing therefrom in so far that the said axis is turned around bf 90° whereas the 3 variant is showing the projection of the arrangement considered from behind the radiation source in the direction of the said axis. These projections are identical with the ones of Fig 8A,B,0 wiere the film images obtained in this arrangement are shown as sketches reduced to the important features, in the said film images, the intercept curves are representing spots of identical blackening.

Claims: Claims: 1. A method for producing the radiological /radiographic or radioscopic/ image of an object, preferably for use in the radiological testing of industrial materials, which comprises arranging the specimen to be tested /hereinaf¬ ter: test body/ in a certain spot of a test area /here¬ inafter: test spot/ in front of a means for detecting the radiological /X-ray, -^-ray, isotope radiation/ image and recording same on a film or displaying same on an image screen /hereinafter: radiation receiver/; transmitting radiation beams towards the said test spot, and evaluating the thus obtained image taking, if necessary, into consid¬ eration also the known properties of the test body, where¬ in the improvement consists in that a modifying body is arranged in the radiation path between the test body and the radiation receiver, the said modifying body consisting in a laminated thin layer package obtained by packing thin flat sheets /foils/ upon each other and being arranged in a manner that the axis of the radiation path is including an angle of 0° to 60° with the normal of the thin layer surface, preferably the said axis and the said normal lying collaterally with each other, and the substantial and geometrical features of the modifying body are in the course of evaluating the radiological image also taken into consideration. 2, A method as claimed in Claim 1 wherein a homogenuous compensating body /hereinafter: compensator/ is arranged in the radiation path between the radiation source and the radiation receiver, i. e. before or behind the said test body, the said compensator being cut askew and the oblique portion of its superficies is facing the radiation source and at the same time including an angle '^ /0< <90 0 / v/ith the normal of the axis of the radiation path, 3. A method as claimed in Claim 2 wherein a cylindrical body or a cylindrical pipe is tested and the compensator is OMPI arranged in a manner that the angle t be complying with the equation: tg -f = D'/ » wherein D> is the maximum length of the test body along the normal of the axis of the radiation path and L' is the maximum length of the path along which the radiation is passing through the coherent medium forming the test body. 4. A method as claimed in Claim 2 wherein a non-cylind- rical body is tested and the compensator is arranged in a manner that the angle be within the range: 30° -≤f 60°. 5. A modifying body foa\ use in radiological - preferably material - testing in order to influence the structure of the ray image, which comprises a package of three or more thin flat sheets each sheet having a practically homogenuos structure and a density equalling or - preferably - exceed¬ ing the density of the object to be tested, the said sheets being packed upon each other and integrated into a lamin- ated thin layer body by sticking, gumming, thermopressing, or the like. 6. A modifying body as claimed in Glai 5 wherein each of the said sheets is mounted on a carrier sheet and the laminated carrier sheets are integrated to form the said thin layer body. OMPI

Inventors: TELEKI PETER, TELEKI, PETER
Applicants: KOEZPONTI VALTO HITELBANK, KOEZPONTI VALTO- ES HITELBANK RT INNOVACIOS ALAP
Application year: 1983
Main classification: G01N23
IPC codes: G01N23