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Linear accelerator radiography

Domanus, J.; Hansen, J.

Publication date:1973

Document VersionPublisher's PDF, also known as Version of record

Link back to DTU Orbit

Citation (APA):Domanus, J., & Hansen, J. (1973). Linear accelerator radiography. Risø National Laboratory. Risø-M, No. 1599

A. E. K. Risø Risø-M-Li^ Title and author(s)

LINEAR ACCELERATOR RADIOGRAPHY

by

J. Domanus

and

Johnny Hansen

3o pages - f 12 tables + 68 illustrations

D a "

Dep?'tmcnt oi !ro p

Metallurgy f-p

Group's own registration .>jrrber(s)

A-173

Abstract

A description is given of the Risø lo MeV linear

accelerator, which was used for radiography of steel

(5o to 25o mm thick). Different X-ray film and inten­

sifying screen combinations were tested and charac­

teristic curves and exposure charts were computed.

X-ray film speed and contrast were calculated.

Radiographic image contrast and quality were investi­

gated and the best combination of X-ray film and screen

was chosen.

Conclusions were drawn about the possibility of

using the Risø accelerator for industrial radiography.

Copies to

Prof . A.R. Mac\ir.;.osh

Dr. F . J u u l

Dr. C F . .Jacobsen

M. Møller-Mads*..-;

Me ta l l u rgy Dept . (^o)

A c c e l e r a t o r Bep<-. (5)

Abstract to

Available on request from the Library of the Danish Atomic Energy Commission (Atomenergikommissionens Bibliotek), Risø, Roskilde, Denmark. Telephone: (03) 35 51 01, ext. 334, telex: 1*3116

I6BM 87 55o ©197 1

LTNBU ACCELERATOR

RADIOGRMBY

ty

J . Donanus

Elsinore Shipbuilding and Engineering Co., Ltd., Helsingør

and

Metallurgy Department. Banish Atonic Energy Commission,

Research Establishment Risø

and

Johnny Hansen

Accelerator Department, Danish Atonic Energy Commission,

Research Establishment Bise

March 1975

Work performed under contract between the Elsinore Shipbuilding

and Engineering Co., Ltd. and the Metallurgy Department of the

Danish Atomic Energy Commission, Research Establishment Rise.

- 2 -

CONTENTS

Page Introduction ............ 7

Description of the accelerator 7

2.1. The accelerator 7

2.2. Beam parameters 8

2.3« Description of the Bremsstrahlung converter ....... 9

X-ray film and intensifying screens 9

Exposure technique 11

Exposure conditions 11

Slotted steel wedge 12

Characteristic curves of X-ray films 13

7.1. Direct exposure 13

7.2. Exposure through steel 13

Intensification factors 1*+

Film speed and contrast 15

9.1. Film speed 15

9.2. Film contrast 18

Attenuation in steel 2o

Radiographic image contrast • 2o

Radiographic image quality 23

Film unsharpness • 26

Exposure charts 28

Summary of conclusions 29

References J>o

Figures 31

- 3 -

FIGURES Page

Fig. 1. Calculated lo MeV Bremsstrahlung spectrum for the

converter 31

Fig. 2. Intensity distribution in the X-ray beam 32

Fig. 3. Elements of the steel block 33

Fig. 4. Steel block after assembly 33

Fig. 5« Construction of the slotted steel wedge J>k

Fig. 6. Steel wedge in its full length 33

Fig. 7* Four slotted steel wedges 33

Fig. 8. Positioning of the slotted steel wedge between

the masking steel plates 36

Fig. 9. Do 37

Fig. lo. Characteristic curves (no filtration) for Kodak Microtex films 3d

Fig. 11. Characteristic curves (no filtration) for Structurix D2 films 39

Fig« 12. Characteristic curves (no filtration) for Structurix Dk films *K>

Fig. 13* Characteristic curves (no filtration) for GAF loo films *H

Fig. Ik, Characteristic curves (no filtration) for GAF 2co films ^2

Fig. 15. Characteristic curves (no filtration) for GAF ^00 films ^3

Fig. l6. Characteristic curves (no filtration) without intensifying screens *"

Fig. 17. Characteristic curves (no filtration) with 1 + 1 mm Pb screens • ^5

Fig. l8. Characteristic curves (no filtration) with 1.3 + 1.3 mm Pb screens ™

Fig. 19. Characteristic curves (no filtration) with 1.3 + 1.3 mm Cu screens ^7

Fig. 2o. Characteristic curves (through 5o-15o mm Fe) for Kodak Microtex films with 0.I5 + o,25 mm Pb screens ... ™

Fig. 21. Characteristic curves (through 5o-25o mm Fe) for Kodak Microtex films with 1 + 1 mm Pb screens ^9

Fig. 22. Characteristic curves (through 5o-15o mm Fe) for Kodak Microtex films with 1 + 1 mo Cu screens... 5°

Fig. 23. Characteristic curves (through 5°-25o ™" Fe) for Kodak Microtex films with SMP lol screens 51

- k -

Page

Fig. cik. Characteristic curves (through 5o-25o mm Fe) for Kodak Microtex films with SMP ?ol screens ^

Fig. 25. Characteristic curves (through 5o-15o mm Fe) for Structurix D2 films with 0.I5 + o.25 mm Pb ocrc-cr;.- ',-;

Fig. 26. Characteristic curves (through 5°-15o mm Fe) for Structurix D2 films with 1 + 1 mm Cu screens r-~l,

Fig. 27. Characteristic curves (through 5°-15° mm Fe) for Structurix Bk films with 0.I5 + o.25 mm Pb screens ..... ;..

Fig. 28. Characteristic curves (through 5o-15o mm Fe) for

Structurix D*f films with 1 + 1mm Cu screens %

Fig. 29. Attenuation curve in steel 57

Fig. 3°. Visibility of slotted wedge on Kodak M films with 1 + 1 mm Pb screens 58

Fig. 31. Visibility of slotted wedge on Kodak M films with SMP lol screens 59

Fig. 32. Visibility of slotted wedge on Kodak M films with SMP 3ol screens 60

Fig. 33« Visibility of slotted wedge on Kodak M films with 0.I5 + 0.23 mm Pb screens 61

Fig. 3 » Visibility of slotted wedge on Kodak M films with 1 + 1 mm Cu screens 62

Fig. 35« Visibility of slotted wedge on Structurix D2 films with 0.I5 + 0.25 mm Pb screens 63

Fig. 36. Visibility of slotted wedge on Structurix D2 films with 1 + 1 mm Cu screens 64

Fig. 37. Visibility of slotted wedge on Structurix D^ films with 0.I5 + o«25 mm Pb screens 65

Fig. 38. Visibility of slotted wedge on Structurix Dh films

with 1 + 1 mm Cu screens 66

Fig. 39» Scanning densitometer 67

Fig. ho. Per cent IQI sensitivity 68

Fig. kl. IQI sensitivities for 1 + 1 mm Pb screens • 69

Fig. kZ. Do 7o

Fig. V3. IQI sensitivities for 1.5 + 1.5 w® P° screens 71

Fig. kk. Do 72

Fig. k$. Do. 73

Fig. h6. Do 7^

Fig . hj. IQI s e n s i t i v i t i e s for 1.5 + 1.5 mm Cu screens 75 F ig . kS, IQI s e n s i t i v i t i e s for d i f fe ren t f i lm-screen-

combinations 76

F i g . '+9. Geometric unsharpness of the radiographic image 77

: :ife

i'i£;. ljo. Exposure charts for Kodak M and o. 15 + o..''5 •:;?:< Pb

screer.s 75

Fir. ;>L. Exposure charts for Structurix D2 and Lk with

0.I5 + 0.25 mm Pb screens 7 )

Kir. '-.'. Comparison of exposure charts from figs. 5o and 51 80

Vir.. '• '•. Exposure charts for Kodak M and 1 + 1 mm Pb screens .... Si

Fif;. lA. Exposure charts for Structurix D2 and Dk with 1 + 1 mm Pb screens 3c

Fig. 55. Exposure charts for GAF films with 1 + 1 mm Pb screens 83

Fig. 56. Comparison of exposure charts from figs. 53-55 Sh

Fig. 57. Exposure charts for Kodak M with 1.5 + 1.5 mm Pb screens 85

Fig. 58« Exposure charts for Structurix D2 and D^ with 1.5 + 1.5 mm Pb screens 36

Fig. 59« Exposure charts for GAF films with 1.5 + 1»5 mm Pb screens 8?

Fig. 60. Comparison of exposure charts from figs. 57-59 ••••••••• 88

Fig. 61. Exposure charts for Kodak M witn 1 + 1 mm Cu screens 39

Fig. 62. Exposure charts for Structurix D2 and Dk with

1 + 1 mm Cu screens 9°

Fig. 63. Comparison of exposure charts from figs. 61-62 91

Fig. 6k. Exposure charts for Kodak M with 1.5 + 1.5 mm Cu screens 92

Fig. 65. Exposure charts for Structurix D2 and D*+ with 1.5 + 1.5 mm Cu screens 95

Fig. 66. Exposure charts for GAF films with 1.5 + 1.5 mm Cu

screens 9^

Fig. 67. Comparison of exposure charts from figs. 64-66 95

Fig. 68. Exposure charts for Kodak M with 1 + 1 mm Pb, SMP lol, and SMP 3ol screens 96

- 6 -

TABLES

Page

Table 1, X-ray films and intensifying screens lo

Table 2. Thicknesses of the slotted steel wedge 12

Table 3* Intensification factors Ik

Table k. Relative film speeds (exposed without steel

filtration) 16

Table 5» Relative film speeds (exposed through steel) ........ 17

Table 6. Relative intensification factors 18

Table 7. Average gradients of X- ray films 19

Table 8. Thickness regions in mm of Fe of slot

visibility on radiographs 21 Table 9. Maximum density differences for different

per cent slot depths 22

Table lo. Wire diameters of the ISO IQI's 23

Table 11. Film densities during radiographic image

quality investigations , 2k Table 12. Film unsharpness 26

- 7 -

1. INTRODUCTION

Since i960 a lo MeV Varian Model V-77oo linear accelerator has been

used at Bisø for radiation chemistry, dosimetry and sterilization purposes.

It was decided to test the possibility of using this accelerator to per­

form radiography of thick steel castings.

The purpose of this investigation was to establish a correct exposure

technique and to test the influence of different exposure factors on radio­

graphic image quality.

In the first instance different X-ray film bands and intensifying

screens were tested to determine characteristic curves and exposure charts

for steel from 5o to 25o mm. From these curves, intensification factors

for different film-screen-combinations were calculated.

Next, for different film-screen-combinations optimum radiographic

image contrast and image quality were investigated. For that purpose a

special slotted wedge penetrometer was used as well as ISO wire image

quality indicators.

In the future other exposure factors (e.g. focus size, and focus film

distance, and scattered radiation) will be investigated as well.

2. DESCRIPTION OF THE ACCELERATOR

2.1. The accelerator

The Risø accelerator is a two-section S-band electron linear accele­

rator with a maximum average output power of approx. 4.5 kW at lo MeV.

The linear accelerator is essentially a pulsed source of high energy elec­

trons, with pulse lengths adjustable from o.2f> to 7 lis at peak pulse cur­

rents up to max. 32o mA. At a pulse lenjtl* of 7 p.s the maximum pulse cur­

rent is 21o mA. The pulse repetition rate is stepwise variable from a

single pulse to 3°° pulses per second. The pulse shape is fairly rectan­

gular with a rise time of the order of o.l (J.s.

The two accelerator guides, each 1 ra long, are horizontally placed,

and the electron beam can be directed through A straight-ahead window or

down through a 9o bending magnet and a scanning system for irradiation of

products carried on a conveyor. For the conversion of the electron beam

into X-rays, a Bremsstrahlung converter is placed in front of the straight-

ahead window in the beam centre line.

- 8 -

The electron beaa inside the accelerator has a diaæter of about k mm

and a divergence of a few milliradians before it leaTes the vacuum system.

Scattering occurs at the 0.I5 an aluminium foil exit window, and the emerg­

ing beaa is auch aore divergent. Within a distance of 50 ca froa the exit

window the electron beaa in air has an alaost linear divergence. At 50 ca

its intensity decreases 5o)f froa the centre to the edge of a 32 aa diaaeter

field.

2.2. Beaa paraaeters

To keep the radiation conditions as stable as possible beaa paraaeters

such as bear energy and average beaa current aust be controlled. In the

straight-ahead aode of the accelerator there are no possibilities of con­

tinuous control of electron energy during irradiation. This aeans that

after the initial warm-up period, the aachine has to be checked a few tines

during the day because of further, gradual stabilisation or fading of vari­

ous circuits«

The energy and current paraaeters deteraine the dose distribution

throughout the saaple as well as the average dose rate. To obtain repro­

ducible radiation conditions froa one irradiation period to another, the

dose rate at a given position is seasured by aeans of a dosiaeter.

A relative aeasure of the electron energy is readily available as the

accelerator is fitted with a bending aagnet, and the aagnet current needed

to bend the beaa through the 9o angle is proportional to the electron

energy. Initial calibration of the bending aagnet has shown that it is

possible to reproduce the aain energy coaponent with an accuracy of about

l£. Measurement« of the current versus energy have shown that at lo MeV

6oj£ of the peak bean current is contained within an energy band of lojf.

An absolute Beasureaent of the beaa current can be aade by having the

electrons absorbed in a aluainiua or graphite plate thick enough to absorb

all the electrons entering it and by aeasuring the resulting current flow*

ing to ground-potential. (The backscatter correction is less than 2% for

aluminium at lo MeV). A continuous aeasure of the peak pulse current can

be made by means of a non-intercept monitor consisting of a toroidal pick­

up coil, which is mounted around the beaa centre line. The average cur­

rent, determined froa the peak pulse current, the pulse length and the

pulr;e repetition rate, nay change up to 15&S in the course of one day if no

r '>-.'],ju:;i,mentc are made. For the measurements described in this report

!:''iU'.M. -Urt.;: nnd stops of the accelerator have been required, which may

- 9 -

implicate dose variations of no more than lo%«

2*3* Description of the Breasstrahlung converter

The converter consists of three sections: a tungsten plate, a

cooling water slab, and a stainless steel backing plate. The X-ray pho­

tons are produced in the tungsten target by the stopping of the high

energy electrons, while the water slab and the backing plate, which are

located downstream froa the tungsten disc, act as an electron filter as

well as a hardener of the X-ray spectrin. Fig. 1 shows a calculated

Breasstrahlung spectrum for the converter«

As most of the bean power is stopped in the tungsten target, this

causes a heavy thermal load, i.e. the permissible •jp*w"i beam diaaeter

on the target is deterained by the bean power and the mechanical proper­

ties of the material. From calculations on the converter target a minimum

beam diaaeter of 2o mm was found necessary, lest the tungsten disc should

not be damaged when the accelerator is operated at full output power«

From measurements on the electron beaa, showing the beaa divergence in air,

a distance of 2o ca from the accelerator exit window to the converter was

chosen. At this distance the beam diameter containing 8ojt of the total

electron current has increased to approximately 25 aa.

At a distance of 5o ca froa the converter the forward angular inten­

sity of the X-ray beam has been measured as absorbed dose rate by means of

"Super-Fricke" dosimeters « The results are shown in fig. 2 as the

polar coordinates of the rate of the relative absorbed dose in water as a

function of the angle. In the practical application, the dose rate in any

given geometry has to be measured. The saaple was positioned at a dis­

tance of 2 a from the converter in the beaa centre line and the dose rate

in water has been measured to o*2 Krad/h.

3- X-RAY FX1K3 AND InTENSIFnNS SCBEEHS

Kodak Microtex, Agfa-Gevaert Structurix D2 and D4, and GAF loo, 2oo

and 4oo X-ray films were used.

Metal intensifying screens: lead Co, 15 + o.25; 1 + 1 and 1.5 + 1.5

am) i copper ( 1 + 1 and 1.5 + 1*5 am) as well as fluorometalic Kyokko SMP

lol and SMP 3ol screens were used*

Table 1 shows what combinations of films and screens were used in

the various stages of the investigation.

- 11 -

*. EXPOSURE TECHNIQUE

The tunesten target was placed at a distance of 2o n fro« the elec­

tron exit window of the accelerator, and X-ray films (in cassettes) were

positioned at 2 m distance froa the target. The distance between the filn

and a concrete wall of the accelerator cell was about 1 ••

In front of the film, steel plates (or eteel penetraæters of differ­

ent thicknesses froa 5° to £5<> ••) were placed«

The accelerator was run at lo MeV with an electron current of loo or

2oo sA. The pulse length was 7 *LS. The pulse repetition rate was either

57 or Joo pulses per second«

For short exposures (no steel filtration) 2oo aA and 3oo pps were

used whereas for longer exposures loo aft and 37 PP» have to be applied to

prevent overheating of the accelerator exit window. The end results ere

all relative to a loo aA electron current.

Changes in exposure tiae were aade by changing the nuaber of pulses,

keeping all other paraaeters constant.

5. EXPQSUHE CONDITIONS

X-ray films in plastic cassettes, froa which air was evacuated to en­

sure better contact between fila and screens, were exposed either directly

to X-radiation cr through adequate filtration of steel«

For filtration purposes steel plates were used, ranging froa 5© aa

( one plate) up to 25o aa (five plates). Each plate (2oo x 3oo an) was

surrounded by additional Masking steel plates: froa the bottoa and top by

loo x 5oo on plates, from the sides by 15o x >x> •• plates« Thus a steel

block was formed having the surface of 5oo x 5oo aa and the thicknesses

from 5o to 25o as. A U the eleaents used for the construction of such a

block are seen on fig. 3* To keep the whole construction together a steel

frame was used (at left of fig. 3)* Fig. h shows the whole assembly.

In front of the steel block wire type iaage quality indicators (IQI)

were placed during the investigation of the radiographic image quality.

- 12 -

6. SLOTTED STEEL WEDGE

For the investigation of radiographic contrast sensitivity a slotted

steel wedge was used. The wedge was fabricated from a 25o mm thick steel

plate, 12oo mm long. In this plate rectangular grooves were machined,

having the following per cent depths: 0,25; 0.5; l.o; 2.o and 5.o. The

grooves were lo mm wide and spaced 2o mm from each other with a distance

of 35 mm from the wedge edges (see fig. 5)» At the top the wedge was 5o

mm thick and at the bottom 25o mm thick* At a distance of 17.5 mm from

the edge 11 holes (5 mm in diameter and loo mm deep) were drilled at both

sides of the wedge at intervals of 5o mm. These holes served as distance

calibration points for the radiographs. Through the black spots, which

these holes produced on the radiographs, parallel lines were drawn corre­

sponding to the thickness of the step wedge (see table 2).

After machining the grooves in the steel wedge, the wedge was cut

into four pieces each of a length of 3oo mm (figs. 6 and 7). The thick­

nesses of the four steel wedges are: 5o-loo; loo-l^o; 15o-2oo and 2oo-

25o mm.

Table 2. Thicknesses of the slotted steel wedge (mm)

Thickness range-mm

Calibration hole

Distance from

wedge edge-cm

2.5

5.0

7.5

10.0

12.5

15.0

17.5

20.0

22.5

25.0

27.5

No.

1

2

3

it

5

6

7

8

9

10

11

50-100

54.2

58.3

62.5

66.6

70.8

75.0

79.1

83.3

87-5

91.6

95-8

100-150

104.2

108.3

112.5

116.6

170.8

125.0

129.1

133-3

137-5

141.6

145.8

150-200

154.2

158.3

162.5

166.6

170.8

175-0

179-1

183.3

187.5

191-6

195-8

200-250

204.2

208.3

212.5

216.6

220.8

225.0

229.1

233.3

237-5

241.6

245.8

- 1 3 -

Each slotted steel wedge was positioned between the masking steel

plates as shown on figs. 8 and 9. The bottom and side masking plates had

a thickness corresponding to the bottom thickness of the wedge, whereas

the top masking plate had a thickness equal to the top thickness of the

wedge.

The slotted steel wedge was used as a defectometer for the determina­

tion of the radiographic image contrast* The use of such a defectometer

was previously described for X-rays and for gammarays . It was also

used for a similar investigation in Co ° radiography with satisfactory

results.

7. CHARACTERISTIC CURVES OF X-RAT FIIMS

Characteristic curves were computed for different X-ray film and in­

tensifying screen combinations (as shown in table 1) and for exposures

with and without different steel filtration.

7.1. Direct exposure

Kodak Microtex, Agfa-Gevaert Structurix 02 and D4, GAF loo, 2oo and

4oo X-ray films with and without l.o + l.o and 1.5 + 1.5 mm lead and 1.5 +

1.5 mm copper screens were directly exposed to the accelerator X-rays

(without steel filtration) (table 1-marked o).

Film densities up to 5.0 were read on a "Quanta log" Macbeth trans­

mission densitometer* The characteristic curves were drawn for different

exposures, given as number of pulses* They are presented on figs, lo to

15* On those curves thicknesses of the intensifying screens are given

("o" means "no screens").

Figures 16 to 19 give a comparison of characteristic curves of various

films for the same intensifying screens.

7.2. Exposure through steel

Kodak Microtex films with 0.15 + o.25 and 1 + l m m P b , 1 + l m m C u

metal intensifying screens and SMP lol and SMP 3ol fluorometalic screens

as well as Agfa-Gevaert Structurix D2 and D4 films with 0.15 + o.25 mm Fb

and 1 + 1 mm Cu-screens were exposed through steel wedges of various thick­

nesses (see table 1). From the radiographs of steel wedges density read­

ings were made at different wedge thicknesses (as shown in table 2), and

- 1 4 -

from these readings characteristic curves were computed as shown on figs.

2o to 28. On these figures wedge thickness ranges are marked, and for

each range 11 curves are given. Each curve corresponds to the thickness

specified in table 2 (first curve to the left corresponds to line No. 1,

last curve to the right corresponds to line No. 11). Because of overlap­

ping less than 11 curves are reproduced for a given thickness range. On

some curves there is a lack of continuity and some curves are displaced in

different pulse number regions. This was due to the fact that during a

series of exposures of the wedge the required density range could not be

reached and the exposures were repeated later. This was connected with

another setting of the accelerator parameters and it was difficult to ob­

tain exactly the same dose per pulse in the X-ray beam. Therefore, for

the same number of pulses different doses of radiation were absorbed by

the film (for explanation see section 2).

8. INTENSIFICATION FACTORS

From the characteristic curves shown on figs, lo to 15 intensification

factors for lead and copper screens were calculated (as the relation be­

tween number of pulses necessary to give the same film density for the

film exposed with and without intensifying screens).

Table 3. gives the results of these calculations.

Table 3- Intensification factors

Film

Kodak Microtex

S t n W i x D2

GAF 100

200

'too

Intensifying screens

1 + 1 mm Pb

5.10

5.*0

5.01

5.97

5.13

k.29

1.5 + 1.5 mm Pb

hA9

4.71

3 . «

5.89

3.92

3.56

1.5 + 1.5 ™ Cu

1.6*

1.69

1.83

2.11

3-39

2.00

- 15 -

In computing table 3 intensification factors were first calculated

for the following densities: o.5; l.o; 1*5; 2.o; 2*5; 3.0; 3-5 and *f.o.

Next, for each film-screen-combination, mean values of intensification

factors for all those densities were calculated; these valves are given

in table 3»

As can be seen, the best intensification is obtained with 1 + 1 mm

lead screens. Copper screens give much poorer intensification than lead

of the same thickness.

9. FIW SPEED AND CONTRAST

Speed and contrast of different X-ray film-and-screen combinations

were determined using the American Standard Method for the Sensitometry of

Industrial X-ray Films for Energies up to 3 Million Electron Volt.

9.1. Film speed

According to this standard X-ray film speed i s determined for the

density of 1.5 above the base and fog density. The speed of the film i s

taken as the reciprocal of exposure, measured in roentgens, necessary to

produce a density of 1.5-

In the present investigation only relative film speed densities were

determined and therefore they are given in arbitrary units.

Table 4. gives relative speeds (speed of Kodak Microtex film taken as

l .o) of X-ray films, calculated for direct exposures done without steel

filtration.

- 16 -

Table k. Relative film speeds (exposed without steel filtration)

Film

M

D2

D4

100

200

400

N

D2

D4

100

200

400

Intensifying screens

No screens

1.00

0.44

1.56

0.39

0-70

1.62

1.00

0.44

1.56

0.39

0.70

1.62

Lead screens

1+1 am

1.00

0.46

1.53

0.46

0.70

1.36

5.10

2.37

7.81

2.32

3-59

6.95

1.5+1.5 "•

1.00

0.46

1.20

0.51

0.61

1.28

4.43 2.07

5.39 2.30

2.74

5.77

Copper screens

1.5 + 1.5 ••

1.00

0.45

1.74

0.50

1.45

1.97

1.64

0.74

2.85

0.82

2.37 3.24

For X-ray films exposed through different thicknesses of steel

relative speeds have been calculated for density 1.5 in the middle of

each wedge thickness (i.e. behind 75i 125, 175 and 225 •» of steel).

The results of these calculations are shown in table 5«

- 17 -

From tables 3 and 5» the following relative intensification factors

can be computed in relation to films exposed with 1 + 1 mm Pb screens

(relative intensification factor l.o).

Table 5. Relative film speeds (exposed through steel)

Intensifying

screens

0.15+0.25Pb

1 + 1 Pb

I 4 I C 1

SKP 101

SMP 301

Steel

thickness

75

125

75

125

175

225

75

125

75

125

175

225

75

125

175

225

Film

H

0.66

1.33

1.0

1.0

1.0

1.0

0.41

0.85

1.55 1.44

1.66

2.00

2.66

2.40

2.56

3.33

D2

0.17

0.35

0.10

0.24

D4

1.07

2.60

0.68

1.30

-IB -

Table 6. Relative intensification factors

Film

Kodak Mi-

c r o t e x

S t r u c t u -

r i x B2

» D4

GAP 100

200

WO

S t e e l f i l t r a t i o n - • •

0 50-150

I n t e n s i f y i n g s c r e e n s

1.5+1-5P0

0 .88

0 .87

0 .69

0 . 8 6

0 .76

0 . 8 3

1.5+1.5CU

0 . 3 2

0 . 3 1

0 . 3 6

0 . 3 5

0 . 6 6

0 . 4 6

0.15+0.25PD

0 . 9 9

1+1 Cu

O.63

50-250

SHP 101

1.66

SHF 301

2 .74

In the above table mean values of film speeds were taken from table 5

(for the whole range of steel filtration).

9.2. Film contrast

R(W According to ASA standard PH 2.8 " the average film gradient is

defined as the slope of the straight line drawn on the characteristic

curve between the points corresponding to densities of o.5 and 2.5.

The average gradient : 2.0 log E 2 - log ^

where

E is the exposure corresponding to a density of 2*5, E. is the exposure

corresponding to a density of 0.5.

Following the above formula average gradients for different X-ray

film and screen combinations were computed and are shown in table 7.

- 19 -

Table 7. Average gradients of X-ray films

I n t e n s i ­

fy ing

s c r e e n s

0

0.15+0.25P1

1 t 1 Pb

I . 5 + I . 5 P 0

1 + 1 Cu

1.5+1.5CU

SKP 101

SHP 301

S t e e l

t h i c k ­

nes s

0

75

125

0

75

125

175

225

0

75

125

0

75 125

175

225

75

125

175

225

F i l « brand

Kodak

Hicrotex

6 . 9 *

5.3O

l | . 5 *

6 . 9 *

! i .76

1..85

5 -76

<i.30

7 . 1 1

3 -95

<t.60

5 . 8 3

5 . 8 8

5 . 8 8

5 . 6 3

5 . 0 6

5 . 6 1

5 A 6

5 .66

<t.70

S t r u c t u r i x

D2

5 -39

k.Zl

3-77

6 . 3 3

6 . 0 0

<t.82

4 . 8 2

5-98

1*

6 . 6 6

1.. 68

7 -60

6 . 9 7

"..56

4 . 7 1

5 . 0 2

GAF

100

7.2<>

6 . 7 3

6 . 7 3

6 . 2 9

200

5 . 3 3

5 . 6 8

6 . 1 1

5.6*

".00

6 .89

5 .97

7 . 3 5

5 .26

The average gradient was calculated for E, and £, corresponding to

densities 3.5 and 1.5 as most of the characteristic curves did not have

densities less than o*5*

lo. ATTENUATION IN STEEL

Attenuation of X-ray radiation from the accelerator nas measured

using "Super-Iricke" dosimeters. For that purpose the saae steel plates

were used as shown on fig. 4. The attenuation curve obtained fro« these

measurements is shown on fig. 29.

There per cent attenuation is given as well as the attenuation factor

k (reciprocal of the attenuation).

11. RADIOGRAPHIC HUGE CONTRAST

For X-ray films and intensifying screens and steel thickness ranges,

shown in table 1, radiographs of a slotted steel wedge were made. For

each slotted wedge (5o-loo; I00-I50; 150-200 and 2oo-25o mm) films were

exposed with different number of pulses so as to reach film densities be­

tween 2 and 3 at both ends of the wedge. A U films were then developed in

an automatic film processing machine and film densities (up to 5) were

read on a 'IJuanta Log" Macbeth transmission densitometer.

The radiographs were read by two observers, and only such readings

were taken into account where both observers could see the same slot on

the radiograph. The radiograph of each slotted wedge was read along 11

lines, drawn through images of the holes drilled in the wedge. Thus it

was possible to assess the radiographs at different wedge depths (all

together V 1 11 = W depths, as shown in table 2).

From the assessment of visibility of slots of different depth on

wedge radiographs, diagrams were prepared, showing thickness ranges, in

which the particular slots could be seen on the radiographs, in function

of exposure (number of pulses) (similar to curves given in (<t) and ( 5 ) ) .

These diagrams are shown on figures 3o to 38. On these figures areas of

visibility of the five slots of different per cent depth are given.

From these diagrams, the following conclusions can be drawn. The

0.25a! slot was sometimes visible only on Kodak Mdcrotex film with 1 + 1 mm

Pb screens in the range from 50 to 2oo mm of steel. The visibility of the

deeper slots is given in table 8 for different steel thickness regions.

- 21 -

Table 8. Thickness regions in am of Fe of slot visibility on radiographs

Film and Screen

Combination

M 1+1 Pb

M SHP 101

K S MP 301

w. 0 . 1 5 + 0 . 2 5 Pb

M 1+1 Cu

D2 0 . 1 5 + 0 . 2 5 Pb

D2 1+1 Cu

D4 0 . 1 5 + 0 . 2 5 Pb

D4 1+1 Cu

Per Cent S l o t Depth

0 . 5

54-21(6

54-229

54-225

L04-146

L07-146

104-11*6

L04-146

L04-141

LOlt-llH

1

III

5 4 - 1 «

54-11*6

54-146

54-146

54-146

54-146

2 III 54-146

54-146

54-146

54-146

54-146

54-146

5

III

54-146

54-146

54-146

54-146

54-146

54-146

From the diagrams (figs. 30 to 38) one can see that for increasing

slot depth the latitude of exposure increases for the same slot depth

visibility.

Results quoted in table 8 cannot give a final answer to the question

which X-ray film and screen combination will give the best radiographic

image contrast. Therefore the radiographs of the slotted wedges were

further investigated by means of a scanning densitometer (seen on fig. 39).

Bach radiograph was scanned along U lines on each radiograph (at different

wedge thicknesses - see table 2) and densitometer readings were recorded

by a paper chart recorder. From the results obtained during these trans­

verse scans absolute and relative increases in film densities could be

measured and calculated for different per cent depths of the slots. The

results of the above are given in table 9.

From table 9 the following conclusions can be drawn. Kodak Microtex

film with 1 + 1 mm Pb screens gives the best radiographic image contrast.

especially in the region of greater steel thicknesses (above 15o mm),

where the application of accelerator radiography presents most advantages.

The fluorometalic intensifying screens give very good results (even better

than lead screens) in the region up to 15o mm Fe. Above this thickness

they are poorer than lead.

lA

d

* f t

Aj

lA

s <

4

a

o <

a <

a

a <

a

<

<

o

ram

Fe

!

* L

r A l A O KN C*- AJ l A r H

O W r l r t

n - a - t y AJ O O O O

o o o d

rA i A t y vo 4 0 1 0 0

H AJ r-t Aj

O rH H H

J - O f t I O

H t y fy AJ

0.03

0.

03

0.05

0.

04

-d- lA-d-NC rH VO H O

AJ H ry AJ

\ f l f f l f t J J -O ry rA-3-

ry rA j - i A

IA AJ O ON Cv O rH O O

d d d d AJ t A O - d - , riOrlO

H O - * - * O ONVO n j

IA Cv ON CO

IA IAONVO O H H H

6 6 6 o Cv O O IA O VO O ON

r H r l f t J H

50-1

00

100-

150

150-

100

20

0-25

0

1+1

Pb

s

rH O ON CV fy rH 00 IV

ri ri ri O

IA Al t A - * H - * rH O O O O

0 0 d 0

O v o l A O l A O O O

(A ri AJ AJ

- * O OOO I A j - ON CV

Al A l rH ri

ON lAVO A l

O O O O

O O O O

-± ry oco vo 0 0 0

rA ry r A H

O - J - i A ON H Al Cv ru

i A rA ry r y

-a- i A r A i A r A - a -O O O O

d d d d 00 ONco AJ

O O O O

H H H AJ

-a- rno cv V0 H v O J -

I A 0 0 C v \ 0 CO

VO IA IA AJ O H H rH

O O O O

l A O l A t O O ON O 0>

H H Al H

50-1

00

100-

150

15

0-20

0

200-

250

CO H

•s

OO CvvO I A -a- H O ON

ri ri ri ri

H V O I A l A I A r H - a -

0 0 0 0

d d d d CO ØN-vo vo

0 o-a- 0 AJ l A r H AT

AJCO AJ fjs

AJ O ry j -

r y I A H H

\ 0 \ 0 l A H - a r - a -O H O O

do d d J - O AJOO H IAO0 O

AJ K \ r A r A

H J - VD AJ

vo -a - 0 0

AJ i A r A AJ

0.0

56

0.11

0.

115

0.06

-a- cv cv cv

H H N O

ry i A I A I A

H C O O M A lA-a-oO Cv

VO00 Cv i A

VO IA1ACO O H rH O

O O O O

•ACvoO AJ O IACO IA

ri ri ri r-\

50-1

00

100-

150

15

0-20

0

200-

250

£3

3:

0.82

0.

77

O.0

3 0.

019

3.62

2.

48

1.22

1.7

1

* * 6 6

3.68

2.

57

1.5

4

2.0

5 0.1

6

0.04

I.

07

2.08

3.0

3

5.27

0.

03

0.1

05

1.0

3

1.9

9

50-1

00

100-

150

+ .0 p*

H o j

d d

X

0.8

97

0.9

9 0.0

11

0.0

1

1.20

1.

04

1.42

1.

72

0.0

38

0

.04

3

2.71

2

.47

2.33

2

.94

0.0

38

0.0

88

1.

62

2.96

4.

57

7.1

9

0.0

95

0

.20

5

2.08

2.

85

50-1

00

100-

150

1+1

Cu

s:

0.6

9 0.

67

0.01

7 0.

010

2.37

1.5

6

1.10

2.

17

0.0

2 0.

07

1.77

3.

06

1.87

2.

40

0.0

33

0.

07

1.76

3.

04

3.99

6.

53

0.09

0.1

9

2.25

2.9

1

50-1

00

100-

150

0.1

5 +

0.

25 P

b

Od

Q

0.66

1.

77

0.01

8

0.01

9 2.

68

1.2

1

1.50

2.

30

0.0

57

0

.02

9 3.

72

1.24

1.

81

3.44

00 o j v o - d -O 0

od

3.7

9

1.24

3.3

3

6.99

0.0

7

0.0

86

2.

17

1.22

50

-100

10

0-15

0

1+1

Cu

1

o j

AA 66

0.01

7 0

.00

8

3.26

1.

64

0.94

1.

28

0.0

2 0

.04

6

o j \ o

OJ K\

1.6

3

1.94

0.

021

0.06

t N 0 -OJ O

00 o j C^ 0J

0.08

0.

08

2.1

3

1.6

3

50-1

00

100-

150

0.1

5 +

0.

25 P

b

VOVO

O O

0.01

3 0.

016

1.86

2.

50

1.23

1.

98

0.0

36

0.0

5 2.

90

2.54

^ 3 o O ^

0.0

75

0.0

35

2.

88

1.10

5.

06

8.5

1

0.11

0.

09

2.23

1.

10

50-1

00

100-

150

1+1

Cu

- 2 3 -

Another advantage of the flour ran tul i c screens i s the shortening of exposure tine* In comparison with the 1 + 1 am Pb screens exposure can be cut down to 5o< with SMP lo l and to 330* with SMP 3ol screens.

12. EADICGRAWIC DUGE QUAIJTT

Hie assessment of the radiographic iJBage quality was done by the ISO wire IQI's. For that purpose steel wire 1IS07 and 6IS012 IQI's were used having the following wire diameters.

Table 1 a Wire diameters of the ISO IQI's

IQI

1IS07

IQI

61S012

Wire number Wire diaaeter-mm

Vire number

Wire diameter-ma

1

3.20

6

2

2.50

7

1.00 0.80

j

2.00

8

0.63

4

1.60

9

0.50

5 1.25

10

0.40

6 1.00

11

0.32

7

0.80

12

0.25

Fig. ito gives the per cent IQI sensitivity for steel thicknessee

from 50 to 25o BID for IQI's from table l o .

The above mentioned indicators were placed in front of the steel plates (on the source side) of different thicknesses, and vires of minim« diameter seen on the radiographs were read by two observers, and only such readings were taken into account where both observers could see the same wire.

The IQI sensitivity was checked several times using different X-ray film and screen combinations« During these checks different film den­s i t ies were obtained. The results are shown on figs, kl to W*

Table 11 gives film densities obtained during these investigations.

- 24 -

Table 11. Film densities during radiographic image quality investigations

S t e e l t h i c k n e s s - mm [ 50

Fi lm

GAF 100

GAF 300

GAF 400

D 2

D 4

H

GAF 100

GAF 200

GAF 400

D 2

D 4

M

GAF 100

GAF 200

GAF 400

D 2

D 4

H

GAF 100

GAF 200

GAF 400

D 2

D 4

M

S c r e e n s

1+1 Pb

1+1 Pb

1.5+1-5 PI

1 .5+1-5 PI

F ig .No

41

42

43

44

1 .86

2 . 2 7

2 . 7 6

2 . 6 8

1 .30

1 .32

1 .25

3 . 2 2

1 .40

1 .75

1 .45

i . 8 o

i . 8 o

2 . 1 5

1 .75

1.96

2 . 1 4

5 .07

2 . 4 1

100

1.82

2 . 1 7

2 .62

2 . 3 5

1.24

1.34

1.19

2 . 8 4

1 .33

1.50

1 .45

1 .80

2 . 0 0

1.95

1 .95

1.96

2 . 0 7

3 .38

2 .16

150

1.79

1.82

2 . 2 8

1.52

1 .59

0 . 9 5

2 . 7 4

1 .48

1 .50

1 .75

1 .65

2 . 0 0

2 . 1 5

1 .9

2 . 5 0

2 . 8 7

2 .34

200

2 . 2 9

2 - 3 5

3 . 0 4

1 .58

1 .48

0 . 7 7

2 . 4 1

1 .38

1 .55

2 . 0 0

1 .80

2 . 1 5

2 . 4 0

2 . 2 0

2 . 3 7

2 . 7 2

2 . 8 2

250

3 .59

3-48

4 . 8 6

1 .30

1-34

0 . 9 1

2 . 42

1.36 *

1 .80

1 .80

2 . 2 0

2 . 5 0

2 . 3 0

2 . 4 0

4 . 2 9

4 . 3 4

5 .94

- 25 -

Table 11 continued

S t e e l t h i c k n e s s - mm

Fi lm

GAF 100

GAF 200

GAF 400

D 2

D 4

M

GAF 100

GAF 200

GAF 400

D 2

D 4

H

GAF 100

GAF 200

GAF 400

D 2

D 4

K

D 2

D 4

H

M

D 2

D 4

S c r e e n s

1 . 5 + 1 . 5 Pb

1 . 5 + 1 . 5 Pb

1 .5+1 .5 Cu

F i g . No.

45

46

47

0 .15+0 .25Pb 48

1+1 Pb

1 . 5 + 1 . 5 Pb

1+1 Cu

1 .5+1 .5 Cu

SHP 101

SHP 301

1 + 1 Cu

48

48

50

1 .30

1 .84

2 . 4 2

4 . 9 4

2 . 0 3

1 .75

1 .45

1.84

2 . 4 2

2 . 1 5

2 . 0 3

2 . 4 8

2 . 6 9

2 . 1 9

3 - 3 3

1.92

2 . 4 5

4 . 3 8

> 5 . 0 0

4 . 8 0

3 . 5 0

4 . 1 7

> 5 . 0 0

> 5 . 0 0

4 . 2 5

4 . 0 0

4 . 5 2

4 . 6 8

100

1.38

1 .82

1 .21

3 . 1 0

1.56

1 .50

1 .45

1.82

2 . 0 0

1-95

1 .95

2 . 8 8

3 . 6 8

1 .85

2 . 8 1

3 . 8 0

3 . 1 6

4 . 1 2

4 . 3 8

4 . 1 8

3 .16

3 -70

4 . 3 5

4 . 2 2

4 . 2 5

3 . 1 7

4 . 0 0

3 -90

150

1 .50

1 .80

1 .23

3 . 5 2

1.36

1 .50

1 .75

1 .80

2 . 0 0

2 . 1 5

1 .90

2 . 8 8

3 -71

3 . 1 4

2 . 6 7

3 . 3 0

2 . 5 0

4 . 4 7

4 . 7 2

3 . 7 3

2 . 5 8

3 - 4 7

3 .56

3 -50

2 . 4 5

4 . 0 0

3 . 5 0

4.38

200

1 .65

1.64

0 .94

2 . 8 8

1.52

1 .65

2 . 0 0

1.80

2 . 1 5

2 . 4 0

2 . 2

2 . 3 8

3 .24

2 . 5 6

2 . 2 0

2 . 9 0

2 . 4 3

4 . 2 5

2 .4 2

4 . 6 4

3 . 3 0

5.14

2 . 4 3

2 . 8 3

250

1.08

1.39

1.07

2 .64

1.28

1.80

1.80

2 .26

2 . 5 0

2 . 6 4

2 . 4

2 .54

4 . 3 0

2 . 9 6

2 . 8 3

3.6O

3-32

> 5 . 0 0

2 . 7 5

4 . 7 8

3-92

>5 .00

3 . 4 0

4 . 2 2

- 26* -

1?. FIIM UNSHARPNESS

During some of the image quality investigations the IQI's were also

exposed directly on the cassette of the X-ray film, without any filtration

of steel. Thus the inherent film unsharpness could be determined by read­

ing the diameter of the smallest wire of the IQI, which was visible in the

radiograph.

From fig. **9 the geometric unsharpness can be determined »-»King into

account that:

(y = 2o mm (focus size)

F = 2ooo mm (focus-film-distance)

d = 0.2^ mm (diameter of the thinnest wire)

c = 1.5 mm (thickness of the front side of the cassette)

s = 1.5 mm (largest thickness of the front intensifying screen)

This geometric unsharpness can be neglected because it is only 12.5#

of the diameter of the thinnest wire in the penetrameter (Mo. 12 - o.25 mm).

Therefore the minimum visible wire of the indicator will be the direct

measure of film unsharpness.

Table 12 gives the results of film unsharpness measurements, which

were made with three sets of ISO 101*6 1/7; 6/L2 and I0/I6.

Table 12. Film unsharpness

Film

GAF 100

GAF 200

GAF 400

D 2

D 4

M

Screens

1+1 Pb

Density

2.08

2.25

3.24

2.58

Minimum visible wire

No.

11

11

10

11

diameter - mm

0.32

0.32

0.40

0.32

Table 12 continued

Film

GAF 100

GAF 200

GAF 400

D 2

D 4

H

GAF 100

GAF 200

GAF 400

D 2

D 4

H

GAF 100

GAF 200

GAF 400

D 2

D 4

H

GAF 100

GAF 200

GAF 400

D 2

D 4

M

GAF 100

GAF 200

GAF-400

D 2

D 4

H

GAF 100

GAF 200

GAF 400

D 2

D 4 M

Screens

1+1 Pb

1.5+1.5 Pb

1.5+1.5 Pb

1.5+1-5 Pb

1.5+1.5 PD

1.5+1.5 Cu

Density

I.56

1.44

1.27

2.94

1.22

1.10

1.30

1.40

1.65

2.20

1.80

2.20

2.37

3.39

2.42

1.58

1.42

1.40

4.17

1.58

1.58

1.30

1.40

1.65

2.20

1.80

2.98

2.40

1.86

2.75

1.68

2.46

Minimum visible wire

Ho.

10

9 10

11

10

10

11

10

11

11

11

10

11

11

11

9

10

9 10

11

9 11

10

11

11

11

11

12

11

12

11

11

diameter - mm

0.40

0.50

0.40

0.32

0.40

0.40

0.32

0.40

0.32

0.32

0.32

0.40

0.32

0.32

0.32

0.50

0.40

0.50

0.40

0.32

0.50

0.32

0.40

0.32 0.32 0.32

0.32 0.25 0.32 0.25

0.32 0.32

- 2 6 -

As can be seen all the films showed an. inherent unsharpness better (8)

than 0.32 mm. This value is quoted by Halmshaw for 2 MeV X-rays,

whereas for lo KeV X-rays 0.65 BB can be expected«

14. BCPGSURE CHARTS

From characteristic curves of X-ray films and intensifying screens

(see table 1) and the attenuation curve in steel (see fig. 29) exposure

charts were computed. Figs. 3o and 51 show the exposure charts for the

0.15 + o,25 an Pb-screens, and fig. 52 gives a comparison for Kodak Micro—

tex and Structurix D2 and D** films for density 3* On figs. 53 to 55 ex­

posure charts for 1 + 1 mm Pb-screens are shown whereas fig:* 56 shows a

comparison for Kodak Microtex, Structurix D2 and lA and GAF loo, 2oo and

4oo films.

Similar exposure charts for 1.5 + 1.5 mm Pb-screens are shown on

figs. 57 to 60. Figs. 6l to 63 give the exposure charts for the 1 + 1 am

Cu-screens, and figs. Sk to 6? for the 1*5 + 1*5 mm Cu-screens.

In the way described above (characteristic curves taken without steel

filtration + attenuation curve in steel) exposure charts for 1 + 1 ma Pb;

1.5 + 1*5 nm Pb; 1.5 + 1*5 am Cu-screens were computed whereas exposure

charts for the 0.15 + o.25 mm Pb; 1 + 1 mm Cu, SHP lol; SMP 30I screens

were computed directly from characteristic curves taken directly through

different filtration of steel (see figs. 2o and 22 to 28).

A comparison between the two methods of computing exposure charts are

made for Kodak Microtex film exposed with 1 + 1 mm Pb-screen and shows

good agreement between these two methods. For that purpose figs. 53 and

68 were used (fig. 68 is taken from ( 9 ) ) .

From the exposure charts, one will see that exposure times were very

short. For 25o mm of steel and film density of 3 X-ray films used with

the faster fluorometalxc screens needed an exposure of only 2.5 min.,

whereas for the slower films (Structurix 1)2 or GAF loo) an exposure of

about 15 min. is needed.

- 29 -

15. SUMMARY OF CONCLUSIONS

From the investigations described the following conclusions can be

drawn:

1) It has been proved that radiography of steel up to 25o mm with the

Rise lo MeV linear accelerator is feasible with relatively short ex­

posure times.

2) The investigations have shown that a good radiographic image contract

can be obtained (o.5$K

3) To reach better radiographic image quality (as judged by the use of

image quality indicators) it is essential to have a smaller focus for

the production of X-rays. This is possible, but at the cost of ex­

tending exposure times. An attempt will be made in the future to

foculize the electron beam on the Bremsstrahlung converter to such an

extent, that good IQI sensitivity is obtained.

k) From the point of view of radiographic image contrast Kodak Microtex

film witn 1 + 1 mm Pb screens gives best results in thicker steel

sections (above 15o mm). In the region from 5° to 15o mm Fe fluoro-

metalic screens give even better radiographic contrast and at the same

time reduce exposure time.

5) From the point of view of radiographic image quality (as judged by the

wire IQI), thick lead screens (1 + 1 or 1.5 + 1.5 mm) with Kodak

Microtex film give the best results. Optimum sensitivity is reached

at about 15o mm Fe.

6) For the highest radiographic image contrast and quality, thick lead

screens present most advantages with a fine grain film like Kodak

Microtex. Such screens are comparatively cheap and easy to handle,

which is not true of e.g. tantalum screens, as advertised by several

investigators•

- 3° -

16. DEFERENCES

1. Brynjolfsson, A., Thaarup, G., Determination of Beam Parameters and

Measurements of Dose Distribution in Materials Irradiated by Electrons

in the Range of 6 MeV to 1<» MeV. Rise Report No. 53. 1963.

2. Hansen, Johnny, A lo NeV Bremsstraolung Converter. Rise Report M-1261

ISBN 87 55° oo6U 9, 1971.

3* Sehested, K., in: Hanual on Radiation Dosimetry. Edited by Holm, N.W.

and Berry, R.J., Marcel Dekker, New fork, 1976.

km Iaurence, G.C., Ball, L.W. and Archibald, V.J., National Research

Council of Canada Bulletin, 19^2.

5* Johns, H.E. and Garret, C : Sensitivity and Exposure Graphs for

Radiun Radiography. Non-Destructive Testing. Vinter 19*i9-5o» PP* 16-

6. Domanus, J. and Osuchowski, B.: A Comparative Method of Investigation

for Optimum Conditions in Radiography by Means of a Slotted Hedge (in

Polish). The Problem Sessions Series of the Polish Academy of Sciences.

XXVI. WrocXaw-Varszawa-Krakew, 1965.

7. American Standards Association. ASA. PH2.8-1964. American Standard

Method for the Sensitometry of Industrial X-ray Films for Energies up

to 3 Million Electron Volts.

8. Halmshaw, R«, Industrial Radiology Techniques. Vykeham Publications

(London), Ltd., 1971.

9. Domanus, J«, Analysis of Exposure Factors Influencing the Image

Quality in Linear Accelerator Radiography. Rise-M-1579* 1973*

8 tu

~ K -

A)|SIM}U| »A!W>1«8

Fig. 2. Intensity distribution in the X-«ay beam.

•m

250

.

- ^

300 m

^_____^

900 . —1

- 300 »

—uoo

p—-• 300

1

.

J

S

1

m f 1.25 2.5 5,0 12.«

é%

— X * i

0.120 0.20 Of 1.0 »

Pig. 5- Construction of the slotted steel wedge.

V *

36

Fig. 8. Slatted steel wedge surrounded with masking plates.

Fig. 9.

- 37 -

IF i i t t • K 11 11 m y Kil U P S P ^ • * -

Assembled steel blok with slotted

1 ' 1 ;*"v

\"

wedge.

- 38 -

• — • : - a — —

• i i i

Q oo tø NJ CM ' i i i i

3 co o> *r cg c r r

•

• ^ ^ ^

? OD t ø "X CM C 3 a> u> *» oi C

11

11

i i

i i

• i

i 1

11

11

* w ~ ^ w \ V \ \

\ N » -\ N 1

X N V X N \

\ \ l

; to iø c «

Fig. 10. Characteristic curves (no filtration) for Kodak Microtex

films.

- 59 -

CM O

1 1 1 1

~-~^Z^- -

•

1 • * ^ ™ * " * •**

TI

II

f i

r i

i i

i i

i i

11

TT

TT

TT

"J-

1 —

"

• i i i O co tf) >T CM Q CO ( Ø - f f C M Q a t Ø N T C N Q O D t Ø - i f N C in •<» <n c4 ~

NX \\ -\ x V" \ \ V \ \ V \ \ V vi VI

• I I I CD tf <f N

Fig. 11. Characteristic curves (no filtration) for Structurix

D 2 films.

• in -

a

I 1 1 1

P CD tD •* CM <• D -»

i 1 1 1 ? CD <0 -T CM C

•

i i i i > ao tp ** c* c i c

^ " ' N t *

? 4D (ø <f N C 4 *"

-

11

1 1 1

1—1—

1

J L

1

1 1

1 1

1

" \ \ \ ^ \ \ -

eo $£> - * CM

Fig. 12. Characteristic curves (no filtration) for Structurix

D >t films.

• M •

——^~~

~!&££m

', G

AF

o co to

100

•tf CM <

•

3 < D i D < t n Q g S | p 4 ( N ( * n t

} (0 |0 < N C

-

1 1

J.U

J.

-

1 1 1 1 1 T

T

" 1

N> \ 1-X^ \ \-V* \ r \ \ \V-

\ M I \\\f

i i i i

CO V> • * W

Fig. 13« Characteristic curves (no filtration) for GAF 100 films.

- "* -

O (O (O 4 n P (D i O 4 N O O i O 4 N q O ( O 4 N 2 < D l 0 ui •>» p> w "^

FIR. I1*. Character is t ic curves (no f i l t r a t i o n ) for GAF 200 films.

- * » 3 -

~ ^ - — 2 - — . _

-2ast§i

,

: G

AF

Q ø v tn

O

o

. - . i — j . „

— " * * — • • • . -

• i i i

•

i i

i i

i ii

i

11 i i i i—

i 1

i i

11

-

-

/ 1

/ /

i i i

il

111

( O | D < f ( M Q 0 S ( D 4 N C <D ID • * W

Fig. 15. Characteristic curves (no filtration) for GAF <t00 films.

. M* •

Fig. 16. Characteristic curves (no filtration) without intensifying

screens.

4 5 -

Q 00 <0 •* CM O O tf 3 W Q «D (0 5 Ol g • «0 •* t*

Fig. 17. Characteristic curves (no filtration) with 1+1 mm Pb screens.

-46-

Jg

m _l I L_ -I L.

g eo 10 »i <x P a> e < ) n p « S 4 N S « ( i 4 i i J c e ' i i )

Fig. 18. Characteristic curves (no filtration) with 1.5+1*5 mm Pb screens.

-*7-

Fig. 19. Characteristic curves (no filtration) with 1.5+1.5 mm Cu screens

48-

Fig. 20, Characteristic curves (through 50-150 nun Fe) for Kodak

Microtex films with 0,15+0.25 Pb screens.

•49-

O OD (0 -X O* P CO (0 *tf C M P CB |0 4 IN Q O ( 0 ^ M g * «* irt « * <** f*

Fig, 21. Characteristic curves (through 50-250 mm Fe) for Kodak Microtex

films with 1+1 mm Pb screens.

5o - 51-

g • <D •» « g o> ID <

Fig. 22. Characteristic curves (through 50-150 nm Fe) for Kodak Microtex

films with 1+1 mm Cu screens.

. . , | . , , , | , i i i i i i i i i i

0> ( 0 »* <* Q •> (0 <* N Q O? > U 4 n q « i g 4 « 3 c a ' '

Pig. 23. Characteristic curves (through 50-250 aa Fe) for Kodak Microtex

films with S KP 101 screens.

52- - 53-

Fig. PM. Characteristic curves (through 50-250 nm Fe) for Kodak Hicrotex

films with SMP 501 screens.

s • «. * " s - * * « Fig. 25. Characteristic curves (through 50-150 •* Fe) for Structurix D 2

films with 0.15+0.25 mm P* screens.

- 5 * - • 55 -

o s ID 4 N Q o <o •» ex P o» io >» « 9 <Å «tf •"» » ^

O ^* ex g CD «p < ex. ^

Fig. 26. Characterietic curves (through 50-150 mm Fe) for Structurix D 2

films with 1+1 mm Cu screene*

Fig. 27. Characteristic curves (through 50-150 am Fe) for Structurix

D if films with 0.15+0.25 nm Pt> screens.

10' 57 •

Fig. 28. Characteristic curves (through 50-150 mm Fe) for Structurix

D *f films with 1+1 Cu screens.

10'

10l

10

k

V.

10J

10

10'

10" 50 100 150 200 250mmFe

Fig, 2Q. Attenuation curve in steel.

- 5 8 -

250

g 10 20 30 LO 5 0 60 70 80 9 0 ^ 0 <° 2 0 3 0 4°1506 0 7 0 8 0 9 0 2 0 0 1 0 2 0 3 0 *° 250 mm Fe

Fir- 30- Visibility of slotted wedge on Kodak M film with 1+1 mm Pb screens.

59 •

- 0 , 0 2 0 3 0 40 go 60 70 80 90,0010 2 0 3 0 4° ) 5o60 ™ 80 90 20010 20 30 40 rø mm F*

Fig. 31. Viaibility of slotted wedge on Kodak M filme with

SHP 101 screens.

- 6o -

g 10 20 30 40 50 60 70 80 90JQQ10 20 30 4 0 1 5 Q 6 0 70 80 90 20010 2 0 3 0 *°250

mm Fe

V'w. y?. Visibility of slotted wedge on Kodak H films with

KKP 301 screens.

- 6 1 -

0 10 20 30 40 gø 60 70 80 9 0 1 0 Q 1 0 20 30 40,5(560 70 80 90 200'0 20 3 0 4 0 2 5 0 • mmFe

Fig. 33. Visibility of slotted wedge on Kodak « films with

0.15+0.25 mm Pb screens.

6 2 •

250

0 10 20 30 40 5 0 60 70 80 90,0 ( )10 20 30 4 0 ^ 6 0 70 80 90 2'o010 2 0 3 0 *°250 mm Fe

Fi/'. V K Visibility of slotted wedge on Kodak M films with

1+1 mm Cu screens.

- 6 3 -

10;

10'

r

10'

50

- r -100 150 200 250

D2 0.15+0.25 Pb

5%D

0 5 % | |

J I L. )p ,_ r 0 » 20 30 40 g'o 60 70 80 90 j 0 0 10 20 30 40 ) f;060 70 60 90 200'0 2 0 3 0 *°250 .

* mm Ft

fig. 35- Visibility of slotted wedge on Structurix D 2 filM with

0.15+0.25 na Pb screens.

(A

250

0 10 20 30 40 gø 60 70 80 9 0 1 0 Q 1 0 20 30 4 0 ^ 6 0 70 80 90 20010 2 0 3 0 *° 250 mtnFe

:'\r,. ~tf>. V i s i b i l i t y of s l o t t e d wedge on S t r u c t u r i x D 2 f i l m s with

1+1 mm Cu s c r e e n s .

- 6 5 -

10!

10'

« "3 Q.10-E

10'

101

50 100 150 200 250

DA 0.15+0.25 Pb

J L_ l L. _l [_

5%n

0 . 5 % | |

i i i i_ 0 10 20 30 40 50 60 70 80 9 0 1 0 Q 1 0 20 30 40 1 5 060 70 80 90 20010 2 0 3 0 *°250\

mmFe

Pig. 37. Vis ib i l i ty of slotted wedge on Stmcturix D 4 films with

0.15+0.25 mm Pb screens.

- 6 6 •

50 100 150 200 250

D4 1+1Cu

J L. - I I L_ l_

5%n

0 . 5 % | |

I I I I - I l _ _ l _ 0 10 20 30 40 5 0 60 70 80 9 0 1 0 Q 1 0 20 30 40 1 5 0 60 70 80 90 2001 0 20 3 0 *°250

mmFe

Fig. 38. Visibility of slotted wedge on Structurix D <J films

with 1+1 mm Cu screens.

C7 •

Fig. 39. Scanning densitometer.

~>

"3> c Ol 0)

c *> o

50 mm

lOOmm

I50mm

200mm 250mm

IO N n ^ l f l S t O O N V O H I M l

Fig. kO. Per cent IQI sens i t i v i ty .

•/.

£ *+

^ Ot (o | s 10 u

2

o

CM

O

O

o < o

GA

F 20

0 -

GA

F 1

00

1 1

) <« n N . i i i

*"

- 6 9 -

- *7 0 * « f * c o i n - * « n e M o i i i i •

> ^

— —

.«--

— ^ s - - -*^

I — 1 — 1 — 1 —

1 1 1 1

„25

0

C O

c

in

,nZ5

0

S!

i in

S

t

n'5

0o

in

o

C

m'5

0,

O

o esi

C

n'5

°7

5

•n

S ,N

S

a s

o o

— o ø> <ø .p- *© m

Fig. 4l. IQI sensitivities for 1+1 mm Pb screens.

to tn »c co CM

- Vo -o — o 9 r*

1

o

CM

O

O O

u. < o

GA

F 20

0 -

GA

F 1

0U

i i

'

— i — i i -i—

^

N \

__^~——' '

n •**

__| ' ' '

1 1 1 1

/

y

N } J

'^N, /

S*

I I I !

1 1 1 1 1

— 1 l _ l 1

O

CM C

c O

c

o in

o CM

C c

O

c

in

o CM

C

„15

0,

S

m

S 1

,«1

50

, m

o CM

C

n1

50

,

m

o in

c

n'5

0„

: :

to in sj co CM r* <ø in . * m CM

FIR. h?. IQI s ens i t i v i t i e s for 1+1 mm Pb screens.

/I Q

f£f4 Ok 00 C«- tO U

SP

b

i

<

s

o

CM

o

o . o

< o

GA

F 20

0 -

GA

F 1

00

) «» n N ^ -1 l 1 i

* O* « c (O »o » co CM 3 1 1 1 1

V \ , , ^

" ^

\

\

y

j J ->r

^ " - " /

V

^N y

i i i r

9 o> CB r*> u> ih sr r» CM ^ o oi e > IØ iA 4 co CM «-

o CM

O

CM

O

o

in

o m CM

O

CM O

O

in

o CM

O CM

O in

o

i n l

o

CM

O IM

O in o

o

o in CM

O

CM O

o

o m

o m

s CM

O

"s e

Fig. <*3. IQI sensitivities for 1.5+1.5 nm Pb screens.

- 7 2 •

^ oi co t> tø u i

Q

CM

O

GA

FA

OO

G

AF

20

0 -

GA

F

100

: i

i i

i • * n o j . - • 1 1 1 >

" u - -

-' o> ce c^ o « l 1 1 i

" X

-

} z ^ M

1 • ' •

» -tf O CM o

1 i • •

O

CN

8 CM

O ttl

O

o in

o Ol

O

CM O

O

o i n

o CM

O

CM O m

Q

O

» , O

CM O

CM O m

o

o

o CM

O CM

O

O

u>

o in CM

CM

O

o

co »fl sr n c M t — O c n a > r < » < ø m « ? f * } C M « —

TQI Gensi t ivi t ies for 1.5+1*5 mm P*> screens.

73 -

- 1 .

2

o

CM

O

GA

F A

OO

G

AF

20

0 -

GA

F

100

3 C* (O U

1 1

J < n N . t .

~ 1 — -1 1 1 "

^ ^

______r '

____—-—'

n .

^

- H -

e» <o t*> co u —1- I " ! 1

*x /

K

' s J

y

\ )

y

~ \ \

/

- ^ u

7 * /

• i i i

^ -» en CM ^ 1 1 ! 1

c c

c

c L

< C

<

. < < <

• <

•

<

< L f

C

c u

c V

c

C

1 I I 1 le <n CM r- o a> tn *M . -

- ' - O o P^ O U

2

Q

CM

O

O O •

l i .

<

GA

F 2

00

- G

AF

100

i i 1 -c n rj _ w

. i ,,,..,.1 _,—

" " ' .

•

^

O CD C* <D *

1 1 I i

\ \

^

N

y

\

r S

" " • ^ u

/

s

n ^ co <M o

-

s c*

S "s

S \ S i!

S o

S

•fe CM

s y

O <

»»

s! ~s

CM

g 2

S "8 S *S o H

.

s s 5

S g S

« - lf\

I f l ID ^ O (M ^ p O ) 0 0 f * - ( O l i O ^ « * > * • —

- 7 5 -

:

3

-*?

: r » a>

2

•tf

o

CM

GA

F 40

0 G

AF

200

- G

AF

100

o> co

CO js . tø

1 1 r* tø m

» MT «"» CM ^

• j n IN ^ o

P

^

^

Ok

i ! —i—r-

N

.

S. 3 ^ A-

\ /

^

J /

co 'r* to in

T — 1 — 1 — r ~

I" - 5 S

- i - i !

* S

2

S

a o

ft h* S

S

• E

° F

~s I-s !£!

" = ir>

S "g => i' o

• o

m

o

CM

s CM

O

. o

m

MT rn <N p-

7. 2.5

2.0

1.5

1.0

05

M x-0.15+0.25 Pb — O-1 + l Pb — — • -

5

1.5+

fc, V

0 «

1.5 P

,

S

» 1 !

b -

) i 30 21

/

» 2

;

50

M x-1 +1 Cu — — 0-15+1.5CU — —

5

[

\

\

OK

<

X) 1«

\

50 21

i

'/

M2!

i

30

M x-SMP 101 O-SMP301

<

:

S

w .

s t o

%

,3> o

0 100 150 200 250

02 x-0.15«O25Pb— 0 - 1 + 1Cu —

i

\ —<

** ^~

i

50 100 150

DA x-QJ5*025Pb— O - 1 + I C u — —

\

V V i \ \ \ \

N>

i

50 100 150 mm Fe

Fig,^8 • IQI sensitivities for different film- screen combinations

- 7 8 -

10O 150 mm

Fig.50. Exposure charts for Kodak MwithO,15 + 0.25 mm Pb screens

- 79 -

4

3

2

1.5

io9< a 7 6 5

4

3

1.5

io93

7 6 5

4

3

2

1.5

in2

D2

z.

~ -D4 --

0.15* 0.25 Pb -

-

-

10 min

5-min-

2 min

1.5 min

lmin 50s

25s 20s

15s

10s

5s

0=2

0=3

0=2

50 100 150 mm

Fig.51. Exposure charts for Structurix D2 ana Dk with 0.15 + 0.25 «™ Pb screens

- 8 o -

10 min

5-min-D=3

D=3

150 mm

Fig, 52. Comparison of exposure charts from f igs . 50 and 51

- 8 1 -

9 s 7 6 5

i

3

2

1.5

10' 9 e 7 6 5

t

3

2

1.5

103

I 7 6 5

4

3

2

1.5

'o,2

s 7 6

10'

-

S 3 a

-/ /

M U1 Pb

/ / / / ' /'

/ / SS s'

's^S SS s'

^** ^** s\^-. /

—

-D=3

D=2

" " -

" -

1. s

l li)

" -50 100 150 200 250 mm Fe

Fig.53« Exposure charts for Kodak M with 1 + 1 mm Pb screens

- 82 -

5 10' 250mm Fe

Tig.5k. Exposure charts for Stucturix D2 and D^ with 1 + 1 mm Pb screens

- 8 3 -

IOV 9 " 8 -7 -6 -

5 10'

7 -6 -

¥

y

GAF H1Pb

: ^ p y

/

/

100

200

/

y

> r ^

400

50 100 150 200 250mmFe

fig-55- Exposure charts for SAP films with 1 + 1 mm Pb screens

- 8 * t -

1CS

c

5-10'

-

-

---

-" ---

_ « 3 Q

"b

-

-

1*1 Fb

Jsyté

$2?

•p/\ ' ^ ^

•>-»

^ s * * * ^ 0 " 3 t* i

c=a 3=3 D=3

-

.

1-xp

osur

e

UJ

50 100 150 200 250mm Fe

Fig.56. Comparison of exposure charts from f igs . 53 to 55

- 8 5 -

10* I

1.5

10'

1.5

103

15

10/

• in'

-

ses

3 a

-F

M 15+1.5Pb

^Ss^" S^S*'^

SS Ss

S'S SS

SS / , '

/ ' '

-

1 1

1 1

1

• . -

• •

-

D=3

D=2

--

_

i s

Ex p

c

-

50 100 150 200 250 mm Fe

Fig.57. Exposure char ts for Kodak K with 1.5 + 1-5 """ P* screens

- 86 -

1 7 i

5 L

3

2

10' 9 e 7 i 5

l

3

2

1.5

,«1 Ur

9 8

6 5

l

3

2

1.5

102

9 8 7 6

10'

I

----

_

S -—

3 • i

^

•

.

1.5+15Pb

/ / / / '

./' y * ^r

/ / ' ,/'

02

y/l,'

, / ' . * j ^ ^

/ / S *

/

yT s

yS S

' ' ^S

04 s'^y' ur . ^

'1/ é*

^sS0^ .+ ^>r ^<0>*^

y s'

^s^>

y'

D=3

D=2

D=3

D=2

-

--

1-i 1-u

" -

20 min

I5min

10 min

5 min

2min

1.5 min

Imin 50s

2Ss 20s

50 100 150 200

S- 10s

5s

2.5s 25

1.5s

250mmFe

Fig,58. Exposure charts for Structurix D2 and n't with 1.5 + 1,5 mm Pb screens

- 8 7 -

9 8 7 6 5 t

3

2

1.5

10' 9 8 7 6 5

2

1.5

103

I 7 6 5 (

.3

2

1.5

if 8 7 6

in'

æ 3 a - £

GAF 15*15 Pb

.-•

-

j^p1^ ^*^^*

^ 7 ^ ^<K ^ ^O^ 100 . ^ ^ » ^ ^ "

• O > v^> > ; / • •

fe^r -y ' /

--_.

--

*

y^Z^" s^y' y'.

°=3 0=3 D=2 D=2

D=3 D=2

-

-

i me

1 1

1 ..1

. ir

et

1 a. UJ

_

-50 100 150 200 250 mm Fe

Fig,59. Exposure charts for QAF film's with 1.5 + 1-5 ""» Pb

9 8 7 6 5

3

2

1.5

o' 9 B 7 6

5

4

3

2

1.5

O3

9 S 7 6 5

4

3

2

1.5

O2 U9 8 7 6

n'

----

-

--

--" -

s - in

a "E

•S *\i

s • ~ s t ~ ~

z -U

1.5+1.5 Fb

y

sT y ^

yy^ s *y y% ^ Ssr

yC-y yyr y ^

^ y^

^y

yw y/y^

' /it y y ^

y ^ 'yy y

y^. ~y^r

^y^^^y^

j i ^ ^ s

° k < ^ ^y^^

t®

^ ^

y^s***^ <r

^y^^ J ^ ^ \ J > ^ ^ ^ ' ^

^s^s^^ ^

0=3 D=J Efc3

n j

3=3

-

-

Of

. i -os

ure

-•

-

20 min

1 5 m i n

10 min

5 min

2 m i n

1.5min

I m i n

50 s

25 s

20 s

15s

•S- 10s

5s

50 100 150 200

2.5s 2s

1.5s

250 mm Fe

Fig.60. Comparison of exposure charts from figs.57 to 59

4

3

2

1.5

e 7 6 5

4

3

2

1.5

H3

7 6 5

4

3

2

1.5

in2

-. -

•

-

---

M 1 + ICu

-

-

-

_

10 min

5 min

2 min

1.5 min

Imin 50s

25s 20s

15s

10s

5s

50 100 150 mm

F i g . 6 1 . Exposure c h a r t s f o r Kodak M w i a 1 + 1 mm Cu screens

- 9o -

4

2

IS

8 7 6

5

i.

3

1.5

°93

8 7 b

5

3

2

1.5

n2

-

_

D2

DA

-

1+1Cu

-

-

-

"10 min

5 min

2 min

Imin .50 s

25s 20s

15s

10s

5s

D=2

50 100 150 m m

Fig.62. Exposure charts for Structurix D2 and Dk with 1 + 1 mm Cu screens

- n -

0=3

150 mm

Fig.63. Comparison of exposure charts fro» f igs . 61 and 62

-92 -

I U ' 9 8 7 6

i

3

2

1.5

10' 9 8 7 6

L

3

2

1.5

I03

9 8 7 6 5

t

. 3

2

t.5

KJ* 9 8 7 6

in'

I

-

.

S . J/l

3 0 • E

k

"

--•

M 1.5+1.5CU

/ /

/ / ' / '

s ' s

/ / '

. / '

y//S''

/V s'

^*s^^ S^ y^' S'

D=3

D=2

-

-

-" ~

-

i-os

ure

. •

50 100 150 200 250 m m Fe

Fig.64. Exposure charts for Kodak K with 1.5 + 1.5 mm Cu screens

9 3 -

7 •

5 •

5 •

2

15

1.5*1.5Cu

/ /

D2

D4

. - 0 = 2

r io.3-

/ /

y /

2 •

1.5 •

K 6 -

5i0' 50 100 150 200

Fig. 65. Exposure charts for Structurix D2 and Dlf with 1.5 + 1.5 mm Cu screens

' 20mln

• 15 min

' 10 min

• 0=2

5min"

• 2min

• 1.5 min

• Imin 50s

25 s 20s

15s

10s

i 5s

•2.5s

2s

• 1.5s

250 mm Fe

-9 1*-

5 10' ' 50 250 mm Fe

Fig.66. Exposure charts for OAF films with 1.5 + 1.5 mm Cu screens

- 9 5 -

M

10' I 7 6 5 & 3

2

IS

10' 9 8 7 6 5 I

3

2

1.5

t 7 8 5 1 3

2

1.5

8 7 6

5-0

a

1.5+1.5Cu

50 100

Fig.67* Comparison

—

JKx

"JSP

150

of exposure charts

200

froo f igs .

1=3

£

i X III

20 min

15min

10 min

5 min

2min

1.5 min

Imin 50s

25s 20s 15s

10s

5s

2.5s 2s

1.5s

250mm Fe

$k to 66

- s -

250 mm Fe

Fig.63. Exposure charts for Kodak M with 1 + 1 mm Pb and SMP 101 and SMP 301 screens