Heat Flow Below 100°k and its Technical Applications. Proceedings of the International Institute of Refrigeration Commission 1, Grenoble, 1965

109 Pages·1966·4.033 MB·English

by  The International Institute of Refrigeration (Auth.)

INTERNATIONAL INSTITUTE OF REFRIGERATION
INSTITUT INTERNATIONAL DU FROID
HEAT FLOW BELOW 100°K
AND ITS TECHNICAL
APPLICATIONS
PROCEEDINGS OF THE
INTERNATIONAL INSTITUTE OF REFRIGERATION
COMMISSION 1
GRENOBLE 1965
SYMPOSIUM PUBLICATIONS DIVISION
PERGAMON PRESS
OXFORD - LONDON - NEW YORK - PARIS - BRAUNSCHWEIG
EDINBURGH - TORONTO
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Copyright © 1966
The International Institute of Refrigeration
and Pergamon Press Ltd.
Edited by the International Institute of Refrigeration
and distributed by Pergamon Press Ltd.
Library of Congress Catalog Card No. 59-15722
PRINTED IN BELGIUM BY CEUTERICK IN LOUVAIN
3002/63
PREFACE
IN NOVEMBER 1969 the International Commission on Radiological Protection adopted a
Report by Committee 3 entitled Protection against Ionizing Radiation from External Sources,
which was issued in the following year as ICRP Publication 15. The task of compiling material
for that publication was undertaken by a Task Group whose membership is given below. The
Task Group also assembled data that were intended to form appendices to the report, but the
death of its secretary, Β. E. Jones, led to delays, which were minimized by the decision to issue
the appendices as a separate supplement. Accordingly, the Commission, at its meeting in April
1971, appointed a new Task Group, the membership of which is also given below, to complete
the preparation of the data for the supplement.
Task Group (1967-71) Task Group (1971-72)
P. GRANDE {Chairman) M. C. O'RIORDAN {Chairman)
K. BECKER {Vice-Chairman) M. J. DUGGAN
Β. E. JONES {Secretary) T. O. MARSHALL
J. P. KELLEY Ε. E. SMITH
K. KOREN
C. B. MEINHOLD
P. PELLERIN
R. H. THOMAS
Membership of Committee 3 during the preparation of ICRP Publication 15 and the Supple-
ment:
B. LINDELL {Chairman) H. O. WYCKOFF (to 1969)
Ε. E. SMITH {Vice-chairman) J. P. KELLEY (from 1969)
L.-E. LARSSON Ε. E. KOVALEV (from 1969)
F. P. COWAN R. OLIVER (from 1969)
S. TAKAHASHI P. PELLERIN (from 1969)
J. DUTREIX (to 1969) K. A. ROWLEY (from 1969)
E. D. TROUT (to 1969)
This report also includes amendments to ICRP Publication 15 and extracts from a statement
issued by the Commission in April 1971.
V
AMENDMENTS TO ICRP PUBLICATION 15
Paragraph 17
Delete the third, fourth, and fifth sentences and replace with the following: "When the
incident radiation is neutrons only and the tissue kerma free in air (in rads) is known, this
kerma may be assumed to be numerically equal to the absorbed dose in rads at any point in
the body, provided the dose from the capture gamma rays can be ignored. In such circumstances,
if the energy of the incident neutrons is not known, a QF of 10 should be assumed. The capture
gamma rays become important when a significant part of the neutron spectrum lies below
0.1 MeV, because in these circumstances the capture gamma rays could give rise to a maximum
absorbed dose in the body which is as much as 100 times that due to charged particles produced
by other neutron reactions. An alternative approach is to use a suitable rem-meter to give an
adequate determination of the dose equivalent."
Paragraph 19
After "Appendices 6 and 7" insert the words "of the supplement".
Paragraph 84
For "20:108" write "108".
vi
COMMISSION STATEMENT ON EXTERNAL
RADIATION SOURCES
AFTER the meeting of the International Commission on Radiological Protection in April 1971,
a statement was issued, which included two items on external radiation sources. These
statements are reproduced below.
Exposure from intra-oral x-ray tubes
The Commission was informed about a new radiation protection problem posed by the use
of intra-oral x-ray tubes in dental radiography. With the present trend to use tubes of decreasing
diameter, the radiation doses at the surface of the tube may amount to between 50 and 100
rads, or even more, per exposure. Such uses should be clearly deprecated. It is of interest to
note that intra-oral x-ray tubes, if used with the appropriate filtration and extra-sensitive
films, may not give higher doses than 5-10 rads to limited parts of the tongue. With these
precautions the intra-oral tubes may even have certain advantages from the point of view of
radiation protection: they cause lower integral doses than regular dental tubes, and the
exposure of the staff is much reduced. Extra "shielding in the applicator can easily limit the
radiation field to that which is needed for the examination, thus further reducing the integral
dose.
Population dose from consumer products
The Commission noted the increasing use of a number of consumer products containing
small amounts of radioactive material, and the contribution to the population dose that these,
taken together, could make, even though the dose from individual sources is at present
extremely small. In considering the relevance of this to the dose limit for the population, the
Commission emphasized the importance of national authorities assessing the contribution
being made by these products, so that an effective means of control may be instituted. In this
regard, the Commission wishes to draw attention to a publication of the Nuclear Energy
Agency (Basic approach for safety analysis and control of products containing radio-nuclides
and available to the general public, 1970), as an example of a method by which the total
individual and population doses from all consumer products may be subject to administrative
control.
vii
LIST OF FIGURES
FIG. 1. Collision stopping power of protons and electrons in water as a function of energy 42
FIG. 2. Quality factor as a function of collision stopping power in water 43
FIG. 3. Quality factors of charged particles as a function of energy. 44
FIG. 4. Dose equivalent as a function of depth in a 30 cm thick slab of tissue irradiated normally, on one
face, by a broad beam of monoenergetic neutrons 45
FIG. 5. Dose equivalent as a function of depth in a 30 cm thick slab of tissue irradiated normally, on one
face, by a broad beam of monoenergetic protons 46
FIG. 6. * Calculated percentage depth-dose distributions in water for broad beams of normally incident
monoenergetic electrons of high to very high energy 47
FIG. 7. Percentage depth-dose distributions in tissue-like material for beta particles from large plane
sources virtually in contact with the material. (The maximum energies of the beta particles, in
MeV, are shown in parentheses.) 48
FIG. 8. Percentage depth-dose distributions along the minor axis of an elliptical water phantom for
broad beams of low and high energy photons, from an infinitely distant source, incident in the
same direction 49
FIG. 9. Backscatter factors at the surface and 5 cm from the surface of an elliptical water phantom for
broad beams of low and high energy photons incident along the minor axis 50
FIG. 10. Average dose absorbed in the testes per unit exposure measured by a personal dosemeter on the
front of the trunk (curves A and B) and per unit exposure measured in free air at the position of
the centre of the body (curve C). Curve A: irradiation from the back only. Curve Β: irradiation
from the front only. Curve C: rotation during exposure simulating irradiation from all sides 51
FIG. 11. Average dose absorbed in the ovaries per unit exposure measured by a personal dosemeter on
the front of the trunk (curves A and B) and per unit exposure measured in free air at the position
of the centre of the body (curve C). Curve A: irradiation from the back only. Curve Β: irradiation
from the front only. Curve C: rotation during exposure simulating irradiation from all sides 52
FIG. 12. Average dose absorbed in bone marrow per unit exposure measured by a personal dosemeter on
the front of the trunk (curves A and B) and per unit exposure measured in free air at the position
of the centre of the body (curve C). Curve A: irradiation from the back only. Curve B: irradi-
ation from the front only. Curve C: rotation during exposure simulating irradiation from all
sides. 53
FIG. 13. Conversion factors for electrons. Unidirectional broad beam, normal incidence. The curve
indicates the values recommended by the Commission 54
FIG. 14. Conversion factors for neutrons. Unidirectional broad beam, normal incidence. The curves
indicate the values recommended by the Commission 55
FIG. 15. Effective quality factors for neutrons, that is, maximum dose equivalent divided by the absorbed
dose at the depth where the maximum dose equivalent occurs. The curve indicates the values
recommended by the Commission 56
FIG. 16. Conversion factors for protons. Unidirectional broad beam, normally incident on a 30 cm thick
phantom. The curve indicates the values recommended by the Commission 57
FIG. 17. Conversion factors for photons. Unidirectional broad beam, normal incidence. The curves
indicate the values recommended by the Commission 58
FIG. 18. Relationship between photon fluence rate and exposure rate 59
FIG. 19. Broad-beam dose equivalent transmission of 14-15 MeV neutrons through slabs of concrete,
density 2.4 g/cm3, and water 60
FIG. 20. Broad-beam dose equivalent transmission of 14-15 MeV neutrons through slabs of steel (density
7.8 g/cm3) and polyethylene (0.94 g/cm3) and a combination of steel and polyethylene 61
FIG. 21. Broad-beam dose equivalent transmission of 241Am-Be neutrons through water and through
polyethelene, density 0.94 g/cm3 62
FIG. 22. Broad-beam dose equivalent transmission of 252Cf neutrons through slabs of lead (density
11.35 g/cm3) and polyethylene (0.96 g/cm3) 63
FIG. 23. Broad-beam absorbed dose transmission of 252Cf gamma rays through slabs of lead (density
11.35 g/cm3), steel (7.8 g/cm3), and concrete (2.35 g/cm3)
FIG. 24. Neutron dose equivalent rates at the surfaces of spheres of polyethylene (density 0.96 g/cm3) 64
paraffin (0.92 g/cm3), water, and concretes (2.35 g/cm3), each with 1 μ% 252Cf at its centre 65
FIG. 25. Neutron absorbed dose transmission through slab shields of unidirectional broad beams of
0.5 MeV neutrons incident at various angles to the slabs 66
ix
χ LIST OF FIGURES
FIG. 26. Neutron absorbed dose transmission through slab shields of unidirectional broad beams of 67
1 MeV neutrons incident at various angles to the slabs
FIG. 27. Neutron absorbed dose transmission through slab shields of unidirectional broad beams of
2 MeV neutrons incident at various angles to the slabs 68
FIG. 28. Neutron absorbed dose transmission through slab shields of unidirectional broad beams of
5 MeV neutrons incident at various angles to the slabs 69
FIG. 29. Range of electrons and protons in air 70
FIG. 30. Range of electrons, protons, and alpha particles in water 71
FIG. 31. Range of electrons, protons, and alpha particles in lead 72
FIG. 32. Bremsstrahlung from 106Rh beta particles stopped in the metal matrix; also from 90Y, 90Sr,
147Pm, and 171Tm beta particles stopped in the oxide matrices 73
FIG. 33. Absorbed dose transmission of diverging broad beams of bremsstrahlung from 90Sr-90Y beta
particles stopped in the oxide matrix through slabs of steel (density 7.8 g/cm3), lead (11.35 g/
cm3), and uranium (18.9 g/cm3). Beam axes normal to shields. See note in text regarding
uranium 74
FIG. 34. Output of constant potential x-ray generator at 10 cm target distance for various beam nitrations
and a tungsten reflection target. The 1 mm beryllium is the tube window. For output at 1 m, see
Glassere/fl/. (1959) 75
FIG. 35. Output of constant potential x-ray generator at 1 m target distance for various beam nitrations
• and a tungsten reflection target. The 1 mm beryllium is the tube window 76
FIG. 36. Output of constant potential x-ray generators at 1 m target distance for various beam nitrations.
The upper curve. is for a 2.8 mm tungsten transmission target followed by 2.8 mm copper,
18.7 mm water, and 2.1 mm brass. The other curves are for tungsten reflection targets with
0.5 mm and 3 mm copper total filtration 77
FIG. 37. X-ray output of linear accelerators, per unit average beam current, 1 m from a high atomic
number transmission target of optimum thickness. The ordinate is the absorbed dose rate
measured in air. This chart may also be used for betatrons, although the target configuration is
different 78
FIG. 38. Broad-beam transmission of χ rays through mild steel, density 7.8 g/cm3. Constant potential
generator; tungsten reflection target; 1 mm beryllium total beam filtration. Ordinate intercepts
are: 8.38 at 50 kV; 6.58 at 40; 4.49 at 30. 79
FIG. 39. Broad-beam transmission of χ rays through Perspex, density 1.2 g/cm3. Constant potential
generator, tungsten reflection target; 1 mm beryllium total beam filtration. For ordinate
intercepts, see Fig. 38. 80
FIG. 40. Broad-beam transmission of χ rays through concrete, density 2.35 g/cm3. 50 to 300 kV: half-
wave generator; tungsten reflection target; total beam filtration 1 mm aluminium at 50 kV, 1.5
at 70, 2 at 100, and 3 at 125 to 300. 400 kV: constant potential generator; gold reflection target;
3 mm copper total beam filtration. Ordinate intercepts are 2.7 at 400 kV, 2.4 at 300, 1.6 at 250,
1.02 at 200, 0.6 at 150, 0.45 at 125, 0.32 at 100,0.24 at 70, 0.19 at 50. 81
FIG. 41. Broad-beam transmission of χ rays through lead, density 11.35 g/cm3. Constant potential
generator; tungsten reflection target; 2 mm aluminium total beam filtration. Ordinate intercepts
are 3.3 at 200 kV, 2.1 at 150, 1.1 at 100, 0.7 at 75, 0.3 at 50. 82
FIG. 42. Broad-beam transmission of χ rays through lead, density 11.35 g/cm3. 250 kV: constant poten-
tial generator; tungsten reflection target; 0.5 mm copper total beam filtration. 300 and 400 kV:
constant potential generator; gold reflection target; 3 mm copper total beam filtration. Ordinate
intercepts are 2.7 at 400 kV, 1.3 at 300, 1.9 at 250
83
FIG. 43. Broad-beam transmission of χ rays through concrete, density 2.35 g/cm3. Constant potential
generators. 0.5 and 1.0 MV: 2.8 mm tungsten transmission target followed by 2.8 mm copper,
18.7 mm water, and 2.1 mm brass beam filtration. 2 MV: high atomic number transmission
target; 6.8 mm lead equivalent total beam filtration. 3 MV: gold transmission target; 11 mm lead
equivalent total beam filtration. Ordinate intercepts are 850 at 3 MV, 300 at 2, 20 at 1,1 at 0.5
84
FIG. 44. Broad-beam transmission of χ rays through lead, density 11.35 g/cm3. Constant potential
generators. 0.5 and 1.0 MV: 2.8 mm tungsten transmission target followed by 2.8 mm copper,
18.7 mm water, and 2.1 mm brass beam filtration. 2 MV: high atomic number transmission
target; 6.8 mm lead equivalent total beam filtration. Ordinate intercepts are 300 at 2 MV, 20 at
1,1 at 0.5
85
FIG. 45. Broad-beam transmission of χ rays through concrete, density 2.35 g/cm3. 4 MV: linear acceler-
ator; 1 mm gold target followed by 20 mm aluminium beam flattener. 6-38 MV: Betatron;
target and filtration not stated. The 38 MV curve may be used up to 200 MV (Miller and
Kennedy, 1956) 86
FIG. 46. Broad-beam transmission of χ rays through lead, density 11.35 g/cm3. Betatron; platinum wire
target 2 mm χ 8 mm; no beam filtration. For higher potentials, see Miller and Kennedy (1956) 87
FIG. 47. Broad-beam transmission of gamma rays from various radionuclides through concrete, density
2.35 g/cm3 88
LIST OF FIGURES xi
FIG. 48. Broad-beam transmission of gamma rays from various radionuclides through concrete, density
2.35 g/cm3 89
FIG. 49. Broad-beam transmission of gamma rays from various radionuclides through steel, density
90
7.8 g/cm3
FIG. 50. Broad-beam transmission of gamma rays from various radionuclides through lead, density
91
11.35 g/cm3
FIG. 51. Broad-beam transmission of gamma rays from various radionuclides through lead, density 92
11.35 g/cm3
FIG. 52. Broad-beam transmission of gamma rays from various radionuclides through uranium, density 93
18.9 g/cm3. See note in the text of Appendix 11 regarding uranium
FIG. 53. Variation with potential of the absorbed dose rate measured in air due to χ rays scattered at 90°
from various materials. The beam is obliquely incident on the thick scatterer. Per cent scatter is 94
related to primary beam measurements in free air at the point of incidence
FIG. 54. Scattering patterns of diverging x-ray and gamma-ray beams normally incident on a concrete
shield. Per cent scatter is related to primary beam measurements in free air at the point of 95
incidence
FIG. 55. Broad-beam transmission of 137Cs gamma rays scattered at various angles from an oblique 96
concrete wall through concrete, density 2.35 g/cm3
FIG. 56. Broad-beam transmission of l37Cs gamma rays scattered at various angles from an oblique 97
concrete wall through lead, density 11.35 g/cm3
FIG. 57. Broad-beam transmission of 60Co gamma rays scattered at various angles from a patient- 98
simulating phantom through concrete, density 2.35 g/cm3
FIG. 58. Broad-beam transmission of 60Co gamma rays scattered at various angles from a patient- 99
simulating phantom through lead, density 11.35 g/cm3
FIG. 59. Broad-beam transmission of 6 MV χ rays scattered at various angles from a patient-simulating 100
phantom through concrete, density 2.35 g/cm3
LIST OF TABLES
TABLE 1. Summary of depth-dose calculations in tissue for neutrons, protons, electrons, and photons 7
TABLE 2. Dose equivalent rate as a function of depth in water for normally incident unidirectional
broad beams of electrons and photons 7
TABLE 3. Conversion factors for electrons 10
TABLE 4. Conversion factors and effective quality factors for neutrons 12
TABLE 5. Conversion factors and effective quality factors for protons 14
TABLE 6. Conversion factors and mass energy absorption coefficients in water 0*βο/ρ) for photons 16
TABLE 7. Energy of neutrons produced by different nuclear reactions involving light nuclei 18
TABLE 8. Characteristics of some radioactive neutron sources 18
TABLE 9. Neutron fluence rates and dose rates 1 m from 1 g 252Cf 19
TABLE 10. Photon fluence rates and dose rates 1 m from 1 g 252Cf 19
TABLE 11. Composition of materials used in calculations for Figs. 25-28. 20
TABLE 12. Characteristics of the beta sources considered in Appendix 11 22
TABLE 13. Photon energy groups and emission rates selected for the shielding calculations for brems-
strahlung from 90Sr-90Y beta particles stopped in the SrO matrix 23
TABLE 14. Outputs of gamma-ray sources 24
TABLE 15. References and irradiation geometries for x-ray and gamma-ray transmission data 26
TABLE 16. Approximate half-value-thicknesses and tenth-value-thicknesses for heavily attenuated broad
beams of χ rays 27
TABLE 17. Approximate half-value-thicknesses and tenth-value-thicknesses for heavily attenuated broad
beams of gamma rays 27
TABLE 18. Lead equivalence of various materials for low energy χ rays 28
TABLE 19. Per cent of absorbed dose rate due to incident radiation scattered to 1 m by a tissue-like
phantom for 400 cm2 irradiated area 29
TABLE 20. Primary x-ray beam shielding requirements for 0.1 rem per week 33
TABLE 21. Scatter and leakage x-ray shielding requirements for 0.1 rem per week 34
xii
INTRODUCTION
THIS publication is the Supplement to ICRP with the general shielding bibliography on
Publication 15 (1969) referred to in the page 41.
Preface to that report. It consists of twelve In 1971 the International Commission on
appendices, which are numbered in accord- Radiation Units and Measurements published
ance with references in the text of Publication a report entitled "Radiation Quantities and
15. Units" (ICRU Report 19, 1971), which
The appendices contain information for superseded a report with the same title pub-
implementing the recommendations of ICRP lished in 1968. ICRU Report 19 proposed
Publication 15 and therefore relate to the new symbols for some terms in radiation
sources of external radiation encountered in protection, and these new symbols have been
medical, dental, and veterinary radiology, introduced here. ICRP Publication 15, how-
and in industry and research. The reader will ever, uses the old symbols, and the following
appreciate the difficulty of selecting and com- changes should be noted: dose equivalent,
pressing material for presentation in this Η for DE; quality factor, Q for QF.
form and the need to consult the original .The International Commission on Radi-
references as occasion demands. ation Units and Measurements recommends
A substantial portion of the Supplement is the use of the International System of Units
allocated to data on shielding, but some (SI) for fundamental quantities, but continues
shielding problems, such as those associated to recognize some existing special units.
with nuclear reactors and ultra high energy Accordingly, the International Commission
accelerators, are outside its scope. There is, on Radiological Protection will continue to
however, a copious shielding literature, and use the special units and certain other con-
an excellent citation service is provided by the ventional multiples and submultiples of units,
Radiation Shielding Information Center at until agreement is reached for their abandon-
Oak Ridge National Laboratory. The creation ment. The following tabulation of quantities
of the European Shielding Information in SI and special units is extracted from
Service at Ispra has recently been announced. ICRU Report 19, to which the reader is
The addresses of both organizations are given referred for a fuller discussion of the subject.
Name Symbol SI unit Special unit
Absorbed dose D J kg"1 rad
Absorbed dose rate ύ Jkg^s"1 rads"1
Exposure X Ckg-1 R (roentgen)
Exposure rate X A kg"1 Rs"1
Linear energy transfer U Jm"1 keV/xm-1
Activity A s-1 Ci (curie)
1