X-ray lines relative intensity depending on detector efficiency, foils and cases thickness for primary and scattered spectra
Primary and Compton scattered radiation spectra from radioactive source ²⁴¹Am were measured in various geometry and for various targets. Spectral lines intensity of characteristic X-ray radiation (CXR), Compton and Rayleigh scattering are defined. The back scattering peak for a line 59.54 keV was ex...
Збережено в:
| Дата: | 2011 |
|---|---|
| Автори: | , , , |
| Формат: | Стаття |
| Мова: | English |
| Опубліковано: |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2011
|
| Назва видання: | Вопросы атомной науки и техники |
| Теми: | |
| Онлайн доступ: | http://dspace.nbuv.gov.ua/handle/123456789/111134 |
| Теги: |
Додати тег
Немає тегів, Будьте першим, хто поставить тег для цього запису!
|
| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | X-ray lines relative intensity depending on detector efficiency, foils and cases thickness for primary and scattered spectra / G.L.Bochek, O.S.Deiev, N.I.Maslov, V.K.Voloshyn // Вопросы атомной науки и техники. — 2011. — № 3. — С. 42-49. — Бібліогр.: 12 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| id |
irk-123456789-111134 |
|---|---|
| record_format |
dspace |
| spelling |
irk-123456789-1111342017-01-09T03:03:27Z X-ray lines relative intensity depending on detector efficiency, foils and cases thickness for primary and scattered spectra Bochek, G.L. Deiev, O.S. Maslov, N.I. Voloshyn, V.K. Ядернo-физические методы и обработка данных Primary and Compton scattered radiation spectra from radioactive source ²⁴¹Am were measured in various geometry and for various targets. Spectral lines intensity of characteristic X-ray radiation (CXR), Compton and Rayleigh scattering are defined. The back scattering peak for a line 59.54 keV was explored. X-ray quanta were registered by the packaged Si detector 300mm and input Al foil 10mm thicknesses. Radiation interaction with targets and detector atoms was simulated in software code GEANT 4 (LE). Simulated spectra, quanta registration efficiency and secondary calculated radiation spectra at 90º...160º are compared with experimentally measured energy distributions. Виміряні прямі і комптонівськи розсіяні спектри від радіоактивного джерела ²⁴¹Am в різній геометрії для різних мішеней. Визначені інтенсивності рентгенівських ліній характеристичного рентгенівського випромінювання (ХРІ), комптонівського і релеєвського розсіяння в розсіяних спектрах. Вивчався пік зворотнього розсіювання для лінії 59.54 кeВ. Рентгенівські кванти реєструвалися корпусованим Si - детектором товщиною 300 мкм і вхідною фольгою Al товщиною 10 мкм. У програмному коді GEANT 4 (LE) моделювалася взаємодія випромінювання з атомами мішені і детектора. Розраховані спектри випромінювання ²⁴¹Am, ефективність реєстрації квантів, спектри вторинного випромінювання, розсіяного під кутами 90º...160º, порівнюються з первинними енергетичними розподілами. Измерены прямые и комптоновски рассеянные спектры излучения от радиоактивного источника ²⁴¹Am в различной геометрии для различных мишеней. Определены интенсивности рентгеновских линий характеристического рентгеновского излучения (ХРИ), комптоновского и рэлеевского рассеяния в рассеянных спектрах. Изучался пик обратного рассеяния для линии 59.54 кэВ. Рентгеновские кванты регистрировались корпусированным Si - детектором толщиной 300 мкм и входной Al фольгой толщиной 10 мкм. В программном коде GEANT 4 (LE) моделировалось взаимодействие излучения с атомами мишени и детектора. Расчетные спектры излучения ²⁴¹Am, эффективность регистрации квантов и спектры вторичного излучения, рассеянного под углами 90º...160º, сравниваются с экспериментально измеренными энергетическими распределениями. 2011 Article X-ray lines relative intensity depending on detector efficiency, foils and cases thickness for primary and scattered spectra / G.L.Bochek, O.S.Deiev, N.I.Maslov, V.K.Voloshyn // Вопросы атомной науки и техники. — 2011. — № 3. — С. 42-49. — Бібліогр.: 12 назв. — англ. 1562-6016 PACS: 07.85.Fv, 61.80.Cb http://dspace.nbuv.gov.ua/handle/123456789/111134 en Вопросы атомной науки и техники Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| language |
English |
| topic |
Ядернo-физические методы и обработка данных Ядернo-физические методы и обработка данных |
| spellingShingle |
Ядернo-физические методы и обработка данных Ядернo-физические методы и обработка данных Bochek, G.L. Deiev, O.S. Maslov, N.I. Voloshyn, V.K. X-ray lines relative intensity depending on detector efficiency, foils and cases thickness for primary and scattered spectra Вопросы атомной науки и техники |
| description |
Primary and Compton scattered radiation spectra from radioactive source ²⁴¹Am were measured in various geometry and for various targets. Spectral lines intensity of characteristic X-ray radiation (CXR), Compton and Rayleigh scattering are defined. The back scattering peak for a line 59.54 keV was explored. X-ray quanta were registered by the packaged Si detector 300mm and input Al foil 10mm thicknesses. Radiation interaction with targets and detector atoms was simulated in software code GEANT 4 (LE). Simulated spectra, quanta registration efficiency and secondary calculated radiation spectra at 90º...160º are compared with experimentally measured energy distributions. |
| format |
Article |
| author |
Bochek, G.L. Deiev, O.S. Maslov, N.I. Voloshyn, V.K. |
| author_facet |
Bochek, G.L. Deiev, O.S. Maslov, N.I. Voloshyn, V.K. |
| author_sort |
Bochek, G.L. |
| title |
X-ray lines relative intensity depending on detector efficiency, foils and cases thickness for primary and scattered spectra |
| title_short |
X-ray lines relative intensity depending on detector efficiency, foils and cases thickness for primary and scattered spectra |
| title_full |
X-ray lines relative intensity depending on detector efficiency, foils and cases thickness for primary and scattered spectra |
| title_fullStr |
X-ray lines relative intensity depending on detector efficiency, foils and cases thickness for primary and scattered spectra |
| title_full_unstemmed |
X-ray lines relative intensity depending on detector efficiency, foils and cases thickness for primary and scattered spectra |
| title_sort |
x-ray lines relative intensity depending on detector efficiency, foils and cases thickness for primary and scattered spectra |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| publishDate |
2011 |
| topic_facet |
Ядернo-физические методы и обработка данных |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/111134 |
| citation_txt |
X-ray lines relative intensity depending on detector efficiency, foils and cases thickness for primary and scattered spectra / G.L.Bochek, O.S.Deiev, N.I.Maslov, V.K.Voloshyn // Вопросы атомной науки и техники. — 2011. — № 3. — С. 42-49. — Бібліогр.: 12 назв. — англ. |
| series |
Вопросы атомной науки и техники |
| work_keys_str_mv |
AT bochekgl xraylinesrelativeintensitydependingondetectorefficiencyfoilsandcasesthicknessforprimaryandscatteredspectra AT deievos xraylinesrelativeintensitydependingondetectorefficiencyfoilsandcasesthicknessforprimaryandscatteredspectra AT maslovni xraylinesrelativeintensitydependingondetectorefficiencyfoilsandcasesthicknessforprimaryandscatteredspectra AT voloshynvk xraylinesrelativeintensitydependingondetectorefficiencyfoilsandcasesthicknessforprimaryandscatteredspectra |
| first_indexed |
2025-07-08T01:40:12Z |
| last_indexed |
2025-07-08T01:40:12Z |
| _version_ |
1837040992378683392 |
| fulltext |
X-RAY LINES RELATIVE INTENSITY DEPENDING ON
DETECTOR EFFICIENCY, FOILS AND CASES THICKNESS
FOR PRIMARY AND SCATTERED SPECTRA
G.L.Bochek, O.S.Deiev∗, N.I.Maslov, V.K.Voloshyn
National Science Center ”Kharkov Institute of Physics and Technology”, 61108, Kharkov, Ukraine
(Received April 1, 2011)
Primary and Compton scattered radiation spectra from radioactive source 241Am were measured in various geometry
and for various targets. Spectral lines intensity of characteristic X-ray radiation (CXR), Compton and Rayleigh
scattering are defined. The back scattering peak for a line 59.54 keV was explored. X-ray quanta were registered
by the packaged Si detector 300 µm and input Al foil 10 µm thicknesses. Radiation interaction with targets and
detector atoms was simulated in software code GEANT 4 (LE). Simulated spectra, quanta registration efficiency and
secondary calculated radiation spectra at 90◦...160◦ are compared with experimentally measured energy distributions.
PACS: 07.85.Fv, 61.80.Cb
1. INTRODUCTION
The experimental and calculated radiation spectra
are changing essentially, if the radiation source or
the detector is placed in the protective container.
Lines intensity of low-energy radiation is reduced
and, at the same time, lines CXR from a container
material and a line of ”back scattering” peak are
registered. Numerical processing of primary and
Compton scattered radiation spectra from X-ray and
gamma radiation source (241Am, 57Co, 137Cs, 60Co
etc.) demands the complete experiment description:
its geometry, the foil thickness, energy and inten-
sity of primary X-ray lines, efficiency of the quanta
registration and the energy resolution of the detec-
tor. Program code GEANT 4 allows considering all
these details and becomes an important methodi-
cal base of the experiment description. Compton
and Rayleigh spectra were measured and computed
for 241Am source in earlier work [1, 2]. We used of
X-rays from a radioactive source 241Am for study
of the primary and Compton scattered spectra, in-
tensity of radiation lines registered by a thin silicon
detector. In this case quanta registration efficiency
has an important role. Radioactive sources are con-
venient for verification of spectrometric channels by
preparation for experimental study of properties of
the X-rays eradiated by electrons in crystals (called
”channeling radiation” [3, 4, 5, 6]). For measuring
of such radiation it is necessary know all features of
quanta registration in this energy interval. For mea-
suring of intensive X-rays spectra it is necessary to
use secondary targets - scatterers with the Compton
scattering spectra registration under a certain angle.
The experimental method on base of Compton scat-
tering for gamma radiation spectra measuring from
electrons with energy of 1200 MeV in single crystals
has been earlier described and used in [7, 8, 9]. Appli-
cation of the Compton scattering method for X-ray
radiation it was studied in works [9, 10, 11]. The pur-
pose of the present work is: - investigation of X-rays
lines intensity depending on experimental conditions
(registration efficiency, the foil and container thick-
ness, the scattering angle); - experimental measuring
and GEANT 4 modeling of primary X-rays scatter-
ing process on atoms of the target - scatterer in low
energy radiation interval (< 60 keV ); - restoration
of experimental and computing spectra to compare
with experimentally measured primary X-ray spec-
tra and make conclusions about Compton scattering
procedure possibilities and its optimization.
2. THE EXPERIMENTAL TECHNIQUE
AND MODEL
Radiation spectra from two radioactive source 241Am
are measured, one of which is placed in the protec-
tive container. The X-ray quanta was registered
by the packaged Si detector 300 µm thickness with
size 1.8 × 1.8mm2 and input Al foil 10 µm thick-
ness. The intensity of lines, ”back scattering” peak
and 241Am spectra after passage through targets
with various thickness was measured. Secondary ra-
diation scattering spectra at angles 90◦...130◦ was
measured on targets with different Z. The distance
between the source and target was 10 cm. The ra-
diation source was collimated, the angular resolu-
tion of detecting system was specify by the sizes
of a silicon detector. Lines CXR, Compton and
Rayleigh spectra were observed. Intensity of lines
∗Corresponding author E-mail address: deev@kipt.kharkov.ua
42 PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY, 2011, N3.
Series: Nuclear Physics Investigations (55), p.42-49.
was calculated by summation of the areas under cor-
responding peaks by fitting in program OriginPro 8.
Then intensity of lines was normalized on Si de-
tector registration efficiency for quanta with cor-
responding energy. In program code GEANT 4
(processes/electromagnetic/LowEnergy), installed
on platform ScientificLinux 4, was computed pri-
mary X-rays interaction with a target material in
energy range 1...60 keV . The scattering quanta and
secondary radiation yield depending on Z targets
were calculated. By means of a Monte-Carlo method
primary radiation spectra 241Am source were mod-
eled. The X-ray quanta flux was going to a target-
scatterer. Then primary quanta was scattered and
registered by the Si detector at angles 90◦...160◦.
These scattering spectra were restored on the proce-
dure [7] and compared with primary radiation spec-
tra. The restoration procedure is based on Compton
and Klein-Nishina formulae [10]. On evidence of coin-
cidence or discrepancy primary and restored spectra
we conclude about possibility of using Compton-
restore procedure. The spectra distortions from ad-
ditional radiation (like CXR)in target are considered.
These distortions make difficulties or do impossible
of primary spectrum restoration. In GEANT 4 (LE)
X-ray quanta registration efficiency for thin Si de-
tector 300 µm thickness are calculated. The strong
dependence of registration efficiency from quanta en-
ergy was shown and take into account in the lines
intensity restoration. Computed results are com-
pared with measured and tabular data.
3. INFLUENCE OF THE DETECTOR
EFFICIENCY, FOILS AND CONTAINER
THICKNESS ON THE RADIATION
REGISTRATION
In Fig.1 calculated efficiency of X-ray quanta
registration by the Si detector 300 µm and
input Al foil 10 µm thicknesses are shown.
Fig.1. Calculated efficiency of the X-ray quanta
registration by Si detector 300 µm and input Al foil
10 µm thicknesses
Total efficiency ηt is response at presence of any de-
tector reactions on transiting X-ray quantum, pho-
topeak efficiency ηph is X-ray quantum registration
with energy total absorption. Calculated results have
shown that efficiency of detecting system reaches a
maximum 0.87 for energies of quanta nearly 9 keV ,
then efficiency decrease with quantum energy increas-
ing. Efficiency is almost equal 1 up to E = 8 keV
in the absence of a input Al plate. In the energy
interval up to 25 keV the total efficiency ηt practi-
cally coincides with value of efficiency ηph. Difference
between efficiencies ηt and ηph increase with energy
increasing: for E = 50 keV values ηt and ηph are
0.0268 and 0.0154, for E = 60 keV are 0.0198 and
0.0087, for E = 80 keV are 0.014 and 0.0033, respec-
tively. The calculated efficiency take into account on
restoration experimentally measured lines intensity
to real value. In Fig.2 two experimental radiation
spectra 241Am are shown. Spectra measured at an-
gle 0◦ for two types of source: one for the thin
source, second for the intensive source in the steel
cylinder container with thin exit window (150 µm).
Fig.2. The experimental radiation spectra 241Am,
measured at angle 0◦ for two types of source: 1 -
thin source; 2 - intensive source in the steel cylinder
container
The standard radiation spectrum 241Am con-
sist from several lines with known energy
13.95, 17.74, 20.8, 26.348 and 59.54 keV and the rel-
ative intensity 0.33, 0.487, 0.123, 0.062 and 1, re-
spectively. Such description of lines conventionally
as the resolution of silicon detectors with room tem-
perature does not allow to resolve thin structure
of some lines. The most intensive line is the line
with energy 59.54 keV whereas in experiment with
the thin source (spectrum 1) it is weak because
of the low registration efficiency. After normaliza-
tion on computed efficiency obtained out following
values of the relative intensity lines: 0.31, 0.494,
0.123, 0.066 and 1. Such result is satisfactory, the
error is related to the resolution of the detector
FWHM = 1.1 keV that has not allowed to lines
structure resolving and we can‘t take into account
efficiency more correct. The experimental radiation
spectrum (Fig.2, curve 2) for intensive source in the
steel cylinder container have some differences against
radiation spectrum of thin source 241Am. Low en-
43
ergy radiation lines are adsorb by container wall,
there are only lines with energy 13.95, 20.8, 26.348
and 59.54 keV , the lines intensity relation becomes
another. Besides, in the left part of the spectrum
Compton scattering ”tail” with top energy 11.25 keV
was appeared. The peak of K-line CXR from Fe
with energy nearly 6.4 keV were also observed. The
back scattering peak for the line 59.54 keV with
a maximum nearly 49 keV are observed. This
peak was noticeably widely for straggling of scat-
tering angles. Fig.3 are presented calculated in
GEANT 4 X-ray quanta spectra in 300 µmSi de-
tector without the Fe container (top) and with pres-
ence Fe foils, thickness 100 µm and 150 µm (down).
Fig.3. Calculated in GEANT 4 X-ray quanta
spectra 241Am (FWHM = 0.94 keV ) in 300 µmSi
detector without Fe container (top) and with pres-
ence Fe foils 100 µm (red curve) and 150 µm (blue
curve) thickness(down)
The computed results for a 150 µmFe foil are
very similar to experimental measured spec-
trum for packaged source (Fig.2, curve 2).
The low-energy lines 13.95, 20.8, 26.348 keV have
the same intensity. Thus, we have possibility
to determine a source container foil thickness.
Fig.4. Radiation spectra 241Am measured in
identical geometry. Red curve - packaged 241Am
source, blue curve - the same spectrum after passage
through the C layer with the thickness 9.5 mm
In Fig.4 are shown two radiation spectra 241Am
measured in identical geometry, but in one container
(blue curve) between source and the detector the
C layer with the thickness 9.5 mm was disposed.
We can see that in radiation spectrum with C layer
all radiation lines was decreased, Compton ”tail”
decreased too and CXR Fe peak disappear. Ex-
perimental peaks are fitting and defined the areas
under them. Lines were attenuated unequally with
increase of quanta energy. For the line with energy
E = 17.8 keV attenuation of radiation is 2.59, for
E = 20.8 keV -1.89, for E = 26.34 keV - 1.6, for
E = 33.2 keV - 1.46 and for the line E = 59.54 keV -
1.3; for energy interval 49...53 keV - 1.34. Almost
identical attenuation of intensity radiation 1.3...1.35
for three spectral regions generated by the line
E = 59.54 keV (Compton ”tail” 8...10 keV , back
scattering peak 49...50 keV and a line 59.54 keV )
are observed. Influence of the surrounding materi-
als on radiation spectra was experimentally studied.
The thin source 241Am was closely put to an input
diaphragm of the Si detector. Behinde the source
placed different plates (0.5...10 mm) from materials
with various Z and then were measured radiation
spectra. The back scattering peak was increase non-
uniformly to increasing Z. In case plate absence the
intensity relation line with energy 59.54 keV to back
scattering peak have maximum 13.19, i.e. the back
scattering peak has the minimum quantity. The in-
tensity relation with increasing Z of plates were: C -
10.5 (Z = 6), Al - 9.93 (Z = 13), Fe - 10.73 (Z = 26),
Zn - 11.05 (Z = 30), Zr - 10.85 (Z = 40), Cd - 10.02
(Z = 48), Sn - 11.82 (Z = 50), Pb - 12.9 (Z = 83).
It is difficult to reveal precise regularity because it
is necessary to use thin foils of equal thickness. Fol-
lowing dependence are determined - the more CXR
quantity from a line 59.54 keV is excited in a plate,
the less back scattering peak increase. The CXR lines
exciting in plates are good visible and these deformed
a radiation spectra against ”a pure” source spectra.
Fig.5. ”Deformed” radiation spectrum from thin
241Am for Cd plate with 0.5 mm thickness disposed
behind the source
In Fig.5 such deformed spectrum for a Cd plate
with 0.5 mm thickness are shown. Between radia-
44
tion peaks 241Am E = 20.8 and 26.348 keV was
arise additional peak CXR from Cd with energy
Kα = 23.17 keV .
In Fig.6 radiation spectra for thin (1) and in-
tensive source in the steel cylinder container (2
and 3) source 241Am are shown. The spectrum
2 corresponds to a direct standing package source
(thin foil forward), and the spectrum 3 is mea-
sured at source backward direction (thick wall of
the container forward).The spectra are normal-
ized on peak E = 59.54 keV value, the logarith-
mic scale is chosen. It is clearly visible that back
scattering peak for package source essentially in-
crease. Besides, we can see that is immediate
to the left side of peak 59.54 keV arise additional
quanta which formed peak left side increase. In
this region placed low angle Compton scattering
quanta. Their quantity in spectrum at passage of
thicker wall of the source container are increase.
Fig.6. Radiation spectra at angle 0◦ for thin (1) and
intensive package source 241Am in the steel cylinder
container (2 and 3). The spectrum 2 corresponds to
direct standing package source (thin foil forward),
and the spectrum 3 is measured at source backward
direction (thick wall of the container forward)
Fig.7. The experimental spectra measured at angle
120◦ for thick samples (3 mm) Fe, Ag and Pb
4. SCATTERED X-RAYS REGISTRATION
BY THE THIN SILICON DETECTOR
The spectra measurement of Compton scattered
quanta on angle 90◦...130◦ was made at room tem-
perature using X-ray quanta from collimated package
source 241Am. The Compton peak for the above ex-
perimental angle is at 49...53 keV . Experimentally
measured spectra consist of CXR lines, Compton
and Rayleigh peaks. In Fig.7 the typical experimen-
tal spectra measured at angle 120◦ for thick samples
(3mm) Fe, Ag and Pb are given. CXR lines are
clearly visible, in the region of energy 49...53 keV
there is a Compton peak, the Rayleigh peak is near
59.54 keV . We can to estimate their relative inten-
sity.
Fig.8. The relation of registration efficiencies ηph
for Ag Kα = 22.16 keV and Kβ = 24.94 keV in
300 µmSi detector for Al, Cu, Mo andAu foils
Easy to estimate a relation of lines in CXR L-triplet
for Pb target. For Pb three lines L series α, β, γ with
energies 10.5, 12.6 and 15 keV are observed. The ex-
perimental relation of intensity lines without correc-
tion on quanta registration efficiency is 7.86, 9.78 and
1, and after the correction on efficiency: 4.76, 7.28
and 1, respectively. Calculation in GEANT 4 gives
3.4, 7.40 and 1. For Ag foil in experimental radiation
spectrum is observed Rayleigh, Compton peaks and
two CXR lines Kα = 22.16 keV and Kβ = 24.94 keV
with the computed relation intensity Kα/Kβ = 4.06
(GEANT 4). For experimental intensity definition it
is necessary to consider efficiency of detecting system
for these lines. In our container efficiency is 0.187 and
0.133 for quanta energy 22.16 and 24.94 keV . The
relation of efficiencies is 1.4. Experimentally mea-
sured (sourse 241Am, scattering angle 120◦) relation
of intensity of lines give Kα/Kβ = 5.62, and after the
efficiency correction it decreases to 4.0 that is close
to calculated 4.06. In Fig.8 relations of registration
efficiencies ηph for these two CXR lines in Si detector
for Al, Cu, Mo, Au foils with various thickness are
presented. For Cu,Mo and Au foils relations of effi-
ciencies smaller 1 are observed already at small foil
thickness. It means stronger absorption of Kα line.
45
Fig.9. Calculated spectrum CXR, Compton and
Rayleigh scattering, registered at angle 120◦ on
Ag foil 0.1 mm thickness. Primary quanta energy
E = 59.54 keV
If a efficiency registration relation is the order 0.25
intensities of CXR Kα and Kβ lines registered in
experiment will be equal. Such effect observed in
[1]. These strong changes lines intensity should be
considered at interpretation of experiment data. In-
tensity relations for CXR lines (Kα/Kβ) and rela-
tions of intensity Compton and Rayleigh scattering
(K = C/R) are presented in Table 1,2. For correc-
tion of the experimental intensity to real the calcu-
lated registration efficiency for quanta was used (see
Fig.1). In Fig.9, 10 the computed scattering spectra
for primary quanta with energy E = 59.54 keV at
registration angle 120◦ for Ag, Fe, Cu target with
the thickness of 0.1 mm are shown. One can see that
for all targets the width of Compton peak always is
more than width of Rayleigh peak. It is related with
Doppler broadening of lines arising at Compton scat-
tering. The relation intensity Compton and Rayleigh
peak K = C/R differs for different Z targets (Ta-
ble 2).
Table 1. Calculation and experimental results of
intensity relation CXR lines (Kα/Kβ)
Z Kα/Kβ Kα/Kβ Data GEANT
exp. exp./Eff [12] 4
Ag 5.62 4.0 4.26 4.06
Sn 6.11 4.31 4.09 4.14
Nb 5.83 4.46 4.57 3.98
In 6.43 4.51 4.15 4.26
Mo 6.25 4.79 4.53 4.26
Zr 5.95 4.53 4.71 4.35
Cd 5.86 4.19 4.15 4.07
Cu 6.87 6.97 7.49 6.62
Dy 6.67 4.24 - 3.6
Table 2. Relations of intensity Compton and
Rayleigh scattering (K=C/R)and CXR. The
scattering angle 120◦
El. Z C R C
R
CXR C
R
CXR
C
exp
C 6 1269 0.83 1523 0. - 0.
Al 13 1566 41 38.19 1 25.6 0.
Ti 22 2459 168 14.64 236 - 0.096
Fe 26 3657 303 12.07 1058 5.8 0.29
Ni 28 4001 384 10.42 1862 6.91 0.46
Cu 29 3846 370 10.39 2531 4.3 0.66
Zr 40 2111 440 4.8 22941 - 10.87
Mo 42 2423 636 3.81 32029 - 13.22
Ag 47 1905 689 2.76 58434 2.08 30.67
Sn 50 1634 606 2.69 69912 - 42.78
W 74 3015 2192 1.38 897 - 0.3
Pt 78 2689 2225 1.21 1483 - 0.55
Pb 82 1939 1836 1.06 2544 1.67 1.31
Bi 83 1728 1697 1.02 2818 - 1.63
U 92 1483 2036 0.73 5678 - 3.83
Fig.10. Calculated spectrum CXR, Compton and
Rayleigh scattering, registered at angle 120◦ on
Fe, Cu foil 0.1 mm thickness. Primary quanta
energy E = 59.54 keV
For scattering quanta with energy 59.54 keV photo
absorption in Ag foil becomes the dominating mech-
anism of interaction and CXR intensive lines are
generated (see Fig.9, top). For Fe, Cu it has
less expressed character (see Fig.10) because K-
edge energy value are less (for Fe = 7.1 keV ,
Cu = 8.98 keV ). The spectrum becomes simpler
for C target, there is only an expressed Compton
scattering peak, the Rayleigh scattering peak and
CXR lines practically misses. The Compton and
Rayleigh scattering contribution in the resultant
spectrum were investigated by calculation proce-
dure in which the quanta flux from modeling spec-
trum 241Am on different target are directed. The
reflected radiation spectra separately computed for
only Compton or Rayleigh scattering. It is possible
in GEANT 4. In Fig.11 one of calculated results for
46
Si scatterer with thickness 2 mm are shown. These
two spectra are computed for detector efficiency 1.
Fig.11. Compton and Rayleigh scattering spectra.
Detector efficiency is 1
Compton spectra are shifted in field of low ener-
gies, the Rayleigh spectra contribution increases with
decrease of quanta energy. All Compton lines are
widened. In Fig.12 the radiation spectrum 241Am,
placed in the steel container and scattering radiation
spectrum on Pb target with thickness 3 mm are pre-
sented. The experimental spectrum (Fig.12, curve 2)
for 241Am intensive source in the steel cylinder con-
tainer have only lines with energy 13.95, 20.8, 26.348
and 59.54 keV . In the left part of a spectrum there
is Compton scattering ”tail” and peak of K-line
CXR from Fe with energy nearly 6.4 keV . For Pb
target three lines L of a series α, β, γ with ener-
gies 10.5, 12.6 and 15 keV are observed. Comp-
ton and Rayleigh scattering is small. The lines
with energy 17.8, 20.8, 26.34 keV are not observed.
Fig.12. The experimental radiation spectra from
241Am at 0◦ - curve 2, and scattering radiation
spectrum on Pb target 3 mm thickness at angle 130◦
- curve 1
In Fig.13 the experimental radiation spectrum
from 241Am for Al target 5 mm thickness,
measured in the same geometry are shown.
Fig.13. The experimental radiation spectrum from
241Am for Al target 5 mm thickness, scattering
angle 130◦
The Compton scattering peak have FWHM =
2.75 keV and Rayleigh scattering peak have
FWHM = 1.24 keV . Calculation in GEANT 4
gives FWHM = 2.5 and 1.2 keV , respectively.
The detector resolution for line E = 59.54 keV
is FWHM = 1.15 keV , for energy 26, 348 keV we
take FWHM = 1.09 keV . Asymmetry of Compton
peak were observed. Radiation lines 17.8, 20.8 and
26.34 keV make visible. In Fig.14 the experimental
scattering quanta spectrum from 241Am for C target
with the thickness 10 mm and calculated (only for the
line 59.54 keV ) scattering spectrum are presented.
Fig.14. Experimental (blue curve)and calculated
(red curve, for line E = 59.54 keV ) scattering
spectra for C target 10 mm thickness, scattering
angle 130◦
The compute scattering spectrum does not give
Compton spectrum asymmetry. Asymmetry is re-
lated to features of 241Am source (presence of
”back scattering” peak). The back scattering peak
forms an ”additional” radiation line with energy
48...53 keV . Energy quanta decreases to 40...44 keV
after scattering at angle 130◦. In this region
the Compton scattering spectra are deformed. In
Fig.15 shown primary radiation spectrum from
47
241Am and the spectra restored after scattering
on a C target with thickness 10 mm at angles 90◦
and 130◦. Spectra normalization is chosen free.
Fig.15. Spectra of 241Am: 1-restored from exper-
imental spectrum scattered from C target 10 mm
thickness under the angle of 90◦; and 2-under the
angle of 130◦; 3-primary spectrum
The strong broadening of primary lines are observed.
The initial width of line FWHM = 1.15 keV for
energy 59.54 keV was increasing after Compton scat-
tering to FWHM = 2, 55 keV , on restore procedure
there was a broadening to FWHM = 4.3 keV . Thus,
narrow primary radiation lines are recovered with the
broadening (influence of Doppler effect). For low Z
targets the Doppler line broadening is less than for
heavy materials. The additional line broadening is
related also with straggling of registration angles.
5. CONCLUSIONS
The primary radiation spectra 241Am source in var-
ious geometry are experimentally measured, CXR
lines, back scattering peak and spectra deforming
near left edge line E = 59.54 keV are studied. Scat-
tering radiation spectra for various targets (CXR,
Compton and Rayleigh scattering) are measured. X-
ray quanta were registered by the packaged Si de-
tector 300µm, input Al foil 10 µm thicknesses. In
software code GEANT 4 (LE) was simulated of pho-
tons interaction with targets and detectors atoms,
radiation spectra 241Am are obtained, quanta regis-
tration efficiency are calculated, scattering radiation
spectra scattering at angle 90◦...160◦ are computed.
Restored scattering spectra were compared with pri-
mary energy distributions. Results of modeling in
program code GEANT 4 (LE) have shown a correct-
ness of its use for radiation spectra calculations. Our
calculation and experiment result are shown the real
practical possibility of spectra restoration at low en-
ergies using Compton scattering procedure. Advan-
tages of use light targets-scatterer are also shown,
the difficulties related with photo absorption process
in a heavy targets are revealed. The strong broad-
ening of primary 241Am lines is observed. The ini-
tial width of line FWHM = 1.15 keV for energy
59.54 keV was incresing after Compton scattering to
FWHM = 2, 55 keV , on restore procedure there was
a broadening to FWHM = 4.3 keV . Thus, narrow
primary radiation lines are recovered with a broad-
ening (influence of Doppler effect).The asymmetry of
Compton scattering spectra are found. Asymmetry
is related to features of 241Am source (presence of
peak of ”back scattering”). The back scattering peak
was formed an ”additional” radiation line with en-
ergy 48...53 keV . The important role of quanta reg-
istration efficiency for restore primary radiation lines
intensity by use a thin silicon detector are shown.
Experimental and calculated CXR intensity relations
Kα/Kβ-lines, intensity Compton and Rayleigh scat-
tering are determined.
References
1. R.Cesareo, A.L.Hanson, G.E.Gigante, et al. In-
teraction of keV photons with matter and new
application//Physics Reports (Review Section of
Physics Letters). North-Holland, 1992, v.213, N3,
p.117-178.
2. S.Wachtel, J.Felsteiner, S.Kahane, et al. Gamma
Ray profile of policrystalline lithium //Phys.
Rev. B. 1975, v.12, p.1285-1292.
3. R.K. Klein, J.O.Kephart, R.H.Pantell, et al.
Electron Channeling Radiation from Diamond
//Phys. Rev. B. 1985, v.31, p.68-92.
4. M.Gouanere, D.Sillou, M.Spighel, et al. Planar
Channeling Radiation from 54...110 MeV Elec-
trons in Diamond and Silicon//Phys. Rev. B.
1988, v.38, p.4352-4371.
5. B.Azaderan, W.Wagner, J.Pawelke. Dependence
of the Linewidth of planar Electron Channeling
Radiation on the Thickness of the Diamond Crys-
tal //Phys. Rev. B. 2006, v.74, p.045209.
6. J.O.Kephart, R.H.Kephart, B.L.Berman et al.
Measurement of occupation lengths of chan-
nelled 17-MeV electron and 54-MeV electron and
positron in silicon by means of channelling radia-
tion //Phys. Rev. B. 1989, v.40, N7, p.4249-4263.
7. D.I.Adeishvili, A.P.Antipenko, S.V.Blazhevich,
et al. Apparatus for measurement of spectral
and angular distributions of gamma quanta at
exit from LUE-2000 linear accelerator //Inst. and
Exp. Techn. 1991, v.34, N2, part.1, p.294.
8. G.L.Bochek, V.I.Kulibaba, N.I.Maslov, et al.
Gamma radiation characteristics of 1.2 GeV elec-
trons in thick silicon single crystals //Nucl. Instr.
and Meth. in Phys. Res. B. 2001, v.173, p.121-
125.
9. G.L.Bochek, V.D.Ovchinnik, V.I.Kulibaba, et
al. Intensive X-ray source optimisation, Interna-
tional Conference on Charged and Neutral Par-
48
ticlea Channeling Phenomena / Edited by Sul-
tan B.Dabagov, Proc.of SPIE (Bellingham, WA).
2005, v.5974, p.5974F-1.
10. A.M.Azartsov, G.L.Bochek, G.P.Vasilev, etc.
About possibility of examination of spectral char-
acteristics of an intensive X-rays of electrons of
medial energies in crystals //Journal of Kharkiv
National University. 2009, v.3/43, N868, p.86-95
(In Russian).
11. W, Wagner, B. Azaderan, M. Sobiella, et
al//Nucl. Instr. Meth. B. 2008, v.266, p.327-334.
12. Tables of physical quantities. Under the editor-
ship of I.K.Kikoin, M: ”Atomizdat”. 1976, p.805
(in Russian).
ОТНОСИТЕЛЬНЫЕ ИНТЕНСИВНОСТИ ЛИНИЙ РЕНТГЕНОВСКОГО
ИЗЛУЧЕНИЯ В ЗАВИСИМОСТИ ОТ ЭФФЕКТИВНОСТИ ДЕТЕКТОРА, ТОЛЩИН
ФОЛЬГ И КОРПУСОВ ДЛЯ ПЕРВИЧНЫХ И РАССЕЯННЫХ СПЕКТРОВ
Г.Л. Бочек, А.С. Деев, Н.И. Маслов, В.К. Волошин
Измерены прямые и комптоновски рассеянные спектры излучения от радиоактивного источника 241Am
в различной геометрии для различных мишеней. Определены интенсивности рентгеновских линий ха-
рактеристического рентгеновского излучения (ХРИ), комптоновского и рэлеевского рассеяния в рас-
сеянных спектрах. Изучался пик обратного рассеяния для линии 59.54 кэВ. Рентгеновские кванты ре-
гистрировались корпусированным Si - детектором толщиной 300 мкм и входной Al фольгой толщиной
10 мкм. В программном коде GEANT 4 (LE) моделировалось взаимодействие излучения с атомами
мишени и детектора. Расчетные спектры излучения 241Am, эффективность регистрации квантов и
спектры вторичного излучения, рассеянного под углами 90◦...160◦, сравниваются с экспериментально
измеренными энергетическими распределениями.
ВIДНОСНI IНТЕНСИВНОСТI ЛIНIЙ РЕНТГЕНIВСЬКОГО ВИПРОМIНЮВАННЯ В
ЗАЛЕЖНОСТI ВIД ЕФЕКТИВНОСТI ДЕТЕКТОРА, ТОВЩИН ФОЛЬГ I
КОРПУСIВ ДЛЯ ПЕРВИННИХ ТА РОЗСIЯНИХ СПЕКТРIВ
Г.Л. Бочек, О.С. Деєв, М.I. Маслов, В.К. Волошин
Вимiрянi прямi i комптонiвськи розсiянi спектри вiд радiоактивного джерела 241Am в рiзнiй геометрiї
для рiзних мiшеней. Визначенi iнтенсивностi рентгенiвських лiнiй характеристичного рентгенiвсько-
го випромiнювання (ХРI), комптонiвського i релеєвського розсiяння в розсiяних спектрах. Вивчався
пiк зворотнього розсiювання для лiнiї 59.54 кeВ. Рентгенiвськi кванти реєструвалися корпусованим
Si - детектором товщиною 300 мкм i вхiдною фольгою Al товщиною 10 мкм. У програмному кодi
GEANT 4 (LE) моделювалася взаємодiя випромiнювання з атомами мiшенi i детектора. Розрахованi
спектри випромiнювання 241Am, ефективнiсть реєстрацiї квантiв, спектри вторинного випромiнюван-
ня, розсiяного пiд кутами 90◦...160◦, порiвнюються з первинними енергетичними розподiлами.
49
|