radiation and safety p. berkvens radiation physics interaction of electrons with matter
DESCRIPTION
Radiation and Safety P. Berkvens radiation physics interaction of electrons with matter interaction of photons with matter interaction of neutrons with matter interaction of protons with matter radiation protection definitions rules radiation fields around accelerators - PowerPoint PPT PresentationTRANSCRIPT
JUAS 2010 – P. Berkvens, Radiation & Safety
1/95
Radiation and SafetyP. Berkvens
1. radiation physics• interaction of electrons with matter• interaction of photons with matter• interaction of neutrons with matter• interaction of protons with matter
2. radiation protection• definitions• rules
3. radiation fields around accelerators• electron accelerators• proton accelerators• synchrotron radiation facilities
4. induced activity
5. radiation monitors
JUAS 2010 – P. Berkvens, Radiation & Safety
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ionisation potential (eV)
carbon 11.260
oxygen 13.618
potassium 4.341
iron 7.870
lead 7.416
of the order of 10 eV required to ionise an atom
electromagnetic radiation:
directly ionising: charged particles (electrons, protons, …) indirectly ionising: photons, neutrons
nm100hc
E
(hard ultraviolet)
Ionising radiation
JUAS 2010 – P. Berkvens, Radiation & Safety
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Radiation and SafetyP. Berkvens
1. radiation physics• interaction of electrons with matter• interaction of photons with matter• interaction of neutrons with matter• interaction of protons with matter
2. radiation protection• definitions• rules
3. radiation fields around accelerators• electron accelerators• proton accelerators• synchrotron radiation facilities
4. induced activity
5. radiation monitors
JUAS 2010 – P. Berkvens, Radiation & Safety
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The physical processes
1. Ionisation lossesinelastic collisions with orbital electrons
2. Bremsstrahlung lossesinelastic collisions with atomic nuclei
3. Rutherford scattering elastic collisions with atomic nuclei
Positronsat nearly rest energy: annihilationemission of two 511 keV photons
Interaction of electrons with matter
JUAS 2010 – P. Berkvens, Radiation & Safety
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Electrons – stopping power
)(MeV.cmpower stoppinglinear :dl
dE
)g.(MeV.cmpower stopping mass :dl
dE1
dl
dE1
dl
dE1S
dl
dE1S
1
12
radcoll
1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03
energy (MeV)
sto
pp
ing
po
we
r (M
eV
.cm
2.g
-1)
collision
radiative
total
Graphite – Z = 6Graphite – Z = 6Graphite – Z = 6Graphite – Z = 6
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03
energy (MeV)
sto
pp
ing
po
we
r (M
eV
.cm
2.g
-1)
collision
radiative
total
Lead – Z = 82Lead – Z = 82Lead – Z = 82Lead – Z = 82
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03
energy (MeV)
sto
pp
ing
po
we
r (M
eV
.cm
2.g
-1)
collision
radiative
total
Copper – Z = 29Copper – Z = 29Copper – Z = 29Copper – Z = 29
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0
E totCSDA
0
dES
1r
Continuous Slowing Down Approximation range
Radiation yield
Fraction of the initial kinetic energy that is converted to bremsstrahlung energy as the electron slows down to rest.
1.E-04
1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03
energy (MeV)
CS
DA
ra
ng
e (
cm
-2.g
)
graphite
copper
lead
1.E-04
1.E-03
1.E-02
1.E-01
1.E+00
1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03
energy (MeV)
rad
iati
on
yie
ld
graphite
copper
lead
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Differential bremsstrahlung cross section
k: photon energyT: electron kinetic energy0
5
10
15
20
25
0 0.2 0.4 0.6 0.8 1
k/T
mb
arn
10 MeV
100 MeV
1 GeV
10 GeV
0
2
4
6
8
10
12
0 0.2 0.4 0.6 0.8 1
k/T
mb
arn
10 MeV
100 MeV
1 GeV
10 GeV
dk
dk
Z
2
1
k/T
k/T
mbarn
lead – Z = 82
carbon – Z = 6
mbarn
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Multiple scattering
dx
d1S
X
X
p
E
2
sc
0
2
s2
mean scattering angle
mass scattering power Ssc
Es = 21.2 MeVX0: radiation length: v/cp: momentum
1.E-05
1.E-04
1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E+00 1.E+01 1.E+02 1.E+03
energy (MeV)
ma
ss
sc
att
eri
ng
po
we
r (r
ad
ian
2.c
m2.g
-1)
graphite
copper
lead
JUAS 2010 – P. Berkvens, Radiation & Safety
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The physical processes
1. Photo-electric effectremoval of an orbital electron of the inner shells (K,L,M)
2. Compton scatteringinelastic scattering on loosely bound electrons
3. Pair production production of e-/e+ pairessentially with nuclei
4. Rayleigh scatteringelastic scatteringnot important for radiation physics
Interaction of photons with matter
JUAS 2010 – P. Berkvens, Radiation & Safety
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1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05
energy (MeV)
cro
ss
se
cti
on
(c
m2.g
-1)
coherent
com pton
photoelectric
pair production
total
Graphite - Z = 6Graphite - Z = 6
Photon cross sections
JUAS 2010 – P. Berkvens, Radiation & Safety
11/95
1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05
energy (MeV)
cro
ss
se
cti
on
(c
m2.g
-1)
coherent
com pton
photoelectric
pair production
total
Lead - Z = 82Lead - Z = 82
Photon cross sections
JUAS 2010 – P. Berkvens, Radiation & Safety
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1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05
energy (MeV)
cro
ss
se
cti
on
(c
m2.g
-1)
coherent
com pton
photoelectric
pair production
total
K L M N
photo-electron
incoming X-ray
E
E0
E = E – E0
K L M N
E2
E1 E0
E = E0 – E1 = K
E = E0 – E2 = K
The K lines
K L M NE2
E1
E3
E = E1 – E2 = L
E = E1 – E3
= L
The L lines
K L M N
E2
E1
E3
E = E1 – E2 – E3
Auger-electron
Auger electron
Photo-electric effect
JUAS 2010 – P. Berkvens, Radiation & Safety
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scattered photon
compton electronenergy = E0 - Ec
primary photonenergy E0
cos1cm
E1
EE
20
0
0c
energy Ec
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
0 30 60 90 120 150 180
(degrees)
Ec (
Me
V)
50 keV
100 keV
500 keV
1 MeV
10 MeV
100 MeV
1.E-03
1.E-02
1.E-01
1.E+00
0 30 60 90 120 150 180
(degrees)
d/d
(r e
2 x
cm
2 /
ele
ctr
on
)
50 keV
100 keV
500 keV
1 MeV
10 MeV
100 MeV
d/d (re2 x cm2 / electron)Ec (MeV)
Compton scattering
1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05
energy (MeV)
cro
ss
se
cti
on
(c
m2.g
-1)
coherent
com pton
photoelectric
pair production
total
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nucleus Z2
threshold: 1.022 MeV
electron Zthreshold: 2.044 MeV
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.2 0.4 0.6 0.8 1
E/k
rela
tiv
e p
rob
ab
ilit
y
Pair production
1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05
energy (MeV)
cro
ss
se
cti
on
(c
m2.g
-1)
coherent
com pton
photoelectric
pair production
total
JUAS 2010 – P. Berkvens, Radiation & Safety
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Interaction of photons with matterMacroscopic description - Attenuation factors
The mass attenuation coefficient /:
units: cm2.g-1
The linear attenuation coefficient :
units: cm-1
The conversion factor from (barns.atom-1) to / (cm2.g-1):
dl
dN
N
1
dl
dN
N
1
A
N10 A24
0
0 .1
0 .2
0 .3
0 .4
0 .5
0 .6
0 .7
0 .8
0 .9
1
0 1 2 3 4 5 6 7 8 9 1 0
d (cm)d (g.cm-2)
N)(
0
)(0
2
cmgd
cmd
eNN
eNN
JUAS 2010 – P. Berkvens, Radiation & Safety
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-5
-4
-3
-2
-1
0
1
2
3
4
5
0 5 10 15
cm
cm
photon
electron
positron
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
0 1 2 3 4 5
cm
cm
one 500 MeV electron interacting with lead target
cm
Electromagnetic cascade
JUAS 2010 – P. Berkvens, Radiation & Safety
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-10
-8
-6
-4
-2
0
2
4
6
8
10
0 5 10 15 20
cm
cm
photon
electron
positron
one 6 GeV electron interacting with lead target
cm
Electromagnetic cascade
-0.1
0
0.1
0.8 1 1.2 1.4 1.6 1.8 2
cm
cm
JUAS 2010 – P. Berkvens, Radiation & Safety
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0
10
20
30
40
50
60
70
80
10 20 30 40
Energy [MeV]
Cro
ss-s
ectio
n [m
barn
]
Giant resonance
55Mn(γ, n)54Mn
1.E-06
1.E-05
1.E-04
1.E-03
1.E-02
10 100 1000
energy (MeV)
cro
ss
-se
cti
on
(c
m-1)
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1 10 100 1000
energy (MeV)
cros
s-se
ctio
n (m
barn
)
Quasi-deuteron
d
AvQD A
N
A
ZZA
γ(d,p)nγ(d,p)n
Photo-pion
ee-60/E-60/E γ(d,p)nγ(d,p)n
Photonuclear reactions
Neutron production
photonuclear reactions
JUAS 2010 – P. Berkvens, Radiation & Safety
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1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
0 5 10 15 20
energy (MeV)n
um
ber
of n
eutr
on
s
Example: neutron spectrum produced by 600 MeV electrons on Cu target
Giant resonance
Quasi-deuteronPhoto-pion
1.E-06
1.E-05
1.E-04
1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E+00 1.E+01 1.E+02 1.E+03
energy (MeV)
nu
mb
er
of
ne
utr
on
s
Photonuclear reactions
Neutron production
JUAS 2010 – P. Berkvens, Radiation & Safety
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1. elastic scattering• compound elastic scattering• potential scattering
2. inelastic scattering (n,n’)
3. other inelastic reactions: (n,p), (n,), …
4. absorption reactions• radiative capture• charged particle reactions
5. direct reactions: spallation
The physical processes
Interaction of neutrons with matter
JUAS 2010 – P. Berkvens, Radiation & Safety
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etc.
Inelasticgamma-ray
ZA + neutron
etc.
ZA+1
Capturegamma-rays
Compoundinelastic scattering
Compoundelastic scattering
Compoundnucleus
formation
EC
B
virtualenergy
Compound nucleus formation
target nucleus ZA
neutronenergy = EC
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Example 1: iron
1.E-04
1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08
energy (eV)
cro
ss
se
cti
on
(b
arn
)
total
elastic
capture
inelastic
Neutron cross sections
etc.
Inelasticgamma-ray
ZA + neutron
etc.
ZA+1
Capturegamma-rays
Compoundinelastic scattering
Compoundelastic scattering
Compoundnucleus
formation
EC
B
virtualenergy
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1.E-04
1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08
en ergy (eV)
cro
ss
se
cti
on
(b
arn
)
total
elastic
captu re
in elastic
Example 2: cadmium
Neutron cross sections
etc.
Inelasticgamma-ray
ZA + neutron
etc.
ZA+1
Capturegamma-rays
Compoundinelastic scattering
Compoundelastic scattering
Compoundnucleus
formation
EC
B
virtualenergy
JUAS 2010 – P. Berkvens, Radiation & Safety
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1.E-05
1.E-04
1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08
energy (eV)
cro
ss
se
cti
on
(b
arn
)
total
elastic
capture
Example 3: hydrogen
Neutron cross sections
etc.
Inelasticgamma-ray
ZA + neutron
etc.
ZA+1
Capturegamma-rays
Compoundinelastic scattering
Compoundelastic scattering
Compoundnucleus
formation
EC
B
virtualenergy
JUAS 2010 – P. Berkvens, Radiation & Safety
25/95
1.E-05
1.E-04
1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08
energy (eV)
cro
ss
se
cti
on
(b
arn
)
total
elastic
capture
inelastic
(n,alpha)
Example 4: boron
Neutron cross sections
etc.
Inelasticgamma-ray
ZA + neutron
etc.
ZA+1
Capturegamma-rays
Compoundinelastic scattering
Compoundelastic scattering
Compoundnucleus
formation
EC
B
virtualenergy
JUAS 2010 – P. Berkvens, Radiation & Safety
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1.E-04
1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08
energy (eV)
cro
ss
se
cti
on
(b
arn
)
total
elastic
capture
inelastic
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03
proton energy (GeV)
no
ne
las
tic
cro
ss
se
cti
on
(b
)
C
Al
Fe
Cu
W
Pb Example: iron
Neutron cross sections
neutron energy (GeV)
inelastic cross section (barn)
JUAS 2010 – P. Berkvens, Radiation & Safety
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target nucleus
initial neutronenergy = E0
recoiling nucleus
scattered neutronenergy = E1
00
2
imummin,1 EE1A
1AE
0E12
1E
Minimum energy of scattered neutron:
Average energy loss per collision:
target E1,minimum
Hydrogen
(A=1)
0 0.5 E0
Iron(A=56)
0.93 E0 0.034 E0
Lead(A=207)
0.98 E0 0.0096
E0
E
Interaction of neutrons with matter
Elastic scattering
JUAS 2010 – P. Berkvens, Radiation & Safety
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1. ionisation2. inelastic proton-nucleus scattering
spallation
The physical processes
Interaction of protons with matter
JUAS 2010 – P. Berkvens, Radiation & Safety
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1.E+00
1.E+01
1.E+02
1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05
AlFe
Pb
minimum ionising particle
Proton ionisation loss – Stopping power
stopping power (MeV.g-1.cm2)
proton energy (MeV)
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1,E-05
1,E-04
1,E-03
1,E-02
1,E-01
1,E+00
1,E+01
1,E+02
1,E+03
1,E+04
1,E-03 1,E-02 1,E-01 1,E+00 1,E+01 1,E+02 1,E+03 1,E+04
energy (MeV)
CS
DA
ra
ng
e (
g.c
m-2
)
electron
proton
Comparison CSDA range of protons and electrons in iron
JUAS 2010 – P. Berkvens, Radiation & Safety
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p
pn
n
n
intra-nuclear cascadeintra-nuclear cascade
n
d
incident proton(GeV range)
evaporationevaporation
Inelastic proton – nucleus scattering
Spallation reaction
JUAS 2010 – P. Berkvens, Radiation & Safety
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0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03
proton energy (GeV)
no
ne
las
tic
cro
ss
se
cti
on
(b
)
C
Al
Fe
Cu
W
Pb
.042.0 7.0 barnAinel E > 1 GeV
Inelastic proton – nucleus scattering
Spallation reactionInelastic cross section
JUAS 2010 – P. Berkvens, Radiation & Safety
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1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E+00 1.E+01 1.E+02 1.E+03 1.E+04
proton energy (MeV)
ine
las
tic
pro
ba
bilt
y (
%)
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
ran
ge
(c
m)
concreteC
Al
FeP
Cu
W
Cconcrete
AlW
PbFe
Cu
Comparison ionisation energy loss and inelastic scattering
E > 1 GeV: 100 % probability for spallation reaction
Inelastic proton – nucleus scattering
JUAS 2010 – P. Berkvens, Radiation & Safety
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inter-nuclear cascades
p
pn
n
n
intra-nuclear cascade
fission products
fast inducedfission
n
d
fission products
n
n
(n,n’), (n,xn),(n,) ,… reactions
spallation product , , decay
fissionfission
incident proton(GeV range)
Neutron transport below 20 MeV
evaporation
n
n
n
np
Spallation
JUAS 2010 – P. Berkvens, Radiation & Safety
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Spallation
JUAS 2010 – P. Berkvens, Radiation & Safety
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Radiation and SafetyP. Berkvens
1. radiation physics• interaction of electrons with matter• interaction of photons with matter• interaction of neutrons with matter• interaction of protons with matter
2. radiation protection• definitions• rules
3. radiation fields around accelerators• electron accelerators• proton accelerators• synchrotron radiation facilities
4. induced activity
5. radiation monitors
JUAS 2010 – P. Berkvens, Radiation & Safety
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Biological effects:
Effective dose E-
Ambient dose equivalent H*(d)
Absorbed dose D
dt
dDD
dm
dD
gray (Gy): 1 Gy = 1 J.kg-1
(rad: 1 rad = 0.01 Gy)
2lnT
e)0(N)t(N
)t(Ndt
dN
2/1
t
becquerel (Bq): 1 Bq = 1 s-1
(curie (Ci): 1 Ci = 3.7 1010 Bq)
Activity Fluence F
particles per cm2
1/distance2
Introduction to radiation protection
JUAS 2010 – P. Berkvens, Radiation & Safety
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Unit of equivalent dose: J.kg-1 Special name: sievert (Sv)Old unit: rem (1 Sv = 100 rem)
Tm
TT Ddm
mD
1Organ dose DT
Individual organ,e.g. stomach
RTRRT DwH ,,
R
RTRT DwH ,
Tissue or organ equivalent dose HT,R
Type and energy range of radiation Radiation weighting factor
wR Photons, all energies 1 Electrons and muons, all energies 1 Neutrons
< 10 keV 10 - 100 keV > 100 keV to 2 MeV >2 - 20 MeV > 20 MeV
10 5 10 20 10 5
Protons, energy > 2 MeV 5 Alpha particles, fission fragments, heavy nuclei
20
International Commission on Radiological Protection (ICRP)Protection quantities - ICRP Publication 60 (1991)
JUAS 2010 – P. Berkvens, Radiation & Safety
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T
TT HwE
Effective dose E different organs
Tissue or organ Tissue weighting factor wT Gonads 0.20 Bone marrow (red) 0.12 Colon 0.12 Lung 0.12 Stomach 0.12 Bladder 0.05 Breast 0.05 Liver 0.05 Oesophagus 0.05 Thyroid 0.05 Skin 0.01 Bone surface 0.01 Remainder 0.05
Unit of effective dose: Sv
Dose limits on:• Effective dose E• Tissue or organ equivalent dose HT
International Commission on Radiological Protection (ICRP)Protection quantities - ICRP Publication 60 (1991)
JUAS 2010 – P. Berkvens, Radiation & Safety
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Irradiation Irradiation geometriegeometriess
Antero-posterior(AP)
Rotational(ROT)
Isotropic(ISO)
Lateral(LAT)
Postero-anterior(PA)
International Commission on Radiological Protection (ICRP)Protection quantities - ICRP Publication 60 (1991)
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Basic principlesBasic principles
• Radiation protection measures must guarantee that deterministic radiation damage is avoided. Since deterministic damage appears above a threshold dose, this dose must not be exceeded.
• The probability of stochastic radiation damage, which has no threshold dose according to the dose-effect relationships currently taken as a basis, must not exceed a justifiable size.ICRP Publication 60ICRP Publication 60
• The necessity of justifying each radiation application by its benefits.
• The demand for optimising radiation protection measures:
ALARA principle: As Low As Reasonably Achievable.
• The establishment of individual limits for radiation exposure of people on the basis of a justifiable risk.
International Commission on Radiological Protection (ICRP)Protection quantities - ICRP Publication 60 (1991)
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Application Dose limit Occupational Public
Effective dose 20 mSv per year, averaged over defined periods of 5 years, not
exceeding 50 mSv in any single year
1 mSv in a year
Annual equivalent dose in
The lens of the eye 150 mSv 15 mSv
The skin 500 mSv 50 mSv
The hands and feet 500 mSv - radiation workers 20 mSv .y-1
10 Sv.h-1 *
non-exposed workers 1 mSv .y-1
0.5 Sv .h-1 *
public 1 mSv .y-1
0.11 Sv .h-1 **
* 2000 working hours/year** 8760 hours/year
International Commission on Radiological Protection (ICRP)Protection quantities - ICRP Publication 60 (1991)
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International Commission on Radiological Protection (ICRP)Protection quantities - ICRP Publication 103 (2007)
ICRP 60 ICRP 103
Gonads 0.20 0.08
Bone marrow (red) 0.12 0.12
Colon 0.12 0.12
Lung 0.12 0.12
Stomach 0.12 0.12
Bladder 0.05 0.04
Breast 0.05 0.12
Liver 0.05 0.04
Oesophagus 0.05 0.04
Thyroid 0.05 0.04
Skin 0.01 0.01
Bone surface 0.01 0.01
Brain - 0.01
Salivary gland - 0.01
Remainder 0.05 0.12
Total 1 1
Tissue weighting factor wT
MeV50E,e25.35.2
MeV50EMeV1,e0.170.5
MeV1E,e2.185.2
n6/E04.0ln
n6/E2ln
n6/Eln
2n
2n
2n
ICRP Publication 103-
Radiation weighting factor wR
neutrons
protons: 2
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International Commission on Radiation Units and Measurements ICRU Report 51 (1993)
Protection quantities (ICRP) operational quantities
DQH
Dose equivalent
Unit of dose equivalent: Sv Unrestricted linear energy
transfer
L (keVµm-1)
Quality factor
Q
L < 10 1
10 L 100 0.32 L - 2.2
L > 100 300 / L1/2
d point ofmeasurement
expanded and aligned field
ICRU sphere 30 cm diameter tissue-equivalent sphere:
density 1 g.cm-3
composition by mass: 76.2 % O, 11.1 % C, 10.1 % H and 2.6 % N
Ambient dose equivalent H*(d)
H*(10) (d = 10 mm)
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0.001
0.01
0.1
1
10
1.E-02 1.E-01 1.E+00 1.E+01
Photon energy (MeV)
Sv/G
y
E(AP)K
E(ROT)/K
H*(10)/K
Ratio of effective dose E to air kerma free-in-air (AP and ROT) and ratio of ambient dose equivalent H*(10) to air kerma free-to-air as a function of photon energy.
0.01
0.1
1
1.E-02 1.E-01 1.E+00 1.E+01
Photon energy (MeV)
Sv/
Gy
E(AP)/H*(10)
E(ROT)/H*(10)Ratio of effective dose E (AP
and ROT) to ambient dose equivalent H*(10) as a function
of photon energy.
Comparison between protection quantities (ICRP) and operational quantities (ICRU) – ICRU Report 57 (1998)
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Effective dose E per unit neutron fluence (AP and ROT) and ambient dose equivalent H*(10) per unit neutron fluence as a function of neutron energy.
1
10
100
1000
1.E-09 1.E-07 1.E-05 1.E-03 1.E-01 1.E+01 1.E+03
neutron energy (MeV)
pSv.
cm-2
E(AP)/F
E(ROT)/F
H*(10)/F
0
1
2
1.E-09 1.E-07 1.E-05 1.E-03 1.E-01 1.E+01 1.E+03
neutron energy (MeV)
pSv.
cm-2
E(ROT)/H*(10)
E(AP)/H*(10)
Ratio of effective dose E (AP and ROT) to ambient dose equivalent
H*(10) as a function of neutron energy.
Comparison between protection quantities (ICRP) and operational quantities (ICRU) – ICRU Report 57 (1998)
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Radiation and SafetyP. Berkvens
1. radiation physics• interaction of electrons with matter• interaction of photons with matter• interaction of neutrons with matter• interaction of protons with matter
2. radiation protection• definitions• rules
3. radiation fields around accelerators• electron accelerators• proton accelerators• synchrotron radiation facilities
4. induced activity
5. radiation monitors
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electron accelerators
photons (bremsstrahlung)neutrons
proton accelerators
neutrons
synchrotron radiation facilities
acceleratorsbeamlines
Prompt radiation fields around accelerators
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Examples of neutron spectra
Example 1: calculated neutron spectra for the 1.7 GeV BESSY storage ring (Courtesy of Klaus Ott)
Radiation fields around electron accelerators
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0.0E+00
5.0E+01
1.0E+02
1.5E+02
2.0E+02
E E
1.0E+00 1.0E+01
Neutron Energy (MeV)
Examples of neutron spectra
Example 2: measured neutron spectrum on the roof of the 6 GeV ESRF storage ring (behind 1.2 m concrete shielding)
Radiation fields around electron accelerators
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Type of radiation
Energy range
Estimated % of neutron
flux density
Estimated % of total
dose equivalent
Neutrons < 1 eV < 7 <1
Neutrons 1 eV – 0.7 MeV 70 20
Neutrons 0.7 – 3 MeV 15 35
Neutrons 3 – 7 MeV 7 25
Neutrons 7 – 20 MeV 1.5 5
Neutrons + protons 20 – 100 MeV 1 5
Neutrons + charged particles > 100 MeV 0.5 4
Other particles + gammas - - < 2
7 GeV proton synchrotron NIMROD
Radiation fields around proton accelerators
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Source: Compendium of Neutron Spectra and Detector Responses for Radiation Protection Purposes – Technical Reports Series no. 403 , IAEA, 2001
Examples of neutron spectra
1 MeV
Radiation fields around proton accelerators
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Source: Compendium of Neutron Spectra and Detector Responses for Radiation Protection Purposes – Technical Reports Series no. 403 , IAEA, 2001
Examples of neutron spectra
1 MeV
Radiation fields around proton accelerators
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Source: Compendium of Neutron Spectra and Detector Responses for Radiation Protection Purposes – Technical Reports Series no. 403 , IAEA, 2001
Examples of neutron spectra
1 MeV
Radiation fields around proton accelerators
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i
2
d
H
r
WeFH
i
i
targettarget
incident beamincident beam
dd
rr
H
H : dose equivalent rate, in Sv×h-1 W: primary beam loss rate, in kW
iHF : fluence to (unshielded) dose equivalent conversion factor, in Sv×h-1 (kW×m-2)-1
d: shield wall thickness, in g×cm-2
i: attenuation length for the ith radiation component, in g×cm-2
r: distance from the source to the dose point, in m i: sum over different radiation components
Accelerator shielding
Analytical models
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iHF : fluence to (unshielded) dose equivalent conversion factor
secondary radiation
Sv.h-1.kW-1 at 1 m
at 0 degat 90 deg
bremsstrahlung 300× E(MeV) 50
neutrons < 25 MeV 20 20
neutrons 25 – 100 MeV
- 2.4
neutrons > 100 MeV 9.2 0.72
radiationconcret
e
cmiron lead
bremsstrahlung 21 4.7 2.4
neutrons < 25 MeV 18 16 -
neutrons 25 – 100 MeV
28 - -
neutrons > 100 MeV 43 18 17
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1 10 100 1000
electron energy (MeV)
Sv.h
-1 (k
W.m
-2)-1
forewarddirection
sidewarddirection (90 degrees)
bremsstrahlung
i:attenuation length
Accelerator shielding: electron accelerator
Analytical models
fluence to (unshielded) dose equivalent conversion factor
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Accelerator shielding
Monte-Carlo codesExamples: MCNPX
PENELOPEFLUKAMARS
<0.2 mrem/h
[mSv/h]
[mrem/h]
[mSv/h]
[mrem/h]
[mSv/h]
[mrem/h]Aspect ratio
1:2
Beam dump hall FEE NEH
<0.0025 mrem/h<0.025 mrem/h1rem/h
5kW @
beam
dump
5W @
BYD1
Example: MARS calculation for the electron dump line of the LCLS facility - Courtesy of T. Sanami.
JUAS 2010 – P. Berkvens, Radiation & Safety
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Synchrotron radiation facilities
15 m
ID vessel
optics hutch
front end
concrete wallneutrons
photons
Radiation fieldsAccelerator tunnels:
photons, neutronsBeamlines:
X-rays, photons, neutrons
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Example: ESRF 6 GeV storage ring, continuous beam loss during injection:10 mA, 1 s, 1 Hz, 6 GeV
0.5 mSv/h
1.6 mSv/h
1.2 m ordinary concrete
1 m heavy concrete
Synchrotron radiation facilities
Storage ring shielding
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lead
heavy concrete
lead
heavy concrete0.5 Sv/h
0.5 Sv/hExample: ESRF 6 GeV storage ring, continuous beam loss during injection:10 mA, 1 s, 1 Hz, 6 GeV
Synchrotron radiation facilities
Storage ring shielding
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3 mm Fe
1 mm Fe
1 mm Feplomb
120 cm
0.1
1
10
100
1000
10000
0 5 10 15 20 25 30
mm Pb
Sv.
h-1
6 mrad bend
3 U35
W150
in-vacuum
0,5 Sv.h-1
Synchrotron radiation facilities
Beamline shielding: synchrotron radiation
120 cm
lead
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0
0.1
0.2
0.3
0.4
0.5
20 30 40 50 60 70 80 90
Sv.
h-1
6 mrad bend
3 U35
W150
in-vacuum
angle (degrés)
3 mm Fe
1 mm Fe
1 mm Feplomb
120 cm
Synchrotron radiation facilities
Beamline shielding: synchrotron radiation
120 cm
lead
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3 mm Fe
1 mm Fe
1 mm Feplomb
120 cm
Synchrotron radiation facilities
Beamline shielding: synchrotron radiation
120 cm
lead
1.E-07
1.E-04
1.E-01
1.E+02
1.E+05
1.E+08
1.E+11
1.E+14
1.E+17
1 10 100 1000
energie (keV)
ph/s
/0.0
01E 0 mm
1 mm
5 mm
8 mm
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Synchrotron radiation facilities
Beamline shielding: gas-bremsstrahlung
,LIpEdx
dECP e
LIEP e 22
Gas-bremsstrahlung power: electron stopping powerpressure in straight sectionelectron beam intensitylength of straight section
IEp
EEdx
dE
e
ee
The shielding requirements for the optics hutches of 3rd generation insertion device beamlines are largely determined by gas-bremsstrahlung (and photo-neutrons).
ESRF SRS Diamond Soleil
Energy (GeV) 6 2 3 2.75
Current (mA) 200 250 500 500
Straight section (m) 15 3.82 15.75 18.75 7.7 12.4 18.5
Bremsstrahlung power
(normalised to ESRF)
1 0.044 1.64 1.95 0.67 1.09 1.62
IEp
EEdx
dE
e
ee
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Synchrotron radiation facilities
Beamline shielding: gas-bremsstrahlung
fentes primaires en Cu miroir en Si
écran en Pb, épaisseur 2 cm, 20 x 20 cm2
monochromateur avec arrêtoir en W,épaisseur 10 cm, 6 cm
120 cm
50 cm 100 cm 150 cm 200 cm
1000 cm
primary slits (Cu)mirror (Si)
Pb screen, 2 cm, 20 x 20 cm2
monochromator + W beamstop 10 cm, 6 cm
fentes primaires en Cu miroir en Si
écran en Pb, épaisseur 2 cm, 20 x 20 cm2
monochromateur avec arrêtoir en W,épaisseur 10 cm, 6 cm
120 cm
50 cm 100 cm 150 cm 200 cm
1000 cm
distance le long de l’axe du faisceau (cm)
début de la cabine
débit de dose (Sv.h-1)
1.E-02
1.E-01
1.E+00
-200 0 200 400 600 800 1000
effective dose rate (Sv.h-1)
distance along hutch (cm)
distance le long de l’axe du faisceau (cm)
début de la cabine
débit de dose (Sv.h-1)
1.E-02
1.E-01
1.E+00
-200 0 200 400 600 800 1000
photons
neutrons
Example: typical ESRF Optics Hutch - Sidewall: 3 cm Pb6 GeV, 200 mA, average pressure straight section 5 × 10-9 mbar
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1.E-07
1.E-06
1.E-05
1.E-04
0.01 0.1 1 10 100On-axis bremsstrahlung measurements during initial conditioning of ESRF 5 m long, 8 mm internal height NEG-coated extruded aluminium ID vessels
factor 2.5
2 orders of magnitude
electron dose (Ah)
Gy/h/mA2
23 days continuous operation at 185 mA
Synchrotron radiation facilities
Beamline shielding: gas-bremsstrahlung
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0100200300
0 10 20 30 40 50
stored beam current (mA)
time (days)
1.E-10
1.E-09
1.E-08
1.E-07
0 10 20 30 40 50
1 × 10-7
1 × 10-8
1 × 10-9
1 × 10-10
penning gauge no. 1 (mbar)
Synchrotron radiation facilities
Beamline shielding: gas-bremsstrahlung
Example: ID12 beamline at ESRF
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0.0E+00
5.0E+04
1.0E+05
1.5E+05
2.0E+05
2.5E+05
0 10 20 30 40 50
0100200300
0 10 20 30 40 50
stored beam current during user operation (mA)
time (days)
2 × 105
1.5 × 105
5 × 104
1 × 105
2.5 × 105
0
∫I×ppenning 1.dt (mA×10-9 mbar × h)
Synchrotron radiation facilities
Beamline shielding: gas-bremsstrahlung
Example: ID12 beamline at ESRF
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0.0E+00
5.0E+04
1.0E+05
1.5E+05
2.0E+05
2.5E+05
0 10 20 30 40 50
0
10
20
30
40
50
0100200300
0 10 20 30 40 50
stored beam current during user operation (mA)
time (days)
∫I×ppenning 1.dt (mA×10-9 mbar × h) ambient dose equivalent (Sv)
(× 0.55)
photons
neutrons
2 × 105
1.5 × 105
5 × 104
1 × 105
2.5 × 105
0
Synchrotron radiation facilities
Beamline shielding: gas-bremsstrahlung
Example: ID12 beamline at ESRF
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distance along beam axis (cm)
ambient dose equivalent rate (Sv/h)
0.00
0.01
0.02
0.03
0.04
0.05
0.06
0 500 1000 1500
photons
neutrons
total
Series4
Series5
Series6
Series7
calculatedphotonsneutronstotal
0.00
0.01
0.02
0.03
0.04
0.05
0.06
0 500 1000 1500
photons
neutrons
total
Series4
Series5
Series6
Series7
measuredphotonsneutronstotal
average pressure in straight section: 1 × 10-9 mbarstored beam current: 200 mA
0.00
0.02
0.04
0.06
0.08
0.10
0 200 400 600 800 1000
0.5 Sv/h:300 mA, 3.8 × 10-9 mbar
Synchrotron radiation facilities
Beamline shielding: gas-bremsstrahlung
Example: ID12 beamline at ESRF
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Radiation and SafetyP. Berkvens
1. radiation physics• interaction of electrons with matter• interaction of photons with matter• interaction of neutrons with matter• interaction of protons with matter
2. radiation protection• definitions• rules
3. radiation fields around accelerators• electron accelerators• proton accelerators• synchrotron radiation facilities
4. induced activity
5. radiation monitors
JUAS 2010 – P. Berkvens, Radiation & Safety
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• thermal and slow neutron reactions• medium energy neutron reactions• nuclear reactions at high energy (spallation)• photonuclear reactions
• radiation remains after accelerator switched off• work permits for people entering tunnels• radiation protection: personnel and environment• management of activated accelerator components• decommissioning of facilities
relatively insensitive to activation
moderately susceptible to activation
highly susceptible to activation
fissionable
ordinary concrete, Pb, Al, wood, plastics
Fe (steel, ferrites), Cu Stainless steel, W, Ta, Zn, Au, Mn, Co, Ni
U, Pu, Th
Induced activity
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Number of neutrons
Number of protons
Induced activity
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0
10
20
30
40
50
60
70
80
10 15 20 25 30 35 40
energy [MeV]
cro
ss
se
cti
on
[m
ba
rn]
55Mn(, n)54Mn photonuclear reactions(,n), (,p), (,np), …
1.E-06
1.E-05
1.E-04
1.E-03
1.E-02
10 100 1000
energy [MeV]
cro
ss s
ecti
on
[1/
cm]
1.E-06
1.E-05
1.E-04
1.E-03
1.E-02
10 100 1000
energy [MeV]
cro
ss s
ecti
on
[1/
cm]
Activation from electron beam
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Activation from electron beam
inelastic reactions (n,p), (n,), …
0.00
0.01
0.01
0.02
0.02
0.03
0.03
0.04
0.04
0 5 10 15 20
energy (MeV)
cro
ss s
ect
ion
(b
arn
)
63Cu(n,)60Co0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0 5 10 15 20
energy (MeV)
cro
ss s
ect
ion
(b
arn
)
60Ni(n,p)60Co
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1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08
energy (eV)
cro
ss
se
cti
on
(b
arn
)
Activation from electron beam
radiative capture
151Eu(n,)152Eu
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1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
0.001 0.01 0.1 1 10
cooling time (y)
spec
ific
activ
ity (
Bq.
g-1)
51Cr
54Mn
52Mn
56Mn
60Co
48V
46Sc
44mSc
59Fe
57Co
58Co
48Sc43K
48Cr
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
0.001 0.01 0.1 1 10
cooling time (y)
spec
ific
activ
ity (
Bq.
g-1)
51Cr
54Mn
52Mn
56Mn
60Co
48V
46Sc
44mSc
59Fe
57Co
58Co
48Sc43K
48Cr
Example: cooling down curve of irradiated steel
Activation from electron beam
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Stainless steel vessel ESRF
1
10
100
1000
10000
0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900
Energy (ke V)
Co
un
ts
57Co 51
Cr +,-58
Co54
Mn
46Sc
52Mn
56Co
48V
Activation from electron beam
JUAS 2010 – P. Berkvens, Radiation & Safety
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inter-nuclear cascades
p
pn
n
n
intra-nuclear cascade
fission products
fast inducedfission
n
d
fission products
n
n
(n,n’), (n,xn),(n,) ,… reactions
spallation product , , decay
fissionfission
incident proton(GeV range)
Neutron transport below 20 MeV
evaporation
n
n
n
np
Activation from proton beam
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Isotope Half-life Decay
mode fSv.h-1.Bq-1 at 1
m 7Be 53 d EC 7.8 11C 20 min + 140 18F 1.8 h + 132
22Na 2.6 y + 298 24Na 15 h + 560 46Sc 84 d + 283 48Sc 1.8 d + 455 48V 16 d + 397 51Cr 28 d EC 4.3 52Mn 5.7 d + 326 54Mn 303 d EC 114 56Co 77 d + 350 60Co 5.3 y + 340 65Zn 245 d EC 76
Principal radioactive isotopes produced in accelerator structures by spallation reactions
Activation from proton beam
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Parent isotope
Natural (%)
(barn)
Active isotope
Half-life
fSv.h-1 at 1m per Bq per g
23Na 100 0.53 24Na 15 h 560 7.7 40Ar 99.6 0.61 41Ar 1.8 h 150 1.4 44Ca 2.0 0.70 45Ca 165 h - - 50Cr 4.3 17 51Cr 28 d 4 0.04 55Mn 100 13 56Mn 2.6 h 2520 35 59Co 100 37 60Co 5.3 y 340 128 63Cu 69 4.5 64Cu 13 h 28 0.84 64Zn 49 0.46 65Zn 245 d 76 0.16 121Sb 57 6.1 122Sb 2.8 d 60 1.0 123Sb 43 3.3 124Sb 60 d 200 1.4 133Cs 100 31 134Cs 2.1 y 116 17 151Eu 48 8700 152Eu 12 y 45 750 153Eu 52 320 154Eu 8 y 286 190 186W 28 40 187W 1d 73 2.6
Most important isotopes near high energy particle accelerators formed by thermal neutron capture
Activation from proton beam
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Radiation and SafetyP. Berkvens
1. radiation physics• interaction of electrons with matter• interaction of photons with matter• interaction of neutrons with matter• interaction of protons with matter
2. radiation protection• definitions• rules
3. radiation fields around accelerators• electron accelerators• proton accelerators• synchrotron radiation facilities
4. induced activity
5. radiation monitors
JUAS 2010 – P. Berkvens, Radiation & Safety
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0
50
100
150
200
250
0 1 0 2 0 3 0 4 0 5 0
mA
0.1
1.0
10.0
0 10 20 30 40 50
days since 18/01/02
do
se
ra
te (
S
v.h-1
)
Example: photon dose rate measurement around ESRF storage ring
Radiation monitoring
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I
w H2 He O2 Ar Air
electrons 36.3 eV 41 eV 31 eV 26.4 eV 34 eV
alphas 36.5 eV 44 eV 32.4 eV 26.4 eV 35.3 eV
VI
V
ionisation chamber
proportional counter
Geiger-Müller counter
IVe
w
dt
dD
dt
dN
V
w
dt
dD
w
EN
gasgas
pairs
gasgas
pairs
EE
Radiation monitoring
Gas-filled detectors
JUAS 2010 – P. Berkvens, Radiation & Safety
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Radiation monitoring
Ionisation chambers
JUAS 2010 – P. Berkvens, Radiation & Safety
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Radiation monitoring
Proportional counter
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Radiation monitoring
Geiger - Müller counter
JUAS 2010 – P. Berkvens, Radiation & Safety
88/95
Radiation monitoring
Neutron monitors
Example: neutron spectrum around the 1.7 GeV BESSY storage ring (Courtesy of Klaus Ott)
JUAS 2010 – P. Berkvens, Radiation & Safety
89/95
%)6(MeV792.2Li
%)94(MeV310.2LiBn
keV765HpHen
73
7310
5
33
3He-filled proportional counter:
BF3 counter:
Polyethylene moderator
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08
energy (eV)
cros
s se
ctio
n (b
arn)
3He(n,p)3H33He(n,p)He(n,p)33HH
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08
energy (eV)
cros
s se
ctio
n (b
arn)
3He(n,p)3H33He(n,p)He(n,p)33HH
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08
energy (eV)
cros
s se
ctio
n (b
arn)
10B(n,)7Li1010B(n,B(n,))77LiLi
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08
energy (eV)
cros
s se
ctio
n (b
arn)
10B(n,)7Li1010B(n,B(n,))77LiLi
Radiation monitoring
Moderated neutron monitors
JUAS 2010 – P. Berkvens, Radiation & Safety
90/95
0
0 .2
0 .4
0 .6
0 .8
1
1 .2
1 .E-4 1 .E-3 1 .E-2 1 .E-1 1 .E+0 1 .E+1 1 .E+2
e n e rg y (Me V)
µS
v .
cm
2 (
rela
tiv
e u
nit
s)
ICRP
CRAMAL-31
Radiation monitoring
Moderated neutron monitors
JUAS 2010 – P. Berkvens, Radiation & Safety
91/95
Radiation monitoring
Moderated neutron monitors
Neutron response enhancement using lead-shell in moderator type counters
BertholdLB-6411
JUAS 2010 – P. Berkvens, Radiation & Safety
92/95
expanded bubble(~ 0.1 – 0.6 mm)
superheated drop(20 – 100 m)
neutron
chargedparticle
vapour embryo< 0.1 m
Radiation monitoring
Superheated emulsions
0
8
0 3
temperature
pre
ssu
re
solid
liquid
vapour
superheating
over-expansion
JUAS 2010 – P. Berkvens, Radiation & Safety
93/95
Thermal neutrons: OK
Epithermal neutrons: not important
0.1 – 10 MeV: OK
Under-read > 10 MeV
Energy response of SDD100 vials (dichlorodifluoromethane)
Radiation monitoring
Superheated emulsions
JUAS 2010 – P. Berkvens, Radiation & Safety
94/95
Radiation monitoring
Superheated emulsions
effect of lead moderator
JUAS 2010 – P. Berkvens, Radiation & Safety
95/95
Acoustic bubble counting
Model ABC1260Framework Scientificwww.framesci.com
Radiation monitoring
Superheated emulsions