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Track etch based LET spectrometry in beams of neutrons with energies from 0.2 to 200 MeV. Brabcová Kateřina Spurn ý F ranti šek Jadrníčková Iva Department o f Radiation Dosimetry, Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Prague , [email protected]. content. - PowerPoint PPT Presentation
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Track etch based LET spectrometry in beams of neutrons with energies from 0.2 to 200 MeV
Brabcová Kateřina
Spurný František
Jadrníčková Iva
Department of Radiation Dosimetry, Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Prague, [email protected]
content
• briefly about neutron dosimetry
• track etched detectors (TED)
• conditions of our experiments
• results
• conclusion
about neutron dosimetry
• indirectly ionizing radiation, energy transferred through the kinetic energy of secondary charged particles
• large spectrum of the secondary particles created in detector or around
• LET spectra should be known
experimental methods of LET spectrometry
• tissue-equivalent proportional counters, bubble detectors, nuclear emulsions,
• in case of long exposure, limitation in weight and dimension, presence of intense low LET radiation :
track etched based LET spectrometers
TED generally• mostly polyallyldiglycolcarbonate C12H18O • evaluation by etching • measuring of track parameters
• calibration
B
T
V
VV
etch rate of damaged material
etch rate of unaffected material
)(VfLET
etch ratio
• polyallyldiglycolcarbonate C12H18O Page, 0.5 mm (Page Moulgings Ltd, England)
Tastrak, 0.5 mm (Track Analysis Systems Ltd, Bristol)
• evaluation by etching 5 M NaOH at 70oC for 18 hours
• measuring of track parameters automatic optical image analyzer LUCIA G
• calibration
our TED
calibration of TED
• heavy charged particle beams12C – 84Kr
LET from 7.5 to 600 keV/μm
• performed in cooperation withHIMAC (NIRS Chiba, Japan) in the frame of ICCHIBAN
programs – ICCHIBAN 2, 4, 6, and 8
NASA Space Radiation Laboratory (Brookhaven National Laboratory) in the frame of ICCHIBAN BNL
Nuclotron of the Laboratory of High Energies, JINR, Dubna
experiment EC-JRC
• done at the Van de Graaff facility at the EC-JRC, Geel
• quasi mono-energetic neutron beams produced by protons and deuterons
• 7 different energies of neutron beams from 200 keV to 20 MeV
• reference values – neutron fluences and neutron spectra, ambient dose equivalent H*(10)
experiment iThemba
• done in iThemba laboratory, Cape Town
• quasi mono-energetic neutron beams produced by deuterons and Li targets
• 2 energies of neutron beams – 100 and 200 MeV
• reference values – neutron fluences and neutron spectra, ambient dose equivalent H*(10)
experiment EC-JRC
Page - LET distribution of H
0.00
0.05
0.10
0.15
0.20
0.25
0.30
10 100 1000
LET [keV.μm-1]
LE
T*H
0.2 MeV
?
experiment EC-JRC
Page - LET distribution of H
0.00
0.05
0.10
0.15
0.20
0.25
0.30
10 100 1000
LET [keV.μm-1]
LE
T*H 0.2 MeV
0.5 MeV
recoil protons up to 100 keV.μm-1
experiment EC-JRC
Page - LET distribution of H
0.00
0.05
0.10
0.15
0.20
0.25
0.30
10 100 1000
LET [keV.μm-1]
LE
T*H
0.2 MeV
0.5 MeV
1 MeV
experiment EC-JRC
Page - LET distribution of H
0.00
0.05
0.10
0.15
0.20
0.25
0.30
10 100 1000
LET [keV.μm-1]
LE
T*H
0.2 MeV
0.5 MeV
1 MeV
3.5 MeV
experiment EC-JRC
Page - LET distribution of H
0.00
0.05
0.10
0.15
0.20
0.25
0.30
10 100 1000
LET [keV.μm-1]
LE
T*H
0.2 MeV
0.5 MeV
1 MeV
3.5 MeV
7 MeV
(n,x)X
experiment EC-JRC
Page - LET distribution of H
0.00
0.05
0.10
0.15
0.20
0.25
0.30
10 100 1000
LET [keV.μm-1]
LE
T*H
0.2 MeV
0.5 MeV
1 MeV
3.5 MeV
7 MeV
16 MeV
experiment EC-JRC
Page - LET distribution of H
0.00
0.05
0.10
0.15
0.20
0.25
0.30
10 100 1000
LET [keV.μm-1]
LE
T*H
0.2 MeV
0.5 MeV
1 MeV
3.5 MeV
7 MeV
16 MeV
20 MeV
experiment EC-JRC
0.5 mm Tastrak - LET distribution of H
0.00
0.05
0.10
0.15
0.20
0.25
10 100 1000
LET [keV.μm-1]
LE
T*H
0.2 MeV
experiment EC-JRC
0.5 mm Tastrak - LET distribution of H
0.00
0.05
0.10
0.15
0.20
0.25
10 100 1000
LET [keV.μm-1]
LE
T*H 0.2 MeV
0.5 MeV
recoil protons up to 100 keV.μm-1
experiment EC-JRC
0.5 mm Tastrak - LET distribution of H
0.00
0.05
0.10
0.15
0.20
0.25
10 100 1000
LET [keV.μm-1]
LE
T*H
0.2 MeV
0.5 MeV
1 MeV
experiment EC-JRC
0.5 mm Tastrak - LET distribution of H
0.00
0.05
0.10
0.15
0.20
0.25
10 100 1000
LET [keV.μm-1]
LE
T*H
0.2 MeV
0.5 MeV
1 MeV
3.5 MeV
experiment EC-JRC
0.5 mm Tastrak - LET distribution of H
0.00
0.05
0.10
0.15
0.20
0.25
10 100 1000
LET [keV.μm-1]
LE
T*H
0.2 MeV
0.5 MeV
1 MeV
3.5 MeV
7 MeV
(n,x)X
experiment EC-JRC
0.5 mm Tastrak - LET distribution of H
0.00
0.05
0.10
0.15
0.20
0.25
10 100 1000
LET [keV.μm-1]
LE
T*H
0.2 MeV
0.5 MeV
1 MeV
3.5 MeV
7 MeV
16 MeV
experiment EC-JRC
0.5 mm Tastrak - LET distribution of H
0.00
0.05
0.10
0.15
0.20
0.25
10 100 1000
LET [keV.μm-1]
LE
T*H
0.2 MeV
0.5 MeV
1 MeV
3.5 MeV
7 MeV
16 MeV
20 MeV
100 MeV
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
10 100 1000
LET [keV.μm-1]
LE
T*H
Page
0.5 mm Tastrak
experiment iThemba
100 MeV and 200 MeV
0
0,02
0,04
0,06
0,08
0,1
0,12
0,14
0,16
0,18
0,2
10 100 1000
LET [keV.μm-1]
LE
T*H
Page 100 meV
Tastrak 100 MeV
Page 200 MeV
Tastrak 200 MeV
experiment iThemba
dosimetric characteristic
HLET = ∫ (dN / dLET) . LET . Q(LET) . dLET
dose equivalent due to registered particles
dN/dLET – number of tracks N in a LET interval dLET
Q(LET) – ICRP 60 quality factor
H*(10)
ambient dose equivalent (reference value)
response of detectors
0.1
1
10
0.1 1 10 100 1000
neutron energy in MeV
rati
o H
LE
T/H
*(1
0) Page
T0,5
conclusion
• TED provides new information about neutron energy transfer to the matter
• dose equivalent of secondary particles is lower than ambient dose equivalent H*(10)
• intention of futher studiesexperiment with another neutron energies
deal with unexpected values of 200 keV and 7 MeV
Acknowledgements• Part of study has been realised in the frame of
ESA DOBIES project. We are obliged to Filip Vanhavere (SCK MOL, Belgium) for the coordination of the project, and to ESA Prodex Office for financial assistance.
• Many of results presented in this contribution were obtained by using the results of ICCHIBAN research project using heavy Ions at HIMAC-NIRS, NSRL–BNL, nuclotron JINR Dubna. We are much obliged to the staff of all laboratories and, particularly, to organizers of the run, Y. Uchihori, N. Yasuda, J. Miller, E.R. Benton, A.G. Molokanov, and V.P. Bamblevski† for their help.
• Studies were also partially supported through the grant No. 202/04/0795 of the GA CR and the IRP AV0Z10480505.
Thank you!
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