Transcript MEASUREMENTS IN QUASI-MONOENERGETIC NEUTRON …

CALIBRATION OF THE UAB PADC
BASED NEUTRON DOSEMETER
Measurements in quasi-monoenergetic
neutron beams at the EC-IRMM Van
der Graaf accelerator
C. Domingo. M.J. García-Fusté. K. Amgarou. E. Morales and J. Castelo
Grup de Física de les Radiacions
24th International Conference on
Nuclear Tracks in Solids
Overview
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1. The UAB PADC neutron dosimetry
system
2. Dosemeter response
3. Measurements at EC-IRMM Van der
Graaf facility
4. Results
5. Conclusions
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The UAB PADC neutron
dosimetric system
Dosemeter configuration
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PADC neutron detector:
CR-39
Converters:
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Makrofol (300 μm)
6 cm
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Rich in H. fast neutron
interaction
Nylon rich in N. high
cross section for thermal
neutrons
Polyethylene (3 mm)
Nylon (100 μm)
CR-39 (500 μm)
Methacrylate (5 mm)
6 cm
Wrapped in Climafol
pouches
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The UAB PADC neutron
dosimetric system
Process after irradiation
6 cm
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Cutting
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Electrochemical
Etching
6 cm
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The UAB PADC neutron
dosimetric system
Track density determination
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Typical track
diameters of 100 μm
Semi-automatic
counting system
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Sony camera
ImageJ analysis
software
Scanned area:
0.53 cm2
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Dosemeter response
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Expected behaviour
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NRPB Report W25
R.J. Tanner et al.. Radit. Meas. 34 (2001) 457-461
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Dosemeter response
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Calibration with ISO neutron sources and
realistic fields at IRSN Cadarache (France)
Source
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Type of
field
Mean
Energy
RΦ
(neutron-1)
RHp(10)
(cm-2·mSv1)
241Am-Be
ISO
4.15 MeV
(1.82 ± 0.13)×10-4
450 ± 33
Bare 252Cf
ISO
2.13 MeV
(2.01 ± 0.13)×10-4
591 ± 39
(252Cf + D2O)/Cd
ISO
539 keV
(5.55 ± 0.27)×10-5
499 ± 24
ISO
539 keV
(5.17 ± 0.23)×10-5
518 ± 23
Realistic
79 keV
252Cf
+ D2O
SIGMA
(1.422 ± 0.064)×10-5 575 ± 26
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Fluence response, R
(neutron
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-1
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Dosemeter fluence response
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Neutron energy (eV)
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Dosemeter Hp(10.0º) response
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(cm ·mSv )
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500
H p (10)
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Dose response, R
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Neutron energy (eV)
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Measurements at EC-IRMM Van
der Graaf facility
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EC NUDAME
program
Quasi-monoenergetic
neutron fields from
few hundreds keV to
20 MeV
New energies for
dosemeter calibration
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Measurements at EC-IRMM Van
der Graaf facility
Neutron beams and methods
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Neutron energies used:
300 keV. 800 keV.
7.5 MeV and 16 MeV
Methacrylate phantom
used
BSS spectrometry for
determination of neutron
spectrum and H*(10)
reference value at each
irradiation point
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Measurements at EC-IRMM Van
der Graaf facility
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Results
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4 dosemeters per energy
Background determined with 4 extra non-irradiated dosemeters
Nominal
Energy
Target
Mean Energy
with BSS
RΦ
RHp(10)
(neutron-1)
(cm-2·mSv-1)
300 keV
T(p.n)3He
269 keV
(4.13 ± 0.53)×10-5
211 ± 27
800 keV
T(p.n)3He
662 keV
(1.24 ± 0.16)×10-4
371 ± 48
7.5 MeV
D(d.n)3He
7.53 MeV
(8.95 ± 0.16)×10-5
128 ± 24
16 MeV
T(d.n)4He
12.66 MeV
(1.19 ± 0.15)×10-4
198 ± 25
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Results – Fluence response
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Fluence response, R
(neutron
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-1
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IRMM-EC Van der Graaf
Cadarache
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Neutron energy (eV)
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Results – Dose response
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(cm ·mSv )
600
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500
H p (10)
400
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Dose response, R
300
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IRMM-EC Van der Graaf
Cadarache
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10
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Neutron energy (eV)
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Conclusions
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The knowledge of the dosemeter response
have been expanded with new energies
An important decrease of the response in
the epithermal region has been confirmed
… to be done
 New values at thermal and low epithermal
regions should be obtained to complete the
dosemeter response function
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Thanks for your attention!
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