Grup de Física de les Radiacions24th International Conference on

Nuclear Tracks in Solids

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

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Overview

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

PADC neutron detector: CR-39

Converters: Rich in H. fast neutron

interaction Nylon rich in N. high

cross section for thermal neutrons

Wrapped in Climafol pouches

Dosemeter configuration

6 cm

6 cm

Methacrylate (5 mm)

Makrofol (300 μm)

Polyethylene (3 mm)

CR-39 (500 μm)

Nylon (100 μm)

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The UAB PADC neutron dosimetric system

Process after irradiation

6 cm

6 c

m

Cutting

Electrochemical Etching

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The UAB PADC neutron dosimetric system

Typical track diameters of 100 μm

Semi-automatic counting system Sony camera ImageJ analysis

software Scanned area: 0.53 cm2

Track density determination

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Dosemeter response Expected behaviour

NRPB Report W25 R.J. Tanner et al.. Radit. Meas. 34 (2001) 457-461

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Dosemeter response

Calibration with ISO neutron sources and realistic fields at IRSN Cadarache (France)

SourceType of

field

Mean

EnergyRΦ

(neutron-1)

RHp(10)

(cm-2·mSv-1)

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 ± 24252Cf + D2O ISO 539 keV (5.17 ± 0.23)×10-5 518 ± 23

SIGMA Realistic 79 keV (1.422 ± 0.064)×10-5 575 ± 26

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Dosemeter fluence response

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Dosemeter Hp(10.0º) response

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Measurements at EC-IRMM Van der Graaf facility

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 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

Neutron beams and methods

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Measurements at EC-IRMM Van der Graaf facility

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Results

4 dosemeters per energy Background determined with 4 extra non-irradiated dosemeters

Nominal

EnergyTarget

Mean Energy

with BSSRΦ

(neutron-1)

RHp(10)

(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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Results – Dose response

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Conclusions

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!