Studies of Helium proportional Studies of Helium proportional counters response on fast neutrons, counters response on fast neutrons,

at NCSR “Demokritos”at NCSR “Demokritos”

M. Zamani, M. Zamani, M. ManolopoulouM. Manolopoulou,,

S. Stoulos, M. Fragopoulou S. Stoulos, M. Fragopoulou

School of Physics, Faculty of SciencesAristotle University of Thessaloniki

Thessaloniki, Hellas

ARISTOTLE UNIVERSITY OF THESSALONIKIARISTOTLE UNIVERSITY OF THESSALONIKI

ObjectivesObjectives

Optimization of operation parameters of the Optimization of operation parameters of the counterscounters

Determination of counter responseDetermination of counter response Application: Measurement and analysis of Application: Measurement and analysis of

neutron spectra emitted from the spallation neutron spectra emitted from the spallation source “Energy plus Transmutation"source “Energy plus Transmutation"

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Helium counters characteristicsHelium counters characteristics

PressuPressure re

[Atm][Atm]

GasGas

mixturemixture

LengtLengthh

[cm][cm]

DiametDiameter [cm]er [cm]

He-3He-3 66

33He 65%He 65%

Kr 33%Kr 33%

COCO2 2 2% 2%1515 55

He-4He-4 181844He 99%He 99%

COCO2 2 1% 1%6060 55

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Irradiations at the Institute of Irradiations at the Institute of Nuclear Physics, NCSR Demokritos Nuclear Physics, NCSR Demokritos

Proton Beam:Proton Beam: 2.0 – 5.0 MeV 2.0 – 5.0 MeV77Li(p,n)Li(p,n)77Be neutron energy: 0.23 – 3.3 MeVBe neutron energy: 0.23 – 3.3 MeV

Deuteron Beam:Deuteron Beam: 1.4 – 7.8 MeV 1.4 – 7.8 MeV22H(d,n)H(d,n)33He neutron energy: 3.7 – 10.7 MeVHe neutron energy: 3.7 – 10.7 MeV33H(d,n)H(d,n)44He neutron energy: 17.5 – 20.5 MeVHe neutron energy: 17.5 – 20.5 MeV

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He-3 counter spectraHe-3 counter spectra

Full energy Full energy peakpeak

33He(n,p)He(n,p)33HH

Recoil peak Recoil peak 33He(n,elastic)He(n,elastic)

33He(n,d)He(n,d)22HH

Thermal – epithermal peak (764 keV)Thermal – epithermal peak (764 keV)

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He-4 counter spectraHe-4 counter spectra

44He(n,elastic)He(n,elastic)

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Operational characteristics of He-3 Operational characteristics of He-3 and He-4 countersand He-4 counters

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““Energy plus Transmutation” Energy plus Transmutation” setupsetup

Pb target: Diameter 8.4 cm, Length 48 cm Natural Uranium ≈206 kg NUCLOTRON accelerator, Laboratory NUCLOTRON accelerator, Laboratory of High Energies, Dubna - JINRof High Energies, Dubna - JINR

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Neutron energy distributionNeutron energy distributioncalculated by DCM-DEM codecalculated by DCM-DEM code

Proton beam: 1 GeVProton beam: 1 GeV

ARISTOTLE UNIVERSITY OF THESSALONIKIARISTOTLE UNIVERSITY OF THESSALONIKI

Irradiation of “Energy plus Irradiation of “Energy plus Transmutation” setup with Transmutation” setup with

Deuterons 1.6 GeVDeuterons 1.6 GeV

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Neutron energy distributionNeutron energy distribution(preliminary results)(preliminary results)

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Future plansFuture plans

Calibration of neutron dosimeter Calibration of neutron dosimeter systems based on SSNT detectors.systems based on SSNT detectors.

Study of proton track geometrical Study of proton track geometrical parameters on SSNT detectors for parameters on SSNT detectors for application in neutron spectroscopy.application in neutron spectroscopy.

Fast neutron dosimetry with MOSFET.Fast neutron dosimetry with MOSFET. Cross section of (Cross section of (α,α,n) and (p,n) n) and (p,n)

reactions in the energy region of reactions in the energy region of several MeV.several MeV.