A reference neutron field for measurement of spectrum averaged cross sections

Košťál, Michal; Schulc, Martin; Losa, Evžen; Šimon, Jan; Burianová, Nicola; Novák, Evžen; Mareček, Martin; Uhlíř, Jan; Czakoj, Tomáš; Rypar, Vojtěch; Juříček, Vlastimil; Capote, R.; Trkov, A.

doi:10.1016/j.anucene.2019.107119

Cited by 23 publications

(9 citation statements)

References 29 publications

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“…[ 1,5 ] Fast neutrons from the reference field of the LR‐0 reactor were used for uniform lifetime reduction. [ 6 ] Diodes were irradiated at room temperature with fluences ranging from 5.6 × 10 10 to 5.9 × 10 12 cm −2 (1 MeV SiC equivalent). The local lifetime reduction was realized by irradiation with 800 keV or 1 MeV protons using the 3 MeV tandetron accelerator.…”

Section: Methodsmentioning

confidence: 99%

Radiation Defects and Carrier Lifetime in 4H‐SiC Bipolar Devices

Hazdra

Smrkovský

Popelka

2021

Physica Status Solidi (a)

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The effect of radiation damage on the minority carrier lifetime in the 4 H‐SiC epilayers forming the n‐base of the power p–i–n diodes is presented. Irradiation with fast neutrons and MeV protons is used for uniform and local lifetime reduction. Deep‐level transient spectroscopy in combination with open‐circuit voltage decay measurement shows that the carrier lifetime is reduced by increased carrier recombination on Z1/Z2, EH3, and possibly RD4 levels. The lifetime degrades swiftly and the ON‐state carrier modulation capability of high‐voltage devices can be easily lost already at very low fluences. The results further show that the proton irradiation provides an excellent tool for local lifetime tailoring. The carrier lifetime can be easily set by proton fluence and localized by proton energy. The proper local lifetime reduction speeds up diode recovery without an undesirable increase in the forward voltage drop. However, attention must be taken to properly locate the damage maximum so as not to increase device leakage.

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Section: Methodsmentioning

confidence: 99%

Radiation Defects and Carrier Lifetime in 4H‐SiC Bipolar Devices

Hazdra

Smrkovský

Popelka

2021

Physica Status Solidi (a)

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“…The effect of inserted graphite is described in detail in the results section. The obtained results of fuel assembly power shaping can be compared with core power distribution in the reference neutron field (Košťál, 2020).…”

Section: Mcnp and Serpent Calculationsmentioning

confidence: 99%

“…The assumption determined by the calculation is a very well thermalised neutron spectrum in the proposed reactor core with graphite insertion, as shown in Figure 9. The total neutron spectrum was calculated using MCNP and Serpent in the centre of the graphite insertion and then compared with the neutron spectrum of the reference core without graphite (Košťál M. et al, 2020) determined in MCNP. Serpent and MCNP calculations are in excellent agreement, and obtained results were normalised to 1 by integrating over the entire neutron spectrum.…”

Section: Fast Neutron Spectrum Evaluationmentioning

confidence: 99%

Characterisation of neutron field in large graphite insertion in special core of the LR-0 reactor

Peltan

Vilimova²,

Czakoj³

et al. 2023

Annals of Nuclear Energy

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“…The LR-0 research reactor is a zero-power light water pool type reactor. The specially designed reference core [5] consists of six uranium fuel assemblies with nearly 3.3% 235 U enrichment surrounding a dry assembly with activation foils to be irradiated. Used fuel assemblies are the same as the VVER-1000 type in the radial direction but in the axial direction, they are shortened to 125 cm.…”

Section: Neutron Sources Descriptionmentioning

confidence: 99%

Spectral averaged cross sections as a probe to a high energy tail of ²³⁵U PFNS

et al. 2023

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The systematic evaluations of spectrum averaged cross sections of dosimetric reactions over a broad range of energies were performed in 252Cf (spontaneous fission) and 235U(nth,f) neutron fields. The neutron sources used in this study were LR-0, VR-1 zero power research light water reactors, LVR-15 10 MW research light water reactor, and 252Cf neutron source with emission specified precisely by the manganese sulphate bath. All spectral averaged cross sections were inferred from measured reaction rates which were derived from gamma spectrometry. These gamma spectrometry measurements were performed using a single detector in all cases. The ratios of 252Cf and 235U spectral averaged cross sections can be used to specify the high energy tail of the 235U prompt fission neutron spectrum as the 252Cf spontaneous fission spectrum is considered as a standard. Furthermore, ratios are independent of cross section uncertainties since uncertainties in the cross sections are eliminated. Theoretical models of fission can be tested based on our measurements. The calculations were performed in MCNP6.2 transport code using different prompt fission neutron spectra and IRDFF-II cross sections for threshold reactions. The ratios are in good agreement using only ENDF/B-VIII.0 235U prompt fission neutron spectrum suggesting it to be harder than in other evaluations.

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A reference neutron field for measurement of spectrum averaged cross sections

Cited by 23 publications

References 29 publications

Radiation Defects and Carrier Lifetime in 4H‐SiC Bipolar Devices

Radiation Defects and Carrier Lifetime in 4H‐SiC Bipolar Devices

Characterisation of neutron field in large graphite insertion in special core of the LR-0 reactor

Spectral averaged cross sections as a probe to a high energy tail of ²³⁵U PFNS

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A reference neutron field for measurement of spectrum averaged cross sections

Cited by 23 publications

References 29 publications

Radiation Defects and Carrier Lifetime in 4H‐SiC Bipolar Devices

Radiation Defects and Carrier Lifetime in 4H‐SiC Bipolar Devices

Characterisation of neutron field in large graphite insertion in special core of the LR-0 reactor

Spectral averaged cross sections as a probe to a high energy tail of 235U PFNS

Contact Info

Product

Resources

About

Spectral averaged cross sections as a probe to a high energy tail of ²³⁵U PFNS