On the fission interference correction and its dependence on the epithermal to thermal neutron flux ratio in thermal naa of molybdenum

1999 ◽  
Vol 71-72 (1) ◽  
pp. 471-479 ◽  
Author(s):  
E. Martinho ◽  
M. C. Freitas
Keyword(s):  
Neutron Flux ◽  
Thermal Neutron ◽  
Thermal Neutron Flux ◽  
Flux Ratio ◽  
Interference Correction ◽  
Neutron Flux Ratio

scholarly journals Design of an irradiation rig using screen method for silicon transmutation doping at the Dalat research reactor

2019 ◽  
Vol 9 (1) ◽  
pp. 1-8
Author(s):  
Huy Pham Quang ◽  
Dien Nguyen Nhi ◽  
Cuong Nguyen Kien ◽  
Duong Tran Quoc ◽  
Dang Vo Doan Hai ◽  
...  
Keyword(s):  
Neutron Flux ◽  
Thermal Neutron ◽  
Thermal Neutron Flux ◽  
Research Reactor ◽  
Flux Ratio ◽  
Nuclear Research ◽  
Research Centre ◽  
Screen Method ◽  
Transmutation Doping ◽  
Design And Testing

The neutron transmutation doping of silicon (NTD-Si) at research reactors has beensuccessfully implemented in many countries to produce high-quality semiconductors. In the late 1980s, NTD-Si has been tested at the Dalat Nuclear Research Reactor (DNRR) but the results have been limited. Therefore, the design and testing of an irradiation rig for NTD-Si at the DNRR are necessary to have a better understanding in order to apply the NTD-Si in a new research reactor of the Research Centre for Nuclear Science and Technology (RCNEST), which has planned to be built in Viet Nam. This paper presents the design and testing of a new irradiation rig using screen method for testing NTD-Si at the DNRR. The important parameters in the rig such as neutron spectrum and thermal neutron flux distribution were determined by both calculation using MCNP5 computer code and experiment. The aluminum ingots, which have similar neutronic characteristics with silicon ingots, were irradiated in the rig to verify the appropriate design. The uniformity of thermal neutron flux in the rig is less than 5% in axial and 2% in radial directions, respectively. However, the thermal/fast flux ratio of the irradiation rig is 4.38/1 would affect target resistivity of testing Silicon ingots after irradiation.

scholarly journals Practical, visible wavelength nuclear-pumped laser

1993 ◽  
Vol 11 (3) ◽  
pp. 559-566 ◽  
Author(s):  
Y.R. Shaban ◽  
G.H. Miley
Keyword(s):  
Neutron Flux ◽  
Thermal Neutron ◽  
Thermal Neutron Flux ◽  
Visible Region ◽  
Laser Cavity ◽  
Pumping Power ◽  
University Of Illinois ◽  
Triga Reactor ◽  
Visible Wavelength ◽  
The University

A practical, visible nuclear-pumped laser (NPL) has been sought at the University of Illinois and other laboratories for a number of years. Yet, the results from successful visible NPLs to date have not been fully satisfactory, e.g., the threshold pumping power is too high for conventional applications. Progress in recent studies of 3He-Ne-H2 as a candidate NPL operating in the visible region at 585.3 nm on the 2P1,-1S2 Ne transition is described. We obtained lasing on the above transition for 3He-Ne-H2 concentrations of 1,140, 588, and 412 torr, respectively, with the laser cavity placed in the beamport of the University of Illinois TRIGA reactor. The threshold thermal neutron flux is 1014 n/cm2-s, corresponding to a threshold pumping power of 5 W/cm3.

Thermal neutron flux characterization at aircraft altitudes with the TinMan detector

2017 ◽  
Author(s):  
Suzanne Nowicki ◽  
Stephen Wender ◽  
Aaron Couture ◽  
Laura Dominik ◽  
Adam Warniment ◽  
...  
Keyword(s):  
Neutron Flux ◽  
Thermal Neutron ◽  
Thermal Neutron Flux ◽  
Neutron Flux Characterization

Determination of thermal neutron flux distribution at the rotary rack served for elemental concentration analysis using the k0-INAA method

2021 ◽  
Vol 10 (1) ◽  
pp. 11-20
Author(s):  
Tho Nguyen Thi ◽  
Anh Tran Tuan ◽  
Cuong Trinh Van ◽  
Doanh Ho Van ◽  
Duong Tran Quoc ◽  
...  
Keyword(s):  
Neutron Flux ◽  
Thermal Neutron ◽  
Flux Distribution ◽  
Thermal Neutron Flux ◽  
Epithermal Neutron ◽  
Epithermal Neutron Flux ◽  
Irradiation Position ◽  
Neutron Flux Distribution ◽  
Sample Irradiation

The accuracy of elements concentration determination using the k0-standardization method directly depends on irradiation and measurement parameters including Non-1/E epithermal neutron flux distribution shape α (ϕ epi ≈1/E1+α ) , thermal-to-epithermal neutron flux ratio f, efficiency ε, peak area… In the case of the irradiation position at the rotary rack of the Dalat Nuclear Research Reactor (DNRR), the difference of thermal neutron flux between the bottom (3.54x1012 n.cm-2.s-1) and the top (1.93x1012 n.cm-2.s-1) of the 15 cm aluminum container is up to 45%. Therefore, it is necessary to accurately determine above-mentioned parameters in the sample irradiation position. The present paper deals with the determination of the distribution of thermal neutron flux along the sample irradiation container by using 0.1% Au–Al wire activation technique. The thermal neutron flux was then used to calculate the concentration of elements in the Standard Reference Material 2711a and SMELS type III using k0-INAA method at different positions in the container. The obtained results with the neutron flux correction were found to be in good agreement with the certified values. In conclusion, the proposed technique can be applied for activation analyses without sandwiching flux monitors between samples during irradiations.

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