Neutron Beams

 

 

High-Power Broad-Spectrum Neutron Generator

 

Integral flux up to 1011 /cm2/s of well calibrated broad-spectrum neutrons with mean energy of 14 MeV and extension up to 32 MeV is produced by 37 MeV proton beam interacting with heavy-water (flow) target. The neutron spectral flux across irradiated samples at variable distances (3 to 200 mm) from the target is experimentally determined with an accuracy of 10% backed by the MCNPX simulation.

The design and operation of the high-power fast neutron source NG2 at the negative-ion beam line H was aimed to the integral benchmark tests of neutron cross-sections – in particular for the validation of neutron data library for the fusion technologies (IFMIF – International Fusion Material Irradiation Facility within the F4E program of EU). Besides, the irradiation of small-dimension samples (≤ 15 mm in diameter) is routinely provided for neutron hardness test experiments of HEC/CERN read-out electronics, etc.

 

Quasi-monoenergetic Neutron Generator

 

The standard 7Li(p,n) reaction on thin lithium target (with carbon beam stopper) induced by 20–37 MeV proton beam is used for the production of quasi-monoenergetic neutron field. The neutron flux up to 3 108 n/cm2/s is determined for the 37 MeV/5 μA proton beam and for the target-to-sample distance of 50 mm. The spectral flux at sample position is determined with an accuracy of 10% by the MCNPX calculations validated against experimental data.

The source NG2 was build up on the negative-ion beam line H of the cyclotron to supply the integral benchmark of fusion-technology relevant cross-section data by differential cross-section measurements and to provide the tests/calibrations of various neutron detector systems – in particular, the investigation of fast-neutron response functions of a single-crystal diamond detector, etc

 

Variable-Energy Broad-Spectrum Neutron Generator

 

In the negative-ion mode of acceleration (beam line H), the variable-energy cyclotron U-120M provides beams of protons (6–37 MeV) and deuterons (11–20 MeV), suitable to produce a broad-spectrum neutron fields with variable mean energy in the range from 4 to 12 MeV using standard p/d+Be(thick target) source reactions. Employing reference neutron field data from PTB Braunschweig, reliable spectral flux up to 1011 n/sr/s is provided and utilized for irradiation of large-scale systems (reactor core modules within ADTT database program, etc).

Using the 3He(40 MeV)+D2O neutron source target station on the H beam line incorporated with neutron collimator arrangement, for the different configurations of sample arrangement the set of neutron transmission experiments has been performed, in particular on iron, the main constituent of the IFMIF high-flux test module.