1 Neutron Filtered Beam Technique At Kyiv Research Reactor For Scientific And Technological Purposes STCU Workshop "From Science to Business" 11 – 12 October 2006, Kyiv Olena Gritzay Institute for Nuclear Research NAS Ukraine Kyiv

2 Key concept The general idea of neutron filter technique is the transmission of reactor neutron spectrum through the thick layers of materials (up to 2 m), which nuclei have the deep interference minimums in total cross section of neutron interaction with nuclei Through these minimums the neutrons transmit and form rather narrow (in energy) quasi-monochromatic filtered beams

3 The typical view of neutron filter at reactor horizontal experimental channel. 1 – reactor core, 2 – beryllium reflector;3 – horizontal channel tube; 4 – beam shutter disks; 5 – preliminary collimator; 6 – filter-assembles; 7 – filter components; 8 – outside collimator n/cm 2 s 10 5 n/cm 2 s n/cm 2 s10 8 n/cm 2 s

4 Opportunities: The main tasks for scientific research High precision measurements ( %) of total and partial cross sections Precise measurements (to 1 %) of neutron cross sections, the getting of averaged nuclear parameters Measurements of neutron capture gamma-spectra Measurements of inel for the first exited levels of heavy nuclides Measurements of activation cross sections

5 Opportunities: The main tasks for applied investigations Prompt Gamma-ray Activation Analysis (PGAA) Development of standard fluxes for reactor-dosimetry purposes Energy calibration of proton recoil counters Neutron radiography and tomography Bio-medical investigations Neutron and Boron-neutron capture therapy

6 Neutron filters used at the KRR for fundamental investigations

7 The set of natural elements and high-pure isotopes that were used for neutron filters development: Natural elements: Si, Al, V, Sc, S, Mn, Fe, B, Ti, Mg, Co, Ce, Rh, Cd, LiF. High-pure isotopes: 52 Сr (99.3), 54 Fe (99.92), 56 Fe (99.5), 57 Fe (99.1), 58 Ni (99.3), 60 Ni (92.8 – 99.8), 62 Ni (98.04), 80 Se (99.2), 10 B (85), 7 Li (90).

8 Photograph of filter

9 Neutron filter technique allows to extract from white neutron reactor spectrum a neutron line with certain energy. Merits Neutron line with energies from thermal to several hundred kilo-electron-volts High intensity 10 6 – 10 8 n/cm 2 s Demerits Presence of parasitic energy lines in filtered neutron spectrum High price of high-pure isotopes

10 The main characteristics of this development are in following : Neutron filter technique at KRR has been developed for more than 20 years, the large experience has been accumulated. Filtered beams are very intensive. Flux is in the range neutrons/s*cm 2. There are very few neutron sources in the world with such intensive beams in kilo-electron-volt energy region.

11 Such intensities give the possibilities for very precise and unique measurements. We have at ours disposal rather large quantities of high-pure (stable) isotopes ( 52 Cr, 54,56,57 Fe, 58,60 Ni, etc). For this reason we may form the filters with very high intensities and good quality. The main characteristics … (continuation):

12 Resources &proposal Precise measurements of total, scattering and capture cross sections at KRR using NFBT Assistance in development of neutron filters with main component from natural elements

13 Contact information Olena GRITZAY Tel Institute for Nuclear Research NAS Ukraine Kyiv Technology Reference: Alexander Sich