The flux weighted cross sections of 179Hf(γ,γ')179mHf and natHf(γ,x)179mHf reactions at 8 MeV and 15 MeV bremsstrahlung end point energies.

For the hafnium element, the cross sections of 179Hf(γ,γ')179mHf and natHf(γ,x)179mHf reactions were measured at 8 MeV and 15 MeV bremsstrahlung end point energies respectively using activation method and off-line gamma-ray spectroscopy. The bremsstrahlung radiation spectra were generated by bombarding a 0.1 mm tungsten target with 8 MeV and 15 MeV electrons at 5 µA beam current and also theoretically simulated by GEANT4 computer code. The flux weighted average cross sections of 179Hf (γ,γ')179mHf and natHf(γ,x)179mHf reactions were measured by using 115In(γ,γ')115mIn and 197Au(γ,n)196Au as flux monitor reactions at 8 MeV and 15 MeV bremsstrahlung radiation respectively. The measured cross sections are found close to the corresponding theoretical cross sections estimated by TALYS 1.95 and TENDL 2019 computer codes. These hafnium cross sections at 8 MeV and 15 MeV bremsstrahlung radiation will be new additions to the EXFOR library, as so far not reported in literature.

Monte Carlo based investigations of electron contamination from telecobalt unit head in build up region and its impact on surface dose.

A Telecobalt unit has wide range of applications in cancer treatments and is used widely in many countries all around the world. Estimation of surface dose in Cobalt-60 teletherapy machine becomes important since clinically useful photon beam consist of contaminated electrons during the patient treatment. EGSnrc along with the BEAMnrc user code was used to model the Theratron 780E telecobalt unit. Central axis depth dose profiles including surface doses have been estimated for the field sizes of 0×0, 6×6, 10×10, 15×15, 20×20, 25×25, 30×30cm2 and at Source-to-surface distance (SSD) of 60 and 80cm. Surface dose was measured experimentally by the Gafchromic RTQA2 films and are in good agreement with the simulation results. The central axis depth dose data are compared with the data available from the British Journal of Radiology report no. 25. Contribution of contaminated electrons has also been calculated using Monte Carlo simulation by the different parts of the Cobalt-60 head for different field size and SSD's. Moreover, depth dose curve in zero area field size is calculated by extrapolation method and compared with the already published data. They are found in good agreement.

Design of 6Mev linear accelerator based pulsed thermal neutron source: FLUKA simulation and experiment.

The 6MeV LINAC based pulsed thermal neutron source has been designed for bulk materials analysis. The design was optimized by varying different parameters of the target and materials for each region using FLUKA code. The optimized design of thermal neutron source gives flux of 3×10(6)ncm(-2)s(-1) with more than 80% of thermal neutrons and neutron to gamma ratio was 1×10(4)ncm(-2)mR(-1). The results of prototype experiment and simulation are found to be in good agreement with each other.

Measurement of angular distribution of neutron flux for the 6MeV race-track microtron based pulsed neutron source.

The 6MeV race track microtron based pulsed neutron source has been designed specifically for the elemental analysis of short lived activation products, where the low neutron flux requirement is desirable. Electrons impinges on a e-gamma target to generate bremsstrahlung radiations, which further produces neutrons by photonuclear reaction in gamma-n target. The optimisation of these targets along with their spectra were estimated using FLUKA code. The measurement of neutron flux was carried out by activation of vanadium at different scattering angles. Angular distribution of neutron flux indicates that the flux decreases with increase in the angle and are in good agreement with the FLUKA simulation.