Cosmic ray produced Radioisotopes for studying the General Circulation in the atmosphere

The possibility of using cosmic ray produced radioisotopes for studying large scale circulation in the atmosphere has been explored recently. The potential significance of these isotopes in the field of metrology arises because of the following features in their production and properties-(l) Several radioisotopes are available whose half-lives are comparable to time scales involved in the atmospheric circulation. Four of the isotopes (S35, Be7, P33, and P32) have half-life periods ranging from three months to a fortnight, and one (Na22) has a half-life of about two and a half years, and (2) Isotope production is continuous, constant, strongly dependent on the latitude and altitude in the atmosphere and independent of meteorological factors, These isotopes can be used for investigating the nature of circulation of air in the troposphere and the detailed mechanism of exchange of air between the stratosphere and the troposphere. Experimental work on the use of these isotopes in meteorology has so far been confined mainly to determination of the concentration in rainwater by the Geophysics Research Group of the Tata Institute of Fundamental Research, Bombay. Some of the important results of these investigations are summarized in this pa per.

Racetrack Microtron—Pushing the Limits

We consider three types of electron accelerators that can be used for various applications, such as industrial, medical, cargo inspection, and isotope production applications, and that require small- and medium-sized machines, namely classical microtron (CM), race-track microtron (RTM), and multisection linac. We review the principles of their operation, the specific features of the beam dynamics in these machines, discuss their advantages and weak points, and compare their technical characteristics. In particular, we emphasize the intrinsic symmetry of the stability region of microtrons. We argue that RTMs can be a preferable choice for medium energies (up to 100 MeV) and that the range of their potential applications can be widened, provided that the beam current losses are significantly reduced. In the article, we analyze two possible solutions in detail, namely increasing the longitudinal acceptance of an RTM using a higher-order harmonic accelerating structure and improving beam matching at the injection.

A prototype compact accelerator-based neutron source (CANS) for Canada

Canada’s access to neutron beams for neutron scattering was significantly curtailed in 2018 with the closure of the National Research Universal (NRU) reactor in Chalk River, Ontario, Canada. New sources are needed for the long-term; otherwise, access will only become harder as the global supply shrinks. Compact Accelerator-based Neutron Sources (CANS) offer the possibility of an intense source of neutrons with a capital cost significantly lower than spallation sources. In this paper, we propose a CANS for Canada. The proposal is staged with the first stage offering a medium neutron flux, linear accelerator-based approach for neutron scattering that is also coupled with a boron neutron capture therapy (BNCT) station and a positron emission tomography (PET) isotope production station. The first stage will serve as a prototype for a second stage: a higher brightness, higher cost facility that could be viewed as a national centre for neutron applications.

Production of Cyclotron-Based Gallium-68 With Low Energy Protons: Preliminary Target Design and Cyclotron Shielding Considerations

Nuclear reactors, cyclotrons and generators are being used to produce nuclear medicine radionuclides. Radiopharmaceuticals based on Gallium-68 are widely used both experimentally and clinically in Positron Emission Tomography (PET). Currently Ga-68 is mainly produced via 68Ge/68Ga generators, which are expensive. An alternative method is by cyclotron using high enriched Zinc-68 via the 68Zn(p,n)68Ga reaction. Investigations have been conducted for producing Ga-68 using a solid target impacted with a proton beam in energies between (13–14) MeV or higher. The main interest of this work is to produce Ga-68 using energies within a lower range, therefore Ga-68 can be accessed to locations with cyclotrons of lower energy. In this article, an approach to a novel target design to get Ga-68 with low energy protons is conducted. Adequate shielding to avoid extra doses outer the cyclotron is also considered. Monte Carlo code FLUKA is used to simulate the processes of interaction of radiation with matter and the radioactive isotope production. For a beam energy of 11 MeV and current on target of 40 μA the simulated produced activity is about 69.1 GBq. The results show the feasibility of producing Ga-68 with low energy protons and self-shielding system guarantees the regulation-based dose exposition outer the cyclotron.

ESTIMATION OF GROSS-STRUCTURE PARAMETERS OF GIANT DIPOLE RESONANCE: 1. A METHOD

Available data on photonuclear cross-sections, both measured experimentally and obtained on the basis of theoretical models, are characterized sometimes by a considerable spread. In work, a simple method for the estimation of width (FWHM) and maximum (σmax) of excitation function of a reaction with dominant giant dipole resonance, is given. An analytical model is developed for the description of isotope production in an X-ray beam. It is shown, that the established yield of the reaction in a thin target, overlapping completely the beam with known end-point photon energy makes it possible to estimate the σmax and FWHM values. The possibilities of new approach are demonstrated by a numerical experiment on the reference reactions.