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The process of ionization that is due to the Migdal effect and which occurs in the elastic scattering of a heavy neutral particle, including a weakly interacting massive particle (WIMP), on a noble-gas atom in the case of its small recoil energy is considered. The mean number of primary and secondary electrons emitted in an individual event of such ionization is estimated, and the energy distributions of primary electrons are obtained. The calculations were performed for various noble-gas atoms with allowance for experimental data on their ionization by photons. [ABSTRACT FROM AUTHOR]

A method for improving the production of the radioisotope 123I in proton cyclotrons, which makes it possible to increase its technological yield by 2–3 times, is reported. For this purpose, it is proposed to introduce hydrogen into a target with 124Xe, which makes it possible to extract from it the 123I formed over the irradiation time on decay of the accumulated 123Xe. [ABSTRACT FROM AUTHOR]

Free-electron emission by stopping recoil atoms arising from particle–atom collisions in a noble-gas medium is numerically investigated using argon as an example. We demonstrate that, during propagation through matter of recoil atoms with energies over a few keV, vacancies in their internal L-shells arise via the Pauli mechanism with a probability on the order of 100%. As a result, over 30 free electrons are released upon a single interaction act in liquid or gaseous noble gas as a working medium of a particle detector. Thereby, the sensitivity of an argon-filled particle detector is significantly enhanced. In a xenon-filled detector, Pauli ionization sets in at higher recoil-atom energies of ≳100−200 keV and, therefore, is unlikely to boost the detector sensitivity to light-dark-matter particles, which are generally expected to produce recoil atoms with energies ≲10 keV. [ABSTRACT FROM AUTHOR]