Magnetic Selector Research Articles

A Platform for Ultra-Fast Proton Probing of Matter in Extreme Conditions.

Recent developments in ultrashort and intense laser systems have enabled the generation of short and brilliant proton sources, which are valuable for studying plasmas under extreme conditions in high-energy-density physics. However, developing sensors for the energy selection, focusing, transport, and detection of these sources remains challenging. This work presents a novel and simple design for an isochronous magnetic selector capable of angular and energy selection of proton sources, significantly reducing temporal spread compared to the current state of the art. The isochronous selector separates the beam based on ion energy, making it a potential component in new energy spectrum sensors for ions. Analytical estimations and Monte Carlo simulations validate the proposed configuration. Due to its low temporal spread, this selector is also useful for studying extreme states of matter, such as proton stopping power in warm dense matter, where short plasma stagnation time (<100 ps) is a critical factor. The proposed selector can also be employed at higher proton energies, achieving final time spreads of a few picoseconds. This has important implications for sensing technologies in the study of coherent energy deposition in biology and medical physics.

Production, characterization and scattering of a sulfur atom beam: Interatomic potentials for the rare-gas sulfides, RS (R = Ne, Ar, Kr, Xe)

An intense and stable continuous beam of S atoms and SO radicals is produced from a microwave discharge source operating in a SO2–He mixture. The S-atom beam, characterized by coupling mechanical velocity selection with magnetic analysis and detected by a quadrupole mass filter, has been employed in scattering experiments. The transmittance across a Stern–Gerlach magnetic selector, measured mass-spectrometrically at m/z=32 and 34 as a function of the beam velocity and of the deflecting field strength, indicates that the sulfur atoms are mainly in their electronic ground state 3Pj, with fine structure levels j=0, 1, 2 populated according to their degeneracies. Total integral cross-sections for collisions of S (3Pj) atoms with Ne, Ar, Kr and Xe have been measured in the beam velocity range 1.0–2.4 km s−1. The scattering data exhibit a glory interference effect with quenching of the amplitude of the glory pattern which increases along the rare-gas series from Ne to Xe. The results are analysed to yield a characterization of the spherical and anisotropic components of the interaction, providing lengths and strengths of the bonds in the six low lying states of the rare-gas sulfides NeS, ArS, KrS and XeS.

Decay of 129Ce to low-lying positive-parity states in 129La

Low-lying levels of the 129La isotope have been investigated through the β+/EC decay of 129Ce. The radioactive nuclei were produced in the 94Mo+40Ca reaction at a bombarding energy of 255 MeV and transported with a He-jet system. On-line mass separation was used to select the 129Ce beta-decay γ-γ-t, X- γ- t, e−-γ -t coincidence measurements as well as time multi-analysis were performed. Internal conversion electrons were recorded with a magnetic selector and multipolarities deduced. The level scheme of 129La is discussed and compared with the calculations made in the frame of the neutron-proton Interacting Boson-Fermion Model (IBFM-2).

Non-yrast level structures in the isotopes 131Pr and 131La

Low-lying levels of 131Pr and 131La isotopes have been investigated by means of β/EC decays of 131Nd and 131Ce, respectively. The radioactive nuclei were produced in the 94Mo+ 40Ca reaction at a bombarding energy of 255 MeV and transported with a He-jet system. The identification and the characteristics of the 131mPr isomer (5.7 s) were obtained by applying both He-jet techniques and on-line gamma-ray spectroscopy with mechanically pulsed beams. γγt, X γt, e − γt coincidence measurements as well as time multi-analysis were performed. Internal conversion electrons were recorded with a magnetic selector and multipolarities deduced. Level schemes of 131Pr and 131La are discussed and compared to those of neighboring odd-Z Pr and La isotopes using calculations made in the frame of the Interacting Boson-Fermion Model.

Process for Pan Coating Small Batches of Tablets

A method is presented which permits the pan coating of small lots of tablets with production-size characteristics. This is readily accomplished by coating the tablets containing the active ingredient simultaneously with placebo tablets of the same dimensions. The procedure involves incorporating a small amount of reduced iron in the placebo, combining both the active and placebo tablets, coating the mixed batch of tablets and finally separating the active from placebo tablets by passing them through a magnetic selector.

Modification of strontium 90 emission for superficial therapy.

The heteroenergetic emission of β particles from radioactive materials may be modified for the more favourable treatment of superficial disease. In this study the β particles emitted by a strontium 90 source within an angle of 80 deg. were screened and redirected by a magnetic selector. The output consisted of a broad field of electrons moving in about the same direction and with a selected range of energies controllable by the magnetic field. The distribution of ionization in depth of tissue produced by the highest energy band, 1·4 to 2·1 MeV, was similar to that produced by monoenergetic 1·6 MeV electrons.