Gas-discharge plasma application for ion-beam treatment of the holes’ inner surfaces

The possibility to modify the holes and pipes’ inner surface with focused high-intensity low-energy ion beams was first shown in this work. The studies were carried out using an axially symmetric single-grid system for the ions’ extraction from a free plasma boundary with subsequent ballistic focusing of the ion beam. Ion implantation of the inner surface was carried out in the region of the ion beam defocusing. The studies considered the effect of a nitrogen ions’ beam with energy of 1.4 keV on the inner surface of a tube with a diameter of 20 mm made of stainless steel AISI 321. The beams were formed with a repetition rate of 40 kHz and pulse durations of 5, 7.5 and 10 μs. It is shown that the mutual deposition of the sputtered material on the tube’ opposite sides partly compensates for ion sputtering. As a result of implantation of the inner surface of a pipe made of stainless steel AISI 321, the nitride layers with a thickness of more than 15 microns with a nitrogen dopant content of 22-30 at.% were obtained.

The Performance of LiF:Mg-Ti for Proton Dosimetry within the Framework of the MoVe IT Project

Proton therapy represents a technologically advanced method for delivery of radiation treatments to tumors. The determination of the biological effectiveness is one of the objectives of the MoVe IT (Modeling and Verification for Ion Beam Treatment Planning) project of the National Institute for Nuclear Physics (INFN) CSN5. The aim of the present work, which is part of the project, was to evaluate the performance of the thermoluminescent dosimeters (TLDs-100) for dose verification in the proton beam line. Four irradiation experiments were performed in the experimental room at the Trento Proton Therapy Center, where a 150 MeV monoenergetic proton beam is available. A total of 80 TLDs were used. The TLDs were arranged in one or two rows and accommodated in a specially designed water-equivalent phantom. In the experimental setup, the beam enters orthogonally to the dosimeters and is distributed along the proton beam profile, while the irradiation delivers doses of 0.8 Gy or 1.5 Gy in the Bragg peak. For each irradiation stage, the depth–dose curve was determined by the TLD readings. The results showed the good performance of the TLDs-100, proving their reliability for dose recordings in future radiobiological experiments planned within the MoVe IT context.

Changes in structural-phase state and physicochemical properties of tungsten-free TIC-TiNi hard alloys after various types of ion-beam treatment

Using experimental methods of analysis, the morphology, elemental composition and chemical state of hard alloys of the «TiC-TiNi» system in the initial state and after various types of ion-beam treatment have been investigated. It is found that the effect of a continuous ion beam leads to an increase in the microhardness of the investigated alloys by 10–12 %. When samples are irradiated with a pulsed ion beam, as a result of destruction of surface layers, the microhardness value decreases by 20 %, as a result of which this type of modification is not preferable for alloys of the TiC-TiNi system

ALLOYING THE SURFACE OF STEEL 30KHGSN2A TO INCREASE ITS TRIBOLOGICAL CHARACTERISTICS

The results of evaluating the wear of samples of the model of the same name pair of friction from alloy steel 30KhGSN2A after ion beam treatment and dry friction under conditions of heavy contact are presented. It was shown that in the steady state friction, the wear resistance of steel as a result of implantation of copper ions at an irradiation dose of 1017 ion / cm2 and 5.1017 ion / cm2 increases by 2 and 1.5 times, respectively. The mechanism of the «long-range effect» in ion-doped structural materials under conditions of contact deformation is discussed.