Search results for "plasma physics"
showing 10 items of 393 documents
Measurement of radon-induced backgrounds in the NEXT double beta decay experiment
2018
The measurement of the internal $^{222}$Rn activity in the NEXT-White detector during the so-called Run-II period with $^{136}$Xe-depleted xenon is discussed in detail, together with its implications for double beta decay searches in NEXT. The activity is measured through the alpha production rate induced in the fiducial volume by $^{222}$Rn and its alpha-emitting progeny. The specific activity is measured to be $(38.1\pm 2.2~\mathrm{(stat.)}\pm 5.9~\mathrm{(syst.)})$~mBq/m$^3$. Radon-induced electrons have also been characterized from the decay of the $^{214}$Bi daughter ions plating out on the cathode of the time projection chamber. From our studies, we conclude that radon-induced backgro…
Energy calibration of the NEXT-White detector with 1% resolution near Q ββ of 136Xe
2019
Excellent energy resolution is one of the primary advantages of electroluminescent high pressure xenon TPCs, and searches for rare physics events such as neutrinoless double-beta decay ($\beta\beta0\nu$) require precise energy measurements. Using the NEXT-White detector, developed by the NEXT (Neutrino Experiment with a Xenon TPC) collaboration, we show for the first time that an energy resolution of 1% FWHM can be achieved at 2.6 MeV, establishing the present technology as the one with the best energy resolution of all xenon detectors for $\beta\beta0\nu$ searches.
Fourier transform-ion cyclotron resonance mass spectrometry — A new tool for measuring highly charged ions in an electron beam ion trap
1995
Abstract Fourier transform-ion cyclotron mass spectrometry has been applied to the study of highly charged ions produced and confined in an electron beam ion trap. Measurements of the relative ion abundance of hydrogenlike and bare krypton ions were made and compared to the abundance ratios determined with standard X-ray techniques. Good agreement was found establishing the reliability of the method as a new tool in highly charged ion research.
Recent progress in L-H transition studies at JET: tritium, helium, hydrogen and deuterium
2022
Abstract We present an overview of results from a series of L–H transition experiments undertaken at JET since the installation of the ITER-like-wall (JET-ILW), with beryllium wall tiles and a tungsten divertor. Tritium, helium and deuterium plasmas have been investigated. Initial results in tritium show ohmic L–H transitions at low density and the power threshold for the L–H transition (P LH) is lower in tritium plasmas than in deuterium ones at low densities, while we still lack contrasted data to provide a scaling at high densities. In helium plasmas there is a notable shift of the density at which the power threshold is minimum ( n ¯ e , min ) to higher values relative to deuterium and …
Applicability of the dielectric barrier discharge for helium ash measurements in the divertor region
2016
Abstract Controlled fusion based on the magnetic confinement of the plasma is one of the main aims of the Euro-fusion programme. In the fusion device, the hydrogen isotopes, in nuclear reactions, will produce helium nuclei. The products, as the ash, will be removed from the plasma in the region of the so-called divertor. Controlling the helium to hydrogen ratio in this ‘exhaust gas’ will provide information about the efficiency of the fusion process as well as of the efficiency of the helium removal system. One of the methods to perform this task is to study the properties of the discharge conducted in such exhaust gas. In this paper, the applicability of the dielectric barrier discharge (D…
Production and release of ISOL beams from molten fluoride salt targets
2014
In the framework of the Beta Beams project, a molten fluoride target has been proposed for the production of the required 1013 18Ne/s. The production and extraction of such rates are predicted to be possible on a circulating molten salt with 160 MeV proton beams at close to 1 MW power. As a most important step to validate the concept, a prototype has been designed and investigated at CERN-ISOLDE using a static target unit. The target material consisted of a binary fluoride system, NaF:LiF (39:61 mol.%), with melting point at 649 °C. The production of Ne beams has been monitored as a function of the target temperature and proton beam intensity. The prototype development and the results of th…
Cooling of the plasma chamber for the AECR-U type electron cyclotron resonance ion source ARTEMIS
2001
Abstract The temperature distribution inside the ECRIS plasma chamber has been studied using finite element analysis. The main goal of these studies was to find out the safest cooling design for the temperature sensitive permanent magnets. In ECR ion sources they are used to provide the hexapole field. Two different designs for the cooling of the magnets were investigated. The temperature distribution on the surface of the plasma electrode was also studied. With the aid of the cooling simulations the most efficient cooling for the new ECR ion source was found. As a result of which, safety and higher reliability of operation can be reached.
Simulation studies of the laser ablation ion source at the SHIPTRAP setup
2020
Hyperfine interactions 241(1), 46 (2020). doi:10.1007/s10751-020-01708-0
High-resolution spectroscopy of gaseous $^\mathrm{83m}$Kr conversion electrons with the KATRIN experiment
2020
In this work, we present the first spectroscopic measurements of conversion electrons originating from the decay of metastable gaseous $^\mathrm{83m}$Kr with the Karlsruhe Tritium Neutrino (KATRIN) experiment. The results obtained in this calibration measurement represent a major commissioning milestone for the upcoming direct neutrino mass measurement with KATRIN. The successful campaign demonstrates the functionalities of the full KATRIN beamline. The KATRIN main spectrometer's excellent energy resolution of ~ 1 eV made it possible to determine the narrow K-32 and L$_3$-32 conversion electron line widths with an unprecedented precision of ~ 1 %.
Molecular dynamics simulation of the damage production in Al (110) surface with slow argon ions
1986
We have developed a molecular dynamics simulation program to gain more insight into the sputtering process, especially the damage produced by it. We have studied the sputtering of aluminium (110) surface with argon ions. The Morse pair potentail was used for Al−Al interaction, the Lennard-Jones potential for Ar−Ar interaction and both the Moliere potential and the universal potential of Ziegler et al. for Ar−Al interaction. An electronic friction term proportional to the particle velocities was also used. The studied incident argon ion energies and angles were 200 and 400 eV and 0° (normal), 25°, 45° and 75°, respectively. The calculated sputtering yield and the overall shape and the mean d…