Paper | Title | Page |
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TUACH01 | Status of the High Voltage Electron Cooler Project for NICA Collider | 58 |
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The electron cooling system at electron energy up to 2.5 MeV for the NICA collider is under design at JINR. The magnetic system and system of transfer of capacity on high potential is developed. The high voltage generator prototype on 250 kV was tested. The technical design of the electron cooling system was started. | ||
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Slides TUACH01 [1.035 MB] | |
TUPPB005 | LEPTA Project: Towards Positronium | 316 |
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The project of the Low Energy Positron Toroidal Accumulator (LEPTA) is under development at JINR. The LEPTA facility is a small positron storage ring equipped with the electron coolin system. The project positron energy is of 2 – 10 keV. The main goal of the facility is to generate an intense flux of positronium atoms – the bound state of electron and positron. Storage ring of LEPTA facility was commissioned in September 2004 and was under development up to now. The positron injector has been constructed in 2005 - 2010, and beam transfer channel – in 2011. By the end of August 2011 experiments on electron and positron injection into the ring have been started. The recent results are presented here. | ||
TUPPB006 | Compression and Confinement of Positron Clouds in the Surko Trap of LEPTA Facility | 319 |
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A bunch of positrons confined in a cylindrical Penning-Malmberg trap can be compressed radially by applying a rotating asymmetric dipolar electric field. An explanation of this effect presented in the report is based on the solutions of particle 3D dynamics equations in the fields of the trap taking into account the positron collisions with a neutral buffer gas. The result agrees well with experimental data obtained at the positron injector of LEPTA facility at JINR. Essential feature of the compression process is resonant character of applied rotating field and coincidence its frequency with the frequency of longitudinal positron bouncing in the trap. | ||
WEPPC036 |
Experimental Studies of Secondary Electron-Electron Emission by Vacuum Chamber Surface | |
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The experiment to measure secondary electron yield (SEY) of the samples coated with titanium nitride (TiN2) is in progress at the test-bench "Recuperator". This work is related to the problem of the electron clouds formation in vacuum chamber surface. This effect plays an important role in limiting the performance of the collider NICA. The results of the experiment to measure SEY will allow us to choose the most suitable coating material of vacuum chambers. In this experiment we compared samples of stainless steel coated with titanium nitride and uncoated ones. | ||
WEPPC044 | Positron Annihilation Spectroscopy at LEPTA Facility | 532 |
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The Low Energy Positron Toroidal Accumulator (LEPTA) at JINR proposed for generation of positronium in flight can be used for positron annihilation spectroscopy (PAS). The positron injector of the LEPTA facility can generate continuous slow positron beam of the intensity up to 1*107 s−1 at the energy in the range of a few eV to 100 keV and width of the spectrum 1-2 eV. The injector is based on radioactive 22Na isotope. The solid neon is used as moderator to generate monochromatic positron beam. It is known that positrons implanted into the matter can localize the defects of structure as vacancies, clusters of vacancies and pores. Observation of gamma quanta (511 keV) from annihilation process allows to obtain the information about the presence, concentration and kind of defects. Nowadays, the experiments with the use of slow positrons beam instead of standard isotopic sources are more popular. The progress in the creation of Doppler broadening of annihilation gamma line spectrometer will be presented here. In the simplest version, it is a set composed of a HpGe detector, a preampliefier, an ampliefier, a MC analyzer and a PC computer. This combination makes possible the observation of changes in 511 keV gamma line, calculation characteristics for PAS parameters and in effect to deduce about defects concentration and their chemical surrounding. | ||