RuPAC2014 - List of Authors (Sidorin, A.A.)

Paper	Title	Page
TUCA04	Mechanism of Compression of Positron Clouds in the Surko Trap of the LEPTA Facility	20
	M.K. Eseev, E.V. Ahmanova, A.G. Kobets, I.N. Meshkov, O. Orlov, A.A. Sidorin, S. Yakovenko JINR, Dubna, Moscow Region, Russia M.K. Eseev NAFU, Arkhangelsk, Russia A.G. Kobets IERT, Kharkov, Ukraine
	Results from experimental studies of plasma storage in the Surko trap at the LEPTA facility are presented. The number of stored particles is found to increase substantially when using the socalled "rotating wall" method, in which a transverse rotating electric field generated by a cylindrical segmented electrode cut into four pairs is applied to the positrons storage region. The conditions of transverse compression of the plasma bunch under the action of the rotating field and buffer gas are studied. The optimal storage parameters are determined for these experimental conditions. Mechanisms of the action of the rotating field and buffer gas on the process of positron clouds storage are presented.

TUPSA23	LEPTA - the Facility for Fundamental and Applied Research	83
	E.V. Ahmanova, V.M. Drobin, P. Horodek, A.G. Kobets, I.N. Meshkov, O. Orlov, A.Yu. Rudakov, V.V. Seleznev, A.A. Sidorin, S. Yakovenko JINR, Dubna, Moscow Region, Russia M.K. Eseev NAFU, Arkhangelsk, Russia
	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 last results are presented in this report: studies of e⁺/e⁻ dynamics in trap, e⁺ beam in the ring, LEPTA upgrade (vacuum, e⁺ source with cryocooler), Channel for PAS.

TUPSA24	Project of Electron Cooler for NICA Collider	85
	A.A. Sidorin, E.V. Ahmanova, A.G. Kobets, I.N. Meshkov, O. Orlov, A.Yu. Rudakov, V.I. Shokin JINR, Dubna, Moscow Region, Russia A.G. Kobets IERT, Kharkov, Ukraine I.N. Meshkov JINR/DLNP, Dubna, Moscow region, Russia
	Electron cooling system (ECS) of the NICA collider is designed to form the required parameters of the ion beam at energy of the experiment in the range of 1 - 4.5 GeV/amu that requires energy cooling electrons from 0.5 to 2.5 MeV. To achieve the required energy of the electrons all elements of ECS are placed in tanks filled with sulfur hexafluoride (SF6) under pressure of 6 atm. For testing items ECS elements the test bench "Recuperator" is used. This paper presents the results of testing the prototype elements of the ECS and the first results of technical design of ECS.

WEPSB32	Positron Annihilation Spectroscopy at LEPTA Facility	231
	P. Horodek, I.N. Meshkov JINR/DLNP, Dubna, Moscow region, Russia A.G. Kobets, O. Orlov, A.A. Sidorin JINR, Dubna, Moscow Region, Russia
	Since 2009 year the LEPTA facility at Joint Institute for Nuclear Research in Dubna is operated with positron beam. Today it is developed into two directions. The first one is getting orthopositronium flux in flight. Slow positrons from 22Na source are accumulated in Surko trap and then are injected into the ring where they should overlap with electrons from the sigle-pass electron beam. In this way the flux of orthopositronium atoms will appear and will be observed in the process of registration of gamma quanta from annihilation process. The second group of works focuses on using the positron injector for Positron Annihilation Spectroscopy (PAS) applications. This method is dedicated to detection of structural defects as vacancies in the solid body lattice. The latest progress of this technique is strictly connected with measurements of PAS characteristics using positron beams. The progress in the LEPTA development, the first results obtained in the PAS, idea and actual state of works concerning the construction of the pulsed positron beam will be presented. The creation of pulsed positron beams is the modern tendency in the PAS domain. It allows to measure the lifetimes of annihilating positron in the depth ca. 1 mkm under the surface. It makes possible the identification of kind of defect.

Paper

Title

Page

Mechanism of Compression of Positron Clouds in the Surko Trap of the LEPTA Facility

20

M.K. Eseev, E.V. Ahmanova, A.G. Kobets, I.N. Meshkov, O. Orlov, A.A. Sidorin, S. Yakovenko
JINR, Dubna, Moscow Region, Russia
M.K. Eseev
NAFU, Arkhangelsk, Russia
A.G. Kobets
IERT, Kharkov, Ukraine

Results from experimental studies of plasma storage in the Surko trap at the LEPTA facility are presented. The number of stored particles is found to increase substantially when using the socalled "rotating wall" method, in which a transverse rotating electric field generated by a cylindrical segmented electrode cut into four pairs is applied to the positrons storage region. The conditions of transverse compression of the plasma bunch under the action of the rotating field and buffer gas are studied. The optimal storage parameters are determined for these experimental conditions. Mechanisms of the action of the rotating field and buffer gas on the process of positron clouds storage are presented.

TUPSA23

LEPTA - the Facility for Fundamental and Applied Research

83

E.V. Ahmanova, V.M. Drobin, P. Horodek, A.G. Kobets, I.N. Meshkov, O. Orlov, A.Yu. Rudakov, V.V. Seleznev, A.A. Sidorin, S. Yakovenko
JINR, Dubna, Moscow Region, Russia
M.K. Eseev
NAFU, Arkhangelsk, Russia

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 last results are presented in this report: studies of e⁺/e⁻ dynamics in trap, e⁺ beam in the ring, LEPTA upgrade (vacuum, e⁺ source with cryocooler), Channel for PAS.

TUPSA24

Project of Electron Cooler for NICA Collider

85

A.A. Sidorin, E.V. Ahmanova, A.G. Kobets, I.N. Meshkov, O. Orlov, A.Yu. Rudakov, V.I. Shokin
JINR, Dubna, Moscow Region, Russia
A.G. Kobets
IERT, Kharkov, Ukraine
I.N. Meshkov
JINR/DLNP, Dubna, Moscow region, Russia

Electron cooling system (ECS) of the NICA collider is designed to form the required parameters of the ion beam at energy of the experiment in the range of 1 - 4.5 GeV/amu that requires energy cooling electrons from 0.5 to 2.5 MeV. To achieve the required energy of the electrons all elements of ECS are placed in tanks filled with sulfur hexafluoride (SF6) under pressure of 6 atm. For testing items ECS elements the test bench "Recuperator" is used. This paper presents the results of testing the prototype elements of the ECS and the first results of technical design of ECS.

WEPSB32

Positron Annihilation Spectroscopy at LEPTA Facility

231

P. Horodek, I.N. Meshkov
JINR/DLNP, Dubna, Moscow region, Russia
A.G. Kobets, O. Orlov, A.A. Sidorin
JINR, Dubna, Moscow Region, Russia

Since 2009 year the LEPTA facility at Joint Institute for Nuclear Research in Dubna is operated with positron beam. Today it is developed into two directions. The first one is getting orthopositronium flux in flight. Slow positrons from 22Na source are accumulated in Surko trap and then are injected into the ring where they should overlap with electrons from the sigle-pass electron beam. In this way the flux of orthopositronium atoms will appear and will be observed in the process of registration of gamma quanta from annihilation process. The second group of works focuses on using the positron injector for Positron Annihilation Spectroscopy (PAS) applications. This method is dedicated to detection of structural defects as vacancies in the solid body lattice. The latest progress of this technique is strictly connected with measurements of PAS characteristics using positron beams. The progress in the LEPTA development, the first results obtained in the PAS, idea and actual state of works concerning the construction of the pulsed positron beam will be presented. The creation of pulsed positron beams is the modern tendency in the PAS domain. It allows to measure the lifetimes of annihilating positron in the depth ca. 1 mkm under the surface. It makes possible the identification of kind of defect.