A high-voltage negative ion based neutral beam injector is under construction at the Budker Institute of Nuclear Physics. It consists of a negative ion source, a Low Energy Beam Transport section (LEBT), which purifies the beam before acceleration, a multi-electrode single-aperture beam accelerator, a negative ion neutralizer and a magnetic separator with beam energy recuperators. The test stand to study the main injector components, consisting of the negative ion source and LEBT, the high voltage platform and the accelerator with beam transport section was launched in 2019. The initial experiments on the negative ion beam production, acceleration and 180 keV transport were tested. The power load to the acceleration tube electrodes and the data on the transported beam parameters, measured at the several positions and at the beam dump calorimeter are presented. The beam transport efficiency as a function of various ion source and LEBT parameters are presented and discussed.

A prototype of a powerful high-voltage neutral beam injector, based on acceleration of negative hydrogen ions and their neutralization, is under development at Budker Institute of Nuclear Physics (BINP). The design of the BINP high-voltage injector includes several innovative components, important for injector operation stability and overall efficiency. It includes a multi-aperture long-pulse surface-plasma negative ion source with thermostabilized grid, ithe magnetic system with concaved field lines in the ion-optic system (IOS) and the distributed cesium deposition system. The injector scheme incorporates a wide-aperture low-energy beam transport (LEBT) section, plasma target for negative ionneutralization, and recuperators of non-neutralized ions. Several test stands were constructed at BINP for injector component studies. This paper describes the results of experiments on negative ion beam production, transport through LEBT, ion acceleration to energy up to 240 keV and transport through the high voltage beam transport (HEBT) section to the distance ∼10 m from the source. The parameters of the transported beam, which were measured at several points along the beam line and at the beam dump calorimeter, are presented. The beam transport efficiency as a function of various ion source, LEBT and HEBT parameters is measured and compared with the calculated values. The results dof plasma neutralization target study are presented as well.

The Budker Institute of Nuclear Physics (BINP) project of the VEPP-2000 electron-positron Round Colliding Beams in the energy range 2*(0,25 ÷ 1) GeV has an average synchrotron radiation (SR) power of up to 1,0 kW/m at maximum currents Ie- = Ie+ = 200 mA. An overview of the VEPP-2000 complex vacuum system after the upgrade of injection complex at BINP is described here. This paper presents the dependences of photodesorption yield for aluminum and lifetime versus accumulated dose for future SRF "SKIF" (Siberian Research Facility "SKIF").

The experiments on negative hydrogen ion beam production in a multi-aperture long-pulse surface-plasma source are described. H-ions are produced on the surface of a plasma grid covered by cesium and illuminated by fast plasma particles. The source uses a radio-frequency driver to generate plasma. A composite magnet system made of external permanent magnets confines and filters electrons in the plasma region, and deflects them in the extraction area. A multiaperture, multi-electrode ion optical system is used for beam formation. The electrode heating and cooling during long pulses is accomplished by circulating a heat transfer fluid through channels drilled in the electrodes bodies. H-ions extraction through a single aperture and 21 apertures was performed and studied. A stable H- beam with the current up to 0.7 A, energy up to 74 kV, and pulse duration up to 7 s was routinely obtained

Two neutral beam injectors have been developed for plasma heating on COMPASS-D tokamak (Institute of Plasma Physics, Prague). The 4-electrodes multihole ion-optical system with beam focusing was chosen to provide the low divergence 300 kW power in both deuterium and hydrogen atoms. The accelerating voltage is 40 kV at extracted ion current up to 15 A. The power supply system provides the continuous and modulated mode of the beam injection at a maximal pulse length 300 ms. The optimal arrangement of the cryopanels and the beam duct elements provides sufficiently short-length beamline which reduces the beam losses. The evolution of the impurities and molecular fraction content is studied in the process of the high voltage conditioning of the newly made ion sources. Two injectors of the same type have been successfully tested and are ready for operation at tokamak in IPP, Prague.

The status of a unique 2.0MeV, 10mA proton tandem accelerator with vacuum insulation is presented. The accelerator is intended to be used in facilities generating resonant gamma rays for explosives detection and epithermal neutrons for boron neutron-capture therapy of brain tumors. A magnetically coupled DC voltage multiplier derived from an industrial ELV-type electron accelerator is used as a high voltage source for the accelerator. A dc high current negative ion source has been developed for injection into the tandem. In the tandem accelerator there is set of nested potential electrodes with openings which form a channel for accelerating the negative hydrogen ion beam and subsequently accelerating the proton beam after stripping in the gas target. The electrodes are connected to a high voltage feedthrough insulator to which required potentials are applied from the high voltage power supply by means of a resistor voltage divider. In the paper the first experimental results obtained with the vacuum insulated tandem accelerator are also given.

The results of the tandem commissioning as initial high voltage tests and beam injection experiments on BINP proton tandem-accelerator are given. The accelerator is intended to be used in facilities generating resonant gamma rays for explosives detection and epithermal neutrons for boron neutron-capture therapy of brain tumors. A magnetically coupled DC voltage multiplier derived from an industrial ELVtype electron accelerator is used as a high voltage source for the accelerator. A dc high-current negative ion source has been developed for injection into the tandem. In the tandem accelerator there is set of nested potential electrodes with openings which form a channel for accelerating the negative hydrogen ion beam and subsequently accelerating the proton beam after stripping in the gas target. The electrodes are connected to a high voltage feedthrough insulator to which required potentials are applied from the high voltage power supply by means of a resistor voltage divider.

The results of the tandem commissioning as initial high voltage tests and beam injection experiments on BINP proton tandem-accelerator are given. The ac- celerator is intended to be used in facilities generat- ing resonant gamma rays for explosives detection and epithermal neutrons for boron neutron-capture ther- apy of brain tumors. A magnetically coupled DC voltage multiplier derived from an industrial ELV- type electron accelerator is used as a high voltage source for the accelerator. A dc high-current nega- tive ion source has been developed for injection into the tandem. In the tandem accelerator there is set of nested potential electrodes with openings which form a channel for accelerating the negative hydrogen ion beam and subsequently accelerating the proton beam after stripping in the gas target. The electrodes are connected to a high voltage feedthrough insulator to which required potentials are applied from the high voltage power supply by means of a resistor voltage divider.

HIRFL-CSR, a new ion cooler-storage ring, is under construction at IMP. It is equipped with two electron cooling devices. The technical parameters of the project will be reviewed briefly. The HIRFL-CSR cooler could be a new generation cooler with some unique features such as a new electron gun capable to produce hollow electron beam, electrostatic bending plates and a new structure of solenoid coils at the cooling section. The commissioning of the first cooler with electron beam at IMP was completed. The second cooler with energy 300keV is under final assembling.

Novel 2.5 MeV, 40 mA tandem accelerator is presented and discussed. Results of work of ion source and choice of ion optical channel and charge-exchange target are shown. Results of experiments on study of high voltage durability of 45 mm vacuum gap with large square electrodes and determination of dependence of autoemission current/on electric field intensity are reported.

Original 2.5 MeV, 40 mA proton tandem accelerator for the neutron therapy facility is described. The results of computer simulations of high current hydrogen negative ions beam transmission through the special geometry of potential electrodes with vacuum insulation are presented. The results of experiments with prototype vacuum insu- lation tandem accelerator are given also. Various charge- exchange targets are considered. Namely, targets are gas target with outward pumping, gas target with pumping inside of high-voltage electrode.

The performance of the vacuum system of the Large Hadron Collider will depend critically on the synchrotron radiation induced gas desorption and on the readsorption of molecules on the cold surfaces. The present design of the system is based on a so-called beam screen inserted in the 1.9 K cold bore of the magnets. Gas molecules desorbed will therefore readsorb on the beam screen which is held at a temperature between 5 and 20 K. Pumping slots in the beam screen enable some of the desorbed gas to be pumped onto the 1.9 K surface of the cold bore.