BINP Research Articles

Recording Vavilov – Cherenkov radiation in a linear accelerator using a picosecond streak camera

Using a picosecond image converter camera with a linear sweep (PS-1/S1 streak camera developed at GPI RAS, Moscow), we have measured temporal parameters of Vavilov – Cherenkov radiation pulses. The radiation was generated by relativistic electrons passing through a quartz cone mounted on the axis of a vacuum chamber of a linear accelerator, which is a part of the VEPP-5 injection complex at the Budker Institute of Nuclear Physics, Siberian Branch of the Russian Academy of Sciences (BINP SB RAS, Novosibirsk). The data obtained in these experiments provide an insight into the processes of formation of electron bunches and their ‘quality’ in a linear accelerator prior to injection of electrons into the accumulator-cooler. A conclusion is made regarding the advisability of streak camera application in tuning the linear accelerators for optimisation of electron bunch parameters.

Photon counting detector for the personal radiography inspection system “SIBSCAN”

X-ray detectors operating in the energy integrating mode are successfully used in many different applications. Nevertheless the direct photon counting detectors, having the superior parameters in comparison with the integrating ones, are rarely used yet. One of the reasons for this is the low value of the electrical signal generated by a detected photon. Silicon photomultiplier (SiPM) based scintillation counters have a high detection efficiency, high electronic gain and compact dimensions. This makes them a very attractive candidate to replace routinely used detectors in many fields. More than 10 years ago the digital scanning radiography system based on multistrip ionization chamber (MIC) was suggested at Budker Institute of Nuclear Physics. The detector demonstrates excellent radiation resistance and parameter stability after 5 year operations and an imaging of up to 1000 persons per day. Currently, the installations operate at several Russian airports and at subway stations in some cities. At the present time we design a new detector operating in the photon counting mode, having superior parameters than the gas one, based on scintillator – SiPM assemblies. This detector has close to zero noise, higher quantum efficiency and a count rate capability of more than 5MHz per channel (20% losses), which leads to better image quality and improved detection capability. The suggested detector technology could be expanded to medical applications.

Field Measurements of Magnets for Modern SR Sources and FEL

Magnets for modern accelerators and storage rings may have a rather complex field distribution and strict quality requirements. The Budker Institute of Nuclear Physics (Novosibirsk, Russia) is a well-known producer of magnets for various accelerator projects worldwide. This paper describes our magnet measurement facility with examples of NSLS-II booster magnets, small-aperture X-FEL quadrupoles, and PETRA-III dipoles. NSLS-II booster dipoles have quadrupole and sextupole components with a rather high field quality of $1\cdot 10^{-3}$ in the good field region of ±2 cm, providing booster operation at energy from 170 MeV to 3.15 GeV with a 2-Hz repetition rate. We designed a special bench with a ceramic rotation coil to measure X-FEL quadrupoles. The equipment provided measurements of the magnetic axis with accuracy better than 5 $\mu\text{m}$ . We used the system of three temperature-stabilized Hall sensor arrays distributed vertically to obtain a three-dimensional field map from a single measurement of PETRA-III dipole magnets.

The study of neutron burst shape of a neutron tube driven by dispenser cathode

A slim-shaped portable DD-neutron generator is developed at Budker institute of Nuclear Physics. The generator is a combination of Cockcroft–Walton voltage multiplier and a sealed gas-filled neutron tube driven by dispenser cathode. Neutron burst shape in pulsed mode of neutron tube operation is measured with stroboscopic time spectrometry, implemented on scintillation detector, and modeled with Comsol Script 1.3 and Comsol Multiphysics 3.5. Modeling appears to be in good agreement with experimental results. Measured pulse rise and fall times are 110ns and 100ns respectively.

Helical mirrors for active plasma flow suppression in linear magnetic traps

A novel concept of helical mirror confinement with active axial and radial plasma flow control is discussed. The idea relies on the retarding force that appears when biased plasma experiences rotation in crossed electrical and helical mirror magnetic fields. Preparations for its experimental study started in Budker Institute of Nuclear Physics, Novosibirsk. Possible parameter space for a concept-exploration-class device SMOLA is identified. Details of numerical optimization of the magnetic structure of the device are presented. The main physical task for the SMOLA experiment will be direct demonstration of the helical mirror performance in simple experimental conditions at reasonably low plasma parameters.

Recording the synchrotron radiation by a picosecond streak camera for bunch diagnostics in cyclic accelerators

A PS-1/S1 picosecond streak camera with a linear sweep is used to measure temporal characteristics of synchrotron radiation pulses on a damping ring (DR) at the Budker Institute of Nuclear Physics (BINP) of the Siberian Branch of the Russian Academy of Sciences (Novosibirsk). The data obtained allow a conclusion as to the formation processes of electron bunches and their ‘quality’ in the DR after injection from the linear accelerator. The expediency of employing the streak camera as a part of an optical diagnostic accelerator complex for adjusting the injection from a linear accelerator is shown. Discussed is the issue of designing a new-generation dissector with a time resolution up to a few picoseconds, which would allow implementation of a continuous bunch monitoring in the DR during mutual work with the electron-positron colliders at the BINP.

Inductively driven surface-plasma negative ion source for N-NBI use (invited).

The long-pulse surface-plasma source prototype is developed at Budker Institute of Nuclear Physics for negative-ion based neutral beam injector use. The essential source features are (1) an active temperature control of the ion-optical system electrodes by circulation of hot thermal fluid through the channels, drilled in the electrode bodies, (2) the concaved transverse magnetic field in the extraction and acceleration gaps, preventing the electrons trapping and avalanching, and (3) the directed cesium deposition via distribution tubes adjacent to the plasma grid periphery. The long term effect of cesium was obtained just with the single cesium deposition. The high voltage strength of ion-optical system electrodes was improved with actively heated electrodes. A stable H(-) beam with a current ∼1 A and energy 90 keV was routinely extracted and accelerated.

Multifunctional X-ray Lithography Station at VEPP-3

The multifunctional X-ray lithography “LIGA” station on beamline 0 at the VEPP-3 synchrotron source is part of the shared-use center “Siberian Synchrotron and Terahertz Radiation Center” (SSTRC) in Budker Institute of Nuclear Physics (BINP, Novosibirsk, Russia). The station is intended to exposure of resist layers on substrates of different shape and lateral dimensions of 1 to 10cm. The development of process and re-equipment of the station goes forward, continuously. In this work we consider the current capabilities of the station; examples of microstructures fabricated are presented.

Upgrade of the Detector for Imaging of Explosions

Methods of dynamic imaging of explosions at a synchrotron radiation (SR) beam and small-angle X-ray scattering experiments with exploding samples are being developed in the Siberian Synchrotron Radiation Center (SSRC) at the Budker Institute of Nuclear Physics for more than fifteen years. The detector for imaging of explosions (DIMEX) was developed for these purposes and successfully operating at the beam line 0 at the VEPP-3 storage ring and at the beam line 8 at the VEPP-4M storage ring. The DIMEX is based on gas technology and allow to measure SR flux as a function of position and time with spatial resolution of ∼200 μm (FWHM), maximum frame rate of 2MHz and time resolution of ∼80ns. Maximum value of the SR flux that can be measured by the present detector corresponds to ∼5000 photons/(channel*bunch) (20 keV average energy, channel area 0.1x0.5 mm2, bunch revolution frequency 4MHz). Maximum number of frames that can be stored in the present detector is 32 and the number of channels with 0.1mm width is 512. In order to significantly improve the precision of data obtained by the DIMEX an upgrade of the detector has been started. The electronics of the gaseous version of the detector has been changed such that the new detector is able to operate with frame rate of 8MHz and store data in up to 100 frames. A new ASIC was developed for this purpose called DMXG64A that includes 64 channels with low noise integrator and 100 analogue memory cells in each channel. Input charge can be stored to and read out from analogue cells with maximum frequency 10MHz. This new version of the detector is called the DIMEX-G and is planned to be used at the VEPP-3 storage ring and for SAXS studies at the VEPP-4M storage ring. For imaging of explosions at the beam line 8 at the VEPP-4M storage ring, where SR flux is expected to be about 10-100 times higher than at the VEPP-3, a new detector based on Si micro-strip technology is being developed. Si micro-strip sensors with special design have been manufactured by Hamamatsu Photonics company. Each sensor contains 1024 30mm long strips with 50μm pitch. The sensor thickness is 320μm and it will be positioned at an angle of 1.7 degrees with respect to the SR beam plane in order to get effective Si thickness along the beam close to 10mm. The new detector called DIMEX-Si will have spatial resolution of 50μm (FWHM) and time resolution close to 10ns. The new ASIC is under development for this project that will allow to operate with the frame rate of 50MHz and record maximum charge that corresponds to the flux close to 106 photons/(chan*bunch), i.e. about 100 times higher than with present detector.

Investigation of the Aluminum Nitride Formation During the Aluminum Nanopowder Combustion in Air

The phase formation sequences, intermediate and final products of aluminum nanopowder combustion are studied. The experiments were performed in the Budker Institute of Nuclear Physics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, at the “Precision Diffractometry II” station (SR beamline No. 6 of the VEPP-3 electron storage ring). The main combustion product was found to be aluminum nitride. In the combustion of aluminum nanopowder aluminum γ-oxide is the first to form, and aluminum nitride arises next. The formation of aluminum nitride probably occurs by successive replacement of oxygen by nitrogen from the aluminum oxide. The use of synchrotron radiation with high photon flux made it possible to determine with moderate time resolution the sequence of stages of formation of crystalline products during combustion of the aluminum nanopowder.

Synchrotron Radiation Research and Application at VEPP-4

VEPP-4 is a multipurpose storage ring facility at Budker Institute of Nuclear Physics (Novosibirsk, Russia) with several research programs including high energy physics in colliding beam mode, nuclear physics, synchrotron radiation, accelerator physics study, etc. The paper discusses VEPP-4 activities relating to generation and application of synchrotron radiation not only for SR user community but for beam diagnostics in storage ring as well.

The Research of the Superconducting Undulator Prototype with Neutral Poles and Features of the Magnetic Field Distribution in it

The article describes superconducting undulator prototype with neutral poles designed and fabricated in Budker Institute of Nuclear Physics. In the upper half of the undulator even-numbered poles have a core with a winding and odd - core without winding. In the lower half vice versa. This design allows to provide more accurate period and reduces the probability of mechanical movements caused by the action of ponderomotive forces leading to quench of superconductivity. The article also describes the features of the magnetic field distribution in such windings configuration.

Synchrotron Radiation Method for Study the Dynamics of Nanoparticle Sizes in Trinitrotoluene During Detonation

This work presents the results of experiments using synchrotron radiation from the VEPP-4M accelerator complex at Budker Institute of Nuclear Physics. Dynamic of small-angle X-ray scattering of synchrotron radiation was implemented on the synchrotron radiation beamline 8-b. Here given beam parameters and described elements of the station and detector system. The distance from the axis of the explosive charge to the detector was 3432 mm. The strip size of the detector DIMEX was 0.1 mm. Thus, a single channel of the detector DIMEX in these experiments corresponded to the scattering angle 2θ: 1 detector channel = 0.02914 mrad. The SAXS measurement technique on this station enables detection of nanoparticles ranging in size from 2 nm to 200 nm with exposure time 73 ps for one frame. It is possible to record 100 frames with interval 100 ns. In this work used TNT with 30 mm in diameter and 55 mm in length. Ultra fine diamonds of 2 nm size was detected behind the detonation front, after that the average size of particles increases up to 5–6 nm during few microseconds.

Radiation treatment of the ceramic and polymer implants

Implants are used in medical practice during decades. The ceramic implants are the new trend in medicine. The polymer implants are used for many years, and they are mainly sterilized by the radiation treatment. The article describes the new ceramic and polymer implants that were treated in the Budker Institute of Nuclear Physics.

Application of Synchrotron Radiation for In Situ XRD Investigation of Zirconium Hydrides Formation at Gas-phase Hydrogenation

The zirconium alloy (Zr1%Nb) samples with a micron-thick nickel layer were investigated for hydrogen sorption ability. Hydrogenation was carried out by gas phase method at temperatures of 350, 450 and 550° C. Hydrogen pressure in chamber was 1 atm. Hydrogen sorption curves were obtained on the automated complex Gas Reaction Controller. In situ X-ray diffraction measurements of the process of hydrogen saturation of samples were carried out at the station “Precision diffractometry» at Siberian Synchrotron and Terahertz Radiation Center of the Budker Institute of Nuclear Physics. Hydrogen absorption rate by Zr1%Nb alloy increases by order of magnitude with increasing temperature. The phase transitions significantly affect the rate of hydrogen absorption at constant temperature. Measurements were performed using SR from the VEPP-3 storage ring.

Synchrotron Radiation Applications in the Siberian Synchrotron and Terahertz Radiation Center

The Siberian Synchrotron and Terahertz Radiation Center (SSTRC, Budker Institute of Nuclear Physics (INP), Novosibirsk, Russian Federation) is one of the oldest and main Russian centers for synchrotron radiation applications. The center combines research efforts of numerous scientific groups, mostly from institutes and universities of the Novosibirsk Scientific Center (Siberian Branch of the Russian Academy of Sciences) as well as researchers from all over Russia. The center provides access to the most popular synchrotron radiation applications and research techniques including the unique ones in the world. The synchrotron radiation (SR) is produced by VEPP-3 and VEPP-4M storage rings of the INP. Most of the activities of SSTRC is devoted to developing original approaches for synchrotron radiation usage. The report covers activity on synchrotron radiation applications at the Siberian Synchrotron and Terahertz Radiation Center as well as some bright results of recent research.

Nsls-II Boster

The National Synchrotron Light Source II is a third generation light source, which was constructed at Brookhaven National Laboratory. This project includes a highly-optimized 3 GeV electron storage ring, linac preinjector, and full-energy synchrotron injector. Budker Institute of Nuclear Physics built and delivered the booster for NSLS-II. The commissioning of the booster was successfully completed. This paper reviews fulfilled work by participants.

Impact of neutron radiation on the viability of tumor cells cultured in the presence of boron-10 isotope

To investigate the impact of a neutron beam formed with the accelerator-based epithermal neutron source designed at the G.I. Budker Institute of Nuclear Physics (INP) on the viability of human and animal tumor cells cultured in the presence of boron-10 isotope. Human U251 and T98G glioma cells and Chinese hamster CHO-K1 and V-79 cells were incubated at various concentrations in the culture medium containing 10B-enriched L-boronophenylalanine. The cells were irradiated with a neuron beam using the accelerator-based epithermal neuron source. A clonogenic assay was used to evaluate the viability of the irradiated cells. The absorbed doses obtained from elastic scattering of fast neutrons by substance nuclei and the doses obtained from boron neutron capture were calculated using the NMS code. The absorbed doses of gamma-radiation were measured with a mixed radiation dosimeter. The viability of boron-containing and intact human U251 and T98G cell lines and Chinese hamster CHO-K1 and V-79 cells was analyzed after neutron beam radiation. Irradiation of all four cell lines were cultured in the presence of 10B was shown to reduce their colony-forming capacity compared with the control. Elevated boron levels in the culture medium resulted in a significant decrease in the proportion of survived cells. Radiation had the most pronounced impact on the proliferative capacity of the human U251 glioma cell lines. The cultures of human tumor cells and mammalian cells demonstrated that the neutron beam formed with the accelerator-based epithermal neutron source designed at the INP, was effective in reducing the viability of tumor cells in the presence of 10B.

Progress in Mirror-Based Fusion Neutron Source Development.

The Budker Institute of Nuclear Physics in worldwide collaboration has developed a project of a 14 MeV neutron source for fusion material studies and other applications. The projected neutron source of the plasma type is based on the gas dynamic trap (GDT), which is a special magnetic mirror system for plasma confinement. Essential progress in plasma parameters has been achieved in recent experiments at the GDT facility in the Budker Institute, which is a hydrogen (deuterium) prototype of the source. Stable confinement of hot-ion plasmas with the relative pressure exceeding 0.5 was demonstrated. The electron temperature was increased up to 0.9 keV in the regime with additional electron cyclotron resonance heating (ECRH) of a moderate power. These parameters are the record for axisymmetric open mirror traps. These achievements elevate the projects of a GDT-based neutron source on a higher level of competitive ability and make it possible to construct a source with parameters suitable for materials testing today. The paper presents the progress in experimental studies and numerical simulations of the mirror-based fusion neutron source and its possible applications including a fusion material test facility and a fusion-fission hybrid system.

Master controller of a high-voltage power unit source of an electron beam welding device

This paper describes the structure and control algorithms of a controller of a high-voltage source with an output voltage of 60 kV and a power of up to 30 kW. The source is designed to be used as part of a power unit of an electron-beam welding device developed at the Budker Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of Sciences (BINP SB RAS). High-quality welds require a stable electron beam energy. Herewith, a standard operation mode is quick and deep modulation of the electron current. The problem of achieving high-quality control and limiting the transient distortions of output voltage of the source is solved. The error of establishing and stabilizing the output voltage is 0.1%, which allows obtaining high-quality welding. Transient distortions at 100% modulation of the load current do not exceed the value of ±1%, which, along with fast reaction of the source to a load breakdown (energy released during breakdown is smaller than 15 J), protects the welded parts and elements of the gun from being damaged by an electron beam.