ABSTRACT
The incoherent Thomson scattering diagnostic with multiple lines of sight is installed at the gas dynamic trap (GDT) for measurements of radial profiles of the plasma electron temperature and density. The diagnostic is built on the Nd:YAG laser operating at 1064 nm. The laser input beamline is provided with an automatic system for alignment status monitoring and correction. The collecting lens uses â¼90° scattering geometry having 11 lines of sight in total. Presently, six of them (covering the full plasma radius from the axis to the limiter) are equipped with high etendue (f/2.4) interference filter spectrometers. The design of the spectrometer's data acquisition system based on the "time stretch" principle allowed for the 12 bits vertical resolution with a sampling rate of 5 GSample/s and a maximum sustainable measurement repetition frequency of 40 kHz. The repetition frequency is the crucial parameter for the study of plasma dynamics with a new pulse burst laser to be started in early 2023. Results of the diagnostic operation in several GDT campaigns show that radial profiles are routinely delivered with the typical observation error of 2%-3% for Te ⩾ 20 eV in a single pulse. After Raman scattering calibration, the diagnostic is capable to measure the electron density profile with the resolution ne (min)≃4â 1018m-3 and error bars of 5%.
ABSTRACT
A spectrometer based on a linear array photomultiplier tube (PMT) has been developed and calibrated. A 0.635 m focal length Czerny-Turner monochromator combined with a coupling optics provides an image of a narrow 0.5 nm spectral range with a resolution of 0.015 nm/channel on a 32-anode PMT. The system aims at spectroscopy of D(α) or H(α) lines emitted by a diagnostic atomic beam in a plasma (primarily a motional Stark effect diagnostics). To record a low photon flux of â¼10(6) s(-1) per channel with the time resolution of 100 µs, a pulse counting approach has been used. Wideband amplifiers scale single-electron pulses and transmit them to a digital data processing core hardwired in a programmable logic matrix. Calibrations have shown that the aberration-limited instrument function fits to a single detector channel of 1 mm width. Pilot results of passive measurements of D(α) light emission from the plasma confined in a magnetic trap are presented.
ABSTRACT
The design and main characteristics of 14-channel dispersion interferometer for plasma profile measurement and control in TEXTOR tokamak are presented. The diagnostic is engineered on the basis of modular concept, the 10.6 microm CO(2) laser source and all optical and mechanical elements of each module are arranged in a compact housing. A set of mirrors and retroreflectors inside the TEXTOR vacuum vessel provides full coverage of the torus cross section with 12 vertical and two diagonal lines of sight, no rigid frame for vibration isolation is required. Results of testing of the single-channel prototype diagnostic and the pilot module of the multichannel dispersion interferometer are presented.
ABSTRACT
One year experience of dc H(-) source operation at 2 MeV tandem accelerator is described. The source delivers H(-) ion beams with controlled current in the range of 1-8 mA and energy up to 25 keV. Normalized 1 rms emittance for 8 mA beam is less than 0.2 pi mm mrad. Negative ions are produced on the cesiated anode of the Penning discharge, driven by plasma injection from the hollow cathode inserts.
ABSTRACT
A 2 MeV proton tandem accelerator with vacuum insulation was developed and first experiments are carried out in the Budker Institute of Nuclear Physics (Novosibirsk). The accelerator is designed for neutron production via reaction (7)Li(p,n)(7)Be for the boron neutron-capture therapy of the brain tumors, and for explosive detection based on 9.1724 MeV resonance gamma, which are produced via reaction (13)C(p,gamma)(14)N, absorption in nitrogen.
ABSTRACT
A new fast beam profile monitor has been developed at the Budker Institute of Nuclear Physics. This monitor is based on the Hamamatsu multianode photomultiplier with 16 anode strips and provides turn-by-turn measurement of the transverse beam profile. The device is equipped with an internal memory, which has enough capacity to store 131,072 samples of the beam profile. The dynamic range of the beam profile monitor allows us to study turn-by-turn beam dynamics within the bunch charge range from 1 pC up to 10 nC. Using this instrument, we have investigated at the VEPP-4M electron-positron collider a number of beam dynamics effects which cannot be observed by other beam diagnostics tools.
