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.

The Circular Polarizing Undulator (CPU) had been built by the joint team of BINP (Novosibirsk, Russia) and ANL (Argonne, USA) for X-rays generation with variable polarization (circular and linear). This Undulator has about 4 m long. It consists of two main windings with maximal currents 1600A (about 30kW power) and 400A (4kW power) and additional correcting low-current windings. The task of powering CPU requires to design a special power supply. The main requirement to such a power supply is forming the current with polarity switching frequency up to 10 Hz. The high-current channels are connected to the power line by diode rectifiers with a damped LC-filters and consist of diode bridge rectifier, PWM-controlled IGBT inverters, step-down transformers, diode high-frequency H-type rectifiers with LC-filters and output high-current inverters. The low-current channels are fed from special low-voltage rectifiers. They also performed with PWM control. All the channels are controlled independently and are equipped with precision current monitors. The report describes the principle of operation of the power supplies and the obtained results.

For the purpose of a beam emission spectroscopy diagnostic in plasma fusion devices the Diagnostic Neutral Beam Injectors (DNBI) are used. The typical beam parameters of these DNBIs are as follows: neutral beam energy ranges from 20 kV up to 55 kV, equivalent neutral beam current is 1-3 A, beam on time varies from 50 msec up to several seconds. The pulse repetition rate is typically about one pulse per 5-20 minutes. For the above mentioned parameters, one can easily calculate that the energy carried out by this beam has a scale of 20 to 200 kJ. The high voltage modulator (HVM) family was developed in the Budker Institute of Nuclear Physics, Novosibirsk, to supply the DNBIs dedicated for this task. One type of them is intended to provide 2 sec. shots with an HVM output current up to 3 A, another one for 50 msec. shots with a current up to 10 A. Two modes of DNBI operation are used: a quasi-continuous beam and 100% amplitude modulated beam with programmable durations of time intervals of the ON and OFF states. In addition, these HVMs have relatively small energy stored by its output reactive elements and are equipped with a fast interlock system to avoid critical damages of the DNBI grids during transient processes and when an electrical breakdown between electrodes occurs. The paper describes the circuitry, design, interlocks and solutions of HVM buffering relative to the mains. In the basic design, 10 kHz IGBT inverters with PWM and matching transformers are used to power the HVMs. One of the HVMs is installed at the TCV Tokamak (EPFL, Lausanne), another one is installed at the Alcator C-mod Tokamak, (MIT, Boston).

Linearly and circularly polarized x-rays have been very successfully applied to the study of the properties of materials. Many applications can benefit from the availability of energy-tunable, high-brilliance x-ray beams with adjustable polarization properties. A helical undulator that can generate beams of variable (linear to circular) polarization has been designed and built by the Budker Institute of Nuclear Physics and the Advanced Photon Source. The first harmonic of this 12.8-cm-period device will cover the energy range from 0.4 keV to 3.5 keV. An important feature of this fully electromagnetic device is that it will allow us to generate 100% horizontally (Kx=0) or vertically (Ky=0) plane-polarized radiation, which will enable many experiments otherwise not technically feasible. With symmetric deflection parameters (Kx=Ky), the on-axis radiation will be circularly polarized, with a user-selectable handedness. The polarization can be changed at rates up to 10 Hz.

A 2-MeV injector for the Novosibirsk high power free electron laser is described. It consists of a 300 keV electron gun, one bunching and two accelerating RF cavities with RF generators, a vacuum system, a magnetic system and a beam dump. The electron gun uses a gridded cathode and provides an electron beam with average current 55 mA, repetition rate 22.5 MHz and peak current 2.3 A. The RF system operates at 180 MHz frequency. The CW RF power supply provides up to 260 kW output power. The injector will serve as the beam source for the accelerator-recuperator of the high power free electron laser, which is under construction in Novosibirsk now.