V. I. Shvedunov

Production of the isotope 18F in the reaction 23Na(γ,αn)18F at E b = 55 MeV

The activity of 18F that was produced in the 23Na(γ,αn)18F reaction with the maximum bremsstrahlung energy Eb = 55 MeV was measured.

Using accelerated electron beams for the radiation processing of foodstuffs and biomaterials

The Department of Accelerator Physics and Radiation Medicine of Moscow State University’s Faculty of Physics conducts experiments on the radiation processing of food products and the development of a new technology for the combined sterilization of bone implants, based on the joint action of different sterilizing factors (radiation and sterilization) in a gaseous medium. Radiation processing of potato tubers and bone implants is performed using accelerated electron beams with energies of 1 MeV. The results from experimental investigations along these lines are presented.

Measuring the atomic numbers of unknown objects on a electron accelerator with variable energy

A series of measurements on the electron accelerator with variable energy is performed to verify experimentally the possibility of measuring the atomic numbers of unknown objects. The results are in good agreement with earlier conclusions on the need to use more than two energies. The standard deviation of the measured values of atomic number from the expected values is 11.8, confirming the sufficient reliability of the method.

A high-intensity bremsstrahlung source for investigating radiation stability of optical samples for excimer laser windows

A bremsstrahlung X-ray source (hv ≤ 600 keV) was developed on the basis of CW electron LINAC. It provides an absorbed dose rate of ∼30 Gy/s within an area of ∼2.5 cm2. The radiation stability of quartz glasses and crystals for excimer lasers windows was investigated.

Compact linear electron accelerator for radiation technologies

A prototype of a commercial compact continuous-beam linear electron accelerator has been designed and constructed. With its energy of 600 keV and a beam with 30 kW maximum power, the accelerator can be used in various radiation technologies. Its compact size, easy operation, reliability, wide adjustment range for the main parameters, and possible local shielding allow it to be integrated into the majority of radiation technology processes.

Coherent radiation diagnostics of parameters of nanostructures at electron accelerators

The possibility of observing and diagnosing parameters of nanoobjects in a substance by using coherent X-ray radiation arising from the direct interaction of accelerated electrons with the object of interest is discussed. It is analytically shown that analysis of the generated radiation allows the microstructural features of the nanoobject to be studied. To illustrate the main conclusions, coherent radiation generated by relativistic electron scattering on fullerene is considered.

High efficiency x-ray bremsstrahlung sources

We propose to generate X-rays by having an electron beam in a magnetic field cross thin foil radiators multiple times. We report that our simulation and analytic results agree and indicate that the X-ray yield will be at least doubled over that from a single, equivalently thick, target.

Free electron laser-FEL-study in Institute of Nuclear Physics of MSU

The possibility of creation of a source of coherent shortwave radiation on the basis of the RM of Moscow State University (MSU) facility was considered. The RM is designed to obtain accelerated electrons with a variable energy of 7-180 MeV at high quality of beam: the homogeneity of energy is 0.0001, the beam emittance is not higher than 0.01 mm.mrad. The beam current is a continuous sequence of electron pulses with the duration of 3-4 ps following at a frequency of 2.45 GHz and the average current of 100 mA. A special operation mode of the acceleration is provided for duty cycle decreasing by 100-300 times and the amplitude of current pulses 1-10 A. Two operation regimes of the FEL are possible. At the standard undulator parameters (length and number of periods are 2.5 cm and 100, B=5 kG, undulator factor is K=0.5-1, optical length is 3-5 m) positive gain in the single-particle regime is realised in the 5-170 mkm band. Low emittance permits to provide the collective amplification regime of FEL with channelling radiation. In this case the positive gain may be achieved in the wavelength region of /spl lambda/s< 1 mkm.

Study of the possibility of the production and separation of the 18F radioisotope at electron accelerators

The possibility of production and separation of the 18F medical radioisotope at a race-track microtron with an accelerated electron energy of 55 MeV in the 23Na(γ, αn) photonuclear reaction is studied. Ion-exchange chromatography is used to separate 18F from irradiated NaOH targets.

The quadrupole lens and extraction magnets of a compact race-track microtron

The compact race-track microtron (RTM) with a maximum energy of 12 MeV that is under construction at the Technical University of Catalonia consists of a quadrupole lens for horizontal focusing of the beam and four dipole magnets for the extraction of the beam from the accelerator. The source of the magnetic field in the magnets is a rare-earth permanent magnet (REPM). The main characteristics of the quadrupole lens and the extraction magnets and the procedure for the tuning of their magnetic fields are described.