Design of STRAUS-R accelerator

The paper presents a design of the direct-operation high-current electron accelerator STRAUS-R that is a modification of STRAUS-2 now in force. The accelerator is aimed at generating single bremsstrahlung pulses in the mode of electron beam focusing on the target. According to the calculations it should provide for getting the dose (Si) of 0.2÷0.25 Gy at a 1 meter distance from the target, the electron beam current being equal to 50÷60 kA, boundary energy of electrons – to 2.7÷3.0 MeV, bremsstrahlung pulse duration – to ≤ 50 ns and beam diameter on the target – to ≤ 5 mm. The description and results of numerical simulation of physics processes taking place in the accelerator are given

Numerical simulation of the processes of small-diameter high-current electron beam shaping and injection

With the aid of BEAM25 program there was carried out the numerical simulation of the non-stationary process of shaping a small-diameter (≤ 20 mm) high-current hollow electron beam in a diode with magnetic insulation, as well as of the process of beam injection into the accelerating LIA track. The diode configuration for the purpose of eliminating the leakage of electron flux to the anode surface was updated. Presented are the results of calculation of the injected beam characteristics (amplitude-time parameters of a current pulse, space-angle distributions of electrons etc.) depending on diode geometric parameters

RADIATION METHOD OF TEMPERATURE MEASURMENT IN THE ZONE OF LOCALIZED IMPACT LOADING

The radiation low-inertial method was developed for temperature measurment in the impact contact zone, using the pyrometer based on the non-cooled photoresistor and flexible fibre-optical cable. The pyrometer is attached to the "pneumatic gun" testing rig, which provides the collision of steel balls having the diameters up to 3 x 10-3 m and other hard particles with the specimen surface at the velocities up to 300 m/sec. The impact angles vary continiously from 0 to 90°. This method allows to measure the temperatures in the impact zone of the materials with low and high electroconductivity and is advantageous in comparison with methode using thermocouples of different types. The experimental data are obtained for some technically pure metals and structural steels at various impact energies and angles. They show the experimental possibilities of this method and have their own scientific value

Intramolecular vibrational dynamics of ν

Intramolecular dynamics of the vibrational levels (up to v = 5) of the ν1 mode in (CF3)2CCO molecule, induced via multiphoton selective excitation of this mode by resonant femtosecond IR radiation, was studied. The times of intramolecular vibrational energy redistribution (IVR) of each vibrational level v to the remaining modes of the molecule were measured. In accordance with the theory predictions the decrease of IVR time with increasing v is observed. A sharp reduction of the IVR time (up to 1 ps) at a wavelength of 2130 cm−1 of transition v=3 → v=4 was found. It was shown that with a negative chirp of a femtosecond radiation pulse the population of high-lying vibrational levels of ν1 modes significantly increases

Intramolecular vibrational dynamics of ν1 mode in (CF3)2C=C=O molecule induced by resonant IR femtosecond radiation

Intramolecular dynamics of the vibrational levels (up to v = 5) of the ν1 mode in (CF3)2CCO molecule, induced via multiphoton selective excitation of this mode by resonant femtosecond IR radiation, was studied. The times of intramolecular vibrational energy redistribution (IVR) of each vibrational level v to the remaining modes of the molecule were measured. In accordance with the theory predictions the decrease of IVR time with increasing v is observed. A sharp reduction of the IVR time (up to 1 ps) at a wavelength of 2130 cm−1 of transition v=3 → v=4 was found. It was shown that with a negative chirp of a femtosecond radiation pulse the population of high-lying vibrational levels of ν1 modes significantly increases

Intramolecular vibrational dynamics of ν 1

Intramolecular dynamics of the vibrational levels (up to v = 5) of the ν1 mode in (CF3)2CCO molecule, induced via multiphoton selective excitation of this mode by resonant femtosecond IR radiation, was studied. The times of intramolecular vibrational energy redistribution (IVR) of each vibrational level v to the remaining modes of the molecule were measured. In accordance with the theory predictions the decrease of IVR time with increasing v is observed. A sharp reduction of the IVR time (up to 1 ps) at a wavelength of 2130 cm−1 of transition v=3 → v=4 was found. It was shown that with a negative chirp of a femtosecond radiation pulse the population of high-lying vibrational levels of ν1 modes significantly increases

Facility for Neutron Multiplicity Measurements in Fission.

Abstract not availableJRC.D-Institute for Reference Materials and Measurements (Geel