In proton therapy, depth scanning of the irradiated object is performed by changing the Output Energy (OE) of the accelerated beam. In pulsed linear accelerators, adjustment of the OE is usually by changing the amplitude and/or phase of the fi eld in the accelerating elements from one RF pulse to another. The application of non-inertial traveling wave accelerating sections makes it possible to change quickly the phase of the accelerating fi eld during the RF pulse. The phase of the fi eld in the constant gradient section is determined both by the phase of the input RF signal and by the process of wave propagation in the dispersive structure. The calculation results of the traveling wave propagation in the accelerating structure when the phase of the input RF signal changes and the results of simulation the dynamics of particles confirm the change in the linac’s OE during the RF pulse. The proposed method for regulation the OE makes it possible to increase in orders the speed of scanning the irradiated object by depth.

The main part (MP) of a compact pulsed proton linac is designed to accelerate a beam with a pulsed current reaching 2.5 mA to an output energy controlled in the range from 60 to 230 MeV while maintaining small transverse beam dimensions. The traveling wave accelerating structure is used in the S -band frequency range. It provides a high accelerating rate and allows one to adjust the output energy of the bunches within the RF pulse. Particular attention is paid to the balance and reliability of the proposed solutions, accessibility and motivated feasibility of the MP elements.

In proton therapy, depth scanning of the irradiated object is performed by changing the Output Energy (OE) of the accelerated beam. In pulsed linear accelerators, adjustment of the OE is usually by changing the amplitude and/or phase of the field in the accelerating elements from one RF pulse to another. The application of non-inertial traveling wave accelerating sections makes it possible to change quickly the phase of the accelerating field during the RF pulse. The phase of the field in the constant gradient section is determined both by the phase of the input RF signal and by the process of wave propagation in the dispersive structure. The calculation results of the traveling wave propagation in the accelerating structure when the phase of the input RF signal changes and the results of simulation the dynamics of particles confirm the change in the linac's OE during the RF pulse. The proposed method for regulation the OE makes it possible to increase in orders the speed of scanning the irradiated object by depth.

In this paper, we have considered the possibility of using a neural network for calculation the weight coefficients corresponding to the Bragg curves for forming a uniform depth dose distribution in proton therapy.

In Fig. 5 on page 341, the units for the X and Z axes should read cm. In Fig. 6 on page 341, the units for the X and Y axes should read cm.

The article presents the results of the development of electron accelerators, performed at the Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, as well as in the recently created Laboratory of Electron Accelerators MSU (LEA MSU). The report focuses on the new linear electron accelerators for radiography, cargo inspection, medicine, as well as industrial accelerators with high beam power and energy from up to 10 MeV, which are developed by LEA MSU and manufactured jointly with JSC "RPE "Toriy". Over the past year, more than 20 accelerators of six different types have been delivered to customers.

Photon activation technique using bremsstrahlug with end-point energy 55.6 MeV is used to induce photonuclear reactions in a 209Bi target. Absolute yields and integrated cross sections of multiparticle reactions (γ, 2n-6n), (γ, 4n1p), and (γ, 5n1p) are obtained. The results are compared to predictions of statistical models using systematical and microscopic description of photoabsorption and to the result of evaluation of the partial photoneutron reaction cross sections. Based on a comparison with existing experimental photoneutron cross sections and model calculations, we make a conclusion that neutron multiplicity assignment in available photoneutron cross sections on 209Bi can be corrected and evaluated cross sections of (γ, 1n) and (γ, 2n) are obtained that are in an agreement with the obtained experimental results.

The experimental setup that is used at the Skobeltsyn Institute of Nuclear Physics of the Moscow State University to study photonuclear reactions using the activation technique is described. The system is based on two modern compact race track microtrons with maximum energy of electrons of up to 55 and 67.7 MeV. A low-background HPGe detector is used to measure the induced gamma activity. The data acquisition and analysis system, used to process the measured spectra, is described. The described system is used to study multiparticle photonuclear reactions and production of nuclei far from the beta stability region.

На разрезном микротроне измерен выход радиоизотопов, образующихся в фотоядерных реакциях на естественной смеси изотопов титана при энергии электронов 55 МэВ.

The yield of radioisotopes formed during photonuclear reactions in a natural mixture of titanium isotopes is measured at an electron energy of ≈15 MeV using a slot microtrone.

A race-track microtron is used to measure the yield of 18 F in the reaction 19 F(γ, n) at an energy of the electron beam of 55 MeV. 18 F is widely used in positron emission tomography for high-sensitivity diagnostics. The currently available data are not sufficient to make accurate estimates of the yield of 18 F in isotope production experiments using the reaction (γ, n). The value of σ −1 estimated in this work is (1.7 ± 0.1) mb.

The possibility of using radioactive sources to measure atomic number Z and the amount of substance nD of unknown objects is considered. An experiment is performed with test samples of different materials exposed to γ-rays from Cs-137 and Co-60 sources. The range of the method’s applicability in measuring atomic number Z and amount of substance nD is shown.

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.