Algorithm of the electronic path of the TTD detector and theoretical models for the description of the modified Bragg curve

The features of the development of the electronic path of the TV channel of the television type detector (TTD) are considered. It is noted that the mode of binning (addition of pixels) is the most difficult in technical implementation. Calculations are made to improve the mathematical model for the computer detector television type. The parameters of the analytical formula valid for proton energies from 30 to 250 MeV, based on the combination of functions of the parabolic cylinder, consistent with numerical methods and new experimental data, are determined. A list of theoretical papers describing the modified Bragg curve is given.Offers the possibility of a new approach to the description of dose field Bragg peak consisting in the application of the so-called «full experience» when the experimentally measured characteristics of the dose distribution of a system of equations in which the measured values are presented as a function of the so-called «amplitude dose field». The «amplitude dose field» are determined from the solution of this system of equations. The «amplitude dose field» depend on the z coordinates in the water phantom where, the z-axis of the beam direction and after determining the amplitudes from the system of equations described-certain amplitudes are used to quickly predict the measured characteristics of the dose distribution. The combination of the adaptive electronic pathway working independently without the participation of the operator during the experiment on the calibration of the accelerator and in determining the experimentally measured characteristics of the dose distribution, allows on-line to prepare the therapeutic accelerator «Prometheus» for a session with the patient.

COMPARISON OF MCNP AND VISIPLAN DOSE-FIELD CALCULATIONS FOR MULTILAYER SHIELDING

An important factor in calculation of quantities describing the radiation situation is the selection of a calculation code. In this article, the radiation situation for selected geometries with multilayer shields was judged. Calculations were carried out using deterministic code VISIPLAN and stochastic code MCNP5. Inter-comparison of calculations with experiment was done. The aim was to compare and evaluate the results achieved by the measurements and calculations, to analyze the methods of individual calculation codes and to discuss deviations in the results. Comparison of MCNP calculations and FH40G measurements shows that the relative deviations were ±20% for each shielding configuration. The results obtained by VISIPLAN code are strongly dependent on the selected buildup factor (BUF). However, in almost all cases, it appears that using Broder’s formula to calculate BUF for multilayer shields is a good approach to refine the calculation.