Instruments and Experimental Techniques最新文献

The calibration of two types of an electrostatic beam position monitor was carried out. Signals from the electrodes are converted into beam coordinates using a nonlinear polynomial transformation, the coefficients of which are calculated using the least squares method. This made it possible to measure the position of the beam with an accuracy better than the required value of 0.1 mm for a single passage of the beam. The mechanical center of the monitor has been linked to external geodetic signs. The calibration result was used with all monitors in the ring based on the assumption that they were all manufactured to the same mechanical accuracy. This made it possible to measure beam parameters with better accuracy than before calibration.

An optical scheme of the channel for transporting ¹²C⁺⁶ carbon ion beams to the radiobiological research area is presented. The results of deceleration of carbon ions in the accelerator U-70 from 455 to 200 MeV/nucleon and beam output from U-70 are presented. The scheme of uniform dose field formation by means of vertical and horizontal wobbler magnets is considered. Plans for the development of ion-beam therapy channels at the IHEP accelerator complex are given.

The project of a facility for studying the ionizing radiation effects from outer space is under development at Russian Federal Nuclear Center All-Russia Research Institute of Experimental Physics (RFNC-VNIIEF, Sarov). The National Research Center Kurchatov Institute (KCTEF) has developed a technical project and design documentation for a heavy ion linac. The linac provides the acceleration of the beams with the mass-to-charge ratio within the range of 4–8 in a pulsed mode up to energy of 4 MeV per nucleon with a current of 10 mA. The accelerator consists of a laser ion source, an RFQ section and two DTL sections operating at multiple frequencies. The world’s most powerful laser ion source can generate a Bi²⁷⁺ ion beam with a current of at least 3 mA at a pulse duration of 5 μs. In the linac, at least 95% of the injected beam current is captured in acceleration.

Information on the current state of the radio-biological stand (RBS) on a beam of carbon ions extracted from the U-70 accelerator complex is presented. The slow extraction (up to 900 ms) of a beam of carbon nuclei with energies of 200–450 MeV/nucleon from the U-70 accelerator to the RBS setup has been mastered for radiobiological and preclinical research, which are aimed at developing domestic methods for treating oncological diseases with accelerated carbon ions. The equipment for transporting the beam to the RBS zone and the devices for passive and active beam modification are briefly described, the characteristics of the beam are given, and the results of the latest modernization of the RBS are presented. The results of radiobiological studies obtained using the RBS setup are also presented.

One of the charged-particle accelerators with relatively low energy and relatively high current is the vacuum insulated tandem accelerator. The work notes the originality of the accelerator design and presents the results of the research. It was shown that replacing ceramic insulators with a smooth side surface with insulators with a corrugated outer surface ensured the required voltage of 1.15 MV without breakdowns. The required current of 10 mA was obtained by upgrading the facility, which followed the experimental determination of the effect of space charge on the transport of ions and significant suppression of the flow of secondary charged particles. The measured phase portraits of a beam of negative hydrogen ions and a beam of protons injected into the accelerator are presented. It is noted that the facility is primarily used for the development of boron-neutron capture therapy techniques for malignant tumors, for radiation testing and modification of promising materials with a neutron flux, for measuring the cross section and yield of nuclear reactions, and for other applications.

A technique for developing a fast summing preamplifier for resistive plate counters of the HARP experiment (PS214, CERN) is presented. The classic analog adder has been redesigned to obtain a minimum intrinsic jitter of 26 ps. This jitter has been attained via a trade-off with a charge summation accuracy of ~5%. The summing preamplifier has eight inputs and is based on the principle of summing a 104 × 240-mm² readout area containing eight strips with dimensions of 104 × 29 mm². The preamplifier is located inside the chamber. Its conversion factor is 100 mV/pC at a charge collection time of approximately 1 ns. The spread of the systematic timing error at the inputs is less than 30 ps. The power consumption is 350 mW. There are 368 summing amplifiers in the time-of-flight system.

The article presents the concept of gas analyzer based on Raman spectroscopy where a multimode blue diode laser is used as an excitation source. Methods for reducing the spectral width of the radiation of such a laser due to external feedback have been investigated. It has been shown that, when an optical scheme based on Fabry–Pero interferometer is used for this purpose, the resolution of the recorded Raman spectra can reach 8 cm^–1. The performance of the developed Raman gas analyzer is presented and discussed. It was established that the achieved signal-to-noise ratio at the analysis time of 2 s allows detection of any type of molecule with concentration of >1%.

To achieve timely and effective monitoring of the health status of bridge power cables, as well as to address the deficiencies in the existing monitoring system such as incomplete functional and state evaluation, we propose a multi-parameter state monitoring system based on fiber Bragg grating (FBG) sensing technology and microelectromechanical systems (MEMS) sensing technology. This system enables vibration, strain, temperature, and deformation measurements of both the bridge power cable and its expansion compensation device. In order to comprehensively evaluate the health status of the bridge power cable, we introduce a comprehensive fusion model for multi-state assessment. Furthermore, to enable real-time monitoring capabilities, we have developed a web-based monitoring system that can receive real-time sensor data and present it to users through an intuitive visual interface. Finally, by applying our proposed model to Zhoushan–Daishan Bridge in Zhoushan City as an example, we validate its feasibility and effectiveness in enhancing performance and practicality of bridge power cable monitoring systems.

Data taking has been started at the first stage of the SPASCHARM experiment on systematic study of the spin effects in strong interactions. The current setup configuration is described, and the detector characteristics attained during the beam data taking in the runs of 2018–2022 are listed.