Instruments and Experimental Techniques最新文献

Determining the threshold values in case of multiple bit upsets based on impinging particles flux density is an urgent problem for radiation-hardened electronics designers. To deal with such class of problems, a special three-beam pulsed electron linac called SPRUT was developed. The linac is used to generate an electron beam with electron energy of 5–7 MeV, current of approx. 1 A, pulse width of 1–12 μs, and repetition rate up to 1 Hz. Total electron beam, not less than 20 mm in diameter, with high electron flux density is generated behind the exit foil. Configuration and position of the combined beams can be adjusted to ensure the irradiation area non-uniformity not worse than 30%. The paper describes the SPRUT linac design and operating principle, as well as the methods used to measure its characteristics and the results obtained thereby, it helps studying the possibilities to generate the radiation field with certain characteristics.

A method is considered for integral counting of the number of particles in the cross section of a homogeneous radiation beam based on measuring the number of particle tracks registered in the plane of a solid-state detector using “machine vision” technology.

An automatic frequency tuning system has been developed and implemented for probes used in nuclear magnetic resonance (NMR) and quadrupole resonance (NQR) spectroscopy. It is based on available technologies that allow for assembling this system for any probe, regardless of the control method. The control electrical part is implemented on the Arduino platform and includes platform-compatible modules: stepper motors and a servo. The equipment for placing the control system was manufactured using additive technologies, which simplified the process of prototyping and assembly a ready-made system. Due to the availability and low cost of the components, the automatic tuning system can be adapted and configured for any NMR-probes. This auto tune system made it possible to avoid manual adjustment of the probe during the experiment and reduce the time spent.

A method for stabilizing the prebreakdown state of vacuum gaps, based on the use of an anode made of a material with high specific resistance, has been proposed and implemented on an experimental stand. Traces of prebreakdown phenomena on the surface of cathodes, which usually lead to a vacuum spark and self-destruction, were identified and a preliminary study was conducted. This technique will allow for further expanding the understanding of the nature of vacuum breakdown and electroplastic phenomena in critically strong electric fields with a strength of over 1 MV/cm. It is proposed to use prebreakdown electrostatic treatment of the surface of metals and semiconductors to study the possibility of obtaining effective cold electron emitters.

A method is proposed for the results correction of the output power measurements of orotrons with two-row periodic structure (TRPS) carried out with the help of the detector graduation section in a waveguide with a cross section of 1.6 × 0.8 mm² with the detector disposition in the wide wall middle of a waveguide. The results of this method at the correction of the outputpower measurements are presented for the orotron with TRPS of the 2-mm region wavelength.

An approach to determining and describing the distribution of the longitudinal and transverse components of the magnetic field in an axisymmetric laboratory electromagnet is proposed based on a polynomial expansion of the field induction taking into account the restrictions imposed by Maxwell’s equations. It is shown that the proposed approach allows obtaining high accuracy in describing the magnetic field distribution with a small number of measurements. It may also be of interest for refining the parameters of laboratory equipment and be used as a training task in laboratory practice when studying the properties of the electromagnetic field.

Numerous devices are used in synchrotrons and storage rings to provide close-orbit continuous circulation of particle beams in pipeline of the facility. These are power supplies for the magnetic and RF systems. The high accuracy and stability of the output parameters (the output current or voltage) must be exhibited by the power supplies of the magnetic system. If it is necessary to control a facility with circulating beams (e.g., in the case of beam acceleration in a synchrotron), mutual synchronization of the performance of all devices is also required. An embedded controller with an analog interface to a controlled device is described. The relative accuracy of 100 ppm with respect to the entire operating range of the device and the possibility of mutual synchronization by external clock pulses following with a frequency as high as 10 kHz is provided by the controller. Examples of the controller application to control various devices and systems are presented.

We discuss the performance of the distributed fiber optic sensor (DFOS) interrogation unit based on the phase-optical time domain reflectometry (ϕ-OTDR) principle. This experiment focuses on improving the performance of ϕ-OTDR by controlling two selective parameters: probe power and laser pulse width. These parameters were chosen due to their significant impact on the signal-to-noise ratio (SNR), which directly influences the sensitivity and accuracy of the system. Two experiments were conducted using 10 and 40 km standard ITU-T G.652D telecom grade bare fiber optic connected to the ϕ-OTDR setup. For each experiment, two sets of probe laser parameters (launched optical power and pulse width) were varied, and the SNR was calculated as an indicator of performance. An SNR of 13.99 dB was achieved from a 10 km ϕ-OTDR setup with a pulse width of 300 ns (launched optical power fixed at 100 mW). With launched optical power fixed at 100 mW, an SNR of 12.76 dB was obtained from a 40 km ϕ-OTDR setup when the pulse width was set to 500 ns. Data analysis revealed that SNR values in both ϕ-OTDR setups (10 and 40 km) approached saturation as the probe power launched and optical power increased. This study highlights that the best signal performance can be achieved by carefully optimizing these selective parameters, as their interplay determines the balance between spatial resolution and signal strength in the ϕ-OTDR system.

The new generation neutrino telescope Baikal-GVD is under deployment in Lake Baikal. The telescope registers Cherenkov radiation resulting from the interaction of neutrinos with the water environment of the lake, using the spatial structure of optical modules – photodetectors. To determine the direction to the neutrino source, it is necessary to know the coordinates of each module at the time the event was recorded. The article describes the design and operating principle of the inertial positioning system, which serves to determine the spatial position of modules in the aquatic environment, and presents the first results of its operation.

A scheme of a charge-sensitive preamplifier (CSP) for measuring the energy and time of flight of detected particles is described. The CSP has two outputs. At the E-output, the signal is determined by the integral of the charge formed by a particle in a semiconductor detector. The signal amplitude at this output is proportional to the particle energy. At the T-output, the signal follows the shape of the detector current pulse and has a short rise time, which reduces the timing error. A circuit diagram of the CSP is shown, and calculations of the signal parameters at the E and T outputs are given. The results of modeling and the measured parameters of the proposed scheme are presented. The criterion of the expediency of using the time channel of the CSP depending on the radiation time of the radiator crystal or the charge collection time is obtained. The CSP is intended for use in photon spectrometers based on PWO crystals and avalanche photodiodes, but it can also be used in spectrometers with other types of semiconductor detectors.