The upcoming experiments on heating targets using intense beams of heavy ions to be carried out within the scope of the FAIR (Facility for Antiproton and Ion Research) project require measuring the ...profile of the beam on the target to estimate the optimal energy uptake by materials exposed and to interpret accurately experimental results. We propose a method to diagnose the transverse distribution of intensity of ions through registering X-rays generated by the target as a result of the incident ion beam. The numerical code Geant4 is used to develop and design a full-scale experimental model to proceed with simulating X-ray diagnostics of the ion beam. The UNILAC accelerator (GSI, Germany) is used to validate the method proposed and compare it with the results of simulation. An Au
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ion beam (energy of 11.4 MeV/a.m.u.) is passed through a copper target 10 μm thick. The X-ray image of the target is formed on a CsI scintillator using a pinhole camera. The image is recorded using a digital sCMOS camera having a brightness amplifier.
In accelerator physics, the method of absorption filters is used for measurements of the energy spectrum of electrons with energy above 100 keV. In this paper, we present a modification of the method ...to measure the delta-like spectrum of electron beams based on fitting by statistical distributions the initial experimental data and the results of simulation of the beam transmission through the filters. The method developed is much more accurate and stable than the original one and is consistent with the direct measurements by a magnetic spectrometer.
A technique for measuring the spatial heterogeneity of the light yield of a proton radiography scintillator has been developed. It is based on the recording of digital images formed during the ...passage of a proton beam through a scintillator and the approximation of the intensity distribution in the beam cross section by a two-dimensional Gaussian-like function. The results of the spatial calibration of the light yield of a lutetium silicate scintillator obtained using a magneto-optical proton microscope PUMA are presented. It is shown that accounting of the spatial heterogeneity of the scintillator makes it possible to describe the transverse beam intensity at each point of the proton radiographic image with a mean accuracy of about 0.7%. Experimental data on fluctuations in the position of the beam center, its size, and shape in the scintillator plane of PUMA microscope were obtained. The proposed technique eliminates optical artifacts in the radiographic image caused by operation of the optical recording system and artifacts caused by the electron-optical shutter, provided that the signal is proportional to the intensity of the beam. It also eliminates or strongly suppresses optical artifacts in radiographic images due to changes in the efficiency of a charge-coupled digital camera.
Information about charged particles emitted by plasma of high-current discharges is of interest both from the point of view of understanding the fundamental processes occurring in pulsed plasma and ...for applied problems. Compact magnetic spectrometers based on permanent magnets make it possible to measure the flux of charged particles from a plasma under conditions of strong electromagnetic noise. Imaging plates (IP) are one of the most commonly used types of detectors for detecting charged particles in laser-plasma and electric-discharge experiments. This paper presents the results of calibration of the BAS-MS IP when detecting electrons and the BAS-TR IP when detecting helium and tungsten ions. Calibration dependences of the sensitivity of the BAS-MS IP for electrons in the energy range of 0.65–50 MeV and the sensitivity of the BAS-TR IP for tungsten ions in the energy range from 20 eV to 650 keV are obtained, taking into account the angles of incidence of particles on the detector.
A digital model of a grazing-incidence X-ray spectrograph and methods for reconstruction of soft X-ray spectra of a Z-pinch plasma at the Angara-5-1 facility in the 2–40 nm range have been developed. ...The main problems hindering reliable qualitative and quantitative reconstruction of the initial Z-pinch X-ray spectra are the superposition of signals from different diffraction orders and the complex form of the device instrumental function. Two techniques for reconstructing the spectrum are presented. In the first one, a digital model of the spectrograph was developed in the Geant4 Monte Carlo simulation toolkit, taking into account the geometry of the experiment and the processes of interaction of X-ray radiation with a diffraction grating. In this model, taking into account the specific shape of the groove profile of the diffraction grating and the differential method for solving the diffraction problem, the X-ray intensity distribution in different diffraction orders depending on the wavelength is calculated. Using the developed model of the spectrograph, its instrumental function was calculated. The second technique does not use a specific grating groove shape, but, based on the analysis of calibration spectrograms, it constructs a dispersion relation and allows one to reconstruct the spectrum. At the end of the work, the results of reconstruction by the first and second techniques are compared and fairly good agreement between the spectra obtained by different techniques is shown.
The interaction of a heavy-ion beam with matter is a fundamental problem of plasma physics and high-energy density in matter physics. The paper presents the results of experimental studies of energy ...losses of Fe
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ions with an energy of 100 keV/u in a hydrogen plasma. The experimental data of plasma free electron stopping power are compared with theoretical models.
The article describes possible experiments with explosively driven non-ideal plasma at the proton microscope at the Facility for Antiprotons and Ion Research. It is proposed to employ linear ...explosive tubes for plasma generation and to measure an areal density in shock-compressed plasma of argon and xenon. The proposed experiments will provide valuable information on influence of strong interparticle interactions on thermodynamic properties of strongly coupled plasma. The density measurement will help the researchers to understand the nature of wall and wire precursors arising in the shock tubes.
A method for reconstruction of the volume density distribution in dynamic targets from their proton radiography image is considered. The reconstruction can be carried out using the inverse Abel ...transform under the assumption that the studied object and processes have radial symmetry. To increase the accuracy of reconstructed data, algorithms for correction of basic types of distortions of proton radiography images are proposed. The results of processing experimental data obtained on proton radiography facilities PUMA at ITEP and PRIOR at GSI are presented.
In the PANDA experiment of the FAIR project, it is proposed to use internal targets based on the hydrogen isotopes that provide a monodisperse regime of flow generation of solid spherical pellets ...with the diameter from 15–40 µm with the frequency from several tens of to several hundred kilohertz. The process for generating the pellets in such facilities includes the cooling, liquefying, and disintegration into drops of the liquid hydrogen jet directed vertically downwards; freezing of the jet when expiring with acceleration into vacuum; and its transport through the vacuum path into the region of interaction with the antiproton beam. For the effective control of the systems of the setup and for the adjustment of generation of pellets, an automatization and control system is developed combining the devices for measurement and control of pellet parameters (temperature, pressure, hydrogen flow, and piezoelectric generator frequency) and the optical diagnostics in a unified computational network. For data exchange between the devices, the TCP/IP Sockets and Modbus TCP protocols are used.
We study the gas discharge process under conditions when a relativistic electron beam is injected into the discharge tube after applying a high-voltage pulse. As a result, a plasma channel is ...created, a breakdown occurs, and a discharge develops. Comparative experiments were performed at different gas pressures under discharge conditions with and without electron beam initiation. They showed significant differences, especially during pinching and further development of the discharge.
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