Ultrafast electron microbunch trains have broad applications in which the individual bunch length and the bunch-to-bunch interval are critical parameters that need to be precisely diagnosed. However, ...directly measuring these parameters remains challenging. This paper presents an all-optical method that simultaneously measures the individual bunch length and the bunch-to-bunch spacing through an orthogonal THz-driven streak camera. For a 3 MeV electron bunch train, the simulation indicates that the temporal resolution of individual bunch length and the bunch-to-bunch spacing is 2.5 fs and 1 fs, respectively. Through this method, we expect to open a new chapter in the temporal diagnostic of electron bunch trains.
In this paper, we describe the project of a photon source with energies up to 2500 MeV at the SKIF synchrotron radiation facility (under construction in Novosibirsk). It is intended for experiments ...on photonuclear reactions, nonlinear QED, EM detector calibration and other applications. A polarized photon beam with a flux of 10
6
–10
8
Hz (in full spectrum) is produced using Compton backscattering (or inverse scattering) of IR, visible, and UV laser radiation, as well as the UV band of its own synchrotron radiation, on the SKIF electron beam (15 kHz). Spectrum monochromatization with collimators or/and tagging system by recoil electrons is possible. The discrepancy between experimental and theoretical photofission cross sections of actinide nuclei in a photon energy range of hundreds of MeV has been known since the 1980s, so it is proposed to study these cross sections in the first series of experiments.
—In this paper, the influence of the effects of potential well distortion and longitudinal microwave instability on the longitudinal size of the electron beam in the VEPP-4M collider is considered. ...As a result, the value of the longitudinal broadband impedance was obtained, which can be used to calculate the longitudinal size of the beam in any collider mode.
This work is devoted to the development of a method for measuring beam sizes in cyclic charged particle accelerators using an interferometer based on the Young scheme with a double-slit diaphragm. We ...have carried out an experimental verification of the original spectral method for scanning the interference pattern. The results of measurements of the spectrum of low-frequency oscillations of the beam of the storage ring of the Kurchatov Synchrotron Radiation Source (KSRS) obtained by means of the Optical Observation Station (OOS) of the storage ring are presented.
The results of a study of outgassing of boron carbide and durable ultrahigh molecular weight polymethyl methacrylate (organic glass) in vacuum are presented. It is shown that boron carbide ...manufactured by OOO Virial (St. Petersburg) by the cold-pressing technique, which is followed by free sintering at a temperature of approximately 2200°C, meets the requirements that are stated by the ITER (International Thermonuclear Experimental Reactor). The results studying ultrahigh molecular weight durable polymethyl methacrylate (UMW-PMMA), which was manufactured at the Institute of Solid-State Chemistry and Mechanochemistry, Siberian Branch, Russian Academy of Sciences (ISSCM SB RAS) using original technologies, showed that UMW-PMMA with frontal polymerization has the lowest gas emission compared to “conventional” PMMA and is very promising for the manufacture of specialized vacuum chambers for electrophysical facilities.
This paper describes stations, both existing and under development, for the diagnostics of beam parameters of the 3rd stage of the Novosibirsk free electron laser (FEL). A modification of the method ...for measuring electron energy spread using the spectrum of spontaneous undulator radiation under the operating conditions of the Novosibirsk FEL is presented.
The aim of the study was to evaluate the clinical manifestations and survival of patients with giant cell arteritis (GCA).
Materials and methods
.
A retrospective study included 166 patients with ...newly diagnosed GCA. Clinical, laboratory, and instrumental data and three sets of classification criteria were used to confirm the diagnosis: the American College of Rheumatology (ACR) 1990, the revised ACR criteria of 2016 and/or the new ACR and European Alliance of Rheumatologic Associations (EULAR) 2022 criteria. Some of the patients underwent instrumental investigations: temporal artery ultrasound Doppler (
n
= 61), contrast-enhanced computed tomography (
n
= 5), CT angiography (
n
= 6), magnetic resonance imaging (
n
= 4), MR angiography (
n
= 3), and 18F-FDG PET/CT (
n
= 47). Overall and recurrence-free survival rates were analyzed using survival tables and Kaplan–Meier method.
Results
.
The most frequent first manifestations of GCA were headache (81.8%), weakness (64%), fever (63.8%), and symptoms of rheumatic polymyalgia (56.6%). Changes in temporal arteries in color duplex scanning were detected in 44 out of 61 patients. GCs therapy was performed in all patients who agreed to be treated (
n
= 158), methotrexate was used in 49 out of 158 patients, leflunomide in 9 patients. In 45 (28.5%) out of 158 patients, a stable remission was achieved as a result of GC monotherapy; in 120 (75.9%) patients, long-term maintenance therapy with GCs was required to prevent exacerbations, including 71 (44.9%) patients in combination with methotrexate or other immunosuppressive drugs. The follow-up period of patients with a history of relapses was 21.0 (8.0–54.0) months. Relapses developed in 73 (46.2%) patients. The overall one-year survival rate was 97.1% 95% CI 94.3; 99.9, and the five-year survival rate of patients was 94.6% 95% CI 90.2; 99.0. The one-year relapse-free survival rate was 86.4% 95% CI 80.5; 92.3, and the five-year relapse-free survival rate was 52.4% 95% CI 42.0; 62.8. Twelve (7.2%) of 166 patients died. The cause of death was myocardial infarction in two patients, stroke in two patients, and breast cancer in one patient; in the remaining seven cases, the cause of death was not determined.
Conclusions.
Given the high frequency of disease exacerbation, patients with GCA require long-term follow-up, especially during the first year after diagnosis.
The energy recovery linear accelerator of the Novosibirsk Free Electron Laser facility can be used as a source of short X-ray pulses. Bremsstrahlung is produced by the electron current of the ...accelerator passing through a thin foil with a bunch repetition frequency of several megahertz and a picosecond duration of an individual bunch. This article discusses the possibilities of creating such a source and the results of the first experiments.
The first stage of the linear accelerator of the Siberian Circular Photon Source (SKIF) accelerator facility has been successfully commissioned at the Budker Institute of Nuclear Physics, Siberian ...Branch, Russian Academy of Sciences (BINP). This test accelerator facility includes the radiofrequency (RF) gun, magnet system, RF accelerating structures, and diagnostic and control system elements. The aim of the work at the facility is to verify the correctness of solutions chosen for the accelerator design, as well as to get operation experience and to measure the beam parameters that will determine the successful work of the overall SKIF complex. This article describes the main subsystems of the test accelerator facility and briefly presents the first operation results concerning the beam parameters.