arXiv subjects

Yu. Maltseva

Publications and source records attributed to Yu. Maltseva.

3 recordsLinked to original sources

arXiv2025

Aperture limitation localization using beam position and beam loss monitor measurements

The efficiency of beam injection in circular accelerators can be impacted by unknown aperture limitations in the vacuum chamber. These limitations can be detected by introducing localized distortions to the closed orbit of the circulating beam observed at beam position monitors (BPMs). The localized nature of introduced closed orbit distortions enables targeted identification of loss regions. In this paper, we present a method for localizing beam losses designed primarily for circular electron accelerators using a set of sequentially placed scintillator-based beam loss monitors (BLMs). By moving these monitors along the accelerator lattice, the proposed technique achieves sub-meter spatial resolution in beam loss localization. Relative calibration of the BLMs was performed using a strontium-90 radioactive source. We report experimental results from the implementation of this method at the VEPP-4M collider.

physics.acc-ph↗

arXiv2023

Coupled Twiss Parameters Estimation from Turn-by-Turn Data

Linear optics parameters are often estimated using readily available turn-by-turn (TbT) data. In-plane beta functions, which are the most common measurement objectives, can be estimated from the amplitudes or phases of TbT data, providing an overall characterization of the linear lattice. In addition to estimating uncoupled Twiss parameters, TbT data can also be utilized for characterizing coupled linear motion. We investigate several methods for constructing a full normalization matrix at each beam position monitor (BPM). BPMs provide information on beam centroid transverse coordinates, but direct observation of transverse momenta is not available. To estimate momenta, one can use a pair of BPMs or fit data obtained from several BPMs. By using both coordinates and momenta, it is possible to fit the one-turn matrix or its power at each BPM, allowing for the computation of coupled Twiss parameters. Another approach involves the minimization of peak coupling amplitudes in the spectrum of normalized complex coordinates. Similarly, the normalization matrix can be estimated by fitting linear coupled invariants. In this study, we derive and utilize a special form of the normalization matrix, which remains non-singular in the zero coupling limit. Coupled Twiss parameters can be obtained from the normalization matrix. The paper presents the results of applying and comparing these methods to both modeled and measured VEPP-4M TbT data, demonstrating effective estimation of coupled Twiss parameters.

physics.acc-ph↗

arXiv2023

Combining Methods for Localization of Linear Focusing Errors

The primary objective of accelerator tuning is to correct its linear optics. This involves adjusting a large set of parameters, such as quadrupole lens gradients and alignment errors, as well as addressing various calibration errors in beam position monitors (BPMs) and other components. These errors can significantly impact the accelerator performance. Using the full set of parameters might reduce the correction efficiency. Typically, it is advisable to prioritize the correction of large errors, as their localization can enhance the overall efficiency of the correction process. The task of error localization involves identifying the locations of potential error sources, along with their type. This paper explores and compares several commonly used error localization methods, using the SKIF model to test and evaluate their efficiency. Employing multiple methods enables cross-validation of the results obtained from the error localization process. The combined results from several localization methods improve the overall accuracy of error localization.

physics.acc-ph↗