scholarly journals The Evaluation of the Residual Dose Caused by the Large-Angle Foil Scattering Beam Loss for the High Intensity Beam Operation in the J-PARC RCS

Author(s):  
Shinichi Kato ◽  
Kazami Yamamoto ◽  
Hiroyuki Harada ◽  
Hideaki Hotchi ◽  
Pranab K. Saha ◽  
...  
Keyword(s):  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
D. Y. Yin ◽  
J. Liu ◽  
G. D. Shen ◽  
H. Du ◽  
J. C. Yang ◽  
...  

To accelerate high-intensity heavy-ion beams to high energy in the booster ring (BRing) at the High-Intensity Heavy-Ion Accelerator Facility (HIAF) project, we take the typical reference particle 238U35+, which can be accelerated from an injection energy of 17 MeV/u to the maximal extraction energy of 830 MeV/u, as an example to study the basic processes of longitudinal beam dynamics, including beam capture, acceleration, and bunch merging. The voltage amplitude, the synchronous phase, and the frequency program of the RF system during the operational cycle were given, and the beam properties such as bunch length, momentum spread, longitudinal beam emittance, and beam loss were derived, firstly. Then, the beam properties under different voltage amplitude and synchronous phase errors were also studied, and the results were compared with the cases without any errors. Next, the beam properties with the injection energy fluctuation were also studied. The tolerances of the RF errors and injection energy fluctuation were dictated based on the CISP simulations. Finally, the effect of space charge at the low injection energy with different beam intensities on longitudinal emittance and beam loss was evaluated.


Author(s):  
Bruce C. Brown ◽  
Philip Adamson ◽  
David Capista ◽  
Weiren Chou ◽  
Ioanis Kourbanis ◽  
...  

2014 ◽  
Vol 32 (4) ◽  
pp. 639-649 ◽  
Author(s):  
P.A.P. Nghiem ◽  
N. Chauvin ◽  
M. Comunian ◽  
C. Oliver ◽  
W. Simeoni ◽  
...  

AbstractFor very high intensity accelerators, not only beam power but also space charge is a concern. Both aspects should be taken into consideration for any analysis of accelerators aiming at comparing their performances and pointing out the challenging sections. As high beam power is an issue from the lowest energy, careful and exhaustive beam loss predictions have to be done. High space charge implies lattice compactness making the implementation of beam diagnostics very problematic, so a clear strategy for beam diagnostic has to be defined. Beam halo is no longer negligible. Its dynamics is different from that of the core and plays a significant role in the particle loss process. Therefore, beam optimization must take the halo into account and beam characterization must be able to describe the halo part in addition to the core one. This paper presents the advanced concepts and methods for beam analysis, beam loss prediction, beam optimization, beam diagnostic, and beam characterization especially dedicated to very high intensity accelerators. Examples of application of these concepts are given in the case of the IFMIF accelerators.


Author(s):  
Shinichi Kato ◽  
Kazami Yamamoto ◽  
Masahiro Yoshimoto ◽  
Hiroyuki Harada ◽  
Michikazu Kinsho

Author(s):  
George Christov ◽  
Bolivar J. Lloyd

A new high intensity grid cap has been designed for the RCA-EMU-3 electron microscope. Various parameters of the new grid cap were investigated to determine its characteristics. The increase in illumination produced provides ease of focusing on the fluorescent screen at magnifications from 1500 to 50,000 times using an accelerating voltage of 50 KV.The EMU-3 type electron gun assembly consists of a V-shaped tungsten filament for a cathode with a thin metal threaded cathode shield and an anode with a central aperture to permit the beam to course the length of the column. The cathode shield is negatively biased at a potential of several hundred volts with respect to the filament. The electron beam is formed by electrons emitted from the tip of the filament which pass through an aperture of 0.1 inch diameter in the cap and then it is accelerated by the negative high voltage through a 0.625 inch diameter aperture in the anode which is at ground potential.


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