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RUPAC-2018 26th Russian Particle Accelerator Conference |
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Influence of Mechanical
Vibrations on the Phase Resolution of Bunch Shape Monitor. |
D.A. Chermoshentsev |
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Bunch Shape Monitor with three
changeable deflectors was designed and manufactured for UNILAC, CW LINAC and
proton linac of GSI-FAIR project. The length of BSM
RF-deflector for UNILAC was large, that increased the influence of external
mechanical vibrations on the BSM operation. The model for
mechanical and electrical analysis of BSM RF-deflector and design solutions
for vibration damping are presented. |
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Luminescent Diagnostics for Low Intensity Proton
Beams at INR RAS Linac. |
A.I. Titov |
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INR RAS
linear accelerator is a high-intensity accelerator, mostly used for rare
isotopes production and neutron experiments. However low-intensity beam
research is also presented at INR linac and
requires appropriate diagnostics, such as luminescent diagnostics, which is
implemented at a new proton irradiation facility. Important experimental
results of beam position, size and intensity measurements during accelerator
run are discussed |
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Multianode Gas Counter for Low Intensity Beam Diagnostics at
the INR Linac. |
A.A. Melnikov |
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Multianode gas counter is used to measure
beam intensity in ionization mode and profiles in proportional mode at a new
INR RAS proton irradiation facility. A special model is created in COMSOL to
simulate operational characteristics of this counter. A program for data
acquisition and processing is based on LabVIEW.
Operational characteristics of the counter and experimental results of beam
measurements are presented. Upgrade of the existing software and hardware is discussed. |
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Proton Irradiation Facility
at INR RAS Linac. |
V.Serov, O.Volodkevich, S.Lebedev, A.Melnikov, A.Titov, , D. Arbuznikov, O.Podgornaya, E.Prokhorov, S. Razinkov, P.Tsedrik, S.Tsibryaev. |
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A new proton irradiation facility
to study radiation effects in electronics and different materials was
constructed at INR RAS linac. The beam intensity
range is 107÷1012 protons per separate pulses up
to 1μA of
average beam current. The energy is adjusted by switching on/off the fields in
accelerating cavities and with energy degraders in the range 20÷210 MeV.
Features of the facility development, in-air operation, diagnostics system,
as well as experimental results of beam adjustment and test irradiation are
presented. |
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Construction and RF Test of the Debuncher
for NICA Light Ion Beam Line. |
D.A. Zavadtsev |
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Debuncher
is to be installed in the present beam line after the LU-20 linac in the light ion injector of the NICA facility. The
purpose of the debuncher is to reduce by a factor
of up to ten the ion energy spread in the accelerated beam before injection
into the Nuclotron. Relative ion speed is 0.1.
Split-ring cavity driven from solid state RF amplifier at 145.25 MHz, should provide effective RF voltage up to 200 kV at 4
kW peak RF power. The RF controller allows adjust effective RF voltage for
different ions: 58 kV for Z/A=1, 121 kV for Z/A=0.5 and 190 kV for Z/A=0.3.
The debuncher cavity is provided with the stepper-motordriven capacitance tuner with 2 MHz tuning range. |
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Evaluations of Parameters Stability of S-Band RF Gun
Cavity Due to Effects of Pulsed RF Heating. |
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Requirements to high stability of
electron beam arrival time in modern FEL facilities transform to requirements
of high stability of amplitude and phase of electric field in RF photocathode
gun which is used as electron injector. To provide high quality of bunches,
gun cavities with high electricand hence magnetic
RF fields. Effects, related to pulse RF heating, result in change of the
cavity frequency and quality factor during even few μs RF pulse. Cavity deformations
due to pulse heating are considered and corresponding cavity detuning are evaluated. Resulting deviations of the phase and
amplitude of the RF field in the gun cavity as a function of RF pulse
duration are estimated. |
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Study of the Non-Uniform
Coupled System Model of CDS Section and Waveguide Segment Based on Multimode
Approximation |
I.V. Rybakov |
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With the
development of the new CDS cavity for the first four-section cavity of the
main part of INR RAS linac replacement application
of the bridge devices, similar to existing rectangular waveguide
segments-based devices, is supposed. Numerical simulation of a complete
cavity coupled with bridge devices requires unattainable computing resources.
For this reason, the analytical representation for the coupled non-uniform
system based on multimode approximation is considered. The analytical model
for a system consisting of a short CDS section coupled with a rectangular
waveguide segment is presented. The model is calibrated by direct numerical
simulation. A generalization allowing parameters selection for the new CDS
cavity sections and bridge devices coupling based on the presented model is
proposed. |
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Start of Operation of a
Standing Wave Deflecting Cavity With the Minimized Level of Aberrations |
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A family
of deflecting structures with improved RF efficiency and minimized level of
aberrations in the deflecting field distribution was presented at RuPAC 2016 [1]. The first cavity proposed in that paper
has been designed for the diagnostics of the longitudinal distribution of the
unique bunches generated at the REGAE facility. A short deflecting cavity was
constructed, tuned and is now installed in the REGAE beam line. The cavity
has been tested at the operational level of RF power. We describe main distinctive
features of the cavity and report first results on beam operation. |
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Low Energy
"Pepper-Pot" Emittance Measuring Device |
V.S. Klenov |
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The
device which includes the "pepper-pot" mask, the quartz screen, and
the CCD camera was used for measure the transverse emittances
of beam at the exit of H-minus ion source for 7-15 keV
beam energy. Emittance measuring at such low ions
energy required low-level signals from quartz screen to be recorded and
processed, while the intense glow of the gas discharge plasma created a
spurious illumination of the quartz screen. The issues of obtaining
sufficient signal level at such low ions energy, methods of subtracting the
signal of non-ion-beam illumination of quartz screen from the full amplitude
of the signal as well as issues of data processing and presentation of phase
portraits are discussed. |
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