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Title: Design, development, and acceleration trials of radio-frequency quadrupole

Abstract

A deuteron radio frequency quadrupole (RFQ) accelerator has been designed, fabricated, and tested at BARC, which will be used for neutron generation. The RFQ operates at a frequency of 350 MHz and needs an inter-vane voltage of 44 kV to accelerate the deuteron beam to 400 keV within a length of 1.03 m. The error analysis shows that the offset of two opposite vanes in the same direction by 100 μm leads to a change in resonant frequency by 1.3 MHz and a significant change of fields in the quadrants (∼±40% with respect to average field). From the 3D analysis, we have observed that the unwanted dipole mode frequencies are very near to the quadrupole mode frequency which will make structure sensitive to the perturbations. In order to move the dipole modes away from the quadrupole modes, we have used the dipole stabilizer rods. The 5 wire transmission line theory was used to study the perturbative analysis of the RFQ and based on this a computer program has been written to tune the cavity to get required field distribution. Based on these studies, a 1.03 m long RFQ made of OFE copper has been fabricated and tested. Even though themore » RFQ was designed for deuteron (D{sup +}) beam, we tested it by accelerating both the proton (H{sup +}) and D{sup +} beams. The RFQ was operated in pulsed mode and accelerated both H{sup +} and D{sup +} beams to designed values of 200 and 400 keV, respectively. The measured parameters are in good agreement with the designed values validating our simulations and fabrication processes. In this paper, simulations, RF measurements, and beam commissioning results are presented.« less

Authors:
; ; ; ; ; ; ; ; ;  [1]
  1. Ion Accelerator Development Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)
Publication Date:
OSTI Identifier:
22254925
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 85; Journal Issue: 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; BARC; COMMISSIONING; COMPUTER CODES; DEUTERIUM IONS; DEUTERON BEAMS; DEUTERONS; DIPOLES; HYDROGEN IONS 1 PLUS; LENGTH; PERTURBATION THEORY; QUADRUPOLE LINACS; RADIOWAVE RADIATION

Citation Formats

Rao, S. V. L. S., E-mail: svlsrao@gmail.com, Jain, Piyush, Pande, Rajni, Roy, Shweta, Mathew, Jose V., Kumar, Rajesh, Pande, Manjiri, Krishnagopal, S., Gupta, S. K., and Singh, P. Design, development, and acceleration trials of radio-frequency quadrupole. United States: N. p., 2014. Web. doi:10.1063/1.4869337.
Rao, S. V. L. S., E-mail: svlsrao@gmail.com, Jain, Piyush, Pande, Rajni, Roy, Shweta, Mathew, Jose V., Kumar, Rajesh, Pande, Manjiri, Krishnagopal, S., Gupta, S. K., & Singh, P. Design, development, and acceleration trials of radio-frequency quadrupole. United States. doi:10.1063/1.4869337.
Rao, S. V. L. S., E-mail: svlsrao@gmail.com, Jain, Piyush, Pande, Rajni, Roy, Shweta, Mathew, Jose V., Kumar, Rajesh, Pande, Manjiri, Krishnagopal, S., Gupta, S. K., and Singh, P. Tue . "Design, development, and acceleration trials of radio-frequency quadrupole". United States. doi:10.1063/1.4869337.
@article{osti_22254925,
title = {Design, development, and acceleration trials of radio-frequency quadrupole},
author = {Rao, S. V. L. S., E-mail: svlsrao@gmail.com and Jain, Piyush and Pande, Rajni and Roy, Shweta and Mathew, Jose V. and Kumar, Rajesh and Pande, Manjiri and Krishnagopal, S. and Gupta, S. K. and Singh, P.},
abstractNote = {A deuteron radio frequency quadrupole (RFQ) accelerator has been designed, fabricated, and tested at BARC, which will be used for neutron generation. The RFQ operates at a frequency of 350 MHz and needs an inter-vane voltage of 44 kV to accelerate the deuteron beam to 400 keV within a length of 1.03 m. The error analysis shows that the offset of two opposite vanes in the same direction by 100 μm leads to a change in resonant frequency by 1.3 MHz and a significant change of fields in the quadrants (∼±40% with respect to average field). From the 3D analysis, we have observed that the unwanted dipole mode frequencies are very near to the quadrupole mode frequency which will make structure sensitive to the perturbations. In order to move the dipole modes away from the quadrupole modes, we have used the dipole stabilizer rods. The 5 wire transmission line theory was used to study the perturbative analysis of the RFQ and based on this a computer program has been written to tune the cavity to get required field distribution. Based on these studies, a 1.03 m long RFQ made of OFE copper has been fabricated and tested. Even though the RFQ was designed for deuteron (D{sup +}) beam, we tested it by accelerating both the proton (H{sup +}) and D{sup +} beams. The RFQ was operated in pulsed mode and accelerated both H{sup +} and D{sup +} beams to designed values of 200 and 400 keV, respectively. The measured parameters are in good agreement with the designed values validating our simulations and fabrication processes. In this paper, simulations, RF measurements, and beam commissioning results are presented.},
doi = {10.1063/1.4869337},
journal = {Review of Scientific Instruments},
number = 4,
volume = 85,
place = {United States},
year = {Tue Apr 15 00:00:00 EDT 2014},
month = {Tue Apr 15 00:00:00 EDT 2014}
}
  • A four-rod type heavy-ion radio frequency quadrupole (RFQ) linac has been designed, constructed, and tested for the rare ion beam (RIB) facility project at VECC. Designed for cw operation, this RFQ is the first postaccelerator in the RIB beam line. It will accelerate A/q{<=}14 heavy ions coming from the ion source to the energy of around 100 keV/u for subsequent acceleration in a number of Interdigital H-Linac. Operating at a resonance frequency of 37.83 MHz, maximum intervane voltage of around 54 kV will be needed to achieve the final energy over a vane length of 3.12 m for a powermore » loss of 35 kW. In the first beam tests, transmission efficiency of about 90% was measured at the QQ focus after the RFQ for O{sup 5+} beam. In this article the design of the RFQ including the effect of vane modulation on the rf characteristics and results of beam tests will be presented.« less
  • The direct plasma injection scheme (DPIS) has been being studied at Institute of Modern Physics since several years ago. A C{sup 6+} beam with peak current of 13 mA, energy of 593 keV/u has been successfully achieved after acceleration with DPIS method. To understand the process of DPIS, some simulations have been done as follows. First, with the total current intensity and the relative yields of different charge states for carbon ions measured at the different distance from the target, the absolute current intensities and time-dependences for different charge states are scaled to the exit of the laser ion sourcemore » in the DPIS. Then with these derived values as the input parameters, the extraction of carbon beam from the laser ion source to the radio frequency quadrupole with DPIS is simulated, which is well agreed with the experiment results.« less
  • A project to study a new type of acceleration structure has been launched at Peking University, in which a traditional radio frequency quadrupole (RFQ) and a separated function radio frequency quadrupole are coupled in one cavity to accelerate the He+ beam. A helium injector for this project is developed. The injector consists of a 2.45 GHz permanent magnet electron cyclotron resonance ion source and a 1.16 m long low energy beam transport (LEBT). The commissioning of this injector was carried out and an onsite test was held in June 2013. A 14 mA He+ beam with the energy of 30more » keV has been delivered to the end of the LEBT, where a diaphragm with the diameter of 7 mm is located. The position of the diaphragm corresponds to the entrance of the RFQ electrodes. The beam emittance and fraction were measured after the 7 mm diaphragm. Its rms emittance is about 0.14 π mm mrad and the fraction of He+ is about 99%.« less