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Title: RHIC ABORT KICKER WITH REDUCED COUPLING IMPEDANCE.

Abstract

Kicker magnets typically represent the most important contributors to the transverse impedance budget of accelerators and storage rings. Methods of reducing the impedance value of the SNS extraction kicker presently under construction and, in view of a future performance upgrade, that of the RHIC abort kicker have been thoroughly studied at this laboratory. In this paper, the investigation of a potential improvement from using ferrite different from the BNL standard CMD5005 is reported. Permeability measurements of several ferrite types have been performed. Measurements on two kicker magnets using CMD5005 and C2050 suggest that the impedance of a magnet without external resistive damping, such as the RHIC abort kicker, would benefit.

Authors:
;
Publication Date:
Research Org.:
Brookhaven National Lab., Upton, NY (US)
Sponsoring Org.:
USDOE Office of Energy Research (ER) (US)
OSTI Identifier:
798550
Report Number(s):
BNL-68953
R&D Project: AD003; KA0202011; TRN: US0204839
DOE Contract Number:
AC02-98CH10886
Resource Type:
Conference
Resource Relation:
Conference: 2002 EUROPEAN PARTICLE ACCELERATOR CONFERENCE, PARIS (FR), 06/02/2002--06/07/2002; Other Information: PBD: 2 Jun 2002
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ACCELERATORS; IMPEDANCE; BROOKHAVEN RHIC

Citation Formats

HAHN,H., and DAVINO,D. RHIC ABORT KICKER WITH REDUCED COUPLING IMPEDANCE.. United States: N. p., 2002. Web.
HAHN,H., & DAVINO,D. RHIC ABORT KICKER WITH REDUCED COUPLING IMPEDANCE.. United States.
HAHN,H., and DAVINO,D. 2002. "RHIC ABORT KICKER WITH REDUCED COUPLING IMPEDANCE.". United States. doi:. https://www.osti.gov/servlets/purl/798550.
@article{osti_798550,
title = {RHIC ABORT KICKER WITH REDUCED COUPLING IMPEDANCE.},
author = {HAHN,H. and DAVINO,D.},
abstractNote = {Kicker magnets typically represent the most important contributors to the transverse impedance budget of accelerators and storage rings. Methods of reducing the impedance value of the SNS extraction kicker presently under construction and, in view of a future performance upgrade, that of the RHIC abort kicker have been thoroughly studied at this laboratory. In this paper, the investigation of a potential improvement from using ferrite different from the BNL standard CMD5005 is reported. Permeability measurements of several ferrite types have been performed. Measurements on two kicker magnets using CMD5005 and C2050 suggest that the impedance of a magnet without external resistive damping, such as the RHIC abort kicker, would benefit.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2002,
month = 6
}

Conference:
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  • Concerns regarding possible transverse instabilities in RHIC and the SNS pointed to the need for measurements of the transverse coupling impedance of ring components. The impedance of the RHIC injection and abort kicker was measured using the conventional method based on the S{sub 21} forward transmission coefficient. A commercial 450 {Omega} twin-wire Lecher line were used and the data was interpreted via the log-formula. All measurements, were performed in test stands fully representing operational conditions including pulsed power supplies and connecting cables. The measured values for the transverse coupling impedance in kick direction and perpendicular to it are comparable inmore » magnitude, but differ from Handbook predictions.« less
  • IN THIS PAPER, RESULTS FROM IMPEDANCE MEASUREMENTS ON THE RHIC INJECTION KICKERS ARE REPORTED. THE KICKER IS CONFIGURED AS A ''C'' CROSS SECTION MAGNET WITH INTERLEAVED FERRITE AND HIGH-PERMITTIVITY DIELECTRIC SECTIONS TO ACHIEVE A TRAVELLING WAVE STRUCTURE. THE IMPEDANCE WAS MEASURED USING THE WIRE METHOD, AND ACCURATE RESULTS ARE OBTAINED BY INTERPRETING THE FORWARD SCATTERING COEFFICIENT VIA THE LONG-FORMULA. THE FOUR KICKERS WITH THEIR CERAMIC BEAM TUBES CONTRIBUE AT Z/N-0.22 OMEGA/RING IN THE INTERESTING FREQUENCY RANGE FROM 0.1 TO 1 BHZ, AND LESS ABOVE.
  • In this paper, results from impedance measurements on the RHIC injection kickers are reported. The kicker is configured as a {open_quotes}C{close_quotes} cross section magnet with interleaved ferrite and high-permittivity dielectric sections to achieve a travelling wave structure. The impedance was measured using the wire method in which a resistive match provides a smooth transition from the network analyzer to the reference line in the set-up. Accurate results are obtained by interpreting the forward scattering coefficient via the log-formula. The four kickers with their ceramic beam tubes contribute a Z/n = 0.22 {Omega}/ring in the interesting frequency range from 0.1 tomore » 1 GHz, and less above. At frequencies above {approximately}100 MHZ, the impedance is ferrite dominated and not affected by the kicker terminations. Below 100 MHz, the Blumlein pulser with the {approximately}75 m feeding cables is visible in the impedance but makes no significant contribution to the results. The measurements show that the kicker coupling impedance is tolerable without the need for impedance reducing measures.« less