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Title: Transvers Impedance Measurements of the Modified DARHT-2Accelerator Cell Design

Abstract

The DARHT-2 accelerator cells have been redesigned to make their high voltage performance more robust. At the outset of the DARHT-2 development program about 8 years ago, an extensive campaign was mounted to minimize the transverse impedance of the original cell design. Since the initial spec on the machine was a beam current of 4 kA, the control of beam-breakup (BBU) amplification with a 2 microsecond pulse length was considered to be one the most critical issues in the design. Even after advances in detector technology allowed the beam current requirement to be lowered to 2 kA, the goal for the standard cell impedance was kept at {approx}300 ohms/meter to allow for the possibility of future beam current upgrades to 4 kA without any modifications in the cells. The results of this campaign to minimize the transverse impedance are described in detail in Reference 1. After several iterations in the design of ferrite dampers and the anode finger stock shape, the measured (peak) impedance of the original standard cell was determined to be about 280 ohms/meter. (As a reference point, the measured impedance of the DARHT-1 cell is about 880 ohms/meter). This impedance provided such a wide safety margin againstmore » BBU amplification at 2 kA that it was felt that the cell redesign could focus on voltage holding without any detailed considerations of impacts on the transverse impedance. Now that a baseline design for the DARHT-2 cell has been established and tested, however, it was felt that a measurement of its impedance would be prudent. The results of these impedance measurements are presented in this note. The objective was mainly to do a ''quick check'' to ensure that there were no surprises, and to provide an estimate of the BBU frequencies and growth rates to the experimental test program.« less

Authors:
;
Publication Date:
Research Org.:
Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
Sponsoring Org.:
USDOE Director. Office of Science. Office of Fusion EnergySciences
OSTI Identifier:
889900
Report Number(s):
LBNL-59199; HIFAN 1428
R&D Project: Z41003; BnR: AT5015031; TRN: US0604505
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; 43 PARTICLE ACCELERATORS; ACCELERATORS; AMPLIFICATION; ANODES; BEAM CURRENTS; DESIGN; FERRITE; FINGERS; IMPEDANCE; MODIFICATIONS; PERFORMANCE; SAFETY; SHAPE

Citation Formats

Briggs, Dick, and Waldron, Will. Transvers Impedance Measurements of the Modified DARHT-2Accelerator Cell Design. United States: N. p., 2005. Web. doi:10.2172/889900.
Briggs, Dick, & Waldron, Will. Transvers Impedance Measurements of the Modified DARHT-2Accelerator Cell Design. United States. doi:10.2172/889900.
Briggs, Dick, and Waldron, Will. Wed . "Transvers Impedance Measurements of the Modified DARHT-2Accelerator Cell Design". United States. doi:10.2172/889900. https://www.osti.gov/servlets/purl/889900.
@article{osti_889900,
title = {Transvers Impedance Measurements of the Modified DARHT-2Accelerator Cell Design},
author = {Briggs, Dick and Waldron, Will},
abstractNote = {The DARHT-2 accelerator cells have been redesigned to make their high voltage performance more robust. At the outset of the DARHT-2 development program about 8 years ago, an extensive campaign was mounted to minimize the transverse impedance of the original cell design. Since the initial spec on the machine was a beam current of 4 kA, the control of beam-breakup (BBU) amplification with a 2 microsecond pulse length was considered to be one the most critical issues in the design. Even after advances in detector technology allowed the beam current requirement to be lowered to 2 kA, the goal for the standard cell impedance was kept at {approx}300 ohms/meter to allow for the possibility of future beam current upgrades to 4 kA without any modifications in the cells. The results of this campaign to minimize the transverse impedance are described in detail in Reference 1. After several iterations in the design of ferrite dampers and the anode finger stock shape, the measured (peak) impedance of the original standard cell was determined to be about 280 ohms/meter. (As a reference point, the measured impedance of the DARHT-1 cell is about 880 ohms/meter). This impedance provided such a wide safety margin against BBU amplification at 2 kA that it was felt that the cell redesign could focus on voltage holding without any detailed considerations of impacts on the transverse impedance. Now that a baseline design for the DARHT-2 cell has been established and tested, however, it was felt that a measurement of its impedance would be prudent. The results of these impedance measurements are presented in this note. The objective was mainly to do a ''quick check'' to ensure that there were no surprises, and to provide an estimate of the BBU frequencies and growth rates to the experimental test program.},
doi = {10.2172/889900},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2005},
month = {11}
}