Eddy currents induced in a muon storage ring vacuum chamber due to a fast kicker
Abstract
The goal of AGS E821 is a precision measurement of the muon magnetic moment (g-2) value to 0.35 ppm. A problem with muon injection is the effect of the residual magnetic field during the measurement period due to the eddy currents in the vacuum chamber induced by the kicker pulse. The paper presents a mainly analytical look at the nature of the eddy currents as an equivalent RL circuit and describes a method to solve 2D Maxwell`s operations under pulse excitation with some quantitative estimates of the decay time constants. Analysis of the results show that the field due to eddy currents is dependent on the chamber dimensions, type of material, and duration of pulse rise, flattop and fall. The field created by the rising edge of the waveform is largely canceled by the falling edge, providing the pulse is short compared to the diffusion time of the eddy current. The simulation results agree with the theoretical analysis and confirm the residual integral field at the start of the measurement period is acceptable.
- Authors:
-
- Nanjing Univ. (China). Physics Dept.
- Brookhaven National Lab., Upton, NY (United States). AGS Dept.
- Publication Date:
- Research Org.:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Org.:
- USDOE, Washington, DC (United States)
- OSTI Identifier:
- 52875
- Report Number(s):
- BNL-61249; CONF-950512-22
ON: DE95010853; TRN: 95:011955
- DOE Contract Number:
- AC02-76CH00016
- Resource Type:
- Conference
- Resource Relation:
- Conference: 16. Institute of Electrical and Electronic Engineers (IEEE) particle accelerator conference, Dallas, TX (United States), 1-5 May 1995; Other Information: PBD: [1995]
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 43 PARTICLE ACCELERATORS; STORAGE RINGS; VACUUM SYSTEMS; EDDY CURRENTS; KICKER MAGNETS; MAXWELL EQUATIONS; TWO-DIMENSIONAL CALCULATIONS; BEAM INJECTION; MAGNETIC FIELDS; COMPUTERIZED SIMULATION
Citation Formats
Feng, W Q, and Forsyth, E B. Eddy currents induced in a muon storage ring vacuum chamber due to a fast kicker. United States: N. p., 1995.
Web.
Feng, W Q, & Forsyth, E B. Eddy currents induced in a muon storage ring vacuum chamber due to a fast kicker. United States.
Feng, W Q, and Forsyth, E B. 1995.
"Eddy currents induced in a muon storage ring vacuum chamber due to a fast kicker". United States.
@article{osti_52875,
title = {Eddy currents induced in a muon storage ring vacuum chamber due to a fast kicker},
author = {Feng, W Q and Forsyth, E B},
abstractNote = {The goal of AGS E821 is a precision measurement of the muon magnetic moment (g-2) value to 0.35 ppm. A problem with muon injection is the effect of the residual magnetic field during the measurement period due to the eddy currents in the vacuum chamber induced by the kicker pulse. The paper presents a mainly analytical look at the nature of the eddy currents as an equivalent RL circuit and describes a method to solve 2D Maxwell`s operations under pulse excitation with some quantitative estimates of the decay time constants. Analysis of the results show that the field due to eddy currents is dependent on the chamber dimensions, type of material, and duration of pulse rise, flattop and fall. The field created by the rising edge of the waveform is largely canceled by the falling edge, providing the pulse is short compared to the diffusion time of the eddy current. The simulation results agree with the theoretical analysis and confirm the residual integral field at the start of the measurement period is acceptable.},
doi = {},
url = {https://www.osti.gov/biblio/52875},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon May 01 00:00:00 EDT 1995},
month = {Mon May 01 00:00:00 EDT 1995}
}