Trimming Longitudinal Emittance of Au⁷⁷⁺ in the AGS

Technical Report · Fri Jan 28 04:00:00 EST 1994

DOI:https://doi.org/10.2172/1132390· OSTI ID:1132390

Brennan, M. J. ^[1]; Deng, D-P. ^[1]; Rose, J. ^[1]

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1. Brookhaven National Laboratory (BNL), Upton, NY (United States)

In FY93 gold run for SEB in AGS, the injected bunched beam from Booster was debunched into a ribbon beam and then adiabatically captured into 12 bunches. In this report, we studied a method—bucket squeezing—to trim the longitudinal emittance during the acceleration cycle in at the expense of reduced beam intensity. Longitudinal emittance is usually defined by the macroscopic area occupied by 95% of the particles in the longitudinal space. One pair of commonly used cannonical variables in the longitudinal space are the rf phase $$\phi$$ and W = (E — E_s)/wrf the energy difference from the synchronous energy divided by the angular rf frequency. Thus the longitudinal emittance takes the unit of the product of energy (electron volts) and time (seconds) or eV s. For heavy ions, a convenient unit is electron-volt-second per nucleon or eV s/u, the total emittance divided by the total number of nucleons. The longitudinal emittance is a conserved quantity under adiabatic and no beam loss conditions. Any non-adiabatic changes, such as transition crossing, can only increase the emittance. In this report, we use the bunch size, bunch area and longitudinal emittance interchangeably.

• Research Organization: Brookhaven National Laboratory (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1132390
• Report Number(s): BNL--104184-2014-IR; AGS-311
• Country of Publication: United States
• Language: English

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