Luminosity polarization correlation in the SLC

Conference · Wed Jun 01 04:00:00 EDT 1994

OSTI ID:10194103

Decker, F J; Seeman, J T

In this paper we discuss the correlation between low luminosity and low polarization for off-energy particles in the Stanford Linear Collider (SLC). In the arcs of the SLC the spin of the polarized electrons has a net horizontal precession of about 25 turns. For example, a particle off energy by 1% deviates by 0.25 spin turns or a 90{degrees} rotation from the core. It reduces the average polarization measured by a Compton polarimeter near the interaction point (IP)Since the energy acceptance or bandwidth of the final focus optics is limited to a certain range ({approx} {plus_minus} 0.5%), these off-energy particles are not focussed as well at the IP and thus contribute less to luminosity. Therefore, the effective polarization at the IP weighted by the luminosity is higher than the measured polarization. Relative corrections of this measured value by +0.5 to 1% for the core and another +1 to 2% for low energy beam tails seems to be necessary for the 1993 run. In 1994, beam shaping with over-compression producing lower energy spreads and smaller tails together with a new arc setup with fewer effective spin turns promise to reduce this effect by an order of magnitude.

• Research Organization: Stanford Linear Accelerator Center, Menlo Park, CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC03-76SF00515
• OSTI ID: 10194103
• Report Number(s): SLAC-PUB--6562; CONF-940618--111; ON: DE95002889
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
430200
BEAM DYNAMICS, FIELD CALCULATIONS, AND ION OPTICS
BEAM LUMINOSITY
BEAM OPTICS
BEAM PROFILES
CORRELATIONS
POLARIZED BEAMS
STANFORD LINEAR COLLIDER