Report/Journal Article

PUBDB-2017-06670

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Strength of higher order spin-orbit resonances

Hoffstaetter, G. H. ; Vogt, M.DESY*

2004
Inst. Woodbury, NY

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Please use a persistent id in citations: doi:10.1103/PhysRevE.70.056501  doi:10.3204/PUBDB-2017-06670

Report No.: DESY-04-154; physics/0405108

Abstract: When polarized particles are accelerated in a synchrotron, the spin precession can be periodically driven by Fourier components of the electromagnetic fields through which the particles travel. This leads to resonant perturbations when the spin-precession frequency is close to a linear combination of the orbital frequencies. When such resonance conditions are crossed, partial depolarization or spin flip can occur. The amount of polarization that survives after resonance crossing is a function of the resonance strength and the crossing speed. This function is commonly called the Froissart-Stora formula. It is very useful for predicting the amount of polarization after an acceleration cycle of a synchrotron or for computing the required speed of the acceleration cycle to maintain a required amount of polarization. However, the resonance strength could in general only be computed for first-order resonances and for synchrotron sidebands. When Siberian Snakes adjust the spin tune to be 1/2, as is required for high energy accelerators, first-order resonances do not appear and higher-order resonances become dominant. Here we will introduce the strength of a higher-order spin-orbit resonance, and also present an efficient method of computing it. Several tracking examples will show that the so computed resonance strength can indeed be used in the Froissart-Stora formula. HERA-p is used for these examples which demonstrate that our results are very relevant for existing accelerators.

Keyword(s): proton synchrotron: polarized beam ; polarization: resonance ; spin: rotator ; programming: orbit ; numerical calculations: orbit ; DESY HERA Stor

Note: M-Bereich

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Contributing Institute(s):

1. DESY Retrocat (DESY(-2012))

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

Experiment(s):

1. No specific instrument

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Database coverage:
; ; ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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