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Persistent URL http://purl.org/net/epubs/work/49127
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Record Id 49127
Title BBU limitations for 4GLS and Arc-en-Ciel
Abstract The designs for 4GLS and Arc-en-Ciel contain an Energy Recovery Linac (ERL) and a beam current of 100mA accelerated to 550 MeV and 2 GeV respectively. This will be challenging with regards to beam stability, since the interaction with the beam and any Higher Order Modes (HOMs) contained within the cavity could lead to the beam being lost, due to the collective effect known as Beam Break-Up (BBU). This report will discuss the linac quadrupole focusing schemes for both machines, which for one pass are similar. It will also look at the two-pass case required for 2GeV operation at Arc-en-Ciel. Further refinement of these focusing schemes will be discussed and for a multi-cavity system we will show the values of R22 and R44 must be considered in addition to the R12 and R34 given by the single cavity equation. The energy of the beam injected into the ERL linac will be shown to be an important factor in increasing the threshold, and a we will present a seven-cell cavity design that increases the peak BBU threshold current by 50%. The requirement of 100 mA BBU threshold current for both Arc-en-Ciel and 4GLS has been met; However, this is for a small parameter space, and future work detailing how this parameter space may be increased is discussed.
Organisation CCLRC , ASTeC , ASTeC-AP , CI
Keywords Physics , EUROFEL
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Language English (EN)
Type Details URI(s) Local file(s) Year
Report European FEL Design Study 2007-DS2-088. 2007. D2.9_EUROFEL-Report-2007-DS2-088.pdf 2007
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