Dear Colleagues, I am announcing that CCB has received a change request for the Main Linac (ML) section of ILC Baseline Config Doc from C.Adolphsen, who is representing the ML AG. This change request mainly relates to layout specifications for the cryostats, beam position monitors, focusing quads and the associated orbit correction dipole magnets. Another part of the change request relates to elimination of a duplicate subsection (cryogenics). The requesters suggest Class 0 as classification for this change request. The CCB chair tentatively agrees to treat this as Class 0, pending consultation within CCB. I am asking W.Funk and C.Pagani to act as CCB reviewers (to be confirmed shortly). Now this request is brought to review by CCB, and is also open to general discussion. Any members of GDE or GDE-related task groups with comments or questions on this request, please, direct them to ml-ccb@xxxxxxxxxxxx and/or ml-ext-gde@xxxxxxxxxxxx by the end of Friday, June 16, PDT. BCD is available at http://www.linearcollider.org/wiki/doku.php?id=bcd:bcd_home BCD change history is available at http://www.linearcollider.org/wiki/doku.php?id=bcd:bcd_history ML-related RDR materials are compiled and posted at http://www.linearcollider.org/wiki/doku.php?id=rdr:rdr_as:main_linac_home Sincerely, - Nobu Toge (KEK, Accelerator Lab) email: toge@xxxxxxxxxxxx voice: +81-29-864-5224 fax: +81-29-864-3182
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- Subject: [CCB-445] Linac Change Requests
- From: "Adolphsen, Chris" <star@xxxxxxxxxxxxxxxxx>
- Date: Sun, 11 Jun 2006 23:19:03 -0700The Main Linac section of the BCD is attached and includes changes and refinements on page 36 and page 38 (using Track Changes) for which we request approval by the Change Control Board - we believe these to be type zero. On page 36: Have one quad every three cryomodules (i.e., one per rf unit). This was the Snowmass recommendation and was stated in the BCD until Nick/Tor changed it to one in four cryomodules without consulting the Linac Group. This configuration greatly simplifies the rf distribution layout, and is more amenable to future upgrades of the machine to higher energy (the quads in this case may not have to be replaced). Use longitudinally separated quad and corrector magnets as opposed to combined-function magnets. This choice will eliminate the dipole fields that would otherwise be induced in the quad windings from persistent currents excited by changes in the corrector settings. Also, the quads in the upstream end of the machine may be superferric as suggested by the Magnet group. The BPM spec was not changed, but it may be in the future - the LET group has still not decided what BPM resolution we need. Within the linacs, measure beam energy and energy spread only in the electron undulator section and its counterpart in the positron linac (both are part of the Positron Injection system). The BCD recommends measuring it at two locations in the linac, but this does not seem cost effective (the beam energy and energy spread would still be measured at the end of the RTML and the beginning of the BDS). As for beam size measurements elsewhere within the linac, the only space readily available are the warm sections between the cryogenic units (it is difficult to install laser wires in a cryogenic environment). With the limited number of wires, local emittance measurements will require semi-invasive quad scans. The remaining changes on this page are updates of out-dated information On page 38: Nobu included the cryogenic section twice, so I deleted the second version.
Attachment: Main Linac Changes.doc
Description: Main Linac Changes.doc
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