Dear Colleagues, I am announcing that CCB has received a change request for the BDS section of ILC Baseline Config Doc from A.Seryi who is representing the BDS AG. This change request relates to a likely scenario for the gamma-gamma upgrade of the BDS and IR to thoroughly examine in the timescale beyond RDR. The requesters suggest Class 1 as classification for this change request. The CCB chair concurs, so it will be treated as Class 1. I have asked G.Blair and T.Markiewicz 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, May 19, 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 BDS-related RDR materials are compiled and posted at http://www-project.slac.stanford.edu/ilc/acceldev/beamdelivery/rdr/ 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-381] change request in BDS: gamma-gamma upgrade
- From: "Seryi, Andrei" <seryi@xxxxxxxxxxxxxxxxx>
- Date: Tue, 16 May 2006 21:18:10 -07001) Requester¡Çs contact information. On behalf of BDS area leaders, Andrei Seryi, seryi@xxxxxxxxxxxxxxxxx 2) Concise summary of the Change Request. The modified text include description of a likely scenario for gamma-gamma upgrade. Requirements for gg IR design and beam dump for gg are briefly discussed and references are given where more information can be found. It is discussed that either 20mrad IR or 14mrad IR may be upgraded to 25mrad for gg by introduction of a bend between FF and E-collimator. It is discussed that due to the assumed need for downstream diagnostics in e+e- and the need for reversibility of gg upgrade, it is beneficial that crossing angles for e+e- and gg options are not the same, and sufficiently different to allow independent and sufficiently shielded beam dumps. It is suggested that more study should be done after RDR, namely during TDR time frame. The list of R&D items is given. 3) Replacement text for the relevant part of BC descriptions. The Word file with track changes ON, is attached 4) Classification in requester¡Çs view. This is probably Class 1. From one point of view, this added text can be considered as insertion of a missing section (class 0), but the implications may be not minor. However, one need to note that there should not be implications for RDR work and cost, but only for TDR time frame. 5) Reasonably detailed descriptions and reasons for the Change Request. The gamma-gamma upgrade scenario was not described in BCD but need to be discussed, as gamma-gamma option may be important for physics. 6) Assessment of the impacts of the change in requesters¡Ç view. The change will allow to include in BCD the description of one of the most likely (as understood by us at present) gg upgraded scenarios and focus on studies of the technical feasibility in TDR time.
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