Dear Colleagues of the WWS,

    You may have heard that a change in the BDS Baseline is being reviewed by
the GDE CCB.  In short, the change is the following:

   The BDS continues to assume supporting two IRs, but in doing so
   would like to consider both IRs to be configured for 14mrad
   beam crossing angle now as the Baseline. Likewise, both IRs are to
   be located at Z=0 in the common collider hall.    

    The 20/2 mr alternative will continue to be studied with R&D.

    The GDE is eager to get comment from the WWS regarding this Baseline change.
The WWS-OC plans to prepare a statement on this change to the GDE CCB.  The MDI Panel 
will provide advice on the technical issues.  The concepts will also be solicited by the WWS-OC
for comment.

    The messages below provide further details on this proposal.

         Best regards,

         Jim, Francois, and Hitoshi

    

_______________________
James E. Brau
Physics Department
  and Center for High Energy Physics
1274 University of Oregon
Eugene, OR 97403-1274
(541) 346-4766

On Sat, 29 Jul 2006 23:31:29 +0900 (JST), "N.Toge" <[log in to unmask]> wrote:
> Dear Jim, Francois, Hitoshi,
> 
> Nobu Toge from CCB/ILC-GDE here.
> 
> I am writing to ask your comments and remarks as Co-chairpersons of
> WWS, concerning the BDS change configuration request that was submitted 
> earlier today. As you see in the attached emails, the Beam Delivery 
> System (BDS) Area Group (AG) leaders are proposing,
> 
> (1) to revise the beam crossing angles at the two IRs from 2mrad/20mrad
>     to 14mrad/14mrad, and
> (2) having the two IRs located at Z=0 sharing the same collider hall,
>     as opposed to the previously "staggered" layout.
> 
> While the anticipated cost saving is a big issue for GDE and for that
> reason, we are asking opinions of relevant technical/global experts,
> we also recognize the critical importance of hearing inputs from 
> the experimenters who intend to work on physics once this machine comes 
> into a reality.
> 
> The information of primary interest from you is your comments, reactions
> and assessment on anticipated impacts concerning the physics research
> potential that this configuration change might incur. We are interested
> in hearing both your expert insights as well as opinions (average,
> distributions, etc) of the WWS members and their friends that you have 
> access to.
> 
> I would very much appreciate your insight and analysis on this matter.
> We might ask you some additional questions while discussions within
> CCB ensure in the coming days. So our communication could be somewhat
> interactive.
> 
> Thank you for your attention and cooperation on this matter.
> 
> Sincerely,
> 
> - Nobu Toge (KEK, Accelerator Lab)
>   email: [log in to unmask]
>   voice: +81-29-864-5224
>   fax:   +81-29-864-3182
> 


------------------------------------------------------------------------
> Dear Colleagues,
> 
> I am announcing that CCB has received a change request for the Beam
> Delivery System (BDS) section of ILC Baseline Config Doc from A.Seryi,
> who is co-representing the BDS AG with D.Angal-Kalinin and H.Yamamoto.
> 
> This change request mainly relates to the BDS layout outline.
> The BDS continues to assume supporting two IRs, but in doing so
> would like to consider both IRs to be configured for 14mrad
> beam crossing angle now as the Baseline. Likewise, both IRs are to
> be located at Z=0 in the common collider hall. These revisions
> are an attempt at reducing the construction cost of this system
> while maintaining the fundamental BDS functionalities as put forward
> and accepted at the time of Snowmass workshop the last year.
> It is proposed that two IRs with 20mrad/2mrad crossing angles,
> which have been our Baseline so far, be reclassified as an Alternative
> Configuration, and the requesters state that the study for
> this (20/2) case will still continue.
> 
> The requesters suggest Class 2 as classification for this change
> request. The CCB chair tentatively agrees to treat this as Class 2,
> pending analysis of the associated cost-delta and impacts, in
> particular, with respect to the detector design.
> 
> According to the protocol for Class-2 change requests, I am doing
> the following.
> 
> - I am assigning T.Markiewicz, G.Blair, K.Kubo (all to be
>   confirmed), plus myself, to act as CCB co-reviewers.
> - I will be asking
>   * GDE Cost Engineers for their assessment on the cost
>     impact concerning this change request.
>   * Representatives of MDI and representatives of WWS
>     for their assessment on the physics and technical
>     impacts on the detector design and physics experiments.
>   (I am writing formal request letters to them shortly.
>    Please, note that as CCB engages in the review, it might
>    ask additional inquiries later.)
> - A CCB recommendation report will be drafted within at most
>   two weeks, and will be sent to EC (with cc: to the entire
>   GDE) for their final decision.
> 
> 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
> [log in to unmask] and/or [log in to unmask] by the end of
> Thursday, August 3, PDT.
> 
> I urge the recipients of this notice to share the information
> and discussion of this change request with non-GDE members within
> the community.
> 
> However, I ENCOURAGE the remarks and comments from non-GDE members
> be funneled through adequate channels of GDE (i.e. MDI contact,
> WWS contact, Board chairs, AG/GG/TS group contacts).
> 
> My thanks in advance for your cooperation and understanding.
> 
> 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
> RDR-related information repository for BDS is found at
>    http://www-project.slac.stanford.edu/ilc/acceldev/beamdelivery/rdr/
> 
> Sincerely,
> 
> - Nobu Toge (KEK, Accelerator Lab)
>   email: [log in to unmask]
>   voice: +81-29-864-5224
>   fax:   +81-29-864-3182
> 


------------------------------------------------------------------------
> 
>  Dear Nobu and Colleagues in CCB, 
> 
> We are submitting a change request which 
> is described in the attached files. 
> 
> The file "BDS_config_CCR_Jul28.doc" describes 
> the change request and also gives a preview of other 
> change requests which are being discussed/prepared.
> 
> The file "bds 23apr2006_ccr_1414_Jul28.doc" 
> is an updated version of BDS BCD which was edited
> with Track changes switched ON.
> 
>  Best regards, 
>   BDS Area leaders
>   Deepa Angal-Kalinin, Andrei Seryi, Hitoshi Yamamoto
> 


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