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[Ext-GDE-52] BDS Change Config Request - July 29, 2006



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
ml-ccb@xxxxxxxxxxxx and/or ml-ext-gde@xxxxxxxxxxxx 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: toge@xxxxxxxxxxxx
  voice: +81-29-864-5224
  fax:   +81-29-864-3182
--- Begin Message ---
 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

Attachment: BDS_config_CCR_Jul28.doc
Description: BDS_config_CCR_Jul28.doc

Attachment: bds 23apr2006_ccr_1414_Jul28.doc
Description: bds 23apr2006_ccr_1414_Jul28.doc


--- End Message ---