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[bds 100] Re: draft of ATF2 PAC05 paper

Dear Frank, 

  Thank you, your questions are very useful. 
We certainly need to understand the implications 
of longitudinal instability. 

I am not sure about the double kicker. I know that 
there are plans to replace the present DR kicker, to improve 
vacuum, and perhaps this would mean that the other part of the 
double system kicker would need to be replaced? 
Tomo and Toshiaki, is this correct? 

For the beamsize monitor -- I would expect that 
the achievable resolution depend both on the wavelength 
and the angle. Axel, could you please clarify the formula
3.4 on page 35 of the ATF2 proposal, where it appears 
that dependence is only on the angle?

 Best regards

-----Original Message-----
From: Frank Zimmermann [mailto:Frank.Zimmermann@xxxxxxx] 
Sent: Tuesday, April 26, 2005 9:21 AM
To: bds@xxxxxxxxxxxxxx; Seryi, Andrei
Cc: Tomoyuki SANUKI; toshiaki.tauchi@xxxxxx; blair@xxxxxxxxxxxxx; Hans Braun
Subject: RE: [bds 98] draft of ATF2 PAC05 paper


Dear Andrei, Tomo, Tauchi san, et al., 

Thank you for sending the draft paper on ATF-2. 
It is well done and excellent.

I have a few comments, similar to those which I had sent to Tomoyuki san

earlier and mainly on page 3:

- I still do not understand why the BSM laser should operate in a higher

  mode. I think the Shintake monitor changes the resolution by varying the
  angle of the two laser beams and not by changing the mode. This monitor
  is different from a laser wire. Is this not correct? I do not see
  why a higher mode would be helpful or needed for this type of monitor.

- ATF already has a double-kicker system since many years. So I wonder why
  this is listed as a future improvement. Do you plan modifications to the
  existing double-kicker system? If so, maybe this could be made more clear.

- The large longitudinal jitter in the damping ring is not mentioned,
  but this could have a large effect on the stability of the spot size,
  given the limited momentum bandwidth of the final focus.
  [ The longitudinal oscillations were measured and described, e.g., by Naito et al; see
  Note that the amplitude of oscillation is several times the rms bunch length!
  A theoretical model was presented in a more recent ATF report by Sakanaka.]

- on page 3: 'Dumping ring' should be 'damping ring'.

- in the abstract: 'emittancies' should be 'emittances'

- on page 2: has better performance -> has a better performance

- on page 2: of ILC BDS design -> of the ILC BDs design

- on page 2: but has never -> but it has never

- on page 3: are needed to the ATF damping ring -> are needed for the ATF damping ring

I think my first three comments are quite relevant, and I would like to hear your feedback on these points, in case you do not share my opinion.

Many thanks and best regards,


-----Original Message-----
From: Seryi, Andrei [mailto:seryi@xxxxxxxxxxxxxxxxx]
Sent: Friday, April 22, 2005 11:07 PM
To: bds@xxxxxxxxxxxxxx
Cc: Tomoyuki SANUKI; blair@xxxxxxxxxxxxx; toshiaki.tauchi@xxxxxx; seryi@xxxxxxxxxxxxxxxxx
Subject: [bds 98] draft of ATF2 PAC05 paper

Dear All, 

The draft of PAC05 paper on ATF2 is available at

 Please send your comments or corrections.