[PEPPo] beam time estimates

[Eric Voutier]

Dear all,

working on the beam time estimate for the proposal, I came to two limits 
that I would suggest we
discuss on monday and adress in the proposal.

- The present philosophy of the experiment : electron calibration of the 
analyzing power and the subsequent
    G4PEPPo simulation package
- positron measurements with an analyzing power extracted from 
"calibrated simulations with electron",
   possibly with the measured value if we succeed to match the electron 
and positron response.

===> we should discuss if this philosophy could be acceptable for the PAC

- expected experimental assymetries in the integrated method are ranging 
from 1000-8000 ppm.
   I removed the settings, like 1 MeV/c leading to ~200 ppm asymmetry.

===> this impact the control of systematics to be discussed also

- Counting rate : I limited the detector count rate to 1~MHz which in 
turns limits the beam current for one
   setting at 34 pA. We should discuss this limit either from the 
detector side or the beam side. My recollection
   is that the PMT basis are designed for 2 MHz and  1 year life-time, 
but dont recall the energy deposit considered
   for this estimate.

===> a reliable minimun achievable current value together with the 
technology to get it is important to convince
           the PAC

- Positron data : It is of course the opposit of electron data and we 
should increase the beam current to 10µA
   to get respectable accuracies and beam time within the integrated 
method scheme. I dont expect the
   semi-integrated method to be more efficient in beam time but "only" 
more comfortable wrt a 1-2% asymmetry.

====> In terms of power deposit in the target and radiation budget, what 
are the curent limits we can expect ?

These are the main questions I came to and that I would like to share 
and discuss with you to make sure that we have
  the necessary argues to convince the PAC.

  Best, Eric




-------------- next part --------------
A non-text attachment was scrubbed...
Name: voutier.vcf
Type: text/x-vcard
Size: 315 bytes
Desc: not available
Url : https://mailman.jlab.org/pipermail/peppo/attachments/20110626/dfb37ec2/attachment.vcf