From:	Anderson, Scott D. <sda@slac.stanford.edu>
Sent:	Tuesday, November 3, 2020 10:15 AM
To:	Wolf, Zachary R.
Subject:	HXR and LCLS beam line tunnel measurements with the pedestals only
Attachments:	LCLS_HXR_Tunnel_Bx_By_Fields.xlsx; LCLS vs LCLS-II Bx Mean Background Fields by Cell 
with only Pedestals.png; LCLS vs LCLS-II By Mean Background Fields by Cell with only Pedestals.png

Hi Zack,

I did find the LCLS undulator line pedestal only data which might be helpful since the new HXR cells 
didn’t get measured for their background fields.  I’ve attached an excel sheet which summarizes the HXR 
and this LCLS data.  Specifically the sheets are:

‘HXR Line MMF Diff’ is the HXR data with the MMF HXR bench background field subtracted.  This is the 
data I previously sent you in a file “HXR_Tunnel_MMF_Differences.xlsx”
'LCLS Line MMF Diff' is the LCLS data with the MMF HXR bench background field subtracted.
'HXR Line with Pedestals Only' is just the HXR mean data, of the three measurements for each cell, and 
the standard deviation of these measurements.  The mean data is what is used for the difference 
measurements.
'LCLS Line with Pedestals Only' is just the LCLS mean data, of the four measurements for each cell, and 
the standard deviation of these measurements.  The mean data is what is used for the difference 
measurements.  The data can be found at V:\MET\MagServe\MagData\LCLS\BeamLine\Pedestals

The cell numbers referred to are the LCLS-II cell numbering.  

I’ve also included plots of the LCLS and HXR data with their errors for reference.  It seems the two data 
sets mostly agree, but not always, which is curious since the measurements should have been made in 
the nearly the same locations for each cell.

Let me know if you have any questions.

-Scott Anderson