From:	Ayvazyan, Valeri <valeri.ayvazyan@desy.de>
Sent:	Mittwoch, 13. März 2013 11:50

*	During last run there wasn't any difference in field gradient between the first four cavities 
and the last for cavities. All cavities in ACC1 have approximately the same field 
gradients.
*	There is a possibility to change power balance between first four cavities with respect to 
other four cavities. There is a power divider on waveguide distribution path. This 
possibility was used long time ago.
*	We can't tune gradients for each cavity separately at FLASH, including ACC1. We can't 
even change the phases at ACC1 cavities separately (for other modules phases can be 
changed).
 
I guess you are interested in energy gain with full RF pulse length (800 us flat-top). The 
pulse length is important.
 
Actually gradient limits which are shown in LLRF panels are limits per cavity, you don't 
need to multiply them by cavity length.
 
Maximum energy gain reached in past with full RF pulse length are as follow:
 
ACC1  = 165 MeV;
ACC39 =  22 MeV;
ACC23 = 345 MeV;
ACC45 = 320 MeV; (here we have room for improvement  ~20 MeV by changing power 
balance between modules)
ACC67 = 430 MeV;