Minutes of A0 photoinjector group meeting
                        Monday June 14th, 2004

           http://home.fnal.gov/~piot/FridayMeeting/Minutes/
           

* Next meeting: Monday June 21th, 2004

* Plan for next week: 

**** To be determined after the photocathode-laser has been fixed (see below) ****


Discussions (short meeting on Friday June 4th):

* Achievements of last week:

- Monday:
        -  Measurement of R56 of the bunch: took one more set of data, 
           [Rodion], during this experiment, some data on CTR autocor-
	   relation (for a double pulse) were taken [Daniel]. 
           
- Tuesday/Wednesday:
        -  beam initially dedicated to flat beam studies, however due 
	   to to large charge fluctuations, a shot-to-shot transverse 
	   spot variation (of the laser + e- beam), no data could be 
	   taken. Instead few test on camera were performed and few 
	   camera were moved around to improved signal quality (with 
	   better camera) at the location needed (essentially upstream 
	   from the chicane) [Yin-e/Philippe]
           
- Thursday: 
        -  remote operation from Berkeley, same problem as Tuesday 
	   and Wednesday prevented any achievements [Steve/Kai/Jason]
           
- Friday: 
        - no beam, Rodion, Nick and Kamie look at the laser, Nick and 
	  Rodion later find some problem with the oscillator, (misalignments). 
	  When misalignment were corrected the laser operated at much lower 
	  power (Rodion report 10 % coupling in the fiber). Nick and Rodion 
	  suspect the mode locker not to be working properly and it was decided 
	  at the meeting to install the spare mode locker and see if things 
	  improved [PS: we have no more rod spare for the oscillator they 
	  should come on July 8th]

* Other discussed items:
        - Katja Honkavaara (from DESY) reported on the TTF-2 experience 
	  with digital camera. Overall data quality taken from such devices 
	  seem much better despite the flaky operation of the camera (need 
	  reboot/ power cycle time-to-time for reason not understood). DESY 
	  use BASLER camera similar to the one we have been operation for  
	  a few months (without major failure). The camera that died at DESY 
	  had no shielding. 
	  http://home.fnal.gov/~piot/FridayMeeting/Minutes/min_Jun14_04katja.pdf
	  From DESY and our experience (along with discussion Jason had with SONY), 
	  it seems the SONY camera has more advantage with respect to the BASLER.  
	   
	 
	  
        - Goerge Gollin (from Urbana-Champaign) reported on his expression 
	  of interest to use A0 beam for testing a kicker concept for the 
	  TESLA damping ring.  
	  http://www.hep.uiuc.edu/home/g-gollin/Linear_collider/A0_committee_presentation.pdf  

                   
* Tasks concerning hardware 
ACTION ITEM updated:
Mon Jun 14 19:11:40 CDT 2004

H8/ calibration of upstream directional coupler and 
    insulator (Markus need to speak to Tim and with Kai to  
    schedule this STATUS?)
H13/ Pulse stacker, what do we do? (Rodion)
H14/ air coil steerers, Kai will gather all the paper he has 
     and we will decide whether we can give this project to one of 
     the NIU engineering student
     (Kai, STATUS: nobody at NIU picked up this project...)
H21/ the laser uniformity problem can this be due to the new (since 
     late summer) tight focusing in the doubling crystal area to 
     improve conversion efficiency? On going work [Rodion]                            
H25/ Software for the digital camera (Jason -- DONE); Now need 
     to choose which camera we are going to use [Jason/Markus]
H26/ trigger problem on a couple of CCD camera 
     (->Kai will look into it 03/2004)
H27/ The temperature sensors on the laser components need to be 
     wired and archived on ACNET (Jamie 03/26/04)
H28/ Problem with emittance measurement at X7 (Philippe 04/16/04)
H29/ Need daily monitoring of the laser parameters (Jamie/Rodion 04/23/04)
H30/ Need monitoring of laser oscillator spectrum from HP spectrum 
     analyzer (Jamie 05/21/04)
H31/ A/C problem in laser room [Since early May, NOT YET FIXED on JUN 14 !!!!]
     (Jamie)
H32/ Digital camera from SONY(?) need to be ordered
     (Jason)
H33/ laser fluctuation since June 1st week
from Adrian Melissinos:

NEEDED LASER STUDIES:

1. Study of oscillator bandwidth versus length of 
   compressed pulse. Measure IT length using stepping 
   autocorrelator
2. beam profile (wavefront) studies both in IR and UV
   in laser room and on virtual cathode. Use spatial filters
3. study of doubling and quadrupling efficencies with old 
   and new crystal, take a tuning curve

POSSIBLE LASER UPGRADE PROJECTS

1. Measure IR pulse length before compression (use diode?) 
   implement cw autocorrelation
2. Install new beamline between multipass and 2-pass -- 
   install spatial filter, rebalance 2-pass amplifiers
3. Relay imaging UV from laser room to cave 
4. _harware_: replacing all coolers with new system IV + 
   use existing system III as back-up
5. pulse stacker studies, new pulse stacker R&D