Activities of FNPL from 01/23 - 01/28
                        Friday Feb 4 th, 2005


     
      minutes at: http://nicadd.niu.edu/fnpl/Operation/Minutes/



* Plan for next week:

   - Monday, Tuesday:
	- laser study [Jianliang, Rodion]
	- 200 kW klystron test
	- check on 3 MW klystron (cannot go above 35 MV/m)
	
   - Wednesday, 
	- round beam:	- emittance measurements,
			- take date with laser mask
    
   
   - Thursday, and Friday: running beam
	- flat beam: 	- work on improving emittance ration
			- do a clean measurement of e+/-=e0+/-L
			- flat beam emittance vs B and sigma_c
    
* Last week activities:
	- laser work (Monday): Streak camera measurement of the UV 
	  laser pulse revealed the pulse is two-peaked. Reducing the 
	  oscillator bandwidth from 21 Angrstron to ~ 18.5 Angstrom 
	  cleaned the pulse estimate of the pulse width was 3 ps (rms)
	- In parallel the CW autocorrelator was used to measure the 
	  IR pulse after compression in the test compressor. Jianliang 
	  reported a value of 2.7/sqrt[2]= 1.9 ps FWHM (= 800 fs rms!) 
	  this results is very encouraging and support our thoughts to 
	  use the present oscillator (together with a compressor) to 
	  perform a first set of electro-optics imaging experiments. 
	- the spot size distortion in the 2 pass were investigated -- no  
	  cure so far  -- it was noted that the 2-pass performance is a 
	  factor 2 below its noiminal performance (now only 35 times 
	  amplification compared to 70 times nominal amplification)
	   
	- the gun water system repair was finished Wednesday afternoon 
	  at 3pm. Wednesday afternoon was used to tune the gun temperature. 
	  Philippe showed correlation plots between temperature and 
	  reflected power that show the optimum operating temperature 
	  (after equilibrium and measured at the skiq) is 38.9 deg C. 
	  With this temperature the reflected power reading on the 
	  diode is about 1-2 mV; this nominal temperature is different 
	  from the optimal temperature suggested earlier (39.3 deg C) and 
	  it is presently unclear why. Thursday morning it was noted that 
	  the reflected power was 10-15 mV when we started the gun but
	  eventually dropped to 1-2 mV after a couple of hours. The temperature 
	  measurement and feedback system is 40 (?) meters far from the gun 
	  so there must be some temperature gradient between the rf-gun and 
	  the skid. Maybe at some point we should take care of insulating the 
	  pipe. 
	  
	- Thursday and Friday were dedicated to flat beam measurements. The 
	  prime task was to measure dispersion along the bemline by scaling 
	  all the magnets downtream of the TeSLA cavity. Preliminary 
	  measurement were made but further are needed to exercise our 
	  measurement technique and be confident on the dispersion measured. 
	  
	- Friday afternoon we tried the 5 beamlets mask sent by University 
	  of Rochester (Adrian had the University's workshop machining a 
	  5 dots mask). The first experiment looks promising and more need 
	  to be done next week.  
	  
	  
	
	
	
	
ACTION ITEM updated:
Mon Feb  7 16:08:21 CST 2005

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)
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]
H33/ laser fluctuation since June 1st week [FIXED?]
H34/ Need more work on power supply + devise a way to measure
     the current being put out to the magnet [Jamie]
H36/ laser room/table vibration studies [Rodion]
H39/ streak camera new optics for plasma OTR and UV laser 
     streaking. [Jamie, Greg, Rodion, Philippe]
H40/ installation of UIUC experiment, beamline design [Philippe] 
H41/ OTRI experiment [Greg]
H42/ revisit EO sampling experiment [Jianliang]
H43/ laser cooling system upgrade 
     [Jamie-> discuss with Adrian, Jianliang,Rodion]
H44/ do we need to get our rf system out of the TeV LCW and Why [Jamie/Philippe]

#.44

from Adrian Melissinos:

NEEDED LASER STUDIES:

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
4. _harware_: replacing all coolers with new system IV +
   use existing system III as back-up (see H43)
5. pulse stacker studies, new pulse stacker R&D (see H13)