Minutes of A0 photoinjector group meeting
                        Monday August 2nd, 2004

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


* Next meeting: Monday August 9th in WH10

* Plan for next week:

- Monday:    Flat beam experiments [Yin-e]
- Tuesday:   Flat beam experiments [Philippe]
- Wednesday: high charge beam dynamics studies [Matt/Jamie R.]
- Thursday:  high charge beam dynamics studies [Matt/Jamie R.]
- Friday:   -morning: proton driver phase shifter study [D. Widldman]
            -afternoon: Flat beam experiment? [Philippe/Yin-e (?)]


Discussions:

* Achievements of last week:

- Monday: Took a set of data on 81 MHz phase measurement [Djifa]
      in the meanwhile  re-installed the skew quads {Jamie S.]
      (the power supply have ben zeroed properly -- we think)
      
- Tuesday: Did some preliminray beam test with the skew 
      quads [Jamie/Philippe]. Took more data on the 
      phase measurement [Djifa]
      
- Wednesday: Took a set of data on round magnetized beam, 
      did thorough checks on skew quads, and everything appeared 
      alright: when degaussed the quadrupole do not anymore 
      induce some coupling [Yin-e/Philippe] 

- Thursday: Data on CAM-dominated round beam; the polarity of 
      the first solenoid was switched to enhanced [Steve et al.]

- Friday: a  preliminray flat beam was generated, with quads 
      1, 3 and 4 of the round-to-flat beam transform, preliminray 
      data on beam evolution though the adapter, and emittance were 
      taken. Quad strength were calculated from simulations and 
      are within 10-20% in agreement with the one dialed in the 
      experiment. A more controlled experiment will take place 
      this Monday and Tuesday to repeat the measurement, after few 
      modifications (e.g. X8 needs a larger field-of-view) 
      [Philippe/Yin-e]
     
* Discussion:
     - Djifa presented her measurement on phase jitter of the 81 MHz 
      signal fed to the oscillator. She presently observed phase 
      jitter of the order of 2 deg. Next step she is going to compare 
      this signal with the error signal commonly use to tune the laser. 
     - Yin-e presented data on angular momentum versus charge, there 
      is no dependence as one would expect if the beam was angular 
      momentum dominated
     - Philippe showed some data of angular momentum versus spot size 
      on the cathode; the expected quadratic dependence is measured
     - Philippe showed measurement of beam evolution in the round-to 
      flat beam transformed agreement with on-line simulation is quite 
      good, but more measurements are needed to pin down the experimental 
      condition (this week). 


* Tasks concerning hardware

Sun Aug  1 10:43:44 CDT 2004
ACTION ITEM updated:

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]

H26/ trigger problem on a couple of CCD camera
     (->Kai will look into it 03/2004)
H28/ Problem with emittance measurement at X7 (Philippe 04/16/04)
H29/ Need daily monitoring of the laser parameters (Jamie/Rodion 04/23/04)
     [OSCILLATOR BW AT 131.225.136.161:8000/~laser]
H32/ Digital camera from SONY(?): camera sent back waiting for new ones
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]

from Adrian Melissinos:

NEEDED LASER STUDIES:

1. Study of oscillator bandwidth versus length of
   compressed pulse. Measure IR 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