Minutes of A0 photoinjector (local) meeting
                        Friday March 19th, 2004

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

* attendees: Daniel, Jamie, Matt, Rodion, Kai, Markus, Helen, 
            Jamie R., and Philippe (recorder)

* Next meeting: Friday March 26th 11am in "the Motel"
        
	            *** NOTE SPECIAL TIME ***
* Plan for next week: 

-Monday:    - two pulse studies [Rodion/Jamie/Philippe]
-Tuesday:   - CTR bunch length measurement [Daniel]
            - redo the preliminary experiment on 
              9-cell phase shift versus gun gradient [Nick]
-Wednesday: - calibrate the UV diode in the cave [Jamie et al.]
            - 9-cell studies [Philippe]
-Thursday:  - 9-cell studies [Philippe]
-Friday:    - Continue round beam studies [Kai]


Discussions:

* Achievements of last week:

- Monday:
        -  starting at noon, 9-cell studies, a series of data to measure 
           the transfer matrix of the 9-cell cavity versus gradient of 
           the 9-cell were taken [Philippe]
           
- Tuesday: 
        -  round beam studies: measure the dependence of spot size on X3  
           versus solenoid. For the minimum spot size, measure the 
           evolution of spot size, emittance along the beamline. 
           
- Wednesday: 
        -  North cave running
           it was attempt to calibrate the UV diode in the cave, but 
           in an attempt to improve the laser, the laser beam quality 
           was deteriorated and not recovered untill late afternoon. 
           
- Thursday: 
        -  morning: CTR bunch length [Daniel] a series of autocorrelation were 
           recorded for different setting of the 9-cell phase
        -  afternoon: Plasma [Matt et al.]: The team tried to improve the 
           charge transmission downstream of the foil, but only 50-60% of 
           the charge produced at the gun is propagated to the experiment. 

- Friday
        -  Plasma experiment: The team continued working on transport, the goal 
           being to optimize the beam deceleration through the plasma and then 
           try to look for trapped charge. 
 
Other items:

Rodion reported on the analysis of the data he and Philippe took 
on March 8th. The experiment aimed at propagating to laser pulse 
separated by 20 ps (using the pulse stacker) and thereby generate 
two electron bunch. This allows a single-particle longitudinal 
dynamics study of, e.g., rf-effects. The two bunches spacing was measured 
downstream of the 9-cell cavity for a variety of operating phase for 
the cavity and rf-gun. The results clearly indicate a bunching/debunching 
effect depending on the phases (as one would expect). The experimental 
data were compared with simulations, and an offset not yet explained 
was found between experiments and simulations. The hope is now to 
iterate this experiment with the bunch compressor turned on and try 
to experimentally measure the R56 of the chicane. Another applications 
of this technique will be to test the CTR-based bunch length measurement 
resolution. 

Kai presented is results on the round beam studies. The analysis are 
prelimary and did not yet include comparison with simulations. 

Nick reported on an experiment he did regarding the gun: he varied the 
gun gradient (keeping the launch phase to ~45 deg), and for each value 
phased the cavity to have maximum energy gain. This enable a relative 
measurement of the electron time-of-flight up to the 9-cell cavity. His 
preliminary results in term of phase shift required to maxmimize the 
beam energy versus gun E-field are in discrepancies with his numerical 
results. More to come next week.  

-------
NOTES: few of you (the one not @fnal.gov) have not received the Minutes 
of the meeting since a couple of weeks. I apologize for this: this was 
due to computer center changes in security that prevented me from sending 
e-mails from a local machine (without knowing it!). I have changed this 
and also setup a web page where all the Minutes + Plans will eventually 
goes:

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

       
        -----------------------------------------

* Tasks concerning hardware 

H8/ calibration of upstream directional coupler and 
    insulator (Markus need to speak to Tim and with Kai to  
    schedule this STATUS?)
H11/ Some of the toroid need cabling to have signal available 
     out of the cave in the rack area
     (JAMIE, 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...)
H20/ what shall we do with the burnt doubling crystal? Who will 
     specify + order it?  CRYSTALS FROM CASIX ORDERED (FEB-04-2004)
     (NEW DOUBLING CRYSTAL WILL BE SHIPPED ON MAR-15-2004)         
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 efficency?                             
H23/ laser spare components list
     (Jamie, RECEIVED A FIRST VERSION JAN-30-2004)                                     
H25/ Software for the digital camera (Jason?)
H26/ trigger problem on a couple of CCD camera 
     (->Kai will look into it 03/2004)