1. L1S Jitter with AIP Modulator
Franz-Josef Decker
25-Sep-2014

2. L1S Phase Jitter History
0.04 deg  deg it is bad now
TDLY: Modulator pulse cuts into RF pulse
HV higher and then better jitter is new!
July 2014
Sep. 2014
TDLY: -5.7  -4.2 us
HV: 300  320 kV

3. L1S HV Scan
AIP modulator “allows” it
300 kV kV
Phase Jitter [deg]

4. AIP SCR Modulator Upgrade (before and after)
L1X shows similar behavior to L1S
Looks like timing jitter
July Sep 2014

5. L1S
Lost
July 
Sep. 
Best for Sep

6. More L1S Reminder: 100 ppm  0.05 deg
Lowest timing jitter Maybe thyratron worse

7. Thyratron back swing jitter
It shouldn’t have this two state

8. L1S is Main Source of DL2 E-Jitter
L1S phase is nearly 75% of energy jitter power, (DE/E =  %)
And phase is 86 % correlated to HV
Phase deg
86 %
HV counts

9. Summary New L1S modulator and Klystron setup is 2-3 times worse
It “seems” to point to SCR switched AIP upgraded modulator
Many more variations happened: new thyratron, 30120 Hz, -50  -75 V thyratron bias change, filter in trigger bypassed, LC for DQ-ing, Ross devider, …
To do: Secondary power supply, …