1. 2011/ 07/06 Jacqueline Yan IPBSM
ATF2 Meeting
2011/ 07/06
Jacqueline Yan
IPBSM

2. Laser Start Up Problem Two weeks ago…. Laser could not restart
after refilling chilling water
Due to air bubbles ?? Not sure…..
Tried pumping bubbles out and other ways throughout the week
but to no avail !!!
Arranged for Spectra Physics to come fix it last Monday
But somehow got laser to turn on right before he arrived ?!?!
Power and build-up measured normal

3. Spectra Physics Changed filter Adjusted power
Received advice on digital laser control
Connect with RS232C
Convenient for detecting
what affected interlock
We need to know what actions would cause interlock failure
Asked for extra information (see next few pages)

4. Ray PRO interlock system
Laser head
Cover
Cooling water
flow amount
temperature
Cable connection
Laser power supply
Cover
Internal cooling water
Amount inside tank
Flow amount
External cooling water pressure
“ accessory plug” :
external interlock plug
Controller (on top of power supply)
Connection to interlock

5. Interlock Checklist
Switch on external cooling water:   pressure 2.5～4 MPa
Cover of laser head and laser power supply in place
External interlock key switched OFF
Enough internal cooling water inside tank
“Low Water” indicator lamp OFF
Lamp energy at START position (on controller)
Switch ON “ENABLE”
 Pump begin revolving  “Interlock fault” indicator lamp go OFF
CDRH should go off and Simmer ON within 10 – 15 sec

6. Possible causes for laser start up failure
(1) External cooling water pressure deviated from set value
(2) Internal cooling water:
too close down to limit
Insulation deficit (purity)
(3) Flash lamp degradation
(4) HV system faults
ect…..

7. Internal Cooling Water Purity
We measured internal cooling water purity
Higher value (Unit ：　Ω cm) = higher purity
ATF sample [e5 Ω cm]
New cooling water
Cooling water in tank
Similar values in Jan 2011
Water already in tank is even purer than new water from box!!!
(because of filter)
 We can be sure water filter functions well
So water purity was not the cause

8. It happened again!!
Water was getting low, so we tried adding same cooling water as what caused the previous incident
Laser stopped again!!!!!
Suspected problems:
water from the “old box” is unpure  measured purity of this old water
Same Cooling Water as last incident [e5 Ω cm]
value is low, but not significant enough to be sure this is the problem
(2) Cooling water temperature too high: box stored outside laser room
If this is the reason, laser should recover by itself
Let it sit for a while……

9. It happened again!! This morning (7/6 ~ 10:30 am) tried again
Laser started!!!!!
Cooling water temperature was too high (?)
　air bubbles disturbed flow sensor(?)
Some time needed for self-adjustment after refill
We will…….
store water inside laser room
refill some time ahead of beam time
We are not sure of the reason  need to investigate all possibilities

10. Status monitor for IPBSM
IPBSM group may not be present during all beam tuning shifts
 we need IPBSM status monitor that anyone can use / understand
Green = OK
Red = call a IPBSM member
The current status monitors I and II cannot provide adequate info
Requested Kanto Jouhou to help us create this before autumn beam run

11. Status monitor for IPBSM
Mirror Actuator x 14
Rotation stage (upstream)
Rotation stage (downstream)
Delay line piezo
temperature x 14
Nitrogen flow
IP-BPM  beam position (x, y)
Beam angle (x, y)
Chamber vacuum
BG Shower
Signal Shower
PSD x 12
PSD IP beam position
Phase monitor x 2
Laser power
BuilUp
Laser piezo
Attenuator
Gamma Shutter
Laser Shutter
IP Mover
BG Monitor IN/OUT
Collimator
CsI(Tl) HV
Reducer
TD4
Prism Stage
Focal Point Scanner (upstream)
Focal Point Scanner (downstream)
Cross Angle
ICT-DUMP
CsI(Tl) ADC count x 12
BG Energy
Signal Energy
Laser Timing
Beam Timing
Laser - Beam Timing
86! parameters to monitor
2 display panels needed (control room, DAQ room)

12. Example of status monitor
Current version