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

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

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)

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

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

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…..

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 7.12 7.19 7.01 6.98 6.96 7.56 7.56 7.55 7.55 7.53 8.78 8.67 8.65 8.65 8.56 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

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] 6.35 6.35 6.35 6.34 6.34 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……

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

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

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)

Example of status monitor Current version