Brenda Dingus Jan 2005 New Laser Calibration Status  New Laser vs Old Laser  Safety  Pond Data  Outrigger Data  How to Combine?

Brenda Dingus Jan 2005 Awesome New Laser NEWOLD Nd YAG laserNitrogen laser Solid State (no consumables) Gas Tube (replace ~1/year) 0.2 nsec pulse2-4 nsec pulse 532 nm~470 nm 26 microJoules/pulse~100 microJoules/pulse 3 sq mm beam80 sq mm beam pulses/sec<10 pulses/sec

Brenda Dingus Jan 2005 SAFETY  Class 3b laser  Due to high intensity of laser, a single pulse specularly reflected into the eye is hazardous.  Requires LANL Integrated Work Document (IWD)  Safety Interlock on Plexiglass Cover  Hazard light on outside of shed  DO NOT ENTER LASER SHED, IF YOU HAVE NOT SIGNED IWD  If you want to sign IWD, you must  Take LANL Laser Safety for Class 3b & 4  Have LANL HSR approved eye exam  Read IWD

Brenda Dingus Jan 2005 Laser Calibration LASER Computer Controlled Optical Filter Wheel Computer Controlled Optical Fiber Switch Optical Fiber ~ 30 Fibers to Pond & ~ 30 Fibers to Outriggers Computer Controlled Delay Generator Prompt Pulse To Common Stop of Time to Digital Converter Monitor Photodiode To Front End Board & TDC

Brenda Dingus Jan 2005 Laser Light Output Stability Time (hours) Photodiode hitot (ch) Pond Calibration of 1000 Hz x 35 filter wheel positions x 30 laser balls takes ~12 hours Each ball takes ~24 minutes Photodiode hitot varies by <5 ch in 24 minutes Still need to calibrate photodiode hitot

Brenda Dingus Jan 2005 Timing Stabile of Delay Generator Timing of monitor photodiode shows no skips even for short time intervals Long term stability also < 0.5 nsec Time (hours)Photodiode histart (ch)

Brenda Dingus Jan 2005 Pond Calibration Hi or Lo Start Hi Lo Hi or Lo ToT  30 laser balls in pond  Central balls can calibrate ~30 top layer pmts to several 1000 pes and ~100 top layer pmts up to several 100 pes Typical Top Layer Slewing Curve

Brenda Dingus Jan 2005 Outrigger Calibration  Laser is bright!  Combine 30 fibers entering laser shed to 3 fibers coming out of optical switch  Each of 3 fibers requires different delay due to different cable and fiber lengths  Additional optical filter is required for most outriggers  29 outriggers need x light sent to pond ball  121 outriggers need x light sent to pond ball  19 outriggers need x light sent to pond ball  4 outriggers need 1 x light sent to pond ball

Brenda Dingus Jan 2005 How to Combine?  What is relative offset between top/bottom/outriggers?  Current monitor histogram looks problematic.