Monitoring laser
Contents :
I PresentationII Safety &triggerIII AnalysisIV Next actions
Monitoring laserDavid BAILLEUX
1
Krypton lampYLF
Ti:S
YLF
Ti:S
Output
I Presentation
David BAILLEUX
3Monitoring laser
YLF Ti:S 527nm 440nmPulse energy 10mJ 1mJPulse width 40n 40nsPulse power 250kW 25kW
YLF = Yttrium Lithium Fluoride
Principe: optical pumpage..
I Presentation
David BAILLEUX
4Monitoring laser
Pump + heat exchanger
Cooling:
Transfo (110V)Inlet
Outlet
Laser Settings
I Presentation
David BAILLEUX
5Monitoring laser
Remote controls:
- wavelength- energy
Record data for 2 lasers :histogram and history
- energy- pulse width- pulse center- wavelength
Waveform Display
III Safety, trigger
David BAILLEUX
6Monitoring laser
Safety:A TTL level input is required on the safety module.
No TTL signal shutter of YLF laser closed
This TTL signal is off if :- the door is opened,- the main fiber is broken, or no light on pin diode.
An interlock is provided to close the laser shutter (pump) in case of unexpected opening of the laser room door.The interlock also functions if optical fibers were accidentally broken or removed. This is achieved by the level 2 TTL input, provided byFanouts …TTL signal at high level if the level fanouts receive laser pulse.
III Safety
David BAILLEUX
7
External trigger :
Timing signal form YLF laser
External trigger
Level TTL signal
TRIGGER = Timing signal
EVT
PIN NIVEAU 2
FIBRE HS
GENE porte rapide
END of porte
SECURITY LASER
Security laser(TTL level)
4 us
GENE T0(manual switch)
FIBRE OK
*T
*T > tps de transmission ds las fibres + tps de propagation du signal ds les cables.
No event no more light security laser = low level shutter closed
David
BAILLEUX9
III Analysis
Monitoring laser
26 A working point
YLF 2000 mW
Ti:S 110 mWEnergy from
0 to 100 %, soft0 mW Output Ti:S 1,1 mW
Neutral density filter 1/100
Results after calibration
III Analysis
David BAILLEUX
10
/mean=1 % /mean=3 %
/mean= 1.6 % /mean= 2.1 %
New lampPlot from 2 Oct
(27 Oct)
Old lamp(31 August)
YLF
YLF ENGY YLF FWHM
David
BAILLEUX11
New lampPlot from 2 Oct
(27 Oct)
Old lamp(31 August)
/mean=7.7 % /mean=7.5%
/mean= 4.9 % /mean= 4.3 %
Ti:S ENGY Ti:S FWHM
Ti:S
David
BAILLEUX12
III Analysis
Variations p-p:40%
With new lamp(27/09)
End of stabilization
Variations p-p:5%
In August
66 h
III Analysis
Variations p-p: 10%
With new lamp
Long term
David BAILLEUX
13
10 j
- Lamp has to be replaced every 2000 hours (83 days), Degradation is about 10% at 1000 h and 20% at 2000 h
- Wavelength : problem from 440 to 500 nm : no light at 500 nmfine tuning needed, service from Quantronix (similar problem in Caltech)Forecast : ready in 2 weeks ?
-Next year: software improvement: Now data are recorded every 1 s (scope limitation)
Laser events = 2000/mn DAQ record 20 events/mn (0.3 Hz) data during all test beam
probe for temperature inside the laser barrack new laser installation Feb 2003 ?
Summary