LED stability pulser tests at RAL Paul, Barbara, Bob, Dave. Diffusing sphere. 1 to 7 fibres in. 240 fibres out 25 into SC01. Nichia NSPB500S LEDs. SC01 read out with 25 stephenson preamps. Fibres to inject into diffusing sphere.
Paul, Barbara, Bob, Dave
1 to 7 fibres in
240 fibres out25 into SC01
SC01 read out with 25 stephenson preamps
Quartz fibreSupplied by Applied Photonics, manufactured by Laser Components.
The Laser Components reference is CF01493-43.
The fibre has 550um inner silica core,
600um including silica cladding,
630um including a 'hard coating' (for mechanical strength)
750um including the plastic buffer.
Note that the plastic is EFTE ETFE (Ethylene TetrafluoroEthylene), a fluorocarbon-based polymer
Not usedFront fibre data, ABL ch 3 & 4, <0.1 normal sizePlastic fibre data ABL ch 7, appears double normalAll data, ABL ch 18: very high p*g=2.7, g=15.0
Indicates preamp gains are all close to each other
Signal from fibres out of diffusing sphere
Narrow width indicates good uniform illumination of fibres with sphere
Target:Mean output 120 GeV
Some way to go!
With 7 quartz fibres into sphere, mean signal size 20 GeV
Want 120 GeV
Must account for crystal and VPT darkening at LHC
Should start with a system capable of delivering 200 GeV
Mike A. be named the "VPT Stability system coordinator". This is part of a bigger issue.
Be an ESSENTIAL part of design of the blue LED stability/backup calibration system.
Mike has make a preliminary sketch of the functionality that one needs Hirosky and Andelin are working with him on the design of driving electronics to optimize the blue LED light yield and will take over from Dave Phillips the remainder of the testing as soon as Dave finishes his note on the present results.
Mike's work: in UVa to finish the burn-in boxes for FPIX. We delivered two boxes to Fermilab and they are working fine so he can put systems together.
Plus he has the UVa group already involved with the LED work and feeling that they have some stake in it.
Get support by US CMS for the construction of the system (in addition to the flashers themselves, there is the issue of synching with the beam structure, the slow controls and a host of things to think through).