Monitoring System Requirements
From GlueXWiki
| Characteristic | LED/fibre | LED/wire |
|---|---|---|
| Dead/alive or on/off | ≤ 15% | |
| Dynamic range of input (number of photoelectrons) | typically 100 | |
| Requirement on absolute light input | none (PRIMEX might have) | 150 pe on module |
| Variation in arrival times of cal pulses | ~3 ns | ≤ 2 ns |
| Time stability gain and timing (one channel) | ≤ 10% in 6 months | |
| Temperature stability (likely cause of time stability) | 1o causes 3% gain change | |
| Location of calibration input | From front to monitor rad damage | light guide tapered side |
| Geometrical constraints | Approximately 90% of front 4x4 cm2 area available | packing of WC and LGs, LED fitting, cable routing |
- Comment: Time (and temperature) stability most important.
- Comment: Option of delivering a range of light intensities important (e.g. using various filter settings).
- Comment from Werner: The flexibility in the use of the LED would be very useful for the start counter. Christina: Still need to test stability.
- Questions to Matt: What uniformity could one expect from the plexiglass input system? How many fibers were used to pulse the plexiglass, i.e. how often were they spaced?
- Comment: Matt drew attention to an LED pulser by Paul Smith which might be a useful reference.
