Difference between revisions of "Monitoring System Requirements"

Revision as of 18:07, 8 December 2010

**DRAFT Table of System Requirements and Comparison**
Characteristic	LED/fibre	LED/wire
Dead/alive or on/off	yes	yes
Timing check/offset	yes	yes
Relative gain check	yes	yes
Linearity check	low end (a few times one LED) only	low end (a few times one LED) only
Temperature stability	yes, sensors in box	sensors in areal spread?
Tower row flashing	yes, multiplexer	yes, multiplexer
Simultaneously flash both ends	no solution yet	no solution yet
Location of LEDs input	Boxes at outer edge of each module, fibres	LED+board on light guide, LPCM in rack
Geometrical constraints	mechanical/fragility/replacement are serious concerns	none; easy to install
R&D done	Some, solution not preferred	Extensive, mature solution exists
Cost	Not costed	quotation exists (getting stale)

Details: Minutes/notes from December 6, 2010
Comment: Time (and temperature) stability most important.
Comment: Option of delivering a range of light intensities important (e.g. using various filter settings). Athens: test stability of LEDs at low output (near threshold) to see if this can be used as an additional check point in our monitoring.
Comment: The flexibility in the use of the LED would be very useful for the start counter.

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+# Details: [http://www.jlab.org/Hall-D/software/wiki/index.php/Dec_06%2C_2010_Calibration/Monitoring Minutes/notes from December 6, 2010]
 # Comment: Time (and temperature) stability most important.
-# Comment: Option of delivering a range of light intensities important (e.g. using various filter settings).
+# Comment: Option of delivering a range of light intensities important (e.g. using various filter settings). Athens: test stability of LEDs at low output (near threshold) to see if this can be used as an additional check point in our monitoring.
-# 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.
+# Comment: The flexibility in the use of the LED would be very useful for the start counter.
-# 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  [http://physics.indiana.edu/~ptsmith/pulseled/ LED pulser by Paul Smith] which might be a useful reference.