FPHX Prototype Testing Results


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For all results below, the plots show: channels that have produced hits (panel 1), number of hits recorded - number of hits thrown versus channel number (panel 2), ADC value of all hits (lower left panel), BCO of all of the hits (lower right panel). The BCO should be the same for all hits if the pulsing system and the FPHX are working properly. The same 4, 8, 16... channels should be hit for a given data set, and the same ADC value should be output for all hits since the pulser amplitude does not vary. The number of hits recorded - the number of hits thrown should be zero if the pulsing system and FPHX are working properly.

Found that the few BCO away from nominal occur in the first event primarily. So this appears to be just a start-up problem. For some events with a large number of hits/event, it seems like the beam clock moves away from nominal only after a certain number of events. This becomes less true as the number of hits/event gets larger.


Figure 1 Four channels pulsed once every 511 beam clocks, DAC amplitude of 100.



Figure 2 Four channels pulsed once every 255 beam clocks, DAC amplitude of 100.




Four channels pulsed once every 127 beam clocks, DAC amplitude of 100.


Figure 3 Eight channels pulsed once every 511 beam clocks, DAC amplitude of 100. Wrong BCO clocks are two clocks away from nominal.



Figure 4 Sixteen channels pulsed once every 511 beam clocks, DAC amplitude of 100. Wrong BCO clocks are three clocks away from nominal.



Figure 5 Thirty two channels pulsed once every 511 beam clocks, DAC amplitude of 100. Wrong BCO clocks are typically six clocks away from nominal.


Figure 5a Thirty two channels pulsed once every 511 beam clocks, DAC amplitude of 100. BCO of hits versus event number. As can be seen the BCO periodically jumps to 6 clocks away, but then returns to the correct clock number.



Figure 6 Sixty four channels pulsed once every 511 beam clocks, DAC amplitude of 100. Wrong BCO clocks tend to be 10 or 11 clocks away from nominal.



Figure 6a Channel ID of hits which have bad BCO number.



Figure 7 Four channels pulsed once every 511 beam clocks plus noisy channel 0 unmasked, DAC amplitude of 100. All data are shown here.


Figure 7 Four channels pulsed once every 511 beam clocks plus noisy channel 0 unmasked, DAC amplitude of 100. Channel 0 is filtered out of plots.

Last update by Melynda Brooks