2017 TOF Low-Level Plots¶
This is a short summary of plots which have been checked for anything suspicious.
Only a few (18) runs from all the user cycles in 2017 were selected. Plots for all selected runs (listed below) are tar-balled in tof_plots.tar.gz (in pdf).
A description of each plot for example run 10428 follows after the run-list table.
In summary, no obvious deviations have been observed in the selected runs, except for inefficient space point reconstruction in some runs due to improper calibration of outer slabs.List of runs:
Distribution of TOF PMT hits. This is a simple check whether all channels are operating.
Hit distribution among PMTs is separated for each plane (plane 0
@ top, plane 1 @ bottom) of each TOF (TOF0, TOF1, and TOF2 from left to right).
PMT hit times¶
Distributions of recorded PMT hit times. The distributions are flat which I presume is expected. The hits should be localised in time relative to trigger hit TDC.
PMT hit charge¶
Distributions of recorded ADC of all PMT hits. The shape of the distribution changes from run to run. This may be due to differing beamlines which then gives different weight to individual PMTs. Each PMT should be expected to have different response. I have not checked charge distributions for individual PMTs.
Check if there are inefficient slabs.
N slab hits / N PMT hits¶
Ratio of number of reconstructed slab hits to the number of recorded hits for each plane. In perfect case, there are always two PMT hits creating 1 slab hit (ratio = 0.5). Events with lower ratio show that there are PMT hits which don't have a matching hit in the opposite PMT.
N space points / N slab hits¶
Ratio of number of reconstructed space points to the number of reconstructed slab hits. Ideally, a particle creates 2 slab hits (1 in each plane) and 1 space point is reconstructed (ratio = 0.5). Events with ratio greater than 0.5 are due to the ambiguity when there are more slab hits with times within 0.5 ns.
Inefficient Space Points Reconstruction¶
Cases where there were at least 2 slab hits, one per each plane, but no space point was reconstructed were also investigated. Big part of such reconstruction inefficiency is due to the used cut of 0.5 ns on their hit-time difference. Hits with times in the tails of the hit-time distribution are cut off.
For some runs, outer slabs of TOF2 were not properly calibrated, rendering space-point reconstruction impossible.
Slab hit times¶
Distribution of reconstructed slab hit times for events with 2 hit slabs but no space point reconstructed. The same distribution but for events with 2 slab hits and 1 space point reconstructed is overlaid in red for reference.
Detail of reconstructed hit times within +/- 1 us from trigger time.
Slab hit charge¶
The same distribution but for events with 2 slab hits and 1 space point reconstructed is overlaid in red for reference.
Slab hit X-Y distribution¶
2D distribution of the pairs of slab hits for which no space point was reconstructed. For reference, the same distributions are plotted at the bottom for events with 1 reconstructed space point.