Postscript files containing the EMC OEP plots are produced automatically from the hbook file generated by FastMonitoring in IR2. The directory containing the most recent OEP plots is here.

For each page, reference plots are shown for "normal" conditions, and for some known problems. I will try to describe what is shown on each plot, the reason the plot looks as it does, and what the EMC expert shifter should look for.

The first page is a brief summary of some of the most important plots from the other pages. I won't go into details here.

PAGE 2 - digi timing

If there is a noisy crystal which is constantly reading out a given energy, this will sometimes show up on this plot as a horizontal line, such as can be seen here. Occasionally, a 'blob' can be seen beside the peak, such as here. This is usually correlated with high backgrounds. Both these occurences are worth noting in the shift report.

The bottom plot on page 2 is the time distribution of digis that pass a 5MeV energy cut. There is an attempt here to fit the digi timing plot with a Gaussian function (although this function clearly does not describe the whole distribution very well!). The mean position of the Gaussian should be between 6300 and 6400.

PAGE 3 - digi timing per trigger line

It is noticable on these plots that the timing peak is slightly sharper in the EMT only lines (as we would expect, since the trigger decision is based on EMC information), and that the peak goes to higher values of energy for the 2E and EMstar plots, because these are mainly bhabha events.

Normally there is not much that the EMC shifter needs to look at in these plots.

PAGES 4 and 5 - digi multiplicity vs event number

In smooth data taking, with trickle injection in both the LER and HER beams, these plots should be approximately flat, as the beam currents and luminosity remain constant. If trickle injection is not working in one or both beams, the plots may show a slight downward slope as the luminosity slowly decreases over the course of the run. Sometimes when refilling the beams after a beam loss, these plots may show a slight upward trend at the start of a run, as PEP declare "stable beams" (and therefore data taking begins) before the beam currents have reached their maximum values, and current is trickle-injected at a high rate to "top-up" the beams. Backgrounds may be expected to be slightly worse in such situations.

Sometimes a spike such as in the top plot here can be seen. Often this occurs at the very end of the run, when the beam was dumped. If it occurs in the middle of a run, it could be something like a trapped event(??). The shifter needn't worry about things like this.

PAGE 6 - noisy channels

Page 6 shows the noisy channel map. The x-axis is the theta index and the y-axis is the phi index of the crystals. We normally expect this plot to be empty. If there is a noisy crystal, or a group of them, you should try and note the theta and phi indices of the noisy crystals, and send an email to babaremc so that these channels can be masked out (and note in your shift report).

PAGE 7 - dead channels

Page 7 is also a map of all the crystals in the calorimeter. Here, any crystal that has at least 1 hit during the run is coloured blue, so any white holes are dead crystals. These might be intentionally masked out because they are noisy, or they may be dead due to a problem with the Front End Electronics (FEE). A small hole is a single crystal. Four crystals next to each other in theta represent a "CARE" chip. Three CARE chips next to each other in phi represent an "ADB" (12 channels). Two ADBs next to each other in theta represent a "fibre" (i.e. 24 channels). Three fibres next to each other in theta represent an "IOB" (72 channels). If you see a new dead region, send an email to babaremc and note it in your shift report.

In the plot above, there is one CARE chip masked out at theta=53-56, phi=21, and four individual dead channels, giving a total of 8 dead channels.

PAGE 8 - Hitmaps

Page 8 shows four hitmaps, each of which has the theta indices of the crystals on the x-axis and the phi indices on the y-axis. The difference between these plots and the map on page 7 is that here the colour of each bin represents how often that crystal was hit during the run.

The top left plot shows all the digis (hits in crystals) in every event. The top right plot shows all digis that pass a 10MeV energy cut. This gets rid of the electronics noise, so these are hits that have a good chance of being used to reconstruct clusters. (Note, this is the plot shown on the summary page, and also the main one that the DQM shifter looks at). There is often an excess of hits extending from the left of the plot (the forward endcap) to the region around theta=20, phi=60. This is background from the High Energy Ring (HER). The bottom left plot has a digi energy cut of 100MeV, while the bottom right plot has a 1 GeV digi energy cut. The statistics are therefore much lower here, and for short runs there will often be large unfilled regions, particularly in the middle of the barrel.

The reference plots above demonstrate several interesting features:
The "no cuts" plot on the top left has two noisy crystals around theta=25, phi=39. Features such as this are relatively common, and since these crystals are only giving hits at low energy (they don't show up on the other hitmaps), we don't worry about them too much (though it's possible they could slightly degrade the energy resolution of clusters in that region).
The "10MeV" hitmap on the top right shows 3 slightly warm crystals in the middle of the barrel, and, more significantly, a warm CARE chip at theta=53-56, phi=21. This is worth noting in the shift report (if it persists over many runs, you could just write a general comment such as "Most runs contain a noisy CARE chip in 10MeV hitmap at theta=53-56, phi=21").
The "100MeV" hitmap on the bottom left has several quiet crystals. Features like this are quite common, and are not fully understood. These are not usually noted in the shift reports.
The "1GeV" hitmap on the bottom right also has several crystals with zero hits at this energy. There is also a warm CARE chip visible at theta=36-40, phi=110. This is worth noting in the shift report, so that the electronics experts can decide whether it is necessary to mask it out.

PAGE 9 - Projections of hitmaps

Page 9 shows the projections of the hitmaps on the previous page in theta (top) and phi (bottom). The left hand plots have a digi energy cut of 10MeV (so these are projections of the top right plot on page 8) and the right hand plots have a 100MeV digi energy cut (bottom left plot on p8).

The theta projections show more hits at the far forward and backward ends. The phi projections have more hits in the region from 40-80. Note that the steps in the distribution at phi=80 and phi=100 are due to the geometry of the endcap: the first 2 rings in theta only contain 80 crystals, while the next 3 contain 100, and all the rest of the rings contain 120 crystals.
In the reference plots above, the noisy CARE chip that was visible in the 10MeV hitmap on page 8 is also visible as a spike at phi=21 on the bottom left plot.
If the HER background is worse than usual, the left hand plots might look something like they do here .

PAGE 10 - Digi multiplicities

Page 10 shows the distributions of number of digis per event, with different cuts on the digi energy. The top left plot has no energy cut, and should look something like the reference above. The mean of the distribution is usually in the range 830-860, but may be higher if there are bad backgrounds. Sometimes bad background conditions can show up as a secondary peak in this distribution, such as here . Or in some cases, there are even a lot of events containing more than 6000 digis (essentially all the crystals), such as here . This type of very high digi multiplicity event is often associated with trickle injection. Unusual features such as these are worth noting in the shift report.

For the top right plot, the mean of the distribution should be around 30 or just below, and there should not be many entries going above 120 digis or so. If there are high backgrounds, the tail of the distribution may be much longer, and the mean higher, like this .

PAGE 11 - Digi energy

Page 11 is a histogram showing the energy (or log(E)) of all digis, and should look something like the reference above. The y-axis is on a log scale, so there are clearly many more digis with low energies (around 1 MeV).

PAGE 12 - Energy profiles in theta and phi

The top plot on page shows the average energy of a digi as a function of theta. The average digi energy is higher in the forward and backward ends. The bottom plot shows average digi energy as a function of phi. There are peaks at phi values around 30 and 90, which correspond to the vertical plane. If the average digi energy is lower in some runs, or in a particular region of the detector, this may be because there are more background hits (which tend to be lower energy).

PAGE 13 - Event and Emc TC Damage

The bottom plot on page 13 shows the fraction of events containing different types of dataflow damage. It is not unusual for this plot to look something like the reference above. The most common types of damage are in bins 12 and 13 - OutOfOrder and OutOfSynch. If these occur at a frequency greater than 0.5 percent, it is worth sending an email to babaremc.

PAGE 14 - Emc TC Damage vs ROM

This plot shows the various types of TC damage on the y-axis, against the number of the ReadOut Module (ROM) where the damage came from on the x-axis. There are 100 ROMs in total, arranged into 10 crates. If there is a lot of TC damage in an event (as can be seen from page 13), it is often useful for the EMC experts to know which ROM the damage was in. For example, in the plot above there was some OutOfOrder and FLINK_TimeOut damage in crate 0 slot 4, and a higher level of damage in crate 0 slot 7. Meanwhile, in this plot, there was TC damage (OutOfOrder, OutOfSynch, FLINK TimeOuts) from all ROMs in crate 3.
If the amount of damage (as seen on page 13) is significant, (say, greater than about 10^-3) information about which ROMs the damage is coming from is worth including in the shift report.
If the same ROM consistently shows TC damage (even at a low rate such as 0.1%) it might be worth bringing this to the attention of the experts in the monday EMC operations meeting.

PAGE 15 - Emc TC Damage by Fiber

Page 15 is the same, except that the damage is further subdivided into fibres - each ROM has three fibres carrying information from the Front End Electronics. If a problem shows up in one fibre but not the other two, this is worth noting in the shift report.

PAGES 16-18 - Channel Maps

Pages 16, 17 and 18 contain essentially the same information as the hit channel map on page 7, but in some plots this is laid out differently to make it easier for the electronics experts to isolate which piece of hardware is at fault. The EMC shifter doesn't need to worry about this.

PAGES 19-23 - Energy profiles

The next 5 pages show the average energy of digis in each crystal vs the channel number of that crystal. There are 720 channels in each of the 8 crates in the barrel (crates 0-7), and 410 channels in the endcap crates, which is why there are some gaps in the plots for crates 8 and 9. The 'saw-tooth' pattern in these plots is due to the way the channels are numbered sequentially in theta within each IOB (72 channels), so that higher numbered channels are located in regions that are hit by higher energy photons. If a particular bit of hardware (e.g. a CARE chip (=4 channels)) is behaving strangely, such as always giving out high energy hits, or not giving out low energy hits, this might show up as a spike in one of these distributions, such as can be seen in crate 7 here. This is worth noting in the shift report.