How to use XED: Quick Start

Here is a SNOMAN command file that invokes XED to look at ZDAB data files:

* Command file for use with XED viewer module

file inp 1 my_zdab_file.zdab

define event_loop
        call inp
        call upk  * Unpack
        call cal  * Calibrate
        call ftt  * Fit
        call xed  * View the event
end_def

@run_snodb

This command file does just as it advertises: it loads each ZDAB in turn, unpacks, calibrates, fits with the time fitter, and then passes the event to the viewer.

XED will do nothing until it executed for the first time. It will then write a few standard startup messages to the standard output, and put up an Event Display window, which usually shows the PSUP in 3d.

The execution of SNOMAN processing now pauses. SNOMAN will process no more events until the user requests the next event, at which point the next call is made to INP.

Most, but not all, of the interface in XED is identical to that in the stand-alone XSnoed application. The documentation for XSnoed is available at

http://manhattan.sno.laurentian.ca/xsnoed/xsnoed.html,

and can be loaded automatically from the ``User Guide...'' command in the File menu. For those unfamiliar with XSnoed, read the section 4.0.8 on XSnoed basics.

The XED main window is much like the XSnoed stand-alone main window, with a few notable exceptions. First, if the window is closed (by clicking on the close box of the window), XED will close down the window. At this point, SNOMAN will start processing all events, simply skipping the XED call on every event. The same effect is achieved by choosing 'Close Display' from the File Menu.

To quit SNOMAN entirely, chose 'Quit Snoman' from the File menu. This stops all program execution (by a call to ZEND). Input and output files will be closed, DARN files and hbook files will be saved, etc.

Event navigation is different in XED than in stand-alone XSnoed. The Event Control Window is gone, and is replaced by the Snoman Control Window.

Figure 4.1: The Snoman Control Window in XED

The top line of this window shows the current status of the viewer. At first startup, it should read 'Viewing the current event'. This means that an event has been successfully loaded from SNOMAN and is being shown by the display.

To see the next event, there are two buttons: 'Next/Pass' and 'Next/Fail'. These buttons are equivalent in this example. (See the section 4.0.3). Both buttons pass control back to SNOMAN to process the next event. When clicked, the status bar will show 'SNOMAN is working...' to indicate that the next event is being loaded. During this time, the event display will be completely frozen, an unfortunate side effect. (In future, the viewer may be adapted run as a separate thread or fork to avoid this.) In most cases, this delay should be short.

Also in this window are the familiar -1 -10 +1 +10 buttons for event navigation, but the +1/+10 buttons should be grayed-out and inoperable. Because XED cannot rewind ZDAB files but is dependent on SNOMAN to supply the data, there is no skip-ahead function. However, one can press the -1 (-10) button to view the last (tenth last) event.

When viewing, say, the previous event, the text next to the +- buttons will read 'History: (-1)', and the status line will change to read 'Viewing an event in the history buffer...'. This feedback is to indicate that the event being shown in the display window is NOT the event the SNOMAN is currently working on, but is rather an event buffered only in XED memory, and is therefore invisible to all other processors. When viewing an event in this buffer, the +1/+10 buttons can be used to move forward through the buffer, but the 'Next/Pass' and 'Next/Fail' buttons should be grayed out to show that you are not advancing SNOMAN.

Also shown in this window is the DARN/DAMN bank access, which is described in section 4.0.5.

The File Menu has commands for 'Next Event' and 'Prev Event', but the use of these is not recommended. They should operate much the same as the buttons, but care must be taken when using XED as a filter (section 4.0.3).

At the bottom of this window are Save File buttons, much the same as exist in XSnoed, and work in an identical fashion. Typing in a file name and pressing a save button will save the currently-displayed event into a ZDAB file. Note that SNOMAN knows nothing of this file, and it is not recommended for any official analysis: the resulting ZDAB file has no permanent banks (e.g. run header, calibration information, etc) but is useful if you want to be able to have fast access to a particular interesting events.

subsectionWhat XED Shows

XED works by looting and pillaging the SNOMAN data structure and passing what it learns on to the viewer. Here is a list of the information that the viewer can show.

• Event Info. XED will show the ZDAB event header in the Event Info window. Tube counts (e.g. Neck tubes) are as computed by XSnoed, not SNOMAN.

• Raw data. XED can show the uncalibrated PMT data of TAC, Qhs, Qhl, and Qlx, by selecting the 'Uncalibrated' option in the Data menu.

• XSnoed Calibrated Data. XSnoed has a calibration option, mainly good for looking at data where no official calibration is yet available. Selecting 'Calibrated' or 'Cal No Walk' from the Data menu shows this UNOFFICIAL calibrated PMT data.

• SNOMAN Calibrated Data. If calibrations are available (i.e. the CAL processor has been run successfully on the event), the 'Official Calibration' option will allow the viewer to show Time and Charges of the PMTs. Shown are the PMTT, PMTHS, PMTHL, and PMTLX words from the PMT banks.

• Fitter Data. If a fitter has been applied to the data, the Fitter Window will display some information extracted from the FTx, FTxV, and FTxT banks for that fitter. If multiple fitters have been run, one can see all the entries by clicking the 'Next Fit' button. The currently-shown fitter can also be seen in the 3d view: the red dot shows the fit vertex, the line shows the fit direction. The red circle projected on the PSUP in both the 3d and 2d view windows shows the projection of a Cherenkov cone onto the sphere given the fit direction and position.

• Monte Carlo Vertices. Any existing MCVX banks are shown as points in the viewer. Bringing up the Monte Carlo window allows control of which vertices are are shown. Bringing the cursor over a particular vertex will highlight it on the display and in the Monte Carlo window.

• Permanent Bank Data. If a permanent bank is read by the INP processor, a copy of the bank is stored by XSnoed and can be seen by looking at the Run Header window. Several different Permanent banks are supported in this way, including RHDR (Run Header), TRIG (Trigger settings), EPED (Pedestal), SOSL(Laserball run data), and CAST(Calibration source) banks.

• Data Masks. The Snoman Control Window can show the bit settings for any DAMN or DARN bank currently loaded. Enter '0' in the 'DMM Mask Number' field to see DAMN bank bits, or any number greater than 0 to see the corresponding DARN bank. This is described in greater detail in section 4.0.5.