The Liaison Shift Manual

This manual is no longer updated! Please go to the new documentation at /BFROOT/www/Detector/Backgrounds/liaisons/manual/. Please update your links, bookmarks etc.!

This manual can be found at /BFROOT/www/Detector/Backgrounds/liaisons/shift_manual.html .



 
Lifesavers Our Homepage Our Hypernews Useful Phone Numbers Getting Started Computing
Responsibilities  Log Books Background sensors SVTRAD Tips&Tricks DCH and EMC Diode Info Shift Duties
Tools Using SCP Strip Charts MCC Error Log EPICS Information :-) 


What's New


Useful Phone Numbers




Idiot's Guide to Starting a Shift

See Shift Duties for things to be done on every shift. Before each shift starts, stop by IR2 and talk to the shift leader to see what the plans are for the next shift, if there are any current problems, etc.

When your shift starts at MCC, introduce yourself to the EOIC, the engineer operator in charge. This person is the "shift leader" at MCC. S/he does the minute to minute decision making. The program deputy is in charge of making major program for the day type of decisions, who gets beam, etc. Be nice to these people, they are in charge of what's going on down there.

Don't talk to random people at IR2, talk to the shift leader. Keep the lines of communication open. It can be frustrating to sit down at IR2 with no clue about what is going on with the accelerator. In particular, let the shift leader know if there will be any beam off periods of more than an hour. BBR can use this time for calibration, cosmics and other detector tasks.

You must be a member of the hypernews forum in order to write to the electronic logbook and in order to be an effective member of the liaison team. If you have not already registered, please go to the hypernews page and become a member. Do it now. Many liaison shifters have yet to become members.

The general idea is that you will be running two session managers, one on bbr-con13 for BaBar related things, and one on the MCC VAX for a SCP. You will notice that many tasks have a certain duality. There are BBR EPICS variables which come from the BaBar EPICS system and there are MCC EPICS variables which you can access from the SCP panels. This will no doubt generate some confusion at first, but hopefully we'll all catch on soon.

If the set of liaison shift windows is not already in place when you arrive or there is some other problem with the terminal, you should execute the following procedure step by step to start from scratch:

Careful execution of the above steps in the described order should get you back into business. Here are a few more tips for comfortable working:




Computing Information

Our general login computer will be bbr-con13 or bbr-con14. If those are down, contact Tom Pavel. If you cannot contact him, call the BBR shift leader. If necessary, use bbr-con01 or bbr-con02. These computers are on the ir2 subnet.

You are using the MCCX6-BBR xterm.

Changing the Window Manager on an MCC X-terminal

(This and the next several section have been written by Alexandre (Sasha) Telnov. Last update: May 15, 1999.)

Introduction

Work of a shifter involves having to deal with dozens of X windows in an efficient manner. IR-2 shifters have the luxury of having at their disposal quite a few console machines with a total of 16 monitors that run a state-of-the-art operating system (Solaris 2.6) with a state-of-the-art window manager (the Common Desktop Environment, CDE). A BaBar/PEP-II liaison, on the other hand, is limited to one X-terminal running rather obsolete OpenVMS/DECwindows.

The DEC window manager is limited to one logical desktop the size of the screen. Various window managers from the UNIX world feature either a virtual desktop that has a size of several physical screens (for example, tvtwm), or multiple logical desktops (for example, CDE). They allow the operator to spead windows across a larger area and group them by function, which can significantly enchance operator's productivity.

One can change the default X-window manager by killing the current WM process and then starting a new window manager, which, by the way, does not have to run on the same machine. Unfortunately, due to incompatibilities between UNIX X-libraries and the DEC's X-server, the only advanced window manager that we have been able to successfully run at the MCC is the twm-based ctwm. Here is how you can start one:

Killing the DECwindows window manager and starting ctwm

  1. If this has not already been done, log into the OpenVMS node MCC from any of the MCC X-terminals as user MCCSCP. DECwindows will start and several application windows (SCP, etc.) will be launched.
  2. From the NCD console, telnet to bbr-con13 and login as user babarpep. Unless something is wrong, $DISPLAY will be set to the right value automatically and bbr-con13 will have access rights to your X-terminal. You can verify whether this is the case by trying to launch a simple X-application, for example, xlogo.
  3. Go to the "Session" -> "Work in Progress" menu in the DECwindows Session Manager. The "Work in Progress" window should contain only one entry: the current window manager. Do not do anything to it just yet.
  4. In the bbr-con13 window, type sleep 15; ctwm & and press "Return". This will make bbr-con13 start ctwm after a 15-second delay. You now have 15 seconds to go back to the "Work in Progress" window and Stop (i.e. kill) the current window manager. That's it!

ctwm tips

ctwm has look and feel of twm, one of the two granddaddies of most X-window managers. It is markedly different from CDE and fvwm, which are based on mwm. But don't worry - you will get used to it soon. Here are some tips and tricks that you should know: A special note about EPICS windows: ctwm and other multiworkplace window managers require that an application's main window and all of its daughter windows be located on the same workplace. This means that you cannot move EPICS windows (other than the top-level dm window) from one workplace to another. There is, however, an easy way to circumvent this restriction: apply "Occupy All" to the "Online Detector Control Main" window and keep it iconized in a corner of the screen. Now, when you need to open a bunch of EPICS windows (all of which inherit from the "ODC Main" window, you can do it in any of the available workplaces. Since the "ODC Main" window is now occupying all workplaces, you can open EPICS windows in any one (or several) of them without violating the above restriction.

I hope you enjoy using this window manager. Please let me know if you have any questions or suggestions.

What to do if your Window Manager dies

Although this happens extremely rarely, it is useful to know that it is usually possible to revive your session without losing any windows. The recovery process is particularly simple if you are using an X-terminal (as opposed to a UNIX workstation).

You know that your window manager has just died if your screen suddenly fills with all windows, including those that have been iconized, and neither of them has a frame. To recover, do the following:

  1. Press Alt-F3. The NCD X-terminal console will appear. Go to the WindowMgr menu and choose the NCD Window Manager. A turquoise frame will appear around each window.
  2. Go to a window with a bbr-con13 session and execute sleep 15; ctwm & .
  3. Within the next 15 seconds, go back to the NCD console window and stop the NCD Window Manager by unchecking the box next to its name. ctwm will restart shortly.
  4. Get rid of the NCD console window by going to Console and Close. Be careful and do not click on "Reboot"!

Using XV to capture and print windows

XV version 3.10a can be used to capture, save and print windows of appications that do not have a functional printing facility. The variable delay before the capture mode is activated, the ability to capture an arbitrary rectangular area of the screen, and the ability to save the pictures on disk in a variety of formats, including PostScript, make XV a superior alternative to the xwd/xwud/xpr utilities envoked by StripTool and other applications.

To start XV, type XV (capital letters!) in a bbr-con13 window (at the moment, we have the latest version of XV installed only for user babarpep in /var/babar/xv/bin on bbr-con13). To get the XV controls window, right-click anywhere in its main window. To capture a window, choose Grab and select the grab delay time, which lets you locate the window you want to capture. (Tip: In ctwm, you can use Alt + Left mouse button to pop up a window controls menu. Choosing FullZoom lets you resize the window to fill the whole screen; repeating FullZoom restores the window to its original size). You will hear a beep when XV goes into the capture mode. The rest is easy and intuitive. Let me know if you have any questions or suggestions.

talk'ing to IR-2

The talk utility provides a way for the BaBar/PEP-II liaison and the IR-2 shift leader to exchange textual messages, which is oftentimes more convenient than calling IR-2 on the phone. In the beginning of the shift, the liaison and the shift leader should each start an xterm under their own accounts, for example,

ssh bbr-con13 -f xterm -g 80x60 -T TALK -sb -sl 1500

It is useful to have xterms of equal sizes; 80x60 works fine in most cases. The next step is to establish a talk connection, talk babarsl@bbr-con02. The other side has to reciprocate with talk babarpep@bbr-con13. After a [connection established] message appears, everything you type in your talk window will appear in the talk window of the IR-2 shift leader.

(Tip: Hitting Control-G will make the computer on the other side beep. Doing it a few times will surely attract attention of the person on the other end.

What to do if your X-terminal does not beep

If your X-terminal does not beep when it is supposed to, go to Session Manager -> Options -> Keyboard and adjust the bell volume.

Rebooting the liaison X-terminal

If the X-terminal must be rebooted for any reason, use the following procedure to boot it: power it down and, after a dozen or so seconds, power it up. If it gets stuck trying to determine its IP address, press F11 and type at the boot monitor prompt:

bt Xncd19c_s 134.79.156.95 134.79.17.14 134.79.159.1 255.255.252.0



The electronic logbook

There are several communication paths for the liaisons. The liaison hypernews is the official method for detailed, technical discussion among liaison shifters. In addition, there is an old-fashioned written logbook at MCC since sometimes writing notes to each other is the most effective method of communication. However, our primary electronic logbook will be the BaBar electronic logbook. The electronic logbook is an oracle/web based logbook. You must be a member of the hypernews to access this logbook.

The logbook is form/field-based and should be somewhat self-explanatory. Liaisons are treated like a subsystem, so we have our own little page with fields for "General Notes," "Activities," "Problems," and "Other Notes." It is sometimes difficult to decide if an event is an activity or a problem, so some people just write everything under "Activities." It doesn't really matter where you write your notes, but be sure to click on "Update" or "Commit Changes" whenever you make an entry! The Babar shift leader is responsible for starting a new entry for each shift. Do not do it yourself.

If the logbook is not already going when you arrive, start Netscape by typing setdispmcc and NETSCAPE (rather than "netscape"). This starts Netscape so that it doesn't hog the colormap and cause later problems to EPICS. Then click on the bookmark for the logbook. Enter your hypernews userid and password when it asks for it.



EPICS Information

If EPICS is not already started when you arrive, type startepics. If there are problems, exit any Netscapes as well as any other programs using colours (such as xv, SCP) and try again.

If you accidently exit EPICS, restart epics by typing BaBarMain . Again, if there are problems, exit any Netscapes or other motley colourful programs and try again.
If BaBarMain gives you a Command not found and startepics tells you that you have already source'd the startup file and that there would be nothing new to do, then it's probably because your AFS token has expired. Try a klog or, if that does not help log out and in again.

General info on EPICS navigation can be found via this link.

When you start EPICS, the first window brought up is the Online Detector Control Main. Some useful EPICS pages are (click on the EPICS button names which are in bold face):

SVT EPICS Information:

EMC EPICS Information:

BaBar Run Control: PRINTING: Mouse buttons and EPICS: Color scheme in EPICS: WARNING: If an EPICS window is occluded by other windows on the xterm, clicking on an active part of the window (e.g., a button) when clicking to bring the EPICS window to the top, executes the action. Be careful where you click in an EPICS window.




Be an SVTRAD Power User! Read on:

[ Overview | Diode Dose Rate Calibration | ABORT Threshold Re-calibration ]

[ SVTRAD Troubleshooting | FastHistory Buffer | Tools ]

The SVTRAD system has been designed to protect the SVT and monitor the radiation dose delivered to the Silicon and the front-end electronics. the entire system spans hardware, firmware, CANbus, EPICS fotware, and even a schmattering of UNIX sheel scripts and PERL programs, and numerous web-based support pages. It is a monster protecting a very delicate jewel at the heart of BaBar.

As TheLiaison, you need to be aware of the most delicate and valuable part of BaBar, the SVT, and its fairly sophisticated active protection mechanism, the SVTRAD system. As a Liaison, you should be aware of the following types of issues and controls:

  1. So-called NO BEAM calibration of the 12 SVT diodes' strip chart signals (the instantaneous dose rates). This calibration is now performed by the Liaison, and takes 30 seconds.
  2. The calibration of the ABORT thresholds for the SVT abort diodes; this takes into account the radiation damage delivered to the diodes, and erodes the abort threshold at a rate of 10-15% per day of high LUMI running. TheLiaison can now perform this exciting task at the press of an EPICS button. (Hooray! No screwdrivers!)
  3. The SVTRAD system has a post-mortem fast history buffer that is dumped to disk each time a module trips. Read on to learn how to make the best use of it.
  4. SVTRAD can dump the beam via a front-end ABORT circuit decision, and now most recently, based on an several minute EPICS software decision, the so-called "Soft Abort."
For most of the work here, you'll want to familiarize yourself with the SVT Background EPICS panel. See the EPICS help file for a good introduction.

SVTRAD Features

The SVTRAD system uses BaBar EPICS to show you which diodes caused a radiation trip, provide real-time dose rates for the 12 diodes, and allow the user to calibrate the system. Strip charts of dose dose rates are available from SVT-BaBar EPICS, under BaBar Main --> SVT --> Background. Right click and drag down a menu from History Plots to choose the plots that you'd like. The total integrated doses for the diodes are available as the final entry in the plot menu.

SVTRAD MONitoring Calibration

The NO BEAM calibration for the online MONitoring (stripcharts) should be done at least once per shift, and takes about 30 seconds. The autoDetect system, when enabled, will perform periodic SVT diode dose rate calibrations automatically, whenever suitable NO BEAM conditions are detected by BBR EPICS. This new system replaces the need to calibrate the SVT diodes (strip-chart signals) by hand. There is a traditional EPICS panel interface, available off the SVT-->Background==>Expert Controls (right click and drag) Calibrate Diode Dose Rates --> autoDetect

For some additional information about the autoDetect system, please see the sketch of plans. Some general comments are gathered here, and you must know about them:

The new panel looks something like this:

To do the SVT diode dose rate calibration by hand, execute the following steps. If you'd like to check on when the most recent SVT diode dose rate calibration was done, use this panel, too.

  1. Wait for a moment of zero beam, perhaps right after a beam abort, but be sure that the FastBuffer has finished writing to disk.
  2. Then choose SVT --> Background --> Expert Controls (right click and drag) ==> Calibrate Dose Rates from BBR EPICS. You'll see this:

  3. If you want to check on when the last few SVT diode dose rate calibrations occurred, click on the grey Lookup Recent Dose Rate Calib button. An xterm window will pop open in a few moments listing the times of the last few calibrations for TODAY. Each line lists the time, the action ("FIT"), the leakage current for a particular diode, and two error quantization parameters. (IGNORE THESE!!)
  4. Click NO BEAM. You should see the StripChart signals converge toward 0 mR/s.
  5. After about 30 seconds or 15 points in the fit (see indicator on the panel), click back to the UNKNOWN state.
  6. Congratulations! You have NO BEAM calibrated the SVT diodes. You should make a note in the E-LOGBOOK that you have done so.
  7. If you'd like a quick measure of how much the dose rate pedestals were "corrected" by the calibration, click on the Pedestal Corrections button on the panel; it will launch a new panel telling you roughly how much the pedestal shifted as a result of the calibration.

SVTRAD ABORT Threshold Calibration

This calibration is essential on a daily basis when we are doing high current and/or high LUMI running. A good day of data will deliver enough radiation to the ABORT diodes to erode the threshold by 10-20% due to radiation damage.

This is a mandated daily ZERO BEAM calibration time for BaBar EVERY single calendar day. This usually occurs during the first half of day shift, so it is nominally the day shift's responsibility to see to it that during the BaBar calibration period of 5-10 minutes, the SVT ABORT diode threshold get adjusted for radiation damage. This process is easy to do -- it requires one button click in EPICS, but knowing what you are doing never hurts. One may always use the UNIX script directly, but the EPICS panel has been revised and now offers some user-friendly feedback. The UNIX script has been modified to allow different thresholds for different diodes. A Liaison-friendly algorithm to SET these thresholds from UNIX is not yet installed. Currently the Liaison can only re-calibrate/re-install the "existing" thresholds. Contact TIMeyer if you need to change the values of the thresholds. (The present method will involve Tim using caput, etc.)

If you're _changing_ the thresholds, you need to be in contact with Tim Meyer, the SVT Expert on call, and the Shift Leader.

To re-calibrate the SVT diode abort thresholds:

  1. Be sure the beams have been dumped, and that you have 3-5 minutes to complete this operation.
  2. Click on SVT.
  3. Click on Background.
  4. Right click and drag down a menu from Expert Controls.
  5. Select Calibrate ABORT Thresholds and release.
  6. This new panel will have just two buttons that are only active when the beam currents are consistent with 0 mA. Press the button for the thresholds that you'd like to install for the re-calibration (You will find the set you like on the Start Menu panel.)

  7. After 10 seconds, all 4 SVT MID plane diodes should register red ALM on the Background panel. The ABORTCalibrate panel should agree by setting the CFG_TRIP lights red. An xterm window should pop up and begin spewing information, and then pause. It print the status log of each of the 4 diode's calibration taksks when each is complete.
  8. After you see all four ABORT Calibration Complete messages in the xterm log-viewer, all of the CFG_TRIP lights should have turned green again. Hit CTRL-C to close the log viewer. Check that the new pedestal leakage measurements are plausible.
  9. The ABORT re-calibration taks has been adjusted to include a 35-second NO BEAM monitoring calibration AUOTMATICALLY after the abort threshold business ends. You no longer need to perform this task manually afterwards.
  10. You'll know the entire process is done when all 4 MID diodes are no longer in their active ALM state, and the xterm window tells you to Hit CTRL-C to exit this window, etc.

Common SVTRAD Troubleshooting

Yes, this system is fallible, and as usual, more fallible than its users. Here is a BRIEF listing of common errors and hints about what to do.

SVTRAD Fast History Buffer

This EPICS system is primarily useful to users who have some expertise with the abort system and the accelerator. It manages a "post-mortem" buffer for SVT radiation trips, and does not REQUIRE service from the liaison, but it sure will help us learn what is going on if we look at it regularly and look for patterns, etc.

The system will dump the contents of the SVTRAD module's fastHistory buffer to disk based on several trigger conditions.

The Liaison should select which trigger conditions are to be enabled during their shift, and then keep an eye on the modules. When a StripChart signal flatlines for a few minutes, or after an SVTRAD radiation trip, or after a "HER dust" event and if the system has been properly configured, a fastHistory buffer will be waiting on disk for Make Plots analysis.

SVT Diode Analysis Tools

The SVT radiation monitoring and protection system (SVTRAD) continuously logs information about instantaneous dose levels, integrated doses, and radiation trips in a set of ASCII text files archived directly by the svt-mon IOC. These files also contain information about the temperature near the diodes and the PEP-II beam currents. David Kirkby designed the original skeleton; T.I.Meyer (with some key assitance from Klara Elteto) has signficantly extended the machinery, and is now responsible for its management. The logfiles nominally live at /a/bbr-srv01/u1/babar/boot/iocs/svt-mon/log/bg/ and /a/bbr-srv01/u1/babar/boot/iocs/svt-mon/log/bg/archives/.

This document describes some of the basic tools that exist for analyzing these logfiles. We divide the tools groups into those that run automatically under babarsvt in IR-2 and update output files on a daily basis, and those that are provided for user-guided query and analysis. For a detailed picture of the entire SVTRAD system, please start at the SVTRAD online resource center, open 24-hours a day.

Automatically Updated

Every day between midnight and 1 o'clock A.M., several different jobs run under babarsvt's trscron daemon. The jobs collect, collate, and store several different types of information. The $HOME directory for these applications is /afs/slac.stanford.edu/g/babar/detector/svt/expert/diodes/.

For Specfic Use

This is a brief description of the toolset available. Many of these tools are used to produce the automatic reports above, but the expert user can form his/her own independent query/reporting jobs with this basic toolkit.




Everything you always wanted to know about the DCH and EMC diodes

Basics

Two sets of four silicon PIN diodes each are installed at the Drift Chamber front-end electronics and near the EMC end cap to monitor radiation levels in these delicate areas. Each diode is instrumented with a small block of CsI crystal for signal gain. The output currents of the four diodes of a given set are converted to voltages and then summed to one signal. The two signals (DCH and EMC) are connected to the BaBar input to the PEP-II beam abort system which triggers in case of radiation levels above a certain threshold. This provides effective protection of these detector areas from excessive radiation. The whole system was designed by Tom Mattison at SLAC, now at UBC Vancouver. It is called the analog protection system to distinguish it from the (much fancier) digital protection system of the SVT folks (SVTRAD).

When using diodes as radiation detectors one exploits the fact that a (reversely biased) diode's leakage (or dark) current varies linearly with the amount of radiation the diode is exposed to. This varying leakage current is sitting on a pedestal, the base leakage current present even in the absence of any radiation. (A new silicon PIN diode has a base leakage current of a few hundred picoamps.) See "Pedestal problem".

System experts

...or let's say the people you would call first.
DCH diodes (and EMC if Adrian is not around): Thomas Schietinger, ext. 2707, page 650-849-9521.
EMC diodes (and DCH if Thomas is not around): Adrian McKemey, ext. 4111, page 650-849-9107.

Liaison duties

The DCH and EMC diodes do not require much maintenance by the liaison. We would like you to do the following: Now have fun watching the signals go up and down! 

The pedestal problem

Unfortunately, the base leakage current of a diode is not constant, but depends on the temperature and the total amount of radiation the diode has accumulated during its life (its absorbed dose). Both effects were taken into account during the design of the system, but one was grossly underestimated, namely the radiation effect.

While the temperature changes turned out to be in the expected range, we had to learn during the first few months of running that the pedestal increase due to radiation appears to be about a hundred times faster than expected based on the experience of the SVT folks. Or there is something else pushing up that pedestal. However, based on radFET and TLD readings and the histories of the diode signals themselves, we can exclude the possibility that the pedestal rise is entirely due to ionizing radiation. To this day this is still a bit of a mistery, the leading theory is damage due to neutrons or/and slow protons.

Whatever is causing the growing pedestal it means that, instead of once at the beginning of a run as we expected, we have to readjust the offsets about a hundred times more often, that is every few days. Unlike the SVT PIN diode system, where large pedestal shifts were expected from the start, our system was not designed to provide a way to automatically recalibrate the offsets, it needs to be done manually with a screwdriver.

Who should reset the diode pedestals?

After realizing how often the pedestal would need readjustement we decided it would be a good idea to spread the knowledge among liaisons. Now that the liaison service is slowly being reduced, the next appropriate step is to familiarize BaBar shift leaders with this procedure. Therefore the answer to the above question is a) a system expert, b) the liaison on duty, c) the BaBar shift leader on duty, d) any human being that was instructed to do so by any of the above-mentioned people. (Clearly we don't want a situation in which anyone happening to pass by IR-2 quickly adjusts some pedestals just for some good karma.)

When should the diode pedestals be reset?

As a rule of thumb the pedestal needs adjustement whenever the signal without beam is more than about 30-40% of the threshold value above (or below) zero. The lower limit is somewhat "softer" in so far that we just relax the protection of our hardware by a little bit when going below it. In the other direction, MCC will quickly complain about injection inhibits if the pedestal approaches 50% of the threshold (by design, the system completely inhibts injection when the diode signal is above 70% of the abort threshold). For the values of the current threshold please refer to the EPICS BKG panel. Since March 2000 or so, the thresholds are set to 0.6 V (DCH) and 0.6 V (EMC).

More experienced users may want to look at the history of the diode signals over the last two or three days in SCP to get a feel for the diurnal fluctuations involved and take this into account when changing the offset.

How to reset the diode pedestals

Nine easy steps:
  1. Make sure you have a few minutes without beams or with very low current beams to perform this task. If you know the pedestal from a no-beam period of a few hours ago, and you are sure by how much you want to change them, you can actually do it during stored beams, but be careful to turn the screwdriver in the right direction!

  2. In any case it is a good idea to let the operators know that you will be doing something with the DCH and/or EMC signals.
  3. Get a digital voltmeter (may not be needed, see below) and a small screwdriver (a small Swiss army knife does the job just as well). We try to keep a screwdriver near the beam abort modules, but don't count on it!
  4. Go to the power supply alcove (Bldg. 624). This is the room across the IR-2 hall from the BaBar control room. You enter it via the short flight of stairs at that end of the hall, near the chiller forest.
  5. Locate rack B624-05 (in the third aisle). It contains an oscilloscope and a computer terminal.
  6. Underneath the oscilloscope and a patch panel you will find a CAMAC crate containing a bunch of black modules, "CAMAC beam abort modules", or CBAMs. The ones labeled "DCH" and "EMC" are the ones you are looking for.
  7. The trimpot (little screw) labeled "OFFSET" is where you want to adjust the pedestal once you know where to watch it. Note that the labels are above the things they label, so the offset trimpot is between the word "OFFSET" and the white horizontal line.
  8. Move the mouse of the terminal to reactivate the screen.
  9. We try to keep track of the pedestal changes in order to better understand them. Thus please note the changes you just made on the notepad lying around somewhere near the CAMACs. Thank you!
  10. Don't forget to go back to the control-room... and please don't forget to make a note in the electronic logbook either!

What about changing thresholds?

Under normal running conditions the thresholds must never be changed. And here's how to change the threshold, in case you really have to do it: In the top row of each CAMAC beam abort module, labeled "TOTAL" you have a lemo socket, a test point and a trim pot. The lemo cable transmits the diode signal to a SAM which makes it available in SCP. The trimpot changes the abort threshold voltage, and the testpoint is kept at that voltage. Therefore, in order to change the threshold, you would tweak the trimpot and check the voltage at the testpoint (relative to CAMAC ground). There may be a connector plugged into the testpoint. You can either temporarily remove the connector to measure the voltage or measure it directly at the metal part of the connector. Alternatively, if you don't have a voltmeter, but the stripchart on the terminal is running, you can load the channels PR02:ASTS:DCH_THR and/or PR02:ASTS:EMC_THR into the stripchart and adjust the threshold by checking the stripchart.

The nominal threshold values are currently 0.6 V for DCH and 0.6 V for EMC (March 2000). 


The background sensors

Information on background sensors can be found: Note that there are two parallel abort systems, the digital SVTRAD module and the analog abort module, denoted by CBAM (for Camac Beam Abort Module). There are both beam aborts, which will abort both beams when the radiation level gets too high, and injection inhibits which use a injection trigger information to determine if the high radiation is associated with injection and if so, will rate limit the injection.

BaBar Protection/Sensor Information from SCP (see Using SCP for more SCP info):



Using SCP

The main accelerator control system is SCP (SLC Control Program). By logging into MCCSCP, you will be starting a SCP automatically.

Once you have a SCP running, you can access BaBar information by clicking on "Babar Panel" and "Babar Analog Protection".

Warning: the SCP panels control the machine. DO NOT mindlessly hit buttons unless you know what you are doing.

General SCP Info:



History Buffers

Each of the variables in the MCC database is saved to an MCC history buffer approximately every six minutes (a few are saved more often). This information is very useful and can be easily accessed and plotted via the SCP.

Correlation Plots

A major use of the SCP is to run correlation plots. Correlation plots are a way to collect data from multiple variables over a certain length of time or while allowing a knob to vary over some limits. The data can then be plotted and saved for later analysis. This comes in particularly useful during machine experiments dedicated to backgrounds, e.g., beam steering, pressure studies, etc.

The correlation plots have two modes, data acquisition and data display. Near the top, in yellow print, the panel will indicate Correlation Plot DATA ACQ N1-N2 or Correlation Plot DISPLAY N1-N2. The N1-N2 indicate the variable numbers.

How to set up a correlation plot:

How to run a correlation plot versus time: Plotting the data: Saving the data: Message screen, errors, typos: Processing the data:

The correlation plot files can be "parsed" through a parser program (contributing authors: Tom Mattison, Geoffrey Pinski, Terry Geld). This is a Unix-based program which takes the nasty correlation plot data ASCII files and turns them into (i) kumac + data file so one can manipulate vectors with paw; (ii) ntuple; (iii) excel files with name and data stored separately. The parser area is: $BFROOT/detector/liaisons.

The help files can be found in $BFROOT/detector/liaisons/HELP.

the data files should be stored in $BFROOT/detector/liaisons/DATA/monYY, where monYY is the month and year.

There is a very nice GUI interface called xparse to make the liaison's life easier. Here is the help file for the xparse program.

All liaisons currently have the necessary access to the $BFROOT/detector/liaisons area, as does the babarpep account. Therefore, each liaison is encouraged to process the correlation plot files as soon as they are created.
 

Getting Error Reports

Beam dumps may sometimes be due to very fast radiation spikes that don't register in any of the history plots. You can find out what caused such an event by cliking on the BaBar Panel under the main SCP PEP-II index, then hunt around the various BaBar Protec panels, such as BaBar Protec Digitl.  The channel that caused the dump will be red, and can be reset by the reset button.



Using Strip Charts

A useful monitoring tool is the strip chart. Like the SCP/BBR-EPICS duality, there are two ways to start a strip chart, both using the program, StripTool. You can start a strip chart by going to the "BaBar Analog Protection" panel in a SCP as described above and then clicking on the "EPICS Strip Chart" button. This starts StripTool on an MCC Unix platform with access to MCC EPICS variable names. Alternately, you can start StripTool on a bbr unix platform (after the usual EPICS setup via startepics), typing StripTool &. From there, channel names and plot characteristics can be modified. It is possible to save and restore standard strip chart configurations.

Currently, there are these standard strip charts:

If you define a useful configuration, please add information about it here or let the person who is maintaining this manual know about it.

General StripTool Information

If some channels no longer appear on the strip chart, but are still readable in SCP, chances are that the channel access server (the EPICS interface to the MCC database) has a problem and needs to be resetted. Do the following: go to any MCC operator and friendly ask her/him the following question: "Could you please warm-slic the channel access server?" If the operator doesn't remember the command, remind him/her that it's warmslcx slccas/restart. (Note: you can tell whether the channel access server is up by looking at the main BaBar EPICS panel under BaBar/PEP-II CommLink and checking that PEP-II ACC is CONNECTED.)


The MCC Error Log

Beam abort incidents, injection inhibits as well as the resets (and tons of other stuff) are logged in the MCC error log. Sometimes it might be useful for the liaison to have a look at it to find out what exactly occured at which time. See also Getting Error Reports from SCP

You can do that from the OpenVMS node MCC (see Idiot Guide above) by typing ERRLOG. Then type HELP to learn more about the commands at your disposal. The most important ones are SET and LIST.

Here's a typical example:

MCC>ERRLOG
ERRLOG>HELP
... (carriage return to exit HELP)
ERRLOG>SET/SINCE=26-MAY-1999:12:30/BEFORE=27-MAY-1999:10:30
ERRLOG>SET/STRING=DCH_
ERRLOG>LIST

This will churn out all DCH incidents during the specified time period. Other choices for string might be

ERRLOG>SET/STRING=DCH_LABT

for all DCH LER aborts and resets, or

ERRLOG>SET/STRING="DCH_HABT,FAULT"

for all DCH HER aborts, or

ERRLOG>SET/MATCH=OR
ERRLOG>SET/STRING=(DCH_,EMC_,SVT_,SVT1,SVT2,BBR_,BBHV,DASY)

for all BaBar-related incidents. You can also do things like SET/DATE=YESTERDAY with obvious effect.
(I [Thomas S.] am still amidst discovering the beauty and joy of DCL scripting. I hope to be able to come up soon with a reasonable script liaisons could use without having to know clumsy VMS-like command names.)



Shift Duties

As part of the standard shift duties, each shifter should:



This is a work in progress. Please feel free to add info. It is not currently being maintained by anyone. A volunteer to do so would be very welcome.
Last modified: Sun Sep 26 21:57:34 PDT 1999