Magnets Group Manual for the Experiment E89033

Table of Contents

• General Overview
• General Task List
• Field Setting Instructions
• Possible Problems and Their Solutions
• Magnet Settings during E89033
• References

General Overview

The HRS is composed of three superconducting quadrupole magnets Q1,Q2 and Q3 and one superconducting dipole magnet. A particle first traverses Q1 and Q2, then the dipole magnet and finally Q3.

Cryogenic information about each magnet as well as control interface for the power supplies is available on the control screen in Hall A counting house. You can get there from the startup display (described below). The power supplies themselves are located on the gantry adjacent to the magnets.

To run the control interface for magnets,

• Logon on the hac computer (account hacuser, password *****) and type HAC_hp if you are on HP machine or HAC_xt if you are on X terminal.
• Startup display will show up:

It summaries information about all the magnets. To get information on magnet power supplies, gaussmeters and NMRs click the corresponding buttons. From this screen you can also get some detector information screens.

To start an alarm handler for magnets type alh in hacuser home directory (that is where you start).

General Task List

The main task of the magnet operator is to be sure that the magnetic fields and currents in the spectrometers are correct at all times!

• Fill out run sheet and print magnet summary screen at the beginning of each run.
• Watch out for magnet power trips and communication software failures and try to fix it if it happens (see here). Call run corrdinator first if you have to get an access to the hall to reset a power supply.
• Change magnet settings when it is required. There will be two of them during the run time: first, for hydrogen kinematics and then, for oxygen kinematics. See here how to do it.
• Watch out for helium level and lead flow and call a Hall A technical support on-call if it would go low. See here for helium levels and lead flows limits for each magnet.
• Bring all the magnets down in case of a long interruption in data taking (e.g., during the maintanance days and/or some other major shutdowns).

Field Setting Instructions

Dipole Field Setting

To power up magnets:

• Go to the "Dipole Sytem" window ( electron or hadron);
• Push ON button and wait untill Power Supply will be ON and Magnet will be Engaged (it will take 2-3 minutes);

To set desired field do the following:

For the Electron Dipole:

• Go to the "Electron Arm Dipole Sytem" window;
• Type in desired value of current in Current Set (yellow field) and hit Return;
• Go to the "HRS Electron Dipole NMR" window;

Set the probe, make sure it has a right polarity; Set compensating coils voltage appropriately(if it was not set before), see writeup by J.LeRose; Put NMR in Manual mode; Type in DAC number for the field being measured, see writeup by J.LeRose ; Put NMR in {\bf AUTO} mode; Wait for desired current in Iout (about 20-30 minutes), in "Dipole System" window, and then for a lock in the NMR window("L" on the yellow background). If something goes wrong, go here. When you got lock in "HRS Electron Dipole NMR window, verify it with ocsilloscope (in the middle room) Do the same procedure for the next probe;

• To find the field set look at the "HRS Electron Dipole NMR"screen or summary screen. Remeber: Field in sec.5 "Magnet Settings" is an average of two probes, high and low.

For the Hadron Dipole:

• Go to the "HRS Hadron Dipole NMR" window;

Press Reg.Enable:YES; Press Search:ON; Type desired field into the Field Set and hit Return; Wait 20-30 minutes. When you got lock in "HRS Hadron Dipole NMR window, verify it with ocsilloscope (in the middle room)

To shut either of the dipoles down:

Go to the "Dipole Sytem" window ( electron or hadron) and push "0 Amps" button. It will take 20-30 minutes to get there.

Quads Field Setting

To power up magnets:

• Go to the "Magnet Sytems" window ( Q1,Q2,Q3 for the electron arm and Q1, Q2,Q3 for the hadron arm);
• Push Supply:ON button;
• Set polarity;

To set the desired current (in a corresponding "Magnet Systems" window):

• Type in an absolute value of desired current in Current Set;
• Wait for desired current for about 10 - 15 minutes). If something goes wrong, see sec.4.
• To find the field set look at the summary screen or corresponding gaussmeter screen.

To shut either of the quads down:

Go to the "Magnet System" window and push the Supply:OFF. It will take 10-15 minuts to get there.

Possible problems and Their Solutions

NOTE 1: You can find the complete list of all the possible problems and how to react on them either in J.LeRose writeup or in general OPS manual, both are in the counting room. Here is just a short list of most probable problems.

NOTE 2: Occasionally, if you run into communication problem (hardware fails to communicate with software, some examples described below) you may want to reboot VME crate. However, please, use it only if everything else fails.

NOTE 3: If you are in doubts about what to do, call an expert or Hall A tech support on-call.

How to Reboot:

1. • Prefered! Push one of the green buttons on the distribution box in the middle room: for electron arm - bottom raw, left column, for hadron arm - bottom raw, right column;

   OR

   • Rlogin on hallasc16(for Hadron Arm) or on hallasc14 (for Electron Arm) on account hacuser and password *******;
   • Push Cntrl-X: all windows will go blank
2. Make sure field regulation is enabled and set the dipole field as described above;
3. Set the Q2/Q3;

Q1 Problems

• Output current is equal to zero but field seems to be ok: communication failure, power supply is ok:
  1. Look at the camera screen to make sure that you really do not have any faults. If you do, see below;
  2. Push Reset button in a magnet control screen. Wait untill it complete reset procedure (red rectangular near the button will dissapear). Try it couple times if it does not work first.
  3. If everything fails, reboot.

  Recommendation for data taking: Unless you rebooted, no need to interrupt data taking. If you rebooted, stop the run beforehand.

• Output current and field are equal to zero: magnet tripped:
  1. Look at the camera screen and make sure that this fault is from DL section (slow discharge). If it is in DR section you must call a tech support.
  2. Push Reset button in a magnet control screen. Wait untill it complete reset procedure (red rectangular near the button will dissapear).
  3. Re-enter current setting, if it is required.
  4. If everything fails, call a Hall A tech support on-call.

  Recommendation for data taking: Stop data taking as soon as you saw the magnet tripped.

• If magnet starts to trip too often because lead flow is low, you might want to call cryogenics and ask them to increase a pressure.

Q2/Q3 Problems

• Output current and field are equal to zero: magnet tripped;
  1. Helium level fault: on the camera screen Interlock is red:
     1. Push Reset button in a magnet control screen. Wait untill it complete reset procedure (red rectangular near the button will dissapear). Alternativelly, you can push Reset button under SE20 mark on the magnet power supply box downstairs.
     2. Re-enter current setting, if it is required.
     3. If everything fails, call a Hall A tech support on-call.
  2. Lead flow fault: on the camera screen Quench, Interlock and Mass are red: you must take an access to the hall. In the hall:
     1. Push Reset button under QME10 mark;
     2. Push Reset button under SE20 mark;
     3. Use lever to open and close contactor;

  Recommendation for data taking: Stop data taking as soon as you saw the magnet tripped.

• Control dislplay not responding: communication failure:
  1. Push Reset button in a magnet control screen. Wait untill it complete reset procedure (red rectangular near the button will dissapear).
  2. If it fails, reboot;

  Recommendation for data taking: Stop the run before you reboot.

Dipoles Problems

• NMR is not locked and current is going in the wrong direction: software confused:

  Push Search:ON in the "HRS Dipole NMR" window. NMR should lock in a while. For detailed instructions, see here;

• On the camera display M3/M4 temerature is red: make a note in a logbook and continue to take data;
• Field and current are zeros: magnet tripped:
  1. General solution: in "Magnet Systems" window push Reset button and wait for fault to clear (red rectangular is gone);
  2. If it did not help and if, according to the "Magnet Systems"window, it is Coil Voltage or Power Supply faults - call a Hall A techical support on-call;
  3. If, on the camera display, Quench is gone red, you have to take an access to the hall. In the hall on the power supply box, pull the lever, wait for a couple minutes and then set it back;

  Recommendation for data taking: Stop data taking as soon as you saw magnet tripped.

• NMR control doesn't react and display shows all zeros: NMR Teslameter communication failure:
  1. Push Reset in the "HRS Dipole NMR" window;
  2. Re-enter all the settings, try to do it a couple of times, if it does not work first;
  3. If everything fails, reboot;

  Recommendation for data taking: Unless you rebooted, no need to interrupt data taking. If you rebooted, stop the run beforehand.

• All control displays show all zeros or all nines: computer hang up:

  Reboot, see above;

  Recommendation for data taking: Stop the run before you reboot.

Magnet Settings during E89033

Hydrogen Kinematics
Electron Arm Magnet Current(A) Field(T) Q1 - 1508.91 0.4958 Q2 - 862.47 - 0.4509 Q3 - 797.43 - 0.3970 Dipole 679.97 0.79266	Hadron Arm Magnet Current(A) Field(T) Q1 745.58 - Q2 426.73 - 0.2119 Q3 394.55 - 0.17632 Dipole 337.52 0.36795

Oxygen Kinematics
Electron Arm Magnet Current(A) Field(T) Q1 - 1496.43 0.49220 Q2 - 856.48 - 0.44700 Q3 - 791.88 - 0.39370 Dipole 675.18 0.78715	Hadron Arm Magnet Current(A) Field(T) Q1 727.63 - Q2 416.46 - 0.2068 Q3 385.05 - 0.17212 Dipole 329.56 0.35909

Helium Levels and Lead Flow Limits
Electron Arm Magnet He Level(%) Lead Flow(l/m) Q1 45 60 Q2 60 25 Q3 60 25 Dipole 40 40	Hadron Arm Magnet He Level(%) Lead Flow(l/m) Q1 45 60 Q2 60 25 Q3 60 25 Dipole 40 40

References

1. OPS Manual (in a big binder in a counting house)
2. J.LeRose, writeup on magnet operating (in a separate binder in a counting house).

Go back to the FPP Home Page

Please, send any comments on this page to Sergey Malov

Last updated July 23,1997