Introduction - Organization

For the needs of the CERN users to test LHC equipment under magnetic field a facility with a large dipole magnet was created in the North Area Experimental Hall (EHN1). The large dipole magnet, called MNP22, is located at the Salève side in the EHN1 hall (building 887) at next to the begining of the H8 beam line.


    To coordinate the activities, requests for the use of the facility, the installation, and technical support for the facility is under responsibility of EN-MEF-LE section. For questions about the magnet (control) you can contact Bastien Rae (mobile: 167388).

Points to remember:

  1. During their tests, the users are responsible for their security in the dedicated area. The different apparatus used must follow the electrical safety instructions (e.g.: high voltage, grounded correctly, etc...). Depending on the size and nature of the tests a safety inspection may be needed before. In case of doubts please contact Christopher Griggs (tel: 73314, mobile: 163948, , the DSO of the PH Dept. or the TSO of the EHN1 building Mickael Jeckel.

  2. It's very important that you maintain the area clean in particular at the end of your tests. Material that will be left there, in particularly unidentified, risk to be thrown away without notice.

  3. It is not guaranteed that the magnet will be operational during the accelerator shutdown (typically November to March each year). This because the magnet needs the cooling water to operate and consumes quite some current so it may be switched off during critical days. It is a good practice in case of doubts to contact the technical responsible for the facility.

Area Layout

In the photos below the magnet are shown. The magnet has a large aperture of 500mm (to be verified). The magnet can be operated by a dedicated terminal CWO-HNA184-MNP located next to the MNP22 zone.


The magnetic field

The magnetic field map has been measured in 2003 by the ALICE TOF group and is shown in the figure below.


The magnet is powered by the power converter NR21-029.

  1. the maximum current is : + / - 1000 A
  2. Presently only DC mode is possible




Operational Issues

Information concerning the magnet operation can be found below:


Setting up to start the magnet:

Before starting, the availability and well functioning of the following systems should be verified:

  • Control system used via the windows PC: CWO-HNA184-MNP located next to the MNP22 zone.

     What needs to be done:

    1. Login into the computer using your NICE account. In case you experience network problems you should contact the CERN network support service and ask for help or advice 77777.

    2. Launch the CESAR application called "MNP" by either the desktop shortcut or via Start.

    3. Open the magnet window and click on "Set Current".


  •  For any problems call the CCC (77500).


    • Because there is no automatic update, you have to do an UPDATE STATUS after each action.

    • It takes one cycle length (of the SPS machine which is about 20sec) before each command to the magnet is executed. This is a feature of the system which is hard to change.

  • Cooling water of the magnet should be operational. This can be done:


  • Finally, the "Red Button" installed ON the magnet itself should be in the un-locked position. In case it is pushed, it inhibits the power converter and no current can be set. An error in the Lab View screen is shown. If pushed, to release it it must be turned clockwise (to be verified).

  • Important info:

As mentioned above, operation of the magnet during the shutdown is not guaranteed. There are also cases (like critical days) where either the power supply or the cooling water circuits are scheduled to be unavailable. Therefore, before contacting various experts and making them loose their time Simon Mataguez should be contacted to verify that indeed the magnet CAN be operational.


Big success and enjoy your stay at the facility!!!!

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