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 Jura side in the EHN1 hall (building 887) and downstream the final dump of the H2 beam line.

Organization

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 Simon Mataguez (mobile: 165711).

MNP22 facility Schedule for 2012

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, dso.ph@cern.ch) , 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 area and the magnet are shown. The magnet has a large aperture of 500mm (to be verified). The magnet can be operated by a dedicated terminal located in a counting room opposite the magnet: HNA-184 (887-R-B84). code 10101.

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. the maximum current is : + / - 1000 A 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 in the counting room HNA-184 (887-R-B84) opposite to the magnet area. 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 Lab View application called "MNP22" by either the desktop shortcut or via Start/All Programs/MNP22. Once the program started the initial control panel should be visible.

   

• Power converter NR21-029 should be operational. This can be verified using the control panel in the LabView application:

  • you select NR21-029

  • check on the STATUS panel that the power is on REMOTE and not on LOCAL mode

  • check on the DETAILED STATUS panel there is no fault

  • do a RESET following by an UPDATE STATUS, if you have any fault in the DETAILED STATUS section,

  The power converter is under the TE/EPC responsibility. For any problems call the First Line service (16 3668).

  Note:

  • 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:

  • by visual check in the pressure indicator situated on the side of the magnet,

  • or via the Lab View application under the  'Detailed status panel'. If the cooling is not OK you get the following message: "water-pressure".

  The cooling water distribution and in general the servicing of the magnet itself is under the TE/MSC section's responsibility. The expert to call in case of problems is Michel Ros Francisca (mobile: 16 3364).

 

• 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.

This is done using the Lab View application from the dedicated terminal in the MNP22 control room. The steps to follow to set a current in the magnet:

1. With the STB button put the power converter NR21-029 in Standby mode ( Main Circuit Breaker = ON and Switch Position = NEUTRAL)

2. SET CURRENT = 'your desired value'

3. START the converter (MCB = ON and Switch Position = NORMAL or INVERTED depending of the sign of the current)

4. for any  new current values, go to step-2 and do a SET CURRENT comment again.

Note: The DAC Value in the panel Setting Current section is an unsigned value - Example of a good state.

Ending your test - switch magnet OFF

This also done using the Lab View application. The steps to follow are:

1. With the STB button put the power converter NR21-029 in Standby mode ( MCB = ON and Switch Position = NEUTRAL)

2. With the STOP button set the MCB = OFF

Good luck and enjoy your stay at the facility !!!!