Beam Tuning

Slide Show

About FTBF

The goal of the Fermilab Test Beam Program is to provide flexible, equal, and open access to test beams for all detector tests, with relatively low bureaucratic overhead and a guarantee of safety, coordination, and oversight.

The facility consists of two versatile beamlines (MTest and MCenter) in which users can test equipment or detectors with the only high energy, hadron beam in the United States.


General Tuning

The beam line magnets are uinder the control of the AD Operations Department Main Control Room (MCR). It is best to simply phone the MCR (x3721) and politely ask them to make whatever changes to the beam are necessary. They are happy to do this.

In some cases technically involved changes will need to be made, and the MCR may elect to call in a beamline expert. Users can follow their notes in the External Beams Elog (on site only)

MTest Tuning

General - There are 4 magnets used to control the MTest beam. They are found by bringing up page S18. You will find them at the bottom of the page.

  • MT5E - Increasing current moves the beam east.
  • 2 quadrupoles MT5Q1 and MT5Q2
  • MT5V - Increasing current increases the beam height.

Dipole Calibrations

  • MT5E: 1.1mm/amp @ MT6WC1
  • MT5E: 2.1mm/amp @ MT6WC2
  • MT5V: 0.34mm/amp @ MT6WC1

MTest User Control

If you wish to do beam scans on your own, an initial one hour block of time is granted with a second one to be granted if needed. A timer on the utilities window will tell you how much time is left. One important purpose of the timeout is to insure an unattended terminal will time out rather than remain live.

  • There are four preliminary steps you must take.
    1. Call MCR and inform them that you wish to take control of the MTEST MT5 beamline magnets.
    2. They will inform you that you must first get permission of Gary Lauten (x8360). Ask for his contact information. Call him and he will ok the request and inform you of step 3.
    3. Make sure the ALCOVE CONTROL ROOM is empty and post a DO NOT ENTER sign during the scanning.
    4. Look for the ACNET terminal ID on the title bar of the utilities ACNET window. Call MCR and give it to them. They might ask for this at the beginning.
  • You are now ready to scan MT5V and MT5E.
  • The first column of numbers you see, in yellow, are the setpoints for the magnets. Change these by overtyping them. The start values will then be listed just to the left of the set points, in magenta. This allows you to easily return to your starting values. The column to the right of the setpoints are the readback values, in green. These are usually lower than the setpoint values. They can easily be off by 10A for high current magnets such as MT5E.
  • Do not exceed 720A on MT5E or +/-70A on MT5V without MCR permission! Be careful as different operators will tell you different things.
  • For MT5V, a bipolar magnet, you will probably need to change the sign of the current for part of your scan. This is done in the following manner.
    1. Move the cursor block to the dots at the extreme right edge of the screen on the line of the magnet readout and click once. This will active the control section in the center of the line.
    2. Set the current to zero.
    3. Click the "off" setting and wait 10 seconds.
    4. Click the "plus" or "minus" setting (whichever you need) and wait about 1 minute.
    5. Click the "on" setting and wait 10 seconds.
    6. Type in the desired current.
  • There are several scalers on page S17 that may be of use. They are reset at the beginning of each spill.
    1. MT6SC1 - This counter is in MT6A at the upstream end. It counts singles and so is not the best counter to use for normalization.
    2. MT6SC2 - This counter is just in front of the MT6.1 beam stop and is in coincidence with MT6SC1, which fully shadows it. This counter is large enough that you will find it difficult to move the beam off of it.
    3. MT6SC3 - This counter is just downstream of the MT6.1 beamstop at the upstream end of MT6.2. It is in coincidence with MT6SC1.
    4. MT6SC4 - This counter is just upstream of the MT6.2 beamstop at the far downstream end of MT6.2. It is in coincidence with MT6SC1.
    5. The 4 finger counters are also available as well as 4 empty slots you may use for whatever is needed. Feel free to put the finger counters in coincidence with other counters if needed.
  • Be sure to take down the sign on the ALCOVE CONTROL ROOM when you are done!