H10 USER GUIDE

Lau Gatignon / SL-EA

The H10 beam is the last section of the P41 or P61 beam. It is normally used to transport either an attenuated primary proton beam of a heavy ion beam towards the NA50 experiment. Occasionally it is operated at lower beam momenta to transport e.g. electron calibration beams.

Three different optics exist for the H10. They differ mainly in the magnification factor between the primary target (T4 or T8) and the NA50 target:

  • "Parallel optics" : magnification about 0.8 in each plane. This optics is used for proton and electron beams. It was developed for the tests with a hole in the NA50 dump.
  • "Convergent optics" : magnification < 0.3 in the horizontal plane and about 0.9 in the verticcal plane. This optics is similar to the one used for the NA10 experiment.
  • "Intermediate optics" : magnification about 0.5 in each plane. This has become the 'standard' NA50 optics for heavy ion runs.

    • CONTROL SOFTWARE

    The H10 is considered part of the P41 or P61 beams. Depending on other users of the SPS, the beam to NA50 is either derived from the T4 primary target (P41 mode) or from the T6 target (P61 mode). Depending on the mode, the control program is started by typing on the beam terminal 
         RUN <227>TREE        for P41 mode
     RUN <245>TREE        for P61 mode
    Normally the beam X-terminal is configured such that the correct tree is started automatically.

    Detailed indications can be found in the P41/P42 handbook, copies of which are available in the CRN as well as in the NA50 control room.

    Note :The commands in the tree should all be upper case


    MONITORING OF THE H10 BEAM

    General performance

    The general performance is easily monitored through the command 

         STATUS / GENERAL

    This shows the intensities in 12 NA50 counters, as well as the most relevant settings related to the behaviour of the beam. Compare with previous settings in the logbooks in the CRN or at the exepriment. An example is shown below:


    Steering of the beam

    The size of the beam spot and the impact point can be measured in an analog wire chamber located slightly more than a metre upstream of the NA50 target. The profiles can be visualised by typing

         TUNE / MEAS/ MWPC / PROFILE
    and replaying DICO to show the profile in a graphics window on your X-terminal. Please see below for indications on how to correct the steering of the beam, depending on the H10 optics in use.


    STEERING COEFFICIENTS

    Note : all currents are for 450 GeV/c


    "Parallel Optics"

    	Horizontal position		BEND-12			 6.0 Amps/mm
	Vertical position		TRIM-13			12.5 Amps/mm

	Horizontal angle		TRIM-12
	Vertical angle			TRIM-11

    "Convergent Optics"

     	Horizontal position		B12 + 1.06 TR12		  45 Amps/mm
	Vertical position		TR13 + 4.75 TR11	0.84 Amps/mm

    but the lever arm in horizontal position is only ~ 3 mm.

    "Intermediate Optics"

     	Horizontal position		B12 + 3.7 TR12		 24Amps/mm
	Vertical position		TR13+2.12 TR11		10.5 Amps/mm

    but the lever arm in horizontal position is only ~ 3 mm.

    The required currents can be activated by the commands 

         TUNE / SET / BEND / number / current
    or 
         TUNE / SET / TRIM / number / current

    The trajectories of particles implied by these settings are shown below:



    The steering of the P41 and P61 beams is described in separate documents.

    Last updated : 26 July 1996 by Lau Gatignon