beamline Documentation 8.2.1, 8.2.2 and 8.3.1  
(c:\My Documents\Beamline Documentation 8.doc) <== This is on the "other" front
end machine.


1.1 Setting up the Monochromator Heidehain Display
1.Cycle the power.  Display shows <Ent...CL>
2.Press the <ENT> button. Display shows reference angle that you have to drive through. 
3.Check angle on end of Monochromator Body.
4.Using Theta motor drive through that angle.
5.Display starts changing when reference mark is detected.
6.The readout display is now working.

1.2 Transferring the Heidenhain display encoder reading to the beamline software
1.The beamline software can read and reset/recalibrate itself by reading the HH diplay
2.Click on         Motors / Set Theta to HH value

Occasionally the Theta encoder register just looses its counts and reads zero. At that point the mono energy scale is badly screwed up and one knows about it as the mono drives to the wrong energy – beam may well go. The Theta value on the beamline front panel reads different from the HH encoder display. This is an intermittent problem – will get fixed when it gets worse, or it may go away. 
To fix do item 2 above. 

1.3 Calibrating the Monochromator with Copper Foil

Scan eV versus I zero signal. The output should look something like fig.1

The max of the derivative should be at 8979eV. If it is not then drive the mono to the supposed energy the Monochromator thinks is the max of the derivative. When there set that value to 8979eV (‘set button’ on Motor Panel / Mono eV)

For reference the Monochromators are set up such that when they are at 8979eV
Beamline 821 will read 12.1280 degrees on the Heidenhain
Beamline 822 will read               degrees on the Heidenhain
Beamline 831 will read 10.8357 degrees on the Heidenhain < (THIS EDITED BY G.M.)





     ***********In Original Graph's are  here *******************






Figure 1. Copper absorption edge

2.1  How to set up the Apertures

1.Check all motors are homed
2.Open all apertures
3.Scan Ap7 versus Izero beam to determine when it clips the beam edge
4.Repeat for Ap9.
5.Move Ap7 and Ap9 to these beam edge positions
6.Increment Aperture size equal amounts until Izero = zero
7.Record Ap9 and Ap7 positions – these are the positions when the paddles are half way in the beam
8.Input these recorded values into Beamline Parameter table under the fields requiring input values for when the paddles are half way in. Press SAVE.
9.Set Horiz aperure size  = 0
10.Set Horiz aperture position  = 0
11.Repeat for Vertical apertures.

3.1 Beam line set up from nominally (mis) aligned beamline.

1.Adjust M1 tilt so that beam goes through Mono aperture correctly. This can be done by scanning M1 tilt versus I-mono-in, but it needs cross checking by visually viewing the Mono aperture.
2.Get mono light out onto the Phosphor paddle – maximize throughput flux by adjusting Theta2.  (Tune rocking curve button)
3.Hopefully beam is through to YAG crystal at sample position and viewable with Long working distance K2 microscope. (shutter is open) If it is not then you have to monitor the beam position monitors and try to get them equal by means of M2 tilt and Chi2. When roughly equal  you should see the beam on the YAG.
4.Set up Chi2 by scanning between 7000-14000 ev (1000ev steps) and plotting out Horiz centroid of beam. Adjust Chi2 (in 0.0005 degree increments) to get the plot as flat as possible.
5.Adjust M2 Yaw (manual) to get best spot shape. This best done with 3 mrad Horiz sample convergence and defocusing M2 by moving M2 tilt up – the beam is then an unhappy smile – adjust M2 yaw for symmetry.
6.Scan M2 tilt versus Horiz FWHM for best M2 tilt. (minimizing spot width)
7.Scan M2 bend up vs M2 bend down vs Vert FWHM for best M2 bend up/down