Small beam - Post Vert A mirror

Post Vertical mirror coordinates (Branch A) for small beam sizes

March 2022, by Igor Pis

Grating	Z (d ± 0.2 mm)	Z (No. Screw revolutions)	Pitch (μm) See Note 2	Comment
"Large beam"	< 55 mm	2 to 4 CCW from "0" pos		See Note 3
SG2, SG3, SG1 standard position	51 mm	2 CCW from "0" pos	-8500	Standard position from Aug 2022
SG2, SG3, SG1	55.1 mm	"0"	(-7150) -8099 (-0.5)	The Pitch values changed in July 2022
SG2, SG3 small beam	59.2 mm	2 CW from "0" pos.	-6350
SG4 standard	61.1 mm	3 CW from "0" pos	-6050
SG1 small beam (ARPES)	69.2 mm	7 CW from "0" pos	-5200	See Note 1

Note 1: To have enough space for moving the mirror down, the top cover of the optical bench under the pneumatic valve of the mirror chamber must be removed.
Note 2: The Pitch values are approxiamte, they should be veryfied for XPS/ARPES every time the Z position is changed.
Note 3: When Z is moved up (d below 55 mm), the beam is broadening in vertical direction, the XPS signal increases, but the resolution decreases (not very much for SG2, but it can quite a lot for SG3 at high photon energies and for SG4 at all energies. The resolution(Au4f peak width) should be checked when the Z is moved here.

 

Small beam-->Large beam (SG3 and SG2)

by Federica Bondino

z= -6 turns (RIXS)

post ver A Pitch =-6400 u.u. (-2576.5 encoder, Motor: -2574 steps) -> -8200 u.u. (151.5 encoder, Motor: 155 steps) -> -8150 u.u. (to be on the axis of the R3000 analyzer)




Small beam set up for SG3 and SG2 (from SG1)

Post Vert A Z moved down (2 Turns CW, zero on the scotch scale, (distance=72.3mm) . Initial distance (-2 turns): 73mm

Post Vert A Pitch: -7200 (Encoder -1363.5) -> - 6350 u.u. (encoder -2576.5)

 

Large beam-->Small beam

▪ Post Vert Z : -6 -> 0 (distance=72.3mm)

▪ Post Vert A Pitch: -7900 -> -6100 -> 6400 (centered on R3000 axis)

 

 

REFERENCE VALUES:
SG3: POSTHOR A=-46000, POSTVERA=-6100

RANGES:

POSTHOR A: -34800 (towards T-Rex hutch, left side in the camera image) to -48200 ( towards Elettra ring, right side in the camera image).