2. SLAWG #15 ZS fiducialisation and alignment today
B. Balhan
08/03/2017

3. Outline ZS individual tank alignment in laboratory SPS alignment LSS2
Girder Alignment
ZS wire Alignment accuracy
Final alignment using beam
How to improve
08/03/2017
Slawg#15

4. ZS individual alignment in laboratory
In order to avoid alignment process in the SPS, all ZS are aligned in the lab using a “ ZS alignment jig” to copy all references
Alignment sequence:
Install ZS model on alignment banc
with correct levelling (tilts)
Setup optical measurement system
In vertical and radial position
(ZS wires, Alignment Target)
Replace ZS model by ZS to align
Mechanically adjust tilts, upstream and downstream wires and alignment targets.
Set cathode positioning
Set 0 anode positions
Using this method, all ZS are identically aligned and “Plug and Play”
ZS are placed on 3 spherical Feet, keeping the positioning.
08/03/2017
Slawg#15

5. SPS alignment LSS2
Since all ZS are identical, once the girder feet are correctly aligned, ZS can be removed and replaced without need for an alignment campaign in the ring.
Tunnel alignment sequence:
The girder is placed in nominal position
Quadrupoles ( ) targets are used as references.
Tilts are checked and adjusted if required (radial & longitudinal).
Vertical and Radial positions are checked and adjusted if required.
08/03/2017
Slawg#15

6. Girder Alignment.
During re-cabling campaign (irradiated cables replacement, last one in 2009),the girder levelling is fully checked, ZS and pumping modules feet are as well adjusted using “ZS alignment jig” or non radioactive tanks.
Upstream & Downstream Girder adjustment
08/03/2017
Slawg#15

7. ZS wire alignment accuracy
In order to reduce the tilt effect on the wire position,
The Anode shaft can be used to know exact upstream & downstream wire positioning (initial laboratory measurement required).
Initially designed to improve alignment, but not used since at least 30 years.
08/03/2017
Slawg#15

8. ZS wire alignment using beam
The Final alignment is done using the beam, few times a year…
08/03/2017
Slawg#15

9. How to improve
During scans, the limitation factor is the accuracy of 0.1 mm of the anode motorisations displacements
(bigger than the wires width 60µm & 100µm)
The actual Anode motorisation seems to be more accurate
(at least 0.05 mm)
An estimation has been done by Ch.Boucly to improve acquisition and control of these displacements ~ 100 kCHF,
New cabling required
New control (Software/Hardware), DAC/ADC 16 bit
Use motorisation in servo instead positioning ?
Test to be scheduled in 867 to validate the estimated accuracy.
08/03/2017
Slawg#15