preparation of wall position alignment of a and c side in closed position creation of reference...
TRANSCRIPT
M1 Alignment T.Schneider 1
•Preparation of wall position
•Alignment of A and C side in closed position
•Creation of reference system
•Translation of reference system to open position
•Balcony alignment
•Alignment system for X, Y and horizontal level
•Interlink of Front and Back alignment
•Sequence for Alignment procedures
•Conclusion for the M1 alignment system22 February 2009
M1 Alignment
M1 Alignment T.Schneider 2
End of last year we had a first look on the absolute position of the M1 A and C side
Looking on the beam pipe position we had to lift both sides up by about 4cm
With the help of the survey team we measured the beam supporting the walls
22 February 2009
Preparation of wall position
M1 Alignment T.Schneider 322 February 2009
Preparation of wall position
-10.00
-8.00
-6.00
-4.00
-2.00
0.00
2.00
4.00
6.00
8.00
10.00
3.815
3.820
3.825
3.830
3.835
3.840
3.845
3.850
3.855
LHCb M1 rail profile - Walls opened, chambers not installed05 Dec 2008 and 17 Dec 2008
Ysu (m)
Zs
u (
m)
M1 Alignment T.Schneider 4
•The walls were put in a kind of “close to closed” position (25cm)
•With the help of a plump we aligned the inner edges of both sides vertically
22 February 2009
Alignment of A and C side in closed position
M1 Alignment T.Schneider 5
•The system has been closed totally
•The beam pipe cut out was well adjusted in X and Y around the beam pipe
•This position is the starting point for our alignment. About the shape of the walls we do not care so much.
•We need a kind of reference system visible in open and closed position
22 February 2009
Alignment of A and C side in closed position
• M1 closing
M1 Alignment T.Schneider 822 February 2009
Translation of reference system to open position
-10.00
-8.00
-6.00
-4.00
-2.00
0.00
2.00
4.00
6.00
8.00
10.00
3.815
3.820
3.825
3.830
3.835
3.840
3.845
3.850
3.855
LHCb M1 rail profile - Walls opened, chambers not installed05 Dec 2008 and 17 Dec 2008
Ysu (m)
Zs
u (
m)
M1 Alignment T.Schneider 922 February 2009
Translation of reference system to open position
-10.00
-8.00
-6.00
-4.00
-2.00
0.00
2.00
4.00
6.00
8.00
10.00
3.815
3.820
3.825
3.830
3.835
3.840
3.845
3.850
3.855
LHCb M1 rail profile - Walls opened, chambers not installed05 Dec 2008 and 17 Dec 2008
Ysu (m)
Zs
u (
m)
M1 Alignment T.Schneider 1022 February 2009
Translation of reference system to open position
-10.00
-8.00
-6.00
-4.00
-2.00
0.00
2.00
4.00
6.00
8.00
10.00
3.815
3.820
3.825
3.830
3.835
3.840
3.845
3.850
3.855
LHCb M1 rail profile - Walls opened, chambers not installed05 Dec 2008 and 17 Dec 2008
Ysu (m)
Zs
u (
m)
M1 Alignment T.Schneider 11
After the opening of the system (working position) the reference system has been brought again into vertical position. This we have been done by adjusting the outer fixation screw of the walls.
The resulting difference in Y has to be taken into account (A=-3.25mm,C=-4mm)
For the translation in height (Y) of Survey coordinate system to the physics one a correction of 43.6mm (depending on Z of M1) is given
22 February 2009
Transfer of reference system to open position
M1 Alignment T.Schneider 12
•Using this reference system we were able to measure the end of chamber fixation rail positions
•All front side top and back side bottom positions were measured . Some additional ones (back top) were used for crosschecking.
•These coordinates once translated to absolute values for the closed position were the starting point for Wander to do the balcony alignment for the close chambers
22 February 2009
Balcony alignment
M1 Alignment T.Schneider 14
•Alignment bars with precise holes at the nominal chamber centers positions (X) have been machined
•4 different types are need
•These bars will be fixed and well aligned on the top and bottom of the walls
•Precision rods will be inserted into these holes
•Thin wires fixed between these rods will built a kind of grid system for the X–position of the chamber centers
•Additional square bars on top of these rods will guarantee good reflection for the Y laser distance measurement
•With help of additional traces on the chambers we will be able to align the horizontal level of each chamber
22 February 2009
Alignment for X Y and horizontal level
M1 Alignment T.Schneider 1522 February 2009
Alignment for X Y and horizontal level
Alignment steps:
Horizontal level alignment with precision water level
Y-alignment measurement with laser meter to top and bottom square block
X-alignment with help of wire grid
M1 Alignment T.Schneider 1622 February 2009
Alignment for X Y and horizontal level
Calibration of new laser meter
The new laser meter mode has a 0.1 mm digit compared to 1mm from the old one.
It has been compared to an interferometer of the SU group.
We should include a linear correction for the Y-measurement. 0 5 10 15 20 25
0.0000
0.0002
0.0004
0.0006
0.0008
0.0010
0.0012
f(x) = − 2.0122061215504E-05 x + 0.000640633994060022
LHCb M1 - CALIBRATION DISTO D3 S/N 180430516 A LA BASE GEODESIQUE07 Janvier 2009
INTERFEROMETRE - DISTO D3
Interfero - Disto
Linear (Interfero - Disto)
Distance (m)
Inte
rfer
o -
Dist
o (m
)
M1 Alignment T.Schneider 17
•Important point is to interlink together Front and Back alignment in the best way possible
•The bottom front area is unfortunately not accessible for any survey measurement
•For the top bars we will link directly front and back together . This is done via additional rods passing the wall
•For the bottom of the wall this is unfortunately not possible due to the cable routing already done. For the bottom front ones we will also pass the wall with precision rods give access for the survey measurement
22 February 2009
Interlink of Front and Back alignment Side view top
Side view bottom
Back Front
M1 Alignment T.Schneider 1822 February 2009
Sequence for Alignment procedure
Rich detector
M1 Alignment T.Schneider 1922 February 2009
Sequence for Alignment procedure
M1 Back side 1st step:
M1 in open position
Alignment of B/C/D column
M1 Alignment T.Schneider 2022 February 2009
Sequence for Alignment procedure
M1 back side 2nd step :
Calorimeter in open position and M1 more or less closed
Alignment of A-column
The access to the chamber crosses is good
The walls have to be re-aligned for the horizontal level
M1 Alignment T.Schneider 2122 February 2009
Conclusion for the M1 Alignment systemImprovements for the M1 alignment:•Permanent reference system on the wall easy visible for survey•Good interlink in-between reference system and alignment system•Precision (+-0.1mm) alignment bars on top and bottom of the wall•Front and back alignment will be well interlinked•The new laser meter has one digit better resolution (1mm=>0.1mm). Measurement to top and bottom•The reflection surface for the Y-measurement has been improved•We have no more free hanging plumbs but a more precise and stable wire grid for the X alignment•Chamber cross quality has improved•Alignment with nacelle to reach each chamber
- Inner part Front very bad access (not possible to climb down)- Faraday cages in the way for Y and X alignment- First align close layer and then in a 2nd step the far one