1) News on the long scale length calibration 2) Results of the two surveys performed on plane 7 Set 1: morning of 12/11/2004 Set 2: morning of 19/11/2004 Some improvements on the way plane 7 is suspended and aligned were implemented in between the two measurements and should have visible effects in Set2

Long scale calibration sources: installation of Target holders on the XPC supports, 4 point will appear systematically in all the measurements. These 4 points have to be measured once forever with the laser tracker in order to provide 6 long distances for the calibration of all the measurements (replacing the 4 holes made on the mounting arch) We should also measure with the laser tracker the 4 holes on the mounting arch in order to perform a reanalysis of the pictures taken on plane 8

The long distance calibrations are not available yet, so the results should be considered preliminary since are based only on the extrapolation of the local scales, the analysis will be redone with the long range scales: mm No significative syst. effects (up/down, left/rigth) visible on the external control frame Some latest news from Friday afternoon discussion with Mario about the position of the bolts on the magnet that we want to use in order to provide the long range calibration for the photogrammetry. … See next page TT

The bolts were positioned with the laser-tracker already with 0.1 mm precision and these positions are known. In principle they should not have changed during the assembly of the magnet and also the M16 hole and the support for the photogrammetric targets should not have introduced a significative bias (they should be both more precise than 0.1 mm). So while waiting for the occasion to remeasure directly these positions with the laser-tracker we can already use this information from Mario. These 6 distance informations will be introduced in the analysis in order to calibrate exactely the scales. Meanwhile, it is quite interesting to compare Mario's distances with the ones measured with the photogrammetry by extrapolating the short scale bars.This use of the short scale gauges is something that we do temporary in the analysis just to have a fast result but the final result in XZ will have to rely on the long distance calibration. Targets Mario Photogrammetry with local gauges Horizontal top Horizontal bottom Vertical left Vertical rigth It is good to see that the photogrammetry with the last improvements, even with a scale defined as the extrapolation of the short scale bars, is already able to find over long distances the correct values at the level of about 1 mm.

Definition of an absolute « magnet » coordinate system for the measurements Set 1 and Set )We take the points measured in both Set1 and Set2 with the photogrammetry at the same time as all the other targets on the TT 2)These 4 points are sligthly off the surface of the magnet, with an equal offset for the 4 3)We define a plane with the 3 points 200,201,203 4)We define the origin of the new coordinate system in 200 5)We take as Z axis ( ) and as X axis ( ) 6)These two axes are orthogonal, a very small deviation from 90 degrees is corrected by rotating ( ) staying on the plane 200,201,203 7)The Y axis perpendicular to the magnet is defined by the vector product of the Z and X X Z Y After computing the 3 versors we have an orthonormal system centered on 200 with the XZ plane passing for the points 200,201,203 (parallel to the surface of the magnet), and with the Z axis defined by ( ) and the X axis ( )

Notes on the plots shown in the next pages: All the positions are now absolute, with respect to the magnet coordinate system, so other then the local deformations of the plane one can check also the distance of all the measured points with respect to the magnet and verticality or horizontality Units are mm, be careful since the scale of the histograms is self normalizing on the range of the points The position in XZ of the magnetic targets is not the same in the two measurements, they had to be moved on the end-caps during the cabling, the pin targets by construction cannot move Each type of Target (magnetic, adhesive, pins) has its own offset perpendicularly to the TT plane due to the tickness of the Target holder. These ticknesses are not yet subracted from the measured values. So comparisons for the coordinate along the beam (Y) are always for the same kind of targets The long scale calibration with the 4 reference point on the magnet is not included yet, it is anyway an effect of the order of 1.5/10000 which will be negligible for the considerations shown in the next pages which concern the coordinate along the Y axis

Planarity, measured with the coordinate perpendicular to the magnet plane (Y), at the level of the end-caps with the pin targets (2 points/end-cap) as a function of the horizontal coordinate (X) Y is the « beam axis » coordinate X is the horizontal Z is the vertical Set 1 Comment: in Set2 it was attempted to improve the alignment of the bottom part of the TT with respect to the magnet. This worked apart for the first vertical module which is skew by about 8 mm The shape of the positions of the top end-caps comes from the deformation on the yellow I-beam which supports the TT, it is the same in both measurements Bottom end-caps Top end-caps X X X X X X Z Y Y Y Y Set 2

Same measurement as the previous transparency but performed using the magnetic targets on the end caps and on the yellow plate Set 1 Set 2 Bottom end-caps Top end-caps Yellow plate Comment: The picture is the same as for the one of the previous transparency obtained with the pin targets. The kink on the yellow plate is very well visible. From time to time two targets were put about at the same x but at the top and bottom of the yellow plate. At the rigth of the plate these two targets have very different Y, there the plate is quite skew with respect to the vertical, better in Set2

Set 1 Set 2 Comment: in Set1 the rock side of the TT was not vertical by about 45 mm from the bottom to the top (the bottom was closer to Borexino). This is improved in Set2, where the two sides behave in similar way. Both in set 1 and set 2 there is a concavity about in the middle of the detector Coordinate along the beam axis (y) as a function of the vertical coordinate (z) for the pin targets on the end-caps of teh horizontal modules bottom top Left end-caps right end-caps

Same measurement as the previous transparency but performed with the magnetic targets on the end-caps instead of the pin targets Comment: the behavior is quite similar to the one measured with the pin targets on the end-caps. Note that often we had two magnetic targets at the same heigth on the two sides of the horizontal modules endcaps, the fact that they do not fall at the same y shows that the end-cap is tilted on the horizontal plane, it is not perpendicular to the beam axis (i.e. not parallel to the brick wall) bottom top Set 1 Set 2 right end-caps Left end-caps