LG 11/18/2004

First Look at MIMOSA Glued to Cable / Carrier Flatness from High Granularity “Cross” Measurement

We are beginning to measure the characteristics of the mechanical ladder prototypes with respect to flatness and stiffness. We are using this opportunity to develop the construction techniques that we hope to use in making the real detector, using the feedback gained from carefully measuring and testing what we have constructed.

The mechanical prototype constructed has the following construction;

End View

Top View

In addition to the usual surface measurements we did a high granularity “cross” of 0.5 mm measurements on the 2^nd MIMOSA from the end.

The data with linear fits is shown below;

To begin with, the MIMOSA is relatively flat in X but has a “dish” shape in Y. The magnitude of these distortions is, however, quite small. As we can see, in X the linear fit appears to be a good approximation and should give a quite easy parameterization. The linear fit in Y is poor but a polynomial fit should work well. This will allow us to make some minimum number of measurements of the detector positions on the ladders and locate the individual pixel position to the required accuracy by a parameterized location function.

Clearly we need to extend these measurements to other MIMOSA assemblies and get a good look at the scale of the imperfections as well as the shape and magnitude of the distortions that we can expect. We will follow this up soon with surface flatness, bending calculations and measurements, and more data on possible parameterizations. This is just a first look.