Minutes of MAS-MA geo-meeting

 20/06 2005

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Present: Jean-Pierre Koutchouk, Walter Scandale, Marco La China, Elena Wildner, Zhengwei Gao, Gilles Berard, Natalia Emelianenko

Excused: Marta Bajko, Jerome Beauquis

Pen:  ElenaWildner

The String Model (Marco La China, string model):

Marco showed calculations on how to estimate the influence on the neighbors when magnets are interconnected. This first estimation show that the  end position of the two magnets is 0.65 mm for a maximum  interconnection distance (0.87 mm of both magnets)  This means 0.22/0.87*100%=25%.

For the dipoles the interconnection smoothes the shape. The interconnection between SSS and dipole can be a problem since the SSS is less stiff than the diploe at the BPM side. Next step: Calculate shape change of dipole, supposing feet not moving. If possible take into account feet elasticity. No change of GA, we work now in real physical space. Marco needs a sequence of dipoles and an SSS (action Elena). After this we can calculate class changes, estimate error limits. Beam screen still to be estimated (started by Zhengwei).

WP08->WP09 as a function of time (Natalia Emelianenko, stability D-points):

Natalia showed the dependence of the difference in the position of the D-points (last WP08->WP09) with time. There is a movement in x of the connection side of 0.08 (mean) and 0.2 (standard deviation). For the connection side we have 0.06 for the mean and 0.17 standard deviation.

There seems to be very small correlation between sides.

Very intriguing is the correlation between firms of the change in D-point position with time. If we calculate mean values of the movements over time windows of different sizes we can still se the correlation of the firms, x direction only, calculated over different time windows. Even if statistics is made over different years, the correlation persists and shows similar behavior. It was suggested (Jean-Pierre) to use Fourier analysis to learn more about the variation (Elena, Natalia).

We have to investigate why "last WP08->WP09B weld" is different from "last WP08->WP09 weld" (larger spread).

Change in statistical adjustment of dipole (Elena Wildner, stats adjustment):

Some refinement of the statistical adjustment has been implemented by SU, see values in the slides (slides have been presented in MEB).