20130225 Quad Scan Analysis

Previous quad scans took a lot of time and don't provide the clearest picture. During the previous quad scan on shift on the 20130222, the following procedure was used:

• Typically 25 minutes per magnet current with 5 minutes changing, minimising background again (post ip) and ensuring don't loose signal
• 3A steps, 9 points measured

Despite increasing the chamber speed to 50um/s, the horizontal scan still takes the most time and with a typical uncertainty of +-10um on the horizontal size (fitting to be improved..) it's still not the most accurate.

• The time for this whole process needs to be reduced
• The horizontal uncertainty ideally needs to be less
• Ideally, 2 or 3 vertical scans would be repeated at each current for statistics.

Solutions

• OTR images provide horizontal sizes with a lower uncertainty than the laser-wire scans and can be done much quicker at the end.
• Use the OTR images for horizontal information and do only a small horizontal scan for centring.
• Perform 2 non-linear scans at each location
• Optimise non-linear scan points to reduced number of points required for the same uncertainty or even lower uncertainty