Aperture Model

Envisage on-line aperture model providing:

• Full description of both rings - all elements including beam screens, vacuum chamber elements, transitions, detectors, TAN, TAS.
• Design aperture plus any alignment errors to be included. Plus tolerances. Track any changes to the model.
• (Access to known non-conformities.)
• Functions to derive aperture at given element or location, or element range or location range
• "Continuous model of the aperture for each of the two sequences LHCB1 and LHCB2 as a Mathematica function" (JJ)
• Incorporation of beam-based aperture measurements.
• Access to measured closed orbit, separation and crossing angle bumps...
• Inclusion of moveable elements such as collimators and roman pots.
• Include transfer lines, injection region

Applications

• Aperture scans - on-line plot of closed orbit, beam envelope, aperture and possibly beam loss monitors
• Similarly for background optimization: on-line plot of LSS aperture including closed orbit, BLMs, BCMs, tertiary collimators, separation and crossing angle bumps.
• Collimator scans: aperture, collimator positions, down stream losses
• Similarly for injection region scans.

Proposal

• Pull in extended element list from layout database including vacuum chambers, beam screens etc.
• Import aperture model from MAD in LSA database - put onus on aperture model exported to MAD from the layout database to be uptodate and complete. Version control - archive on update.
• Provide client API in JAVA to given aperture as function of element/location/ range etc.
• Provide client API to return closed orbit at any given time. Plus any known applied bumps.
• Provide client API to return collimator positions at any given time
• (Possible interface to Mathematica to give continous function if deemed necessary.)