sPHENIX is a new detector at RHIC.

[Anthony Frawley <afrawley AT fsu.edu>]

Dear tracking subsystem (and other) collaborators,

I am following up on the discussion at today's software meeting about tracking detector alignment, organized by Chris.

We agreed that it is now time to implement in our code the framework that will be used to de-align and re-align the sPHENIX tracking detectors.

A) After considerable discussion, I think we agreed that we want to:

--- De-align the detector at the detector simulations level, before we generate g4 hits.

--- Develop techniques to align the detector elements starting with reconstructed hits - i.e data.

B) I think we agreed that:

Experts from the three subsystems should implement the scheme to de-align their detector.

--- Decide which elements will be moved from their ideal position, and in what coordinates.

--- implement the alignment map, and use it in construction of the detector model in simulations.

Tracking experts will develop code that can be used to align the detectors.

--- Using cosmics.

--- Using collision data.

First, it is important to hear from anyone who thinks we should do this differently than I have outlined above. We will be living with what we decide to do for the next 10 years, so let's argue about it now rather than later 🙂.

It would be good to hear from detector subsystem experts at the next software meeting (Tuesday at 1 pm EDT) about the alignment of their detector - elements that can move around, degrees of freedom, etc. I will contact each group.

Thanks

Tony