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Gamma-ray Large Area Space Telescope. Data Analysis 101. Bill Atwood SCIPP/UCSC Instrument Analysis Workshop II 27-Sept-2004. Modes of Working. Recon Root Files: All the information – not a tabular structure - All the tracks - All the hits on each track - Etc.
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Gamma-ray Large Area Space Telescope Data Analysis 101 Bill Atwood SCIPP/UCSC Instrument Analysis Workshop II 27-Sept-2004
Modes of Working Recon Root Files: All the information – not a tabular structure - All the tracks - All the hits on each track - Etc. Large Files – Root Macros nTuple: Key information distilled from Root Files Flat Tabular structure (Xcel Spread Sheet) Large number columns – to make possbile an "in-depth" view of data SVAC: Some of both
What Each Mode can be used for Root Files: Full analysis - Projection of tracks into subsystem of interest - In case of Gleam environment – Full power of geometry (no hard coding of numbers!) nTuple: - Many parameters of track trajectories present. Allows of simple projections into subsystem. (geometry must be entered by hand!) - Allows for correlation between variables to be studied.
My own style: - Develop Plots of interest using nTuple Often, must create new variables, make projections, etc. - Most variables of interest should not depend on location or angles: Image the variable Explore using scatter plots, profile plots, etc. - Back results up into the Root oriented Analysis Much of the Analysis Package evolved in this manner.
Analysis Package Purpose: Provide subsystem and system wide parameters for Event Analysis leit-motif: Provide a collection of templates and examples on how to use the system (TDS & Services & Tools). A set of classes where each class focuses on calculating variables associated with a subsystem - or several together All have names like McValsTool, CalValsTool, TkrValsTool,...
Image Example Require: Tkr1Gaps > 0 This is was the original idea Image the Tracker Layout
Collapse down onto one Tower Cut off the edges ( 8 mm) Collapse down onto one SSD Cut off the edges ... ( 4 mm) These are the events that shouldn't be... Lets Explore!
Require 1 Track Require Small c2 Good Events InEff. Events Require a MIP
This suggests we require: 1) Tkr1Chisq < .2 2) .8 < CalMIPRatio < 1.2 3) TkrNumTracks == 1 Leaves: 4.1 K Events ( ~ 40% Efficiency) This leaves 1 Ineff. Event
Goal: No Hard-Coded Geometry Dual use of geometry: Monte Carlo Reconstruction Method of Accessing: Geometry Service - Give global constants (size of tower, etc.) Propagator - Projects trajectories through 3D geometry - Allows for error propagation, material audits, etc.