Bill Atwood, SCIPP/UCSC, September, 2004 GLASTGLAST1

Data Analysis 101Gamma-ray Large Area Gamma-ray Large Area Space TelescopeSpace Telescope

Bill AtwoodSCIPP/UCSC

Instrument Analysis Workshop II27-Sept-2004

Bill Atwood, SCIPP/UCSC, September, 2004 GLASTGLAST2

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 FilesFlat Tabular structure (Xcel Spread Sheet)Large number columns – to make possbile

an "in-depth" view of data

SVAC: Some of both

Bill Atwood, SCIPP/UCSC, September, 2004 GLASTGLAST3

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.

Bill Atwood, SCIPP/UCSC, September, 2004 GLASTGLAST4

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.

Bill Atwood, SCIPP/UCSC, September, 2004 GLASTGLAST5

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,...

Bill Atwood, SCIPP/UCSC, September, 2004 GLASTGLAST6

Require: Tkr1Gaps > 0 This is was the original idea Image the Tracker Layout

Image Example

Bill Atwood, SCIPP/UCSC, September, 2004 GLASTGLAST7

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 thatshouldn't be... Lets Explore!

Bill Atwood, SCIPP/UCSC, September, 2004 GLASTGLAST8

Require 1 Track

Require

Small

Require a MIP

InE

ff. E

ven

ts

Goo

d E

ven

ts

Bill Atwood, SCIPP/UCSC, September, 2004 GLASTGLAST9

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

Bill Atwood, SCIPP/UCSC, September, 2004 GLASTGLAST10

Goal: No Hard-Coded Geometry

Dual use of geometry:Monte CarloReconstruction

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.