Event Displays and LArg

Andy Haas
Columbia U. / Nevis Labs

ATLAS LArg Week

May 11, 2005

Introduction

Displays are needed in various ways at different stages of the experiment:

Software development: understanding offline & trigger algorithms

During commissioning

Cosmics, first events, weird features of the first pb-1

“Debugging” the geometry, readout, timing, calibration, dead spots, hot spots, warm spots, noise, etc...

Data taking: online monitoring, offline monitoring, weird problems

Physics: understanding event topologies, backgrounds processes

Outreach: picture of SUSY for the front page of the New York Times

Thus displays must be flexible, and in fact multiple types of displays are desirable which are better suited for certain tasks

LArg places certain specific needs on displays

Showing its detailed geometry, in barrel, EC, FCAL

Energy deposits & clusters in various ways by eta/phi/layer, em/had, time

Correlations with other detector subsystems for electrons, photons, jets, muons, etc.

Understanding of dead material for calibration, Brem., conversions, etc.

First electron at D0 Run II

A good example of event display use during commissioning

Tracking in only one phi-sector (pi/4), in fiber-tracker only

Manual scan of 81
Z->ee candidates from first 1 pb-1

Saw a few EM clusters with high-pt, isolated, track matches, with good E/pT !

Where we stand (at ATLAS)

Atlantis

2D, multiple “data-oriented projections” : XY, eta-phi, RZ, Lego, etc.

Loosely coupled to Athena

Athena ->JiveXML (C++) -> XML files

XML files -> Atlantis (Java)

Strong support team (~5 FTE), very flexible configuration options, but harder to customize the software yourself

v-atlas

3D, like “virtual reality”

Tightly coupled to Athena

Can directly access any storegate info, change geometry, re-run algorithms, etc.

Supports a “plugin”-model. Easy to customize, but you may have to do work

The two approaches happen to complement each other perfectly!

Understanding algorithms

Atlantis does pretty well here

Can show reconstructed objects (electrons, photons, jets, MET, etc.) and associations to cells in very clever ways

elec / photon reco. & trig.

match electrons / photons to EM cells in each layer

jet reco. & trig.

clustering of cells matched to jets

lego plot, with reco objects (jets...)

jet and em object ROI - trigger

v-atlas is useful in a different way

Can display all information, especially very detailed MC truth

Everything that's in StoreGate!

Can interact with Athena and re-run algorithms more directly

Atlantis v-plot for LArg

Pt=29.3 GeV

E =31.2 GeV

LAr Presampler

LAr Layer 1

LAr Layer 2

LAr Layer 3

Island (guides eye)

Track

(enters LAr here)

Cell geometry

Area E

Cell clustering in Atlantis

Cells colored by cluster (Area  E)

Jet (Area  E)

E= 13 GeV

E= 347 GeV

Details of cell

clustering

?

Bug ?

LArg commissioning

Test beam:

Fully supported by Atlantis

Geometry also could be shown with v-atlas

Cosmic runs:

Can see muon, tile, and LArg hits in either display

Timing information could be particularly interesting: currently not supported!

First beam:

Good flexibility will be needed here

some parts of the detector may not be performing like current MC...

Displays should be well-documented and easy to use, since everyone will want to examine the first few 14 TeV events!

Simulated
cosmic

Testbeam

v-atlas : Commissioning of e/gamma

v-atlas should allow for
precise testing and
debugging of the geometry

Online monitoring displays

Trigger information should be watched closely

Larger views allowing shifters to spot anomalies -> lego plot

Can see from “across the room”

Select the right events to show in each display

A general monitoring issue

Athena-based displays (v-atlas & Atlantis) can run as modules on a monitor data stream

Atlantis has a special client/server mode, connect to the Athena server from your laptop, and browse online events

A webpage of “today's cool events” could also be set up

“Ring of Fire” at D0

A good example of why you want an event display for online monitoring

These noisy events with similar noise patterns seen in the control room at D0

Shifters would log when the problem occurred

Grounding problem? Eventually went away, and could be corrected for offline.

Event display plans

Upcoming v-atlas workshop

Goal is to write a lot of code, support more 'physics' objects

Useful for LArg

more physics quantities from reconstruction / trigger
MET / Jets / e / gamma ?

timing info?

polishing of calibration hits

We need someone from LArg !!! Volunteer, please!

Atlantis worklist

More trigger info, timing info

Lego: clusters, separate by layer

Better EC display in XY projection, layer by layer, etc.

New eta-phi drawing types, cells by color / intensity, etc.

New color scales in general, normalizing different calorimeters

Better display of jets, reco e/gamma, etc.

Summary

Basic functionality is already excellent

Two displays are under heavy development and are well supported: Atlantis & v-atlas

Working to make sure the online event displays will fulfill our needs

Web page on event displays for LArg will be available

LArg-specific information, instructions, advice, configurations

Links to and information about more general event displays, for online -> physics

Some LArg-specific functionality can and will be improved

Send me your requests, questions, comments!

Andrew.Haas@cern.ch

The evolution of the LArg part of these displays will largely be driven by your input

Andy Haas

2004-07-07T15:59:13