May 29 - Jun 4， 2005

BESIII Annual Meeting，Beijing 1

The BESIII DetectorDescription With XML

Jun 1, 2005

Zhengyun You ， Yajun Mao

(School of Physics, Peking University)

May 29 - Jun 4， 2005

BESIII Annual Meeting，Beijing 2

Outline

The Motivation

What’s XML?

BESIII Detector with XML

Schema for Event Display & Reconstruction

Summary

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Overview of BESIII Offline Software

GEANT4 GAUDI ROOT

BOOST BOSS(BASF)

Detector related informationgeometry, material, calibration…

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May 29 - Jun 4， 2005

BESIII Annual Meeting，Beijing 4

A New Solution With XML

EventGenerator

DetectorSimulation

DetectorResponse

Decode +Reconstruction

PhysicsAnalysis

EventDisplay

DAQ

GENBES, PYTHIA BOOST(GEANT4)

BESIII Offline Flow Chat (Schematic)

GEANT4Schema

ROOTSchema

ROOTSchema

XML descriptionKeep sub-structureGDML=> GEANT4

Digitalization: simpleidentical geometry forSimulation, Reconstruction, Event Display

Share schema

BESIIIRaw Data

DatabaseGeom.+Cal.

SimulatedData

DST orDST

May 29 - Jun 4， 2005

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XML (eXtensible Markup Language) is an industry standard tool.

XML has great power in auto-distribution and data exchange over platforms.

XML document

Same content Different formatstandard

auto

What’s XML?

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A Simple Example With XML<?xml version="1.0" encoding="UTF-8"?>

<gdml xsi=“/scratch/youzy/gdml/gdm_1.1.xsd”>

<material name=“air” … … > <material name=“Iron” Formula=“Fe” Z=“26.0” D=“7.84“ … >

<solid box=“world” x=“1*m”, y=“1*m z=“1*m” ><solid box=“layer” x=“0.5*m”, y=“0.8*m” z=“0.1*m” >

<volume name=“logLayer” solid=“layer” material=“iron”

<child name=“layer2” volumeref=“logLayer” pos=“…” rot=“…“ /child>

<child name=“layer3” volumeref=“logLayer” pos=“…” rot=“…“ /child>

<volume name=“logWorld” solid=“world” material=“air”>

</volume><setup name =“det” world ref=“logWorld” /setup></gdml>

airiron

<child name=“layer1” volumeref=“logLayer” pos=“…” rot=“…” /child>

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BESIII Detector Overview

MDC TOF

EMCMUC

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BESIII MDC with XML

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BESIII TOF with XML

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BESIII EMC with XML

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BESIII MUC with XML

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Schema for Reco. & Event Display Geometry, Materials,

Calibration…

Classes for Simulation

XML description

Classesfor Reconstruction

Classesfor Event Display

GEANT4 Schema

RO

OT S

chem

a

ROOT Schema

XM

L w

rite

r

Improved GEANT4 Schema: add three new shapes: Hype, TwistedTubs, IrregBox

Wrote ROOT-based Schema for reconstruction & event display

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Event Display Package

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An Example of An Event

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Geometry Classes for Reco.

BESIII

Mdc Tof Emc Muc

Layer

Wire

Bucket

Scintillator

Phi

Theta

Crystal

Segment

Layer

Iron

Rpc

Strip

Bakelite

Gas ChamberInterested Objects

Applied in MUC Got Identical results

Access geom. : simple Reconstruction: simple

Will be applied in other sub-system soon

May 29 - Jun 4， 2005

BESIII Annual Meeting，Beijing 16

Summary

Applied XML to handle BESIII detector in offline software

Improved GEANT4 schema & wrote ROOT-based schema

Identical geometry for all offline packages becomes practical

Could handle very complicated structure in a rather simple way

The new technique makes the offline code simple & robust

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THANK YOU！