Straw Detector Simulation with GEANT4

V. Volnykh K. Chkhaberidze 1

Straw Detector Simulation with GEANT4

Vladimir Volnykh Konstantine Chkhaberidze

V. Volnykh K. Chkhaberidze 2

• Straw Geometry (Logic, Versions, Format)

• Straw Hits (Variables, Writing Format)

• Other Outputs from Simulation

• Program Structure in the Framework of GEANT4

• Tests Results

• To Do ..

Overview

V. Volnykh K. Chkhaberidze 3

Straw Geometry

113 tube 10 cm

Full: 1808 channel in each detector

R= 0,48 cmZ= 226,96 cm

Two versions of shape:

1. Octagonal

2. Square

DoubleLayer

Detector: DoubleLayer x 4

NOTE: This is not Final version of detector and geometry could be changed many times

V. Volnykh K. Chkhaberidze 4

R = 0,48 cm Kapton

R = 0,475 cm Gas

R = 0,15 x 10(-2) cm Tunsgsten

X 452

Double layerDetector

In the case of octagonal shape of detector, tubes have different parameters depending on its position in Double Layer

X 6

X

Y U V

Vacuum

Straw Geometry (logics)

V. Volnykh K. Chkhaberidze 5

Full Spectrometer Geometry we got in Geant3 format from Oleg, then we converted it to Root TGEO format. After this operation we have possibility to use it in GEANT4 program, via the Virtual Geometry Model. So, our geometry describing language is Root TGEO.

Straw Geometry (format, view)

Square Shape

DoubleLayer Detector

Root ”gGeoManager” visualization

V. Volnykh K. Chkhaberidze 6

Straw Geometry (format, view)Octagonal Shape

Root ”gGeoManager” visualization

GEANT4 ”OpenGL” visualization

Read Out for Straws with octagonal shape is under development

V. Volnykh K. Chkhaberidze 7

Straw Geometry (view)So, at this moment, we are using Straw Detector with square

shape

The Part of full spectrometer geometry

with inserted Straws

Root ”gGeoManager” visualization

V. Volnykh K. Chkhaberidze 8

Straw Hits (variables)

X X

HIT !

Charged Track

Double layer

Detector

Det N DBL N Str N Tr - ID TrP - ID Ev - ID W. - X W. - Y W. - Z P x P y P z G Tme Point ID

Saved in Root TTree format

V. Volnykh K. Chkhaberidze 9

Other Outputs from Simulation Event

Primary K+ Pi+

Decay Vertices

Decay

Decay

Hits

file.root

•Tree 2

•Tree 3

•Tree 1

Detectors

Writing: At the End of the each Event

V. Volnykh K. Chkhaberidze 10

Program Structure in the Framework of GEANT4

DetectorConstruction na48.root VGM is used

PhysicsList

EventAction

TrackingAction

SteppingAction

RunAction

RootHitsCollection

Booking and writing TTree

Filling TTrees at the end of the each event

Finding primary K+ and Pi+ decaysStraw Hits , No SD and Hit classesClass is written by us, for writing

variables in root

EM, Hadronic processes are described

V. Volnykh K. Chkhaberidze 11

Some Results

Primary K+ Decay Vertexes: Y~X in cm

Pi+ Decay Vertexes: Y~X in cm

V. Volnykh K. Chkhaberidze 12

Detector Hits

First Straw Det.

Track Hit’s Y~X in DET 1, (first look)

V. Volnykh K. Chkhaberidze 13

To Do ...

• Read Out for Straw Detector with octagonal shape

• Digitization Program

• Reconstruction Program