Implementation of BeamCal in Mokka

Alexandra Popescu, Aura Rosca

West University of Timisoara

FCAL Collaboration Meeting

6-7 May, Krakow, Poland

7.05.2008 2

Overview

• BeamCal: functionality and structure

• Detector construction

• Sensitive detectors

• Summary

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BeamCalCompact EM calorimeter with a sandwich structure:

• 30 layers of 1X0: 3.5 mm absorber and 0.3 mm sensor

• Angular coverage: ~5-45 mrad

• Situated at 3450 mm from the IP

Purposes:

• Provide electron and photon identification down to polar angles of a few mrad

• Protect the inner part of the detector by reducing backscattering from inner parts

• Assisting beam diagnostics

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Mokka implementation

• Create a local copy of the central database

• Construct the geometry of the detector

• Define the sensitive detectors

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Geometry construction

• Drivers: C++ code

• Databases: MySQL database

• Sub-detectors: a combination of drivers and databases

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Drivers• A class which inherits from VSubDetectorDrivers class

class BeamCal00: public VSubDetectorDriver

• The actual construction of the geometry is made by the ContextualConstruct invoked by the geometry manager

G4bool ContextualConstruct(const CGAGeometryEnvironment &env, G4LogicalVolume *worldLog);

• To be available the driver has to be created using the INSTANTIATE macro available in “CGADefs.h”

#include "CGADefs.h"INSTANTIATE(BeamCal00)

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Geometry data model“models03” database is composed of several tables:

• detector_concept• ingredients• model• model_parameters• parameters• scripts• setup• setup_parameters• sharing• sub_detector• tmp_databases

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Geometry data model

model

name

description

detector_concept

model_status

sub_detector

id

name

db

driver

description

ingredients

id

model

sub_detector

build_order

sharing

driver

parameter

driver_default_value

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DatabaseCreate a database, using a MySQL script, with the relevant geometry parameters for the detector

CREATE DATABASE `beamcalX01_14`;USE beamcalX01_14;DROP TABLE IF EXISTS `beamcal`;CREATE TABLE `beamcal`(`Rinner` double default NULL,`Router` double default NULL,`sPhi` double default NULL,`dPhi` double default NULL,`nWafers` double default NULL,`BPmaxR` double default NULL);INSERT INTO `beamcal` (Rinner, Router, sPhi, dPhi, nWafers,

BPmaxR) VALUES (20., 150., 200., 320., 8., 67.);

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Connect the driver and the database to form a sub-detector:

Geometry constructionsub_detector

id

name

db

driver

description

• name: BeamCal

• driver: BeamCal00

• database: beamcalX01

Create a detector model that uses this sub-detector:

ingredients

id

model

sub_detector

build_order

• model: LDC01_05Sc

• sub_detector: BeamCal

Make the relevant geometry parameters known to the driver:

sharing

driver

parameter

driver_default_value

• driver: BeamCal00

• parameter: ILC_Main_Crossing_Angle (default value is 14 mrad)

model

name

description

detector_concept

model_status

7.05.2008 11Graphite (100 mm)Air gap Diamond

Kapton GoldTungsten

Pair monitor

BeamCal Geometry

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Backward region

BeamCal GeometrySegmentation:

• 17 ring (r)

• 8 sectors (phi)

• 140 cells/sector

~ 8mm

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Sensitive detector

• Hit class(es)- CalHit (the generic hit class for calorimeters)

- TRKHit (implements a simple hit for the tracking devices)

• Hit collection

• Sensitive detector class- has to inherit from the abstract class VSensitiveDetector

• Register the sensitive detector object using the RegsiterSensitiveDetector() method

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Hits

Forward region Backward region

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Simulation studies

RM=11.8 ±0.4 mm

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Summary

• Implemented in Mokka a realistic description of BeamCal’s geometry

• Moliere Radius = 11.8 mm (preliminary result)

• LC TOOLS note in progress