Evolution of Beam-Beam-Background Simulation at CLIC

André Sailer(PH-LCD)May 12,2010

Content

• Beam-Beam Simulation with GuineaPig• Simulation and Background in the Full

Detector

Simulation with GuineaPig(GP)

• Initial distribution of Particles (bunch shape, charge density)– Largest impact on

number of pairs– Provided by Beam

Physics Group (B.Dalena, D.Schulte)

• Two data sets, different horizontal emmitance

Incoherent Pairs from GP

• Wider beam, less particles (350k 310k)

• But energy distribution per angle very similar

Detector Simulation

• Using Geant4 based Mokka

• Based on ILD concept• Different– Crossing angle– Magnetic field (4 Tesla)– Beam pipes– Calorimeters

André Sailer, LC Physics/Detector Meeting 621st July, 2009

Vertex Detector

• CLIC01_ILD • Vertex Detector

• 3 double Layers at R=31/46/60mm

• All layers 25cm long• 50 µm Active Silicon• Threshold: 3.4 keV

• 4 Tesla Magnetic Field• Hadronic Calorimeter

• 8.5λ• Absorber: Tungsten, 1cm

thick, 77 layers

Vertex Detector

Forward Region

• First Simulations done with geometry right bottom

• Different magnetic Field options– AntiDID, Solenoid, DID

only– Hits in VXD (all Layers)

(10BX)– 19000 71000 33000

Changes I

• AntiDID not an option, because it costs to much Luminosity, from now on only Solenoid field

• Using “real” CLIC QD0• Hits in the Vertex

Detector (all layers, 10BX)– 70k down to 60k

Changes II

• Larger inner radius for BeamCal– 20 to 25 mm

• Beam pipe with a single radius

• Hits in the VXD increases (all Layers, 10BX)

• From 60k to 93k

Changes III

• Using Racetrack profile• Not an option, because

of QD0 design• Reduces number of

backscatters from beam pipes

• Hits in VXD (all Layers, 10BX)

• From 93k to 41k

Changes IV

• Conical beam pipe that fits with QD0 design

• Hits reduced again• 41k to 21k

Changes V

• Moved BeamCal forward, decreased inner radius

• Space for Intra-Train-Feedback

• Hits:– 21k to 27k

• Same geometry new Beam Profiles– Hits 24k