Background in the CILD01fw

Weekly Detector Meeting

May 5, 2009

André Sailer

CLIC_01_ILD

Content

• Further changes to the ILD Detector– Vertex Detector– Changes to CILD_01

• Magnetic Field: 4 Tesla• Almost pure Tungsten in HCal

• Background in the Tracking Detectors– “Add-ons” to the Software– Updates to first Results

New Radius for Vertex Detector

• Inner Radius of Beampipe moved to 3cm

• Double Layers– At: 31, 44, 58 mm– Not optimized for

anything

• Detector Model: CILD_01fw

Background in Detector

• Right now:– Only Looking at Incoherent Pairs– Limited Statistics (<1 BX, 300k particles)– “Proof of Principle”

• Want to know:– how much Background there is– where it is coming from

• Using:– Mokka, Marlin (for reading LCIO files)

Where is the Background coming from?

• Incoherent Pairs coming from Vertex– But they can backscatter

into the Tracking Detectors– Standard Mokka Trackers

in most cases only save the Parent Particle (coming from the IP)

– Add sensitive Layers in front of possible backscatter origins:

• LumiCal, BeamCal, Final Focus Quadrupole (QD0)

• Made parts of the beam pipe sensitive

Sensitive Layers

• Only thin sheets of surrounding Material (Air)– Not changing the physics in the simulation– Just a point for Mokka to write out all particles

that pass through– Well maybe sometimes the parent of the

particles is attributed to the hit (not sure)

Hits in the Tracking Detectors

From: A. Savoy‐Navarro, TILC09

Projections (New)

Hits in the Tracking Detectors

• All the hits in the Tracking Detectors caused by the Incoherent Pairs

• Colored Points show, where the Background came from supposedly

• Identification of Source using all generations back to the first particle

Hits in the Tracking Detectors

• All the hits in the Tracking Detectors caused by the Incoherent Pairs

• Colored Points show, where the Background came from supposedly

• Identification of Source using all generations back to the first particle

Origins of the Hits

Identification not Perfect

• Here the “Vertex” of the particles causing the hits are shown

• E.g.: Some Particles originating near BeamCal (QD0) are not attributed to it

• Good Thing: Some Particles from IP are Identified to have hit LCal etc.

• Using parent particles almost all particles seem to be correctly attributed to their origin

Identification not Perfect

• Here the “Vertex” of the particles causing the hits are shown

• E.g.: Some Particles originating near BeamCal (QD0) are not attributed to it

• Good Thing: Some Particles from IP are Identified to have hit LCal etc.

• Using parent particles almost all particles seem to be correctly attributed to their origin

Projections

Stacked

When do the Hits occur

• Some Hits caused by particles directly coming from IP

• Second wave from Backscatters

• Agrees with identification of source

Hits in the VXD

• Some 700 Hits in the inner Double Layer

• Roughly 0.02 hits per mm² and BX

• Were less hits for the 4 Tesla simulation

With and Without Graphite

That’s all!

Projections (old)