ECAL days, 17 June 2014

Andrea Benaglia – SPACAL results

SPACAL with SiO2:Ce

Current EE PbWO4

RM = 2.2 cm 3D W printing??

Moliere radius versus fraction of Tungsten in Cu-W alloy

Colours: correspond to different fiber diametersDifferent points: different fiber spacing

Current EE PbWO4

Xo = 0.9 cm

Colours: correspond to different fiber diametersDifferent points: different fiber spacing

Radiation length versus fraction of Tungsten in Cu-W alloy

3D W printing??

SPACAL with SiO2:Ce

Moliere radius versus fibre spacing for 25%Cu-75%W

Current EE PbWO4

RM = 2.2 cm

SPACAL with SiO2:Ce

Optimal geometry Fiber diameter: 0.8mm-- 1mm‐Distance: 1.4-- 1.6mm‐

Can read off the fibre distances used in the simulation

Radiation length versus fibre spacing for 25% Cu - 75% W

Current EE PbWO4

Xo = 0.9 cm

SPACAL with SiO2:Ce

Optimal geometry Fiber diameter: 0.8mm-- 1mm‐Distance: 1.4-- 1.6mm‐

Resolution versus fibre spacing for 25% Cu - 75% W

SPACAL with SiO2:Ce

Resolution at 1 GeV

Optimal geometry Fiber diameter: 0.8mm-- 1mm‐Distance: 1.4-- 1.6mm‐

Current EE PbWO4

Resolution 20% at 1 GeV(stoch only ??)

Resolution, SPACAL with SiO2:Ce25% Cu – 75% W

Fiber diameter 0.8 mmFiber spacing 1.4 mm

Fiber diameter 1.0 mmFiber spacing 1.6 mm

Inputs: SiO2:Ce Light Yield = 103 photons/MeVInputs: Efficiency = 0.01

Some SPACAL numbers of interest to extract:

• Energy lost in liquid scintillator• Photons emitted by liquid scintillator ‘at source’• Photons lost by exiting capillary to metal surround

• Photons exiting capillary at end (other end mirrored, not mirrored)• Photons exiting capillary at end (other end mirrored, not mirrored) per unit of deposited energy, as a function of z

SPACAL design considerations:

What is actual resolution target in CMS ?

We have learnt that a significant amount of resolution islost due to the upstream tracker material budget

Further deterioration due to pile-up

No point in “over” design- Cost- Time- Complexity- No return Irrespective of the physics targets, can we set an upper resolution limit using the upstream tracker material as the limiter alone ???

Need full CMS SIM to study this with a ‘final’ tracker geometry. Take the current tracker for now ???