20 April 2004 John Hauptman, Linear Collider Meeting, Paris, 19-23 April 2004

Forward Luminosity Calorimeter Technologies

•SiW - Silicon-tungsten sampling calorimeter (current Si tech)

•Quartz Fiber – Cerenkov longitudinal sampling (CMS HF)

•Gas Cerenkov – Cerenkov longitudinal sampling (new)

•Parallel Plate Avalanche Ch – gas sampling (current)

•PbWO4 – Continuous scintillating (CMS ECAL)

20 April 2004 John Hauptman, Linear Collider Meeting, Paris, 19-23 April 2004

The Problem

• Bunch crossing 1.4 ns• Radiation dose ~100 MRad/y• Pairs produced / crossing ~ 200 TeV <E> ~ 4 GeV

<x,y> ~ several cms • Must see 250 GeV Bhabha e+e-• Must veto 2-gamma background events

20 April 2004 John Hauptman, Linear Collider Meeting, Paris, 19-23 April 2004

Si-W: layers Si ..mm W ..mm(M.Breidenbach, T.Maruyama, …)

Known technology fine granularitywell simulated and understood

Strengths

Weaknesses Si may be radiation-soft electron-hole drift is slow recovery time long

20 April 2004 John Hauptman, Linear Collider Meeting, Paris, 19-23 April 2004

SiW fig

20 April 2004 John Hauptman, Linear Collider Meeting, Paris, 19-23 April 2004

SiW dose

20 April 2004 John Hauptman, Linear Collider Meeting, Paris, 19-23 April 2004

Quartz Fiber Calorimetry(Onel, Winn)

Well understood (CMS-HF)Fast and rad hard

Strengths

Weaknesses

Time spread of signal ~1 ns (almost OK)

Rad Hardness ~1 GRad (almost OK)

20 April 2004 John Hauptman, Linear Collider Meeting, Paris, 19-23 April 2004

20 April 2004 John Hauptman, Linear Collider Meeting, Paris, 19-23 April 2004

CMS-HF Quartz fiber understanding

20 April 2004 John Hauptman, Linear Collider Meeting, Paris, 19-23 April 2004

Quartz Transmission vs. Dose & Dose Rate

Ray Thomas, Texas Tech University – using an electron accelerator

ray.thomas@ttu.edu

20 April 2004 John Hauptman, Linear Collider Meeting, Paris, 19-23 April 2004

20 April 2004 John Hauptman, Linear Collider Meeting, Paris, 19-23 April 2004

Gas Cerenkov

20 April 2004 John Hauptman, Linear Collider Meeting, Paris, 19-23 April 2004

Parallel Plate Avalanche Chamber

• Positive ions too slow ~ micro sec

20 April 2004 John Hauptman, Linear Collider Meeting, Paris, 19-23 April 2004

PbWO4 Crystals

• CMS ECAL … scary numbers of rad h hardness …