Forward Luminosity Calorimeter Technologies

1. 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) John Hauptman, Linear Collider Meeting, Paris, 19-23 April 2004

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

3. Si-W: layers Si ..mm W ..mm(M.Breidenbach, T.Maruyama, …) • Known technology • fine granularity • well simulated and understood Strengths Weaknesses • Si may be radiation-soft • electron-hole drift is slow • recovery time long John Hauptman, Linear Collider Meeting, Paris, 19-23 April 2004

4. SiW fig John Hauptman, Linear Collider Meeting, Paris, 19-23 April 2004

5. SiW dose John Hauptman, Linear Collider Meeting, Paris, 19-23 April 2004

6. 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) John Hauptman, Linear Collider Meeting, Paris, 19-23 April 2004

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

8. CMS-HF Quartz fiber understanding John Hauptman, Linear Collider Meeting, Paris, 19-23 April 2004

9. Quartz Transmission vs. Dose & Dose Rate Ray Thomas, Texas Tech University – using an electron accelerator ray.thomas@ttu.edu John Hauptman, Linear Collider Meeting, Paris, 19-23 April 2004

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

11. Gas Cerenkov John Hauptman, Linear Collider Meeting, Paris, 19-23 April 2004

12. Parallel Plate Avalanche Chamber • Positive ions too slow ~ micro sec John Hauptman, Linear Collider Meeting, Paris, 19-23 April 2004

13. PbWO4 Crystals • CMS ECAL … scary numbers of rad h hardness … John Hauptman, Linear Collider Meeting, Paris, 19-23 April 2004