1. Outline Electromagnetic showers Shower Development Characteristics of showers Shower Detectors DHCal Design Concept Conclusion

2. Electromagnetic Showers Electrons with energies > 100MeV lose energy almost entirely through bremsstrahlung  e + + e - (Pair Production)

3. e+e+ e+e+ e-e- e-e-  0123

4. Characteristics N(t) = e tln2 t max = ln(E o /E)/ln2 L  E 0 /E Showers are statistical in nature

5. Shower detectors Calorimeters measure the total energy deposited Two types – Electromagnetic and Hadronic t max = 3.9 + lnE o The total energy is measured by counting the number of particles in the shower whose energy exceeds certain value

6. Hadronic Showers Transverse momentum = 350MeV/c Hence hadronic showers are more spread out. Most of the energy dissipated is by ionization losses and secondary protons  o  2  (leading to showers)

7. DHCal

8. From CERN-open-2000-344, A. Sharma

9. Initial design concept for gas amplification DHCAL

10. CERN GDD Group – electron-micrograph of GEM foil hole

11. Conclusion Study of various technologies Construction of mechanical prototypes Construction of multi layer prototype