1. CALICE Referees’ Review Andy White, Junji Haba DESY – PRC 71 April 2011

2. Very good overview from PRC68 CALICE is a large, worldwide collaboration working on many aspects of PFA-based calorimetry with fine sampling /granularity for a future linear collider Impressive test beam program for several years CALICE gives a precise picture inside Shower (antomy) Publications starting to appear…important for proposals, future support,…  Good progress

4. CALICE overview cont’d New dimension added: potential calorimetry for CLIC ECAL’s : Si-W, Sc-W, DECAL HCAL’s: AHCAL, RPC-DHCAL, GEM-DHCAL, GRPC- SDHCAL, Micromegas-SDHCAL and WHCAL for higher energyJET (T3B) CALICE is still a great “horizontal” collaboration, but with strong involvement from “vertical” detector concepts: “The major part of the effort is focused towards presenting realistic proposals for the detector concept reports of the ILC technological design phase 1, which is due in 2012.” with a few established options. Some other options are yet to be examined in the form of “physics prototype”

5. Ultimate goal of the collaboration: Validation of PFA

6. Beam test is the key To validate/improve the performance. To make 3D “anatomy” of electromagnetic/ hadronic shower with super fine grain sampling calorimeters to get a complete understanding of showers. List of Past campaign

7. Si-W ECAL

8. Hadron response for simulations in W Si-W ECAL Valuable input for Model improvements

9. AHCAL

10. Software compensation works! AHCAL

11. Linearit ≤ 1% Hadrons MC simulations of longitudinal profiles Saturation of photon sensors under control Positron response of AHCAL, non linearity due to PPD can be recovered reasonably well.

12. Digital calorimeter works fine. Blue Full contained DHCAL

13. Combined beam test possible only in CALICE SiECAL+DHCAL

14. Tungsten HCAL for higher jet energy W-AHCAL=AHCAL+W “First Impression”

15. Dynamic anatomy of shower: Timing structure of shower evolutions

16. Toward validation of PFA algorithm Very important step, further study should be extremely useful. PFA

17. Personal proposal (JH) for a thorough extension of the embedding method. Experimental validation of PFA is one of the ultimate goal of CALICE which is yet to be achieved. The vast sample of calorimeter response taken in the CALICE beam test can be a powerful “shower library”. One can construct virtual calorimeter response of “Jet” with the shower library in the computer by an embedding method without any shower simulations. PFA algorithm would demonstrate its ability with the above fully embedded virtual Jet sample. May need more beam test sample for /K/pi/p down to low energy (cut off momentum).

18. Technological prototyping in progress

19. New approach SDCAL Two technologies considered: GasRPC, Micromegas: GRPC

20. Semi-digital HCAL

21. Comments and Recommendations The PRC congratulates CALICE on its very impressive and successful test beam campaigns and supports their continuation with the remaining physics prototypes, and technical prototypes as realistic components of future ILC detectors. The calorimeter technologies developed and investigated are also extremely valuable for any future experiments. The beam test outcome is also very useful for future improvement of our understanding of shower development, which should be essential for any future (and also ongoing like LHC’s ) experiments.

22. The PRC recommends that DESY continue support for: - Necessary modifications to test beam fixtures - Test beam campaigns at CERN and Fermilab - Continuation of electronics integration development - Mechanical and electrical engineering - Provision of computing resources

23. Notes The PRC take note that the challenges for adequate test beam time and the funding necessary to carry out the proposed program. - While at FNAL sufficient time could have been allocated in 2011, the request for CERN was, despite a good preparation and a favourable evaluation by the CERN SPS committee, severely downscaled.

24. Suggestion The effort to improve the shower model is very important and would be done in a systematic and strategic way. We like to encourage it further. It is nice to have the report on the status and future plan for the collaboration with the simulation research activities in future meeting.