1. Status of HGL R&D collected significant test beam/cosmic data –analysis in progress (Chunhui, Hongkai) –preliminary results: good linearity energy resolution: 2x worse compared to simulation, but possibly sufficient for strawman design(?) narrow shower distribution (R M ≈ 11 mm) –open questions: calibration (sensor sensitivities, gaps/overlaps, non- linearity,…?) description by MC (cluster size, charge diffusion, …) 1

2. Linearity reasonably good linearity –no obvious effect of saturation absolute calibration: –needs charge sharing in simulation –calibration with MIPs not consistent 2

3. Energy Resolution resolution ≈2x worse compared to simulation –different sensor sensitivities not fully corrected –relative calibration: how? so far: single correction factor per sensor to minimize resolution 3

4. Shower Profiles very narrow distributions not yet fully described by simulation –GEANT simulation does not include charge diffusion look at hit density and cluster density in data 4

5. Cluster Sizes simple charge diffusion model can describe cluster size for MIPs –average cluster size ≈ 2-3 doesn’t match average cluster size in showers –absolute calibration factor cluster size appears to vary with hit density interplay of –merging of clusters –larger clusters for larger angles –relative admixture of noise clusters –…? need better modeling! 5

6. Summary on Prototype R&D demonstrated satisfactory basic properties –good linearity, narrow shower distributions next steps need better microscopic understanding –modeling of charge diffusion under way info will be used in more advanced studies –calibration methods –model of showers –particle ID –… 6

7. Next Steps on CMOS Sensor need further development of ITS upgrade chip first studies of data volume/bandwidth have been done (Adam Szczepankiewicz) –baseline design for ITS not sufficient, need dedicated R&D –to be continued new CMOS sensor based on ITS chip needed for Mini-FoCal –chip designer manpower available? (BARC?) 7

8. General Time Schedule 8

9. Urgent Issues internal LoI for summer, start preparation of LoI for LHCC directly after –need simulation manpower asap (Marco, Joern, …, IIT Mumbai, …?) –editorial group (Thomas, …?) preparation of Mini-FoCal –setup hardware design team –coordinate LGL efforts (beam test) –more activity on HGL technology: CMOS sensor R&D 9