October 2002US CMS HCAL at BU1 US CMS HCAL Meeting Boston University Vasken Hagopian Florida State University

October 2002US CMS HCAL at BU2 HPD QE & K27 Spectrum

October 2002US CMS HCAL at BU3 Test Beam results

October 2002US CMS HCAL at BU4 QE x K27 Spectrum

October 2002US CMS HCAL at BU5 Conclusions 1.The test beam measurements are not compatible with the QE of the HPD’s. 2.The HPD QE provided by DEP are not standard bi-alkali nor green extended bi-alkali. 3.We need to find out what DEP is actually measuring.

October 2002US CMS HCAL at BU6 HB/HE LED and Laser From Test Beam at CERN in 2002 Nichia blue LED barely excites K27 fluor. The LED light to HPD is mostly scattered blue light. Easy to correct so LED light to HPD should be very similar to megatile. Use green LED that is 2.5 times brighter. (See K. Johnson talk). Green LED at 5 volt and 25 nsec should correspond to over 1 TeV.

October 2002US CMS HCAL at BU7 HB/HE LED and Laser Basic calibration module design is good. Laser distribution has been measured in the lab with splitters and the correct length of quartz fibers. Measurements with Pin Diodes and corrected for HPD. QE of Pin Diode 80%, QE of HPD ~10% with a gain of 2000.

October 2002US CMS HCAL at BU8 Laser system Laser to Calorimeter sector (e.g HB+) to Calibration box to HPD nm UV. Pin1 = 25pC. Pin2 = 3pC, HPD = 30 pC nm with dye laser. Pin1 = 50pC, Pin2 = 6pC, HPD = 60 pC. 3.UV laser to megatile 4 pC. 4.Dye Laser to megatile 0.3 pC.

October 2002US CMS HCAL at BU9 Progress HB Calibration box on hold waiting for VECSEL connection determination. Most optical parts completed. HE Calibration box, first prototype under construction (just completed). HO Calibration box – box dimensions not yet specified.