1 Zero Degree Calorimetry for CMS Had EM e +,  - Michael Murray for CMS

2 Schematic Side View of Detector pp Lum EMHad PMTs Lead/ plastic Fiber 1.5cm tungsten plates 2mm plates ,  o N Space for flow upgrade Light guide Copper frame to take heat out 74 cm Lum data available in HLT & offline

3 We are at Z =  140m inside the TAN just behind the “pair of pants.” Where we sit Warm Dipole

4 Acceptance at TAN, Z=140m 88 mm 111 mm For a crossing of 140  Rad Py =  2.78 GeV Px+ = 1.22 GeV Px- = 3.18 GeV 2cm shift Acceptance starts  = 8. 1 and is 100% for  > mm Active area Beam divergence of 30  Rad Beam center ~ 90mm from center of TAN

5 A PMT’s view of the fibers

6 We tested the full electronic configuration. The pulse shape after 204m of cable was as expected & the splitting at the 2nd patch panel worked well. We ran with and without reference cables and did not see a significant degradation. Therefore we have decided to lay 9 signal cables + 1 spare in tunnel. These have been laid in the tunnel. 204m signal cable Patch panel CMS electonics PMT by ZDC Tunnel Counting Room Time Voltage reference cable Two cables/PMT 2m cable Patch Panel & split Front End Electronics

7 EM1 EM2 EM3EM4EM5 beam Had1 Had2 Had3 Had4 ~16mm Schematic of Beam Test Motorized X, Y Table

8 20 GeV, positrons 17.59% Response to Positions 20 GeV ADC ADC=  tubes g i Adc i 50 GeV 100 GeV Each tube has gain g i

9  =22%  =25% 150 GeV 300 GeV Hadronic Response ADC Counts

10 Goals for Summer Checkout ZDC with laser/LED Connect to HCAL DAQ system Get monitoring and detector safety and control systems Connect to luminosity servers Look for beam-gas interactions with one-beam When we have 2 beams look for interactions Participate in Van der Meer scans If we get very luck this year try to make a measurement of pp => Neutron + X, as was done at RHIC