1. OD Calorimetry Study Update — Z vertex position dependence Jaewon Park University of Rochester MINERvA/Jupiter Group Meeting, May 17, 2006

2. 2 Contents Calibration factor dependency  Beam energy  Theta  Phi  Radial primary vertex position  Longitudinal primary vertex position We want that calibration factor doesn’t change too much

3. 3 Detector geometry and primary vertex position No ECAL, it’s just part of Active target z=0 is set to center of whole detector volume automatically z=0 depends on number of each module. Active target is pretty much like cube Should I consider center of Active target as most probably primary vertex ?  Probably center of upstream half of active target Active target OD-HCAL DS-HCAL DS-ECAL Nuclear target 149.46cm87.45cm135.09cm73.08cm 243.9cm 212.85cm

4. 4 Longitudinal primary vertex dependence There’s some variation of resolution Mean shift didn’t change much Cut efficiency decreases as ID distance reduces

5. 5 Comparison with radial offset Resolution variation has similar pattern Calibration factor and cut efficiency are very sensitive to radial primary vertex position

6. 6 Looking at QE data - primary vertex position In the QE configuration file, VERTEX 75. 0. 0. -119. 0 it means event will be generated randomly within a cylinder r=75cm, (x,y)=(0,0), -119<z<0 Z distributes evenly Larger radial distance has bigger contribution  Most of event will be best-or-worst resolution and calibration when particle goes to OD-HCAL

7. 7 Looking at QE event data - theta distribution Neugen events Estimate how much proton will hit DS- HCAL  40-50% More accurate number can be obtained from direct simulation