1. Test-beam Results for the CMS Forward Pixel Detector Carsten Rott Daniela Bortoletto, Gino Bolla, Amitava Roy Purdue University 28 April 2001

2. Test-beam Results for the CMS Forward Pixel Detector Carsten Rott Daniela Bortoletto Gino Bolla Amitava Roy Purdue University 28 April 2001

3. Pixels/blade 24 Blades/disk The CMS Detector APS 2001 C. Rott Barrel + Forward Pixel Disks FPIX-Disk

4. The Pixel Detector 150  m x  m pixel thickness 270  m 22x30 pixel array rad. hard DMILL ROC APS 2001 C. Rott

5. Telescope   Beam Si-Strips vertical Si-Strips horizontal Scint. Counters   X/Y-Fibers 1mm Dia. few mm 2 Extrapolated track  x = 2.0  m  y = 3.6  m  Pixel Detector and Repeater Card APS 2001 C. Rott 250GeV/c pion beam Repeater card can be rotated Can trigger on region as. small as 1mm 2

6. Charge sharing comparison Charge sharing between rows (rotated by 20 o ) Charge sharing between rows (not rotated) 150  m APS 2001 C. Rott PH is 12bit ADC value Charge sharing is increased by rotating the sensor Charge sharing can be used to improve the resolution

7.  distribution Position correction curve APS 2001 C. Rott  is the difference of the fraction of charge deposited in the neighboring pixel A is a normalization factor  vs position ( 20 o rotation angle)

8. Resolution Resolution in micron between rows (rotated by 20 o ) Resolution in micron between rows (not rotated) APS 2001 C. Rott

9. Resolution APS 2001 C. Rott 0 0 rotation 20 0 rotation Highest resolution for large charge sharing and hits in between pixel

10. Signal height: Noise: Signal to noise ratio of 60 S/N and Efficiency APS 2001 C. Rott An absolute efficiency could not be measured because of a time stamp problem. A strong correlation between tracked position and pixel hit position, suggests high efficiency.

11. Conclusions Charge sharing can improve the resolution Resolution at 20 0 rotation 10-20  m Resolution at 0 0 rotation 10-50  m Resolution is position dependent S/N = 60 High efficiency APS 2001 C. Rott http://www.physics.purdue.edu/cdf/pixels/csem/index.htm