Irradiated 3D sensor testbeam results Alex Krzywda On behalf of CMS 3D collaboration Purdue University March 15, 2012

Overview We perform tests on detectors inside the Test Beam facility at FNAL (and also in our lab at Purdue). Results shown are from January Test Beam. Analysis and results are shown for two 3D sensors, 1E_4 and 4E_13, irradiated to the fluence of 1E14 p/cm 2 2

FNAL Test Beam We place the DUT (Device Under Test) inside a telescope with 8 good planar FPIX plaquettes 3

Telescope Planes 4 8 telescope planes – four 2x3 and four 2x4 plaquettes Planes are rotated 25°, with respect to 100μm pixel pitch direction, for more charge sharing (better position resolution)

Data Analysis 5 Data integrity Track reconstruction Allowed cuts: 1.Chi2/NDF <= track/event 3.8 planes hit/event - Sigma ~19 μm - Mean is offset (alignment not perfect) Telescope plane residual -Total track resolution (using residuals from all telescope planes) is normally < 10 μm

Lab IV tests 6 2E was not placed in beam due to unstable current behavior

1E_4 (Φ = 1E14 n eq /cm 2 ) - Irradiated Charge distribution for all clusters 7 Landau convoluted Gaussian fit We use clusters of size 2 pixels to determine position resolution (sigma or RMS) clusters of size 1 pixel resolution = (pixel pitch)/sqrt(12) Larger clusters = more charge sharing = better position resolution

4E_13 (Φ = 1E14 n eq /cm 2 ) - Efficiency 8 2D Efficiency plot for sensor 4E132D hit map for sensor 4E13 ~60% efficiency (for this run) Plane efficiency = 1 if constructed tracks are within a set window around its corresponding hit on that plane

1E_4 (Φ = 1E14 n eq /cm 2 ) - Efficiency 9 ~74% efficiency (for this run) Greater efficiency than 4E_13 can be due to: 1.Better DAQ settings 2.Less noise 3.Better alignment 2D Efficiency plot for sensor 1E42D hit map for sensor 1E4

1E_4 (Φ = 1E14 n eq /cm 2 ) – Position resolution 10 1-pixel residuals are found when a particle hits only one pixel (no charge sharing between pixels) Expected resolution is (pixel pitch)/sqrt(12)  binary resolution These results include track resolution through telescope, thus a few microns higher than expected X-direction has 100 μm pitch Y-direction has 150 μm pitch

1E_4 (Φ = 1E14 n eq /cm 2 )– Bias scan Follows expected upward trend. Slight plateau around 20-25V. 11 Plateaus around full depletion, because statistics increase up to that point (better Gaussian). 11

4E13 Φ = 1E14 n eq /cm 2 – Bias scan 12 In this case statistics were fine throughout, but no improvement We actually see a slight increase due to larger electric field inside pixels.

Summary 13 Testbeam data analysis consists of Track reconstruction Telescope alignment Position resolution on DUT by Monicelli software developed by Milano group (D. Menasce et al.) data analysis performed for two irrradiated (Φ = 1E14 n eq /cm 2 ) 3D sensor data taken during the January 2012 testbeam at FNAL Negligible signal loss after Φ = 1E14 n eq /cm 2  expected Clusters are mostly size 1 pixels (no charge sharing) Thus, binary resolution (~30 um for 100 um pitch and 43 um for 150 um pitch) In cluster of size 2 pixels (charge sharing)  very low statistics um resolution for both 100 and 150 um pitches due to Poor telescope alignment and Telescope plane position resolution Track efficiency is lower than expected

Next plans 14 Analysis Perform analysis with Best tracks with a resolution of ~5 um-> anticipates very low statistics Merge identical runs for more clusters of size 2 pixels -> increase statistics Testbeam Take data during March 2012 testbeam with DUTs rotated Scan angles: 10°, 15°, 20°, 25°, and 30° To increase charge sharing Good DUT cooling Good DUT calibration Collect data with best bias and threshold values