Gossip (Gas On Slimmed Silicon Pixels) detector Wilco Koppert

Wilco Koppert2/14 Contents Introduction Gossip Simulations results Gossip Testbeam results

Wilco Koppert3/14 Introduction In a gas filled drift volume electron ion pairs are created along the track of a traversing particle. Due to the E-field electrons drift to the grid and are focussed into the holes. As a results of the strong E-field in the avalanche gap the each single electron causes an avalanche, that is measured by a pixel.

Introduction Advantages: Extremely high radiation tolerance, low material budget Accurate measurements in 3D Low noise, low power, cheap GridPix Detectors Applications: DICE (Delft Internal Conversion Experiment)- detector has a 2cm gas layer: study anomolies in internal conversion spectra. Application of Gridpix in WIMP search with noble liquids Application of Gridpix in neutrinoless double beta decay Candidate detector ATLAS b-layer at the sLHC (Gossip; 1mm gas layer)

Gossip Simulation Results Gossip resolution is dominated by: Diffusion of electrons in gas (~100 μm/√cm) Pixel size (55 μm) Time slewing, time resolution (10 ns ->... ) Configuration simulations: GARFIELD (simulation program for drift chambers) CO2-DME 50:50 Diffusion ~100 um/√cm, ~5-6 electrons/mm Drift Gap 1 mm, Avalanche Gap 50 μm Muons 10 GeV Drift velocity: 55,6 μm/ns Goal: vary time resolution, angles and pixel-pitch and see what we can reach

Gossip Simulation Results Pitch 55um To give a complete picture: The angular resolution is ~ degrees at smaller angles Pitch 1um Fit results with line (x0, y0, Ɵ, ɸ )

Wilco Koppert7/14 Gossip Testbeam results Reality with Argon Isobutane: V d Gossip: 4.8cm/us = 1mm/20.8ns ~2 Timebins → Time slewing dominant XY resolution gossip ~30 um, almost perpendicular tracks Angular resolutions; time info needed... Efficiency to be calculated

Wilco Koppert8/14 To Do Near future: Next testbeam (about now), use same settings as in simulations. Understand differences sims and testbeam Far future: Upgrade to better time resolution Solve time slewing problem

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