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A G A T A 2 nd Prototype Detector. Initial Measurements & Evaluation. Andrew Boston, Matthew Dimmock, Laura Nelson, Sarah Rigby. Overview. Resolutions – Cologne , Liverpool - Values quoted are for single LVDS cable & single channel. Singles scan results.
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AGATA2nd Prototype Detector Initial Measurements & Evaluation Andrew Boston, Matthew Dimmock, Laura Nelson, Sarah Rigby
Overview • Resolutions – Cologne , Liverpool • - Values quoted are for single LVDS cable & single channel • Singles scan results • Initial coincidence scan results • Summary
Liverpool – Resolution Measurements Am – 241
Liverpool – Resolution Measurements Am – 241 • All channels < 1.25keV
Liverpool – Resolution Measurements Am – 241 • All channels < 1.25keV • Variation is a function of capacitance
Liverpool – Resolution Measurements Co – 60 • Most channels < 2.1keV
Liverpool – Resolution Measurements Co – 60 • Most channels < 2.1keV • Resolutions improve by ~0.2keV when all LVDS connected
Cs-137 Singles Fine scan • 920MBq Cs-137 source • 60 sec per position • 1mm steps • 1mm diameter collimator • Max count rate = 720 cps • Background = 40 cps • 600keV CFD threshold • Accepted triggers = 120 cps • 180GB pre-sorted data
Core 662kev – Ring gated • Increased counts at edges – taper
Risetimes – Core 662keV T30 T90 T60 • Fast axis – Lattice orientation
Risetimes – Core 662keV T30 T90 T60 <100> <100> <100> <010> <010> <010> • Fast axis – Lattice orientation
Physical segmentation depth: Collimation gap centred on (w.r.t. crystal base): 90mm 72mm 54mm 83.7mm 36mm 21mm 8mm 65mm 48mm 29mm 13.5mm 2mm 0mm Coincidence Setup Div = 2.1mm Div = 1.5mm
Initial scan – Counts per hour 1.4mm 2.8mm
Initial scan – Counts per hour 1.4mm 2.8mm
Summary • Ongoing off-line singles analysis • Corrected scan setup following initial coincidence scan line • Currently running radial scan across y-axis (4mm steps)
Summary • Ongoing off-line singles analysis • Corrected scan setup following initial coincidence scan line • Currently running radial scan across y-axis (4mm steps) HELP !!!!!!!!
Coincidence Grid Current Plans: Hexagonal or Cubic Grid? Initial Proposal:
Coincidence Grid Current Plans: Hexagonal or Cubic Grid? Initial Proposal: Equidistant points ???