UM PPS Lab Activities PPS meeting January 22, 2012 Claudio, Curtis, Dan, Riley

Panel Structure Two lead glass (% Pb?) substrate separated by glass beads mixed with the solder glass (frit)solder glassfrit Dielectric posts and ribs could also affect the gap (Vishay Sr. Product Engineer statement) Cathode strips covered by a layer of insulator (how thin/thick?) Pixel cathode size & shape in CAD drawing topdie layer Actual pixel slightly smaller due to dielectric slumping (Vishay Sr. Product Engineer statement) February 19, 2013UM PPS Activities2

Large Pitch Panels Glass thickness ~ 0.088”mm = 2.23 mm Gas gap Measured 0.195”-2·0.088” = 483μm ( μm) Long side (HV): 128 lines in 12.8”  pixel pitch ~0.1”=2.5mm Short side (RO): 32 lines in 3.2”  pixel pitch ~0.1”=2.5mm Gas Volume: 330.2mm x 88.9mm x 0.483mm = cm 3 February 19, 2013UM PPS Activities3 13.5”=343 mm ”=325.4 mm 13”=330.2 mm

Large Panels Cell February 19, 2013UM PPS Activities4 Anode (RO) Pitch 0.1”=2.54 mm Electrode 0.5”~1.27 mm Space 0.5”~1.27 mm Cathode (HV) Pitch 0.1”=2.54 mm Electrode 0.55”~1.397 mm Space 0.45”~1.143 mm A(crossing):0.05” ˣ 0.055’=1.774 mm 2 A(die): π·(0.05/2”) 2 =1.267 mm 2 (~71) Packing factor =(A cross +A die )/2 * 1/Pitch 2 ~23.5% 3 Vishay (VP1-3) + 2 Babcock (BP1-2) Ni-SnO 2 VP1 &VPC cracked 8 Vishay (VPA-E + F,G,H unused yet) Ni-Ni (VPD in Tel Aviv)

Mid-size Pitch Panel Glass thickness Top & Bottom 0.088” = 2.23mm Gas gap: Vishay document ~ ” = 294μm Measured 188” – 2·0.088” = 0.012” = 305 μm 128 (HV) ˣ 40(RO) lines Long 128 lines in 131/167 mm  pitch: pixel~1mm connector=1.3mm Short 64 lines in 65/81.5 mm  pitch: pixel~1mm connector=1.3mm Gas Volume: 160mm x 80mm x 0.3mm = 3.84 cm 3 February 19, 2013UM PPS Activities5  mm   mm   mm   mm   mm 

Mid-Size Panel Cell February 19, 2013UM PPS Activities6 Anode (RO) Pitch 0.04” = mm Electrode ”~0.714 mm Space ”~0.302 mm Cathode (HV) Pitch 0.04” = mm Electrode ”~0.442 mm Space ”~0.574 mm A(crossing):0.0281” ˣ ”=0.315 mm 2 A(die): (0.02”) 2 =0.258 mm 2 (~82%) A(effective)=0.02” ˣ ”=0.224 mm 2 (~71%) Packing factor = /Pitch 2 ~ 22% (not 64% as in Dan’s estimate  intrinsic PDP efficiency higher) 6+6 Vishay (MPx) Ni-SnO old broken (  support)

Small Pitch Panel Glass: Top(Anode)~0.063”=1.6mm Bottom~0.079”=2.0mm Gas gap Vishay document ~ 0.007” = 178μm Measured ”-0.063”-0.079=0.008”=203μm 160(HV) ˣ 40(RO) lines Long 160 lines 10.6/9.8 mm  pitch: pixel~0.6 connector=0.66mm Short 40 lines 2.4/2.6 mm  pitch: pixel~0.6 connector=0.65mm Gas Volume: 10mm x 2.8mm x 0.2mm=5.6 mm 3 February 19, 2013UM PPS Activities7 10.7mm 10.0 mm 9.8 mm 10.6mm

Small Panel Cell February 19, 2013UM PPS Activities8 Anode (RO) Pitch 0.024”=0.61 mm Electrode 0.008”~0.203 mm Space 0.016”~0.407 mm Cathode (HV) Pitch 0.024”=0.61 mm Electrode 0.014”~0.356 mm Space 0.010”~0.254 mm Die: Squares 0.014” ˣ 0.014” A(cross):0.008” ˣ ’= mm 2 A(effective):0.008” ˣ ’= mm 2 Packing factor=A effective /Pitch 2 =19.4% 6+6 Vishay (SPx) Ni-SnO 2 Black lines (between anodes): full length barrier ribs. How toll?

New Panel EMI Shield Aluminum shield for PDP signal testing (HV) 24” long ˣ 12” wide ˣ 16” high Corners: 1.5” Al-extrusion + Copper tape (to be applied) Top/Bottom: EMI Static Shield paper (holes for cables...) February 19, 2013UM PPS Activities9

New Cabinet (Curtis & Riley) February 19, 2013UM PPS Activities10 Top & sides covered by EMI Static Shield paper + aluminum base Optical base in place with motorized 2D micrometer Re-design and re-build the mid-size panel support

Another MP1 Uniformity Run Sudden end: the lab computer died for unknown reasons Hit-map: higher response closer to the HV (smaller gap?) Large variation: ± 50% (±20% on older runs, on used lines) Similar shape for the 97 hourly hit-maps (inside errors): 1.7·10 6 hit/20ch  87k hit/ch  in 97h ~900 hit/ch·h → ~±3% February 19, 2013UM PPS Activities11

Uniformity Run in Time In 97 hours the rate decreases by a factor ~2.5, with an initial jump in the first hour (new lines)! Same behavior is found for every channel points to a single line property (SnO 2 degradation) February 19, 2013UM PPS Activities12

Uniformity Channel Correction Hit-map  channel correction factor: important to verify the stability of these correction over the 97h of the run February 19, 2013UM PPS Activities13

Uniformity Channel Correction (2) Correction spread  estimate of the error on them: 2-8% (worse for channels with lower corrections) February 19, 2013UM PPS Activities14

1mm Position Scan Revisited February 19, 2013UM PPS Activities15 Result ingredients: 1) Run Hit-map fit (5 parameters): N·exp[-(x-μ) 2 /2σ 2 ] + (mx+q) 2) Line by line corrections from the fit peak amplitude 3) Re-fit the corrected hit-map 4) Means linear fit on central points 5) extra σ(mean)=150μm 3) Gaussian  Breit-Wigner (5 par) N/[(x-μ) 2 +Γ 2 /4] + (mx+q) 0.979±0.002 (Full, no Δy) χ 2 =139.7/ ±0.003 (11P, no Δy) χ 2 =10.83/ ±0.007 (Full with Δy) χ 2 =11.84/ ±0.011 (11P with Δy) χ 2 =0.974/11

Line by Line Response February 19, 2013UM PPS Activities16

Corrected Hit Maps Fits February 19, 2013UM PPS Activities17 Gaussian+Lin Breit-Wigner+Lin

Parameters February 19, 2013UM PPS Activities18 NormMean Sigma Const Slope Χ 2 /dof FWHM

A Quick Calculation Theory: σ 2 data = σ 2 intrinsic + σ 2 beam σ beam = 1.1 mm (GEANT) σ BW ~ 1.4 mm (FWHM/2.35)  σ intrinsic = 866 μm Best expectation ~300 μm February 19, 2013UM PPS Activities19 The width of the measured distribution could be larger because of: Ionization starts inside the gas O(100 μm)  larger beam spread Systematic: misalignment slit-panel line, correction, fit function,... The simulation could underestimate the spread because of Extra material after glass (dielectric and/or electrode) Glass composition Photon contribution (only betas simulated)

Conclusions Positive impression on February 6 DoE lab tour (15’): very short introduction + two experiences and one animation A lot of preparation work in the lab:  Panel geometry much more clear  New cabinet and EMI shield ready  Work on filling and testing our gas bottles  Wiener readout code now running in our dedicated lab laptop The uniformity run on new lines shows a severe degradation of the rate as a function of time and a large channel by channel variation (total ± 50%), but quite stable in time The position scan runs fitted with a Breit-Wigner (GEANT simulation best fit) seems to be better than Gaussian. To estimate the intrinsic resolution we need to understand the limitations of the simulation and the systematic errors involved in our data taking February 19, 2013UM PPS Activities20