UM PPS Lab Activities

PPS meeting January 22, 2012Claudio, Curtis, Dan, Riley

UM PPS Activities 2

Panel Structure• Two lead glass (% Pb?) substrate separated by glass

beads mixed with the solder glass (frit)• 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, 2013

UM PPS Activities 3

Large Pitch Panels• Glass thickness ~ 0.088”mm = 2.23 mm• Gas gap Measured 0.195”-2·0.088” = 483μm (450-500 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 = 14.18 cm3

February 19, 2013

13.5”=343 mm

12.8125”=325.4 mm3.5”

=88.

9 m

m

4.06

25”=

103.

2 m

m

3.2”

=81.

3 m

m

13”=330.2 mm

UM PPS Activities 4

Large Panels Cell

February 19, 2013

Anode (RO) Pitch 0.1”=2.54 mmElectrode 0.5”~1.27 mmSpace 0.5”~1.27 mm

Cathode (HV) Pitch 0.1”=2.54 mmElectrode 0.55”~1.397 mmSpace 0.45”~1.143 mm

A(crossing):0.05” ˣ 0.055’=1.774 mm2

A(die): π·(0.05/2”)2=1.267 mm2 (~71) Packing factor =(Across+Adie)/2 * 1/Pitch2 ~23.5%

3 Vishay (VP1-3) + 2 Babcock (BP1-2) Ni-SnO2 VP1 &VPC cracked8 Vishay (VPA-E + F,G,H unused yet) Ni-Ni (VPD in Tel Aviv)

UM PPS Activities 5

Mid-size Pitch Panel• Glass thickness Top & Bottom 0.088” = 2.23mm• Gas gap: Vishay document ~ 0.0116” = 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 cm3

February 19, 2013

- - - - - - - - - - - - - - - - 175 mm - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 169 mm - - - - - - - - - - - - - - - - - - -

- - - - - - - - - - - - 135 mm - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - 131 mm - - - - - - - - - - - - - - -

- - - - - - - - - - - - - - - - - - - - 167 mm - - - - - - - - - - - - - - - - - - -

- -

- - 6

5.0

mm

- - -

-

- -

- - 7

0.0

mm

- - -

-

- -

- - -

- 86.

6 m

m -

- - -

- -

UM PPS Activities 6

Mid-Size Panel Cell

February 19, 2013

Anode (RO)Pitch 0.04” = 1.016 mmElectrode 0.0281”~0.714 mmSpace 0.0119”~0.302 mm

Cathode (HV)Pitch 0.04” = 1.016 mmElectrode 0.0174”~0.442 mmSpace 0.0226”~0.574 mm

A(crossing):0.0281” ˣ 0.0174”=0.315 mm2 A(die): (0.02”)2=0.258 mm2 (~82%)A(effective)=0.02” ˣ 0.0174”=0.224 mm2 (~71%)

Packing factor =<Aeffective>/Pitch2~ 22% (not 64% as in Dan’s estimate intrinsic PDP efficiency higher)

6+6 Vishay (MPx) Ni-SnO2 + 1 old broken ( support)

UM PPS Activities 7

Small Pitch Panel• Glass: Top(Anode)~0.063”=1.6mm Bottom~0.079”=2.0mm• Gas gap Vishay document ~ 0.007” = 178μm Measured 0.0150”-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 mm3

February 19, 2013

10.7mm

10.0 mm

9.8 mm

10.6mm

3.7

mm

2.8

mm

2.4

mm

2.6

mm

UM PPS Activities 8

Small Panel Cell

February 19, 2013

Anode (RO)Pitch 0.024”=0.61 mmElectrode 0.008”~0.203 mmSpace 0.016”~0.407 mm

Cathode (HV) Pitch 0.024”=0.61 mmElectrode 0.014”~0.356 mmSpace 0.010”~0.254 mm Die: Squares 0.014” ˣ 0.014” A(cross):0.008” ˣ 0.0016’=0.0826 mm2 A(effective):0.008” ˣ 0.0014’=0.0723 mm2

Packing factor=Aeffective/Pitch2 =19.4%

6+6 Vishay (SPx) Ni-SnO2

Black lines (between anodes): full length barrier ribs. How toll?

UM PPS Activities 9

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, 2013

UM PPS Activities 10

New Cabinet (Curtis & Riley)

February 19, 2013

Top & sides covered by EMI Static Shield paper + aluminum baseOptical base in place with motorized 2D micrometerRe-design and re-build the mid-size panel support

19”=48.3cm 32.5”=82.5cm

32.5

”=82

.5cm

UM PPS Activities 11

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):

1.7·106hit/20ch 87k hit/ch in 97h ~900 hit/ch·h → <Δ>~±3%

February 19, 2013

UM PPS Activities 12

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 (SnO2 degradation)

February 19, 2013

UM PPS Activities 13

Uniformity Channel Correction• Hit-map channel correction factor: important to verify the

stability of these correction over the 97h of the run

February 19, 2013

UM PPS Activities 14

Uniformity Channel Correction (2)• Correction spread estimate of the error on them: 2-8%

(worse for channels with lower corrections)

February 19, 2013

UM PPS Activities 15

1mm Position Scan Revisited

February 19, 2013

Result ingredients:1) Run Hit-map fit (5 parameters):

N·exp[-(x-μ)2/2σ2] + (mx+q) 2) Line by line corrections from the fit peak amplitude3) Re-fit the corrected hit-map4) Means linear fit on central points5) extra σ(mean)=150μm

3) Gaussian Breit-Wigner (5 par) N/[(x-μ)2+Γ2/4] + (mx+q)0.979±0.002 (Full, no Δy) χ2=139.7/171.003±0.003 (11P, no Δy) χ2=10.83/11

0.981±0.007 (Full with Δy) χ2=11.84/171.005±0.011 (11P with Δy) χ2=0.974/11

UM PPS Activities 16

Line by Line Response

February 19, 2013

UM PPS Activities 17

Corrected Hit Maps Fits

February 19, 2013

Gaussian+LinBreit-Wigner+Lin

UM PPS Activities 18

Parameters

February 19, 2013

Norm Mean

Sigma

Const

Slope Χ2/dofFWHM

UM PPS Activities 19

A Quick Calculation

Theory: σ2data= σ2

intrinsic+ σ2beam

σbeam= 1.1 mm (GEANT)σBW ~ 1.4 mm (FWHM/2.35)σintrinsic = 866 μmBest expectation ~300 μm

February 19, 2013

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)

UM PPS Activities 20

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, 2013