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Sensor Choice

Sensor Choice. The story here is surely damage See that silicon worked well in the PLT test until we shifted the timing to optimize diamond Reducing BX “leakage” in diamond increased it for silicon Timing is adjustable for 4 telescopes at a time so we were stuck

josephine-gilbert
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Sensor Choice

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  1. Sensor Choice • The story here is surely damage • See that silicon worked well in the PLT test until we shifted the timing to optimize diamond • Reducing BX “leakage” in diamond increased it for silicon • Timing is adjustable for 4 telescopes at a time so we were stuck • Assumehave same timing issues in a hybrid system • What sort of fluence do we expect for the PLT up to LS2? • Cooled sensor/ROC (0C) work well up to 1.5e15 • From irradiation/tests/test beam studies W. Johns Pixel Luminosity Telescope ECR

  2. Fluence estimate from Simulation • Diamond PLT: 1.6 tracks in 8telescopes/BX @r=4.9 cm, z=175 cm (assume 2835 BX at 1e34/(cm2s)) • 6.4e11/fb so Silicon expect 2.6e12/fb from tracks • ~500/fb to reach 1.5e15 • Try to scale to something we know… (FPiX inner) • Will get a little more due to conversions, use middle radius of FPiX to be conservative in scaling • Scaling estimation from unoffical dose/fluence calculator (charged hadrons) • r = 10 cm, z = 34.5 cm: 1.2e12/(cm2fb) FPiX • Lowball inner FPiX radius (~layer 3 of barrel) • r = 4.9 cm, z = 175 cm: 3.1e12 /(cm2fb) PLT • Ratio for comparison: PLT sees ~3X damage of the FPiX inner disk • Now we can try to compare to a measurement.

  3. Fluence/aging estimate • PLT sees damage at about the same rate as the current Pixel Layer 1 • This lets us compare to the upgrade too (Leakage Current / ROC at the end of 2012 from G. Bolla) BPiX FPiX (Scales adjusted so BPiX is x3 FPiX)

  4. Upgrade Layer 1 expected to go ~250/fb Upgrade Layer 1 Current Layer 1

  5. Fluence/aging estimate • PLT is about the same as the current BPiX layer 1 • Layer 1 damage has been projected using the Hamburg Model (Bias V needed for 99% efficiency) (Dec 2012 plot from Seth Zenz) PLT Power Supply Limit LS2? Looks a bit pessimistic PLT starts here

  6. Fluence/aging estimate • PLT is about the same as the current BPiX layer 1 • Comparing to the Upgrade TDR Layer 1 (x2 Fluence over current Layer 1) suggests PLT lasts a long time • Upgrade TDR used 2 sensor temperatures 0 C and (-4 C) • Replacement of Upgrade layer 1 at 250/fb • Upgrade layer 1 sees about 2x fluence of Current Layer 1 • 250/fb: fluence of 1.5e15, current: 47mA (27mA), (600 V max) • (PLT x5 less current: 3 sensors not 16 sensors) • Sensor still operates at 3.0e15, but resolution etc. will suffer • Higher temperature will damage faster • Seems the critical factor for PLT • PLT HV can go to 500 V, and 10 mA now • Conservative assumption (x2) is PLT can go 250/fb too

  7. Why 250/fb, 500/fb? Luminosity is coming • By LS3 2e34 y cm-2s-1 (50 ns Bx spacing?) • By LS2, ~250/fb? We actually ended the 2012 running at a higher Luminosity than predicted here (& 50 ns Bx spacing) • From European Strategy Preparatory Group Sept 2012

  8. Won’t the PLT suffer at high rate? • It’s not just the particle rate, it’s the trigger rate The dominant loss mechanism of the PSI46v2 (analog) is the reset of the Double Column The PLT is read out at a much lower rate than the CMS L1A At CASTOR we found a few kHz gave plenty of data -This gives only a small inefficiency in the readout -Less of an effect for the column sum (Fast Or) ~4 kHz ~0.5% Nucl.Instrum.Meth. A581 (2007) 343-346 0% Will be important to do custom studies to monitor inefficiencies.

  9. What about the AOH? • The innermost AOH sits at about 11 cm from the beam and at about 180 cm in z • Fluence is about x3 less than for the sensor according to the same simulation as shown earlier This is 500/fb Hard to compare to BCM AOH since it was uncooled. This plot assumes -10C. The AOH should last a long time for PLT

  10. Other chips: SEU troubles? • LLD, DOH, delay25, tpll, etc. • Not a lot to compare to since current pixel components are at ~10 times less fluence • But pixels have way more than x10 components than PLT: should be ok • TBM • About same fluence as current layer 1 • Same argument, pixels have way more TBMs and bad SEU rate is low in pixels, 1/hr, maybe PLT sees one every few fills • ROC • Need to monitor and reset if a DC etc. falls out • We’ve seen this once in CASTOR

  11. Conclusions • The PLT sensor should last 250-500/fb • The AOH looks like it should last 250-500/fb • Other chips SEU rate is small and should be rare in a fill • Damage rate for sensors and AOHs is dependent on temperature, we should revisit when we know more about cooling • Mitigation strategies: • Damage: PLT components are easy (comparatively) to replace/upgrade if the pixel volume is open • SEU: monitoring and corrective action

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