Proposal for a Global Numbering Scheme in Belle II SVD: Overview and Discussion
This document summarizes a recent meeting focused on the numbering scheme for the Belle II Silicon Vertex Detector (SVD). Key points include discussions on the SVD2 scheme, with contributions from Hara-san and Tsuboyama-san, and a proposal for a cohesive global numbering concept. Markus Friedl presents his views on layer, ladder, and sensor numbering while comparing it with simulation approaches from Christian Oswald. Hardware constraints related to sensor readout directions and origami sensors are also discussed, emphasizing compatibility with existing structures and the need for software adjustments in certain configurations.
Proposal for a Global Numbering Scheme in Belle II SVD: Overview and Discussion
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Presentation Transcript
SVD NumberingScheme Markus Friedl (HEPHY Vienna) SVD Meeting
Introduction • The Belle II numberingscheme was a topicat last week‘s IDM • Hara-sanandTsuboyama-sanexplainedthe SVD2 scheme • Generally, thewishof a global numberingconcept was expressed • Ushiroda-sandistributedBelle II Coordinate System and Numbering Scheme document draft yesterday • Same scheme as SVD2 Markus Friedl (HEPHY Vienna)
Hara-san Markus Friedl (HEPHY Vienna)
My Opinion • Wearefreetochooseanynumberingschemeforlayers, laddersandsensors (thoseare all independent) • 2. Layers: I proposed 3…6 (insideto outside, increasing r) toavoidconfusionwith PXD 4 (Hara-san: 0…3) • 3. Ladderswithinonelayer: not definedyet, noproblemtofollow SVD2 scheme (inreasing) 4 • 4. Numbering in z from +z towards –z: not definedyet, but seems non-natural (intuitively, I wouldexpectincrasing z) 8 … but let‘swait – I maychangemymindlater;-) • 4= consistentwith Hara-san • 8= disagreementwith Hara-san Markus Friedl (HEPHY Vienna)
Comparisonwith Simulation • Christian Oswald (previouslyPrague, now Bonn) toldushisnumberingschemefor SVD simulation: • 2. Layers: 3…6 (insideto outside) 4 • 3. Couldn‘tsay, but presumably OK 4 • 4. Numberingtowards positive z 8 • Weconcludethat Christian apparentlyusesthe same approach (numberingincreasingwithcoordinates) which I wouldexpect • Why z isopposite: numberingdoes not follow z, but • is 0 at +z and at -z Markus Friedl (HEPHY Vienna)
Hardware Constraints • The sensorreadoutdirectionisdefinedbythe APV25 0 127 APV25 Markus Friedl (HEPHY Vienna)
OrigamiSensor (n-side) • n-side (facing CDC), seenfrom outside (CDC) Markus Friedl (HEPHY Vienna)
OrigamiSensor (p-side) • p-side (facing beam pipe), seenfrom outside (CDC) • Strips areactuallybehinddrawing plane Markus Friedl (HEPHY Vienna)
WedgeSensor (n-side) • n-side (facing CDC), seenfrom outside (CDC) 127 #3 0 127 #2 0 127 #1 0 127 #0 0 0 511 Markus Friedl (HEPHY Vienna)
WedgeSensor (p-side) • p-side (facing beam pipe), seenfrom outside (CDC) • Strips and hybrid areactuallybehinddrawing plane 0 0 #0 127 #1 #2 #3 #4 0 #5 127 767 Markus Friedl (HEPHY Vienna)
RectangularEdge Sensor (n-side) • n-side (facing CDC), seenfrom outside (CDC) Markus Friedl (HEPHY Vienna)
Rectangular Edge Sensor (p-side) • p-side (facing beam pipe), seenfrom outside (CDC) • Strips and hybrid areactuallybehinddrawing plane Markus Friedl (HEPHY Vienna)
FullLadder – EverythingTogether • Bothsidesseenfrom outside – n-sidethroughsensors • Almostentirelycompatiblewith Hara-sanscheme! 4 8 4 Thereisnohardwaresolutionhere, wehavetoflip in software 4 4 4 Markus Friedl (HEPHY Vienna)
Summary • Global Belle II numberingschemeproposed • LocalstripnumberingisdeterminedbytheAPV25 • Bychance, the APV25 stripnumbering in ourconfigurationisalmostfullycompatiblewiththeproposednumberingscheme! • Only p-sideofrectangularedgesensorsneedtobeflippedatsomepoint in software • Simulationshouldflip z countingdirectionandmakesurefstartsat (x,y,z)=(1,0,0) accordingtothe B2 Note draft • ShallwerenameSVD layers(presently 3,4,5,6) to 0,1,2,3 ? (Couldcreatesomeconfusion…) Markus Friedl (HEPHY Vienna)