Samir Arfaoui Digitisation parameters 14 March 2013 2 6 main parameters charge distribution slope1 00678 charge distribution slope2 0671 ratio of contribution from slope1 slope2 0345 ID: 1007073
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1. W-DHCal Simulation StatusSamir Arfaoui
2. Digitisation parameters14 March 201326 main parameterscharge distribution slope1 = 0.0678charge distribution slope2 = 0.671ratio of contribution from slope1, slope2 = 0.345 (???)threshold [pC] = 0.3645distance cut [unit?] = 0.092charge offset [unit?] = 0.201charge generation parameters (RABBIT)number of points in distributed chargemaximum extent of charge (i.e max avalanche radius?)charge integrals formulaecharge distribution (STAR)radius calculationcharge calculation
3. Charge generation14 March 20133(my)pseudo-code: “Distributed like RABBIT data”Q,r1,r2,r3=0while(r2<=r3)do r1 = uniform ]0,12000] r2 = 0.00001 * r1^(2.167) * exp(-r1*0.0008) r3 = uniform ]0,40] Q = r1 / 1100doneQuestions:what is RABBIT data?where do the parameters come from? what dimension? what do they physically represent?where does the formula (r2) come from?
4. Charge distribution (1/2)14 March 20134“Distribute charge according to STAR measurements – integrate with n_int points” (n_int = 10000)what STAR measurements? reference?why this value of n_int? how is it supposed to affect the charge distribution?avalanche radius calculationpseudo-coderadius = 1000radius_max = 3 (unit?)while(radius>radius_max)do x = 2 * radius_max * uniform ]-0.5,0.5] ( x in ]-3,3] ) y = 2 * radius_max * uniform ]-0.5,0.5] ( y in ]-3,3] ) radius = sqrt(x^2 + y^2) ( radius in ]0,sqrt(18)] )donequestionwhy this value of radius_max? it seems to have a major effects on the number of pads hit
5. Charge distribution (2/2)14 March 20135input integrals (reference?)q_integral1=6.283*pow(slope1,2)*(1.-exp(-1.*radius_max/slope1)*(1.+radius_max/slope1));q_integral2=6.283*pow(slope2,2)*(1.-exp(-1.*radius_max/slope2)*(1.+radius_max/slope2));charge calculationuses previously generated charge Q with applied charge offset (i.e. Q-Q0)codeQQQ = Q/n_int;qint1 = exp(-r1/slope1) * (1.-ratio) * (QQQ/q_integral1) * rmax;qint2 = exp(-r1/slope2) * (ratio) * (QQQ/q_integral2) * rmax;q_int = qint1 + qint2;withr1: radial extent of the charge (« radius » in my previous slide)slope1, slope2, ratio: 3 of the 6 initial parametersrmax: maximum area of avalanche (?) ==> rmax = Pi * radius_max^2reference?
6. Summary14 March 20136What is doneMokka driver for main stack (see backup for layout)small samples for e-,mu-,pi- have been producedDigitiser as Marlin processor implementedbased on RPCSim C++What I need to doimplement TailCatcher Mokka driverunderstand exactly how the digitisation workwhat parameters to play/not play withthe various physical models used as inputultimately rewrite the digitiser
7. Backup14 March 20137
8. Stack layout14 March 20138Steel SheetThick MylarThin MylarPad BoardPCBASICCopper SheetTungsten AbsorberSteel SupportThick GlassThick GlassThick GlassGas+FLThin GlassThinGlassThin Glassplastic borderplastic borderyzW-DHCAL CassetteW-AHCAL AbsorberNote: Gas volume is actually 15 gas volumes in Y-direction, interleaved with 12 fishlinesThickness [mm]Fishline1.15Steel sheet2.00Thick Mylar0.20Thick Glass1.15Gas1.15Thin Glass0.85Thin Mylar0.10Pad Board1.60PCB1.60ASIC1.90Copper sheet2.00