Strobe delay scans in STcontrol Jrn Grosse-Knetter Intro: strobe - PowerPoint PPT Presentation

Strobe delay scans in STcontrol Jörn Grosse-Knetter

Intro: strobe delay scans (1)  See talk from Joseph Hu last week − Timing and time walk behaviour of FE  A lot of code from ROD was there, but based on MCC (similar to TurboDAQ scans): − T0_SCAN:  loop 0 scans strobe delay, loop 1 scans trigger delay, only one LVL1 is used, PlsrDAC=1000 (fixed)  End-of-loop-0 action: fit strobe delay → time threshold  End-of-loop-1 action: − Find trigger delay with most working pixels → store for later use − Neighbouring trg. delay: use for strobe delay calibration → stored in FE config − Shift strobe delay for best trg. delay by 5ns → store for later use 27 June 2011 strobe delay scans 2

Intro: strobe delay scans (2)  Existing code cont'd: − TIMEWALK_SCAN:  Run with trigger delay from T0 scan, read only one LVL1  loop 0 scans strobe delay, loop 1 scans PlsrDAC  End-of-loop-0 action: fit strobe delay → time threshold  End-of-loop-1 action: none (to be time walk analysis?) − INTIME_THRESH_SCAN:  Run with trigger delay and strobe delay from T0 scan, read only one LVL1  Otherwise normal threshold scan with S-curve fit − Re-activated all 3 scans and adapted to FE-I4 27 June 2011 strobe delay scans 3

Strobe delay scan & fit (1)  Scan occupancy vs pulser delay DAC  Online S-curve fitting (almost) fine: − Ignoring points below 100% eff. after plateau − Needed adaption of code to not use PlsrDAC calibration → new end-of-loop action DELAY_FIT  Result in TIMEWALK histo.: calibrated to ns 27 June 2011 strobe delay scans 4

Strobe delay scan & fit (2)  Only available offline (ModuleAnalysis) since slow: − Box fit with Minuit adjust to your − Recommended scan results / settings, seems to fit settings reliably − Added new FIT_PAR0...5 histograms for general fit output − Fit status displayed and abort possible 27 June 2011 strobe delay scans 5

Strobe delay scan & fit (3)  Box-fit parameters (in delay DAC's not ns!): − Centre = central pos. − Width = lower 50% to upper 50% point − Sigmas: erf.-smearing 25.6 ns Width of box fit 27 June 2011 strobe delay scans 6

DELAY_FIT vs box fit Box fit t centre in delay-DAC units DELAY_FIT: t rise in ns Mean = 28.1ns Mean: t rise = 15.37 ns → t rise =28.1ns-25.6/2ns=15.3 ns ✓ 27 June 2011 strobe delay scans 7

Result T0 scan Trigger delay = 56 Trigger delay = 57 Default: 1 of 6 mask steps 27 June 2011 strobe delay scans 8

T0 scan end-of-loop action  After complete T0_SCAN: new end-of-loop action T0_SET:  Set trigger delay in group  Set PlsrDelay and delay calib. (in ns/DAC-step) 27 June 2011 strobe delay scans 9

Timewalk scan  Can plot (calibrated) strobe delay vs PlsrDAC  Fit doesn't seem to work for every scan point → check  Check PlsrDAC problems at single pixel high charge ( → ToT mode?)  So far no analysis module avg. single pixel 27 June 2011 strobe delay scans 10

In-time threshold in-time threshold (e) overdrive (e) (tuned to 3000e discr. threshold) (in-time-thresh. – discrim. thresh.) 27 June 2011 strobe delay scans 11

Summary  Adapted all strobe delay scans from MCC to FE-I4, re-activated all timing scans  Added more fitting functionality in MA  All seem to work reasonably well, but: − Problems in reliability of online fitting, may have to be looked at − Need analysis for time walk scan  Code for TurboDAQ data exists in MA, adapt?  Code is in svn (not in release 1.3, trunk only) 27 June 2011 strobe delay scans 12