USBPix Readout System using FE-I4/A Chip Status Update: ToT calibration and Finalization of Tuning Procedure Jimin Kim and Austin Piehl Department of Physics University of Washington

Table of Contents Comments from Collaborators Established Goals during last week ToT Scan and Calibration Finalized General Tuning Procedure What’s next? Questions

Comments from Collaborators Bill Quayle at LBL The result does look way better, but just to point out that changing the value of Vthin_Alt_Coarse from 0 to 1 is very rarely done Lea Caminada at LBL N/A David Leon at CERN

Established Goals Last Week Finalization of general tuning process ToT Scan/Calibration Reporting the suspected bug from the software Successful installation of 4.4.1.0

ToT Scan and Calibration Charge Measurement Pixel Detector measures the charge corresponding to the energy lost by a particle traversing a silicon sensor The charge measurement is used to differentiate hits from the noise and also, to improve the spatial resolution of multi-pixel cluster The charge is collected and amplified by the charge sensitive preamplifier at FE-Chip Charge that is above the predefined threshold value is only recognized The deposited charge is measured using the recorded Time over Threshold (ToT): the period of time during which the preamplifier output signal is above a predefined threshold ToT increases proportionally with the deposited charge and is digitized in clock cycles of the module controller chip These digitized ToT signal is then converted to a charge value offline using functions obtained from fit calibration data

ToT Scan and Calibration ToT Calibration To obtain a uniform and best performance for charge measurement, ToT has to be tuned to the right value which encompasses the charge of MIP ~ particles that are way more energetic than MIP The right value of ToT should also provide a sufficient resolution FE-I4 has 2 parameters that are used in tuning ToT and it is based on 4-bit language PrmpVbpf parameter is used for global ToT adjustment FDAC: Global and local feedback adjustment, is used for pixel by pixel ToT adjustment

ToT Scan (Before IF_TUNE)

ToT Scan (After IF_TUNE, Target ToT = 6)

ToT Scan (After FDAC_TUNE, Target ToT =6)

Finalized Tuning Procedure for FE-I4/A Global Tuning DIGITAL_TEST Strobe signal is fed repeatedly straight to the discriminator Checks digital functionality/data communication Also masks dead and weird pixels ANALOG_TEST Strobe signal larger than threshold is fed repeatedly into the Analog Cell Checks Analog functionality/data communication THRESHOLD_SCAN VCAL/PulsarDAC injects various charges repeatedly into the analog pixel cell Produces the histogram of mean threshold and dispersion/S-Curve of each pixel TOT_CALIB_VERIF Defined reference charge is injected repeatedly Produces the histogram of mean ToT and dispersion GDAC_TUNE Calibrate the global threshold value (Vthin_Alt_Fine and Vthin_Alt_Coarse) and scans threshold for each step Gives the optimal value for Vthin_Alt_Fine and possibly, Vthin_Alt_Coarse IF_TUNE Calibrate global ToT value (PrmpVbpf) and scans ToT for each step Gives the optimal value for Prmpvbpf for global ToT adjustment Repeat from GDAC_TUNE until there is no change in dispersion and mean Usually repeated more than once

Finalized Tuning Procedure for FE-I4/A Pixel Tuning FDAC_TUNE Calibrate the FDAC value of each pixel to be tuned to the desired ToT value Create an FDAC map to be loaded in cfg file for pixel by pixel ToT adjustment TDAC_FAST_TUNE Roughly calibrate the TDAC value of each pixel to be tuned to the desired threshold value before the Fine tuning Create an TDAC map to be loaded in cfg file for pixel by pixel threshold adjustment TDAC_FINE_TUNE Finely calibrate the TDAC value of each pixel to be tuned to the desired threshold value along with threshold measurement Repeat from FDAC_TUNE until there is no change is mean and dispersion Usually repeated more than once THRESHOLD_SCAN To check the final tuning result for threshold calibration ToT_CALIB_VERIF To check the final tuning result for ToT calibraion NOISE_SCAN Runs at 10Khz trigger rate Identifies pixels with too high noise occupancy and create mask for those pixels

Final Tuning Result Threshold Tuning (Target Threshold = 3100e)

Final Tuning Result ToT Tuning (Target ToT = 6)

Short update on Software version 4.4.1.0 David Lean’s solutions Make sure Multi IO board is recognized after uninstalling the old driver You cannot install the new driver by right clicking on the INF file and select install The INF file is NOT executable file, therefore has to be installed manually

What’s Next? Noise Scan and Crosstalk Scan? Disabling the column 78~80? Successful installation of 4.4.1.0 by manual installation Reproduction of entire tuning process from the scratch Update TeV page once solid reproduction is successful

Questions for future Q/A