Characterization of a Pixel Sensor for ITK In the ATLAS Pixel Group at CERN May 5, 2017 Alina Arranhado

INTRODUCTION May 5, 2017 Alina Arranhado

INTRODUCTION ATLAS is one of the 4 big experiments of the LHC Phase-II upgrade aims for an increase in luminosity ATLAS May 5, 2017 Alina Arranhado

INTRODUCTION ATLAS is one of the 4 big experiments of the LHC Phase-II upgrade aims for an increase in luminosity Evaluating different technology options for the ATLAS Pixel ITK Aim: Increase radiation tolerance, less power consumption, more granularity ATLAS Inner Tracker Pixel Sensor May 5, 2017 Alina Arranhado

SILICON DETECTOR How does a silicon detector work? May 5, 2017 Alina Arranhado

SILICON DETECTOR How does a silicon detector work? CMOS technology Separate circuit for each pixel Semiconductor material, current flows in one direction only ( diode) Potential in opposite direction Ionization  Electron-hole-pairs => electrical signal May 5, 2017 Alina Arranhado

Tower-jazzTJ 180 investigator chip LASER SETUP Laser induced transient current technique Device under test: Tower-jazzTJ 180 investigator chip Power supply / control, data monitoring May 5, 2017 Alina Arranhado

SETUP Voltage divider May 5, 2017 Alina Arranhado

MEASUREMENTS May 5, 2017 Alina Arranhado

MEASUREMENTS May 5, 2017 Alina Arranhado

MEASUREMENTS Desired result: clearly defined area of high potential drop at the pixel sensor → localize the pixel sensor's position relative to the laser → detailed investigation of area of interest Problem: defocused laser beam → refocus and measure beam width May 5, 2017 Alina Arranhado

BEAM WIDTH Aim: measuring minimum laser beam width  varying distance between laser and diode Laser Diode (~5mm) Beam shape May 5, 2017 Alina Arranhado

RESULTS Response changes like S-shape  calculate beam width Sensor Response (mV) Sensor Response (mV) 𝑃 𝑋 = 𝑃𝑇𝑂𝑇 2 1− erf 2 𝑋−𝑋0 𝜔𝑥 Response changes like S-shape  calculate beam width May 5, 2017 Alina Arranhado

OTHER CONTRIBUTIONS Calibration of the temperature read-out system (Voltron) Aim: thermal characterization of ITK Stave prototypes Voltron ID to distinguish several Voltrons Arduino May 5, 2017 Alina Arranhado

VOLTRON – CALIBRATION Use 3 reference resistors calculate calibration constant Plot the expected resistance vs the measured resistance  results are very linear May 5, 2017 Alina Arranhado

CONCLUSIONS Measuring beam spot shape (width) Calibration of Voltron Understanding underlying physics Conducting several measurements Outlook: measure a signal from the Tower-jazz chip analyse data of three contiguous pixels May 5, 2017 Alina Arranhado

Meeting very interesting people CONCLUSIONS Measuring beam spot shape (width) Calibration of Voltron Meeting very interesting people Understanding underlying physics Conducting several measurements Outlook: measure a signal from the Tower-jazz chip analyse data of three contiguous pixels May 5, 2017 Alina Arranhado

CONCLUSIONS It was a very positive experience! Measuring beam spot shape (width) Calibration of Voltron Meeting very interesting people Understanding underlying physics Conducting several measurements Outlook: measure a signal from the Tower-jazz chip analyse data of three contiguous pixels It was a very positive experience! May 5, 2017 Alina Arranhado

THANK YOU! May 5, 2017 Alina Arranhado