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TCAD Simulation of the MuPix7 Sensor for theMu3e Pixel Tracker
Annie Meneses Gonzalez
Physikalisches Institut Heidelberg
DPG Spring MeetingMarch 19, 2018
Annie Meneses Gonzalez [email protected] Physikalisches Institut Heidelberg
TCAD Simulation of the MuPix7 Sensor for the Mu3e Pixel Tracker 1 / 17
Outline
• The Mu3e Experiment∗ Goal∗ Challenges
• TCAD Simulation
∗ Motivation∗ Synopsis Sentaurus Software∗ Device Structure (MuPix7)∗ Simulation of quasi-stationary characteristics∗ Transient simulation of MIP
• Summary
Annie Meneses Gonzalez [email protected] Physikalisches Institut Heidelberg
TCAD Simulation of the MuPix7 Sensor for the Mu3e Pixel Tracker 2 / 17
The Mu3e Experiment
Decay µ→eee mediated by neutrino mixing
BR (µ+ → e+e−e+)10−54→StandardModel
• Too small to access experimentally
• An experimental observation: a clearsignature of new Physics
Search for Physics Beyond SMvia the Charged Lepton FlavorViolation decay
Annie Meneses Gonzalez [email protected] Physikalisches Institut Heidelberg
TCAD Simulation of the MuPix7 Sensor for the Mu3e Pixel Tracker 3 / 17
Challenges of the Experiment
1. High decay rate of muon• πE5 at PSI⇒ 108 Hz Phase I⇒ 290 days of data taking• 109 Hz Phase II (possibility under investigation at PSI)
Annie Meneses Gonzalez [email protected] Physikalisches Institut Heidelberg
TCAD Simulation of the MuPix7 Sensor for the Mu3e Pixel Tracker 4 / 17
Challenges of the Experiment
1. High decay rate of muon• πE5 at PSI⇒ 108 Hz Phase I⇒ 290 days of data taking• 109 Hz Phase II (possibility under investigation at PSI)
Two categories of background
Accidental Background Irreducible Background
2. Good vertex and timing resolution⇒ 100 µm and 500 ps
3. Excellent momentum resolution⇒ 0.5 MeV
Annie Meneses Gonzalez [email protected] Physikalisches Institut Heidelberg
TCAD Simulation of the MuPix7 Sensor for the Mu3e Pixel Tracker 5 / 17
High Voltage Monolithic Active Pixel Sensors
• Low momenta decay electrons⇒ up to 53 MeV• Multiple Coulomb scattering
Pixel tracker based on 50 µm thin HV-MAPS
∗ Integration of sensor andreadout functionalities⇒ Reduce material budget
Annie Meneses Gonzalez [email protected] Physikalisches Institut Heidelberg
TCAD Simulation of the MuPix7 Sensor for the Mu3e Pixel Tracker 6 / 17
Technology Computer Aided Design
• MAPS reversely biased to highvoltages
• Thick depleted area⇒ 15 µm for 20 Ωcm
• Fast time collection via drift⇒ time resolution better than 15 ns
TCADUse of computer simulations to develop and optimize semiconductorprocessing technologies and devices
Annie Meneses Gonzalez [email protected] Physikalisches Institut Heidelberg
TCAD Simulation of the MuPix7 Sensor for the Mu3e Pixel Tracker 7 / 17
Synopsys Sentaurus TCAD
Annie Meneses Gonzalez [email protected] Physikalisches Institut Heidelberg
TCAD Simulation of the MuPix7 Sensor for the Mu3e Pixel Tracker 8 / 17
MuPix7• First HV-MAPS prototype which include all the
funtionalities required for the Mu3e experiment
Pixel size [µm2] 103 x 80Bulk resistance [Ωcm] 20Active area [mm2] 10.6Thickness [µm] 50 Layout of the MuPix7 pixel unit cell
with nine charge collecting diodesand the in-pixel circuitryExperimental results:
∗ DESY-II beam test facility∗ EUDET Telescope⇒MAPS MIMOSA-26
∗ 4 GeV electron beam
https://arxiv.org/abs/1803.01581
Annie Meneses Gonzalez [email protected] Physikalisches Institut Heidelberg
TCAD Simulation of the MuPix7 Sensor for the Mu3e Pixel Tracker 9 / 17
Creation of the Structure
1. Accurate prediction of the geometry and doping distribution
Build mesh distribution
2. Simulation of quasi-stationary characteristics
Annie Meneses Gonzalez [email protected] Physikalisches Institut Heidelberg
TCAD Simulation of the MuPix7 Sensor for the Mu3e Pixel Tracker 10 / 17
Quasi-stationary characteristics
• Electric Field profile
Annie Meneses Gonzalez [email protected] Physikalisches Institut Heidelberg
TCAD Simulation of the MuPix7 Sensor for the Mu3e Pixel Tracker 11 / 17
Signal generation from Minimum Ionizing Particles
• Energy loss⇒ 5 MeV/cm
• Electron beam⇒ 4 GeV
• Ionization Energy⇒ Silicon 3.6 eV
Linear Energy Transfer
⇒ 2×10−5 pC/µm
⇒ 130 e− h/µm
Annie Meneses Gonzalez [email protected] Physikalisches Institut Heidelberg
TCAD Simulation of the MuPix7 Sensor for the Mu3e Pixel Tracker 12 / 17
Signal generation from Minimum Ionizing Particles
• Fit function
Annie Meneses Gonzalez [email protected] Physikalisches Institut Heidelberg
TCAD Simulation of the MuPix7 Sensor for the Mu3e Pixel Tracker 13 / 17
Charge collection time
Bias Voltage⇒ -40 V
• Edge of the pixel⇒ Charge sharing
• Between diodes⇒ Not fully depleted⇒ Lost by recombination⇒ Collected via diffusion
Annie Meneses Gonzalez [email protected] Physikalisches Institut Heidelberg
TCAD Simulation of the MuPix7 Sensor for the Mu3e Pixel Tracker 14 / 17
Charge collection time
Bias Voltage⇒ -40 V
• Edge of the pixel⇒ Charge sharing
• Between diodes⇒ Not fully depleted⇒ Lost by recombination⇒ Collected via diffusion
Annie Meneses Gonzalez [email protected] Physikalisches Institut Heidelberg
TCAD Simulation of the MuPix7 Sensor for the Mu3e Pixel Tracker 15 / 17
Charge collection time
Bias Voltage⇒ -85 V
Annie Meneses Gonzalez [email protected] Physikalisches Institut Heidelberg
TCAD Simulation of the MuPix7 Sensor for the Mu3e Pixel Tracker 16 / 17
Summary
• The structure and collection process of MuPix7 was reproduced.
• Taking into account the limited position resolution of themeasurement, all major features are reproduced by the simulation.
• Simulation can be used to further optimize the charge collectionprocess and timing behavior in future devices.
Annie Meneses Gonzalez [email protected] Physikalisches Institut Heidelberg
TCAD Simulation of the MuPix7 Sensor for the Mu3e Pixel Tracker 17 / 17