Pixel characterization for the ITS/MFT upgrade Audrey Francisco QGP France, Etretat, 14/10/2015
Outline 1 The MFT upgrade 2 Pixel sensor Technology choice Full scale prototypes 3 Characterization campaign Methods Experimental results A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 2 / 19
The Muon Forward Tracker Limitations of the Muon Spectrometer high level of background from π/k decays impossibility to determine muon production vertex no c/b separation (inclusive J/ψ spectra) limited mass resolution A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 3 / 19
The Muon Forward Tracker Adding vertex capabilities to the current Muon Spectrometer Closer to the interaction point Track matching spectrometer-mft High pointing resolution (< 100 µm) Installation during the next shutdown (2019) A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 4 / 19
The Muon Forward Tracker Design objectives 5 detection disks (Si) 912 pixels (0.4 m 2 ) 0.6%X 0 per disk 768 mm< z< 460 mm Technical specifications Spatial resolution 5 µm Detection efficiency > 99.5% Sensor thickness 50 µm Power dissipation < 150 m W cm 2 Radiation tolerance O(10 13 MeV n eq cm 2 ) A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 5 / 19
Pixel sensor Technology choice Monolithic Active Pixels Sensor (MAPS) architecture CMOS TowerJazz 0.18 µm sensors Detection and read-out on the same substrate Possibility of back-biasing 2012 Explorer-0 2013 May 2014 Explorer-1 palpidess-0 palpide-1 palpidess-1 investigator April 2015 Oct. 2015 Febr. 2016 palpide-2 palpide-3 ALPIDE A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 6 / 19
Pixel sensor palpide-1: 1st full scale prototype 512x1052 pixel matrix (15 mmx30 mm) Pixel size: 28 µm x 28 µm In-pixel discriminator Power consumption: 39 mw cm 2 4 sectors with different pixel layouts A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 7 / 19
Pixel sensor palpide-2 Pixel Matrix and matrix readout from palpide Support integration of module prototypes Close to final physical layout of pads and interfaces Full final Control Interface functionalities Support of OB Module local data bus A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 8 / 19
Pixel sensor Characterization methods Laboratory tests Noise and threshold measurements Radioactive source measurements Influence of specific parameters (ex: T) Pixel threshold vs Ithr param. ( palpide-1) A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 9 / 19
Pixel sensor Characterization methods Test beam Measurement of detection efficiency and spatial resolution Intensive campaign from 60 MeV to 120 GeV (PS, SPS, DESY, BTF, PAL) Example at PS in May 2015: A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 10 / 19
palpide-1 results Lab measurements: temperature effect Threshold vs temperature for 2.5 10 12 n eq cm 2 irradiated chip Slight increase of threshold for Sector 2 Stable temperature in the cavern A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 11 / 19
palpide-1 results Beam test: hitmap and performances (PS, 6 GeV π ) Hitmap: regions separated by double dead columns Efficiency > 99.5% Noise occupancy < 10 5 Detection efficiency and noise occupancy vs Ithr current A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 12 / 19
palpide-1 results Beam test: resolution and cluster size (PS, 6 GeV π ) Required resolution < 5 µm wide operating range Resolution: slight increase after irradiation A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 13 / 19
palpide-1 results Beam test: sector comparison and irradiation effect (PS, 6 GeV π ) Same sector behaviour with irradiation Sector 2 show slightly better performances than Sector 1 Acceptable operating range even for high irradiation level A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 14 / 19
palpide-2 results Lab measurements: Mean threshold and noise values as a function of ITHR Average values over 1% of the pixels of 8 different chips Vbb = 0 V A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 15 / 19
palpide-2 results Beam test: Efficiency and fake hit rate (PS, 6 GeV π ) 4 µm spacing 25 µm epi Vbb = 6 V PMOS reset A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 16 / 19
palpide-2 results Beam test: Resolution and cluster size (PS, 6 GeV π ) 4 µm spacing 25 µm epi Vbb = 6 V PMOS reset A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 17 / 19
Pixel sensor palpide-3 First prototype to allow full integration into MFT ladder Same dimensions (final layout) Testing should start very soon (expected at the beginning of November) Main features 8 sectors In-pixel multi event buffer Charge threshold: -15% High speed Serial DTU Equ. noise charge: -30% A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 18 / 19
Summary First prototypes show expected performances Outlook palpide-2 chip at Subatech Take part in the palpide-3 characterization campaign PhD at Subatech : Measurement of the J/ψ elliptic flow Thank you for your attention A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 19 / 19
BACKUP A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 19 / 19
palpide-2 sectors A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 19 / 19
Alpide front end : diode reset A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 19 / 19
Alpide front end : PMOS reset A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 19 / 19
MFT position A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 19 / 19
For Further Information... Bibliography ALICE, Letter of Intent for the Upgrade of the ALICE Experiment, CERN-LHCC-2012-012 (2012) ALICE, Addendum to the Letter of Intent for the Upgrade of the ALICE Experiment, CERN-LHCC-2013-014 (2013) ALICE, Technical Design Report for the Upgrade of the ALICE Inner Tracking System, CERN-LHCC-2013-024 (2013) ALICE, Technical Design Report for the Muon Forward Tracker, CERN-LHCC-2015-001 (2015) A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 19 / 19
For Further Information... Presentations Luciano Musa, Upgrade of the ALICE Inner Tracking System, PH Detector Seminar, 17/04/2015 Monika Kofarago, Upgrade of the Inner Tracking System of ALICE with a focus on pixel sensor development, 24th International Workshop on Vertex Detectors, 1/06/15 TWiki pages Muon Forward Tracker https: //twiki.cern.ch/twiki/bin/view/alice/muonforwardtracker ITS upgrade Work Package 5 (WP5) https://twiki.cern.ch/twiki/bin/view/alice/its-wp5 A. Francisco (Subatech) QGP France - ITS/MFT Pixels Etretat, 14/10/2015 19 / 19