CMOS pixel sensors & PLUME operation principles J. Baudot for the IPHC-PICSEL group baudot@in2p3.fr IN2P3-KEK Belle II and BEAST meeting Strasbourg, 19-20 January 2015 CMOS pixel sensors Counting rate Radiation tolerance PLUME ladder

CMOS pixel sensors @ IPHC Motivations ILC vertex detector no trigger ➙ continuous integration performance driven high granularity low material budget The “dimensional curse” Granularity against read-out speed data throughput Potential solution get out only the relevant information In space & time Power dissipation against Material budget also shared by Heavy Ion Colliders Single point res. Integra. time TID Fluence neq/cm2 Temp. STAR - PXL ~ 5 µm ≲ 200 µs 150 kRad 3.1012 30 ∘C ALICE – ITS (in÷out) ~ 5÷10 µm 10-30 µs 700÷15 kRad 1.1013 CBM - MVD ≲ 10 MRad 1.1014 ≪0 ∘C ILD - VXD ≲ 3 µm ≲ 10 µs O(100 kRad) O(1011) ≲ 30 ∘C J.Baudot - CPS and PLUME operation principles - IN2P3-KEK BEAST meeting 19-20 January 2015

MIMOSAs architecture Rolling-shutter = power reduction One row powered at a time Parallel column read-out ➙ speed In-pixel double sampling ➙ column-level discrimination Continuously sensitive Read-out time = integration time 0-suppression = data compression Encode “fired pattern” address 1D: SUZE-01/03 2D: SUZE-02 Winning strategy if size of fired addresses < # pixels % level occupancy required Synchronous read-out Potential accelerations More rows read simultaneously Enlarged row height In-pixel discrimination ➡ AROM architecture J.Baudot - CPS and PLUME operation principles - IN2P3-KEK BEAST meeting 19-20 January 2015

CPS proposed for BEAST-II MIMOSA-26 (2008) AMS 0.35 µm Sensitive layer: 15 µm thick resistivity > 0.4 kΩ.cm Power dissipation 350 mW/cm2 Spatial resolution ~ 3 µm MISTRAL (expected Q4-2015) TowerJazz 0.18 µm Sensitive layer: 30 µm thick resistivity 1÷5 kΩ.cm Power dissipation ~ 100 mW/cm2 Spatial resolution < 10 µm MISTRAL 832x208 ~ 0.2 Mpixels Pitch 36x62.5 µm2 ➞ Sensitive area 13.0x30.0 mm2 ➞ Readout time 20 µs PRELIMINARY J.Baudot - CPS and PLUME operation principles - IN2P3-KEK BEAST meeting 19-20 January 2015

Counting rate in MIMOSAs MIMOSA features reminder: CDS in pixel / binary signal / synchronous rolling-shutter + 0-suppression + output Pixel limitation? One MIP per integration time per pixel MIMOSA-26: 10 MHz/cm2 Read-out limitations Various information bottlenecks Line max # patterns Memory size Output data throughput Information size ➙ # hits? Depends on hit local density Depends on pixel multiplicity Assumptions (for designed goals with occupancy ≪ 1%) MIMOSA-26: ~200 hits/frame ➙ ~106 hits/cm2/s MISTRAL: ~100(?) hits/frame ➙ ~(?).106 hits/cm2/s (designed for tracker outer layers) J.Baudot - CPS and PLUME operation principles - IN2P3-KEK BEAST meeting 19-20 January 2015

Pixel multiplicity in clusters WARNING: our CPS are not fully depleted Thermal motion rather than electric field drift density of collection node ➚ (smaller pitch) ➡ cluster size➘ Measured with low resistivity sensitive layer (14 µm thick): 10 µm pitch ⬄ <pixel mult.>~2.9 against 40 µm pitch ⬄ <pixel mult.>~3.4 Collection node size ➚ ➡ cluster size➘ Sensitive layer thickness ➚ ➡ cluster size➚ Sensitive layer resistivity ➚ ➡ cluster size➘ Very thin sensitive layer (15-30 µm) Impact of incident angle mitigated Example: MIMOSA-26, high resistivity 15 µm sens. layer tan(60∘)/tan(36∘)=2.4 5.7/3.3 = 1.7 J.Baudot - CPS and PLUME operation principles - IN2P3-KEK BEAST meeting 19-20 January 2015

Ionizing radiation tolerance Mechanism on collection diode Charges (from ionization) accumulated in oxide ➡ leakage current➚➡ noise ➚ Treatment µ-circuits non-affected Driving parameters S/N problem Noise cannot be helped For fixed integration time For fixed temperature Enlarge Signal as much as poss. Collecting node size Pixel size Sensitive layer thickness & resistivity Tcoolant=20∘C Observations AMS 0.35 µm Validated to 300 kRad (STAR requirement) Not much known beyond BUT “good behaviour” @ 1 Mrad for CPS in technology 0.35 µm XFAB TowerJazz 0.18 µm 3 Mrad OK for S/N (on analogue output sensor) D.Doering, U.Frankfurt J.Baudot - CPS and PLUME operation principles - IN2P3-KEK BEAST meeting 19-20 January 2015

MISTRAL integration time Nominal mode 208 rows Row read-out time 160 to 200 ns Integration time = 16.6 to 20.8 µs 0-suppression logic treats 208 rows synchronously with integration time Output memory (100 hits) read once after 208 rows treated Specific BEAST-2 mode Select 208/8 = 26 rows (1.6 mm) partial rolling-shutter Row read-out time unchanged (2 at a time) Effective integration time = 2.1-2.6 µs without dead-time 0-suppression logic sees 8 times the same 26 rows Output memory delivers 8 times the 8 rows content after 208 rows 100 hits/208(=8x26) rows ➙ ~108 hits/s/cm2 J.Baudot - CPS and PLUME operation principles - IN2P3-KEK BEAST meeting 19-20 January 2015

CPS proposed for BEAST-II MIMOSA-26 (2008) AMS 0.35 µm Sensitive layer: 15 µm thick resistivity > 0.4 kΩ.cm Power dissipation 350 mW/cm2 Spatial resolution ~ 3 µm Validated for TID~3kGy will operate beyond that point with unknown degradation MISTRAL (expected Q4-2015) TowerJazz 0.18 µm Sensitive layer: 30 µm thick resistivity 1÷5 kΩ.cm Power dissipation ~ 100 mW/cm2 Spatial resolution < 10 µm Technology validated for TID~3MRad MISTRAL 832x208 ~ 0.2 Mpixels Pitch 36x62.5 µm2 ➞ Sensitive area 13.0x30.0 mm2 ➞ Readout time 20 µs (2µs for 26 rows) PRELIMINARY J.Baudot - CPS and PLUME operation principles - IN2P3-KEK BEAST meeting 19-20 January 2015

PLUME Concept Production Beam test @ SPS (2011) Double-sided layer of pixelated sensors Designed driven by ILC-VXD Air cooled Collab: Bristol, DESY, IPHC Production PLUME-1: MIMOSA-26 sensors Material budget 0.6% X0 2 functional ladders PLUME-2 (BEAST-2 proposition baseline) Material budget 0.35% X0 ≲10 ladders in production PLUME-3 (dedicated to BEAST-2) MISTRAL sensors Material budget guess ≲ 0.5 % X0 Few ladders goal Beam test @ SPS (2011) Incident angle resolution: 0.2 degrees at 40 degrees J.Baudot - CPS and PLUME operation principles - IN2P3-KEK BEAST meeting 19-20 January 2015

Conclusion Summary Outlook Current (or nearly) available sensors have designed parameters driven by other experiments Assets Granularity Continuous integration Low material budget Thorough testing Outlook Designing a BEAST- phase – II specific sensor not out of the question Potential optimization Integration time (few µs over large surface) Occupancy (few %) BUT 20 ns time-stamping or gating mode unreachable (for next year) Readiness by Q1-2017 at the earliest J.Baudot - CPS and PLUME operation principles - IN2P3-KEK BEAST meeting 19-20 January 2015

Backups J.Baudot - CPS and PLUME operation principles - IN2P3-KEK BEAST meeting 19-20 January 2015

In-pixel double sampling