6533b860fe1ef96bd12c31e7
RESEARCH PRODUCT
MALTA: a CMOS pixel sensor with asynchronous readout for the ATLAS High-Luminosity upgrade
K. MoustakasCesar Augusto Marin TobonThanushan KugathasanHeinz PerneggerPetra RiedlerTianyang WangF. PiroLluis Simon ArgemiCarlos Solans SanchezEnrico Junior SchioppaAbhishek SharmaBojan HitiFlorian DachsTomislav SuligojWalter SnoeysLeyre Flores Sanz De AcedoI. BerdalovicIgnacio Asensi TortajadaRoberto CardellaTomasz HemperekValerio DaoP. Rymaszewskisubject
PhysicsActive pixel sensors ; CMOS integrated circuits ; position sensitive particle detectors ; radiation effects ; radiation hardening (electronics) ; semiconductor detectors ; solid state circuit designPixelPhysics::Instrumentation and Detectors010308 nuclear & particles physicsbusiness.industryDetectorHigh Luminosity Large Hadron Collider01 natural sciencesCapacitance030218 nuclear medicine & medical imagingSemiconductor detector03 medical and health sciences0302 clinical medicineCMOSNuclear electronics0103 physical sciencesbusinessRadiation hardeningComputer hardwaredescription
Radiation hard silicon sensors are required for the upgrade of the ATLAS tracking detector for the High- Luminosity Large Hadron Collider (HL-LHC) at CERN. A process modification in a standard 0.18 μm CMOS imaging technology combines small, low-capacitance electrodes (∼2 fF for the sensor) with a fully depleted active sensor volume. This results in a radiation hardness promising to meet the requirements of the ATLAS ITk outer pixel layers (1.5 × 1015 neq /cm2 ), and allows to achieve a high signal-to-noise ratio and fast signal response, as required by the HL-LHC 25 ns bunch crossing structure. The radiation hardness of the charge collection to Non-Ionizing Energy Loss (NIEL) has been previously characterised on pro- totypes for different pixel sensor cell designs. The encouraging results enabled the design of full-size monolithic CMOS sensors for the ATLAS ITk outermost pixel layer, which comprises ∼1.8 m2 of pixel sensor active area. In the MALTA sensor, we implement a fast, low-power analogue front-end together with a novel high-speed matrix readout architecture capable of meeting the challenging hit- rate requirements of up to 2 MHz/mm2 in the outer layers of the ITk pixel tracker. The front- end was optimized for the low sensor capacitance to achieve low noise (ENC < 20 e-) and low power operation (< 1 μW/pixel), with timing that meets the 25 ns requirement. The small size (∼2 μm) of the collection electrode also allows better shielding to prevent crosstalk from the full swing digital signals in the 36.4×36.4 μm2 pixel. MALTA features a 512×512 pixel matrix with a fully asynchronous readout architecture, without clock distribution over the matrix. This approach combines low digital power consumption with fast signal response and high hit-rate capability. This paper describes the implementation of this novel depleted monolithic sensor based on a low-capacitance analogue design with asynchronous readout, together with first test results from lab tests, radioactive source tests and X-ray measurements.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2018-01-01 |