The DMAPS upgrade of the Belle II vertex detector Babeluk, M.; Barbero, M.; Baudot, J. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/2024, Letnik:
1064
Journal Article
Recenzirano
The Belle II experiment at KEK in Japan considers an upgrade for the vertex detector system in line with the accelerator upgrade for higher luminosity at long shutdown 2 planned for 2028.
One ...proposal for the upgrade of the vertex detector called VTX aims to improve background robustness and reduce occupancy using small and fast pixels. VTX accommodates the OBELIX depleted monolithic active CMOS pixel sensor (DMAPS) on all five proposed layers. OBELIX is specifically developed for the VTX application and based on the TJ-Monopix2 chip initially developed to meet the requirements of the outer layers of the ATLAS inner tracker (ITk).
This paper will review recent tests of the TJ-Monopix2 chip as well as various design aspects of the OBELIX-1 chip currently under development.
The upgrade of the tracking detectors for the High Luminosity-LHC (HL-LHC) requires the development of novel radiation hard silicon sensors. The development of Depleted Monolithic Active Pixel ...Sensors targets the replacement of hybrid pixel detectors with radiation hard monolithic CMOS sensors. We designed, manufactured and tested radiation hard monolithic CMOS sensors in the TowerJazz 180 nm CMOS imaging technology with small electrodes pixel designs. These designs can achieve pixel pitches well below current hybrid pixel sensors (typically 50 × 50μm) for improved spatial resolution. Monolithic sensors in our design allow to reduce multiple scattering by thinning to a total silicon thickness of only 50μm. Furthermore monolithic CMOS sensors can substantially reduce detector costs. These well-known advantages of CMOS sensor for performance and costs can only be exploited in pp-collisions at HL-LHC if the DMAPS sensors are designed to be radiation hard, capable of high hit rates and have a fast signal response to satisfy the 25 ns bunch crossing structure of LHC. Through the development of the MALTA and Mini-MALTA sensors we show the necessary steps to achieve radiation hardness at 1015 neq/cm2 for DMAPS with small electrode designs. The sensors combine high granularity (pitch 36.4x36.4μm2), low detector capacitance (<5fF/pixel) of the charge collection electrode (3μm), low noise (ENC≈10 e−) and low power operation (1μW/pixel) with a fast signal response (25 ns bunch crossing). The sensors feature arrays of 512 × 512 (MALTA) and 16 × 64 (Mini-MALTA) pixels. To cope with high hit rates expected at HL-LHC (>200 MHz/cm2) we have implemented a novel high-speed asynchronous readout architecture. The paper summarises the optimisation of the pixel design to achieve radiation hard pixel designs with full efficiency after irradiation at >98% after 1015 neq/cm2).
Depleted Monolithic Active Pixel Sensors (DMAPS) are monolithic pixel detectors with high-resistivity substrates designed for use in high-rate and high-radiation environments. They are produced in ...commercial CMOS processes, resulting in relatively low production costs and short turnaround times, and offer a low material budget. LF-Monopix1 and TJ-Monopix1 are large DMAPS prototypes produced in 150 nm LFoundry and 180 nm TowerJazz technology, respectively, that follow two different design concepts regarding the charge collection electrode. Prototypes of both development lines have been extensively tested and characterized over the last years. The second-generation Monopix prototypes, Monopix2, were recently produced. They were designed to address the shortcomings of their predecessors, in particular related to radiation hardness and cross talk, and further improve upon their performance. The latest measurements with LF-Monopix1 and TJ-Monopix1 concerning hit efficiency, depletion, and radiation hardness as well as the initial test results of the new Monopix2 prototypes are presented.
Depleted Monolithic Active Pixel Sensors (DMAPS) constitute a promising low cost alternative for the outer layers of the ATLAS experiment Inner Tracker (ITk). Realizations in modern, high resistivity ...CMOS technologies enhance their radiation tolerance by achieving substantial depletion of the sensing volume. Two DMAPS prototypes that use the same “column-drain” readout architecture and are based on different sensor implementation concepts named LF-Monopix and TJ-Monopix have been developed for the High Luminosity upgrade of the Large Hadron Collider (HL-LHC).
LF-Monopix was fabricated in the LFoundry 150 nm technology and features pixel size of 50×250μm2 and large collection electrode opted for high radiation tolerance. Detection efficiency up to 99% has been measured after irradiation to 1⋅1015neq∕cm2. TJ-Monopix is a large scale (1×2cm2) prototype featuring pixels of 36×40μm2 size. It was fabricated in a novel TowerJazz 180 nm modified process that enables full depletion of the sensitive layer, while employing a small collection electrode that is less sensitive to crosstalk. The resulting small sensor capacitance (≤3 fF) is exploited by a compact, low power front end optimized to meet the 25 ns timing requirement. Measurement results demonstrate the sensor performance in terms of Equivalent Noise Charge (ENC) ≈11e−, threshold ≈300e−, threshold dispersion ≈30e− and total power consumption lower than 120 mW/cm2.
•Depleted monolithic pixel sensors developed for the ATLAS ITk.•Different implemenation concepts featuring large and small collection electrodes.•Process modification to combine small capacitance with enhanced radiation tolerance.•Full functionality after irradiation.•High efficiency (LF-Monopix), High analog performance (TJ-Monopix).
DMAPS Monopix developments in large and small electrode designs Bespin, C.; Barbero, M.; Barrillon, P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2020, Letnik:
978
Journal Article
Recenzirano
Odprti dostop
LF-Monopix1 and TJ-Monopix1 are depleted monolithic active pixel sensors (DMAPS) in 150nm LFoundry and 180nm TowerJazz CMOS technologies respectively. They are designed for usage in high-rate and ...high-radiation environments such as the ATLAS Inner Tracker at the High-Luminosity Large Hadron Collider (HL-LHC). Both chips are read out using a column-drain readout architecture. LF-Monopix1 follows a design with large charge collection electrode where readout electronics are placed inside. Generally, this offers a homogeneous electrical field in the sensor and short drift distances. TJ-Monopix1 employs a small charge collection electrode with readout electronics separated from the electrode and an additional n-type implant to achieve full depletion of the sensitive volume. This approach offers a low sensor capacitance and therefore low noise and is typically implemented with small pixel size. Both detectors have been characterized before and after irradiation using lab tests and particle beams.
The last couple of years have seen the development of Depleted Monolithic Active Pixel Sensors (DMAPS) fabricated with a process modification to increase the radiation tolerance. Two large scale ...prototypes, Monopix with a column drain synchronous readout, and MALTA with a novel asynchronous architecture, have been fully tested and characterized both in the laboratory and in test beams. This showed that certain aspects have to be improved such as charge collection after irradiation and the output data rate. Some improvements resulting from extensive TCAD simulations were verified on a small test chip, Mini-MALTA. A detailed cluster analysis, using data from laboratory and test beam studies, at different biases, for high and low thresholds and before and after irradiation is presented, followed by detailed simulations showing that the digital architecture for both chips is capable of dealing with data rates of around 80 MHz/cm2 similar to what it is expected in the outer layer of the ATLAS inner tracker upgrade for the HL-LHC. The data rate capability and output bandwidth are studied using realistic hits generated by the ATLAS detector simulation framework.
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