The ALICE experiment will undergo a major upgrade during the next LHC Long Shutdown scheduled in 2019–20 that will enable a detailed study of the properties of the QGP, exploiting the increased Pb-Pb ...luminosity expected during Run 3 and Run 4.
The replacement of the existing Inner Tracking System with a completely new ultra-light, high-resolution detector is one of the cornerstones within this upgrade program. The main motivation of the ITS upgrade is to provide ALICE with an improved tracking capability and impact parameter resolution at very low transverse momentum, as well as to enable a substantial increase of the readout rate.
The new ITS will consist of seven layers of innovative Monolithic Active Pixel Sensors with the innermost layer sitting at only 23 mm from the interaction point. This talk will focus on the design and the physics performance of the new ITS, as well as the technology choices adopted. The status of the project and the results from the prototypes characterization will also be presented.
The ALICE High Momentum Particle Identification RICH detector (HMPID) was installed, with its 10
m
2 of Cesium Iodide (CsI) photo-cathodes, in the ALICE experiment at the Large Hadron Collider (LHC) ...in 2006. Since then, it has been thoroughly commissioned, together with its auxiliary systems, with cosmic rays and particles from beam dump/splash events recorded during various LHC injection tests in 2008 and 2009. Finally, the HMPID has successfully detected particles produced by the first proton–proton collisions at LHC in winter 2009. The present paper reviews the experience gained during the commissioning phase and summarizes the present status of the detector. Preliminary results concerning the detector performance are also reported.
The study of open charm meson production provides an efficient tool for the investigation of the properties of hot and dense matter formed in nucleus–nucleus collisions. The interpretation of the ...existing di-muon data from the CERN SPS suffers from a lack of knowledge on the mechanism and properties of the open charm particle production. Due to this, the heavy-ion programme of the NA61/SHINE experiment at the CERN SPS has been extended by precise measurements of charm hadrons with short lifetimes. A new Vertex Detector for measurements of the rare processes of open charm production in nucleus–nucleus collisions was designed to meet the challenges of track registration and high resolution in primary and secondary vertex reconstruction. A small-acceptance version of the vertex detector was installed in 2016 and tested with Pb + Pb collisions at 150
A
GeV
/
c
. It was also operating during the physics data taking on Xe + La and Pb + Pb collisions at 150
A
GeV
/
c
conducted in 2017 and 2018. This paper presents the detector design and construction, data calibration, event reconstruction, and analysis procedure.
Active Pixel Sensors used in High Energy Particle Physics require low power consumption to reduce the detector material budget, low integration time to reduce the possibilities of pile-up and fast ...readout to improve the detector data capability. To satisfy these requirements, a novel Address-Encoder and Reset-Decoder (AERD) asynchronous circuit for a fast readout of a pixel matrix has been developed. The AERD data-driven readout architecture operates the address encoding and reset decoding based on an arbitration tree, and allows us to readout only the hit pixels. Compared to the traditional readout structure of the rolling shutter scheme in Monolithic Active Pixel Sensors (MAPS), AERD can achieve a low readout time and a low power consumption especially for low hit occupancies. The readout is controlled at the chip periphery with a signal synchronous with the clock, allows a good digital and analogue signal separation in the matrix and a reduction of the power consumption. The AERD circuit has been implemented in the TowerJazz 180nm CMOS Imaging Sensor (CIS) process with full complementary CMOS logic in the pixel. It works at 10MHz with a matrix height of 15mm. The energy consumed to read out one pixel is around 72pJ. A scheme to boost the readout speed to 40MHz is also discussed. The sensor chip equipped with AERD has been produced and characterised. Test results including electrical beam measurement are presented.
We describe the most recent efforts made by various groups in implementing resistive electrodes in micropattern gaseous detectors with the aim to combine in the same design the best features of ...Resistive Plate Chambers (RPCs)—for example, their robustness and spark-protection property—with the high granularity and thus the good position resolution offered by microelectronic technology. In the stream of this activity, we have recently developed two novel detectors with resistive electrodes; one based on resistive micromeshes and the second one is a microstrip gas chamber with resistive electrodes. We have demonstrated that the resistive meshes are a convenient construction element for various designs of spark-protective detectors, for example of parallel-plate or micropattern types. These new detectors enable considerable enhancement of the RPC and micropattern detectors applications since they feature not only high position resolution but also relatively good energy resolution (25–30% full width at half maximum and at 6
keV) and, if necessary, they can operate in the cascaded mode, allowing the achievement of a high overall gas gain.
A novel source–drain follower for monolithic active pixel sensors Gao, C.; Aglieri, G.; Hillemanns, H. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2016, Volume:
831
Journal Article
Peer reviewed
Monolithic active pixel sensors (MAPS) receive interest in tracking applications in high energy physics as they integrate sensor and readout electronics in one silicon die with potential for lower ...material budget and cost, and better performance. Source followers (SFs) are widely used for MAPS readout: they increase charge conversion gain 1/Ceff or decrease the effective sensing node capacitance Ceff because the follower action compensates part of the input capacitance. Charge conversion gain is critical for analog power consumption and therefore for material budget in tracking applications, and also has direct system impact. This paper presents a novel source–drain follower (SDF), where both source and drain follow the gate potential improving charge conversion gain. For the inner tracking system (ITS) upgrade of the ALICE experiment at CERN, low material budget is a primary requirement. The SDF circuit was studied as part of the effort to optimize the effective capacitance of the sensing node. The collection electrode, input transistor and routing metal all contribute to Ceff. Reverse sensor bias reduces the collection electrode capacitance. The novel SDF circuit eliminates the contribution of the input transistor to Ceff, reduces the routing contribution if additional shielding is introduced, provides a way to estimate the capacitance of the sensor itself, and has a voltage gain closer to unity than the standard SF. The SDF circuit has a somewhat larger area with a somewhat smaller bandwidth, but this is acceptable in most cases.
A test chip, manufactured in a 180nm CMOS image sensor process, implements small prototype pixel matrices in different flavors to compare the standard SF to the novel SF and to the novel SF with additional shielding. The effective sensing node capacitance was measured using a 55Fe source. Increasing reverse substrate bias from −1V to −6V reduces Ceff by 38% and the equivalent noise charge (ENC) by 22% for the standard SF. The SDF provides a further 9% improvement for Ceff and 25% for ENC. The SDF circuit with additional shielding provides 18% improvement for Ceff, and combined with −6V reverse bias yields almost a factor 2.
•A source–drain follower (SDF) for monolithic active pixel sensors is proposed.•The SDF reduces the input capacitance increasing the charge conversion gain.•The SDF can provide improved noise-power performance.•The SDF with shielding provides further improvement.•The SDF with shielding provides a way to measure the sensor capacitance.
We have developed a cost-effective technology for manufacturing various layouts of micropattern gaseous detectors for a wide range of applications. Such devices feature resistive electrodes ...interfaced to a network of thin readout strips/electrodes. The following three examples of such innovative designs and their applications will be presented: a prototype of a novel double-phase liquid argon detector with a CsI photocathode immersed inside the liquid argon, a CsI-RICH detector prototype for the ALICE upgrade and GEM-like sensors for environmental safety/security applications.
•Micropattern gaseous detectors.•Dual phace noble liquid TPC.•Resistive microhole-microdot detector.•CsI photocathode.•Resistive microstrip detector.•Rn detector.•Flame detector.
Within the R&D activities for the upgrade of the ALICE Inner Tracking System (ITS), Monolithic Active Pixel Sensors (MAPS) are being developed and studied, due to their lower material budget (~0.3%X0 ...in total for each inner layer) and higher granularity (~20μm×20μm pixels) with respect to the present pixel detector. This paper presents the design and characterization results of the Explorer0 chip, manufactured in the TowerJazz 180nm CMOS Imaging Sensor process, based on a wafer with high-resistivity (ρ>1kΩcm) and 18μm thick epitaxial layer. The chip is organized in two sub-matrices with different pixel pitches (20μm and 30μm), each of them containing several pixel designs. The collection electrode size and shape, as well as the distance between the electrode and the surrounding electronics, are varied; the chip also offers the possibility to decouple the charge integration time from the readout time, and to change the sensor bias. The charge collection properties of the different pixel variants implemented in Explorer0 have been studied using a 55Fe X-ray source and 1–5GeV/c electrons and positrons. The sensor capacitance has been estimated, and the effect of the sensor bias has also been examined in detail. A second version of the Explorer0 chip (called Explorer1) has been submitted for production in March 2013, together with a novel circuit with in-pixel discrimination and a sparsified readout. Results from these submissions are also presented.
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