Lessons learned in the IBL project Miucci, A.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/2016, Volume:
824
Journal Article
Peer reviewed
Open access
The ATLAS experiment is ready for Run II of the LHC with improved tracking performance thanks to the installation of a new Pixel Detector layer, called the Insertable B-Layer (IBL). The IBL was ...installed in May 2014 located at only 3.3cm radius from the beam axis and has been successfully taking data since the beginning of Run II in June 2015. An overview of the lessons learned during the IBL construction will be presented, focusing on the challenges and highlighting the issues met during the production, integration, installation and commissioning phases of the detector.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The ATLAS experiment will upgrade its pixel detector with the installation of a new pixel layer in 2013-14. The new sub-detector, named Insertable B-layer (IBL), will be installed between the ...existing pixel detector and a new smaller radius beam-pipe at a radius of 3.3 cm. To cope with the high radiation and pixel occupancy due to the proximity to the interaction point, a new read-out chip and two different silicon sensor technologies (planar and 3D) have been developed. Furthermore, the physics performance should be improved through the reduction of pixel size while a low material budget should be imposed. A new mechanical support using lightweight staves and a CO sub(2) based cooling system is used. An overview of the IBL project and the status of the production of staves and the qualification of the assembly procedure, the loaded module electrical integrity and the read-out chain will be presented.
Abstract
The development of instrumentation for operation in
high-radiation environments represents a challenge in various
research fields, particularly in particle physics experiments and
space ...missions, and drives an ever-increasing demand for irradiation
facilities dedicated to radiation hardness studies. Depending on the
application, different needs arise in terms of particle type, energy
and dose rate. In this article, we present a versatile installation
based on a medical cyclotron located at the Bern University Hospital
(Inselspital), which is used as a controlled 18-MeV proton
source. This accelerator is used for daily production of medical
radioisotopes, as well as for multidisciplinary research, thanks to
a 6.5-meter long beam transfer line that terminates in an
independent bunker, dedicated only to scientific activities. The
facility offers a wide range of proton fluxes, due to an adjustable
beam current from approximately 10 pA to the micro-ampere range,
together with a series of steering and focusing magnets along the
beamline that allow for the beam spot to be focused down to a few
mm^2. The beamline can be instrumented with a variety of beam
monitoring detectors, collimators, and beam current measurement
devices to precisely control the irradiation conditions. The
facility also hosts a well equipped laboratory dedicated to the
characterisation of samples after irradiation. An experimental
validation of the irradiation setup, with proton fluxes ranging from
5×10^9 cm^-2s^-1 to
4×10^11 cm^-2s^-1, is reported.
The TT-PET collaboration is developing a small animal TOF-PET scanner based on monolithic silicon pixel sensors in SiGe BiCMOS technology. The demonstrator chip, a small-scale version of the final ...detector ASIC, consists of a 03×1 pixel matrix integrated with the front-end, a 50 ps binning TDC and read out logic. The chip, thinned down to 100 μm and backside metallized, was operated at a voltage of 180 V. The tests on a beam line of minimum ionizing particles show a detection efficiency greater than 99.9% and a time resolution down to 110 ps.
The TT-PET collaboration is developing a PET scanner for small animals with 30ps time-of-flight resolution and sub-millimetre 3D detection granularity. The sensitive element of the scanner is a ...monolithic silicon pixel detector based on state-of-the-art SiGe BiCMOS technology. The first ASIC prototype for the TT-PET was produced and tested in the laboratory and with minimum ionizing particles. The electronics exhibit an equivalent noise charge below 600e−RMS and a pulse rise time of less than 2ns, in accordance with the simulations. The pixels with a capacitance of 0.8pF were measured to have a detection efficiency greater than 99% and, although in the absence of the post-processing, a time resolution of approximately 200ps.
Monolithic active pixel sensors (MAPS) based on commercial high-voltage CMOS processes are an exciting technology that is considered as an option for the ATLAS Inner Tracker upgrade. Particles are ...detected using deep n-wells on a p-type substrate as sensor diodes with the depleted region extending into the silicon bulk. With readout electronics and sensor integrated on the same device, the detector complexity and the material budget are greatly reduced. The ATLASPix1 pixel sensor prototype is a large-scale MAPS prototype that implements the full readout chain on a single physical chip. It features a large in-pixel sensor electrode and is produced using the ams aH18 high voltage technology. Three pixel matrices with different readout architectures, triggered and untriggered, and pixel designs are implemented. We show the performance of one of the pixel matrix variants for samples irradiated up to 1015 1MeV meq/cm2.
HV-CMOS pixel sensors are a promising option for the tracker upgrade of the ATLAS experiment at the LHC, as well as for other future tracking applications in which large areas are to be instrumented ...with radiation-tolerant silicon pixel sensors. We present results of testbeam characterisations of the 4th generation of Capacitively Coupled Pixel Detectors (CCPDv4) produced with the ams H18 HV-CMOS process that have been irradiated with different particles (reactor neutrons and 18 MeV protons) to fluences between 1×1014 and 5×10151−MeV−neq. The sensors were glued to ATLAS FE-I4 pixel readout chips and measured at the CERN SPS H8 beamline using the FE-I4 beam telescope. Results for all fluences are very encouraging with all hit efficiencies being better than 97% for bias voltages of 85V. The sample irradiated to a fluence of 1×1015neq—a relevant value for a large volume of the upgraded tracker—exhibited 99.7% average hit efficiency. The results give strong evidence for the radiation tolerance of HV-CMOS sensors and their suitability as sensors for the experimental HL-LHC upgrades and future large-area silicon-based tracking detectors in high-radiation environments.
In view of the tracking detector application to the ATLAS High Luminosity LHC (HL-LHC) upgrade, we have developed a new generation of High Voltage CMOS (HV-CMOS) monolithic pixel-sensor prototypes ...featuring the AMS aH18 (180 nm) commercial CMOS technology. By fully integrating both analog and digital readout-circuitry on the same particle-detecting substrate, current challenges of hybrid sensor technologies, i.e., larger readout input-capacitance, lower production-yield, and higher production and integration cost, can be downscaled. The large electrode design using high-resistivity substrates actively helps to mitigate the charge-trapping effects, making these chips radiation hard. The surface and bulk damage induced in high irradiation environment change the effective doping concentration of the device, which modulates high electric fields as the reverse-bias voltage increases. This effect can cause high leakage current and premature electrical breakdown, driven by impact ionization. In order to assess the characteristics of heavily irradiated samples, we have carried out dedicated campaigns on ATLASPix1 chips that included irradiations of neutrons and protons, made at different facilities. Here, we report on the electrical characterization of the irradiated samples at different ambient conditions, also in comparison to their pre-irradiation properties. Results demonstrate that hadron irradiated devices can be safely operated at a voltage high enough to allow for high efficiency, up to the fluence of 2×1015 neq/cm2, beyond the radiation levels (TID and NIEL) expected in the outermost pixel layers of the new ATLAS tracker for HL-LHC.
High-voltage pixel sensors for ATLAS upgrade Perić, I.; Kreidl, C.; Fischer, P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2014, Volume:
765
Journal Article
Peer reviewed
Open access
The high-voltage (HV-) CMOS pixel sensors offer several good properties: a fast charge collection by drift, the possibility to implement relatively complex CMOS in-pixel electronics and the ...compatibility with commercial processes. The sensor element is a deep n-well diode in a p-type substrate. The n-well contains CMOS pixel electronics. The main charge collection mechanism is drift in a shallow, high field region, which leads to a fast charge collection and a high radiation tolerance. We are currently evaluating the use of the high-voltage detectors implemented in 180nm HV-CMOS technology for the high-luminosity ATLAS upgrade. Our approach is replacing the existing pixel and strip sensors with the CMOS sensors while keeping the presently used readout ASICs. By intelligence we mean the ability of the sensor to recognize a particle hit and generate the address information. In this way we could benefit from the advantages of the HV sensor technology such as lower cost, lower mass, lower operating voltage, smaller pitch, smaller clusters at high incidence angles. Additionally we expect to achieve a radiation hardness necessary for ATLAS upgrade. In order to test the concept, we have designed two HV-CMOS prototypes that can be readout in two ways: using pixel and strip readout chips. In the case of the pixel readout, the connection between HV-CMOS sensor and the readout ASIC can be established capacitively.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The TT-PET project aims at developing a compact Time-of-flight PET scanner with 30ps time resolution, capable of withstanding high magnetic fields and allowing for integration in a traditional MRI ...scanner, providing complimentary real-time PET images. The very high timing resolution of the TT-PET scanner is achieved thanks to a new generation of Silicon-Germanium (Si-Ge) amplifiers, which are embedded in monolithic pixel sensors. The scanner is composed of 16 detection towers as well as cooling blocks, arranged in a ring structure. The towers are composed of multiple ultra-thin pixel modules stacked on top of each other. Making it possible to perform depth of interaction measurements and maximize the spatial resolution along the line of flight of the two photons emitted within a patient. This will result in improved image quality, contrast, and uniformity while drastically reducing backgrounds within the scanner. Allowing for a reduction in the amount of radioactivity delivered to the patient. Due to an expected data rate of about 250 MB/s a custom readout system for high data throughput has been developed, which includes noise filtering and reduced data pressure. The realisation of a first scanner prototype for small animals is foreseen by 2019. A general overview of the scanner will be given including, technical details concerning the detection elements, mechanics, DAQ readout, simulation and results.
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