For the Phase-II Upgrade of the ATLAS detector at CERN, the current ATLAS Inner Detector will be replaced with the ATLAS Inner Tracker (ITk). The ITk will be an all-silicon detector, consisting of a ...pixel tracker and a strip tracker. Sensors for the ITk strip tracker are required to have a low leakage current up to bias voltages of −500 V to maintain a low noise and power dissipation. In order to minimise sensor leakage currents, particularly in the high-radiation environment inside the ATLAS detector, sensors are foreseen to be operated at low temperatures and to be manufactured from wafers with a high bulk resistivity of several kΩ·cm. Simulations showed the electric field inside sensors with high bulk resistivity to extend towards the sensor edge, which could lead to increased surface currents for narrow dicing edges. In order to map the electric field inside biased silicon sensors with high bulk resistivity, three diodes from ATLAS silicon strip sensor prototype wafers were studied with a monochromatic, micro-focused X-ray beam at the Diamond Light Source (Didcot, U.K.). For all devices under investigation, the electric field inside the diode was mapped and its dependence on the applied bias voltage was studied.
ATLAS has formed strip CMOS project to study the use of CMOS MAPS devices as silicon strip sensors for the Phase-II Strip Tracker Upgrade. This choice of sensors promises several advantages over the ...conventional baseline design, such as better resolution, less material in the tracking volume, and faster construction speed. At the same time, many design features of the sensors are driven by the requirement of minimizing the impact on the rest of the detector. Hence the target devices feature long pixels which are grouped to form a virtual strip with binary-encoded z position. The key performance aspects are radiation hardness compatibility with HL-LHC environment, as well as extraction of the full hit position with full-reticle readout architecture. To date, several test chips have been submitted using two different CMOS technologies. The AMS 350nm is a high voltage CMOS process (HV-CMOS), that features the sensor bias of up to 120V. The TowerJazz 180nm high resistivity CMOS process (HR-CMOS) uses a high resistivity epitaxial layer to provide the depletion region on top of the substrate. We have evaluated passive pixel performance, and charge collection projections. The results strongly support the radiation tolerance of these devices to radiation dose of the HL-LHC in the strip tracker region. We also describe design features for the next chip submission that are motivated by our technology evaluation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Food sovereignty promotes agroecological farming methods and the reduction of food insecurity through changing political relations between people, land and food policy. Market orientations to land ...and private property in liberal democracies restrict access to food, and thus for food sovereigntists, reframing the social relationship to land through property is key to making food more available. This paper examines the case of usufruct land rights in Cuba as a framework for reworking land rights. We identify key limitations that impair producer autonomy, suggesting how different orientations toward property present unique problems and potential solutions towards the goal of food sovereignty.
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BFBNIB, NUK, PILJ, SAZU, UL, UM, UPUK
The Hospital Survey on Patient Safety was used to identify opportunities for safety culture improvement in a 30‐bed intensive care unit. Based on the survey results, a core team decided to focus on ...three safety domains: reporting errors, approachability of authority figures and handovers. The project team subsequently interviewed 39 intensive care unit staff members, gathering information on these three domains that will inform future safety efforts. Numerous barriers and facilitators to improvement were described. This mixed‐methods approach could be applied in other hospitals seeking to quickly yet thoroughly understand how their safety culture can be improved. Developing local strategies to reduce these barriers may promote a safer patient experience at our hospital.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK, VSZLJ
Monolithic complementary metal oxide semiconductor (CMOS) active pixel sensors with high performance have gained attention in the last few years in many scientific and space applications. In order to ...evaluate the increasing capabilities of this technology, in particular where low dose high resolution x-ray medical imaging is required, critical electro-optical and physical x-ray performance evaluation was determined. The electro-optical performance includes read noise, full well capacity, interacting quantum efficiency, and pixels cross talk. The x-ray performance, including x-ray sensitivity, modulation transfer function, noise power spectrum, and detection quantum efficiency, has been evaluated in the mammographic energy range. The sensor is a
525
×
525
standard three transistor CMOS active pixel sensor array with more than 75% fill factor and
25
×
25
μ
m
pixel
pitch. Reading at
10
f
∕
s
, it is found that the sensor has 114 electrons total additive noise,
10
5
electrons full well capacity with shot noise limited operation, and 34% interacting quantum efficiency at
530
nm
. Two different structured CsI:Tl phosphors with thickness 95 and
115
μ
m
, respectively, have been optically coupled via a fiber optic plate to the array resulting in two different system configurations. The sensitivity of the two different system configurations was 43 and 47 electrons per x-ray incident on the sensor. The MTF at 10% of the two different system configurations was 9.5 and
9
cycles
∕
mm
with detective quantum efficiency of 0.45 and 0.48, respectively, close to zero frequency at
∼
0.44
μ
C
∕
kg
(
1.72
mR
)
detector entrance exposure. The detector was quantum limited at low spatial frequencies and its performance was comparable with high resolution
a
:
Si
and charge coupled device based x-ray imagers. The detector also demonstrates almost an order of magnitude lower noise than active matrix flat panel imagers. The results suggest that CMOS active pixel sensors when coupled to structured CsI:Tl can be used for conventional and advanced digital mammography due to their low noise, high resolution performance.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
With child migration on the rise, there is a critical need to understand how migrant children express their agency. To date, popular narratives cast migrant children as either victims or criminals, ...an unhelpful binary that does little to further efforts to develop effective interventions to help migrant youth. Drawing from 32 in-depth interviews and participatory activities with Mexican and Central American children in Mexican youth immigration detention centres, this paper seeks to reconceptualise current understandings of migrant children's agency. In this paper, we explore how youth express their motivations, assert their will, develop pragmatic dependencies, employ strategic parroting and guard information to achieve their goals. We also examine how state and non-state actors both support and suppress young people's agency as they try to navigate their way to the U.S./Mexico border. In doing so, we argue for a more nuanced approach to child migrants' agency. A non-binary approach recognises the development of agency as a process, embracing children and young people's rights and vulnerabilities, while acknowledging their resiliencies, competencies, goals and strengths. We conclude by proposing a transdisciplinary research agenda to promote this non-binary approach.
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BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
28.
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
Scribe–cleave–passivate (SCP) slim edge technology for silicon sensors Fadeyev, V.; Sadrozinski, H.F.-W.; Ely, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2013, Volume:
731
Journal Article
Peer reviewed
We are pursuing scribe–cleave–passivate (SCP) technology of making “slim edge” sensors. Such sensors have only a minimal amount of inactive peripheral region, which benefits construction of ...large-area tracker and imaging systems. Key application steps of this method are surface scribing, cleaving, and passivation of the resulting sidewall. We are working on developing both the technology and physical understanding of the processed devices performance. In this paper we begin by reviewing the manufacturing options of SCP technology. Then we show new results regarding the technology automation and device physics performance. The latter includes charge collection efficiency near the edge and radiation hardness study. We also report on the status of devices processed at the request of the RD50 collaborators.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Inadequate sleep is an on-going risk to the health and mission readiness of U.S. Armed Forces, with estimates of sleep problems high above U.S. civilian populations. Intervening early in the career ...of active duty Air Force personnel (or "Airmen") with education and the establishment of healthy behaviors may prevent short and long term-detriments of sleep problems. This paper describes the results of a qualitative study seeking to understand the facilitators and barriers to achieving good sleep in a technical training school during the first year of entry into the United States Air Force. Using the social ecological framework and content analysis, three focus groups with Airmen were conducted to explore themes at the individual, social, environmental, and organizational/policy level. Overall, results indicated a cohort motivated to achieve good sleep, and also struggling with a number of barriers across each level. This paper highlights opportunities for population health interventions during technical training aimed at supporting Airmen in developing healthy sleep behaviors early in the course of their career.
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