1,834 research outputs found
Towards generic satellite payloads: software radio
Satellite payloads are becoming much more complex with the evolution towards multimedia applications. Moreover satellite lifetime increases while standard and services evolve faster, necessitating a hardware platform that can evolves for not developing new systems on each change. The same problem occurs in terrestrial systems like mobile networks and a foreseen solution is the software defined radio technology. In this paper we describe a way of introducing this concept at satellite level to offer to operators the required flexibility in the system. The digital functions enabling this technology, the hardware components implementing the functions and the reconfiguration processes are detailed. We show that elements of the software radio for satellites exist and that this concept is feasible
Upgrade of the ALICE Inner Tracking System
During the Long Shutdown 2 of the LHC in 2018/2019, the ALICE experiment
plans the installation of a novel Inner Tracking System. It will replace the
current six layer detector system with a seven layer detector using Monolithic
Active Pixel Sensors. The upgraded Inner Tracking System will have
significantly improved tracking and vertexing capabilities, as well as readout
rate to cope with the expected increased Pb-Pb luminosity of the LHC. The
choice of Monolithic Active Pixel Sensors has been driven by the specific
requirements of ALICE as a heavy ion experiment dealing with rare processes at
low transverse momenta. This leads to stringent requirements on the material
budget of 0.3 per layer for the three innermost layers. Furthermore,
the detector will see large hit densities of on average for minimum-bias events in the
inner most layer and has to stand moderate radiation loads of 700 kRad TID and
1 MeV n NIEL at maximum. The
Monolithic Active Pixel Sensor detectors are manufactured using the TowerJazz
0.18 m CMOS Imaging Sensor process on wafers with a high-resistivity
epitaxial layer. This contribution summarises the recent R&D activities and
focuses on results on the large-scale pixel sensor prototypes.Comment: 10 pages, 8 figures, proceedings of VERTEX 2014, 15-19 September 201
The upgrade of the ALICE Inner Tracking System
The Inner Tracking System (ITS) of the ALICE experiment will be upgraded
during the second long LHC shutdown in . The main
goal of the ALICE ITS Upgrade is to enable high precision measurements of low -
momentum particles (< 1 GeV/c) by acquiring a large sample of events,
benefiting from the increase of the LHC instantaneous luminosity of
collisions to during Run 3. Working in this direction the ITS upgrade project is
focusing on the increase of the readout rate, on the improvement of the impact
parameter resolution, as well as on the improvement of the tracking efficiency
and the position resolution. The major setup modification is the substitution
of the current ITS with seven layers of silicon pixel detectors. The ALPIDE
chip, a CMOS Monolithic Active Pixel Sensor (MAPS), was developed for this
purpose and offers a spatial resolution of 5 m. The use of MAPS together
with a stringent mechanical design allows for the reduction of the material
budget down to 0.35% for the innermost layers and 1% for the outer
layers. The detector design was validated during the research and development
period through a variety of tests ensuring the proper operation for the full
lifetime inside ALICE. The production phase is close to completion with all the
new assembled components undergoing different tests that aim to characterize
the modules and staves and determine their qualification level. This
contribution describes the detector design, the measurements performed during
the research and development phase, as well as the production status
The digital data processing concepts of the LOFT mission
The Large Observatory for X-ray Timing (LOFT) is one of the five mission
candidates that were considered by ESA for an M3 mission (with a launch
opportunity in 2022 - 2024). LOFT features two instruments: the Large Area
Detector (LAD) and the Wide Field Monitor (WFM). The LAD is a 10 m 2 -class
instrument with approximately 15 times the collecting area of the largest
timing mission so far (RXTE) for the first time combined with CCD-class
spectral resolution. The WFM will continuously monitor the sky and recognise
changes in source states, detect transient and bursting phenomena and will
allow the mission to respond to this. Observing the brightest X-ray sources
with the effective area of the LAD leads to enormous data rates that need to be
processed on several levels, filtered and compressed in real-time already on
board. The WFM data processing on the other hand puts rather low constraints on
the data rate but requires algorithms to find the photon interaction location
on the detector and then to deconvolve the detector image in order to obtain
the sky coordinates of observed transient sources. In the following, we want to
give an overview of the data handling concepts that were developed during the
study phase.Comment: Proc. SPIE 9144, Space Telescopes and Instrumentation 2014:
Ultraviolet to Gamma Ray, 91446
A Radiation-Hard Dual Channel 4-bit Pipeline for a 12-bit 40 MS/s ADC Prototype with extended Dynamic Range for the ATLAS Liquid Argon Calorimeter Readout Electronics Upgrade at the CERN LHC
The design of a radiation-hard dual channel 12-bit 40 MS/s pipeline ADC with
extended dynamic range is presented, for use in the readout electronics upgrade
for the ATLAS Liquid Argon Calorimeters at the CERN Large Hadron Collider. The
design consists of two pipeline A/D channels with four Multiplying
Digital-to-Analog Converters with nominal 12-bit resolution each. The design,
fabricated in the IBM 130 nm CMOS process, shows a performance of 68 dB SNDR at
18 MHz for a single channel at 40 MS/s while consuming 55 mW/channel from a 2.5
V supply, and exhibits no performance degradation after irradiation. Various
gain selection algorithms to achieve the extended dynamic range are implemented
and tested.Comment: 22 pages, 22 figures, accepted by JINS
Development of Novel Sensor Devices for Total Ionization Dose Detection
abstract: Total dose sensing systems (or radiation detection systems) have many applications,
ranging from survey monitors used to supervise the generated radioactive waste at
nuclear power plants to personal dosimeters which measure the radiation dose
accumulated in individuals. This dissertation work will present two different types of
novel devices developed at Arizona State University for total dose sensing applications.
The first detector technology is a mechanically flexible metal-chalcogenide glass (ChG)
based system which is fabricated on low cost substrates and are intended as disposable
total dose sensors. Compared to existing commercial technologies, these thin film
radiation sensors are simpler in form and function, and cheaper to produce and operate.
The sensors measure dose through resistance change and are suitable for applications
such as reactor dosimetry, radiation chemistry, and clinical dosimetry. They are ideal for
wearable devices due to the lightweight construction, inherent robustness to resist
breaking when mechanically stressed, and ability to attach to non-flat objects. Moreover,
their performance can be easily controlled by tuning design variables and changing
incorporated materials. The second detector technology is a wireless dosimeter intended
for remote total dose sensing. They are based on a capacitively loaded folded patch
antenna resonating in the range of 3 GHz to 8 GHz for which the load capacitance varies
as a function of total dose. The dosimeter does not need power to operate thus enabling
its use and implementation in the field without requiring a battery for its read-out. As a
result, the dosimeter is suitable for applications such as unattended detection systems
destined for covert monitoring of merchandise crossing borders, where nuclear material
tracking is a concern. The sensitive element can be any device exhibiting a known
variation of capacitance with total ionizing dose. The sensitivity of the dosimeter is
related to the capacitance variation of the radiation sensitive device as well as the high
frequency system used for reading. Both technologies come with the advantage that they
are easy to manufacture with reasonably low cost and sensing can be readily read-out.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201
Upgrade of the Inner Tracking System of ALICE
The upgrade of the Inner Tracking System (ITS) of ALICE is planned for the
second long shutdown of the LHC in 2019-2020. The ALICE physics program after
the shutdown requires the ITS to have improved tracking capabilities and
improved impact parameter resolution at very low transverse momentum, as well
as a substantial increase in the readout rate. To fulfill these requirements
the current ITS will be replaced by seven layers of Monolithic Active Pixel
Sensors. The new detector will be moved as close as 23 mm to the interaction
point and will have a significantly reduced material budget. Several prototypes
of the sensor have been developed to test different aspects of the sensor
design including prototypes with analog and digital readout, as well as small
and final-size sensors. These prototypes have been thoroughly characterized
both in laboratory tests and at test beam facilities including studies on the
radiation hardness of the sensors. This contribution gives an overview of the
current status of the research and development with a focus on the pixel
sensors and the characterization of the latest prototypes.Comment: 10 pages, 9 figures, proceedings of VERTEX 2015, 1-5 June 2015, Santa
Fe, New Mexico, US
The ALICE TPC, a large 3-dimensional tracking device with fast readout for ultra-high multiplicity events
The design, construction, and commissioning of the ALICE Time-Projection
Chamber (TPC) is described. It is the main device for pattern recognition,
tracking, and identification of charged particles in the ALICE experiment at
the CERN LHC. The TPC is cylindrical in shape with a volume close to 90 m^3 and
is operated in a 0.5 T solenoidal magnetic field parallel to its axis.
In this paper we describe in detail the design considerations for this
detector for operation in the extreme multiplicity environment of central
Pb--Pb collisions at LHC energy. The implementation of the resulting
requirements into hardware (field cage, read-out chambers, electronics),
infrastructure (gas and cooling system, laser-calibration system), and software
led to many technical innovations which are described along with a presentation
of all the major components of the detector, as currently realized. We also
report on the performance achieved after completion of the first round of
stand-alone calibration runs and demonstrate results close to those specified
in the TPC Technical Design Report.Comment: 55 pages, 82 figure
A review of advances in pixel detectors for experiments with high rate and radiation
The Large Hadron Collider (LHC) experiments ATLAS and CMS have established
hybrid pixel detectors as the instrument of choice for particle tracking and
vertexing in high rate and radiation environments, as they operate close to the
LHC interaction points. With the High Luminosity-LHC upgrade now in sight, for
which the tracking detectors will be completely replaced, new generations of
pixel detectors are being devised. They have to address enormous challenges in
terms of data throughput and radiation levels, ionizing and non-ionizing, that
harm the sensing and readout parts of pixel detectors alike. Advances in
microelectronics and microprocessing technologies now enable large scale
detector designs with unprecedented performance in measurement precision (space
and time), radiation hard sensors and readout chips, hybridization techniques,
lightweight supports, and fully monolithic approaches to meet these challenges.
This paper reviews the world-wide effort on these developments.Comment: 84 pages with 46 figures. Review article.For submission to Rep. Prog.
Phy
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