The ALICE Zero Degree Calorimeters (ZDC) provide information about event geometry in heavy-ion collisions through the detection of spectator nucleons and allow to estimate the delivered luminosity. ...They are also very useful in p–A collisions, allowing an unbiased estimation of collision centrality. The Run 3 operating conditions will involve a tenfold increase in instantaneous luminosity in heavy-ion collisions, with event rates that, taking into account the different processes, could reach 5 MHz in the ZDCs. The challenges posed by this demanding environment lead to a redesign of the readout system and to the transition to a continuous acquisition. The new system is based on 12 bit, 1 Gsps FMC digitizers that will continuously sample the 26 ZDC channels. Triggering, pedestal estimation and luminosity measurements will be performed on FPGA directly connected to the front-end. The new readout system and the performances foreseen in Run 3 are presented.
The Pixel Chamber project purpose is the production of the first solid state active target capable of performing continuous, high-resolution (O(μm)) 3D tracking. The aim is to create a bubble ...chamber-like high-granularity stack of hundreds of very thin monolithic active pixel sensors (MAPS) glued together. In this paper, the R&D to develop the first prototypes with ALPIDE sensors, designed for the ALICE experiment at the CERN LHC, will be presented. Tracking and vertexing algorithms were developed to reconstruct tracks and vertices inside Pixel Chamber. They were tested on Monte Carlo simulations which show that it is possible to obtain a high efficiency for the reconstruction of hadronic tracks, and for the primary and secondary vertices inside the detector. The tracking algorithm has been tested on test beam data to reconstruct long tracks produced in a single ALPIDE sensor parallel to a beam. Results show that it is possible to obtain very good performances in long track reconstruction on a single ALPIDE. Among the possible applications, Pixel Chamber used as an active target, has the potential to allow precision measurements of charm and beauty production. Even more interesting are possible medical and astrophysical applications. The usage of the Pixel Chamber as scatterer detector in Compton Cameras would reduce by orders of magnitude the numbers of gammas required for performing a precise source imaging, both for in vivo monitoring during hadron therapy and for astrophysics measurements.
Abstract
The aim of the pixel chamber project is to develop the first “solid-state bubble chamber” for high precision measurement of charm and beauty. In this paper we will describe the idea for the ...first silicon active target conceived as an ultra-high granular stack of hundreds of very thin monolithic active pixel sensors (MAPS), which provides continuous, high-resolution 3D tracking of all of the particles produced in proton-silicon interactions occurring inside the detector volume, including open charm and beauty. We will also discuss the high-precision tracking and vertexing performances, showing that the vertex resolution can be up to one order of magnitude better than state-of-the-art detectors like the LHCb one.
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.
In the present article, a simple two-step technique for synthesis of electrically conducting hydrogel is described. The synthesized hydrogel is originally a semi-interpenetrating polymer network ...(IPN) in which conducting polyaniline (linear) is entrapped within a crosslinked polyelectrolyte gel viz. poly(2-acrylamido-2-methyl propane sulphonic acid) (PAMPS). A conventional photo-polymerization technique was followed for synthesis of the PAMPS gel while aniline is in situ polymerized within the gel, giving rise to the desired semi-IPN. For comparison, a neutral gel based semi-IPN PAn–PAAm (polyaniline–polyacrylamide) was also prepared following the similar route. PAn imparts appreciable electrical conductivity to both PAMPS and PAAm based gels without hampering their existing properties that indicates the success of the work. Synthesis of the gel was studied in detail and different experimental conditions were optimized. Different physical properties of the gel viz. its degree of swelling, electrical conductivity, mechanical strength, etc were also studied. The resultant semi-IPN or the composite hydrogel was found to possess appreciable electrical conductivity, good swellability and mechanical strength. The electro-driven volume contraction of the composite gel was found to occur at sufficiently lower voltage compared to the pure PAMPS gel, which indicates its promising application aspect in fabrication of chemomechanical devices.
ALICE plans to replace its Inner Tracking System during the second long shut down of the LHC in 2019 with a new 10 m super(2) tracker constructed entirely with monolithic active pixel sensors. The ...TowerJazz 180 nm CMOS imaging Sensor process has been selected to produce the sensor as it offers a deep pwell allowing full CMOS in-pixel circuitry and different starting materials. First full-scale prototypes have been fabricated and tested. Radiation tolerance has also been verified. In this paper the development of the charge sensitive front end and in particular its optimization for uniformity of charge threshold and time response will be presented.
ALICE plans an upgrade of its Inner Tracking System for 2018. The development of a monolithic active pixel sensor for this upgrade is described. The TowerJazz 180 nm CMOS imaging sensor process has ...been chosen as it is possible to use full CMOS in the pixel due to the offering of a deep pwell and also to use different starting materials. The ALPIDE development is an alternative to approaches based on a rolling shutter architecture, and aims to reduce power consumption and integration time by an order of magnitude below the ALICE specifications, which would be quite beneficial in terms of material budget and background. The approach is based on an in-pixel binary front-end combined with a hit-driven architecture. Several prototypes have already been designed, submitted for fabrication and some of them tested with X-ray sources and particles in a beam. Analog power consumption has been limited by optimizing the Q/C of the sensor using Explorer chips. Promising but preliminary first results have also been obtained with a prototype ALPIDE. Radiation tolerance up to the ALICE requirements has also been verified.
Bisphosphonates have anti-inflammatory properties in arthritic conditions. This study was conducted to assess the therapeutic potential of intravenous pamidronate in nonsteroidal anti-inflammatory ...drug (NSAID) refractory/intolerant cases of ankylosing spondylitis (AS).
A total of 35 NSAID refractory/intolerant AS patients with Bath AS Disease Activity Index (BASDAI) score 4 or above were recruited for the study. Monthly pamidronate infusions (60 mg) were administered to the patients for six months. Treatment outcomes were assessed by comparing baseline values with the values after six infusions using BASDAI, Bath AS Functional Index (BASFI), Metrology Index (BASMI) and Global Score (BAS-G), C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). An improvement was defined according to the Assessments in Ankylosing Spondylitis (ASAS)-20 and BASDAI-50.
26 patients received all the six infusions. Of these, 22 (85 percent) achieved ASAS-20 and 20 (77 percent) achieved BASDAI-50 responses. Decrements were noted in the mean BASDAI (56.4 percent), BASFI (52.66 percent), BASMI (55.72 percent), BAS-G (66.71 percent), ESR (52.12 percent) and CRP (72.84 percent) after six months. The tender and swollen joint counts of 14 (54 percent) patients with peripheral arthritis were respectively reduced to a mean value of 0.85 and nil, from the baseline of 2.57 and 1.2. Early feel good response was noted in 16 (62 percent) patients within 48 hours of the first infusion. Fever, arthralgia and myalgia were observed in six cases after the first infusion, and in one case, after the second infusion. These symptoms resolved spontaneously within 24 hours.
Intravenous pamidronate has good efficacy for the treatment of AS.
Monolithic Active Pixel Sensors (MAPS) offer the possibility to build pixel detectors and tracking layers with high spatial resolution and low material budget in commercial CMOS processes. ...Significant progress has been made in the field of MAPS in recent years, and they are now considered for the upgrades of the LHC experiments. This contribution will focus on MAPS detectors developed for the ALICE Inner Tracking System (ITS) upgrade and manufactured in the TowerJazz 180 nm CMOS imaging sensor process on wafers with a high resistivity epitaxial layer. Several sensor chip prototypes have been developed and produced to optimise both charge collection and readout circuitry. The chips have been characterised using electrical measurements, radioactive sources and particle beams. The tests indicate that the sensors satisfy the ALICE requirements and first prototypes with the final size of 1.5 x 3 cm super(2) have been produced in the first half of 2014. This contribution summarises the characterisation measurements and presents first results from the full-scale chips.
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