31468812
Test results of the Data Handling Processor for the DEPFET Pixel Vertex Detector
In the new Belle II detector, which is currently under construction at the SuperKEKB accelerator, a two layer pixel detector will be introduced to improve the vertex reconstruction in a ultra high luminosity environment. The pixel detector will be produced using the DEPFET technology. A new ASIC (Data Handling Processor or DHP) designed to steer the readout process, pre-process and compress the raw data has been developed. The DHP will be directly bump bonded to the balcony of the all-silicon DEPFET module. The current chip prototype has been produced in CMOS 90 nm. Its test results, including the data processing quality, the signal integrity of the gigabit transmission lines will be presented here. For the final chip, which will be produced using CMOS 65 nm, single event upset (SEU) cross sections were measured. An additional chip, containing memory blocks to be tested, was submitted and produced using this technology.
22518405
Performance of a DEPFET prototype module for the ILC vertex detector
For the detection of secondary vertices of long lived bottom and charm quarks at the proposed International Linear Collider (ILC) a DEPFET pixel detector is one of the favored technology options. DEPFET pixel sensors, in which the amplifying transistor structure is contained in the pixel cell itself on a fully depleted bulk, are unique devices in terms of their large signal and low noise capability and their obtainable spatial resolution with very thin detectors. DEPFET pixel prototype modules with close to ILC specifications have been tested in the laboratory and, for the first time, in a 6 GeV electron test beam. The different noise sources have been calculated and compared with the measured value of ENC/spl ap/225 e/sup -/ for the entire readout chain.
59369355
DMAPS: a fully depleted monolithic active pixel sensor—analog performance characterization
Monolithic Active Pixel Sensors (MAPS) have been developed since the late 1990s based on silicon substrates with a thin epitaxial layer (thickness of 10–15 μm) in which charge is collected on an electrode, albeit by disordered and slow diffusion rather than by drift in a directed electric field. As a consequence, the signal of these conventional MAPS is small (≈1000 e−) and the radiation tolerance is limited. In this paper, the development of a fully Depleted Monolithic Active Pixel Sensors (DMAPS) based on a high resistivity substrate allowing the creation of a fully depleted detection volume is presented. This concept overcomes the inherent limitations of charge collection by diffusion in the standard MAPS designs. We present results from a prototype chip EPCB01 designed in a commercial 150 nm CMOS technology. The technology provides a thin (≈50 μm) high resistivity n-type silicon substrate as well as an additional deep p-well which allows to integrate full CMOS circuitry inside the pixel. Different matrix types with several variants of collection electrodes and pixel electronics have been implemented. Measurements of the analog performance of this first implementation of DMAPS pixels are presented.
123566403
Search for squarks and gluinos with the ATLAS detector in final states with jets and missing transverse momentum using 4.7 fb-1 of √s = 7 TeV proton-proton collision data
A search for squarks and gluinos in final states containing jets, missing transverse momentum and no high-p(T) electrons or muons is presented. The data represent the complete sample recorded in 2011 by the ATLAS experiment in 7 TeV proton-proton collisions at the Large Hadron Collider, with a total integrated luminosity of 4.7 fb(-1). No excess above the Standard Model background expectation is observed. Gluino masses below 860 GeV and squark masses below 1320 GeV are excluded at the 95% confidence level in simplified models containing only squarks of the first two generations, a gluino octet and a massless neutralino, for squark or gluino masses below 2 TeV, respectively. Squarks and gluinos with equal masses below 1410 GeV are excluded. In minimal supergravity/constrained minimal supersymmetric Standard Model models with tan beta = 10, A(0) = 0 and mu > 0, squarks and gluinos of equal mass are excluded for masses below 1360 GeV. Constraints are also placed on the parameter space of supersymmetric models with compressed spectra. These limits considerably extend the region of supersymmetric parameter space excluded by previous measurements with the ATLAS detector.
36714686
A Tezzaron-Chartered 3D-IC electronic for SLHC/ATLAS hybrid pixels detectors test results and irradiations performance
The ATLAS pixel collaboration has started in 2008 a R&D program to use the latest advances in 3-D electronics technology in order to develop a new Front-End (FE) chip for a vertex detector for High Energy Physics (HEP). This program using the commercial Tezzaron-Chartered 0.13µm LP technology should be able to fulfill the requirements imposed by the ten times higher luminosity given by the High Luminosity LHC accelerator. The FE-TC4-P1 is a hybrid pixel read-out chip realized by the first MPW for HEP. This three dimensional chip includes an analog part called FE-TC4-AE and two digital parts called FE-TC4-DS and FE-TC4-DC. At the same time, several prototypes were realized in Chartered 0.13µm LP technology, in order to disentangle from effects induced by 3D architecture. These FE-C4-P1,2,3 prototypes have proved a good radiation hardness up to 400Mrads as well as good performances. This paper presents results from the FE-TC4-P1 chip which has been recently tested and irradiated.
3052728
A DEPFET Based Beam Telescope With Submicron Precision Capability
For the detection of secondary vertices of long lived particles containing bottom and charm quarks at the International Linear Collider (ILC), a DEPFET pixel detector is one of the technologically favored options. In a DEPFET sensor a MOSFET pixel detector is integrated on a sidewards depleted silicon bulk sensor, thus combining the advantages of a fully depleted silicon sensor with in-pixel amplification. DEPFET pixel matrices have been characterized in a high energy particle beam. Since the DEPFET is a very high precision device, given its large S/N (> 100) and small pixel size (36 × 22 ¿m2), a DEPFET based pixel telescope consisting of 5 DEPFETs has been developed. The uncertainty on the predicted position for a device under test (DUT) positioned inside the telescope was found to be 1.4 ¿m with the existing device, due to the limited performance of two of the five DEPFET planes. A DEPFET telescope built of 5 modules equivalent to the best plane presented here, would have a track extrapolation error as low as 0.65 ¿m at the DUT plane.
2761770
Jovian dust streams: A monitor of Io's volcanic plume activity
[1] Streams of high speed dust particles originate from Jupiter's moon Io. After release from Io, the particles collect electric charges in the Io plasma torus, gain energy from the co-rotating electric field of Jupiter's magnetosphere, and leave the Jovian system into interplanetary space with escape speeds over 200 km s−1. The Galileo spacecraft has continuously monitored the dust streams during 34 revolutions about Jupiter between 1996 and 2002. The observed dust fluxes exhibit large orbit-to-orbit variability due to systematic and stochastic changes. After removal of the systematic variations, the total dust emission rate of Io has been calculated. It varies between 10−3 and 10 kg s−1, and is typically in the range of 0.1 to 1 kg s−1. We compare the dust emission rate with other markers of volcanic activity on Io like large-area surface changes caused by volcanic deposits and sightings of volcanic plumes.
56343042
Polarization of Σ+ hyperons produced by 800 GeV/c protons on Cu and Be
We show that {sigma}{sup +} hyperons produced by 800 GeV/c protons on targets of Be and Cu have significant polarizations (15-20%). These polarizations persist at values of p{sub t}{approx_equal}2 GeV/c and a wide range of x{sub F}. The polarizations from the Cu target are consistently less than from Be. The average ratio of the {sigma}{sup +} polarization from Cu to that from Be is 0.68{+-}0.08.
119408500
Observations of Electromagnetically Coupled Dust in the Jovian Magnetosphere
We report on dust measurements obtained during the seventh orbit of the Galileo spacecraft about Jupiter. The most prominent features observed are highly time variable dust streams recorded throughout the Jovian system. The impact rate varied by more than an order of magnitude with a 5 and 10 hour periodicity, which shows a correlation with Galileo's position relative to the Jovian magnetic field. This behavior can be qualitatively explained by strong coupling of nanometer-sized dust to the Jovian magnetic field. In addition to the 5 and 10 h periodicities, a longer period which is compatible with Io's orbital period is evident in the dust impact rate. This feature indicates that Io most likely is the source of the dust streams. During a close (3,095 km altitude) flyby at Ganymede on 5 April 1997 an enhanced rate of dust impacts has been observed, which suggests that Ganymede is a source of ejecta particles. Within a distance of about 25 RJ(Jupiter radius, RJ= 71,492 km) from Jupiter impacts of micrometer-sized particles have been recorded which could be particles on bound orbits about Jupiter.