Investigation of thin n-in-p planar pixel modules for the ATLAS upgrade

In view of the High Luminosity upgrade of the Large Hadron Collider (HL-LHC), planned to start around 2023-2025, the ATLAS experiment will undergo a replacement of the Inner Detector. A higher luminosity will imply higher irradiation levels and hence will demand more ra- diation hardness especially in the inner layers of the pixel system. The n-in-p silicon technology is a promising candidate to instrument this region, also thanks to its cost-effectiveness because it only requires a single sided processing in contrast to the n-in-n pixel technology presently employed in the LHC experiments. In addition, thin sensors were found to ensure radiation hardness at high fluences. An overview is given of recent results obtained with not irradiated and irradiated n-in-p planar pixel modules. The focus will be on n-in-p planar pixel sensors with an active thickness of 100 and 150 um recently produced at ADVACAM. To maximize the active area of the sensors, slim and active edges are implemented. The performance of these modules is investigated at beam tests and the results on edge efficiency will be shown

ATLAS IBL Pixel Upgrade

The upgrade for ATLAS detector will undergo different phase towards super-LHC. The first upgrade for the Pixel detector will consist of the construction of a new pixel layer which will be installed during the first shutdown of the LHC machine (LHC phase-I upgrade). The new detector, called Insertable B-Layer (IBL), will be inserted between the existing pixel detector and a new (smaller radius) beam-pipe at a radius of 3.3 cm. The IBL will require the development of several new technologies to cope with increase of radiation or pixel occupancy and also to improve the physics performance which will be achieved by reducing the pixel size and of the material budget. Three different promising sensor technologies (planar-Si, 3D-Si and diamond) are currently under investigation for the pixel detector. An overview of the project with particular emphasis on pixel module is presented in this paper.Comment: 3 pages, 3 figures, presented at the 12th Topical Seminar on Innovative Particle and Radiation Detectors (IPRD10) 7 - 10 June 2010, Siena (IT). Accepted by Nuclear Physics B (Proceedings Supplements) (2011

SPIDER X - Environmental effects in central and satellite early-type galaxies through the stellar fossil record

A detailed analysis of how environment affects the star formation history of early-type galaxies (ETGs) is undertaken via high signal to noise ratio stacked spectra obtained from a sample of 20,977 ETGs (morphologically selected) from the SDSS-based SPIDER survey. Two major parameters are considered for the study: the central velocity dispersion (sigma), which relates to local drivers of star formation, and the mass of the host halo, which relates to environment-related effects. In addition, we separate the sample between centrals (the most massive galaxy in a halo) and satellites. We derive trends of age, metallicity, and [alpha/Fe] enhancement, with sigma. We confirm that the major driver of stellar population properties in ETGs is velocity dispersion, with a second-order effect associated to the central/satellite nature of the galaxy. No environmental dependence is detected for satellite ETGs, except at low sigma - where satellites in groups or in the outskirts of clusters tend to be younger than those in the central regions of clusters. In contrast, the trends for centrals show a significant dependence on halo mass. Central ETGs in groups (i.e. with a halo mass >10^12.5 M_Sun) have younger ages, lower [alpha/Fe], and higher internal reddening, than "isolated" systems (i.e. centrals residing in low-mass, <10^12.5 M_Sun, halos). Our findings imply that central ETGs in groups formed their stellar component over longer time scales than "isolated" centrals, mainly because of gas-rich interactions with their companion galaxies.Comment: 22 pages, 19 figures, accepted for publication in MNRA

Performance of novel silicon n-in-p planar Pixel Sensors

The performance of novel n-in-p planar pixel detectors, designed for future upgrades of the ATLAS Pixel system is presented. The n-in-p silicon sensors technology is a promising candidate for the pixel upgrade thanks to its radiation hardness and cost effectiveness, that allow for enlarging the area instrumented with pixel detectors. The n-in-p modules presented here are composed of pixel sensors produced by CiS connected by bump-bonding to the ATLAS readout chip FE-I3. The characterization of these devices has been performed before and after irradiation up to a fluence of 5 x 10**15 1 MeV neq cm-2 . Charge collection measurements carried out with radioactive sources have proven the functioning of this technology up to these particle fluences. First results from beam test data with a 120 GeV/c pion beam at the CERN-SPS are also discussed, demonstrating a high tracking efficiency of (98.6 \pm 0.3)% and a high collected charge of about 10 ke for a device irradiated at the maximum fluence and biased at 1 kV.Comment: Preprint submitted to Nuclear Instruments and Methods A. 7 pages, 13 figure

High resolution radio study of the Pulsar Wind Nebula within the Supernova Remnant G0.9+0.1

We have conducted a radio study at 3.6, 6 and 20 cm using ATCA and VLA and reprocessed XMM-Newton and Chandra data of the pulsar wind nebula (PWN) in the supernova remnant (SNR) G0.9+0.1. The new observations revealed that the morphology and symmetry suggested by Chandra observations (torus and jet-like features) are basically preserved in the radio range in spite of the rich structure observed in the radio emission of this PWN, including several arcs, bright knots, extensions and filaments. The reprocessed X-ray images show for the first time that the X-ray plasma fills almost the same volume as the radio PWN. Notably the X-ray maximum does not coincide with the radio maximum and the neutron star candidate CXOU J174722.8-280915 lies within a small depression in the radio emission. From the new radio data we have refined the flux density estimates, obtaining S(PWN) ~ 1.57 Jy, almost constant between 3.6 and 20 cm. For the whole SNR (compact core and shell), a flux density S(at 20 cm)= 11.5 Jy was estimated. Based on the new and the existing 90 cm flux density estimates, we derived alpha(PWN)=-0.18+/-0.04 and alpha(shell)=-0.68+/- 0.07. From the combination of the radio data with X-ray data, a spectral break is found near nu ~ 2.4 x 10^(12) Hz. The total radio PWN luminosity is L(radio)=1.2 x 10^(35) erg s^(-1) when a distance of 8.5 kpc is adopted. By assuming equipartition between particle and magnetic energies, we estimate a nebular magnetic field B = 56 muG. The associated particle energy turns out to be U(part)=5 x 10^(47) erg and the magnetic energy U(mag)=2 x 10^(47) erg. Based on an empirical relation between X-ray luminosity and pulsar energy loss rate, and the comparison with the calculated total energy, a lower limit of 1100 yr is derived for the age of this PWN.Comment: 10 pages,8 figures, accepted for publication in A&A, June 13 200