Radiation hard Depleted Monolithic Active Pixel Sensors with high-resistivity substrates

High Voltage/High resistivity Depleted Monolithic Active Pixel Sensors (HV/HR-DMAPS) is a technology which is becoming of great interest for high energy physics applications.With respect to hybrid pixel detectors the monolithic approach offers the main advantages of reduced material budget and production costs due to the absence of the bump bonding process. This aspect is important especially when large areas need to be covered as in the tracking detectors of the LHC experiments. Thus, the possibility of employing this technology in the outermost layers of the upgraded ATLAS pixel detector at the HL-LHC is being investigated.Different HR/HV-DMAPS prototypes have been recently developed for the future ATLAS Inner Tracker (ITk) with the aim of studying their radiation hardness and the feasibility of producing large area devices.The H35DEMO is a large area demonstrator chip for the ITk designed by KIT, IFAE and University of Liverpool and produced in AMS 350 nm HV-CMOS technology with an engineering run on four different substrate resistivities: 20, 80, 200 and 1000 $\mathrm{\Omega cm}$. It consists of four large matrices, two of which include digital electronics and are thus fully monolithic. One, called CMOS matrix, has comparators made of CMOS transistors in the periphery only, while the other, called NMOS matrix, includes also comparators made of NMOS transistors directly in the pixels. The other two matrices have only analog front-end electronics and are meant to be coupled to ATLAS FE-I4 chips. All matrices feature pixels with a size of $\mathrm{(50\times250)\;\mu m^2}$ in which the analog electronics are embedded in a Deep N-WELL (DNWELL) also acting as collecting electrode.A Data Acquisition (DAQ) system was developed at IFAE to read out and test the monolithic matrices of the H35DEMO both in the laboratory and with beam test experiments. H35DEMO chips with a resistivity of 200 $\mathrm{\Omega cm}$ have been irradiated with reactor neutrons to a particle fluence of $1\times10^{15}$ $\mathrm{1\;MeV\;n_{eq}/cm^2}$, the expected fluence for the outermost pixel layer of ITk. The monolithic CMOS matrix of the H35DEMO chip was extensively characterised before and after irradiation in beam tests at Fermilab and DESY, with proton and electron beams, respectively.Results after irradiation show good performance in terms of hit efficiency with thresholds of about 1800 e and a bias voltage of 150 V.Another production of monolithic HV-CMOS prototypes in LFoundry 150 nm technology (LF2) has been recently completed. It includes sensors with a similar DNWELL concept as the H35DEMO but with a smaller pixel size of $\mathrm{(50\times50)\;\mu m^2}$. Preliminary measurements of leakage current of the LF2 chips have been preformed showing good agreement with what expected from the foundry process

Exact solution of a t-J chain with impurity

We study the effects of an integrable impurity in a periodic t-J chain. The impurity couples to both spin and charge degrees of freedom and has the interesting feature that the interaction with the bulk can be varied continuously without losing integrability. We first consider ground state properties close to half-filling in the presence of a small bulk magnetic field. We calculate the impurity contributions to the (zero temperature) susceptibilities and the low temperature specific heat and determine the high-temperature characteristics of the impurity. We then investigate transport properties by computing the spin and charge stiffnesses at zero temperature. Finally the impurity phase--shifts are calculated and the existence of an impurity bound state in the holon sector is established.Comment: 33 pages Latex, figures include

Integrable impurity in the supersymmetric t-J model

An impurity coupling to both spin and charge degrees of freedom is added to a periodic t-J chain such that its interaction with the bulk can be varied continuously without losing integrability. Ground state properties, impurity contributions to the susceptibilities and low temperature specific heat are studied as well as transport properties. The impurity phase--shifts are calculated to establish the existence of an impurity bound state in the holon sector.Comment: RevTeX+epsf macros, 4pp. including 4 figure

PRENOLIN project. Results of the validation phase at sendai site

One of the objectives of the PRENOLIN project is the assessment of uncertainties associated with non-linear simulation of 1D site effects. An international benchmark is underway to test several numerical codes, including various non-linear soil constitutive models, to compute the non-linear seismic site response. The preliminary verification phase (i.e. comparison between numerical codes on simple, idealistic cases) is now followed by the validation phase, which compares predictions of such numerical estimations with actual strong motion data recorded from well-known sites. The benchmark presently involves 21 teams and 21 different non-linear computations. Extensive site characterization was performed at three sites of the Japanese KiK-net and PARI networks. This paper focuses on SENDAI site. The first results indicate that a careful analysis of the data for the lab measurement is required. The linear site response is overestimated while the non-linear effects are underestimated in the first iteration. According to these observations, a first set of recommendations for defining the non-linear soil parameters from lab measurements is proposed. PRENOLIN is part of two larger projects: SINAPS@, funded by the ANR (French National Research Agency) and SIGMA, funded by a consortium of nuclear operators (EDF, CEA, AREVA, ENL)

Gαi2- and Gαi3-Specific Regulation of Voltage-Dependent L-Type Calcium Channels in Cardiomyocytes

BACKGROUND: Two pertussis toxin sensitive G(i) proteins, G(i2) and G(i3), are expressed in cardiomyocytes and upregulated in heart failure. It has been proposed that the highly homologous G(i) isoforms are functionally distinct. To test for isoform-specific functions of G(i) proteins, we examined their role in the regulation of cardiac L-type voltage-dependent calcium channels (L-VDCC). METHODS: Ventricular tissues and isolated myocytes were obtained from mice with targeted deletion of either Gα(i2) (Gα(i2) (-/-)) or Gα(i3) (Gα(i3) (-/-)). mRNA levels of Gα(i/o) isoforms and L-VDCC subunits were quantified by real-time PCR. Gα(i) and Ca(v)α(1) protein levels as well as protein kinase B/Akt and extracellular signal-regulated kinases 1/2 (ERK1/2) phosphorylation levels were assessed by immunoblot analysis. L-VDCC function was assessed by whole-cell and single-channel current recordings. RESULTS: In cardiac tissue from Gα(i2) (-/-) mice, Gα(i3) mRNA and protein expression was upregulated to 187 ± 21% and 567 ± 59%, respectively. In Gα(i3) (-/-) mouse hearts, Gα(i2) mRNA (127 ± 5%) and protein (131 ± 10%) levels were slightly enhanced. Interestingly, L-VDCC current density in cardiomyocytes from Gα(i2) (-/-) mice was lowered (-7.9 ± 0.6 pA/pF, n = 11, p<0.05) compared to wild-type cells (-10.7 ± 0.5 pA/pF, n = 22), whereas it was increased in myocytes from Gα(i3) (-/-) mice (-14.3 ± 0.8 pA/pF, n = 14, p<0.05). Steady-state inactivation was shifted to negative potentials, and recovery kinetics slowed in the absence of Gα(i2) (but not of Gα(i3)) and following treatment with pertussis toxin in Gα(i3) (-/-). The pore forming Ca(v)α(1) protein level was unchanged in all mouse models analyzed, similar to mRNA levels of Ca(v)α(1) and Ca(v)β(2) subunits. Interestingly, at the cellular signalling level, phosphorylation assays revealed abolished carbachol-triggered activation of ERK1/2 in mice lacking Gα(i2). CONCLUSION: Our data provide novel evidence for an isoform-specific modulation of L-VDCC by Gα(i) proteins. In particular, loss of Gα(i2) is reflected by alterations in channel kinetics and likely involves an impairment of the ERK1/2 signalling pathway

Numerical study of 1D/2D wave propagation in the Mygnodian basin, EUROSEISTEST, Northern Greece

International audienceThe E2VP-1 international benchmark ( EUROSEISTEST Verification and Validation Project , 2005-2008) aimed at (i) evaluating accuracy of the numerical methods for seismic simulations of realistic 2D/3D basin models, and (ii) quantitatively comparing the recorded and numerically simulated earthquake ground motions. In this framework, the EUROSEISTEST located in the Mygdonian basin of the Volvi area, near Thessaloniki (Northern Greece) was chosen as target site. In this paper, we present the results obtained for the 2D linear case, for three different numerical schemes finite elements, spectral elements, and finite differences methods. We also compare the 2D results with linear and nonlinear 1D results obtained for soil columns extracted in the middle and the edge of the 2D basin profile.Le benchmark international E2VP-1 (« EUROSEISTEST Verification and Validation Project », 2005-2008) avaitpour principaux objectifs d’évaluer la précision des méthodes numériques pour simuler la réponse sismique 2D/3D debassins sédimentaires, en comparant de manière quantitative, les réponses enregistrées et calculées. Dans ce cadre, il a étéchoisi d’utiliser le site EUROSEISTEST situé dans le bassin Mygdonien de la région de Volvi, proche de Thessalonique(Grèce). Dans cet article, nous présentons les résultats obtenus pour le cas linéaire 2D, avec 3 méthodes numériques :différences finies, éléments finis et éléments spectraux. Nous comparons également les résultats 2D avec les résultatslinéaires et non linéaires 1D obtenus sur 2 colonnes de sol extraites en bord et milieu du profil 2

Numerical study of 1D/2D wave propagation in the Mygnodian basin, EUROSEISTEST, Northern Greece

International audienceThe E2VP-1 international benchmark ( EUROSEISTEST Verification and Validation Project , 2005-2008) aimed at (i) evaluating accuracy of the numerical methods for seismic simulations of realistic 2D/3D basin models, and (ii) quantitatively comparing the recorded and numerically simulated earthquake ground motions. In this framework, the EUROSEISTEST located in the Mygdonian basin of the Volvi area, near Thessaloniki (Northern Greece) was chosen as target site. In this paper, we present the results obtained for the 2D linear case, for three different numerical schemes finite elements, spectral elements, and finite differences methods. We also compare the 2D results with linear and nonlinear 1D results obtained for soil columns extracted in the middle and the edge of the 2D basin profile.Le benchmark international E2VP-1 (« EUROSEISTEST Verification and Validation Project », 2005-2008) avaitpour principaux objectifs d’évaluer la précision des méthodes numériques pour simuler la réponse sismique 2D/3D debassins sédimentaires, en comparant de manière quantitative, les réponses enregistrées et calculées. Dans ce cadre, il a étéchoisi d’utiliser le site EUROSEISTEST situé dans le bassin Mygdonien de la région de Volvi, proche de Thessalonique(Grèce). Dans cet article, nous présentons les résultats obtenus pour le cas linéaire 2D, avec 3 méthodes numériques :différences finies, éléments finis et éléments spectraux. Nous comparons également les résultats 2D avec les résultatslinéaires et non linéaires 1D obtenus sur 2 colonnes de sol extraites en bord et milieu du profil 2