Bias dependence and bistability of radiation defects in silicon

Influence of bias on effective dopant concentration in neutron and pion irradiated$p^+ - n - n^+$ diodes has been measured. Detailed studies of annealing of the bias-induced damagehave revealed three components, with introduction rates from 0.005 to 0.008 cm$^{-1}$ andannealing time constants ranging from 5 to 1000 hours at 20$^\circ$C. Variation of annealing temperatures yielded activation energies around 1 eV for all the three components. Bistable behavior of radiation damage under bias has been observed and its activation and annealingstudied. The bistable damage was associated to the fastest annealing component of bias-induced damage.Using the parameterization obtained, a prediction for ATLAS SCT operation was made.Bias-induced damage is shown to require an additional 80 V to fully deplete detectors at the end of LHC operation

Chain of refined perception in self-optimizing assembly of micro-optical systems

Today, the assembly of laser systems requires a large share of manual operations due to its complexity regarding the optimal alignment of optics. Although the feasibility of automated alignment of laser optics has been shown in research labs, the development effort for the automation of assembly does not meet economic requirements – especially for low-volume laser production. This paper presents a model-based and sensor-integrated assembly execution approach for flexible assembly cells consisting of a macro-positioner covering a large workspace and a compact micromanipulator with camera attached to the positioner. In order to make full use of available models from computer-aided design (CAD) and optical simulation, sensor systems at different levels of accuracy are used for matching perceived information with model data. This approach is named "chain of refined perception", and it allows for automated planning of complex assembly tasks along all major phases of assembly such as collision-free path planning, part feeding, and active and passive alignment. The focus of the paper is put on the in-process image-based metrology and information extraction used for identifying and calibrating local coordinate systems as well as the exploitation of that information for a part feeding process for micro-optics. Results will be presented regarding the processes of automated calibration of the robot camera as well as the local coordinate systems of part feeding area and robot base

Investigation of the negative influence of cooling lubricants on the deformation of the machine tool structure

Cooling lubricants have a significant influence on the thermal state of a machine tool. The fluid absorbs the thermal energy of the cutting process and dissipates it to prevent wear of the tool and distortion of the work piece. However, the unpredictable flow of the cooling lubricant also transfers the energy to the machine tool structure and can thus have a negative impact on the produced work piece quality. While the thermal behaviour of machine tools under the influence of thermal environmental conditions is already the subject of ongoing research projects, the influence of cooling lubricants on the thermal state of the machine tool and thus the achievable manufacturing accuracy is still largely unexplored. This paper investigates the thermally induced deformations of the machine tool structure, as well as the impact on the Tool Centre Point (TCP)

Recent progress of the ATLAS Planar Pixel Sensor R&D Project

The foreseen luminosity upgrade for the LHC (a factor of 5-10 more in peak luminosity by 2021) poses serious constraints on the technology for the ATLAS tracker in this High Luminosity era (HL-LHC). In fact, such luminosity increase leads to increased occupancy and radiation damage of the tracking detectors. To investigate the suitability of pixel sensors using the proven planar technology for the upgraded tracker, the ATLAS Planar Pixel Sensor R&D Project was established comprising 17 institutes and more than 80 scientists. Main areas of research are the performance of planar pixel sensors at highest fluences, the exploration of possibilities for cost reduction to enable the instrumentation of large areas, the achievement of slim or active edge designs to provide low geometric inefficiencies without the need for shingling of modules and the investigation of the operation of highly irradiated sensors at low thresholds to increase the efficiency. In the following I will present results from the group, concerning mainly irradiated-devices performance, together with studies for new sensors, including detailed simulations.Comment: 9 pages,12 figure

Improved Measurements of Partial Rate Asymmetry in B -> h h Decays

We report improved measurements of the partial rate asymmetry (Acp) in B -> h h decays with 140fb^-1 of data collected with the Belle detector at the KEKB e+e- collider. Here h stands for a charged or neutral pion or kaon and in total five decay modes are included: K-+ pi+-, K0s pi-+, K-+ pi0, pi-+ pi0 and K0s pi0. The flavor of the last decay mode is determined from the accompanying B meson. Using a data sample 4.7 times larger than that of our previous measurement, we find Acp(K-+ pi+-) -0.088+-0.035+-0.013, 2.4 sigma from zero. Results for other decay modes are also presented.Comment: 9 pages, 1 figur

Search for CP violation in the decay B0->D*+-D-+

We report a search for CP-violating asymmetry in B0 -> D*+- D-+ decays. The analysis employs two methods of B0 reconstruction: full and partial. In the full reconstruction method all daughter particles of the B0 are required to be detected; the partial reconstruction technique requires a fully reconstructed D- and only a slow pion from the D*+ -> D0 pi_slow+ decay. From a fit to the distribution of the time interval corresponding to the distance between two B meson decay points we calculate the CP-violating parameters and find the significance of nonzero CP asymmetry to be 2.7 standard deviations.Comment: 4 pages, 3 figure

Studies of the Decay B+- -> D_CP K+-

We report studies of the decay B+- -> D_CP K+-, where D_CP denotes neutral D mesons that decay to CP eigenstates. The analysis is based on a 29.1/fb data sample of collected at the \Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e+ e- storage ring. Ratios of branching fractions of Cabibbo-suppressed to Cabibbo-favored processes involving D_CP are determined to be B(B- -> D_1 K-)/B(B- -> D_1 pi-)=0.125 +- 0.036 +- 0.010 and B(B- -> D_2 K-)/B(B- -> D_2 pi-)=0.119 +- 0.028 +- 0.006, where indices 1 and 2 represent the CP=+1 and CP=-1 eigenstates of the D0 - anti D0 system, respectively. We also extract the partial rate asymmetries for B+- -> D_CP K+-, finding A_1 = 0.29 +- 0.26 +- 0.05 and A_2 = -0.22 +- 0.24 +- 0.04.Comment: 10 pages, 2 figures, submitted to Physical Review Letter

Measurements of the branching fraction and polarization in B+->rho K-+(*0) decays

We present the results of a study of the charmless vector-vector decay B+->rho K-+(*0), based on 253 fb(-1) of data collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We obtain the branching fraction B(B+->rho K-+(*0))=[8.9 +/- 1.7(stat)+/- 1.2(syst)]x10(-6). We also perform a helicity analysis of the rho and K-* vector mesons, and obtain the longitudinal polarization fraction f(L)(B+->rho K-+(*0))=0.43 +/- 0.11(stat)(-0.02)(+0.05)(syst)

Search for D-0-D-0(-) mixing in D-0 -> K+pi(-) decays and measurement of the doubly-Cabibbo-suppressed decay rate

We have searched for mixing in the Ddegrees-(D) over cap (0) D-0 system by measuring the decay-time distribution of D0 ! K(+)pi(-) decays. The analysis uses 90 fb(-1) of data collected by the Belle detector at the KEKB e(+) e(-) collider. We fit the decay-time distribution for the mixing parameters x(1) and y(1) and also for the parameter R-D, which is the ratio of the rate for the doubly-Cabibbo-suppressed decay D-0--> K(+)pi(-) to that for the Cabibbo-favored decay D-0 --> K- pi(+). We do these fits both assuming CP conservation and allowing for CP violation. We use a frequentist method to obtain a 95% C. L. region in the x(J2)- y(l) plane. Assuming no mixing, we measure R-D=(0: 381 +/- 0: 017 (+) (0.008)(-0.016))%

Observation of large CP violation and evidence for direct CP violation in B0+p- decays

We report the first observation of CP violation in B0+p- decays based on 152x106 U(4S)B (B) over bar decays collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. We reconstruct a B0+p- CP eigenstate and identify the flavor of the accompanying B meson from its decay products. From the distribution of the time intervals between the two B meson decay points, we obtain App=+0.580.15(stat)0.07(syst) and Spp=-1.000.21(stat)0.07(syst). We rule out the CP-conserving case, App=Spp=0, at a level of 5.2 standard deviations. We also find evidence for direct CP violation with a significance at or greater than 3.2 standard deviations for any Spp value