Wafer test of the LHCb Outer Tracker TDC-Chip

The OTIS-TDC is the front end readout chip for the LHCb Outer Tracker. It is designed to measure drift times with a resolution better than 1 ns. As the chip will be directly mounted to its board, the test have to be performed on the wafer itself. As the testing period for 7 000 chips was only three weeks, many test routines have been implemented on a FPGA. Each chip is subjected to detailed probe testing to ensure the full functionality as well as a good performance. Overall 47 wafer have been tested. From the chips passing the test 2 000 have been used in the Outer Tracker front end electronic

Investigation of the Lightest Hybrid Meson Candidate with a Coupled-Channel Analysis of pˉp\bar{p}p-, π−p\pi^- p- and ππ\pi\pi-Data

Based on new insights from two recent coupled-channel analyses of $\bar{p}p$ annihilation together with $\pi\pi$-scattering data and of $\pi^- p$ data, this paper aims at a better understanding of the spin-exotic $\pi_1$ resonances in the light meson sector. The Crystal Barrel Collaboration observed the $\pi_1$-wave in $\bar{p}p$ annihilations in flight for the first time with the coupling to $\pi^0\eta$ in the reaction $\bar{p}p\,\rightarrow\,\pi^0\pi^0\eta$ with a sophisticated coupled-channel approach. Another refined coupled-channel analysis of the P- and D-waves in the $\pi\eta$ and $\pi\eta^\prime$ system based on data measured at COMPASS has been performed by the JPAC group. In that study the two spin-exotic signatures listed in the PDG, the $\pi_1(1400)$ and $\pi_1(1600)$, with a separate coupling to $\pi\eta$ and $\pi\eta^\prime$ can be described by a single pole. In this paper, both analyses, the one with the three $\bar{p}p$ annihilation channels into $\pi^0\pi^0\eta$, $\pi^0\eta\eta$ and $K^+K^-\pi^0$ and 11 different $\pi\pi$-scattering data sets and the one with the P- and D-wave data in the $\pi\eta$ and $\pi\eta^\prime$ systems measured at COMPASS, are subjected to a combined coupled channel analysis. By utilizing the K-matrix approach and realizing the analyticity via Chew-Mandelstam functions the $\pi_1$ wave can be well described by a single pole for both systems, $\pi\eta$ and $\pi\eta^\prime$. The mass and width of the $\pi_1$-pole are measured to be (1561.6 \, \pm \, 3.0 \, ^{+6.6}_{-2.6}\,)\, \mathrm{MeV/c}^2 and (388.1 \, \pm \, 5.4 \, ^{+0.2}_{-14.1}\,)\, \mathrm{MeV}.Comment: 5 pages, 2 figures, 1 tabl

The LHCb Outer Tracker Front End Electronics

This note provides an overview of the front-end electronics used to readout the drift-times of the LHCb Outer Tracker straw tube chambers. The main functional components of the readout are the ASDBLR ASIC for amplification and signal digitization, the OTIS ASIC for the time measurement and for the L0 buffering, and the GOL ASIC to serialize the digital data for the optical data transmission. The L1 buffer board used to receive the data which is sent via the optical link is a common LHCb development and is not described here. This note supersedes an earlier document [1]

MuPix7 - A fast monolithic HV-CMOS pixel chip for Mu3e

The MuPix7 chip is a monolithic HV-CMOS pixel chip, thinned down to 50 \mu m. It provides continuous self-triggered, non-shuttered readout at rates up to 30 Mhits/chip of 3x3 mm^2 active area and a pixel size of 103x80 \mu m^2. The hit efficiency depends on the chosen working point. Settings with a power consumption of 300 mW/cm^2 allow for a hit efficiency >99.5%. A time resolution of 14.2 ns (Gaussian sigma) is achieved. Latest results from 2016 test beam campaigns are shown.Comment: Proceedingsfor the PIXEL2016 conference, submitted to JINST A dangling reference has been removed from this version, no other change

On the behavior of micro-spheres in a hydrogen pellet target

A pellet target produces micro-spheres of different materials, which are used as an internal target for nuclear and particle physics studies. We will describe the pellet hydrogen behavior by means of fluid dynamics and thermodynamics. In particular one aim is to theoretically understand the cooling effect in order to find an effective method to optimize the working conditions of a pellet target. During the droplet formation the evaporative cooling is best described by a multi-droplet diffusion-controlled model, while in vacuum, the evaporation follows the (revised) Hertz-Knudsen formula. Experimental observations compared with calculations clearly indicated the presence of supercooling, the effect of which is discussed as well.Comment: 22 pages, 8 figures (of which two are significantly compressed for easier download