A Full Front End Chain for Drift Chambers

We developed a high performance full chain for drift chamber signals processing. The Front End electronics is a multistage amplifier board based on high performance commercial devices. In addition a fast readout algorithm for Cluster Counting and Timing purposes has been implemented on a Xilinx-Virtex 4 core FPGA. The algorithm analyzes and stores data coming from a Helium based drift tube and represents the outcome of balancing between efficiency and high speed performance

Application of the Cluster Counting/Timing techniques to improve the performances of high transparency Drift Chamber for modern HEP experiments

Ultra-low mass and high granularity Drift Chambers seems to be a better choice for modern HEP experiments, to achieve a good momentum resolution on the charged particle. We present how, in Helium based gas mixture, by counting and measuring the arrival time of each individual ionization cluster and by using statistical tools, it is possible to reconstruct a bias free estimate of the impact parameter and a more discriminant Particle Identification

The construction technique of the high granularity and high transparency drift chamber of MEG II

The MEG experiment searches for the charged lepton flavor violating decay, μ +→ e+γ. MEG has already determined the world best upper limit on the branching ratio BR<4.2× 10−13 at 90% CL. An upgrade of the whole detector has been approved to obtain a substantial increase in sensitivity. Currently MEG is in upgrade phases, this phase involves all the detectors. The new positron tracker is a single volume, full stereo, small cells drift chamber (DCH) co-axial to the beam line. It is composed of 10 concentric layers and each single drift cell is approximately square 7 mm side, with a 20 μ m gold plated W sense wire surrounded by 40 μ m and 50 μ m silver plated Al field wires in a ratio of 5:1, about 12,000 wires. Due to the high wire density (12 wires/cm2), the use of the classical feed-through technique as wire anchoring system could hardly be implemented and therefore it was necessary to develop new wiring strategies. The number of wires and the stringent requirements on the precision of their position and on the uniformity of the wire mechanical tension impose the use of an automatic system to operate the wiring procedures. This wiring robot, designed and built at the INFN Lecce and University of Salento laboratories, consists of: ⋅ a semiautomatic wiring machine with a high precision on wire mechanical tensioning (better than 0.5 g) and on wire positioning (20 μ m) for simultaneous wiring of multiwire layers; ⋅ a contact-less infrared laser soldering tool; ⋅ an automatic handling system for storing and transporting the multi-wire layers. The drift chamber is currently under construction at INFN and should be completed by the end of summer 2017 to be then delivered to PSI for commissioning

The CluTim algorithm: an improvement on the impact parameter estimates

A Drift Chamber is a detector used in high energy physics experiments for determining charged particles trajectories. The signal pulses from all the wires are then collected and the particle trajectory is tracked assuming that the distances of closest approach (the impact parameter) between the particle trajectory and the wires coincide with the distance between the cluster ions generated by the particle and the wire closer to it. The widespread use of helium based gas mixtures, which produces a low ionization clusters density (12 cluster/cm in a 90/10 helium/iso-butane mixture), introduces a sensible bias in the impact parameter assumption, particularly for short impact parameters and small cell drift chambers. Recently, an alternative track reconstruction (Cluster Counting/Timing) technique has been proposed, which consists in measuring the arrival times on the wires of each individual ionization cluster and combining these times to get a bias free estimate of the impact parameter. However, in order to efficiently exploiting the cluster timing technique, it is necessary to have read-out interfaces capable of processing a large quantity of high speed signals. We describe the design of a read-out board capable of acquiring the information coming from a fast digitization of the signals generated in a drift chamber and the algorithm for identifying the individual ionization pulse peaks and recording their time and amplitude

ATLAS RPC QA results at INFN Lecce

The main results of the quality assurance tests performed on the Resistive Plate Chamber used by the ATLAS experiment at LHC as muon trigger chambers are reported and discussed. These are dark current, gas volume tomography, gas tightness, efficiency, and noise rate

The search for \ub5+ \u2192 e+\u3b3 with 10 1214 sensitivity: The upgrade of the meg experiment

The MEG experiment took data at the Paul Scherrer Institute in the years 2009\u20132013 to test the violation of the lepton flavor conservation law, which originates from an accidental symmetry that the Standard Model of elementary particle physics has, and published the most stringent limit on the charged lepton flavor violating decay \ub5+ \u2192 e+\u3b3: BR(\ub5+ \u2192 e+\u3b3) &lt; 4.2 7 10 1213 at 90% confidence level. The MEG detector has been upgraded in order to reach a sensitivity of 6 7 10 1214 . The basic principle of MEG II is to achieve the highest possible sensitivity using the full muon beam intensity at the Paul Scherrer Institute (7 7 107 muons/s) with an upgraded detector. The main improvements are better rate capability of all sub-detectors and improved resolutions while keeping the same detector concept. In this paper, we present the current status of the preparation, integration and commissioning of the MEG II detector in the recent engineering runs

Pseudorapidity densities of charged particles with transverse momentum thresholds in pp collisions at √ s = 5.02 and 13 TeV

The pseudorapidity density of charged particles with minimum transverse momentum (pT) thresholds of 0.15, 0.5, 1, and 2 GeV/c is measured in pp collisions at the center of mass energies of √s=5.02 and 13 TeV with the ALICE detector. The study is carried out for inelastic collisions with at least one primary charged particle having a pseudorapidity (η) within 0.8pT larger than the corresponding threshold. In addition, measurements without pT-thresholds are performed for inelastic and nonsingle-diffractive events as well as for inelastic events with at least one charged particle having |η|2GeV/c), highlighting the importance of such measurements for tuning event generators. The new measurements agree within uncertainties with results from the ATLAS and CMS experiments obtained at √s=13TeV.