P. Cabanelas

Performance of the Low-Jitter High-Gain/Bandwidth Front-End Electronics of the HADES tRPC Wall

A front-end electronics (FEE) chain for accurate time measurements has been developed for the new Resistive Plate Chamber (RPC)-based Time-of-Flight (TOF) wall of the High Acceptance Di-Electron Spectrometer (HADES). The wall covers an area of around 8 m2, divided in 6 sectors. In total, 1122 4-gap timing RPC cells are read-out by 2244 time and charge sensitive channels. The FEE chain consists of 2 custom-made boards: a 4-channel DaughterBOard (DBO) and a 32-channel MotherBOard (MBO). The DBO uses a fast 2 GHz amplifier feeding a dual high-speed discriminator. The time and charge information are encoded, respectively, in the leading edge and the width of an LVDS signal. Each MBO houses up to 8 DBOs providing them regulated voltage supply, threshold values via DACs, test signals and, additionally, routing out a signal proportional to the channel multiplicity needed for a 1st level trigger decision. The MBO delivers LVDS signals to a multi-purpose Trigger Readout Board (TRB) for data acquisition. The FEE allows achieving a system resolution around 75 ps fulfilling comfortably the requirements of the HADES upgrade .

Analysis of the space-time microstructure of cosmic ray air showers using the HADES RPC TOF wall

Cosmic rays have been studied, since they were discovered one century ago, with a very broad spectrum of detectors and techniques. However, never the properties of the extended air showers (EAS) induced by high energy primary cosmic rays had been analysed at the Earth surface with a high granularity detector and a time resolution at the 0.1 ns scale. The commissioning of the timing RPC (Resistive Plate Chambers) time of flight wall of the HADES spectrometer with cosmic rays, at the GSI (Darmstadt, Germany), opened up that opportunity. During the last months of 2009, more than 500 millions of cosmic ray events were recorded by a stack of two RPC modules, of about 1.25 m2 each, able to measure swarms of up to ~ 100 particles with a time resolution better than 100 ps. In this document it is demonstrated how such a relative small two-plane, high-granularity timing RPC setup may provide significant information about the properties of the shower and hence about the primary cosmic ray properties.

Analysis of the front structure of EAS with the HADES tRPC wall

Alberto Blancoa, Daniel Belverb, Pablo Cabanelasb, Jose Diazc, Paulo Fontea,d , Juan A. Garzonb, Alejandro Gilc, Diego Gonzalez-Diaze, Wolfgang Koenig f , Georgy Kornakov∗a,b, Burkhard Kolb f , Luis Lopesa, Marek Palkag, Americo Pereiraa, Michael Traxler f , Peter Zumbruch f aLaboratorio de Instrumentacao e Fisica Experimental de Particulas, LIP, Coimbra, Portugal bLabCAF, Universidade de Santiago de Compostela, USC, Santiago de Compostela, Spain cInstituto de Fisica Corpuscular, IFIC, Valencia, Spain dISEC-Instituto Superior de Engenharia de Coimbra, Coimbra, Portugal eLaboratorio de Fisica Nuclear y Altas Energias, Universidad de Zaragoza, Zaragoza, Spain f GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt, Germany gSmoluchowski Institute of Physics, Jagiellonian University of Cracow, Poland

Inclusive e + e pair production in p+p and p+Nb collisions at E kin = 3:5 GeV

We report on recent data of e+e− pair emission in proton nucleus collisions at energies above the light vector meson production thresholds. Invariant mass distributions for the p+Nb system at Ekin = 3.5 GeV are compared to data from elementary p+p reactions at the same beam energy. We observe a constant π0/ω yield ratio for both systems but an excess in the mass region above the π0 mass. Furthermore we present here the normalization procedure that was applied to p+Nb collisions by measuring the production of negative pions in the HADES acceptance.

Control and Monitoring System for the HADES RPC detector

The Control and Monitoring System designed for the Front-End Electronics of the HADES RPC detector, installed at GSI Helmholtz Centre for Heavy Ion Research GmbH (Darmstadt, Germany), is described. This new detector for the Time-of-Flight detection system of HADES contains 1116 electrically shielded RPC cells and covers an active area of about 8m2. The slow control system controls/monitors about 6500 variables and is being implemented using the Experimental Physics and Industrial Control System (EPICS) Software tool kit. A MEDM graphical interface is being developed for the client system. The Control and Monitoring System attends four different systems: Front-End Electronics, Low Voltage System, Detector and Gas System. Each system communicates the control/monitoring system via a different and independent hardware interface, but the user interacts with a common software application that interfaces all systems. The Front-End Electronics has 2232 electronic channels that require threshold setting of the LTC2620 chips via Serial Peripheral Interface (SPI). The Low Voltage System monitors currents and voltages via 1-Wire bus. The detector is equipped with controllable switches and the Gas System requires the control and monitoring for the gas flows. Temperature of all systems is sensed using the DS18B20 chip. The Data Acquisition System interacts with the main part of the systems via system-on-chip ETRAX computers (equipped with Ethernet port) that run EPICS IO servers over an embedded LINUX kernel.

New RPC front-end electronics for hades

Time-of-flight (TOF) detectors are mainly used for both particle identification and triggering. Resistive Plate Chamber (RPC) detectors are becoming widely used because of their excellent TOF capabilities and reduced cost. The new ESTRELA RPC wall, which is being installed in the HADES detector at Darmstadt GSI, will contain 1024 RPC modules, covering an active area of around 7 m. It has excellent TOF and good charge resolutions. Its Front-End electronics is based on a 8-layer Mother-Board providing impedance matched paths for the output signals of each of the eight 4-channel Daughter-Boards to the TDC.