MHSP in reversed-biased operation mode for ion blocking in gas-avalanche multipliers

We present recent results on the operation of gas-avalanche detectors comprising a cascade of gas electron multipliers (GEMs) and Micro-Hole and Strip Plates (MHSPs) multiplier operated in reversed-bias (R-MHSP) mode. The operation mechanism of the R-MHSP is explained and its potential contribution to ion-backflow (IBF) reduction is demonstrated. IBF values of 4E-3 were obtained in cascaded R-MHSP and GEM multipliers at gains of about 1E+4, though at the expense of reduced effective gain in the first R- MHSP multiplier in the cascade.Comment: 23 pages, 8 figure

Digital signal processors in the LHCb level-1 vertex trigger system

99-002 The note discusses the use of Analog Devices' SHARC Digital Signal Processors for the Level-1 Vertex Trigger system implementation. It presents a short overview of current and future Analog Devices' floating-point DSP architectures, multiprocessor system architectures and a survey of available standard DSP board-level components and software for multiprocessor applications. A possible solution for mapping the vertex trigger algorithm on the scaleable DSP multiprocessor is discussed with analysis of its implementation using standard DSP multiprocessor components