21 research outputs found
Remote Laboratory for E-Learning of Systems on Chip and Their Applications to Nuclear and Scientific Instrumentation
Configuring and setting up a remote access laboratory for an advanced online school on fully programmable System-on-Chip (SoC) proved to be an outstanding challenge. The school, jointly organized by the International Centre for Theoretical Physics (ICTP) and the International Atomic Energy Agency (IAEA), focused on SoC and its applications to nuclear and scientific instrumentation and was mainly addressed to physicists, computer scientists and engineers from developing countries. The use of e-learning tools, which some of them adopted and others developed, allowed the school participants to directly access both integrated development environment software and programmable SoC platforms. This facilitated the follow-up of all proposed exercises and the final project. During the four weeks of the training activity, we faced and overcame different technology and communication challenges, whose solutions we describe in detail together with dedicated tools and design methodology. We finally present a summary of the gained experience and an assessment of the results we achieved, addressed to those who foresee to organize similar initiatives using e-learning for advanced training with remote access to SoC platforms
A scalable High Voltage Power Supply System with system on chip control for Micro Pattern Gaseous Detectors
The requirements posed to high voltage power supply systems by the operation of Micro Pattern Gaseous Detectors are specific in terms of high resolution diagnostic features and intelligent dynamic voltage control. These requirements are needed both when technology development is performed and when extended detector systems are supplied and monitored. Systems satisfying all the needed features are not commercially available.
A single channel high voltage system matching the Micro Pattern Gaseous Detector needs has been designed and realized, including its hardware and software components. The system employs a commercial DCDC converter and is coupled to a custom high resolution ammeter. Local intelligence, flexibility and high speed inter-connectivity are provided by a System on Chip Board and the use of a powerful FPGA. The single channel system has been developed, as critical milestone towards the realization of a multi-channel system.
The design, implementation and performance of the system are reported in detail in this article, as well as the performance of the single channel power supply when connected to a Micro Pattern Gaseous Detector in realistic working condition during a test beam exercise
Long term experience with perfluorobutane in COMPASS RICH
COMPASS RICH-1 has used high-purity perfluorobutane as radiator gas since
2001. The operation and control of the radiator gas has evolved over years with
continuous improvements. We report on the experience gained in the 20 year-long
operation of perfluorobutane as COMPASS RICH radiator. Very accurate values for
the radiator gas refractive index are needed for high-performance particle
identification. The procedure has evolved over years and the one presently in
use, which provides refractive index estimate at the 1 ppm level, is discussed.
Perfluorobutane procurement is becoming challenging, and the minimization of
material waste is now a priority for the protection of the environment.
Commercially available perfluorobutane needs dedicated filtering before usage
and typical material losses in the filtering procedure were around 30%. Recent
efforts allowed us to reduce them to about 5%. A potential alternative to
fluorocarbon radiators in gaseous RICHes is also presented.Comment: 4 pages, 3 figures 2 table
Spin Density Matrix Elements in Exclusive Meson Muoproduction
We report on a measurement of Spin Density Matrix Elements (SDMEs) in hard
exclusive meson muoproduction at COMPASS using 160~GeV/ polarised
and beams impinging on a liquid hydrogen target. The
measurement covers the kinematic range 5.0~GeV/ 17.0~GeV/,
1.0 (GeV/) 10.0 (GeV/) and 0.01 (GeV/) 0.5 (GeV/). Here, denotes the mass of the final
hadronic system, the virtuality of the exchanged photon, and
the transverse momentum of the meson with respect to the
virtual-photon direction. The measured non-zero SDMEs for the transitions of
transversely polarised virtual photons to longitudinally polarised vector
mesons () indicate a violation of -channel helicity
conservation. Additionally, we observe a dominant contribution of
natural-parity-exchange transitions and a very small contribution of
unnatural-parity-exchange transitions, which is compatible with zero within
experimental uncertainties. The results provide important input for modelling
Generalised Parton Distributions (GPDs). In particular, they may allow one to
evaluate in a model-dependent way the role of parton helicity-flip GPDs in
exclusive production
Collins and Sivers transverse-spin asymmetries in inclusive muoproduction of mesons
The production of vector mesons in deep inelastic scattering is an
interesting yet scarsely explored channel to study the transverse spin
structure of the nucleon and the related phenomena. The COMPASS collaboration
has performed the first measurement of the Collins and Sivers asymmetries for
inclusively produced mesons. The analysis is based on the data set
collected in deep inelastic scattering in using a
beam impinging on a transversely polarized target. The
mesons are selected from oppositely charged hadron pairs, and the
asymmetries are extracted as a function of the Bjorken- variable, the
transverse momentum of the pair and the fraction of the energy carried by
the pair. Indications for positive Collins and Sivers asymmetries are observed
Double production in pion-nucleon scattering at COMPASS
We present the study of the production of double mesons using
COMPASS data collected with a 190 GeV/ beam scattering off NH,
Al and W targets. Kinematic distributions of the collected double
events are analysed, and the double production cross section is
estimated for each of the COMPASS targets. The results are compared to
predictions from single- and double-parton scattering models as well as the
pion intrinsic charm and the tetraquark exotic resonance hypotheses. It is
demonstrated that the single parton scattering production mechanism gives the
dominant contribution that is sufficient to describe the data. An upper limit
on the double intrinsic charm content of pion is evaluated. No significant
signatures that could be associated with exotic tetraquarks are found in the
double mass spectrum.Comment: 12 pages, 4 figure
DAQ platform based on SoC-FPGA for high resolution time stamping in cosmic ray detection
Accurate timing in cosmic ray detection is critical for reconstruction of events from multiple scattered detectors. Since most of the detectors dedicated to study cosmic rays generate continuous analog signals, a precise timing depends on the sampling rate and the subsequent triggering system operating on the generated digital data stream. In this paper, a data acquisition platform based on a fully programmable System-On-Chip (SoC) and a high-speed analog to digital converter, able to manage 8-bit data resolution, 500MHz sampling rate and GPS connection for data synchronization is presented. The SoC is a ZYNQ 7000 device with a Field Programmable Gate Array (FPGA) and a dual core ARM processor embedded on a single chip. The system achieves 2 ns time resolution and is also able to increase data amplitude resolution through oversampling and can simultaneously generate a real time histogram of the incoming data. The platform has an embedded high voltage power supply control with temperature and pressure compensation for optimal and stable operation of different detectors. While the time critical activities are handled and carried out by the FPGA, software running on the dual core ARM processor with a real time operating system (FreeRTOS) provides Ethernet connection for remote control of the platform
The high voltage system of the novel MPGD-based photon detectors of COMPASS RICH-1 and its development towards a scalable High Voltage Power Supply System for MPGDs
The COMPASS RICH-1 detector has undergone a major upgrade in 2016 with the installation of four novel MPGD-based photon detectors. They consist of large-size hybrid MPGDs with multi-layer architecture composed of two layers of Thick-GEMs and bulk resistive MicroMegas. A dedicated high voltage power supply system, based on CAEN HV modules, has been built and put in operation: it controls more than 100 HV channels. The system is required to protect the detectors against errors by the operator, monitor voltages and currents at a 1 Hz rate and automatically react to detector misbehavior. It includes also a HV compensation system against environmental pressure and temperature variation to grant the detector stability. The operation of a MPGD based single photon detector poses challenging requirements to the high voltage power supply systems employed in terms of high-resolution diagnostic features and dynamic voltage control. Systems satisfying all the needed features are not commercially available; for this reason a novel single channel high voltage system matching the MPGD needs has been designed and realized. In this article the COMPASS RICH-1 MPGD HV system implementation is described as well as its performance in terms of stability of the novel MPGD-based photon detectors during the physics data taking at COMPASS. The design, implementation and performance of a novel HV power supply system based on DC to DC converters and controlled by a FPGA device is presented. The capabilities of the first prototype of the new single HV channel power supply are illustrated when operated with a MPGD based single photon detector during a test beam exercise. The preliminary result of the multi channel system are briefly discussed