First measurements of the Collins and Sivers asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarized 6LiD target are presented. The data were taken ...in 2002 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160 GeV/c. The Collins asymmetry turns out to be compatible with zero, as does the measured Sivers asymmetry within the present statistical errors.
COMPASS RICH-1 Albrecht, E.; Baum, G.; Birsa, R. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2003, Letnik:
502, Številka:
1
Journal Article
Recenzirano
RICH-1 is a large acceptance gaseous RICH using 3m of C4F10 as radiator and MWPCs with CsI photo-cathodes as VUV photon detectors. The main characteristics of this RICH are the large acceptance and ...the use of far UV photon detectors, which implies large dimensions, UV transparencies of the elements up to the photo-cathode, and good UV mirror reflectance.
We give a description of the detector, first results about its performances and a report about various technological achievements required by this challenging project.
The radiator gas and the gas system of COMPASS RICH-1 Albrecht, E.; Baum, G.; Bellunato, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2003, Letnik:
502, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The design of the COMPASS RICH-1 gas system, its operational modes, the cleaning setups for the preparation of the radiator gas and transmission measurement installations are described. The gas ...system in presently fully operational and satisfactory transmission of VUV light through the radiator gas has been reached.
The mirror system of COMPASS RICH-1 Albrecht, E.; Baum, G.; Birsa, R. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2003, Letnik:
502, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The architecture and the properties of the mirror system of the COMPASS RICH-1 detector, composed by 116 spherical VUV reflecting units supported by a lightweight mechanical structure, are described.
This paper presents technical details, hardware and software of a complete imaging system which uses a fast CCD sensor and a 41 Msample/s A/D converter to acquire full-frame 12 bit/pixel digitized ...images with a time resolution of 1.25 ms/image. This apparatus permits to resolve intracellular Ca2+gradients in individual cells as well as the spatio-temporal pattern of neural activity of cell assemblies in neural tissue.
We study the demixing tendencies observed in some Sn-based liquid alloys, specifically, Ga–Sn, Al–Sn and Fe–Sn liquid alloys using a phenomenological model. With the aid of the model, we investigate ...the concentration dependence of thermodynamic properties viz: activity, free energy of mixing, enthalpy of mixing, entropy of mixing and the chemical diffusion. The parameters that characterize the model, enable us to describe the energetics of the system in terms of the concentration–concentration fluctuations in the long wavelength limit. We deduce from our study that of the three liquid alloys, the thermodynamic properties of Fe–Sn are most asymmetric as a function of concentration, the observed asymmetry is explained on the basis of the size effect. From the results for Ga–Sn and Al–Sn, we infer that with increase in the atomic number of the element in group III that is added to liquid Sn, there is a reduced tendency for segregation. We deduce within the present framework that In–Sn would be a hetero-coordinated system. This deduction is in agreement with available experimental data.
The COMPASS RICH-1 read-out system Baum, G.; Birsa, R.; Bradamante, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2003, Letnik:
502, Številka:
1
Journal Article
Recenzirano
Odprti dostop
This paper describes the reconfigurable read-out system for the 82944 RICH-1 channels of the COMPASS experiment (NA58) at CERN. The system is based on 192 identical large front-end boards (BORA ...board). BORA was designed for acquiring, digitizing, threshold subtracting and transmitting event data. The overall operation of the board is controlled and supervised by a DSP tightly interacting with an FPGA that acts as a parallel co-processor. The DSP allows characterizing each analog channel by locally calculating noise and pedestal. Each BORA communicates with the outside world through two optical fibers and through a dedicated DSP network. One optical fiber is used to receive event triggers, and the other one is used to transmit event data to subsequent processing stages of the acquisition system. The DSP network allows reconfiguring and reprogramming the DSPs and FPGAs as well as acquiring sample events to visualize the overall operation of the system. The whole RICH has eight DSP networks working in parallel. These networks are handled by DOLINA, a PC resident multiprocessor board containing eight DSPs. Each network is formed by 24 BORA DSPs and 1 DOLINA DSP. The read-out system can steadily work up to a trigger rate of 75kHz with maximum pixel occupancy of 20%, reaching a transmission data rate of 5.13Gbytes/s.
RICHONE: a software package for the analysis of COMPASS RICH-1 data Baum, G.; Birsa, R.; Bradamante, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2003, Letnik:
502, Številka:
1
Journal Article
Recenzirano
Odprti dostop
RICHONE is the pattern recognition and PID code for COMPASS RICH-1. RICHONE is part of CORAL, the COMPASS software system, a C++ framework developed within the collaborations using up-to-date ...techniques and tools.
COMPASS RICH-1 Albrecht, E; Baum, G; Birsa, R ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2002, Letnik:
478, Številka:
1
Journal Article
Recenzirano
Odprti dostop
RICH-1 is one of the key detectors of the COMPASS experiment at CERN. It is a large acceptance gaseous RICH, designed to perform
π/
κ separation up to 60
GeV/
c. All RICH-1 components are built, most ...of them have been commissioned during year 2000 COMPASS technical run and the detector will be completed during Spring 2001. We give a description of the detector and report about various technological achievements required by this challenging project.
PDF
