Data handling, reconstruction, and simulation for the KLOE experiment Ambrosino, F.; Antonelli, A.; Antonelli, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2004, Letnik:
534, Številka:
3
Journal Article
Recenzirano
Odprti dostop
The broad physics program of the KLOE experiment is based on the high event rate at the Frascati φ
factory, and calls for an up-to-date system for data acquisition and processing. In this review of ...the KLOE offline environment, the architecture of the data-processing system and the programs developed for data reconstruction and Monte Carlo simulation are described, as well as the various procedures used for data handling and transfer between the different components of the system.
The electromagnetic form factors of the neutron in the time-like region have been measured for the first time, from the threshold up to
q
2 ⋟ 6
GeV
2
. The neutron magnetic form factor turns out to ...be larger than the proton one; the angular distribution suggests that for the neutron, at variance with the proton case, electric and magnetic form factors could be different. Further measurements are also reported, concerning the proton form factors and the
Σ
Σ
production, together with the multihadronic cross section and the
J/
Γ branching ratio into
n
n
.
Process and Data Flow Control in KLOE Pasqualucci, E.
Computer physics communications,
10/2001, Letnik:
140, Številka:
1
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
The core of the KLOE distributed event building system is a switched network. The online processes are distributed over a large set of processors in this network. All processes have to change ...coherently their state of activity as a consequence of local or remote commands. A fast and reliable message system based on the SNMP protocol has been developed. A command server has been implemented as a non privileged daemon able to respond to “set” and “get” queries on private SNMP variables. This process is able to convert remote set operations into local commands and to map automatically an SNMP subtree on a user-defined set of process variables. Process activity can be continuously monitored by remotely accessing their variables by means of the command server. Only the command server is involved in these operations, without disturbing the process flow. Subevents coming from subdetectors are sent to different nodes of a computing farm for the last stage of event building. Based on features of the SNMP protocol and of the KLOE message system, the Data Flow Control System (DFC) is able to rapidly redirect network traffic, keeping in account the dynamics of the whole DAQ system in order to assure coherent subevent addressing in an asynchronous “push” architecture, without introducing dead time. The KLOE DFC is currently working in the KLOE DAQ system. Its main characteristics and performance are discussed.
The trigger system of the KLOE experiment Adinolfi, M; Ambrosino, F; Antonelli, M ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2002, Letnik:
492, Številka:
1
Journal Article
Recenzirano
Odprti dostop
We present the design of the trigger system for the KLOE experiment at the Frascati
φ-factory DAΦNE. The detector consists of a large-volume drift chamber and a calorimeter both immersed in a
0.52
T
...solenoidal field. The trigger, structured with a first- and a second-decision level, is based on the multiplicity of energy deposits in the calorimeter and of hits in the drift chamber. The selection criteria are described and the efficiency for detecting
φ decays is evaluated using data.
The nucleon form factors have been extensively studied in the space-like region by several experiments. In the time-like region, only recently some precise measurements of the proton form factor ...became available and only one measurement of the neutron one has been performed by FENICE. In this paper, the main FENICE results are described, including the measurement of neutron and proton form factors and of the total
e
+
e
− →
hadrons cross section close to the
e
+e
− → N
N
threshold.
The general behaviour of the neutron time-like form factors is rather unexpected. In the unphysical region, nucleon form factors have been studied by means of dispersion relations, using a model independent regularization method. No φ signal has been found, in contrast with some expectation about the strange quark content in the nucleon. However, large errors are present in these results, due to large errors in present data.
In general, more data are demanded in order to have a complete knowledge of the time-like form factors of the neutron, experically close to the threshold, where there are some indications for a steep behaviour. A new experiment is proposed at SLAC in order to measure the nucleon form factors in the time-like region with the same accuracy than we have in the space-like one, disentangling the electric and magnetic contribution to the cross section.
The ATLAS MDT remote calibration centers Dai, T; Salvo, A De; Diehl, E ...
Journal of physics. Conference series,
04/2010, Letnik:
219, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The precision chambers of the ATLAS Muon Spectrometer are built with Monitored Drift Tubes (MDT). The requirement of high accuracy and low systematic error, to achieve a transverse momentum ...resolution of 10% at 1 TeV, can only be accomplished if the calibrations are known with an accuracy of 20 μm. The relation between the drift path and the measured time (the socalled r-t relation) depends on many parameters (temperature T, hit rate, gas composition, thresholds,...) subject to time variations. The r-t relation has to be measured from the data without the use of an external detector, using the autocalibration technique. This method relies on an iterative procedure applied to the same data sample, starting from a preliminary set of constants. The required precision can be achieved using a large (few thousand) number of non-parallel tracks crossing a region, called calibration region, i.e. the region of the MDT chamber sharing the same r-t relation.
In the ATLAS experiment at the LHC, the ROD Crate DAQ provides a complete software framework to implement data acquisition functionality at the boundary between the detector specific electronics and ...the common part of the data acquisition system. Based on a plugin mechanism, it allows selecting and using common services (like data output and data monitoring channels) and developing software to control and acquire data from detector specific modules providing the infrastructure for control, monitoring and calibration. Including also event building functionality, the ROD Crate DAQ is intended to be the main data acquisition tool for the first phase of detector commissioning. This paper presents the design, functionality and performance of the ROD Crate DAQ and its usage in the ATLAS data acquisition system and during detector tests.
Test of the first BIL tracking chamber for the ATLAS muon spectrometer Avolio, G.; Bagnaia, P.; Baroncelli, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2004, Letnik:
523, Številka:
3
Journal Article
Recenzirano
The first Barrel Inner Large chamber of the Monitored Drift Tube (MDT) tracking detector for the muon spectrometer of the ATLAS experiment has been tested with a high-energy muon beam. After a ...description of the MDT characteristics, we present the test beam experimental set-up, the data analysis techniques and discuss the results. The chamber was operated with a Ar(93%)–CO
2(7%) gas mixture at 3-bar pressure. The performance studies include the chamber calibration, the single-tube resolution, efficiency and electronic noise, and their behaviour as a function of the high-voltage setting and discriminator threshold.
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