Evidence for πK-atoms with DIRAC Adeva, B.; Afanasyev, L.; Allkofer, Y. ...
Physics letters. B,
04/2009, Letnik:
674, Številka:
1
Journal Article
Recenzirano
Odprti dostop
We present evidence for the first observation of electromagnetically bound π±K∓-pairs (πK-atoms) with the DIRAC experiment at the CERN-PS. The πK-atoms are produced by the 24 GeV/c proton beam in a ...thin Pt-target and the π± and K∓-mesons from the atom dissociation are analyzed in a two-arm magnetic spectrometer. The observed enhancement at low relative momentum corresponds to the production of 173±54πK-atoms. The mean life of πK-atoms is related to the s-wave πK-scattering lengths, the measurement of which is the goal of the experiment. From these first data we derive a lower limit for the mean life of 0.8 fs at 90% confidence level.
A pair of new hodoscopes made of
0.28
mm
Ø
scintillating fibre have been built and tested at T11 beam line of CERN PS. They consist of seven layers of fibres, and are read out using multi-anode ...photomultipliers. The average number of photoelectrons produced by a minimum ionizing particle is found to be about 11, which resulted in a very high detection efficiency (98.6%) at an appropriate threshold setting. The hit multiplicity for single-hit events was suppressed to 1.12 at this threshold setting, thanks to the Peak-Sensing Circuit used for the readout. A spatial resolution of
∼
75
μ
m
and a time resolution of
∼
0.56
ns
(both in RMS) have been obtained with these hodoscopes. Further detailed study of the detector response such as double hit efficiency at very close distances, dependence on the incident angles has been performed.
Fundamental properties of YAP Imager Gorin, A; Kuroda, K; Manuilov, I ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2003, Letnik:
510, Številka:
1
Journal Article
Recenzirano
Two-dimensional pixel detector, called “YAP Imager”, was designed for SPring-8 high flux synchrotron radiation facilities in high energy X-ray or γ-ray region. It is based on YAlO
3:Ce crystals (YAP) ...with wavelength shifting fibers readout. The sensitive area of the imager is 132×132
mm
2 and it is composed of an array of 1×1×6
mm
3 YAP pillars. To supply two-dimensional readout two fiber layers (Kuraray B1(4
0
0)) with 128 fiber each are fixed at the top and bottom of the crystal array in orthogonal directions and optically connected with 8+8 H6568 (Hamamatsu) 16-anodes PMs. The obtained performances of the YAP Imager allow one to get a reliable imaging digital device without geometrical distortions with a spatial resolution close to 1
mm and ∼30% detection efficiency in 100
keV energy range.
An extensive study was performed on the development of fast and precise scintillating-fibre detectors with position-sensitive photomultipliers (PSPM) for application in high-rate experiments. Several ...detector prototypes with Kuraray multi-cladding fibres of
0.5
mm
diameter and Hamamatsu 16-channel H6568 PSPMs were constructed and tested under different beam conditions at the CERN PS and SPS beam lines. High time resolution of the order of
300
ps
(r.m.s.) was obtained with spatial resolution of about
125
μm
(r.m.s.) and with detection efficiency in excess of 98%. The detector prototype equipped with a 3-m-long light guide was also tested and showed a time resolution of about
540
ps
(r.m.s.). Results of tests using a high-intensity muon beam show excellent stability of the detector performances in time and spatial resolutions as well as in detection efficiency under beam fluxes of up to 1.4×10
8 muons per 2.4-second spill.
Peak-sensing discriminator for multichannel detectors with cross-talk Gorin, A; Kuznetsov, A; Manuilov, I ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2000, Letnik:
452, Številka:
1
Journal Article
Recenzirano
In view of handling the anode signals from the position-sensitive photomultiplier a new front-end electronic circuit has been designed and realized, which allows one to suppress annoying effects of ...the cross-talk between adjacent channels. The circuit was tested in association with a scintillating fibre detector in a test beam at CERN. The basic performances, such as the detection efficiency and its uniformity, as well as the hit multiplicity for single tracks were compared to those of the conventional electronics based on the simple threshold discriminators. A great advantage of the peak-sensing circuit was experimentally demonstrated, in particular, in its real-time digitization of the track position without significant ambiguity of the track position due to the cross-talk.
We are developing a fiber type two-dimentional (2-D) position-sensitive detector having a spatial resolution less than 0.5 mm in order to use it in the time-of-flight (TOF) measurements. The detector ...performance was examined, and some experiments on the TOF radiography were performed using this detector. The results indicated that the detector could be applied successfully to the TOF measurement and that the TOF radiography was very useful since it gave more informative data than those obtained by the conventional radiography using a broad energy band.
The multilevel trigger system of the DIRAC experiment Afanasyev, L.; Gallas, M.; Goldin, D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2002, Letnik:
491, Številka:
3
Journal Article
Recenzirano
Odprti dostop
The multilevel trigger system of the DIRAC experiment at CERN is presented. It includes a fast first level trigger as well as various trigger processors to select events with a pair of pions having a ...low relative momentum typical of the physical process under study. One of these processors employs the drift chamber data, another one is based on a neural network algorithm and the others use various hit-map detector correlations. Two versions of the trigger system used at different stages of the experiment are described. The complete system reduces the event rate by a factor of 1000 with respect to detectors’ single rates, the detection efficiency of events in the relative momentum range of interest being ⩾95%.
We applied a scintillator‐based area detector to the neutron time‐of‐flight method by developing a new electronics system for this detector, which detector consists of a thin plate of ZnS(Ag)+6Li ...scintillator optically coupled to wavelength shifter. The spatial resolution was about 0.4mm which is consistent with a fiber width of 0.4 mm. The detection efficiency for thermal neutrons was about 6%. A good‐resolution radiographic‐image as a function of flight time was obtained.
A fast and precise scintillating fiber (SciFi) tracker, using 0.5-mm-diameter fibers (Kuraray SCSF-78MJ) and position-sensitive photomultiplier tubes (Hamamatsu H6568), has been developed for the ...COMPASS (NA58) experiment at CERN. Tests of a 16-channel prototype showed an excellent stability in time resolution, in spatial resolution, as well as in detection efficiency under different beam flux of up to 1.4 /spl times/ 10/sup 8/ muons/spill. Four SciFi tracker stations have been constructed and all of them are presently under operation in the experiment with high performances as expected from the prototype.
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