The
NOE Collaboration has proposed a transition radiation detector (TRD) interleaved with marble targets to tag the electron decay channel of τ leptons produced by ν
τ, eventually originated by ν
μ ...oscillations in a long base line experiment. A reduced scale TRD detector prototype has been built and exposed to an electron/pion beam at the CERN PS. Discrimination capabilities between electrons and both charged and neutral pions, representing the main source of background for our measurement, have been determined obtaining rejection factors of the order of the tenth of percent for charged pions, and of a few percent for the neutral pion, matching the experiment requirements. The capabilities of this detector to measure the energy released by particles that start showering inside the targets are shown. A momentum resolution
σ
p
/
p≤40% is found for muons in the range of 1–
7
GeV/c
.
The NOE Collaboration has proposed a calorimeter to measure the energy of the final states of
ν interaction events. The properties of long scintillator bars with wavelength-shifting fiber readout ...have been studied to develop a calorimeter design option. Various prototypes have been exposed to a cosmic rays stand.
The total measured light yield in the middle of a
6
m
-long fiber is about 15 photoelectrons. With this photon collection performance, it has been simulated that the calorimeter can achieve
17%/
E
and
50%/
E
resolutions for electrons and pions, respectively.
Early warning for VHE gamma-ray flares with the ARGO-YBJ detector Bartoli, B.; Bernardini, P.; Bi, X.J. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2011, Volume:
659, Issue:
1
Journal Article
Peer reviewed
Open access
Detecting and monitoring emissions from flaring gamma-ray sources in the very-high-energy (VHE, > 100GeV) band is a very important topic in gamma-ray astronomy. The ARGO-YBJ detector is characterized ...by a high duty cycle and a wide field of view. Therefore, it is particularly capable of detecting flares from extragalactic objects. Based on fast reconstruction and analysis, real-time monitoring of 33 selected VHE extragalactic sources is implemented. Flares exceeding a specific threshold are reported timely, hence enabling the follow-up observation of these objects using more sensitive detectors, such as Cherenkov telescopes.
Gaseous and particulate pollutant concentrations associated with five samples per day collected during a July 2001 summer intensive study at the Pittsburgh Carnegie Mellon University (CMU) Supersite ...were used to apportion fine particulate matter (PM2.5) into primary and secondary contributions using PMF2. Input to the PMF2 analysis included the concentrations of PM2.5 nonvolatile and semivolatile organic material, elemental carbon (EC), ammonium sulfate, trace element components, gas-phase organic material, and NO(x), NO2, and O3 concentrations. A total of 10 factors were identified. These factors are associated with emissions from various sources and facilities including crustal material, gasoline combustion, diesel combustion, and three nearby sources high in trace metals. In addition, four secondary sources were identified, three of which were associated with secondary products of local emissions and were dominated by organic material and one of which was dominated by secondary ammonium sulfate transported to the CMU site from the west and southwest. The three largest contributors to PM2.5 were secondary transported material (dominated by ammonium sulfate) from the west and southwest (49%), secondary material formed during midday photochemical processes (24%), and gasoline combustion emissions (11%). The other seven sources accounted for the remaining 16% of the PM2.5. Results obtained at the CMU site were comparable to results previously reported at the National Energy Technology Laboratory (NETL), located approximately 18 km south of downtown Pittsburgh. The major contributor at both sites was material transported from the west and southwest. Some difference in nearby sources could be attributed to meteorology as evaluated by HYSPLIT model back-trajectory calculations. These findings are consistent with the majority of the secondary ammonium sulfate in the Pittsburgh area being the result of contributions from distant transport, and thus decoupled from local activity involving organic pollutants in the metropolitan area. In contrast, the major local secondary sources were dominated by organic material.
Large extensive air shower (EAS) arrays provide complementary technology for observation of very high-energy gamma rays. Whereas their instantaneous sensitivity is currently a factor ∼ 150 less than ...that of imaging atmospheric Cherenkov telescopes (IACTs), their large field of view (∼ 90 deg; 1.8 sr) and nearly 100% duty cycle makes these observatories particularly suited to conduct all-sky surveys and to detect emission from extended astrophysical sources. Due to the wide field of view coverage of the sky and uninterrupted operation, the EAS technique has also the potential to detect of very high energy (VHE) transient phenomena.
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