Feasibility study to characterize the production of antineutrons in high energy pppp collisions through charge exchange interactions

Simulations to evaluate the feasibility of $\bar{n}$ identification and kinematic characterization via the hadronic charge exchange (CEX) interaction $n+\bar{n}\rightarrow p+\bar{p}$ are reported. The target neutrons are those composing the silicon nuclei of which inner tracking devices present in LHC experiments are made. Simulations of $pp$ collisions in PYTHIA were carried out at different energies to investigate $\bar{n}$ production and the expected $\bar{n}$ energy spectra. Then, two types of GEANT4 simulations were performed, placing an $\bar{n}$ point source at the ALICE primary vertex as a working example. In the first simulation, the $E_k$ was kept at an arbitrary (1 GeV) fix value to develop an $\bar{n}$ identification and kinematics reconstruction protocol. The second GEANT4 simulation used the resulting PYTHIA at $\sqrt{s_{pp}}=13$ TeV $\bar{n}$ energy spectra. In both simulations, the occurrence of CEX interactions was identified by the unique outgoing $\bar{p}$. The simplified simulation allowed to estimate a 0.11% CEX-interaction identification efficiency at $E_k = 1$ GeV. The $p$ CEX-partner identification is challenging because of the presence of silicon nucleus-fragmentation protons. Momentum correlations between the $\bar{n}$ and all possible $\bar{p}p$ pairs showed that $p$ CEX-partner identification and $\bar{n}$ kinematics reconstruction corresponds to minimal momentum-loss events. The use of ITS $dE/dx$ information is found to improve $\bar{n}$ identification and kinematic characterization in both simulations. The final protocol applied to the realistic simulation resulted in a $\bar{n}$ identification and kinematic reconstruction efficiency of 0.006%, based solely on $\bar{p}p$ pair observable. Thus, the expected rate of identified and kinematically reconstructed $\bar{n}$ should lie in the order of 100,000 per second, illustrating the feasibility of the method.Comment: 6 pages, 11 figure

Origin of the high energy proton component below the geomagnetic cutoff in near earth orbit

The high flux proton component observed by AMS below the geomagnetic cutoff can be well accounted for by assuming these particles to be secondaries originating from the interaction of Cosmic Ray protons with the atmosphere. Simulation results are reporte

SISTEMA DE MONITOREO PARA EL ESTUDIO HIDRODINÁMICO DE LA LAGUNA DEL CARPINTERO

Una de las características más importantes de los estuarios o lagunas, es la interacción entre el agua dulce y la de mar. La dinámica de estos es afectada por las mareas, el oleaje, el viento, la precipitación pluvial, la evaporación, los flujos de agua dulce y el transporte de sedimentos. El estudio de la hidrodinámica en estos ecosistemas es uno de los aspectos más importantes que se necesitan para crear  las bases necesarias para una correcta y debida planeación en diseño de obras de infraestructura turística y social. Por tal motivo en el presente trabajo se desarrollo un sistema de monitoreo con la finalidad de comenzar a generar una base de datos de gran importancia para poder realizar un estudio hidrodinámico de la Laguna del Carpintero, situada en el centro de la ciudad de Tampico. El sistema está compuesto por un mareógrafo ultrasónico que permite el monitoreo en tiempo real del nivel del agua con una exactitud de ±7mm y de su temperatura con una resolución de ±0.5ºC

The use of cosmic muons in detecting heterogeneities in large volumes

The muon intensity attenuation method to detect heterogeneities in large matter volumes is analyzed. Approximate analytical expressions to estimate the collection time and the signal to noise ratio, are proposed and validated by Monte Carlo simulations. Important parameters, including point spread function and coordinate reconstruction uncertainty are also estimated using Monte Carlo simulations.Comment: 8 pages, 11 figures, submetted to NIM

Proton and Helium Spectra from the CREAM-III Flight

Primary cosmic-ray elemental spectra have been measured with the balloon-borne Cosmic Ray Energetics And Mass (CREAM) experiment since 2004. The third CREAM payload (CREAM-III) flew for 29 days during the 2007-2008 Antarctic season. Energies of incident particles above 1 TeV are measured with a calorimeter. Individual elements are clearly separated with a charge resolution of ~0.12 e (in charge units) and ~0.14 e for protons and helium nuclei, respectively, using two layers of silicon charge detectors. The measured proton and helium energy spectra at the top of the atmosphere are harder than other existing measurements at a few tens of GeV. The relative abundance of protons to helium nuclei is 9.53+-0.03 for the range of 1 TeV/n to 63 TeV/n. The ratio is considerably smaller than other measurements at a few tens of GeV/n. The spectra become softer above ~20 TeV. However, our statistical uncertainties are large at these energies and more data are needed

Design and construction of a Cherenkov imager for charge measurement of nuclear cosmic rays

A proximity focusing Cherenkov imager called CHERCAM, has been built for the charge measurement of nuclear cosmic rays with the CREAM instrument. It consists of a silica aerogel radiator plane across from a detector plane equipped with 1,600 1" diameter photomultipliers. The two planes are separated by a ring expansion gap. The Cherenkov light yield is proportional to the charge squared of the incident particle. The expected relative light collection accuracy is in the few percents range. It leads to an expected single element separation over the range of nuclear charge Z of main interest 1 < Z < 26. CHERCAM is designed to fly with the CREAM balloon experiment. The design of the instrument and the implemented technical solutions allowing its safe operation in high altitude conditions (radiations, low pressure, cold) are presented.Comment: 24 pages, 19 figure

The AMS-02 RICH Imager Prototype - In-Beam Tests with 20 GeV/c per Nucleon Ions -

A prototype of the AMS Cherenkov imager (RICH) has been tested at CERN by means of a low intensity 20 GeV/c per nucleon ion beam obtained by fragmentation of a primary beam of Pb ions. Data have been collected with a single beam setting, over the range of nuclear charges 2<Z<~45 in various beam conditions and using different radiators. The charge Z and velocity beta resolutions have been measured.Comment: 4 pages, contribution to the ICRC 200

Towards the critical behavior for the light nuclei by NIMROD detector

The critical behavior for the light nuclei with A$\sim 36$ has been investigated experimentally by the NIMROD multi-detectors. The wide variety of observables indicate the critical point has been reached in the disassembly of hot nuclei at an excitation energy of 5.6$\pm$0.5 MeV/u.Comment: 4 pages, 2 figures; Proceeding of 18th Nuclear Physics Division Conference of the Euro. Phys. Society (NPDC18) "Phase transitions in strongly interacting matter", Prague, 23.8.-29.8. 2004. To be published in Nuclear Physics