Development of a Momentum Determined Electron Beam in the 1 -45 GeV Range

A beam line for electrons with energies in the range of 1 to 45 GeV, low contamination of hadrons and muons and high intensity up to 10^6 per accelerator spill at 27 GeV was setup at U70 accelerator in Protvino, Russia. A beam tagging system based on drift chambers with 160 micron resolution was able to measure relative electron beam momentum precisely. The resolution sigma_p p was 0.13% at 45 GeV where multiple scattering is negligible. This test beam setup provided the possibility to study properties of lead tungstate crystals (PbWO_4) for the BTeV experiment at Fermilab.Comment: 12 pages, 8 figures; work done by the BTeV Electromagnetic Calorimeter grou

Correlation of Beam Electron and LED Signal Losses under Irradiation and Long-term Recovery of Lead Tungstate Crystals

Radiation damage in lead tungstate crystals reduces their transparency. The calibration that relates the amount of light detected in such crystals to incident energy of photons or electrons is of paramount importance to maintaining the energy resolution the detection system. We report on tests of lead tungstate crystals, read out by photomultiplier tubes, exposed to irradiation by monoenergetic electron or pion beams. The beam electrons themselves were used to measure the scintillation light output, and a blue light emitting diode (LED) was used to track variations of crystals transparency. We report on the correlation of the LED measurement with radiation damage by the beams and also show that it can accurately monitor the crystals recovery from such damage.Comment: 9 pages, 6 figures, LaTeX2

Comparison of Radiation Damage in Lead Tungstate Crystals under Pion and Gamma Irradiation

Studies of the radiation hardness of lead tungstate crystals produced by the Bogoroditsk Techno-Chemical Plant in Russia and the Shanghai Institute of Ceramics in China have been carried out at IHEP, Protvino. The crystals were irradiated by a 40-GeV pion beam. After full recovery, the same crystals were irradiated using a $^{137}Cs$ $\gamma$-ray source. The dose rate profiles along the crystal length were observed to be quite similar. We compare the effects of the two types of radiation on the crystals light output.Comment: 10 pages, 8 figures, Latex 2e, 28.04.04 - minor grammatical change

LED Monitoring System for the BTeV Lead Tungstate Crystal Calorimeter Prototype

We report on the performance of a monitoring system for a prototype calorimeter for the BTeV experiment that uses Lead Tungstate crystals coupled with photomultiplier tubes. The tests were carried out at the 70 GeV accelerator complex at Protvino, Russia.Comment: 12 pages, 8 figures, LaTeX2e, revised versio

Design and performance of LED calibration system prototype for the lead tungstate crystal calorimeter

A highly stable monitoring system based on blue and red light emitting diodes coupled to a distribution network comprised of optical fibers has been developed for an electromagnetic calorimeter that uses lead tungstate crystals readout with photomultiplier tubes. We report of the system prototype design and on the results of laboratory tests. Stability better than 0.1% (r.m.s.) has been achieved during one week of prototype operation.Comment: 10 pages, 6 figures, LaTeX2

Study of Radiation Damage in Lead Tungstate Crystals Using Intense High Energy Beams

We report on the effects of radiation on the light output of lead tungstate crystals. The crystals were irradiated by pure, intense high energy electron and hadron beams as well as by a mixture of hadrons, neutrons and gammas. The crystals were manufactured in Bogoroditsk, Apatity (both Russia), and Shanghai (China). These studies were carried out at the 70-GeV proton accelerator in Protvino

A Multiple-Choice Maze-like Spatial Navigation Task for Humans Implemented in a Real-Space, Multipurpose Circular Arena.

Spatial navigation is a key aspect of human behavior and it is still not completely understood. A number of experimental approaches exist, although most of the published data in the last decades have relied on virtual maze on-screen simulation or not-completely freely moving 3D devices. Some interesting recent developments, such as circular mazes, have contributed to analyze critical aspects of freely moving human spatial navigation in real space, although dedicated protocols only allow for simple approaches. Here, we have developed both specifically designed and home-assembled hardware equipment, and a customized protocol for spatial navigation evaluation in freely moving humans in a real space circular arena. The spatial navigation protocol poses an imitation of a real-space multiple-choice path maze with cul-de-sac and instances of non-linear movement. We have compared the results of this system to those of a number of validated, both virtual and real, spatial navigation tests in a group of participants. The system composed by hardware, the test protocol, and dedicated measure analysis designed in our laboratory allows us to evaluate human spatial navigation in a complex maze with a small and portable structure, yielding a highly flexible, adaptable, and versatile access to information about the subjects’ spatial navigation abilities.P.M. was funded by a predoctoral fellowship (FPI) grant, PRE2020/093032, from the Ministerio de Ciencia e Innovación; E.C. was funded by a predoctoral fellowship (FPI) grant, BES-2017/080415, from the Ministerio de Economía y Competitividad; P.T. was funded by a predoctoral fellowship (FPU) grant, 18/00069, from the Ministerio de Universidades. This research received no other external specific funding

The use of Pd catalysts on carbon-based structured materials for the catalytic hydrogenation of bromates in different types of water

[EN] The aim of this work is to study the activity of new Pd catalysts, supported on two different nano structured carbon materials, for bromate catalytic hydrogenation. The influence of the support has been studied, obtaining the best results with a palladium catalyst supported on carbon nanofibers (CNF) grown in sintered metal fibers (SMF). The results have shown the importance of the catalyst support in order to minimize the mass-transfer limitations ensuring an efficient catalyst use. In this way the most active catalysts are those with a mesoporous structure containing high dispersed Pd nanoparticles. The activity of this catalyst for bromate reduction has been tested in different types of water, namely, distilled water, natural water and industrial wastewater. It has been shown that the catalyst activity depends on the water matrix and bromate reduction rate depends on the hydrogen partial pressure. The potential use of the catalyst has been studied in a continuous reactor. It has been observed that the catalyst is active without any important deactivation at least during 100 h of reaction, but is necessary to avoid salt precipitation and plugging problems.The authors thank the European Union (European Community's Seventh Framework Programme FP7/2007-2013 under grant agreement no. 226347 Project) for financial support. A.E. Palomares also acknowledges the support from the Spanish Government through the project MAT2012-38567-C02-01.Palomares Gimeno, AE.; Franch Martí, C.; Yuranova, T.; Kiwi-Minsker, L.; Garcia Bordeje, JE.; Derrouiche, S. (2014). The use of Pd catalysts on carbon-based structured materials for the catalytic hydrogenation of bromates in different types of water. Applied Catalysis B: Environmental. 146:186-191. https://doi.org/10.1016/j.apcatb.2013.02.056S18619114

Search for Λc+→pK+π−\Lambda_c^+ \to p K^+ \pi^- and Ds+→K+K+π−D_s^+ \to K^+ K^+ \pi^- Using Genetic Programming Event Selection

We apply a genetic programming technique to search for the double Cabibbo suppressed decays $\Lambda_c^+ \to p K^+ \pi^-$ and $D_s^+ \to K^+ K^+ \pi^-$. We normalize these decays to their Cabibbo favored partners and find $\text{BR}($\Lambda_c^+ \to p K^+ \pi^-$)/\text{BR}($\Lambda_c^+ \to p K^- \pi^+$) = (0.05 \pm 0.26 \pm 0.02)$ and $\text{BR}($D_s^+ \to K^+ K^+ \pi^-$)/\text{BR}($D_s^+ \to K^+ K^- \pi^+$) = (0.52\pm 0.17\pm 0.11)$ where the first errors are statistical and the second are systematic. Expressed as 90% confidence levels (CL), we find $< 0.46$ and $< 0.78$ respectively. This is the first successful use of genetic programming in a high energy physics data analysis.Comment: 10 page

Measurement of the D+ and Ds+ decays into K+K-K+

We present the first clear observation of the doubly Cabibbo suppressed decay D+ --> K-K+K+ and the first observation of the singly Cabibbo suppressed decay Ds+ --> K-K+K+. These signals have been obtained by analyzing the high statistics sample of photoproduced charm particles of the FOCUS(E831) experiment at Fermilab. We measure the following relative branching ratios: Gamma(D+ --> K-K+K+)/Gamma(D+ --> K-pi+pi+) = (9.49 +/- 2.17(statistical) +/- 0.22(systematic))x10^-4 and Gamma(Ds+ --> K-K+K+)/Gamma(Ds+ --> K-K+pi+) = (8.95 +/- 2.12(statistical) +2.24(syst.) -2.31(syst.))x10^-3.Comment: 10 pages, 8 figure