Advances in particle identification in AMS at low energies

Abstract The DeepCore sub-array within the IceCube Neutrino Observatory is a densely instrumented region of Antarctic ice designed to observe atmospheric neutrino interactions above 5 GeV via Cherenkov radiation. An essential aspect of any neutrino oscillation analysis is the ability to accurately identify the flavor of neutrino events in the detector. This task is particularly difficult at low energies when very little light is deposited in the detector. Here we discuss the use of machine learning to perform event classification at low energies in IceCube using a boosted decision tree (BDT). A BDT is trained using reconstructed quantities to identify track-like events, which result from muon neutrino charged current interactions. This new method improves the accuracy of particle identification compared to traditional classification methods which rely on univariate straight cuts.

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Microanalysis of precipitates in a ferritic steel

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100110234 ◽

1978 ◽

Vol 36 (1) ◽

pp. 618-619

Author(s):

J.M. Titchmarsh

Keyword(s):

Ferritic Steel ◽

Particle Identification ◽

Energy Dispersive ◽

Objective Lens ◽

Ferritic Steels ◽

Replica Technique ◽

X Ray ◽

Large Numbers ◽

Scanning Transmission ◽

Made In

The advances in recent years in the microanalytical capabilities of conventional TEM's fitted with probe forming lenses allow much more detailed investigations to be made of the microstructures of complex alloys, such as ferritic steels, than have been possible previously. In particular, the identification of individual precipitate particles with dimensions of a few tens of nanometers in alloys containing high densities of several chemically and crystallographically different precipitate types is feasible. The aim of the investigation described in this paper was to establish a method which allowed individual particle identification to be made in a few seconds so that large numbers of particles could be examined in a few hours.A Philips EM400 microscope, fitted with the scanning transmission (STEM) objective lens pole-pieces and an EDAX energy dispersive X-ray analyser, was used at 120 kV with a thermal W hairpin filament. The precipitates examined were extracted using a standard C replica technique from specimens of a 2¼Cr-lMo ferritic steel in a quenched and tempered condition.

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Fresnel interference in point-projection imaging of purple membrane

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100140609 ◽

1995 ◽

Vol 53 ◽

pp. 846-847

Author(s):

X. Zhang ◽

J. Spence ◽

W. Qian ◽

D. Taylor ◽

K. Taylor

Keyword(s):

Detection Efficiency ◽

Mean Free Path ◽

Purple Membrane ◽

Unit Cell Dimension ◽

Experimental Point ◽

Membrane Thickness ◽

Low Energies ◽

Channel Plate ◽

Point Projection ◽

Inelastic Mean Free Path

Experimental point-projection shadow microscope (PPM) images of uncoated, unstained purple membrane (PM, bacteriorhodopsin, a membrane protein from Halobacterium holobium) were obtained recently using 100 volt electrons. The membrane thickness is about 5 nm and the hexagonal unit cell dimension 6 nm. The images show contrast around the edges of small holes, as shown in figure 1. The interior of the film is opaque. Since the inelastic mean free path for 100V electrons in carbon (about 6 Å) is much less than the sample thickness, the question arises that how much, if any, transmission of elastically scattered electrons occurs. A large inelastic contribution is also expected, attenuated by the reduced detection efficiency of the channel plate at low energies. Quantitative experiments using an energy-loss spectrometer are planned. Recently Shedd has shown that at about 100V contrast in PPM images of thin gold films can be explained as Fresnel interference effects between different pinholes in the film, separated by less than the coherence width.

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Electrical Damage Due to Low Energy Plasma Processing of GaAs Structures

MRS Proceedings ◽

10.1557/proc-223-209 ◽

1991 ◽

Vol 223 ◽

Author(s):

Hans P. Zappe ◽

Gudrun Kaufel

Keyword(s):

Chemical Processes ◽

Low Energy ◽

Electrical Behavior ◽

Rapid Thermal Anneal ◽

High Temperature Anneal ◽

Significant Damage ◽

Low Energies ◽

Long Time ◽

Physical Plasma

ABSTRACTThe effect of numerous plasma reative ion etch and physical milling processes on the electrical behavior of GaAs bulk substrates has been investigated by means of electric microwave absorption. It was seen that plasma treatments at quite low energies may significantly affect the electrical quality of the etched semiconductor. Predominantly physical plasma etchants (Ar) were seen to create significant damage at very low energies. Chemical processes (involving Cl or F), while somewhat less pernicious, also gave rise to electrical substrate damage, the effect greater for hydrogenic ambients. Whereas rapid thermal anneal treatments tend to worsen the electrical integrity, some substrates respond positively to long-time high temperature anneal steps.

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Response of $D^0$ U-LAr Calorimeters at Low-Energies and the Effect of Oxygen Contamination on Observed Signals

10.2172/1424424 ◽

1994 ◽

Author(s):

Robert James Hirosky

Keyword(s):

Oxygen Contamination ◽

Low Energies ◽

Effect Of Oxygen

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Effects of the solar wind termination shock and heliosheath on theheliospheric modulation of galactic and anomalous Helium

Annales Geophysicae ◽

10.5194/angeo-22-3063-2004 ◽

2004 ◽

Vol 22 (8) ◽

pp. 3063-3072 ◽

Cited By ~ 15

Author(s):

U. W. Langner ◽

M. S. Potgieter

Keyword(s):

Solar Wind ◽

Cosmic Ray ◽

Magnetic Polarity ◽

Termination Shock ◽

Shock Acceleration ◽

Diffusive Shock Acceleration ◽

Cosmic Ray Modulation ◽

Low Energies ◽

Solar Wind Termination Shock ◽

Charge Sign

Abstract. The interest in the role of the solar wind termination shock and heliosheath in cosmic ray modulation studies has increased significantly as the Voyager 1 and 2 spacecraft approach the estimated position of the solar wind termination shock. The effect of the solar wind termination shock on charge-sign dependent modulation, as is experienced by galactic cosmic ray Helium (He++) and anomalous Helium (He+), is the main topic of this work, and is complementary to the previous work on protons, anti-protons, electrons, and positrons. The modulation of galactic and anomalous Helium is studied with a numerical model including a more fundamental and comprehensive set of diffusion coefficients, a solar wind termination shock with diffusive shock acceleration, a heliosheath and particle drifts. The model allows a comparison of modulation with and without a solar wind termination shock and is applicable to a number of cosmic ray species during both magnetic polarity cycles of the Sun. The modulation of Helium, including an anomalous component, is also done to establish charge-sign dependence at low energies. We found that the heliosheath is important for cosmic ray modulation and that its effect on modulation is very similar for protons and Helium. The local Helium interstellar spectrum may not be known at energies

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