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arXiv2014

A Smartphone Controlled Handheld Microfluidic Liquid Handling System

Microfluidics and lab-on-a-chip technologies have made it possible to manipulate small volume liquids with unprecedented resolution, automation and integration. However, most current microfluidic systems still rely on bulky off-chip infrastructures such as compressed pressure sources, syringe pumps and computers to achieve complex liquid manipulation functions. Here, we present a handheld automated microfluidic liquid handling system controlled by a smartphone, which is enabled by combining elastomeric on-chip valves and a compact pneumatic system. As a demonstration, we show that the system can automatically perform all the liquid handling steps of a bead-based sandwich immunoassay on a multi-layer PDMS chip without any human intervention. The footprint of the system is 6 by 10.5 by 16.5cm, and the total weight is 829g including battery. Powered by a 12.8V 1500mAh Li battery, the system consumed 2.2W on average during the immunoassay and lasted for 8.7 hrs. This handheld microfluidic liquid handling platform is generally applicable to many biochemical and cell-based assays requiring complex liquid manipulation and sample preparation steps such as FISH, PCR, flow cytometry and nucleic acid sequencing. In particular, the integration of this technology with read-out biosensors may help enable the realization of the long-sought Tricorder-like handheld in-vitro diagnostic (IVD) systems.

physics.ins-det↗

arXiv2014

Energy dependence of W values for protons in hydrogen

The mean energy $W$ required to produce an ion pair in molecular hydrogen has been obtained for protons in the energy range between 1 MeV and 4.5 MeV. The W values were derived from the existing experimental data on elastic {\it $π^-$p} scattering at the beam energy of 40 GeV. In the experiment, the ionization chamber IKAR filled with hydrogen at a pressure of 10 at served simultaneously as a gas target and a detector for recoil protons. For selected events of elastic scattering, the ionization yield produced by recoil protons was measured in IKAR, while the energy was determined kinematically through the scattering angles of the incident particles measured with a system of multi-wire proportional chambers. The ionization produced by $α$-particles from $α$-sources of $^{234}$U deposited on the chamber electrodes was used for absolute normalization of the W values. The energy dependence of $W$ for protons in H$_2$ shows an anomalous increase of $W$ with increasing energy in the measured energy range. At the energy of 4.76 MeV, the ionization yield for alpha particles is by 2\% larger than that for protons.

physics.ins-det↗

arXiv2014

First Dark Matter Search Results from the Large Underground Xenon (LUX) Experiment

The Large Underground Xenon (LUX) dark matter experiment is operating 1.5 km underground at the Sanford Underground Research Facility in Lead, South Dakota, USA. In 2013, the experiment had a WIMP search exposure of 10,091 kg-days over a period of 85.3 live-days. This first dark matter search placed the world's most stringent limits on WIMP-nucleon interaction cross-sections over a wide range of WIMP masses, and is in tension with signal hints of low-mass WIMPs from DAMA, CoGeNT and CDMS-II Si. LUX will commence a 300 day run in 2014 that will improve the sensitivity by a factor of 5. Low-energy calibrations obtained from a neutron double-scattering technique will further constrain and reduce systematics, particularly for low WIMP masses.

hep-ex↗

arXiv2014

Proposal for SPS beam time for the baby MIND and TASD neutrino detector prototypes

The design, construction and testing of neutrino detector prototypes at CERN are ongoing activities. This document reports on the design of solid state baby MIND and TASD detector prototypes and outlines requirements for a test beam at CERN to test these, tentatively planned on the H8 beamline in the North Area, which is equipped with a large aperture magnet. The current proposal is submitted to be considered in light of the recently approved projects related to neutrino activities with the SPS in the North Area in the medium term 2015-2020.

physics.ins-det↗

arXiv2015

Uncertainties analysis of fission fraction for reactor antineutrino experiments

Reactor antineutrino experiment are used to study neutrino oscillation, search for signatures of nonstandard neutrino interaction, and monitor reactor operation for safeguard application. Reactor simulation is an important source of uncertainties for a reactor neutrino experiment. Commercial code is used for reactor simulation to evaluate fission fraction in Daya Bay neutrino experiment, but the source code doesn't open to our researcher results from commercial secret. In this study, The open source code DRAGON was improved to calculate the fission rates of the four most important isotopes in fissions, $^{235}$U,$^{238}$U,$^{239}$Pu and $^{241}$Pu, and then was validated for PWRs using the Takahama-3 benchmark. The fission fraction results are consistent with those of MIT's results. Then, fission fraction of Daya Bay reactor core was calculated by using improved DRAGON code, and the fission fraction calculated by DRAGON agreed well with these calculated by SCIENCE. The average deviation less than 5\% for all the four isotopes. The correlation coefficient matrix between $^{235}$U,$^{238}$U,$^{239}$Pu and $^{241}$Pu were also studied using DRAGON, and then the uncertainty of the antineutrino flux by the fission fraction was calculated by using the correlation coefficient matrix. The uncertainty of the antineutrino flux by the fission fraction simulation is 0.6\% per core for Daya Bay antineutrino experiment. The uncertainties source of fission fraction calculation need further to be studied in the future.

nucl-ex↗

arXiv2014

Initial report from the ICFA Neutrino Panel

In July 2013 ICFA established the Neutrino Panel with the mandate "To promote international cooperation in the development of the accelerator-based neutrino-oscillation program and to promote international collaboration in the development a neutrino factory as a future intense source of neutrinos for particle physics experiments". This, the Panel's Initial Report, presents the conclusions drawn by the Panel from three regional "Town Meetings" that took place between November 2013 and February 2014. After a brief introduction and a short summary of the status of the knowledge of the oscillation parameters, the report summarises the approved programme and identifies opportunities for the development of the field. In its conclusions, the Panel recognises that to maximise the discovery potential of the accelerator-based neutrino-oscillation programme it will be essential to exploit the infrastructures that exist at CERN, FNAL and J-PARC and the expertise and resources that reside in laboratories and institutes around the world. Therefore, in its second year, the Panel will consult with the accelerator-based neutrino-oscillation community and its stakeholders to: develop a road-map for the future accelerator-based neutrino-oscillation programme that exploits the ambitions articulated at CERN, FNAL and J-PARC and includes the programme of measurement and test-beam exposure necessary to ensure the programme is able to realise its potential; develop a proposal for a coordinated "Neutrino RD" programme, the accelerator and detector R&D programme required to underpin the next generation of experiments; and to explore the opportunities for the international collaboration necessary to realise the Neutrino Factory.

physics.acc-ph↗

arXiv2014

Wideband Microstrip Antenna Design

This paper covers wideband planar antenna design approaches. Modeling and simulation results were obtained using ADS simulation software and have demonstrated feasibility for fabrication of a wideband patch antenna configuration for moderately low-power applications.

physics.ins-det↗

arXiv2014

PM noise Measurement at W-Band

We present improved performance for a 92 to 96 GHz cross-spectrum phase modulated (PM) noise measurement system reported. The system is principally designed to measure amplifiers in pulsed mode as well as in CW mode at a given pulse repetition frequency. This paper reports only the CW mode of operation. Data for the noise-floor of the measurement system as well as PM noise of several W- band active components are presented. This work also discusses an improved performance frequency synthesizer that operates in the 92 to 96 GHz range.

physics.ins-det↗

arXiv2014

An option of "UCN pump" for ESS

The aim of this short note is to present an option for a source of ultracold neutrons (UCNs), which could profit from the pulse time-structure of the future ESS spallation neutron source in Lund, and thus which could produce a very high UCN density and a rather high UCN flux simultaneously. In order to realize this idea one has to install a relatively thin solid-deuterium UCN source in a close vicinity to the spallation target and to couple it with an extraction UCN guide with an entrance membrane window, which is moving periodically and synchronously with the operation cycle of the spallation source, as explained in the text below. This proposal profits from the fact that all characteristic parameters of the problem, such as the pulse duration of the ESS spallation source, the typical thickness of solid deuterium source that could be easily realized, the typical time of generation of UCNs in solid deuterium, the length and diameter of the extraction neutron guide and the time diagram of the membrane motion that is still realistic, they all fit nicely to optimum desired parameters. The UCN density produced in such a way could approach 10^6 UCN/cm3.

physics.ins-det↗

arXiv2014

Recent Borexino results and prospects for the near future

The Borexino experiment, located in the Gran Sasso National Laboratory, is an organic liquid scintillator detector conceived for the real time spectroscopy of low energy solar neutrinos. The data taking campaign phase I (2007 - 2010) has allowed the first independent measurements of 7Be, 8B and pep fluxes as well as the first measurement of anti-neutrinos from the earth. After a purification of the scintillator, Borexino is now in phase II since 2011. We review here the recent results achieved during 2013, concerning the seasonal modulation in the 7Be signal, the study of cosmogenic backgrounds and the updated measurement of geo-neutrinos. We also review the upcoming measurements from phase II data (pp, pep, CNO) and the project SOX devoted to the study of sterile neutrinos via the use of a 51Cr neutrino source and a 144Ce-144Pr antineutrino source placed in close proximity of the active material.

hep-ex↗

arXiv2014

Search for Dark Matter with Liquid Argon and Pulse Shape Discrimination: Results from DEAP-1 and Status of DEAP-3600

In the last decade, Direct Dark Matter searches has become a very active research program, spawning dozens of projects world wide and leading to contradictory results. It is on this stage that the Dark matter Experiment with liquid Argon and Pulse shape discrimination (DEAP) is about to enter. With a 3600~kg liquid argon target and a 1000~kg fiducial mass, it is designed to run background free during 3 years, reaching an unprecedented sensitivity of 10$^{-46}$~cm$^2$ for a WIMP mass of 100 GeV. In order to achieve this impressive feat, the collaboration followed a two-pronged approach: a careful selection of every material entering the construction of the detector in order to suppress the backgrounds, and optimum use of the pulse shape discrimination (PSD) technique to separate the nuclear recoils from the electronic recoils. Using the experience acquired ffrom the 7~kg-prototype DEAP-1, a 3600~kg detector is being completed at SNOLAB (Sudbury, CANADA) and is expected to start taking data in mid-2014.

astro-ph.IM↗

arXiv2014

A Novel Light Source Design for Spectral Tuning in Biomedical Imaging

We propose a novel architecture with a remote phosphor based modular and compact light source in a non-contact dermoscope prototype for skin cancer screening. The spectrum and color temperature of the output light can easily and significantly be changed depending on spectral absorption characteristics of the tissues being imaged. The new system has several advantages compared to state-of-the-art phosphor converted ultra-bright white LEDs, used in a wide range of medical imaging devices, which have a fixed spectrum and color temperature at a given operating point. In particular, the system can more easily be adapted to the requirements originating from different tissues in the human body which have wavelength dependent absorption and reflectivity. This leads to improved contrast for different kinds of imaged tissue components. The concept of such a lighting architecture can be vastly utilized in many other medical imaging devices including endoscopic systems.

physics.med-ph↗

arXiv2014

Measurement of neutron total cross-sections of 209Bi at the Pohang Neutron Facility

Measurements of neutron total cross-sections of natural bismuth in the neutron energy region from 0.1 eV to 100 eV have been performed by using the time-of-flight method at the Pohang Neutron Facility, which consists of an electron linear accelerator, a water-cooled tantalum target with a water moderator, and a 12-m-long time-of-flight path. A 6Li-ZnS(Ag) scintillator with a diameter of 12.5 cm and a thickness of 1.6 cm is employed as a neutron detector, and a piece of high purity natural bismuth metallic plates with a thickness of 3 mm is used for the neutron transmission measurement. The present results were compared with the evaluated data from ENDF/B VII.1 and other previous reported experimental data.

nucl-ex↗

arXiv2014

Artificial Neural Network as a FPGA Trigger for a Detection of Very Inclined Air Showers

Neutrinos can interact in the atmosphere (downward-going ν) or in the Earth crust (Earth-skimming ν), producing air showers that can be observed with arrays of detectors at the ground. The surface detector array of the Pierre Auger Observatory can detect these types of cascades. The distinguishing signature for neutrino events is the presence of very inclined showers produced close to the ground (i.e., after having traversed a large amount of atmosphere). Up to now, the Pierre Auger Observatory did not find any candidate for a neutrino event. A very low rate of events potentially generated by neutrinos is a significant challenge for a detection technique and requires both sophisticated algorithms and high-resolution hardware. We present a trigger based on a pipeline artificial neural network (ANN) implemented in a large FPGA which after learning can recognize traces corresponding to special types of events. The structure of an ANN algorithm being developed on the MATLAB platform has been implemented into the fast logic of the biggest Cyclone V E FPGA used for the prototype of the Front-End Board for the Auger-Beyond-2015 effort. Several algorithms were tested, however, the Levenberg-Marquardt one seems to be the most efficient. The network was taught: a) to recognize "old" showers (learning on a basis of real very inclined Auger showers (positive markers) and real standard showers especially triggered by Time over Threshold (negative marker), b) to recognize "young" showers (on the basis of simulated "young" events (positive markers) and standard Auger events as a negative reference). A three-layer neural network being taught by real very inclined Auger showers shows a good efficiency in pattern recognition of 16-point traces with profiles characteristic of "old" showers.

physics.ins-det↗

arXiv2014

Front-End Board with Cyclone V as a Test High-Resolution Platform for the Auger-Beyond-2015 Front End Electronics

The surface detector (SD) array of the Pierre Auger Observatory containing at present 1680 water Cherenkov detectors spread over an area of 3000 km^2 started to operate since 2004. The currently used Front-End Boards are equipped with no-more produced ACEX and obsolete Cyclone FPGA (40 MSps/15-bit of dynamic range). Huge progress in electronics and new challenges from physics impose a significant upgrade of the SD electronics either to improve a quality of measurements (much higher sampling and much wider dynamic range) or pick-up from a background extremely rare events (new FPGA algorithms based on sophisticated approaches like e.g. spectral triggers or neural networks). Much higher SD sensitivity is necessary to confirm or reject hypotheses critical for a modern astrophysics. The paper presents the Front-End Board (FEB) with the biggest Cyclone V E FPGA 5CEFA9F31I7N, supporting 8 channels sampled with max. 250 MSps @ 14-bit resolution. Considered sampling for the SD is 120 MSps, however, the FEB has been developed with external anti-aliasing filters to keep a maximal flexibility. Six channels are targeted to the SD, two the rest for other experiments like: Auger Engineering Radio Array and additional muon counters. The FEB is an intermediate design pluged-in the actually used Unified Board communicating with micro-controller at 40 MHz, however providing even 250 MSPs sampling with 20-bit dynamic range, equipped in a virtual NIOS processor and supporting 256 MB of SDRAM as well as with an implemented spectral trigger based on the Discrete Cosine Transform for a detection of very inclined "old" showers. The FEB can also support a neural network developing for a detection of "young" showers, potentially generated by neutrinos.

physics.ins-det↗

arXiv2014

Photon activation analysis of the scraper in a 200-MeV electron accelerator using gamma-spectrometry depth profiling

For a high energy electron facility, the estimates of induced radioactivity in materials are of major importance to keep exposure to personnel and to the environment as low as reasonably achievable. In addition, an accurate prediction of induced radioactivity is also essential for the design, operation and decommissioning of a high energy electron linear accelerator. The research of induced radioactivity focuses on the photonuclear reaction, whose giant resonance response in the copper is ranging from 10 MeV to 28 MeV. The 200 MeV electron linac of NSRL is one of the earliest high-energy electron linear accelerators in P. R. China. The electrons are accelerated to 200 MeV by five acceleration tubes and collimated by the scrapers made of copper. At present, it is the first retired high-energy electron linear accelerator in domestic. Its decommissioning provides an efficient way for the induced radioactivity research of such accelerators, and is a matter of great significance to the accumulation of the induced radioactivity experience. When the copper target is impacted by an 158 MeV electron beam, the number of photons generated whose energy are in the range of giant resonance response is the largest. Thus, this paper focuses on the induced radioactivity for a copper target impacted by the 158 MeV electron beam. The slicing method is applied in the research. The specific activity of each slice was measured at cooling times of ten months and the results were compared with the prediction from the Monte-Carlo program FLUKA. The simulation results are in good agreement with the measurement results. The method by Monte Carlo simulation in this paper gives a reasonable prediction of the induced radioactivity problem for the high-energy electron linear accelerators, laying a foundation for the accumulation of the induced radioactivity experience.

physics.ins-det↗

arXiv2014

Report on Gamma-Ray Analysis of Seaweed Samples from Naturespirit Herbs LLC

Five seaweed samples from Naturespirit Herbs LLC were counted using low-background high-resolution gamma-ray detectors to search for evidence of contamination from the Fukushima reactor accident. No evidence of Cs-134 was observed in any of the samples. Very low levels of Cs-137 were observed and are attributed to fallout from atmospheric nuclear weapons testing. However, these levels of Cs-137 are small compared to the levels of the naturally occurring K-40 observed from these seaweed samples.

nucl-ex↗

arXiv2014

Plasma Temperature Inference from DT/DD Neutron Discrimination

DD and DT reaction rates may be compared to determine plasma temperatures in the 10--200 eV range. Distinguishing neutrons from these two reactions is difficult when yields are low or unpredictable. Time of flight methods fail if the source is extended in time. These neutrons may be distinguished because inelastic scattering of more energetic neutrons by carbon produces a 4.44 Mev gamma-ray, and because hydrogenous material preferentially attenuates lower energy neutrons. We describe a detector system that can discriminate between lower and higher energy neutrons for fluences as low as $\mathcal{O}(10^2)$ neutrons/sterad even when time of flight methods fail, define a figure of merit and calculate its performance over a broad range of parameters.

physics.ins-det↗