In this work we investigate and parameterize the amount and angular distribution of Cherenkov photons, which are generated by low-energy secondary particles (typically \(\lesssim 500 \)\,MeV), which ...accompany a muon track in water or ice. These secondary particles originate from small energy loss processes. We investigate the contributions of the different energy loss processes as a function of the muon energy and the maximum transferred energy. For the calculation of the angular distribution we have developed a generic transformation method, which allows us to derive the angular distribution of Cherenkov photons for an arbitrary distribution of track directions and their velocities.
The Jiangmen Neutrino Underground Observatory (JUNO) is a 20\(\,\)kton liquid scintillator detector currently under construction near Kaiping in China. The physics program focuses on the ...determination of the neutrino mass hierarchy with reactor anti-neutrinos. For this purpose, JUNO is located 650\(\,\)m underground with a distance of 53\(\,\)km to two nuclear power plants. As a result, it is exposed to a muon flux that requires a precise muon reconstruction to make a veto of cosmogenic backgrounds viable. Established muon tracking algorithms use time residuals to a track hypothesis. We developed an alternative muon tracking algorithm that utilizes the geometrical shape of the fastest light. It models the full shape of the first, direct light produced along the muon track. From the intersection with the spherical PMT array, the track parameters are extracted with a likelihood fit. The algorithm finds a selection of PMTs based on their first hit times and charges. Subsequently, it fits on timing information only. On a sample of through-going muons with a full simulation of readout electronics, we report a spatial resolution of 20\(\,\)cm of distance from the detector's center and an angular resolution of 1.6\(\,^{\circ}\) over the whole detector. Additionally, a dead time estimation is performed to measure the impact of the muon veto. Including the step of waveform reconstruction on top of the track reconstruction, a loss in exposure of only 4% can be achieved compared to the case of a perfect tracking algorithm. When including only the PMT time resolution, but no further electronics simulation and waveform reconstruction, the exposure loss is only 1%.
IceCube, a cubic-kilometer sized neutrino detector at the Geographic South Pole, has recently discovered a diffuse all-flavor flux of astrophysical neutrinos. However, the corresponding astrophysical ...sources have not yet been identified in current IceCube analyses. We present a method to interpret the results of a recently published angular correlation analysis in IceCube searching for spatial clustering of muon neutrino events in terms of astrophysical models (given by an arbitrary source count distribution). We exemplarily show the resulting limits on the parameters of a class of source count distributions motivated by Fermi-LAT observations of resolved blazars.
The IceCube Neutrino Observatory will be upgraded with about 700 additional optical sensor modules and new calibration devices. Particularly, improved calibration will enhance IceCube's physics ...capabilities both at low and high neutrino energies. An important ingredient for a good angular resolution of the observatory is a precise calibration of the positions of optical sensors. We present the concept of newly developed acoustic sensors that are mounted inside the optical modules and additional acoustic emitter modules that are attached to the strings. With this system we aim for the calibration of the detectors' geometry with a precision of 10\,cm by means of trilateration of the arrival times of acoustic signals. This new method will allow for an improved and complementary geometry calibration with respect to previously used methods based on optical flashers and drill logging data.
We present a model-independent interpretation of searches for dark matter annihilation in the Sun using an effective field theory approach. We identify a set of effective operators contributing to ...spin-dependent scattering of dark matter with protons in the non-relativistic limit and explore simple new physics models which would give rise to such operators. Using the limits on the spin-dependent scattering cross-section set by the IceCube collaboration in their search for dark matter annihilation in the Sun, we derive limits on effective couplings and corresponding masses of mediating particles. We show that the effective field theory interpretation of the IceCube searches provides constraints on dark matter complementary to those from relic density observations and searches at the LHC. Finally, we discuss the impact of astrophysical uncertainties on our results.
The Serappis (SEarch for RAre PP-neutrinos In Scintillator) project aims at a
precision measurement of the flux of solar $pp$ neutrinos on the few-percent
level. Such a measurement will be a relevant ...contribution to the study of solar
neutrino oscillation parameters and a sensitive test of the solar luminosity
constraint. The concept of Serappis relies on a small organic liquid
scintillator detector ($\sim$20 m$^3$) with excellent energy resolution
($\sim$2.5 % at 1 MeV), low internal background and sufficient shielding from
surrounding radioactivity. This can be achieved by a minor upgrade of the
OSIRIS facility at the site of the JUNO neutrino experiment in southern China.
To go substantially beyond current accuracy levels for the $pp$ flux, an
organic scintillator with ultra-low $^{14}$C levels (below $10^{-18}$) is
required. The existing OSIRIS detector and JUNO infrastructure will be
instrumental in identifying suitable scintillator materials, offering a unique
chance for a low-budget high-precision measurement of a fundamental property of
our Sun that will be otherwise hard to access.
A unified supernova catalogue Lennarz, Dirk; Altmann, David; Wiebusch, Christopher
arXiv.org,
02/2012
Paper, Journal Article
Open access
In this paper a new supernova catalogue containing data for 5526 extragalactic supernovae that were discovered up to 2010 December 31 is presented. It combines several catalogues that are currently ...available online in a consistent and traceable way. During the comparison of the catalogues inconsistent entries were identified and resolved where possible. Remaining inconsistencies are marked transparently and can be easily identified. Thus it is possible to select a high-quality sample in a most simple way. Where available, redshift-based distance estimates to the supernovae were replaced by journal-refereed distances. Examples of statistical studies that are now possible with this new catalogue are presented in this paper.
Telescopes, designed with semi-conductor based photo sensors, have the potential to detect Cherenkov or fluorescence light emitted by cosmic-rays in the atmosphere. Such telescopes promise a high ...duty cycle and efficiency in remote harsh environments. Given the relatively low costs and robustness of these instruments, this technology could prove interesting especially if deployed in large numbers with existing and future extended cosmic-ray and gamma ray detectors, including the Pierre Auger observatory, HAWC, IceCube and CTA. They may have the potential to enhance the sensitivity of these instruments for the detection of high-energy gamma rays and cosmic-ray air showers. In addition, for neutrino telescopes such a technology could prove to be an efficient cosmic-ray veto on the surface. In this contribution the current motivation, design, and development of a prototype SiPM based air Cherenkov telescope is described. The results of initial sensitivity studies, and the readiness of the system for first tests, including those proposed for the South Pole are shown.
Sam 's case, like many cases of Autism Spectrum Disorders (ASD), can challenge the usual approach to neuropsychological assessment. It illustrates one application of Applied Behavior Analysis (ABA) ...treatment and the incorporation of an assessment model different from the typical rigorous use of norm-referenced instruments. The criterion-referenced measure does not produce standard scores or age equivalents but, rather, identifies more fine-tuned, skill-specific targets for treatment as well as progress toward treatment goals through regular reevaluation. Such an approach can be a highly practical resource that is directly applicable to treatment, steering intervention by providing information not available from norm-referenced measures of broader ability areas.
Sam was the first child born to a loving family, who watched him respond to noises and speech as an infant and develop cooing, babbling, and jargon prior to age 2. His language development stopped, and he became less verbal and generally appeared less happy at the age of 19 months. He no longer laughed and giggled as he had previously, and he would engage in prolonged periods of staring or rolling toy trains or cars back and forth. He did not respond when called. His parents wondered whether these changes related to the coincident birth of his sister, with whom he would not interact at the time. Speech and language evaluation at age 2 years and 3 months noted extremely limited expressive (9 – 12 month age-range) and receptive (6 – 9 month age-range) language. Screening at that time indicated normal hearing. When Sam was aged 2 years and 6 months, speech therapy observations described the following as significant progress: he would leave the couch, allow a therapist to touch him, respond to his name by turning his head when called, and use one to two words. He preferred isolation. Although these observations were intended to communicate progress, they also reflected the severity of Sam 's troubling symptoms. Although the difficulties were considered communication-related at the time, the implication that he had not been responding when called by name was a meaningful clue of his impending broader ASD diagnosis. An Early Childhood educational evaluation conducted in Sam 's home when he was aged 2 years and 10 months indicated that he seemed aware of actions around him but that he had poor eye contact and spoke mainly with jargon and screeches. Particular delay in social and emotional skills was noted. Sam 's parents, attuned to developmental concerns, attempted biological interventions often advocated for children with his profile, including a casein (gluten) free diet and vitamin supplements, without obvious benefit.
IceCube-DeepCore is a compact Cherenkov detector located in the clear ice of the bottom center of the IceCube Neutrino Telescope. Its purpose is to enhance the sensitivity of IceCube for low neutrino ...energies (< 1 TeV) and to lower the detection threshold of IceCube by about an order of magnitude to below 10 GeV. The detector is formed by 6 additional strings of 360 high quantum efficiency phototubes together with the 7 central IceCube strings. The improved sensitivity will provide an enhanced sensitivity to probe a range of parameters of dark matter models not covered by direct experiments. It opens a new window for atmospheric neutrino oscillation measurements of muon neutrino disappearance or tau neutrino appearance in an energy region not well tested by previous experiments, and enlarges the field of view of IceCube to a full sky observation when searching for potential neutrino sources. The first string was succesfully installed in January 2009, commissioning of the full detector is planned early 2010.
