The KATRIN experiment aims to determine the neutrino mass scale with a sensitivity of 200
meV
/
c
2
(90% C. L.) by a precision measurement of the shape of the tritium
β
-spectrum in the endpoint ...region. The energy analysis of the decay electrons is achieved by a MAC-E filter spectrometer. To determine the transmission properties of the KATRIN main spectrometer, a mono-energetic and angular-selective electron source has been developed. In preparation for the second commissioning phase of the main spectrometer, a measurement phase was carried out at the KATRIN monitor spectrometer where the device was operated in a MAC-E filter setup for testing. The results of these measurements are compared with simulations using the particle-tracking software “Kassiopeia”, which was developed in the KATRIN collaboration over recent years.
Aims. We performed a spatially resolved spectral X-ray study of the pulsar wind nebula (PWN) in the supernova remnant G0.9+0.1. Furthermore, we modeled its nonthermal emission in the X-ray and very ...high-energy (VHE, E > 100 GeV) γ-ray regime. Methods. Using Chandra ACIS-S3 data, we investigated the east-west dependence of the spectral properties of G0.9+0.1 by calculating hardness ratios. We analyzed the EPIC-MOS and EPIC-pn data of two on-axis observations of the XMM-Newton telescope and extracted spectra of four annulus-shaped regions, centered on the region of brightest emission of the source. A radially symmetric leptonic model was applied in order to reproduce the observed X-ray emission of the inner part of the PWN. Using the optimized model parameter values obtained from the X-ray analysis, we then compared the modeled inverse Compton (IC) radiation with the published H.E.S.S. γ-ray data. Results. The spectral index within the four annuli increases with growing distance to the pulsar, whereas the surface brightness drops. With the adopted model we are able to reproduce the characteristics of the X-ray spectra. The model results for the VHE γ radiation, however, strongly deviate from the H.E.S.S. data.
OBJECTIVES
To describe a small subset of canine solitary cutaneous histiocytoma in which lymph node metastasis has been documented.
METHODS
Cases of dogs with solitary cutaneous histiocytoma lesions ...and regional lymph node metastasis diagnosed via histopathology were found through a retrospective search of the databases of IDEXX Laboratories and the University of California, Davis Veterinary Medical Teaching Hospital Clinical Diagnostic Laboratories. Information on signalment, history and clinical follow‐up was obtained from the submittal form and/or via a questionnaire to the submitting veterinarian. Slides were available for review in seven cases and when possible immunohistochemistry was reviewed or performed by a single pathologist.
RESULTS
Eight cases met the inclusion criteria. The neoplasms had the typical appearance of histiocytomas. All tested samples were immunoreactive for CD18 and lacked immunoreactivity for other lymphocyte markers and CD11d. Immunoreactivity for E‐cadherin varied among the neoplasms tested. Outcome was known for five dogs and at the time of manuscript preparation three of those dogs were alive 1682 days, 570 days and 318 days post‐diagnosis. Of the other two dogs with known outcome, one was euthanased shortly after diagnosis and another was hit by a car. Of the dogs that were eventually lost to follow‐up, one was reported to be disease‐free 1003 days after diagnosis.
CLINICAL SIGNIFICANCE
Metastatic histiocytoma is rarely reported and distinction from aggressive disease processes such as histiocytic sarcoma may be difficult. Based upon a small number of cases with known outcomes, some dogs with solitary metastatic histiocytoma may experience favourable outcomes.
Since the recent experimental findings in the field of neutrino flavor oscillations, one of the most prominent tasks in neutrino physics has been to determine the absolute neutrino mass scale. The ...KATRIN experiment, which is currently being set up at Forschungszentrum Karlsruhe, Germany, will perform a measurement of
m
(
ν
̄
e
)
with a sensitivity of 0.2 eV (90% C.L.). In this talk the electromagnetic design of the KATRIN main spectrometer and the layout of the inner electrode system in particular will be described.
Aims. KATRIN is a neutrino mass experiment based on the kinematics of tritium
β
-decay. This work presents the methods employed at KATRIN to reduce the spectrometer-related background.
Methods. The ...electrode system of the main spectrometer includes a modular double-layer wire grid for electrostatic screening of background. The key features of the wire electrode and the underlying design criteria of the optimisation procedure are described.
Status. Fabrication of the wire electrode modules is completed and installation into the KATRIN main spectrometer has started.
The KATRIN experiment is going to search for the mass of the electron antineutrino down to 0.2eV/
c
2
. In order to reach this sensitivity the background rate has to be understood and minimised to ...0.01 counts per second. One of the background sources is the unavoidable Penning-like trap for electrons due to the combination of the electric and magnetic fields between the pre- and the main spectrometer at KATRIN. In this article we will show that by sweeping a conducting wire periodically through such a particle trap stored particles can be removed, an ongoing discharge in the trap can be stopped, and the count rate measured with a detector looking at the trap is reduced.
The objective of the Karlsruhe Tritium Neutrino (KATRIN) experiment is to determine the effective electron neutrino mass
m
(
ν
e
)
with an unprecedented sensitivity of
0.2
eV
/
c
2
(
90
%
C.L.
) by ...precision electron spectroscopy close to the endpoint of the
β
-decay of tritium. We present a consistent theoretical description of the
β
-electron energy spectrum in the endpoint region, an accurate model of the apparatus response function, and the statistical approaches suited to interpret and analyze tritium
β
-decay data observed with KATRIN with the envisaged precision. In addition to providing detailed analytical expressions for all formulae used in the presented model framework with the necessary detail of derivation, we discuss and quantify the impact of theoretical and experimental corrections on the measured
m
(
ν
e
)
. Finally, we outline the statistical methods for parameter inference and the construction of confidence intervals that are appropriate for a neutrino mass measurement with KATRIN. In this context, we briefly discuss the choice of the
β
-energy analysis interval and the distribution of measuring time within that range.
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