Modelling of gas dynamical properties of the KATRIN tritium source and implications for the neutrino mass measurement

The KATRIN experiment aims to measure the effective mass of the electron antineutrino from the analysis of electron spectra stemming from the beta-decay of molecular tritium with a sensitivity of 200 meV. Therefore, a daily throughput of about 40 g of gaseous tritium is circulated in a windowless source section. An accurate description of the gas flow through this section is of fundamental importance for the neutrino mass measurement as it significantly influences the generation and transport of beta-decay electrons through the experimental setup. In this paper we present a comprehensive model consisting of calculations of rarefied gas flow through the different components of the source section ranging from viscous to free molecular flow. By connecting these simulations with a number of experimentally determined operational parameters the gas model can be refreshed regularly according to the measured operating conditions. In this work, measurement and modelling uncertainties are quantified with regard to their implications for the neutrino mass measurement. We find that the systematic uncertainties related to the description of gas flow are represented by $\Delta m_{\nu}^2=(-3.06\pm 0.24)\cdot10^{-3}$ eV$^2$, and that the gas model is ready to be used in the analysis of upcoming KATRIN data.Comment: 28 pages, 13 figure

β\beta-Decay Spectrum, Response Function and Statistical Model for Neutrino Mass Measurements with the KATRIN Experiment

The objective of the Karlsruhe Tritium Neutrino (KATRIN) experiment is to determine the effective electron neutrino mass $m(\nu_\text{e})$ with an unprecedented sensitivity of $0.2\,\text{eV}$ (90\% C.L.) by precision electron spectroscopy close to the endpoint of the $\beta$ decay of tritium. We present a consistent theoretical description of the $\beta$ 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 $\beta$ 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 $m(\nu_\text{e})$. 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 $\beta$ energy analysis interval and the distribution of measuring time within that range.Comment: 27 pages, 22 figures, 2 table

A UV LED-based fast-pulsed photoelectron source for time-of-flight studies

We report on spectroscopy and time-of-flight measurements using an 18 keV fast-pulsed photoelectron source of adjustable intensity, ranging from single photoelectrons per pulse to 5 photoelectrons per microsecond at pulse repetition rates of up to 10 kHz. Short pulses between 40 ns and 40 microseconds in length were produced by switching light emitting diodes with central output wavelengths of 265 nm and 257 nm, in the deep ultraviolet (or UV-C) regime, at kHz frequencies. Such photoelectron sources can be useful calibration devices for testing the properties of high-resolution electrostatic spectrometers, like the ones used in current neutrino mass searches.Comment: 16 pages, 11 figure

Desain Dan Analisis Struktur Rangka Motorcycle Lift Menggunakan Perangkat Lunak Solidworks

Structural analysis is the science of determining the effects of loads on physical structures and their components. Structural analysis combines the fields of engineering mechanics, materials engineering, and engineering mathematics to calculate deformation of structures, internal forces, stresses, bearing reactions, accelerations, and stability. The designer chooses solidwork software for design and analysis because this software can properly simulate the design and calculation of forces on machine tools and elements. Solidwork contains a collection of simulation programs that are easy to use and can be used to create part programs and material selection used for mechanical analysis at work in order to obtain stress, displacement and safety factors (factory safety). The designed motorcycle lift features a chrome stainless steel frame with a control system, with main dimensions 1800 mm length, 700 mm width and 200 mm height at minimum position, 200 kg weight and 855 mm maximum height reach. Based on the identification using REBA in the mechanical posture after the design, it was found that the risk level decreased compared to before the design, from a high risk level to a low risk level. The results of the mechanical evaluation of the use of the designed motorcycle lift, there are several things that have become shortcomings of this design, among others, in terms of the speed of time in raising the position of the motorbike and the boot of the motorcycle lift which is still too heavy.Analisis struktur adalah ilmu yang menentukan pengaruh beban terhadap struktur fisik dan komponennya. Analisis struktural menggabungkan bidang mekanika teknik, teknik material, dan matematika teknik untuk menghitung deformasi struktur, gaya internal, tegangan, reaksi bantalan, percepatan, dan stabilitas. Perancang memilih perangkat lunak solidworks untuk desain dan analisis karena perangkat lunak ini dapat mensimulasikan desain dan kalkulasi gaya pada peralatan dan elemen mesin dengan baik. Solidworks berisi kumpulan program simulasi yang mudah digunakan dan dapat digunakan untuk membuat program part dan pemilihan material yang digunakan untuk analisa mekanik di tempat kerja guna mendapatkan faktor stress, displacement dan safety (keselamatan pabrik). Motorcycle lift yang dirancang memiliki rangka baja tahan karat krom dengan sistem kontrol, dengan dimensi utama panjang 1800 mm, lebar 700 mm dan tinggi 200 mm pada posisi minimum, berat 200 kg, dan tinggi maksimum jangkauan 855 mm. Berdasarkan hasil identifikasi menggunakan REBA pada postur mekanis setelah desain diketahui bahwa tingkat risiko mengalami penurunan dibandingkan sebelum desain, dari tingkat risiko tinggi ke tingkat risiko rendah. Hasil evaluasi mekanik terhadap penggunaan rancangan motorcycle lift terdapat beberapa hal yang menjadi kekurangan dari perancangan ini antara lain dari segi kecepatan waktu dalam menaikkan posisi sepeda motor dan booting yang masih terlalu berat

Distribution of endocrine cells in the gut of the impala (Aepyceros melampus)

Immunocytochemical methods were employed to demonstrate endocrine cells, containing peptides and serotonin, in the gut of the impala. Cells immunoreactive to serotonin, somatostatin, gastrin, cholecystokinin, glucagon, neurotensin, secretin, glucose-dependant insulinotropic peptide and motilin were detected. Antisera raised to substance P and pancreatic polypeptide failed to stain any cells. The distribution of these peptide-containing cells is more in line with the situation in sheep than other ruminants. In contrast, the distribution and abundance of serotonin cells in the gut of the impala parallels the situation seen in game herbivores.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat X Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

The KATRIN Pre-Spectrometer at reduced Filter Energy

The KArlsruhe TRItium Neutrino experiment, KATRIN, will determine the mass of the electron neutrino with a sensitivity of 0.2 eV (90% C.L.) via a measurement of the beta-spectrum of gaseous tritium near its endpoint of E_0 =18.57 keV. An ultra-low background of about b = 10 mHz is among the requirements to reach this sensitivity. In the KATRIN main beam-line two spectrometers of MAC-E filter type are used in a tandem configuration. This setup, however, produces a Penning trap which could lead to increased background. We have performed test measurements showing that the filter energy of the pre-spectrometer can be reduced by several keV in order to diminish this trap. These measurements were analyzed with the help of a complex computer simulation, modeling multiple electron reflections both from the detector and the photoelectric electron source used in our test setup.Comment: 22 pages, 12 figure

Excretion of alcelaphine herpesvirus-1 by captive and free-living wildebeest (Connochaetes taurinus)

Excretion of alcelaphine herpesvirus-1 (AHV-1) is for all practical purposes limited to wildebeest calves under the age of 4 months. Sixty-one per cent of calves 1-2 months of age excreted virus with a mean titre of 9,8 x 10⁴ cytopathic-forming foci/ml in their ocular fluid. The incidence declined sharply to less than 2% in wildebeest older than 6 months. No difference in age-related excretion of virus could be detected between free-living and captive wildebeest and no virus could be isolated from free-living pregnant wildebeest cows or from captive cows and their calves during the first 4 weeks after birth. The occurrence of wildebeest-derived malignant catarrhal fever (WD MCF) during spring, when wildebeest do not excrete virus, is a strong indication of the existence of an alternative host or an intermediate host capable of biological transfer of AHV-1.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu2014mn201

COMT val158met Polymorphism and Neural Pain Processing

A functional polymorphism (val158met) of the gene coding for Catechol-O-methyltransferase (COM) has been demonstrated to be related to processing of emotional stimuli. Also, this polymorphism has been found to be associated with pain regulation in healthy subjects. Therefore, we investigated a possible influence of this polymorphism on pain processing in healthy persons as well as in subjects with markedly reduced pain sensitivity in the context of Borderline Personality Disorder (BPD). Fifty females (25 patients with BPD and 25 healthy control participants) were included in this study. Genotype had a significant – though moderate - effect on pain sensitivity, but only in healthies. The number of val alleles was correlated with the BOLD response in several pain-processing brain regions, including dorsolateral prefrontal cortex, posterior parietal cortex, lateral globus pallidus, anterior and posterior insula. Within the subgroup of healthy participants, the number of val alleles was positively correlated with the BOLD response in posterior parietal, posterior cingulate, and dorsolateral prefrontal cortex. BPD patients revealed a positive correlation between the number of val alleles and BOLD signal in anterior and posterior insula. Thus, our data show that the val158met polymorphism in the COMT gene contributes significantly to inter-individual differences in neural pain processing: in healthy people, this polymorphism was more related to cognitive aspects of pain processing, whereas BPD patients with reduced pain sensitivity showed an association with activity in brain regions related to affective pain processing

The oesophagus and stomach of the African elephant : a histological, immunocytochemical and immunofluorescence study

Histological, immunocytochemical and immunofluorescence methods were employed to study the oesophagus and stomach of the elephant. The histological findings were in line with the situation in monogastric species like swine and man. In the mucosa of the stomach, endocrine cells were immunoreactive to gastrin, somatostatin, chromogranin A and serotonin. Nerve cells immunoreactive to somatostatin, bombesin, VIP, PHI and CGRP were detected in the submucosal and myenteric plexus of the stomach. In the stomach, the absence of glucagon cells and the presence of endocrine cells immunoreactive to PYY, are in contrast to the situation in mammals and need further investigation. Small gastric ulcers were observed in some of the specimens.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201