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

LGBT+ Training needs for health and social care professionals: a cross-cultural comparison among seven European countries

Introduction Research suggests that specific training on LGBT+ issues may improve the competencies and skills of health and social care (HSC) professionals, which reduces the negative attitudes toward LGBT+ people. Despite this, there seems to be a lack of coverage of LGBT+ needs in HSC education. The present study aims to explore the specific LGBT+ training needs of HSC professionals and to examine the relationship between these training needs and the four dimensions of the Papadopoulos model, i.e. cultural awareness, cultural knowledge, cultural sensitivity, and cultural competence. Methods The research used data from a cross-cultural project, “Intercultural Education for Nurses in Europe (IENE9),” which was administered to 412 HSC academics and workers (62% females; Mage=46.06, SDage=10.48) between February 2020 and July 2020, in seven European countries: UK (coordinator), Denmark, Spain, Germany, Cyprus, Italy, and Romania. Results Hierarchical multiple regression showed that higher training needs were associated with cultural awareness, cultural knowledge, and cultural competence. The need for training on LGBT+ issues was higher for Cyprus, Romania, Spain, Italy, and the UK, compared with Denmark (no differences between Germany and Denmark were found). Conclusions We believe that there has been a lack of focus on the LGBT+ training needs of HSC professionals: Greater efforts are required to develop a culturally competent and compassionate LGBT+ curriculum. Social Policy Implications Findings from the present study will inform the development of a free, Massive Open Online Course (MOOC), for culturally competent and compassionate HSC professionals in Europe to improve the quality of their car

Remarks on the Configuration Space Approach to Spin-Statistics

The angular momentum operators for a system of two spin-zero indistinguishable particles are constructed, using Isham's Canonical Group Quantization method. This mathematically rigorous method provides a hint at the correct definition of (total) angular momentum operators, for arbitrary spin, in a system of indistinguishable particles. The connection with other configuration space approaches to spin-statistics is discussed, as well as the relevance of the obtained results in view of a possible alternative proof of the spin-statistics theorem.Comment: 18 page

Could Only Fermions Be Elementary?

In standard Poincare and anti de Sitter SO(2,3) invariant theories, antiparticles are related to negative energy solutions of covariant equations while independent positive energy unitary irreducible representations (UIRs) of the symmetry group are used for describing both a particle and its antiparticle. Such an approach cannot be applied in de Sitter SO(1,4) invariant theory. We argue that it would be more natural to require that (*) one UIR should describe a particle and its antiparticle simultaneously. This would automatically explain the existence of antiparticles and show that a particle and its antiparticle are different states of the same object. If (*) is adopted then among the above groups only the SO(1,4) one can be a candidate for constructing elementary particle theory. It is shown that UIRs of the SO(1,4) group can be interpreted in the framework of (*) and cannot be interpreted in the standard way. By quantizing such UIRs and requiring that the energy should be positive in the Poincare approximation, we conclude that i) elementary particles can be only fermions. It is also shown that ii) C invariance is not exact even in the free massive theory and iii) elementary particles cannot be neutral. This gives a natural explanation of the fact that all observed neutral states are bosons.Comment: The paper is considerably revised and the following results are added: in the SO(1,4) invariant theory i) the C invariance is not exact even for free massive particles; ii) neutral particles cannot be elementar

Commissioning of the vacuum system of the KATRIN Main Spectrometer

The KATRIN experiment will probe the neutrino mass by measuring the beta-electron energy spectrum near the endpoint of tritium beta-decay. An integral energy analysis will be performed by an electro-static spectrometer (Main Spectrometer), an ultra-high vacuum vessel with a length of 23.2 m, a volume of 1240 m^3, and a complex inner electrode system with about 120000 individual parts. The strong magnetic field that guides the beta-electrons is provided by super-conducting solenoids at both ends of the spectrometer. Its influence on turbo-molecular pumps and vacuum gauges had to be considered. A system consisting of 6 turbo-molecular pumps and 3 km of non-evaporable getter strips has been deployed and was tested during the commissioning of the spectrometer. In this paper the configuration, the commissioning with bake-out at 300{\deg}C, and the performance of this system are presented in detail. The vacuum system has to maintain a pressure in the 10^{-11} mbar range. It is demonstrated that the performance of the system is already close to these stringent functional requirements for the KATRIN experiment, which will start at the end of 2016.Comment: submitted for publication in JINST, 39 pages, 15 figure

Socially assistive robots in health and social care: acceptance and cultural factors. Results from an exploratory international online survey

Aim: This study explored the views of an international sample of registered nurses and midwives working in health and social care concerning socially assistive robots (SARs), and the relationship between dimensions of culture and rejection of the idea that SARs had benefits in these settings. Methods: An online survey was used to obtain rankings of (among other topics) the extent to which SARs have benefits for health and social care. It also asked for free text responses regarding any concerns about SARs. Results: Most respondents were overwhelmingly positive about SARs' benefits. A small minority strongly rejected this idea, and qualitative analysis of the objections raised by them revealed three major themes: things might go wrong, depersonalization, and patient‐related concerns. However, many participants who were highly accepting of the benefits of SARs expressed similar objections. Cultural dimensions of long‐term orientation and uncertainty avoidance feature prominently in technology acceptance research. Therefore, the relationship between the proportion of respondents from each country who felt that SARs had no benefits and each country's ratings on long‐term orientation and uncertainty avoidance were also examined. A significant positive correlation was found for long‐term orientation, but not for uncertainty avoidance. Conclusion: Most respondents were positive about the benefits of SARs, and similar concerns about their use were expressed both by those who strongly accepted the idea that they had benefits and those who did not. Some evidence was found to suggest that cultural factors were related to rejecting the idea that SARs had benefits

Reduction of stored-particle background by a magnetic pulse method at the KATRIN experiment

The KATRIN experiment aims to determine the effective electron neutrino mass with a sensitivity of 0.2 eV/c2 (%90 CL) by 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. A common background source in this setup is the decay of short-lived isotopes, such as 219Rn and 220Rn, in the spectrometer volume. Active and passive countermeasures have been implemented and tested at the KATRIN main spectrometer. One of these is the magnetic pulse method, which employs the existing air coil system to reduce the magnetic guiding field in the spectrometer on a short timescale in order to remove low- and high-energy stored electrons. Here we describe the working principle of this method and present results from commissioning measurements at the main spectrometer. Simulations with the particle-tracking software Kassiopeia were carried out to gain a detailed understanding of the electron storage conditions and removal processes

Reduction of stored-particle background by a magnetic pulse method at the KATRIN experiment

The KATRIN experiment aims to determine the effective electron neutrino mass with a sensitivity of 0.2 eV/c2 (%90 CL) by 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. A common background source in this setup is the decay of short-lived isotopes, such as 219Rn and 220Rn, in the spectrometer volume. Active and passive countermeasures have been implemented and tested at the KATRIN main spectrometer. One of these is the magnetic pulse method, which employs the existing air coil system to reduce the magnetic guiding field in the spectrometer on a short timescale in order to remove low- and high-energy stored electrons. Here we describe the working principle of this method and present results from commissioning measurements at the main spectrometer. Simulations with the particle-tracking software Kassiopeia were carried out to gain a detailed understanding of the electron storage conditions and removal processes