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- Apponi, A., et al.
(author)
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Heisenberg's uncertainty principle in the PTOLEMY project : A theory update
- 2022
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In: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 106:5
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Journal article (peer-reviewed)abstract
- We discuss the consequences of the quantum uncertainty on the spectrum of the electron emitted by the beta-processes of a tritium atom bound to a graphene sheet. We analyze quantitatively the issue recently raised by Cheipesh, Cheianov, and Boyarsky [Phys. Rev. D 104, 116004 (2021)], and discuss the relevant timescales and the degrees of freedom that can contribute to the intrinsic spread in the electron energy. We perform careful calculations of the potential between tritium and graphene with different coverages and geometries. With this at hand, we propose possible avenues to mitigate the effect of the quantum uncertainty.
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| 2. |
- Betti, M. G., et al.
(author)
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A design for an electromagnetic filter for precision energy measurements at the tritium endpoint
- 2019
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In: Progress in Particle and Nuclear Physics. - : Elsevier BV. - 0146-6410 .- 1873-2224. ; 106, s. 120-131
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Research review (peer-reviewed)abstract
- We present a detailed description of the electromagnetic filter for the PTOLEMY project to directly detect the Cosmic Neutrino Background (CNB). Starting with an initial estimate for the orbital magnetic moment, the higher-order drift process of E x B is configured to balance the gradient-B drift motion of the electron in such a way as to guide the trajectory into the standing voltage potential along the mid-plane of the filter. As a function of drift distance along the length of the filter, the filter zooms in with exponentially increasing precision on the transverse velocity component of the electron kinetic energy. This yields a linear dimension for the total filter length that is exceptionally compact compared to previous techniques for electromagnetic filtering. The parallel velocity component of the electron kinetic energy oscillates in an electrostatic harmonic trap as the electron drifts along the length of the filter. An analysis of the phase-space volume conservation validates the expected behavior of the filter from the adiabatic invariance of the orbital magnetic moment and energy conservation following Liouville's theorem for Hamiltonian systems.
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| 3. |
- Apponi, A., et al.
(author)
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Implementation and optimization of the PTOLEMY transverse drift electromagnetic filter
- 2022
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In: Journal of Instrumentation. - : IOP Publishing Ltd. - 1748-0221. ; 17:5
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Journal article (peer-reviewed)abstract
- The PTOLEMY transverse drift filter is a new concept to enable precision analysis of the energy spectrum of electrons near the tritium beta-decay endpoint. This paper details the implementation and optimization methods for successful operation of the filter for electrons with a known pitch angle. We present the first demonstrator that produces the required magnetic field properties with an iron return-flux magnet. Two methods for the setting of filter electrode voltages are detailed. The challenges of low-energy electron transport in cases of low field are discussed, such as the growth of the cyclotron radius with decreasing magnetic field, which puts a ceiling on filter performance relative to fixed filter dimensions. Additionally, low pitch angle trajectories are dominated by motion parallel to the magnetic field lines and introduce non-adiabatic conditions and curvature drift. To minimize these effects and maximize electron acceptance into the filter, we present a three-potential-well design to simultaneously drain the parallel and transverse kinetic energies throughout the length of the filter. These optimizations are shown, in simulation, to achieve low-energy electron transport from a 1 T iron core (or 3 T superconducting) starting field with initial kinetic energy of 18.6 keV drained to < 10 eV (< 1 eV) in about 80 cm. This result for low field operation paves the way for the first demonstrator of the PTOLEMY spectrometer for measurement of electrons near the tritium endpoint to be constructed at the Gran Sasso National Laboratory (LNGS) in Italy.
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| 10. |
- Nyberg, L., et al.
(author)
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Observational study of tofacitinib in Ulcerative Colitis in Sweden (ODEN) - Interim analysis of health-related quality of life and fatigue
- 2024
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In: Journal of Crohn's & Colitis. - : Oxford University Press. - 1873-9946 .- 1876-4479. ; 18:Suppl. 1, s. I1887-I1889
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Journal article (other academic/artistic)abstract
- Background: Ulcerative colitis (UC) has a major impact on daily life. The Janus Kinas (JAK) inhibitor tofacitinib is effective in achieving remission in UC, but prospective real-world evidence concerning the effect on health-related quality of life (HRQoL) and fatigue are still scarce. Fatigue is a component of UC that is notoriously difficult to treat and not unambiguously related to inflammatory activity. ODEN is an ongoing Swedish multicentre prospective observational study of tofacitinib in UC. In this interim analysis, we assessed the effectiveness on HRQoL and fatigue during the first 16 weeks.Methods: Patients with UC and active inflammation were enrolled 2020-2023 when starting tofacitinib as per clinical indication. To measure various aspects of impairment of daily life, the validated questionnaires Short Health Scale (SHS), EQ-5D-5L [Swedish value set], and IBD-fatigue scale (IBD-F) were used. These data and information concerning clinical, biochemical, and endoscopic outcomes were collected in an e-CRF linked to the Swedish National Quality Registry for Inflammatory Bowel Disease (SWIBREG). For HRQoL outcomes, per protocol analysis was applied. Paired t-test and Wilcoxon’s signed-rank test were used for mean and median differences, respectively.Results: In total, 103 patients were included. Baseline data are shown in Table 1a. For patients still on tofacitinib treatment, all four dimensions of the SHS (symptoms, social function, disease related worry, and general well-being) improved significantly, Table 1b. A median decrease of one point from baseline was seen at week 8 in each of the parameters, which was maintained through week 16 with a tendency towards further improvement. EQ-5D-5L showed an impairment mainly in the aspects of pain/discomfort and ability to participate in common daily activities. Improvement in these dimensions was seen from baseline to week 16. The overall EQ-5D-5L index improved significantly from baseline (0.80) to week 8 (0.86) and week 16 (0.89), as did the EQ VAS 0-100 reflecting overall health (58, 71, and 74, respectively). A significant improvement in IBD-F part 1 and 2 was seen at week 8 and 16, Figure 1.Conclusion: This study demonstrates that tofacitinib treatment covariates with positive changes in a variety of measures of patients’ quality of life, including improvements in self-assessed overall wellbeing. Finally, fatigue significantly improved during tofacitinib treatment. Thus, tofacitinib treatment shows association with meaningful improvements in multiple aspects of quality of life during the first 16 weeks of treatment.
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