The Cryogenic AntiCoincidence detector for ATHENA X-IFU: a scientific assessment of the observational capabilities in the hard X-ray band

ATHENA is a large X-ray observatory, planned to be launched by ESA in 2028 towards an L2 orbit. One of the two instruments of the payload is the X-IFU: a cryogenic spectrometer based on a large array of TES microcalorimeters, able to perform integral field spectrography in the 0.2-12 keV band (2.5 eV FWHM at 6 keV). The X-IFU sensitivity is highly degraded by the particle background expected in the L2 orbit, which is induced by primary protons of both galactic and solar origin, and mostly by secondary electrons. To reduce the particle background level and enable the mission science goals, the instrument incorporates a Cryogenic AntiCoincidence detector (CryoAC). It is a 4 pixel TES based detector, placed <1 mm below the main array. In this paper we report a scientific assessment of the CryoAC observational capabilities in the hard X-ray band (E>10 keV). The aim of the study has been to understand if the present detector design can be improved in order to enlarge the X-IFU scientific capability on an energy band wider than the TES array. This is beyond the CryoAC baseline, being this instrument aimed to operate as anticoincidence particle detector and not conceived to perform X-ray observations.Comment: Accepted for publication on Experimental Astronom

Development of High Precision Timing Counter Based on Plastic Scintillator with SiPM Readout

High-time-resolution counters based on plastic scintillator with silicon photomultiplier (SiPM) readout have been developed for applications to high energy physics experiments for which relatively large-sized counters are required. We have studied counter sizes up to $120\times40\times5$ mm^3 with series connection of multiple SiPMs to increase the sensitive area and thus achieve better time resolution. A readout scheme with analog shaping and digital waveform analysis is optimized to achieve the highest time resolution. The timing performance is measured using electrons from a Sr-90 radioactive source, comparing different scintillators, counter dimensions, and types of near-ultraviolet sensitive SiPMs. As a result, a resolution of $\sigma =42 \pm 2$ ps at 1 MeV energy deposition is obtained for counter size $60\times 30 \times 5$ mm^3 with three SiPMs ($3\times3$ mm^2 each) at each end of the scintillator. The time resolution improves with the number of photons detected by the SiPMs. The SiPMs from Hamamatsu Photonics give the best time resolution because of their high photon detection efficiency in the near-ultraviolet region. Further improvement is possible by increasing the number of SiPMs attached to the scintillator.Comment: 11 pages, 17 figures, accepted by IEEE Trans. Nucl. Sc

Detailed design requirements of the TES spectrometer

This document is not to be reproduced, modified, adapted, republished, translated in any material form in whole or in part without the prior written permission of the authors.This document reports the set of requirements for the design and construction of the TES X-ray spectrometer prototype to be realized in the frame of the AHEAD2020 project WP15. These requirements have been identified, discussed and agreed by the WP15 partecipants during a series of meeting from the project start. For the main scientific requirements a verification method is proposed within this document to provide a guide for the test and integration phase. The document also shows some design implementation details with the purpose of better describe what the requirements are aimed to

The mechanical and EM simulations of the CryoAC for the ATHENA X-IFU

The design phase of the CryoAC DM for the ATHENA X-IFU has concerned numerical simulations to exploit different fabrication possibilities. The mechanical simulations have accounted for the peculiar detector structure: 4 silicon chips asymmetrically suspended by means of 4 microbridges each. A preliminary study was performed to analyze the response to acceleration spectra in the frequency domain, shocks and time domain random displacement, prior to a real vibration test campaign. EM simulations to spot unwanted magnetic fields have been conducted as well. In this work we will show the latest advance in the design of the new detectors, showing the main results coming from various simulations

Analysis of isometric strength and force-velocity relationship after 7 weeks of stable and unstable training on partial push up

Training with instability device seems to have useful adaptaments, but not all the autor confirm it. Instability training shows increase muscle activation due to the needed for stabilization. The increased stress associated with instability training has been postulated to promote greater neuromuscular adaptations, such as decreased co-contractions, improved intra and inter-coordination and set a lower stress on joint and muscle that can beneficial for musculoskeletal healt and rehabilitation. The aim of the research was to find the difference related in strength gain between an exercise under stable and unstable condition. Two groups of healty-fitness people follow a 7 weeks of stable and unstable training on partial push-up. The control group (CG) (n = 4, one female and three males, 25.0 ± 3.9 y) performed the push-up with hands on the floor, while the sperimental group (SG) (n = 7, two females and five males, 24.6 ± 2.3 y) performed push-up with hands on a Swissball. The execution time, the total volume and the articular ROM were standardized. The tests were: (1) a standardized isometric chest press and (2) force-velocity relationship of the chest muscle. For statistical analysis has been used the Wilcoxon matched-pairs signed rank test. The isometric strength has a positive correlation with the instability training (p 0.05). Instability training seems to show best adaptations on isometric strength, probably due to neural adaptations, while it seems that it doesn’t happen in force-velocity relationship, probably due to the standardized time of execution

MARE-1 in Milan: Status and Perspectives

The international project MARE (Microcalorimeter Array for a Rhenium Experiment) aims at the direct and calorimetric measurement of the electron neutrino mass with sub-eV sensitivity. Although the baseline of the MARE project consists in a large array of rhenium based thermal detectors, a different option for the isotope is also being considered. The different option is 163Ho. The potential of using 187Re for a calorimetric neutrino mass experiment has been already demonstrated. On the contrary, no calorimetric spectrum of 163Ho has been so far measured with the precision required to set a useful limit on the neutrino mass. The first phase of the project (MARE-1) is a collection of activities with the aim of sorting out both the best isotope and the most suited detector technology to be used for the final experiment. One of the MARE-1 activities is carried out in Milan by the group of Milano–Bicocca in collaboration with NASA/GSFC and Wisconsin groups. The Milan MARE-1 arrays are based on semiconductor thermistors, provided by the NASA/GSFC group, with dielectric silver perrhenate absorbers, AgReO4. The experiment, which is presently being assembled, is designed to host up to 8 arrays. With 288 detectors, a sensitivity of 3 eV at 90% CL on the neutrino mass can be reached within 3 years. This contribution gives an outlook for the MARE activities for the active isotope selection. In this contribution the status and the perspectives of the MARE-1 in Milan are also reported

Stability, Crystal Chemistry, and Magnetism of U2+xNi21–xB6 and Nb3–yNi20+yB6 and the Role of Uranium in the Formation of the Quaternary U2–zNbzNi21B6 and UδNb3−δNi20B6 Systems

We investigated the U–Ni–B and Nb–Ni–B systems to search for possible new heavy fermion compounds and superconducting materials. The formation, crystal chemistry, and physical properties of U2Ni21B6 and Nb3–yNi20+yB6 [ternary derivatives of the cubic Cr23C6-type (cF116, Fm3̅m)] have been studied; the formation of the hypothetical “U3Ni20B6” and “Nb2Ni21B6” has been disproved. U2Ni21B6 [a = 10.6701(2) Å] crystallizes in the ordered W2Cr21C6-type, whereas Nb3–yNi20+yB6 [a = 10.5842(1) Å] adopts the Mg3Ni20B6-type. Ni in U2Ni21B6 can be substituted by U, leading to the solid solution U2+xNi21–xB6 (0 ≤ x ≤ 0.3); oppositely, Nb in Nb3Ni20B6 is partially replaced by Ni, forming the solution Nb3–yNi20+yB6 (0 ≤ y ≤ 0.5), none of them reaching the limit corresponding to the hypothetically ordered “U3Ni20B6” and “Nb2Ni21B6”. These results prompted us to investigate quaternary compounds U2–zNbzNi21B6 and UδNb3−δNi20B6: strong competition in the occupancy of the 4a and 8c sites by U, Nb, and Ni atoms has been observed, with the 4a site occupied by U/Ni atoms only and the 8c site filled by U/Nb atoms only. U2Ni21B6, U2.3Ni20.7B6, and Nb3Ni20B6 are Pauli paramagnets. Interestingly, Nb2.5Ni20.5B6 shows ferromagnetism with TC ≈ 11 K; the Curie–Weiss fit gives an effective magnetic moment of 2.78 μB/Ni, suggesting that all Ni atoms in the formula unit contribute to the total magnetic moment. The M(H) data at 2 K further corroborate the ferromagnetic behavior with a saturation moment of 10 μB/fu (≈0.49 μB/Ni). The magnetic moment of Ni at the 4a site induces a moment in all of the Ni atoms of the whole unit cell (32f and 48h sites), with all atoms ordering ferromagnetically at 11 K. Density functional theory (DFT) shows that the formation of U2Ni21B6 and Nb3Ni20B6 is energetically preferred. The various electronic states generating ferromagnetism on Nb2.5Ni20.5B6 and Pauli paramagnetism on U2Ni21B6 and Nb3Ni20B6 have been identified

Does Student Orientation Improve Nursing Image and Positively Influence the Enrolment of Nursing Students in the University? An Observational Study

Background and aim of the study: Nursing has not yet received full social recognition and in general the public opinion does not have a completely positive perception of it, which regards it as an auxiliary profession to the medical profession. This study aims to investigate the image of the nurse among year 4 and 5 high school students. Methods: Two groups of students were interviewed, one at their institution without any previous orientation (n = 102) and one at the University of Bologna during orientation day (n = 388). A validated questionnaire (Nursing Attitude Questionnaire) of 30 items was delivered. Two additional questions were added to explore the possibility of advising relatives and acquaintances to become a nurse and therefore to choose the nursing degree course. Results: All areas of the NAQ scored significantly higher in the group where students attended the orientation day, especially the ones related to the professional role, stereotypes and professional value items. Female students ≥ 21 had a more positive image of the nurse. Both groups recognized that nurses are important figures for patients and that they are intelligent people, who must have a degree in order to carry out their work duties. Differences between the groups were recorded. Students in group 1 did not accept nursing autonomy while students in group 2 understood differences between nursing and medical careers, attributing to them the same value. A positive correlation between the positive image of the nursing profession and the interest in becoming nurses or advising others to undertake the nursing course was found. In conclusion, orientation is effective in helping high school students in the choice of their university courses. Regarding nursing, strategies to improve the image of the nurse and enrollment should be combined during orientation day with current up to date communication and learning tools, such as social media and simulation laboratories. Furthermore, it appears increasingly important to extend orientation and tutoring activities to junior high school students, families and teachers