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PurposeThe main purpose of this paper is to assess the patterns in the public discourse of successful chief executive officers (CEOs) in terms of performance, with the CEO's strengths and aspects to improve.Design/methodology/approachThis paper aligns with the literature that appraises CEO public discourse and relevance. From the literature review, the strategic levers in CEO discourse toward high performance are identified. The CEO letters in the period 2017–2019 of the top 25 best performing CEOs (BPCs) according to Harvard Business Review ranking 2019 are qualitatively examined through a multiple close reading analytical technique and multiple correspondence analysis (MCA) is applied to assess the patterns.FindingsThe paper delivers a three-dimensional model representing how the identified strategic levers are articulated by BPCs in the BPC's discourse following diverse patterns. This paper points out BPC's strengths, among them a high level of moral reasoning compared to previous studies and improvable areas such as the extended absence of autocritique at the firm and personal level or the lack of leverage on the need for agility and proactive adaption.Practical implicationsThis paper contributes further CEO awareness of the strategic role of the discourse and offers clues to enhance CEO awareness, as well as criteria for boards of directors to appraise CEO discourse.Originality/valueAdopting a novel approach, this paper addresses the strategic levers triggered by CEOs in their letters from a managerial implication perspective, providing relevant theoretical insight on how they are articulated.

The fashion industry has been driven by limitless consumption-led growth spearheaded by companies in the fast fashion segment, with a dominant business model based on massive accelerated demand, production, consumption, and disposal. Despite companies’ efforts to decouple the pursuit of growth from its negative impacts, a more sufficiency-driven approach seems imperative to curb consumerism and contribute more effectively to sustainability. This study draws on the literature to build a three-pillar framework of potential strategies to enable fashion companies to foster sufficient consumption and reduce dependence on the sale of new items, with benefits expected for both consumers and companies. Subsequently, it uses multiple case study to examine qualitatively the annual reports issued during 2013–2014 and 2020–2021 by a sample of ten top companies in this segment. The goal is to assess whether these companies are embracing such strategies, what (if any) evolution occurs between these two periods, whether the 2030 Agenda with its SDG12 ‘Responsible consumption and production’ plays a mediating role in their adoption, and what is the logic behind such evolution. The results show that, although such adoption is gaining momentum, companies tend first to embrace strategies with less impact on their traditional modus operandi. Further, the laxity of SDG12 enables companies to profess commitment even when not addressing any of the strategies to foster sufficient consumption. This study aims to give actors critical awareness of this issue and provide practical guidance for managers to adopt and combine these strategies decisively to fully embrace the principles of circular economy and a more holistic approach to sustainability. It also advises companies to avoid the risk of ‘anti-consumerist washing’—a newly identified variant of greenwashing—and proposes to study a ‘hierarchical pyramid of business strategies to rationalize consumption, Ministry of Science and Innovation of the Government of Spain PDI2021.124396NB.I00, European Regional Development Fund (European Union), CRUE-Universitat Politecnica de Valencia

Este trabalho é um recorte de pesquisa de Mestrado realizada no âmbito do Programa de Pós-graduação em Letras da Universidade Federal do Amazonas, baseado em investigação bibliográfica e documental de cunho quali-quantitativo, que tem como corpora o Edital de Convocação para o Processo de Inscrição e Avaliação para o PNLD 2018 LEM Espanhol e a coleção Cercanía Joven. Para este artigo, apresentamos resultados sobre a abordagem destinada às Tecnologias da Informação e da Comunicação (TIC) nos documentos que compõem a pesquisa, justificada pelo fato de a BNCC para o ensino médio, aprovada em 2018, colocar em evidência as Tecnologias da Informação e da Comunicação – TIC, recomendando sua aplicação no processo de ensino-aprendizagem, além da relação entre as TIC e o cotidiano da sala de aula. Os principais investigadores que embasam este trabalho são Mantovani (2009), Galan e Teixeira (2012), Galan (2016), Teixeira (2017 e 2018), e Barros, Marins-Costa e Freitas (2018). Os resultados preliminares apontam que o edital PNLD 2018 apresenta alguns critérios que podem ser efetivados por meio das TIC, apesar de não mencionar explicitamente o uso desses recursos tecnológicos e que, além disso, na coleção avaliada, há pouca variedade nas propostas de utilização dos recursos tecnológicos, predominância de práticas orientadas a serem realizadas fora de sala de aula, progressão nos níveis de dificuldade das propostas por meio das TIC e, também, a predominância de atividades que utilizam CD.

Dark Matter searches have been ongoing for three decades; the lack of a positive discovery of the main candidate, the WIMP, after dedicated efforts, has put axions and axion-like-particles in the spotlight. The three main techniques employed to search for them complement each other well in covering a wide range in the parameter space defined by the axion decay constant and the axion mass. The International AXion Observatory (IAXO) is an international collaboration planning to build the fourth generation axion helioscope, with an unparalleled expected sensitivity and discovery potential. The distinguishing characteristic of IAXO is that it will feature an axion-specific magnet, with a large axion-sensitive cross-section, and will be equipped with x-ray focusing devices and detectors that have been developed for axion physics. In this paper, we review aspects that motivate IAXO and its prototype, BabyIAXO, in the axion and ALPs landscape. As part of this Special Issue, some emphasis is given on the Spanish participation in the project, of which CAPA is a strong promoter, 21 pages, 5 figures. Submitted to Universe

To determine the extent to which Black race is associated with the infant mortality rate ( 365 day, IMR) of births to US-born and foreign-born Latinx women.Stratified and multivariable binominal log-linear regression analyses were performed on the 2010-2013 National Center for Health Statistics linked birth-death certificate files of singleton infants.The IMR of births to US-born Black Latinx women (N = 54,542) exceeded that of births to US-born White Latinx women (N = 1,320,084): 5.7/1000 vs 4.2/1000, RR = 1.4 (1.2, 1.5). In contrast, the IMR of births to foreign-born Black Latinx women (N = 35,544) approximated that of births to foreign-born White Latinx women (N = 1,372,172): 3.8/1000 vs 3.6/1000, RR = 1.0 (0.9, 1.2) The adjusted (controlling for maternal age, education, prenatal care, high parity, and region of residence) RR of infant mortality for births to US-born and foreign-born Black (versus non-Latinx White) Latinx women equaled 1.4 (1.2, 1.6) and 1.0 (0.8, 1.2), respectively. The adjusted RR of infant mortality for births to US-born and foreign-born White (versus non-Latinx White) Latinx women equaled 1.0 (0.9, 1.0) and 0.8 (0.7, 0.8), respectively.Black race is associated with a 1.4-fold higher IMR among births to US-born Latinx women. A similar phenomenon does not occur among foreign-born Latinx women. These intriguing findings highlight that the social construct of Black race across the life-course of Latinx women are detrimental to infant outcome.

The European physical journal / C 82(2), 120 (2022). doi:10.1140/epjc/s10052-022-10061-1, A finite axion-nucleon coupling, nearly unavoidable for QCD axions, leads to the production of axions via the thermal excitation and subsequent de-excitation of Fe-57 isotopes in the sun. We revise the solar bound on this flux adopting the up to date emission rate, and investigate the sensitivity of the proposed International Axion Observatory IAXO and its intermediate stage BabyIAXO to detect these axions. We compare different realistic experimental options and discuss the model dependence of the signal. Already BabyIAXO has sensitivity far beyond previous solar axion searches via the nucleon coupling and IAXO can improve on this by more than an order of magnitude., Published by Springer, Heidelberg

[EN] This paper analyzes the characteristics of the students that promote greater or less emotional involvement in a context of postgraduate teaching in the field of industry. In particular, professional experience, previous training in the subject, learning motivations, previous experiences in blended learning, age and sex are considered. For such a purpose, feedback from the students (N = 74) is obtained through a Likert scale survey. The results show that professional experience in the sector and previous training, as well as learning motivations, are the ones that significantly condition the emotional involvement of students in this context., [ES] En este artículo se analizan las características del alumnado que propician una mayor o menor involucración emocional en un contexto de enseñanza semipresencial de posgrado en el ámbito de la industria. En particular se consideran la experiencia profesional, la formación previa en la materia, motivaciones de aprendizaje, experiencias previas en docencia semipresencial, edad y sexo. Para ello se obtiene un feedback del alumnado (N=74) mediante una encuesta con escala de Likert. Los resultados muestran que la experiencia profesional en el sector y la formación previa, así como las motivaciones de aprendizaje son las que condicionan de forma significativa la involucración emocional del alumnado en este contexto.

[EN] The University Part-time Assistant Professor is called to contribute with his experience to the balance between theory and practice and to achieve a greater connection between the academic world and the labor and social world. However, there is a controversy regarding the use given to this figure, which already represents more than 20% of university professors in Spain. Despite this, there is a paucity of publications that focus on strategies to improve their performance. Starting from the consulted publications, which are part of our theorical framework of reference, this article carries out a critical and constructive analysis of possible strategies and innovative proposals for improving the performance of this group, in order to promote discussion among the academics in this field., [ES] El Profesor Asociado universitario está llamado a contribuir con su experiencia al equilibrio entre teoría y práctica y a conseguir una mayor conexión entre el mundo académico y el laboral y social. Sin embargo, existe una controversia en torno al uso que se da a esta figura, que supone ya más del 20% de los docentes universitarios en España. A pesar de ello, hay una escasez de publicaciones que se centren en las estrategias para mejorar su desempeño. A partir de la experiencia de los autores y con el apoyo de la literatura, este artículo lleva a cabo un análisis crítico y constructivo de posibles estrategias y propuestas innovadoras para la mejora del desempeño de este colectivo, con el objeto de promover la discusión entre los académicos en este ámbito.

The Sun is a well-studied astrophysical source of axion-like particles (ALPs), produced mainly through the Primakoff process. Moreover, in the Sun there exist large-scale magnetic fields that catalyze an additional ALP production via a coherent conversion of thermal photons. We study this contribution to the solar ALP emissivity, typically neglected in previous investigations. Furthermore, we discuss additional bounds on the ALP-photon coupling from energy-loss arguments, and the detection perspectives of this new ALP flux at future helioscope and dark matter experiments., v2: 15 pages, 7 pdf figures. Figures improved, typos removed. Matches the version published on PRD

Axions are a natural consequence of the Peccei-Quinn mechanism, the most compelling solution to the strong-CP problem. Similar axion-like particles (ALPs) also appear in a number of possible extensions of the Standard Model, notably in string theories. Both axions and ALPs are very well motivated candidates for Dark Matter, and in addition, they would be copiously produced at the sun's core. A relevant effort during the last decade has been the CAST experiment at CERN, the most sensitive axion helioscope to-date. The International Axion Observatory (IAXO) is a large-scale 4th generation helioscope. As its primary physics goal, IAXO will look for solar axions or ALPs with a signal to background ratio of about 5 orders of magnitude higher than CAST. Recently the IAXO collaboration has proposed and intermediate experimental stage, BabyIAXO, conceived to test all IAXO subsystems (magnet, optics, detectors and sun-tracking systems) at a relevant scale for the final system and thus serve as pathfinder for IAXO but at the same time as a fully-fledged helioscope with record and relevant physics reach in itself with potential for discovery. BabyIAXO was endorsed by the Physics Review committee of DESY last May 2019. Here we will review the status and prospects of BabyIAXO and its potential to probe the most physics motivated regions of the axion & ALPs parameter space., 6 pages, ICHEP 2020 Virtual conference

TREX-DM (TPC Rare Event eXperiment for Dark Matter) is a high-pressure Micromegas-based TPC designed to host a few hundreds of grams of light nuclei (argon or neon) with energy thresholds potentially at the level of 0.4 keVee or below. Preliminary background studies suggest that the levels expected are of the order of 1–10 counts keV−1 kg−1 d−1, making TREX-DM competitive in the search for low mass WIMPs (

A novel large volume spherical proportional counter, recently developed, is used for neutron measurements. The pure N2 gas is studied for thermal and fast neutron detection, providing a new way for neutron spectroscopy. The neutrons are detected via the N 14 ( n , p ) C 14 and N 14 ( n , α ) B 11 reactions. The detector is tested for thermal and fast neutrons detection with Cf 252 and Am 241 − Be 9 neutron sources. The atmospheric neutrons are successfully measured from thermal up to several MeV, well separated from the cosmic ray background. A comparison of the spherical proportional counter with the current available neutron counters is also presented.

O presente artigo apresenta pesquisa sobre a abordagem destinada às Tecnologias da Informação e da Comunicação (TIC) em livro didático para o ensino de Espanhol aprovado no âmbito do Programa Nacional do Livro Didático (PNLD) 2018. Trata-se de um recorte de investigação de Mestrado desenvolvida no Amazonas, baseada em pesquisa bibliográfica e documental, que tem como corpora o livro didático e o Edital de Convocação para o Processo de Inscrição e Avaliação para o PNLD 2018. Os principais teóricos que embasam a pesquisa e este artigo são AUTOR (2010, 2018), Moran, Masseto e Behrens (2012) e Guimarães e Freitas (2018). Os resultados preliminares apontam que o Edital PNLD 2018 apresenta critérios que podem ser efetivados por meio das TIC, apesar de não mencionarem explicitamente o uso desses recursos tecnológicos e, além disso, pouca variedade nas propostas didático-pedagógicas no livro didático investigado, com predominância para TIC que amparam atividades de compreensão auditiva. Constatamos, também, uma preocupante perspectiva sobre a manutenção do componente de Língua Espanhola no âmbito do PNLD.

The T-REX project of the group of the University of Zaragoza includes a number of R&D and prototyping activities to explore the applicability of gaseous Time Projection Chambers (TPCs) with Micromesh Gas Structures (Micromegas) in rare event searches where the pattern recognition of the signal is crucial for background discrimination. In the CAST experiment (CERN Axion Solar Telescope) a background level as low as 0.8 × 10−6 counts keV−1 cm−2 s−1 was achieved. Prototyping and simulations promise a 105 better signal-to-noise ratio than CAST for the future IAXO (International Axion Observatory) using x-ray telescopes. A new strategy is also explored in the search of WIMPS based on high gas pressure: the TREX-DM experiment, a low energy threshold detector. In both cases, axion and WIMP searches, the image of the expected signal is quite simple: a one cluster deposition coming from the magnet bore in the case of axions and, if possible, with a tadpole form in the case of WIMPs. It is the case of double beta decay (DBD) where imaging and pattern recognition play a major role. Results obtained in Xe + trimethylamine (TMA) mixture point to a reduction in electron diffusion which improves the quality of the topological pattern, with a positive impact on the discrimination capability, as shown in TREX-ββ prototype. Microbulk Micromegas are able to image the DBD ionization signature with high quality while, at the same time, measuring its energy deposition with a resolution of at least a ~ 3% FWHM at the transition energy Qββ and even better (up to ~ 1% FWHM) as extrapolated from low energy events. That makes Micromegas-based HPXe TPC a very competitive technique for the next generation DBD experiments (as PANDAX-III). Here, it will be shown the last results of the TREX project detectors and software concerning Axions, Dark matter and double beta decay.

The direct detection of dark matter particles requires ultra-low background conditions at energies below a few tens of keV. Radioactive isotopes are produced via cosmogenic activation in detectors and other materials and those isotopes constitute a background source which has to be under control. In particular, tritium is specially relevant due to its decay properties (very low endpoint energy and long half-life) when induced in the detector medium, and because it can be generated in any material as a spallation product. Quantification of cosmogenic production of tritium is not straightforward, neither experimentally nor by calculations. In this work, a method for the calculation of production rates at sea level has been developed and applied to some of the materials typically used as targets in dark matter detectors (germanium, sodium iodide, argon and neon); it is based on a selected description of tritium production cross sections over the entire energy range of cosmic nucleons. Results have been compared to available data in the literature, either based on other calculations or from measurements. The obtained tritium production rates, ranging from a few tens to a few hundreds of nuclei per kg and per day at sea level, point to a significant contribution to the background in dark matter experiments, requiring the application of specific protocols for target material purification, material storing underground and limiting the time the detector is on surface during the building process in order to minimize the exposure to the most dangerous cosmic ray components., Final version as published

Çetin, Serkant Ali (Dogus Author) -- Arık, Metin (Dogus Author) -- Yıldız, Süleyman Cenk (Dogus Author) Although they have not yet been detected, axions and axion-like particles (ALPs) continue to maintain the interest (even increasingly so) of the rare-event searches community as viable candidates for the Dark Matter of the Universe but also as a solution for several other puzzles of astrophysics. Their property of coupling to photons has inspired different experimental methods for their detection, one of which is the helioscope technique. The CERN Axion Solar Telescope (CAST) is the most sensitive helioscope built up to date and has recently published part of the latest data taken with the magnet bores gradually filled with He-3, probing the mass range up to 1.17 eV. The International AXion Observatory (IAXO) is being proposed as a facility where different axion studies can be performed, with the primary goal to study axions coming from the Sun. Designed to maximize sensitivity, it will improve the levels reached by CAST by almost 5 orders of magnitude in signal detection, that is more than one order of magnitude in terms of gay. Here we will summarize the most important aspects of the helioscopes, and focus mainly on IAXO, based on the recent papers [1, 2].

This paper examines the moral reasoning trends of CEOs (chief executive officers) in the automotive industry, gauging their relations to ethical behaviors and scandals as well as analyzing the influence of scandals and other factors on their moral reasoning. For such a purpose, we carried out a moral reasoning categorization for the top 15 automotive companies in vehicle production in 2017 by applying Weber&rsquo, s method to letters written by CEOs for the period 2013&ndash, 2018. A positive global trend was observed, with some CEOs reaching high levels, although the evolution was uneven without clear patterns and, in the light of facts, not sufficient, at least in the short term. We also found evidence linking the moral reasoning stages with the ethical performance of companies and introduced the concept &ldquo, tone &lsquo, into&rsquo, the top&rdquo, reflecting how CEO moral reasoning can be shaped by the company and external factors. This paper stresses the importance of considering the moral tone at the top in relation to company ethical behaviors and the interest of education in business ethics. The outcome is useful for CEOs and other managers seeking to improve corporate social responsibility (CSR) and company ethical performance and to anticipate conflicts as well as to leverage for future research.

Axion helioscopes search for solar axions and axion-like particles via inverse Primakoff conversion in strong laboratory magnets pointed at the Sun. While helioscopes can always measure the axion coupling to photons, the conversion signal is independent of the mass for axions lighter than around 0.02 eV. Masses above this value on the other hand have suppressed signals due to axion-photon oscillations which destroy the coherence of the conversion along the magnet. However, the spectral oscillations present in the axion conversion signal between these two regimes are highly dependent on the axion mass. We show that these oscillations are observable given realistic energy resolutions and can be used to determine the axion mass to within percent level accuracies. Using projections for the upcoming helioscope IAXO, we demonstrate that $>3\sigma$ sensitivity to a non-zero axion mass is possible between $3 \times 10^{-3}$ and $10^{-1}$ eV for both the Primakoff and axion-electron solar fluxes., Comment: 13 pages, 7 figures, matches published version, code available at http://cajohare.github.io/IAXOmass

Çetin, Serkant Ali (Dogus Author) -- Conference full title: 13th International Conference on Topics in Astroparticle and Underground Physics, TAUP 2013; Asilomar Conference Grounds Monterey Peninsula; United States; 8 September 2013 through 13 September 2013. The International Axion Observatory (IAXO) is a proposed 4th-generation axion helioscope with the primary physics research goal to search for solar axions via their Primakoff conversion into photons of 1 - 10 keV energies in a strong magnetic field. IAXO will achieve a sensitivity to the axion-photon coupling gaγ down to a few ×10-12 GeV-1 for a wide range of axion masses up to ∼ 0.25 eV. This is an improvement over the currently best (3rd generation) axion helioscope, the CERN Axion Solar Telescope (CAST), of about 5 orders of magnitude in signal strength, corresponding to a factor ∼ 20 in the axion photon coupling. IAXO's sensitivity relies on the construction of a large superconducting 8-coil toroidal magnet of 20 m length optimized for axion research. Each of the eight 60 cm diameter magnet bores is equipped with x-ray optics focusing the signal photons into ∼ 0.2 cm2 spots that are imaged by very low background x-ray detectors. The magnet will be built into a structure with elevation and azimuth drives that will allow solar tracking for 12 hours each day. This contribution is a summary of our papers [1-3] and we refer to these for further details.

International audience; Searching for the neutrinoless double beta decay (NLDBD) is now regarded as the topmost promising technique to explore the nature of neutrinos after the discovery of neutrino masses in oscillation experiments. PandaX-III (particle and astrophysical xenon experiment III) will search for the NLDBD of$^{136}$Xe at the China Jin Ping Underground Laboratory (CJPL). In the first phase of the experiment, a high pressure gas Time Projection Chamber (TPC) will contain 200 kg, 90%$^{136}$Xe enriched gas operated at 10 bar. Fine pitch micro-pattern gas detector (Microbulk Micromegas) will be used at both ends of the TPC for the charge readout with a cathode in the middle. Charge signals can be used to reconstruct the electron tracks of the NLDBD events and provide good energy and spatial resolution. The detector will be immersed in a large water tank to ensure ~5 m of water shielding in all directions. The second phase, a ton-scale experiment, will consist of five TPCs in the same water tank, with improved energy resolution and better control over backgrounds.

Micromegas detectors, thanks to the good spatial and temporal discrimination capabilities, are good candidates for rare event search experiments. Recent X-ray background levels achieved by these detectors in the CAST experiment have motivated further studies in the nature of the background levels measured. In particular, different shielding configurations have been tested at the Canfranc Underground Laboratory, using a microbulk type detector which was previously running at the CAST experiment. The first results underground show that this technology, which is made of low radiative materials, is able to reach background levels up to $2 \times 10^{-7}$keV$^{-1}$s$^{-1}$cm$^{-2}$ with a proper shielding. Moreover, the experimental background measurements are complemented with Geant4 simulations which allow to understand the origin of the background, and to optimize future shielding set-ups., Comment: Proceedings of the 3rd International conference on Directional Detection of Dark Matter (CYGNUS 2011), Aussois, France, 8-10 June 2011

Yıldız, Süleyman Cenk (Dogus Author) Micromegas detectors have been taking data in the CAST experiment since 2002, occupying one opening (out of the two looking for sunrise axions) of the magnet and showing good performance and stability. Currently, three of the four X-ray detectors used in the experiment are micromegas. The new detectors are of the Microbulk technology, which have attracted a lot of attention because of the advantages they present, among them the low-material construction, high radiopurity and good energy resolution. Here, their performance during the last year will be commented. In particular, the low background levels reached in some detectors have triggered a set of studies in order to understand the effect.

The measurement of the direction of WIMP-induced nuclear recoils is a compelling but technologically challenging strategy to provide an unambiguous signature of the detection of Galactic dark matter. Most directional detectors aim to reconstruct the dark-matter-induced nuclear recoil tracks, either in gas or solid targets. The main challenge with directional detection is the need for high spatial resolution over large volumes, which puts strong requirements on the readout technologies. In this paper we review the various detector readout technologies used by directional detectors. In particular, we summarize the challenges, advantages and drawbacks of each approach, and discuss future prospects for these technologies., Comment: 58 pages, 26 figures, accepted by Physics Reports

A low background Micromegas detector has been operating on the Cern Axion Solar Telescope (CAST) experiment at CERN for the search of solar axions during the first phase of the experiment. The detector operated efficiently and achieved a very low level of background rejection ( 5 × 10 - 5 counts keV - 1 cm - 2 s - 1 ) thanks to its good spatial and energy resolution as well as the low radioactivity materials used in the construction of the detector. For the second phase of the experiment, the detector is being upgraded by adding a shielding and including focusing optics. These improvements should allow for a background rejection better than two orders of magnitude. The preliminary results of the first tests in the laboratory and in the PANTER X-ray test facility will be shown.

The search for the neutrinoless double beta decay (0$\nu\beta\beta$) is one of the most important quests nowadays in neutrino physics. Among the different techniques used, high pressure xenon (HPXe) gas time projection chambers (TPC) stand out because they allow to image the topology of the 0$\nu\beta\beta$ event (one straggling track ending in two blobs), and use it to discriminate signal from background events. Recent results with microbulk Micromegas in Xe + trimethylamine (TMA) mixtures show high promise in terms of gain, stability of operation, and energy resolution at high pressures (up to 10 bar). The addition of TMA at levels of ~1\% reduces electron diffusion in up to a factor of 10 with respect pure Xe, improving the quality of the topological pattern, and therefore the discrimination capability. Moreover microbulk Micromegas have very low levels of intrinsic radioactivity. All these results show that a Micromegas-read High Pressure Xenon TPC (HPXe-TPC) can be a competitive technique in the search for 0$\nu\beta\beta$. The recently proposed PandaX-III experiment, based on these results, aims at building a large TPC of 200 kg of enriched Xe, to be located at Jinping Underground laboratory in China. In this talk the main features of the experiment will be presented, with an emphasis on the design and tests of the microbulk readout, as well as the status of the project and first results of the prototyping phase., Comment: Proceedings of the MPGD 2015 conference. Trieste

The CERN Axion Solar Telescope (CAST) searches for a -> gamma conversion in the 9 T magnetic field of a refurbished LHC test magnet that can be directed toward the Sun. Two parallel magnet bores can be filled with helium of adjustable pressure to match the x-ray refractive mass m(gamma) to the axion search mass m(a). After the vacuum phase (2003-2004), which is optimal for m(a) less than or similar to 0.02 eV, we used He-4 in 2005-2007 to cover the mass range of 0.02-0.39 eV and He-3 in 2009-2011 to scan from 0.39 to 1.17 eV. After improving the detectors and shielding, we returned to He-4 in 2012 to investigate a narrow m(a) range around 0.2 eV ("candidate setting" of our earlier search) and 0.39-0.42 eV, the upper axion mass range reachable with He-4, to "cross the axion line" for the KSVZ model. We have improved the limit on the axion-photon coupling to g(a gamma) < 1.47 x 10(-10) GeV-1 (95% C.L.), depending on the pressure settings. Since 2013, we have returned to the vacuum and aim for a significant increase in sensitivity.

Axion helioscopes search for solar axions by their conversion in x-rays in the presence of high magnetic fields. The use of low background x-ray detectors is an essential component contributing to the sensitivity of these searches. In this work, we review the recent advances on Micromegas detectors used in the CERN Axion Solar Telescope (CAST) and proposed for the future International Axion Observatory (IAXO). The actual setup in CAST has achieved background levels below 10$^{-6}$ keV$^{-1}$ cm$^{-2}$ s$^{-1}$, a factor 100 lower than the first generation of Micromegas detectors. This reduction is based on active and passive shielding techniques, the selection of radiopure materials, offline discrimination techniques and the high granularity of the readout. We describe in detail the background model of the detector, based on its operation at CAST site and at the Canfranc Underground Laboratory (LSC), as well as on Geant4 simulations. The best levels currently achieved at LSC are low than 10$^{-7}$ keV$^{-1}$ cm$^{-2}$ s$^{-1}$ and show good prospects for the application of this technology in IAXO. Finally, we present some ideas and results for reducing the energy threshold of these detectors below 1 keV, using high-transparent windows, autotrigger electronics and studying the cluster shape at different energies. As a high flux of axion-like-particles is expected in this energy range, a sub-keV threshold detector could enlarge the physics case of axion helioscopes., Comment: Proceedings of 3rd International Conference on Technology and Instrumentation in Particle Physics (TIPP 2014)