Search

The first stage of LHAASO-KM2A has been completed in Sichuan, China. KM2A is composed of electromagnetic particle detectors (ED) and muon detectors (MD), focusing on gamma ray astronomy above 30 TeV and cosmic ray physics in the “knee” region. The ED array in the first stage is installed into two clusters and the distance between the two clusters is around 230 meters. The MDs are distributed in one of the clusters. Each MD is covered with soil of 2.5 meters thick. We analyzed the lateral distribution of muons which are 140-300 meters away from Shower axis, and the primary cosmic ray energy is about 100TeV.

The Tibet air shower (AS) array and underground water-Cherenkov-type muon detector (MD) array have been successfully operated since 2014, at an altitude of 4,300 m in Tibet, China. we observed 24 gamma-ray events with energy greater than 100 TeV against 5.5 background events, which corresponds to 5.6$\sigma$ statistical significance (Amenomori et al. 2019). The highest energy of the detected gamma rays is estimated to be 450 TeV. This is the first detection of gamma rays beyond 100 TeV from an astrophysical source, and a pioneering work opening a new higher energy window in the astronomy and astrophysics.

We present the results of a search for pulsed gamma-ray emission in the 100 TeV region from several pulsars using data taken with the Tibet air shower (AS) array and a water Cherenkov type muon detector (MD) array. The Tibet AS$¥gamma$ experiment has improved significantly gamma-ray sensitivity by the constructed MD array since 2014. Based on the observational data with the AS + MD array, we will report data on several famous pulsars in the northern hemisphere in this presentation.

Aiming at observing cosmic gamma rays in the energy region beyond several tens of TeV, a water-Cherenkov-type muon detector (MD) array was built under the Tibet air shower (AS) array. The Tibet AS+MD array, which possess high sensitivity to gamma rays beyond 10 TeV, has been operated since 2014. We performed analysis of gamma rays from the Geminga PWN using data collected by the Tibet AS+MD array. We report on the gamma-ray energy spectrum beyond 10 TeV and the morphology of >10 TeV gamma rays.

The CMS experiment uses a sophisticated two-level triggering system composed of hardwarebased Level-1 Trigger, and a software-based High Level Trigger to select 1 kHz of events out of 40 MHz for later analysis. A new Level-1 trigger architecture improves the data taking performance at high luminosity experienced during Run II. The upgraded muon trigger increases the redundancy of the three muon detectors - Cathode Strip Chambers (CSC), Drift Tubes (DT), and Resistive Plate Chambers (RPC) - by combining information in the muon track finders with new track reconstruction, which yields a better efficiency and lower rates. The upgraded muon trigger system and the algorithms designed to select events for both precision measurements and new physics searches are described. The performance of the upgraded muon trigger system is demonstrated using proton-proton collision data collected in Run II.

The $$\gamma $$ -ray astronomy at 100 TeV is important to unravel the puzzles related to the origin and acceleration of the Galactic cosmic rays up to PeV energy. The YangBaJing Hybrid Array (YBJ-HA), about 2% the scale of LHAASO-KM2A, is such a kind of detection instrument capable of detecting 100 TeV $$\gamma $$ -rays. And the muon detection efficiency stability of the MD array in YBJ-HA is crucial for high quality $$\gamma $$ -ray observation. To measure and monitor the muon detection efficiency, we develop a method in this work. We develop a muon bundle method to measure and monitor the efficiency of each muon detector. In this method, muon detection efficiency of the target MD unit is calculated based on the surrounding MD units and the MC simulation. The average actual muon detection efficiency of the 16 MD units is up to 83.4% during 4 years’ observation. The muon detection efficiency of each MD unit is found to be stable during 4 years’ operation. In the future, a similar method may be applicable to the muon detection efficiency study for LHAASO.

With its ∼ 1650 m 2 of MWPCs, the muon detector of LHCb is one of the largest instrument of this kind worldwide, and one of the most irradiated. Currently we run at the relatively low instantaneous luminosity of 4 ⋅ 1 0 32 c m − 2 s − 1 , nevertheless the most irradiated MWPCs already integrated ∼ 0.7 C/cm of accumulated charge per wire. The statistics of gas gaps affected by high voltage trips in the proportional chambers is presented for the whole period of operation. Most of the problematic chambers were successfully recovered in situ during data taking, under the nominal LHC beam conditions, by means of a long-term HV training (with the working gas mixture). The appearing of self-sustained currents in one of the MWPC gaps and the effectiveness of the recovery procedures put in place, indicate that the large majority of the trips are due to Malter effect. The method has proven to be very effective, allowing to keep the muon detector efficiency very close 100%, as it was initially designed. In parallel, a test has been performed of a systematic addition of a small amount of oxygen to the nominal gas mixture: results of this test will be discussed.

The CMS Muon System has been operated successfully during the two LHC runs allowing to collect a very high fraction of data with a quality that fulfils the requirements to be used for physics analysis. Nevertheless, the workflows used nowadays to operate and monitor the detector are rather expensive in terms of human resources. Focus is therefore being put on improving such workflows, both by applying automated statistical tests and exploiting modern machine learning algorithms, in view of the future LHC runs. The ecosystem of tools presently in use will be presented, together with the state of the art of the developments toward more automatized monitoring and the roadmap for the future.

Images of the CMS Muon area during 2019 Open Days at CERN

A full-size prototype of a Micromegas precision tracking chamber for the upgrade of the ATLAS detector at the LHC Collider has been built between October 2015 and April 2016. This paper describes in detail the procedures used in constructing the single modules of the chamber in various INFN laboratories and the final assembly at the Laboratori Nazionali di Frascati (LNF). Results of the chamber exposure to the CERN SPS/H8 beam line in June 2016 are also presented. The performances achieved in the construction and the results of the test beam are compared with the requirements, which are imposed by the severe environment during the data-taking of the LHC foreseen for the next years., Contact editors: G. Mancini, A. Kourkoumeli-Charalampidi

Pictures from CMS Cathode Strip Chambers installation on Thursday 25th July 2019

Pictures of the 2 first GEMs superchamber transportation and lowering from Prévessin GEM Lab to CMS P5 Cessy on Wednesday 24th July 2019

The Pierre Auger Observatory has been very successful in determining many aspects of the highest-energy cosmic rays including, among others, the flux suppression at energies above 4 × 1019 eV, stringent upper limits on photon and neutrino fluxes at ultra-high energies and an unexpected evolution of the mass composition with energy. We expect an extension of the frontiers of our knowledge on these aspects from a major upgrade of the Observatory. The upgrade, known as AugerPrime, will include an addition of a 4 m2 Surface Scintillator Detector atop each water-Cherenkov station of the Surface array. The new detectors will provide us with an unprecedented opportunity to perform a complementary measurement of the shower particles and thus determine the primary mass composition with good accuracy on an event-by-event basis. AugerPrime will also include an upgrade of electronics, installation of the AMIGA Underground Muon Detector and a change of observation mode of the Fluorescence Detector, which will increase its current duty cycle by about 50%. Current status of the upgrade with the main focus on the Surface Scintillator Detectors will be presented, following a brief description of the physics motivation for the upgrade.

Pictures of the first GEM superchamber installations into CMS detector on Thursday 25 July 2019

The Carpet air shower array of the Baksan Neutrino Observatory is in operation for a long time, and it was modernized more than once. A short review of important results obtained with this array is given, as well as future prospects, since at the moment the new project called Carpet-3 is in progress, using the old array as its basis. The purpose of the new project is to substantially increase the muon detector area (quite soon up to 400 m2 and later up to 600 m2). This improvement will allow one to reach a very good sensitivity to diffuse cosmic photons by selecting muon-poor showers. The energy range where the new experiment will be competitive with other experiments of gamma-ray astronomy is near and below 100 TeV.

It is well known that the cosmic ray intensity observed at the Earth's surface presents an 11 and 22-yr variations associated with the solar activity cycle. However, the observation and analysis of this modulation through ground muon detectors datahave been difficult due to the temperature effect. Furthermore, instrumental changes or temporary problems may difficult the analysis of these variations. In this work, we analyze the cosmic ray intensity observed since October 1970 until December 2012 by the Nagoya muon detector. We show the results obtained after analyzing all discontinuities and gaps present in this data and removing changes not related to natural phenomena. We also show the results found using the mass weighted method for eliminate the influence of atmospheric temperature changes on muon intensity observed at ground. As a preliminary result of our analyses, we show the solar cycle modulation in the muon intensity observed for more than 40 years.

Die ultra hochenergetische kosmisch Strahlung besteht aus Teilchen, die mit Energien von über $10^{18}$ eV auf die Erde gelangen. Wenn diese auf Atomkerne in der Erdatmosphäre treffen, entstehen Sekundärteilchen. Diese propagieren als ausgedehnte Luftschauer bis zum Boden hin. Zu diesen extrem energiereichen kosmischen Strahlen gibt es noch eine Reihe von offenen Fragen: Was sind deren Quellen? Was sind die Beschleunigungsmechanismen, die ihnen den Ursprung geben, sowie ihre Zusammensetzung (der Anteil von Protonen und verschiedenen Kerntypen)? Welche Mechanismen sorgen für die Unterdrückung bei sehr hohen Energien. Um diese Fragen zu l”osen, werden am Pierre Auger Observatorium kosmische Strahlen mit den höchsten Energien untersucht. Dafür wird eine Hybriddetektionstechnik verwendet, die darauf abzielt, sowohl die Teilchenstatistik zu verbessern als auch systematische Unsicherheiten zu minimieren. Derzeit werden die Messkapzit”aten vom Pierre Auger Observatorium, im Rahmen des AugerPrime Upgrades, verbessert. Dafür werden neue Detektoren wie Radioantennen, Oberflächen-Szintillatordetektoren und Untergrund-Szintillatordetektoren eingesetzt. Das "Auger Muon and Infill for the Ground Array'' (AMIGA) zielt darauf ab, sowohl die Nachweisgrenze des Pierre Auger Observatoriums auf Energien von $\sim$ $10^{16.5}$ eV zu senken als auch den Myongehalt von ausgedehnten Luftschauern direkt zu messen. AMIGA besteht aus einer Reihe von gekoppelten Wasser-Cherenkov- und vergrabenen Szintillatordetektoren, die in zwei überlappenden Dreiecksgittern im Abstand von 433 m und 750 m eingesetzt werden. Jeder Untergrunddetektor hat eine Gesamtfläche von 30 $\mathrm{m}^2$ und ist 2,3 m unter der Erdoberfl”ache vergraben, um es vor der elektromagnetischen Komponenten der Schauer zu schützen. Die Szintillationsebene ist in Kunststoff-Szintillatorstreifen mit eingebetteten optischen Wellenlängenschieberfasern segmentiert, die mit einer Reihe von Silizium-Photomultiplier (SiPMs) gekoppelt sind. In dieser Arbeit stellen wir mehrere Studien über den AMIGA Untergrund-Myonendetektor (UMD) vor, der zwei Betriebsarten hat: den Zähler, der entwickelt wurde, um Myonen direkt zu messen, wenn sie auf den Detektor treffen, und optimiertist, um niedrige Myondichten zu messen, und den Integrator, der es ermöglicht, den Myongehalt von ausgedehnten Luftschauern zu schätzen, indem es die Gesamtladung durch die eines durchschnittlichen Myons teilt. Zunächst beschreiben wir die aktuelle Kalibrierung für die SiPMs und wie der Arbeitspunkt des Zählermodus eingestellt wird. Unter Verwendung von Labordaten und Messungen des Observatoriums haben wir Studien durchgeführt, um die Stabilität der SiPM-Verstärkung bei Temperaturschwankungen zu bestätigen. Wir haben deren Rauschquellen gründlich charakterisiert. Dazu haben wir auch eine Myon-Zählstrategie vorgeschlagen, die das SiPM-Rauschen minimiert, ohne signifikant an Myonsignalen zu verlieren. Wir haben auch Daten aus dem Labor und dem Observatorium verwendet, um die Hauptmerkmale des Integrator-Modus zu extrahieren und ein Unsicherheitsmodell für die Signalladung zu erhalten. Zudem haben wir zwei mögliche Kalibrierungsverfahren für diesen Modus vorgestellt: das erste basiert auf Luftschauerereignissen, die offline durchgeführt werden können, und das zweite auf Hintergrunddaten, die online durchgeführt werden können. Außerdem wurden als Teil dieser Arbeit die AMIGA UMD-Simulationen entwickelt und in die Auger Datenanalyse- und Simulationssoftware ( Offline) implementiert. Der Code wurde mit Labordaten entwickelt und mit identischen Komponenten, wie die im UMD-Enddesign gemessen wurden, validiert. Sowohl analoge SiPM-Impulse als auch digitale Spuren nach der Frontend-Platine wurden erfasst und mit Simulationsergebnissen verglichen; erstere mit spezifischer Elektronik und letztere mit den gleichen elektronischen Bausätzen, die in der UMD-Produktion verwendet werden. Die Hauptmerkmale der Zähler- und Integratorkanäle sind relevant f”ur die Detektorleistung und werden hier diskutiert. Deren Unterschiede und Übereinstimmungen zwischen Simulations- und Labordaten werden dargestellt. Schließlich haben wir die neulich implementierten SiPM-Simulationen im Offline-Framework verwendet, um die Quellen systematischer Fehler des Zähler-Modus zu untersuchen und Korrekturen vorzuschlagen, die etwaige Rekonstruktionsverzerrungen beseitigen. Wir haben die Simulationen auch verwendet, um die Kalibrierung des Integratormodus zu testen und die Auflösungen beider Modii zu vergleichen. Wir haben diese Ergebnisse verwendet, um die Empfindlichkeit der UMD gegenüber der kosmischen Strahlungsprimärmasse zu untersuchen. Im Rahmen dieser Dissertation wurden mehrere Beiträge zum AugerPrime Upgrade erarbeitet. Unter anderem wurden: (i) Studien zur Bestätigung der Stabilität von SiPMs, (ii) die Prüfung und Abstimmung des SiPM-Kalibrierverfahrens und die Überprüfung seiner Robustheit, (iii) die Charakterisierung von UMD-Signalen und Rauschquellen, (iv) die Bestimmung der Effizienz und Dämpfung von Szintillatorstreifen mit eingebetteter Glasfaser (v) die Erreichung einer Zählstrategie zur Schätzung der Anzahl der Myonen in Luftschauern mit dem Counter-Modus, (vi) die Kalibrierung des Integratormodus unter Verwendung von Online- und Offline-Daten, (vii) das Design, die Entwicklung, die Implementierung und das Testen von SiPM- und elektronischen Simulationen, (viii) das Design, die Entwicklung, die Implementierung und das Testen der UMD-Ereignisvisualisierung in einer grafischen Benutzeroberfläche, (ix) Analysen über die Auswirkungen des Bodens bei der UMD-Rekonstruktion, (x) das Erreichen einer Rekonstruktionsverzerrungskorrektur für den Counter-Modus mit SiPMs, (xi) Analysen zur Verbesserung der UMD-Fähigkeiten zur Durchführung von Studien über die Zusammensetzung der kosmischen Strahlung, durchgeführt. Die in dieser Arbeit beschriebenen Werkzeuge und Methoden sind von größter Bedeutung für zukünftige Analysen mit dem unterirdischen AugerPrime Myonendetektor.

Triple-GEM detector technology was recently selected by CMS for a part of the upgrade of its forward muon detector system as GEM detectors provide a stable operation in the high radiation environment expected during the future High-Luminosity phase of the Large Hadron Collider (HL-LHC). In a first step, GEM chambers (detectors) will be installed in the innermost muon endcap station in the $1.6, Comment: 23 pages, 24 figures

In this work, we predict the line shape of potential fully-heavy structures existed in the invariant mass spectrum of J / ψ ψ ( 3686 ) , J / ψ ψ ( 3770 ) , ψ ( 3686 ) ψ ( 3686 ) , and J / ψ ϒ ( 1 S ) at high energy proton-proton collisions based on a dynamical rescattering picture, whose verification in experiments should be helpful to further clarify the dominant role in producing fully-charm structure X ( 6900 ) recently observed by LHCb. The above final states of vector heavy quarkonia can be experimentally reconstructed more effectively by a μ + μ − pair in the muon detector compared with Q Q ¯ meson with other quantum numbers. Furthermore, the corresponding peak mass positions of each of predicted fully-heavy structures are also given. Our theoretical studies here could provide some valuable information for the future measurement proposals of LHCb and CMS, especially based on the accumulated data after completing Run III of LHC in the near future.

Muon detectors and neutron monitors were recently installed at Syowa Station, in the Antarctic, to observe different types of secondary particles resulting from cosmic ray interactions simultaneously from the same location. Continuing observations will give new insight into the response of muon detectors to atmospheric and geomagnetic effects. Operation began in February, 2018 and the system has been stable with a duty-cycle exceeding 94%. Muon data shows a clear seasonal variation, which is expected from the atmospheric temperature effect. We verified successful operation by showing that the muon and neutron data are consistent with those from other locations by comparing intensity variations during a space weather event. We have established a web page to make real time data available with interactive graphics (http://polaris.nipr.ac.jp/~cosmicrays/)., Accepted for publication in the Journal of Space Weather and Space Climate

We performed three-dimensional density modeling of Showa-Shinzan lava dome, Usu, Japan, by joint inversion of the gravity anomaly and recently obtained muon radiography data. Our multilayer emulsion muon detector significantly reduces the background noise in our measurements of the muon flux through the dome. The high-quality muon data enables us to more accurately reconstruct the density structure of the lava dome compared with our own previous work. We find that the lava dome consists of a cylindrical column of massive lava with a diameter of 300 m, and that there is no evidence of magma intrusion in the shallow part of the plateau, located east of the dome.

Quarkonium measurements in heavy-ion collisions play an essential role in understanding the hot, dense medium created in such collisions. As a reference, their production mechanism in p + p collisions needs to be thoroughly understood. In this paper, we report the measurement of inclusive cross section of J / ψ with transverse momentum (pT) above 4 GeV/c at mid-rapidity in p + p collisions at s = 500 GeV by the STAR experiment. The ratio of the yield of ψ ( 2 S ) to J / ψ integrated over 4 p T 12 GeV / c is also presented. Furthermore, the J / ψ yields are studied in different event multiplicity bins in different J / ψ pT regions, where the low pT measurement is enabled by the newly installed Muon Telescope Detector. A strong increase of the relative J / ψ yield with the event multiplicity is observed for all pT with significant pT dependence.

The 1-GeV muon–hadron detector of the Carpet-2 multipurpose shower array at the Baksan Neutrino Observatory, Institute for Nuclear Research, Russian Academy of Sciences (INR, Moscow, Russia) is able to record simultaneously muons and hadrons. The procedure developed for this device makes it possible to separate the muon and hadron components to a high degree of precision. The spatial and energy features of the muon and hadron extensive-air-shower components are presented. Experimental data from the Carpet-2 array are contrasted against data from the EAS-TOP and KASCADE arrays and against the results of the calculations based on the CORSIKA (GHEISHA + QGSJET01) code package and performed for primary protons and iron nuclei.

The CMS muon system has played a key role for many physics results obtained from the LHC Run 1 data. The LHC will increase the beam energy as well as progressively increase the peak instantaneous luminosity in Run 2 and in the following years. Significant consolidation and upgrade activities are ongoing, in order to improve the CMS muon detectors and trigger performance and robustness. With LHC and then HL-LHC running beyond 2030, the large accumulated radiation dose, the high pileup environment, and the ageing of several detector and electronics components become challenges that can only be met with further development and upgrade work. We will introduce the CMS muon system and present the consolidation work in preparation for LHC Run 2. We will then describe the main constraints and the solutions proposed for the upgrade of the muon detector system towards HL-LHC.

Remote detection of radioactive materials is extremely challenging, yet it is important to realize the technique for safe usage of radioactive materials. Gamma rays are the most far distant penetrating photons that are involved with the radiation decay process. Herein, we overview the gamma-ray detection techniques that are material-based and vacuum tube-based. A muon detector is also reviewed as a radioactive material imager. We overview versatile detectors that are currently being widely used and new concepts that may pave the way for promising remote detectability up to several kilometers.

The Large High Altitude Air Shower Observatory (LHAASO) is a hybrid detector array, which will be capable of surveying the north VHE gamma-ray sky from 100 GeV to 1 PeV. The muon detector is a kind of water Cherenkov detector; thus, its optical properties are crucial for construction and understanding of the detector. We designed a series of methods to measure the optical parameters of water and inner layer, and the results from different methods are consistent with each other, which proves the reliability of the measurement results and provides an improved understanding of the detector.

Los rayos cósmicos (E > 1014 eV) son conocidos desde hace más de 70 años y, sin embargo, su origen sigue siendo un misterio. Del mismo modo, la posibilidad de una componente fotónica de muy alta energía en el flujo de radiación cósmica es uno de los problemas abiertos en la Física de Astropartículas. La búsqueda de fotones de alta energía complementa las mediciones de los rayos cósmicos y neutrinos hacia una comprensión multi-canal de los fenómenos astrofísicos más energéticos. En particular, el descubrimiento de fotones con energías entre 1016.5 eV y 1018 eV en el flujo de los rayos cósmicos podría ser de particular interés no sólo para el campo de la Física de Astroparticulas, sino también para la Astrofísica y la Física fundamental, ya que son rastreadores de los procesos de mayor energía en el Universo. En la búsqueda de fotones de ultra-alta energía, es crucial definir parámetros sensibles a la composición capaces de rechazar adecuadamente el fondo hadrónico de los rayos cósmicos. El contenido muónico de las lluvias atmosféricas extensas producidas por los rayos cósmicos primarios al entrar en la atmósfera es uno de los aspectos más prometedores que podría conducir a la mejor discriminación posible entre los fotones y los rayos cósmicos hadrónicos. El detector de muones subterráneo AMIGA, como parte de la próxima mejora AugerPrime del Observatorio Pierre Auger, ofrece una oportunidad única y directa para medir muones de alta energía de lluvias atmosféricas extensas, y así, aumentar la sensibilidad del Observatorio a una señal fotónica primaria. La Colaboración Pierre Auger ha propuesto varios parámetros para estudiar una posible componente fotónica de ultra-alta energía en el flujo hadrónico de rayos cósmicos. Sin embargo, su no-observación resultó en límites superiores para energías por encima de 1018 eV. Por otra parte, la ventana energética entre 1016.5 eV y 1018 eV sólo ha sido explorada por los experimentos de KASCADE-Grande y EAS-MSU, que imponen límites superiores al flujo fotónico. Actualmente, este dominio energético no es explorado por el Observatorio Pierre Auger. El objetivo principal de esta tesis es la extensión de la búsqueda de fotones de ultra alta energía hasta ∼ 1016.5 eV. Los estrictos límites superiores teóricos y experimentales al flujo fotónico en estas energías hacen que la búsqueda de una débil señal fotónica en el vasto fondo de los rayos cósmicos hadrónicos sea una tarea desafiante. Por lo tanto, los parámetros sensibles a la señal predominantemente electromagnética de los fotones primarios son de suma importancia. En este marco, definimos y describimos dos nuevos observables sensibles a la composición diseñados para la discriminación fotón/hadrón con el fin de detectar fotones primarios a energías del orden de 1016 eV o mejorar los límites superiores establecidos por experimentos anteriores. El observable Mb combina las densidades de muón medidas por las estaciones de muón subterráneas AMIGA y su distancia al eje de la lluvia, de manera similar al conocido parámetro Sb utilizado anteriormente en las búsquedas fotónicas por la Colaboración Pierre Auger. Por otra parte, el observable Q explota la diferencia en la pendiente de la distribución lateral de partículas entre las lluvias iniciadas por fotones y hadrones. En este último caso, se espera que las lluvias se desarrollen a mayores alturas en la atmósfera y lleguen al suelo con una distribución más plana de partículas. En este trabajo, afinamos ambos observables para ser aplicados en el detector de superficie y detector de muones del Observatorio Auger para energías por encima de Erec = 1016.4 eV y θ < 45°. Un método multiparamétrico, bautizado Mb + Q, es extensamente estudiado y su ejecución se aborda bajo numerosas condiciones. Se demuestra que el rechazo de fondo y la eficiencia de la señal para el método compuesto son adecuados para imponer los mejores límites superiores de todos los experimentos de rayos cósmicos con tan sólo unos pocos años de datos, y en particular mejorarlos por un orden de magnitud al final actualmente planificado de operación de Auger el 31 de diciembre 2025. Considerando la alta exposición del experimento Auger en dirección al centro galáctico, el método descrito en esta tesis representa una herramienta valiosa con un potencial de descubrimiento sin precedentes en la detección de una señal fotónica minúscula en el flujo de rayos cósmicos. Aunque en esta investigación se presenta una estimación ciega de la sensibilidad a un flujo fotónico, está previsto que la aplicación a los datos se lleve a cabo en un futuro próximo para una publicación oficial de la Colaboración Pierre Auger. Cosmic rays (E > 1014 eV) have been known for more than 70 years, and yet their origin remains elusive. Similarly, the possibility of a very-high energy photon component of the cosmic radiation is one of the open problems in Astroparticle Physics. The search for high energy photons complements measurements of cosmic rays and neutrinos towards a multi-messenger understanding of the most energetic astrophysical phenomena. In particular, the discovery of photons with energies between 1016.5 eV and 1018 eV in the cosmic rays flux could be of particular interest not only for the field of Astroparticle Physics, but also for Astrophysics and fundamental Physics, since they are tracers of the highest-energy processes in the Universe. In the search for ultra-high energy photons, it is crucial to define composition-sensitive parameters capable of adequately rejecting the hadronic cosmic-ray background. The muon content of the extensive air showers produced by primary cosmic rays as they enter the atmosphere is one of the most promising aspects that could lead to the best possible discrimination between photons and hadronic cosmic rays. The AMIGA underground muon detector, as a part of the upcoming AugerPrime upgrade for the Pierre Auger Observatory, offers a unique and straight-forward opportunity to directly measure high-energy muons of extensive air showers, and thus, enhance the sensibility of the Observatory to a primary photon signal. The Pierre Auger Collaboration has proposed several parameters in order to study a possible ultra-high energy photon component in the hadronic cosmic-ray flux. However, the nonobservation of photon candidates resulted in upper limits for energies above 1018 eV. On the other hand, the energy window between 1016.5 eV and 1018 eV has only been explored by the KASCADEGrande and the EAS-MSU experiments which impose upper limits to the photon flux. Currently, this energy domain is not explored by the Pierre Auger Observatory. The main objective of this thesis is the extension of the ultra-high energy photon search down to ∼ 1016.5 eV. The stringent theoretical and experimental upper limits to the photon flux at these energies make the search of a weak photon signal in the vast hadronic cosmic-ray background a challenging task. Therefore, parameters sensitive to the predominantly electromagnetic signal from photon primaries are of paramount importance. In this framework, we define and describe two new composition-sensitive observables designed for the photon/hadron discrimination quest in order to either detect photon primaries in the 1016 eV energy domain or improve the upper limits established by previous experiments. The observable Mb combines the muon densities measured by the AMIGA underground muon stations and their distance to the shower axis, similarly to the well-known Sb parameter used previously in photon searches by the Pierre Auger Collaboration. On the other hand, the observable Q exploits the difference in the slope of the lateral distribution of particles between photon- and hadron-initiated showers. In the latter case, the showers are expected to develop higher in the atmosphere and thus they arrive to the ground with a flatter distribution of particles. In this work, we tune both observables to be applied in the surface and muon detector of the Auger Observatory for energies above Erec = 1016.4 eV and θ < 45°. A multiparametric method, baptized Mb+Q, is extensively studied and its performance is addressed under numerous conditions. The background rejection and the signal efficiency for the compound method is proved to be suitable to impose the best upper limits of all the cosmic-ray experiments with only a few years of data, and particularly improve them by one order of magnitude by the end of Auger planned operation at December 31st 2025. Considering the high exposure of the Auger experiment in the direction of the Galactic center, the method described in this thesis represents a valuable tool with an unprecedented discovery potential in the detection of a minuscule photon signal in the cosmic-ray flux. Although a blind estimation of the sensitivity to a photon flux is presented in this research, the application to data is foreseen to be carried out in the near future for a dedicated full-author list paper of the Pierre Auger Collaboration Kosmische Strahlung (E > 1014 eV) ist seit mehr als 70 Jahren bekannt, jedoch bleiben ihren Ursprung unerklärt. Ebenso ist das Vorhandensein einer hochenergetischen Photonenkomponente der kosmischen Strahlung weiterhin eine offene Frage der Astroteilchenphysik. Die Ergänzung von Messungen kosmischer Strahlung und Neutrinos durch hochenergetische Photonen verfeinert unsere Multi-Messenger-Suche von energetischsten astrophysikalischen Phänomenen. Insbesondere die Entdeckung von Photonen mit Energien zwischen 1016.5 eV und 1018 eV im Fluss der kosmischen Strahlung könnte nicht nur für die Astroteilchenphysik relevant sein, sondern auch für die Astrophysik und die Grundlagenphysik, da sie Indikatoren der energiereichsten Prozesse im Universum sind. Bei der Suche nach ultrahochenergetischen Photonen ist es entscheidend, kompositionssensitive Parameter zu definieren, die in der Lage sind, den Untergrund der hadronischen kosmischen Strahlung adäquat zu eliminieren. Der Myonengehalt der Sekundarteilchen ausgedehnter Luftschauer gehört zu den vielversprechendsten Aspekten bei der Unterscheidung zwischen Photonen und hadronischer kosmische Strahlung. AMIGA, ein sich in 2.5 m Bodentiefe befindlicher Myondetektor, ist Teil des AugerPrime-Upgrades für das Pierre-Auger-Observatorium. Es bietet eine einzigartige Lösung, wobei hochenergetische Myonen von ausgedehnten Luftschauern direkt gemessen werden. Damit wird die Sensivilität des Observatoriums zum Nachweis von Photonen als Primärteilchen drastisch verbessert. Es gab bereits mehrere Ansätze der Pierre-Auger-Kollaboration, um eine mögliche ultrahochenergetische Photonenkomponente in der kosmischen Strahlung zu untersuchen. Die Nichtbeobachtung von Photonenkandidaten führte jedoch zu Obergrenzen für Energien über 1018 eV. Andererseits wurde das Energiefenster zwischen 1016.5 eV und 1018 eV nur von der KASCADEGrande und den EAS-MSU-Experimenten untersucht, strikte Obergrenzen des Photonenflusses bestimmten. Derzeit wird dieser Energiebereich im Rahmen des Pierre-Auger-Observatoriums nicht erforscht. Das Hauptziel dieser Arbeit ist die Erweiterung der ultrahochenergetischen Photonensuche bis zu Energien von ∼ 1016.5 eV. Die strengen theoretischen und experimentellen Obergrenzen des Photonenflusses bei diesen Energien macht die Suche nach einem schwachen Photonensignal bei hohem hadronischen Strahlungsuntergrund zu einer herausfordernden Aufgabe. Daher sind Parameter, die auf das überwiegend elektromagnetische Signal empfindlich sind, wie im Falle von Photonen, von äußerster Wichtigkeit. In diesem Rahmen werden zwei neue photonsensitive Parameter definiert und beschrieben, die für die Suche nach der Photonen-/HadronenDiskriminierung entwickelt wurden, um entweder Photonen im Energiebereich 1016 eV zu detektieren oder die Obergrenzen zu verbessern, die durch bisherige Experimente ermittelt wurden. So wie mit dem Sb Parameter, welcher zuvor bei der Photonensuche der Pierre-Auger-Kollaboration verwendet wurde, wird bei Mb die Myondichte der AMIGA-Stationen und deren Abstand zur Schauerachse kombiniert. Die Observable Q nutzt den Unterschied in der Steilheit der lateralen Verteilung der Teilchen zwischen photon- und hadroninduzierten Luftschauern. Im letzteren Fall wird erwartet, dass sich die Luftschauer in der Atmosphäre höher entwickeln und deshalb mit einer flacheren Teilchenverteilung auf den Boden gelangen. In dieser Arbeit werden die Observablen der Oberflächen- und AMIGA-Detektoren so optimiert, dass sie im Energiebereich über Erec = 1016.4 eV und θ < 45° verwendet werden können. Eine multiparametrische Methode, Mb + Q genannt, wird ausführlich untersucht und ihre Leistungfähigkeit wird unter zahlreichen Bedingungen untersucht. Die Untergrundunterdrückung und der Photonnachweis für das multivariate Verfahren sind geeignet zur Bestimmung der striktesten Obergrenzen aller Experimente in diesem Energiebereich innerhalb nur weniger Jahre Messzeit. Bis zum Ende der geplannt Laufzeit des Observatoriums wird eine um eine Größenornung verbesserte Obergrenze erwartet. In Anbetracht der hohen Exposition des AugerExperiments in Richtung des galaktischen Zentrums, stellt die in dieser Arbeit beschriebene Methode ein wertvolles Werkzeug dar eine winziges Photonensignal im galaktischen Strahlungsfluss zu finden. Obwohl im wesentlichen nur eine Blindstudie zur Empfindlichkeit eines Photonenflusses in dieser Studie vorgestellt wird, ist die Anwendung auf Daten in naher Zukunft im Rahmen einer Auger-Publikation in Arbeit. Erst dann dürfen die bisher unbenutzen Daten untersucht werden. Fil: González, Nicolás Martín. Karlsruher Institut für Technologie; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Tecnología en Detección y Astropartículas. Comisión Nacional de Energía Atómica. Instituto de Tecnología en Detección y Astropartículas. Universidad Nacional de San Martín. Instituto de Tecnología en Detección y Astropartículas; Argentina. Universidad Nacional de San Martín; Argentina

The CosmicWatch Desktop Muon Detector is a self-contained, hand-held cosmic ray muon detector that is valuable for astro/particle physics research applications and outreach. The material cost of each detector is under $100 and it takes a novice student approximately four hours to build their first detector. The detectors are powered via a USB connection and the data can either be recorded directly to a computer or to a microSD card. Arduino- and Python-based software is provided to operate the detector and an online application to plot the data in real-time. In this paper, we describe the various design features, evaluate the performance, and illustrate the detectors capabilities by providing several example measurements. KEYWORDS: CosmicWatch; Desktop Muon Detector; cosmic rays; muons; outreach, National Science Foundation (U.S.) (Grant NSF-PHY-1505858), Poland. National Science Centre (2015/17/N/ST2/04064), MIT Seed Fund

Early results of the search for E_\gamma>1 PeV cosmic photons from point sources with the data of Carpet-2, an air-shower array equipped with a 175 m^2 muon detector, are presented. They include 95% CL upper limits on PeV photon fluxes from stacked directions of high-energy IceCube neutrino events and from four predefined sources, Crab, Cyg X-3, Mrk 421 and Mrk 501. An insignificant excess of events from Mrk 421 will be further monitored. Prospects of the use of the upgraded installation, Carpet-3 (410 m^2 muon detector), scheduled to start data taking in 2019, for searches of E_\gamma>100 TeV photons, are briefly discussed., Comment: 5 pages, 2 figures, webofc style. Presented at the VLVNT-2018 workshop, Dubna, October 2-4, 2018. V2: minor copy-editing changes

The nSYNC chip is a radiation tolerant custom ASIC, developed in UMC 130 nm technology, and the main component of the new readout electronics for the LHCb Muon Detector Upgrade. The nSYNC has been developed in order to implement all the required functionalities for the readout upgrade in terms of timing alignment and measurements, and equipped also with control and monitoring features. The internal architecture of the chip, the data flow and test results on different nSYNC functionalities are presented.

The temperature effect of high mountain muon detectors, which exceeds the theoretically expected one, is investigated. The inverse instrument problem for experimental determination of the density of the temperature coefficient is solved. Results provided by the mddb database created for muon detectors are used as observational data and briefly described.

The new detecting system of the Cherenkov water detector of the Unique Scientific Facility “Experimental complex NEVOD” located at the ground level is described. During the development of the detecting system, two tasks have been solved: providing a hodoscopic mode for registration of single muon tracks in 4π-geometry and a calorimetric mode for measurements of the energy deposit of cascades and high-multiplicity muon bundles.

The upgrades of the LHC planned in the next years will increase the instantaneous luminosity up to $5 \times 10^{34}$ cm$^{-2}$s$^{-1}$ after Long Shutdown 3, a value about five times higher than the nominal one for which the CMS experiment was designed. The resulting larger rate of interactions will produce a higher pileup environment that will challenge the trigger system of the CMS experiment in its original configuration, in particular in the endcap region. As part of the upgrade program of the CMS muon endcaps, additional muon detectors based on Gas Electron Multiplier (GEM) technology will be installed, in order to be able to sustain a physics program during high-luminosity operation without performance losses. The installation of the GE1/1 station is scheduled for Long Shutdown 2 in 2019-2020; already a demonstrator composed of five superchambers has been installed during the Extended Year-End Technical Stop at the beginning of 2017. Its goal is to test the systems operational conditions and also to demonstrate the integration of the GE1/1 chambers into the CMS online system. The status of the installation and commissioning of the GE1/1 demonstrator is presented.

Researchers have used muon detectors to discover a mysterious, 30-metre-long space — which could help to reveal how the 4,500-year-old monument was built.

This paper describes the construction of a desktop muon detector, an undergraduate-level physics project that develops machine-shop and electronics-shop technical skills. The desktop muon detector is a self-contained apparatus that employs a plastic scintillator as the detection medium and a silicon photomultiplier for light collection. This detector can be battery powered and is used in conjunction with the provided software. The total cost per detector is approximately $100. We describe physics experiments we have performed, and then suggest several other interesting measurements that are possible, with one or more desktop muon detectors., National Science Foundation (U.S.) (Grant 1505858)

We built a large (approximately 4,000 m**2) water Cherenkov- type muon detector array under the existing Tibet air shower array at 4,300 m above sea level, to observe 10-1000 TeV gamma rays from cosmic-ray accelerators in our Galaxy with wide field of view at very low background level. A gamma-ray induced air shower has significantly less muons compared with a cosmic-ray induced one. Therefore, we can effectively discriminate between primary gamma rays and cosmic-ray background events by means of counting number of muons in an air shower event by the muon detector array. We make a status report on the experiment.

In the Large High Altitude Air Shower Observatory project, Muon detectors will be built at 4400m above sea level. As water cerenkov detector, 44 tons of ultrapure water should be infused into the Muon detector. In this cold area, once the water inside the Muon detector freezes, consequence would be very serious. In this paper, a simulation of water temperature is built, the simulation data are consistent with the temperature data of Muon detector at yangbajing Tibet. Using the same simulation with air temperature, soil moisture and temperature of Dao cheng, an antifreeze solution was designed. Through two years of testing, the design is successful.

On 2017 January 18 scaler rates in the IceTop detectors at the South Pole revealed an impulsive increase in the galactic cosmic ray flux lasting a few hours. In addition to the neutron monitor at Pole the event was detected clearly by the Mawson neutron monitor and faintly at Jang Bogo. No other neutron monitors appear to have seen the increase. The event was in many ways reminiscent of the 2015 June 22 event observed by the GRAPES muon detectors. Both events occurred during the declining phase of a Forbush decrease, at a time of increasing geomagnetic activity, and were observed by a limited number of neutron monitors with similar asymptotic directions. The magnitude of the impulse was in both cases such that the flux returned briefly to approximately the pre-decrease level. Distinctly unlike the 2015 June 22 event, a changing geomagnetic cutoff cannot explain the 2017 January 18 event because the cutoff at South Pole is nearly zero and the detector response is atmosphere limited. We therefore interpret the 2017 January 18 event in terms of the structure of the Forbush decrease and (possibly changing) asymptotic directions. With our interpretation of the January event in mind we also comment on possible alternative interpretations of the GRAPES event.

The Large High Altitude Air Shower Observatory (LHAASO) will be constructed at 4400 m asl in Daocheng, Sichuan Province, with the aim of discovering sources of ultra-high energy cosmic rays and studying cosmic ray physics. The whole array includes 1171 muon detectors (MDs), constituting the largest muon detector array in the world. The special high altitude and wide-field environment requires simple and stable calibration as well as monitoring method of MDs. In this paper, the muon decay events will be selected for calibrating the charge and monitoring the water level of each MD. In the prototype muon detector, the simulation and experiment results reveal that the charge of the decay electron is approximately 0.147 times that of the vertical equivalent muon for a standard MD, and the QVEM/Qe shows a linear correlation with the water level.

Solar disturbances modulate cosmic rays on different time scales. Studying cosmic ray variation is an important subject that attracts scientists from different disciplines. In this study, correlation analyses between cosmic ray muons and both the solar wind speed and sunspot number for the period between 2002 and 2012 have been conducted. Cosmic ray data were obtained from the KACST muon detector in Riyadh, Saudi Arabia (24 43; 46 40; Rc =14.4 GV). We have found that cosmic ray muons are anti-correlated with both parameters. The same analyses have been carried out using data from the Oulu neutron monitor and comparable results with the KACST detector have been found.

In this study, the relationship between cosmic ray muons and the atmospheric temperature in the lower stratosphere has been investigated and established. Cosmic ray data from the KACST muon detector (Rc= 14.4 GV) and radiosonde measurements from Riyadh airport, for the period 2002–2012, have been used for this purpose. We have found that the temperature in the lower stratosphere is correlated with the cosmic ray muons detected at ground level. The results obtained are in agreement with previous studies. The technique was then used to predict temperature variations in the lower stratosphere. It was found that the temperature can be reproduced with a mean bias error of 0.5 °C and a root mean square error of 3 °C.

The Tibet-ASgamma experiment has a water-Cherenkov muon-detector array (MD) as a part of 3 different arrays with specific purposes. To increase the ability of getting the primary proton, helium and iron spectra up to 10^16 eV and clarifing their spectral "knee" positions, we need to upgrade current PMT capabiltty in each MD cell. The current dynamic range of the PMTs is 5 to 2000 photoelectrons (PEs) which is enough for the purpose of observation of high-energy celestial gamma rays. However, according to Monte-Carlo simulations, we need a dynamic range of 100 - 10^6 PEs for the knee problem. For this end, we have a plan of adding two 8-inch-in-diameter PMTs in each MD cell. We have compared the characteristic features between R5912-PMT made by Japan Hamamatsu and CR365-PMT made by Beijing Hamamatsu, and found that CR365-PMT fulfill our requirements. In this paper, test results of the first batch of 20 CR365-PMTs made by Beijing Hamamatsu for the MD array are shown.

The ALPACA experiment is a new project aimed at wide field-of-view high-sensitivity observations of high-energy cosmic rays and cosmic gamma rays, launched between Bolivia and Japan in 2016. It is composed of an 83,000 m$^2$ air shower array and a 5,400 m$^2$ underground muon detector array, on a highland at the altitude of 4,740 m, halfway up Mount Chacaltaya on the outskirts of La Paz, Bolivia.

The design of a simple, inexpensive cosmic-ray-muon detector has led to an international outreach program.

The CMS muon system has played a key role for many physics results obtained from the LHC Run1 and Run2 data. During the Long Shutdown (2013-2014), as well as during the last year-end technical stop (2015-2016), significant consolidation and upgrades have been carried out on the muon detectors and on the Level-1 (L1) muon trigger. The algorithms for muon reconstruction and identification have also been improved for both the High-Level Trigger (HLT) and the offline reconstruction. Results of the performance of muon detectors, reconstruction and trigger, obtained using data collected at 13 TeV center-of-mass energy during the 2015 and 2016 LHC runs, are presented. Comparison of simulation with experimental data is also discussed where relevant. The system's state of the art is also shown, as well the improvements foreseen to achieve excellent overall quality of muon reconstruction in the high-luminosity conditions expected during Run2.

The CMS detector currently includes three different muon detector types: drift tubes (DT) in the central region, cathode strip chambers (CSC) in the forward regions, and resistive plate chambers (RPC) in both the forward and central regions. Several upgrade projects are planned to maintain high data-taking efficiency with the planned running conditions for the high-luminosity upgrade of the LHC. These upgrades are designed to ensure detector longevity and increase redundancy, while mitigating rate increases and retaining sensitivity to phyics processes. This involves changes to electronics and infrastructure of existing detectors, and adding new detectors in the forward region of the CMS experiment. Plans for each of the muon subsystems are described here in the context of the Phase-II upgrade schedule of the CMS experiment.