22 results on '"Povolo, L."'
Search Results
2. Systematic characterization of a Ne, Ar, Kr rare-gas moderated positron beam and spin polarization measurements
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Povolo, L., Mariazzi, S., Bettonte, M., Penasa, L., Caravita, R., and Brusa, R.S.
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- 2024
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3. Feasibility studies for imaging [formula omitted] annihilation with modular multi-strip detectors
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Sharma, S., Povolo, L., Mariazzi, S., Korcyl, G., Kacprzak, K., Kumar, D., Niedźwiecki, S., Baran, J., Beyene, E., Brusa, R.S., Caravita, R., Chug, N., Coussat, A., Curceanu, C., Czerwinski, E., Dadgar, M., Das, M., Dulski, K., Eliyan, K., Gajos, A., Gupta, N., Hiesmayr, B.C., Kapłon, Ł., Kaplanoglu, T., Klimaszewski, K., Konieczka, P., Kozik, T., Kozani, M.K., Krzemień, W., Moyo, S., Mryka, W., Penasa, L., Parzych, S., Rio, E. Perez. Del, Raczyński, L., Shivani, Shopa, R.Y., Skurzok, M., Stępień, E.Ł., Tanty, P., Tayefi, F., Tayefi, K., Wiślicki, W., and Moskal, P.
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- 2024
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4. Method for measuring positron number in high intensity nanosecond positron bunches based on Poisson statistic
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Rienäcker, B., Mariazzi, S., Povolo, L., Guatieri, F., Caravita, R., Penasa, L., Pino, F., Nebbia, G., and Brusa, R.S.
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- 2022
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5. Pulsed Production of Antihydrogen in AEgIS
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Zurlo N., Auzins M., Bergmann B., Bonomi G., Brusa R.S., Burian P., Camper A., Castelli F., Ciury R., Consolati G., Doser M., Farricker A., Glöggler L., Graczykowski Ł., Grosbart M., Guatieri F., Gusakova N., Haider S., Huck S., Janik M., Kasprowicz G., Khatri G., Kłosowski Ł., Kornakov G., Krumins V., Lappo L., Linek A., Malamant J., Malbrunot C., Mariazzi S., Nowak L., Nowicka D., Oswald E., Pagano D., Penasa L., Piwiński M., Pospisil S., Povolo L., Prelz F., Rangwala S., Rienäcker B., Røhne O.M., Rotondi A., Sandaker H., Smolyanskiy P., Sowiński T., Tefelski D., Testera G., Volponi M., Welsch C.P., Wolz T., Zawada M., and Zielinski J.
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Physics ,QC1-999 - Abstract
Low-temperature antihydrogen atoms are an effective tool to probe the validity of the fundamental laws of Physics, for example the Weak Equivalence Principle (WEP) for antimatter, and -generally speaking- it is obvious that colder atoms will increase the level of precision. After the first production of cold antihydrogen in 2002 [1], experimental efforts have substantially progressed, with really competitive results already reached by adapting to cold antiatoms some well-known techniques pre- viously developed for ordinary atoms. Unfortunately, the number of antihydrogen atoms that can be produced in dedicated experiments is many orders of magnitude smaller than of hydrogen atoms, so the development of novel techniques to enhance the production of antihydrogen with well defined (and possibly controlled) conditions is essential to improve the sensitivity. We present here some experimental results achieved by the AEgIS Collaboration, based at the CERN AD (Antiproton Decelerator) on the production of antihydrogen in a pulsed mode where the production time of 90% of atoms is known with an uncertainty of ~ 250 ns [2]. The pulsed antihydrogen source is generated by the charge-exchange reaction between Rydberg positronium (Ps*) and an antiproton (p¯): p¯ + Ps* → H¯* + e−, where Ps* is produced via the implantation of a pulsed positron beam into a mesoporous silica target, and excited by two consecutive laser pulses, and antiprotons are trapped, cooled and manipulated in Penning-Malmberg traps. The pulsed production (which is a major milestone for AEgIS) makes it possible to select the antihydrogen axial temperature and opens the door for the tuning of the antihydrogen Rydberg states, their de-excitation by pulsed lasers and the manipulation through electric field gradients. In this paper, we present the results achieved by AEgIS in 2018, just before the Long Shutdown 2 (LS2), as well as some of the ongoing improvements to the system, aimed at exploiting the lower energy antiproton beam from ELENA [3].
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- 2023
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6. A low cost 2/3 of 4[formula omitted] detector for the study of Ps decay
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Pino, F., Fontana, C.L., Lunardon, M., Moretto, S., Stevanato, L., Brusa, R., Caravita, R., Mariazzi, S., Penasa, L., Povolo, L., and Nebbia, G.
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- 2019
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7. Characterization of a transmission positron/positronium converter for antihydrogen production
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Aghion, S., Amsler, C., Ariga, T., Bonomi, G., Brusa, R.S., Caccia, M., Caravita, R., Castelli, F., Cerchiari, G., Comparat, D., Consolati, G., Demetrio, A., Di Noto, L., Doser, M., Ereditato, A., Evans, C., Ferragut, R., Fesel, J., Fontana, A., Gerber, S., Giammarchi, M., Gligorova, A., Guatieri, F., Haider, S., Hinterberger, A., Holmestad, H., Kellerbauer, A., Krasnický, D., Lagomarsino, V., Lansonneur, P., Lebrun, P., Malbrunot, C., Mariazzi, S., Matveev, V., Mazzotta, Z., Müller, S.R., Nebbia, G., Nedelec, P., Oberthaler, M., Pacifico, N., Pagano, D., Penasa, L., Petracek, V., Povolo, L., Prelz, F., Prevedelli, M., Ravelli, L., Resch, L., Rienäcker, B., Robert, J., Røhne, O.M., Rotondi, A., Sacerdoti, M., Sandaker, H., Santoro, R., Scampoli, P., Simon, M., Smestad, L., Sorrentino, F., Testera, G., Tietje, I.C., Widmann, E., Yzombard, P., Zimmer, C., Zmeskal, J., Zurlo, N., Andersen, S.L., Chevallier, J., Uggerhøj, U.I., and Lyckegaard, F.
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- 2017
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8. J-PET detection modules based on plastic scintillators for performing studies with positron and positronium beams
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Sharma, S., Baran, J., Brusa, R. S., Caravita, R., Chug, N., Coussat, A., Curceanu, C., Czerwinski, E., Dadgar, M., Dulski, K., Eliyan, K., Gajos, A., Hiesmayr, B. C., Kacprzak, K., Kaplon, L., Klimaszewski, K., Konieczka, P., Korcyl, G., Kozik, T., Krzemien, W., Kumar, D., Mariazzi, S., Niedzwiecki, S., Panasa, L., Parzych, S., Povolo, L., del Rio, E. Perez, Raczynski, L., Shivani, Shopa, R. Y., Skurzok, M., Stepien, E. L., Tayefi, F., Tayefi, K., Wislicki, W., and Moskal, P.
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Physics - Instrumentation and Detectors ,gamma detectors ,FOS: Physical sciences ,Instrumentation and Detectors (physics.ins-det) ,multi-modality systems ,interferometry ,Instrumentation ,Mathematical Physics - Abstract
The J-PET detector, which consists of inexpensive plastic scintillators, has demonstrated its potential in the study of fundamental physics. In recent years, a prototype with 192 plastic scintillators arranged in 3 layers has been optimized for the study of positronium decays. This allows performing precision tests of discrete symmetries (C, P, T) in the decays of positronium atoms. Moreover, thanks to the possibility of measuring the polarization direction of the photon based on Compton scattering, the predicted entanglement between the linear polarization of annihilation photons in positronium decays can also be studied. Recently, a new J-PET prototype was commissioned, based on a modular design of detection units. Each module consists of 13 plastic scintillators and can be used as a stand-alone, compact and portable detection unit. In this paper, the main features of the J-PET detector, the modular prototype and their applications for possible studies with positron and positronium beams are discussed. Preliminary results of the first test experiment performed on two detection units in the continuous positron beam recently developed at the Antimatter Laboratory (AML) of Trento are also reported.
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- 2023
9. Development of a Position-Sensitive Detector for Positronium Inertial Sensing Measurements
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Mariazzi, S., Caravita, R., Glöggler, L., Povolo, L., Penasa, L., Sharma, Sushil, Moskal, Paweł, and Bruda, R. S.
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positronium ,antimatter ,General Physics and Astronomy ,spatial-sensitive detector ,Detectors and Experimental Techniques - Abstract
In the last twenty years, both free fall and interferometry/deflectometry experiments have been proposed for the measurement of the gravitational acceleration on positronium, which is a purely leptonic matter-antimatter atom formed by an electron and its antiparticle (positron). Among the several challenges posed by these experiments is the development of position-sensitive detectors to measure the deflection of positronium in the Earth's gravitational field. In this work, we describe our recent progress in the development of position-sensitive detectors. Two different detection schemes are considered. The first is based on Ps ionization in a strong homogeneous magnetic field and imaging of the freed positron with a microchannel plate. The second scheme is based on scanning the positronium atom distribution on a plane by moving the slit or a material grating with sub-nm accuracy, and counting the atoms crossing the obstacle and those annihilating on it. The possibility of reaching a spatial resolution of around 15 μm using the former detection scheme is shown, and preliminary steps towards the development of a detector following the latter scheme (with potential position sensitivity in the sub-nm range) are described.
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- 2022
10. Development of a detector for inertial sensing of positronium at AEgIS (CERN)
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Glöggler, Lisa T., Caravita, R., Bergmann, B., Bonomi, G., Brusa, R. S., Burian, P., Camper, A., Castelli, F., Cheinet, P., Comparat, D., Consolati, G., Doser, M., Gjersdal, H., Graczykowski, Ł., Guatieri, F., Haider, S., Huck, S., Janik, M., Kasprowicz, G., Khatri, G., Kornakov, G., Malbrunot, C., Mariazzi, S., Nebbia, G., Nowak, L., Nowicka, D., Oswald, E., Pagano, D., Penasa, L., Pospisil, S., Povolo, L., Prelz, F., Rienäcker, B., Røhne, O. M., Sandaker, H., Stekl, I., Tefelski, D., Tietje, I. C., Volponi, M., Wolz, T., Zimmer, C., and Zurlo, N.
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History ,detector ,CERN ,positronium ,Detectors and Experimental Techniques ,530 Physik ,AEḡIS ,gravitational acceleration ,Computer Science Applications ,Education - Abstract
The primary goal of the AEgIS collaboration at CERN is to measure the gravitational acceleration on neutral antimatter. Positronium (Ps), the bound state of an electron and a positron, is a suitable candidate for a force-sensitive inertial measurement by means of deflectometry/interferometry. In order to conduct such an experiment, the impact position and time of arrival of Ps atoms at the detector must be detected simultaneously. The detection of a low-velocity Ps beam with a spatial resolution of (88 ± 5) μm was previously demonstrated [1]. Based on the methodology employed in [1] and [2], a hybrid imaging/timing detector with increased spatial resolution of about 10 μm was developed. The performance of a prototype was tested with a positron beam. The concept of the detector and first results are presented.
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- 2022
11. Experiments with mid-heavy antiprotonic atoms in AE$\overline{g}$IS
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Kornakov, G, Auzins, M, Bergmann, B, Burian, P, Bonomi, G, Brusa, R S, Camper, A, Caravita, R, Castelli, F, Cheinet, P, Ciuryło, R, Comparat, D, Consolati, G, Doser, M, Gjersdal, H, Glöggler, L T, Graczykowsk, Ł, Guatieri, F, Haider, S, Huck, S, Janik, M, Kasprowicz, G, Khatri, G, Kłosowski, Ł, Lappo, L, Malbrunot, C, Mariazzi, S, Nebbia, G, Nowak, L, Nowicka, D, Oswald, E, Pagano, D, Penasa, L, Petracek, V, Piwiński, M, Pospisil, S, Povolo, L, Prelz, F, Rangwala, S, Rienäcker, B, Rotondi, A, Røhne, O M, Sandaker, H, Stekl, I, Tefelski, D, Tietje, I C, Volponi, M, Wolz, T, Zawada, M, Zimmer, C, and Zurlo, N
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Nuclear Physics - Experiment - Abstract
ments which provide the most precise data on the strong interaction between protons and antiprotons and of the neutron skin of many nuclei thanks to the clean annihilation signal. In most of these experiments, the capture process of low energy antiprotons was done in a dense target leading to a significant suppression of specific transitions between deeply bound levels that are of particular interest. In particular, precise measurements of specific transitions in antiprotonic atoms with Z>2 are sparse. We propose to use the pulsed production scheme developed for antihydrogen and protonium for the formation of cold antiprotonic atoms. This technique has been recently achieved experimentally for the production of antihydrogen at AE$\overline{\rm g}$IS. The proposed experiments will have sub-ns synchronization thanks to an improved control and acquisition system. The formation in vacuum guarantees the absence of Stark mixing or annihilation from high n states and together with the sub-ns synchronization would resolve the previous experimental limitations. It will be possible to access the whole chain of the evolution of the system from its formation until annihilation with significantly improved signal-to-background ratio.
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- 2022
12. Pulsed Production of Antihydrogen in AEgIS
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Zurlo, N., Amsler, C., Antonello, M., Belov, A., Bonomi, G., Brusa, R. S., Caccia, M., Camper, A., Caravita, R., Castelli, F., Cheinet, P., Comparat, D., Consolati, G., Demetrio, A., Di Noto, L., Doser, M., Fani, M., Ferragut, R., Fesel, J., Gerber, S., Giammarchi, M., Gligorova, A., Gloggler, L. T., Guatieri, F., Haider, S., Hinterberger, A., Kellerbauer, A., Khalidova, O., Krasnicky, D., Lagomarsino, V., Malbrunot, C., Mariazzi, S., Matveev, V., Muller, R., Nebbia, G., Nedelec, P., Nowak, L., Oberthaler, M., Oswald, E., Pagano, D., Penasa, L., Petracek, V., Povolo, L., Prelz, F., Prevedelli, M., Rienacker, B., Rohne, O. M., Rotondi, A., Sandaker, H., Santoro, R., Testera, G., Tietje, I. C., Toso, V., Wolz, T., Yzombard, P., and Zimmer, C.
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Antihydrogen ,antiprotons ,Accelerators and Storage Rings ,Antihydrogen, antiprotons - Abstract
Cold antihydrogen atoms are a powerful tool to probe the validity of fundamental physics laws, and it's clear that colder atoms, generally speaking, allow an increased level of precision. After the first production of cold antihydrogen ($\bar{H}$) in 2002, experimental efforts have progressed continuously (trapping, beam formation, spectroscopy), with competitive results already achieved by adapting to cold antiatoms techniques previously well developed for ordinary atoms. Unfortunately, the number of $\bar{H}$ atoms that can be produced in dedicated experiments is many orders of magnitude smaller than available hydrogen atoms, which are at hand in large amount, so the development of novel techniques that allow the production of $\bar{H}$ with well defined conditions (and possibly control its formation time and energy levels) is essential to improve the sensitivity of the methods applied by the different experiments. We present here the first experimental results concerning the production of $\bar{H}$ in a pulsed mode where the time when 90\% of the atoms are produced is known with an uncertainty of around 250~ns. The pulsed $\bar{H}$ source is generated by the charge-exchange reaction between Rydberg positronium atoms ($Ps$) and trapped antiprotons ($\bar{p}$), cooled and manipulated in an electromagnetic trap: $$ \bar{ p}+Ps^* \rightarrow \bar{H}^* + e^- $$ where Rydberg positronium atoms, in turn, are produced through the implantation of a pulsed positron beam into a mesoporous silica target, and are excited by two subsequent laser pulses, the first to $n=3$, the second to the needed Rydberg level ($n \simeq 17$). The pulsed production allows the control of the antihydrogen temperature, and facilitates the tunability of the Rydberg states, their de-excitation by pulsed lasers and the manipulation through electric field gradients. In fact, the production of pulsed antihydrogen is a major milestone in the AEgIS experiment to perform direct measurements of the validity of the Weak Equivalence Principle for antimatter.
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- 2022
13. Protocol for pulsed antihydrogen production in the AE$\overline{g}$IS apparatus
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Tietje, I.C., Amsler, C., Antonello, M., Belov, A., Bonomi, G., Brusa, R.S., Caccia, M., Camper, A., Caravita, R., Castelli, F., Cheinet, P., Comparat, D., Consolati, G., Demetrio, A., Noto, L.Di, Doser, M., Fanì, M., Ferragut, R., Fesel, J., Gerber, S., Giammarchi, M., Gligorova, A., Glöggler, L.T., Guatieri, F., Haider, S., Hinterberger, A., Kellerbauer, A., Khalidova, O., Krasnický, D., Lagomarsino, V., Malbrunot, C., Nowak, L., Mariazzi, S., Matveev, V., Müller, S.R., Nebbia, G., Nedelec, P., Oberthaler, M., Oswald, E., Pagano, D., Penasa, L., Petracek, V., Povolo, L., Prelz, F., Prevedelli, M., Rienäcker, B., Røhne, O.M., Rotondi, A., Sandaker, H., Santoro, R., Testera, G., Toso, V., Wolz, T., Yzombard, P., Zimmer, C., Zurlo, N., Laboratoire Aimé Cotton (LAC), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École normale supérieure - Cachan (ENS Cachan), Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)
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velocity ,experimental methods ,antihydrogen: production ,deflection ,gravitation: acceleration ,[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex] ,beam: pulsed ,anti-p: acceleration ,time-of-flight ,talk ,anti-p p: annihilation ,antihydrogen: acceleration ,Particle Physics - Experiment - Abstract
International audience; The AEḡIS collaboration’s main goal is to measure the acceleration of antihydrogen it ($\textit{H}$) due to gravity. The experimental scheme is to form a pulsed beam whose vertical deflection is then measured by means of a moiré deflectometer [1]. Creating pulsed $\textit{H}$is crucial since it allows a velocity measurement of the antiatoms via time of flight ($\mathrm{ToF}$) necessary to deduce the gravitational acceleration ḡ from the vertical deflection $\Delta\mathit{s}$. The aim of this article is to outline the experimental protocol leading up to pulsed antihydrogen production in the AEḡIS experiment.
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- 2020
14. Developments for pulsed antihydrogen production towards direct gravitational measurement on antimatter
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Alberto Rotondi, S. Müller, G. Nebbia, Davide Pagano, O. Khalidova, Massimo Caccia, L. Povolo, Giovanni Consolati, V. Toso, Germano Bonomi, Heidi Sandaker, V. Petráček, A. Hinterberger, L. T. Glöggler, Sebastiano Mariazzi, B. Rienäcker, C. Zimmer, L. Di Noto, Marco Giammarchi, Marco Prevedelli, M. Antonello, Chloé Malbrunot, G. Testera, Angela Gligorova, Ole Røhne, Nicola Zurlo, Sebastian Gerber, Fabrizio Castelli, Alban Kellerbauer, A. S. Belov, I. C. Tietje, D. Krasnicky, V. Lagomarsino, M. Fanì, L. Nowak, Romualdo Santoro, Michael Doser, Patrick Nedelec, E. Oswald, J. Fesel, V. Matveev, S. Haider, P. Cheinet, A. Demetrio, F. Guatieri, Luca Penasa, A. Camper, F. Prelz, Daniel Comparat, Ruggero Caravita, T. Wolz, Markus K. Oberthaler, R. S. Brusa, Rafael Ferragut, Fani M., Antonello M., Belov A., Bonomi G., Brusa R.S., Caccia M., Camper A., Caravita R., Castelli F., Comparat D., Cheinet P., Consolati G., Demetrio A., Di Noto L., Doser M., Ferragut R., Fesel J., Gerber S., Giammarchi M., Gligorova A., Gloggler L.T., Guatieri F., Haider S., Hinterberger A., Kellerbauer A., Khalidova O., Krasnicky D., Lagomarsino V., Malbrunot C., Nowak L., Mariazzi S., Matveev V., Muller S.R., Nebbia G., Nedelec P., Oberthaler M., Oswald E., Pagano D., Penasa L., Petracek V., Povolo L., Prelz F., Prevedelli M., Rienacker B., Rohne O.M., Rotondi A., Sandaker H., Santoro R., Testera G., Tietje I.C., Toso V., Wolz T., Zimmer C., Zurlo N., Laboratoire Aimé Cotton (LAC), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École normale supérieure - Cachan (ENS Cachan), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)
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Gravity (chemistry) ,Physics::General Physics ,Antimatter ,experimental methods ,Gravity ,Antiproton ,magnetic field ,Positronium ,01 natural sciences ,010305 fluids & plasmas ,Nuclear physics ,Gravitation ,temperature: low ,0103 physical sciences ,general relativity ,[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex] ,Physics::Atomic and Molecular Clusters ,Physics::Atomic Physics ,010306 general physics ,Antihydrogen ,Mathematical Physics ,Physics ,gravitation: interaction ,antihydrogen: production ,talk: Kolymbari 2019/08/21 ,sensitivity ,charge exchange ,Condensed Matter Physics ,pulsed ,Atomic and Molecular Physics, and Optics ,anti-p ,equivalence principle ,gravitation: acceleration ,gravitation: local ,experimental results - Abstract
International audience; A main scientific goal of the experiment is the direct measurement of the Earth’s local gravitational acceleration g on antihydrogen. The Weak Equivalence Principle is a foundation of General Relativity. It has been extensively tested with ordinary matter but very little is known about the gravitational interaction between matter and antimatter. Antihydrogen is produced in via resonant charge-exchange reaction between cold Rydberg-excited positronium and cooled down antiprotons. The achievements for the development of a pulsed cold antihydrogen source are presented. Large number of antiprotons, necessary for a significant production rate of antihydrogen, are captured, accumulated, compressed and cooled over an extended period of time. Positronium (Ps) is formed through e$^{+}$-Ps conversion in a silica porous target at 10 K temperature in a reflection geometry inside the main apparatus. The so-formed Ps cloud is then laser-excited to Rydberg levels, for the first time in a 1 T magnetic field. Consequently, a detailed characterization of the Ps source for antihydrogen production in magnetic field needed to be performed. Several detection techniques are extensively used to monitor antiproton and positron manipulations in the formation process of antihydrogen inside the main apparatus. Positronium detection techniques underwent extensive improvements in sensitivity during the last antiproton run. At the same time, major efforts to improve integrate and commission the detectors sensitive to antihydrogen production took place.
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- 2020
15. Characterization of a transmission positron/positronium converter for antihydrogen production
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Victor Matveev, Paola Scampoli, Tomoko Ariga, Ulrik I. Uggerhøj, S. Haider, Claude Amsler, S.R. Müller, G. Nebbia, J. Fesel, Ole Røhne, B. Rienäcker, Roberto S. Brusa, Z. Mazzotta, G. Testera, Eberhard Widmann, Rafael Ferragut, V. Petracek, Giovanni Cerchiari, Felice Sorrentino, Romualdo Santoro, V. Lagomarsino, Alban Kellerbauer, L. Resch, S.L. Andersen, N. Pacifico, Luca Penasa, F. Lyckegaard, F. Prelz, Fabrizio Castelli, Stefano Aghion, J. Robert, D. Krasnický, A. Demetrio, Sebastiano Mariazzi, C. Evans, L. Ravelli, L. Di Noto, Michael Doser, Ruggero Caravita, Davide Pagano, P. Lebrun, C. Zimmer, Giovanni Consolati, Jacques Chevallier, Germano Bonomi, P. Lansonneur, Massimo Caccia, Sebastian Gerber, Marco Giammarchi, Daniel Comparat, Heidi Sandaker, Antonio Ereditato, M. Sacerdoti, M. C. Simon, F. Guatieri, Nicola Zurlo, Marco Prevedelli, H. Holmestad, L. Povolo, Chloé Malbrunot, I. C. Tietje, Adriano Fontana, Alberto Rotondi, A. Hinterberger, L. Smestad, Patrick Nedelec, Johann Zmeskal, M. Oberthaler, Angela Gligorova, P. Yzombard, Université Paris-Sud - Paris 11 (UP11), Laboratoire Aimé Cotton (LAC), École normale supérieure - Cachan (ENS Cachan)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Aghion, S., Amsler, C., Ariga, T., Bonomi, G., Brusa, R.S., Caccia, M., Caravita, R., Castelli, F., Cerchiari, G., Comparat, D., Consolati, G., Demetrio, A., Di Noto, L., Doser, M., Ereditato, A., Evans, C., Ferragut, R., Fesel, J., Fontana, A., Gerber, S., Giammarchi, M., Gligorova, A., Guatieri, F., Haider, S., Hinterberger, A., Holmestad, H., Kellerbauer, A., Krasnický, D., Lagomarsino, V., Lansonneur, P., Lebrun, P., Malbrunot, C., Mariazzi, S., Matveev, V., Mazzotta, Z., Müller, S.R., Nebbia, G., Nedelec, P., Oberthaler, M., Pacifico, N., Pagano, D., Penasa, L., Petracek, V., Povolo, L., Prelz, F., Prevedelli, M., Ravelli, L., Resch, L., Rienäcker, B., Robert, J., Røhne, O.M., Rotondi, A., Sacerdoti, M., Sandaker, H., Santoro, R., Scampoli, P., Simon, M., Smestad, L., Sorrentino, F., Testera, G., Tietje, I.C., Widmann, E., Yzombard, P., Zimmer, C., Zmeskal, J., Zurlo, N., Andersen, S.L., Chevallier, J., Uggerhøj, U.I., Lyckegaard, F., Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École normale supérieure - Cachan (ENS Cachan), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Brusa, R. S., Müller, S. R., Røhne, O. M., Scampoli, Paola, Tietje, I. C., Andersen, S. L., and Uggerhøj, U. I.
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Photomultiplier ,COLLISIONS ,Positronium, Transmission, Antihydrogen ,Nuclear and High Energy Physics ,GRAPHITE ,Astrophysics::High Energy Astrophysical Phenomena ,BEAM ,[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex] ,Kinetic energy ,Positronium ,01 natural sciences ,Secondary electrons ,010305 fluids & plasmas ,SECONDARY-ELECTRON EMISSION ,Positron ,POSITRON-ANNIHILATION ,THIN-FILMS ,0103 physical sciences ,Transmission ,Antihydrogen ,mesa-structured silica ,010306 general physics ,COLD ,Instrumentation ,Physics ,PLASMA ,Scattering ,SURFACES ,positronium, mesa-structured silica ,TRANSPORT ,Time of flight ,Physics::Accelerator Physics ,Atomic physics - Abstract
In this work a characterization study of forward emission from a thin, meso-structured silica Received 17 March 2017 positron/positronium (Ps) converter following implantation of positrons in light of possible antihydrogen production is presented. The target consisted of a similar to 1 mu m thick ultraporous silica film e-gun evaporated onto a 20 nm carbon foil. The Ps formation and emission was studied via Single Shot Positron Annihilation Lifetime Spectroscopy measurements after implantation of pulses with 3 4.10(7) positrons and 10 ns temporal width. The forward emission of implanted positrons and secondary electrons was investigated with a micro-channel plate phosphor screen assembly, connected either to a CCD camera for imaging of the impinging particles, or to a fast photomultiplier tube to extract information about their time of flight. The maximum Ps formation fraction was estimated to be similar to 10%. At least 10% of the positrons implanted with an energy of 3.3 keV are forward-emitted with a scattering angle smaller than 50 and maximum kinetic energy of 1.2 keV. At least 0.1-0.2 secondary electrons per implanted positron were also found to be forward-emitted with a kinetic energy of a few eV. The possible application of this kind of positron/positronium converter for antihydrogen production is discussed. (C) 2017 Elsevier B.V. All rights reserved.
- Published
- 2017
16. Global View of Domain-Specific O-Linked Mannose Glycosylation in Glycoengineered Cells.
- Author
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Povolo L, Tian W, Vakhrushev SY, and Halim A
- Subjects
- Humans, Glycosylation, Substrate Specificity, Glycoproteins metabolism, Proteomics methods, Cell Line, Glycosyltransferases metabolism, Glycosyltransferases genetics, Protein Processing, Post-Translational, Cell Engineering methods, Mannose metabolism
- Abstract
Protein O-linked mannose (O-Man) glycosylation is an evolutionary conserved posttranslational modification that fulfills important biological roles during embryonic development. Three nonredundant enzyme families, POMT1/POMT2, TMTC1-4, and TMEM260, selectively coordinate the initiation of protein O-Man glycosylation on distinct classes of transmembrane proteins, including α-dystroglycan, cadherins, and plexin receptors. However, a systematic investigation of their substrate specificities is lacking, in part due to the ubiquitous expression of O-Man glycosyltransferases in cells, which precludes analysis of pathway-specific O-Man glycosylation on a proteome-wide scale. Here, we apply a targeted workflow for membrane glycoproteomics across five human cell lines to extensively map O-Man substrates and genetically deconstruct O-Man initiation by individual and combinatorial knockout of O-Man glycosyltransferase genes. We established a human cell library for the analysis of substrate specificities of individual O-Man initiation pathways by quantitative glycoproteomics. Our results identify 180 O-Man glycoproteins, demonstrate new protein targets for the POMT1/POMT2 pathway, and show that TMTC1-4 and TMEM260 pathways widely target distinct Ig-like protein domains of plasma membrane proteins involved in cell-cell and cell-extracellular matrix interactions. The identification of O-Man on Ig-like folds adds further knowledge on the emerging concept of domain-specific O-Man glycosylation which opens for functional studies of O-Man-glycosylated adhesion molecules and receptors., Competing Interests: Conflict of interest The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2024
- Full Text
- View/download PDF
17. Using automated software evaluation to improve the performance of breast radiographers in tomosynthesis screening.
- Author
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Gennaro G, Povolo L, Del Genio S, Ciampani L, Fasoli C, Carlevaris P, Petrioli M, Masiero T, Maggetto F, and Caumo F
- Subjects
- Humans, Female, Retrospective Studies, Longitudinal Studies, Patient Positioning methods, Clinical Competence, Prospective Studies, Software, Mammography methods, Breast Neoplasms diagnostic imaging
- Abstract
Objective: To improve breast radiographers' individual performance by using automated software to assess the correctness of breast positioning and compression in tomosynthesis screening., Materials and Methods: In this retrospective longitudinal analysis of prospective cohorts, six breast radiographers with varying experience in the field were asked to use automated software to improve their performance in breast compression and positioning. The software tool automatically analyzes craniocaudal (CC) and mediolateral oblique (MLO) views for their positioning quality by scoring them according to PGMI classifications (perfect, good, moderate, inadequate) and checking whether the compression pressure is within the target range. The positioning and compression data from the studies acquired before the start of the project were used as individual baselines, while the data obtained after the training were used to test whether conscious use of the software could help the radiographers improve their performance. The percentage of views rated perfect or good and the percentage of views in target compression were used as overall metrics to assess changes in performance., Results: Following the use of the software, all radiographers significantly increased the percentage of images rated as perfect or good in both CCs and MLOs. Individual improvements ranged from 7 to 14% for CC and 10 to 16% for MLO views. Moreover, most radiographers exhibited improved compression performance in CCs, with improvements up to 16%., Conclusion: Active use of a software tool to automatically assess the correctness of breast compression and positioning in breast cancer screening can improve the performance of radiographers., Clinical Relevance Statement: This study suggests that the use of a software tool for automatically evaluating correctness of breast compression and positioning in breast cancer screening can improve the performance of radiographers on these metrics, which may ultimately lead to improved screening outcomes., Key Points: • Proper breast positioning and compression are critical in breast cancer screening to ensure accurate diagnosis. • Active use of the software increased the quality of craniocaudal and mediolateral oblique views acquired by all radiographers. • Improved performance of radiographers is expected to improve screening outcomes., (© 2023. The Author(s).)
- Published
- 2024
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18. Positronium Laser Cooling via the 1^{3}S-2^{3}P Transition with a Broadband Laser Pulse.
- Author
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Glöggler LT, Gusakova N, Rienäcker B, Camper A, Caravita R, Huck S, Volponi M, Wolz T, Penasa L, Krumins V, Gustafsson FP, Comparat D, Auzins M, Bergmann B, Burian P, Brusa RS, Castelli F, Cerchiari G, Ciuryło R, Consolati G, Doser M, Graczykowski Ł, Grosbart M, Guatieri F, Haider S, Janik MA, Kasprowicz G, Khatri G, Kłosowski Ł, Kornakov G, Lappo L, Linek A, Malamant J, Mariazzi S, Petracek V, Piwiński M, Pospíšil S, Povolo L, Prelz F, Rangwala SA, Rauschendorfer T, Rawat BS, Rodin V, Røhne OM, Sandaker H, Smolyanskiy P, Sowiński T, Tefelski D, Vafeiadis T, Welsch CP, Zawada M, Zielinski J, and Zurlo N
- Abstract
We report on laser cooling of a large fraction of positronium (Ps) in free flight by strongly saturating the 1^{3}S-2^{3}P transition with a broadband, long-pulsed 243 nm alexandrite laser. The ground state Ps cloud is produced in a magnetic and electric field-free environment. We observe two different laser-induced effects. The first effect is an increase in the number of atoms in the ground state after the time Ps has spent in the long-lived 2^{3}P states. The second effect is one-dimensional Doppler cooling of Ps, reducing the cloud's temperature from 380(20) to 170(20) K. We demonstrate a 58(9)% increase in the fraction of Ps atoms with v_{1D}<3.7×10^{4} ms^{-1}.
- Published
- 2024
- Full Text
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19. Combination regimen of nirmatrelvir/ritonavir and molnupiravir for the treatment of persistent SARS-CoV-2 infection: A case report and a scoping review of the literature.
- Author
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Marangoni D, Antonello RM, Coppi M, Palazzo M, Nassi L, Streva N, Povolo L, Malentacchi F, Zammarchi L, Rossolini GM, Vannucchi AM, Bartoloni A, and Spinicci M
- Subjects
- Male, Humans, Aged, SARS-CoV-2, COVID-19 Drug Treatment, Antiviral Agents therapeutic use, Ritonavir therapeutic use, COVID-19
- Abstract
Immunocompromised patients still experience unpredictable courses of COVID-19, despite that effective vaccines and drugs against SARS-CoV-2 are now available. Antiviral combination regimens may have a role in SARS-CoV-2 infection in immunocompromised hosts, but current knowledge is still limited. We describe the case of a 73-year-old Italian man affected by follicular lymphoma with persistent SARS-CoV-2 infection who was successfully treated with co-administration of oral antivirals (10-day molnupiravir and nirmatrelvir/ritonavir). The therapy was well tolerated both from a clinical and biochemical standpoint, with no signs of toxicity. We also performed a scoping review, to sum up available knowledge on combined antiviral regimens including remdesivir, molnupiravir, or nirmatrelvir/ritonavir. Pending further studies on larger cohorts of patients, our report is consistent with available pre-clinical and clinical data, supporting the possible use of combination therapy in selected difficult-to-treat COVID-19 cases., Competing Interests: Declarations of competing interest The authors have no competing interests to declare., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2023
- Full Text
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20. The SHDRA syndrome-associated gene TMEM260 encodes a protein-specific O-mannosyltransferase.
- Author
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Larsen ISB, Povolo L, Zhou L, Tian W, Mygind KJ, Hintze J, Jiang C, Hartill V, Prescott K, Johnson CA, Mullegama SV, McConkie-Rosell A, McDonald M, Hansen L, Vakhrushev SY, Schjoldager KT, Clausen H, Worzfeld T, Joshi HJ, and Halim A
- Subjects
- Animals, Glycosylation, Mammals metabolism, Mannose metabolism, Mannosyltransferases genetics, Mannosyltransferases metabolism
- Abstract
Mutations in the TMEM260 gene cause structural heart defects and renal anomalies syndrome, but the function of the encoded protein remains unknown. We previously reported wide occurrence of O-mannose glycans on extracellular immunoglobulin, plexin, transcription factor (IPT) domains found in the hepatocyte growth factor receptor (cMET), macrophage-stimulating protein receptor (RON), and plexin receptors, and further demonstrated that two known protein O-mannosylation systems orchestrated by the POMT1/2 and transmembrane and tetratricopeptide repeat-containing proteins 1-4 gene families were not required for glycosylation of these IPT domains. Here, we report that the TMEM260 gene encodes an ER-located protein O-mannosyltransferase that selectively glycosylates IPT domains. We demonstrate that disease-causing TMEM260 mutations impair O-mannosylation of IPT domains and that TMEM260 knockout in cells results in receptor maturation defects and abnormal growth of 3D cell models. Thus, our study identifies the third protein-specific O-mannosylation pathway in mammals and demonstrates that O-mannosylation of IPT domains serves critical functions during epithelial morphogenesis. Our findings add a new glycosylation pathway and gene to a growing group of congenital disorders of glycosylation.
- Published
- 2023
- Full Text
- View/download PDF
21. A universal GlycoDesign for lysosomal replacement enzymes to improve circulation time and biodistribution.
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Chen YH, Tian W, Yasuda M, Ye Z, Song M, Mandel U, Kristensen C, Povolo L, Marques ARA, Čaval T, Heck AJR, Sampaio JL, Johannes L, Tsukimura T, Desnick R, Vakhrushev SY, Yang Z, and Clausen H
- Abstract
Currently available enzyme replacement therapies for lysosomal storage diseases are limited in their effectiveness due in part to short circulation times and suboptimal biodistribution of the therapeutic enzymes. We previously engineered Chinese hamster ovary (CHO) cells to produce α-galactosidase A (GLA) with various N-glycan structures and demonstrated that elimination of mannose-6-phosphate (M6P) and conversion to homogeneous sialylated N-glycans prolonged circulation time and improved biodistribution of the enzyme following a single-dose infusion into Fabry mice. Here, we confirmed these findings using repeated infusions of the glycoengineered GLA into Fabry mice and further tested whether this glycoengineering approach, Long-Acting-GlycoDesign (LAGD), could be implemented on other lysosomal enzymes. LAGD-engineered CHO cells stably expressing a panel of lysosomal enzymes [aspartylglucosamine (AGA), beta-glucuronidase (GUSB), cathepsin D (CTSD), tripeptidyl peptidase (TPP1), alpha-glucosidase (GAA) or iduronate 2-sulfatase (IDS)] successfully converted all M6P-containing N-glycans to complex sialylated N-glycans. The resulting homogenous glycodesigns enabled glycoprotein profiling by native mass spectrometry. Notably, LAGD extended the plasma half-life of all three enzymes tested (GLA, GUSB, AGA) in wildtype mice. LAGD may be widely applicable to lysosomal replacement enzymes to improve their circulatory stability and therapeutic efficacy., Competing Interests: A patent application has been filed by the University of Copenhagen. GlycoDisplay ApS has license rights to the patent application. ZY, WT, CK, and HC are named co-inventors, and ZY, CK, and HC have financial interests in GlycoDisplay ApS. Y-HC is an employee of GlycoDisplay ApS. RD is a Consultant to Genzyme-Sanofi and Sangamo Therapeutics, Inc. He owns founder stock in Amicus Therapeutics and options for Sangmo Therapeutics, Inc. and receives royalities from Genzyme-Sanofi. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Chen, Tian, Yasuda, Ye, Song, Mandel, Kristensen, Povolo, Marques, Čaval, Heck, Sampaio, Johannes, Tsukimura, Desnick, Vakhrushev, Yang and Clausen.)
- Published
- 2023
- Full Text
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22. A Bacterial Mannose Binding Lectin as a Tool for the Enrichment of C- and O-Mannosylated Peptides.
- Author
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Hütte HJ, Tiemann B, Shcherbakova A, Grote V, Hoffmann M, Povolo L, Lommel M, Strahl S, Vakhrushev SY, Rapp E, Buettner FFR, Halim A, Imberty A, and Bakker H
- Subjects
- Glycopeptides metabolism, Glycosylation, HEK293 Cells, Humans, Lectins chemistry, Burkholderia cenocepacia chemistry, Burkholderia cenocepacia metabolism, Mannose chemistry
- Abstract
Mass spectrometry (MS) easily detects C-mannosylated peptides from purified proteins but not from complex biological samples. Enrichment of specific glycopeptides by lectin affinity prior to MS analysis has been widely applied to support glycopeptide identification but was until now not available for C-mannosylated peptides. Here, we used the α-mannose-specific Burkholderia cenocepacia lectin A (BC2L-A) and show that, in addition to its previously demonstrated high-mannose N-glycan binding capability, this lectin is able to retain C- and O-mannosylated peptides. Besides testing binding abilities to standard peptides, we applied BC2L-A affinity to enrich C-mannosylated peptides from complex samples of tryptic digests of HEK293 and MCF10A whole cell extracts, which led to the identification of novel C-mannosylation sites. In conclusion, BC2L-A enabled specific enrichment of C- and O-mannosylated peptides and might have superior properties over other mannose binding lectins for this purpose.
- Published
- 2022
- Full Text
- View/download PDF
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