0000000000336249
AUTHOR
P. Pérez
A pulsed high-voltage decelerator system to deliver low-energy antiprotons
International audience; The GBAR (Gravitational Behavior of Antihydrogen at Rest) experiment at CERN requires efficient deceleration of 100 keV antiprotons provided by the new ELENA synchrotron ring to synthesize antihydrogen. This is accomplished using electrostatic deceleration optics and a drift tube that is designed to switch from -99 kV to ground when the antiproton bunch is inside – essentially a charged particle “elevator” – producing a 1 keV pulse. We describe the simulation, design, construction and successful testing of the decelerator device at -92 kV on-line with antiprotons from ELENA.
Positron production using a 9 MeV electron linac for the GBAR experiment
For the GBAR (Gravitational Behaviour of Antihydrogen at Rest) experiment at CERN's Antiproton Decelerator (AD) facility we have constructed a source of slow positrons, which uses a low-energy electron linear accelerator (linac). The driver linac produces electrons of 9 MeV kinetic energy that create positrons from bremsstrahlung-induced pair production. Staying below 10 MeV ensures no persistent radioactive activation in the target zone and that the radiation level outside the biological shield is safe for public access. An annealed tungsten-mesh assembly placed directly behind the target acts as a positron moderator. The system produces $5\times10^7$ slow positrons per second, a performan…
Utilidad de un nuevo sistema de cronometraje para proporcionar feedback inmediato a los nadadores
El presente documento tiene dos objetivos, en primer lugar, describir un nuevo sistema de cronometraje que proporciona feedback en tiempo real y sin interferir en la ejecución del nadador y, en segundo lugar, comprobar su utilidad. El sistema consiste en una pantalla de leds, resistente al agua e instalada en el fondo de la piscina, conectada a una Unidad Central mediante una plataforma de contacto colocada en la pared donde se realiza el viraje. La pantalla de leds informa al nadador de los tiempos y número de vueltas e, incluso, puede presentar texto (consignas) escrito por el entrenador. Este sistema se puede conectar a un PC o una PDA, permitiendo registrar los tiempos para su posterior…