78 research outputs found
Development of a multi-channel power supply for silicon photo-multipliers used with inorganic scintillators
The motivation of the current R&D project is based upon the requirements of
the JEDI international collaboration aiming to measure Electric Dipole Moments
(EDMs) of charged particles in storage rings. One of the most important
elements of such an experiment will be a specially designed polarimeter with
the detection system based on a modular inorganic scintillator (LYSO crystal)
calorimeter. The calorimeter modules are read out by Silicon Photo Multipliers
(SiPMs). This paper describes the development of a multi-channel power supply
for the polarimeter modules, providing very stable and clean bias voltages for
SiPMs. In order to ensure the best possible performance of SiPMs in conjunction
with the crystal-based calorimeter modules and to guarantee the required level
of calorimeter stability, several quality requirements have to be met by the
power supply. Additionally, it is required to provide features including remote
control via the network, ramping of the output voltage, measuring and sending
the information about its output voltages and currents, etc. The obtained
results demonstrate that the goals for the JEDI polarimeter are met. The
developed hardware will be useful in other fields of fundamental and applied
research, medical diagnostic techniques and industry, where SiPMs are used
Collective oscillations of a stored deuteron beam close to the quantum limit
We investigated coherent betatron oscillations of a deuteron beam in the
storage ring COSY, excited by a detuned radio-frequency Wien filter. These beam
oscillations were detected by conventional beam position monitors, read out
with lock-in amplifiers. The response of the stored beam to the detuned Wien
filter was modelled using the ring lattice and time-dependent 3D field maps of
the radio-frequency Wien filter. The influence of uncertain system parameters
related to manufacturing tolerances and electronics was investigated using the
polynomial chaos expansion. With the currently available apparatus, we show
that oscillation amplitudes down to \SI{1}{\micro \meter} can be detected.
Future measurements of the electric dipole moment of protons will, however,
require control of the relative position of counter-propagating beams in the
sub-picometer range. Since the stored beam can be considered as a rarefied gas
of uncorrelated particles, we moreover demonstrate that the amplitudes of the
zero-point betatron oscillations of individual particles are within a factor of
10 of the Heisenberg uncertainty limit. As a consequence of this, we conclude
that quantum mechanics does not preclude the control of the beam centroids to
sub-picometer accuracy. The smallest Lorentz force exerted on a single particle
that we have been able to determine is \SI{10}{aN}.Comment: 38 pages, 16 figure
Der Wissenschaftlich-Technische Rat - Wer ist das, was macht er, und warum eigentlich?
Festschrift zum fünfzigjährigen Bestehen der Hauptkommission des Wissenschaftlich-Technischen Rate
N*ews from COSY
COSY, a storage and cooler synchrotron, which is fed by an injector cyclotron, is operated at Forschungszentrum Juelich (Germany). It provides phase space cooled polarized or unpolarized beams of protons and deuterons with momenta between 0.3 and 3.7 GeV/c for internal experiments and to external target stations. The major experimental facilities, used for the ongoing physics program, are ANKE and WASA (internal) and TOF (external). A new internal target station to investigate polarization build-up by spin-filtering (PAX) has recently been commissioned. COSY is the machine for hadron spin physics on a world-wide scale, which in recent times is also used for tests in conjunction with plans to build a dedicated storage ring for electric dipole moment (EDM) measurements of proton, deuteron and 3He. In this contribution selected experimental results from the N*-program are presented
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