67 research outputs found
Investigation of systematic errors and estimation of atom lifetime
This note describes details of analysis of data sample collected by DIRAC experiment on Ni target in 2008-2010 in order to estimate lifetime of atoms. Experimental results consists of six distinct data samples: both charge combinations ( and atoms) obtained in dierent experimental conditions corresponding to each year of data-taking. Sources of systematic errors are analyzed, and estimations of systematic errors are presented. Taking into account both statistical and systematic uncertainties, the lifetime of atoms is estimated by maximum likelihood method
Fast way to determine pp-collision time at the SPD experiment
The main task of this work is to find a fast and robust way to determine
pp-collision time t0 at the SPD experiment. Using physics motivations, from the
input flux of reconstructed particles' tracks we identify a subset of pions
which is used to calculate the unbiased estimation of the event collision time.
The uncertainty of the estimation is about 30 ps. This method is fast (less
than 300 ns per event) and reliable, thus it will allow to process the high
flux of input events at the SPD experiment.Comment: Submitted to Physics of Elementary Particles and Atomic Nuclei,
Letter
DIGITAL LONGITUDINAL FEEDBACK SYSTEMS IN SYNCHROTRONS
Abstract The stability of a beam in synchrotrons with a digital longitudinal feedback system is treated. A longitudinal feedback system is required in synchrotrons to stabilize the high intensity beams against longitudinal instabilities and to damp the phase injection errors of a bunch. Damping rates of the digital longitudinal feedback system in dependence of its gain and delay are analysed
Direct calculation of the probability of pionium ionization in the target
We performed the first direct calculation of the probability of pionium
(pi+pi- atom) ionization in the target. The dependence of the probability of
pionium ionization in the target as a function of the pionium lifetime is
established. These calculations are of interest of the DIRAC experiment at
CERN, which aims to measure the pionium lifetime with high precision.Comment: 11 pages, 4 figures; submitted to "Physics of Atomic Nuclei"
("Yadernaya Fizika"
Determination of scattering lengths from measurement of atom lifetime
The DIRAC experiment at CERN has achieved a sizeable production of
atoms and has significantly improved the precision on its lifetime
determination. From a sample of 21227 atomic pairs, a 4% measurement of the
S-wave scattering length difference
has been attained, providing an important test of Chiral Perturbation Theory.Comment: 6 pages, 6 figure
LHC Transverse Feedback System: First Results of Commissionning
A powerful transverse feedback system ("Damper") has been installed in LHC. It will stabilise the high intensity beam against coupled bunch transverse instabilities in a frequency range from 3 kHz to 20 MHz and at the same time damp injection oscillations originating from steering errors and injection kicker ripple. The LHC Damper can also be used as means of exciting transverse oscillations for the purposes of abort gap cleaning and tune measurement. The LHC Damper includes 4 feedback systems on 2 circulating beams (in other words one feedback system per beam and plane). Every feedback system consists of 4 electrostatic kickers, 4 push-pull wide band power amplifiers, 8 preamplifiers, two digital processing units and 2 beam position monitors with low-level electronics. The power and low-level subsystem layout is described along with first results from the commissioning of 16 power amplifiers and 16 electrostatic kickers located in the LHC tunnel. The achieved performance is compared with earlier predictions and requirements for injection damping and instability control. Requirements and first measurements of the performance of the power and low-level subsystems are summarized
First atom lifetime and scattering length measurements
The results of a search for hydrogen-like atoms consisting of
mesons are presented. Evidence for atom production
by 24 GeV/c protons from CERN PS interacting with a nickel target has been seen
in terms of characteristic pairs from their breakup in the same target
() and from Coulomb final state interaction (). Using
these results the analysis yields a first value for the atom lifetime
of fs and a first model-independent measurement of
the S-wave isospin-odd scattering length
( for isospin ).Comment: 14 pages, 8 figure
LHC Transverse Feedback System and its Hardware Commissioning
A powerful transverse feedback system ("Damper") has been installed in LHC. It will stabilise coupled bunch instabilities in a frequency range from 3 kHz to 20 MHz and at the same time damp injection oscillations originating from steering errors and injection kicker ripple. The transverse damper can also be used as an exciter for purposes of abort gap cleaning or tune measurement. The power and lowlevel systems layouts are described along with results from the hardware commissioning. The achieved performance is compared with earlier predictions and requirements for injection damping and instability control
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