Search results for " Ring"

Radioactive beams at GSI

2001

Abstract After a brief introduction the production of relativistic beams of exotic nuclei will be discussed and some characteristic examples from the ongoing GSI nuclear structure research programme are presented, such as: nuclear reactions with exotic beams to explore nuclear skins, the structure of halo nuclei, and direct mass measurements in a storage ring. Heavy-element research will be addressed briefly. A possible next generation exotic beam facility at GSI will be outlined.

Measurements of relativistic time dilatation for positive and negative muons in a circular orbit

1977

The lifetimes of both positive and negative relativistic (γ = 29.33) muons have been measured in the CERN Muon Storage Ring with the results τ+ = 64.419 (58) µs, τ− = 64.368 (29) µs The value for positive muons is in accordance with special relativity and the measured lifetime at rest: the Einstein time dilation factor agrees with experiment with a fractional error of 2×10−3 at 95% confidence. Assuming special relativity, the mean proper lifetime for μ− is found to be τ0− = 2.1948(10) µs the most accurate value reported to date. The agreement of this value with previously measured values of τ0+ confirms CPT invariance for the weak interaction in muon decay.

First Antiprotons in an Ion Trap

1987

Measurements of the antiproton mass[2,3,4,5] are represented in Fig. 1. All of these are deduced from measurements of the energy of x-rays radiated from highly excited exotic atoms. For example, if an antiproton is captured in a Pb atom, it can make radiative transitions from its n = 20 to n = 19 state. The antiproton is still well outside the nucleus in this case, so that nuclear effects can be neglected. The measured transition energy is essentially proportional to the reduced mass of the nucleus and hence the antiproton mass can be deduced by comparing the measured values with theoretical values, corrected for QED effects. The most accurate quoted uncertainty is 5 × 10-5 and is consisten…

Emittance Growth by Synchrotron Radiation in a Double-Sided Microtron

1999

Here we present results of calculations of emittance growth caused by quantum fluctuations of synchrotron radiation (QFSR) for a 1.5 GeV double-sided microtron (DSM). We did both semi-analytical estimations, employing known Twiss parameters for the DSM orbits, and a computer simulation of these stochastic effects using the program SYTRACE. This showed that the normalized emittance growth was within reasonable limits, by a factor of about 1.5, thus permitting e.g. the installation of small aperture linacs on the DSM axes.

Test of Special Relativity in a Heavy Ion Storage Ring

2008

Nuclear structure physics at GSI-challenges and perspectives

2001

Some characteristic examples from the ongoing GSI nuclear structure research programme are presented such as recent experimental results from nuclear reactions with exotic beams to explore the structure of halo nuclei, direct mass measurements in the storage ring, and the structure of heavy-elements. A brief outline of a next generation exotic beam facility will be given.

The Pion Single-Event Effect Resonance and its Impact in an Accelerator Environment

2020

International audience; The pion resonance in the nuclear reaction cross section is seen to have a direct impact on the single-event effect (SEE) cross section of modern electronic devices. This was experimentally observed for single-event upsets and single-event latchup. Rectangular parallelepiped (RPP) models built to fit proton data confirm the existence of the pion SEE cross-section resonance. The impact on current radiation hardness assurance (RHA) soft error rate (SER) predictions is, however, minimal for the accelerator environment since this is dominated by high neutron fluxes. The resonance is not seen to have a major impact on the high-energy hadron equivalence approximation estab…

Two-step nilpotent Leibniz algebras

2022

In this paper we give a complete classification of two-step nilpotent Leibniz algebras in terms of Kronecker modules associated with pairs of bilinear forms. In particular, we describe the complex and the real case of the indecomposable Heisenberg Leibniz algebras as a generalization of the classical $(2n+1)-$dimensional Heisenberg Lie algebra $\mathfrak{h}_{2n+1}$. Then we use the Leibniz algebras - Lie local racks correspondence proposed by S. Covez to show that nilpotent real Leibniz algebras have always a global integration. As an application, we integrate the indecomposable nilpotent real Leibniz algebras with one-dimensional commutator ideal. We also show that every Lie quandle integr…

BEM-Based Magnetic Field Reconstruction by Ensemble Kálmán Filtering

2022

Abstract Magnetic fields generated by normal or superconducting electromagnets are used to guide and focus particle beams in storage rings, synchrotron light sources, mass spectrometers, and beamlines for radiotherapy. The accurate determination of the magnetic field by measurement is critical for the prediction of the particle beam trajectory and hence the design of the accelerator complex. In this context, state-of-the-art numerical field computation makes use of boundary-element methods (BEM) to express the magnetic field. This enables the accurate computation of higher-order partial derivatives and local expansions of magnetic potentials used in efficient numerical codes for particle tr…

Matrix metalloproteinase-1 is differentially expressed in signet ring cell, and intestinal colorectal carcinomas histotypes

2007

14564 Background: Signet ring cell colorectal carcinoma ( SRCC) pure is an infrequent and highly malignant variant of colorectal cancer, while this histological component is present in 30% of all colorectal carcinomas. In our previous studies we compared the E- Cadherin, β- Catenin, Fibronectin, Ki 67 and Thymidylate Synthase (TS) expression of SRCC, the intestinal type of colorectal carcinoma (ICRC) to try to explain the pathogenesis, the aggressiveness and the low 5 Fluorouracil (5FU) responsiveness of these tumours. We found that all SRCCs had very low levels of all markers and were in the post- mitotic phase of the cell cycle. To understand their high metastatic capability we assessed …