Optical absorption in commercial single mode optical fibres for the LHC machine

The optical absorption of light at 1310 nm and 1550 nm in various commercially available Single Mode (SM) fibres samples has been studied. The absorption was measured as a function of dose, dose rate, temperature and light power. The samples were irradiated with gamma rays from a 60Co source and exposed to a complex radiation field from high energy physics. One fibre sample with an F-doped core exhibits extreme low absorption of light at 1310 nm during irradiation up to doses of at least 100 kGy

Sub-LET Threshold SEE cross section dependency with ion energy

This study focuses on the ion species and energy dependence of the heavy ion SEE cross section in the sub-LET threshold region through a set of experimental data. In addition, a Monte Carlo based model is introduced and applied, showing a good agreement with the data in the several hundred MeV/n range while evidencing large discrepancies with the measurements in the 10-30 MeV/n interval, notably for the Ne ion. Such discrepancies are carefully analyzed and discussed

Photoproduction of eta-mesons off nuclei for Eg < 2.2 GeV

Photoproduction of $\eta$ mesons off $^{12}$C, $^{40}$Ca, $^{93}$Nb, and $^{nat}$Pb nuclei has been measured with a tagged photon beam with energies between 0.6 and 2.2 GeV. The experiment was performed at the Bonn ELSA accelerator with the combined setup of the Crystal Barrel and TAPS calorimeters. It aimed at the in-medium properties of the S$_{11}$(1535) nucleon resonance and the study of the absorption properties of nuclear matter for $\eta$ mesons. Careful consideration was given to contributions from $\eta\pi$ final states and secondary production mechanisms of $\eta$-mesons e.g. from inelastic $\pi N$ reactions of intermediate pions. The analysis of the mass number scaling shows that the nuclear absorption cross section $\sigma_{N\eta}$ for $\eta$ mesons is constant over a wide range of the $\eta$ momentum. The comparison of the excitation functions to data off the deuteron and to calculations in the framework of a BUU-model show no unexplained in-medium modifications of the S$_{11}$(1535).Comment: Accepted for publication in Eur. Phys. J.

Nucleon resonance decay by the K0Σ+K^0\Sigma^+ channel

Hyperon production off the proton in the $K^0 \Sigma^+$ channel has been studied at the tagged photon beam facility at the ELSA electron accelerator in Bonn. This experiment was part of a series of neutral meson production experiments on various targets. For this purpose, the Crystal Barrel and TAPS photon spectrometers have been combined to provide a $4 \pi$ detector for multi-neutral-particle final states. A high-quality excitation function, recoil polarizations, and angular distributions from threshold up to 2.3 GeV center-of-mass energy were obtained. The results are compared with predictions of recent coupled-channels calculations within the K-matrix formalism and are interpreted by the partial-wave analysis within the Bonn-Gatchina model.Comment: 6 pages, 5 figures, submitted to EPJ

Study of the reaction γp→pπ0η\gamma p\to p\pi^0\eta

The reaction $\gamma p\to p\pi^0\eta$ has been studied with the CBELSA detector at the tagged photon beam of the Bonn electron stretcher facility. The reaction shows contributions from $\Delta^+(1232)\eta$, $N(1535)^+\pi^0$ and $pa_0(980)$ as intermediate states. A partial wave analysis suggests that the reaction proceeds via formation of six $\Delta$ resonances, $\Delta(1600)P_{33}$, $\Delta(1920)P_{33}$, $\Delta(1700)D_{33}$, $\Delta(1940)D_{33}$, $\Delta(1905)F_{35}$, $\Delta(2360)D_{33}$, and two nucleon resonances $N(1880)P_{11}$ and $N(2200)P_{13}$, for which pole positions and decay branching ratios are given.Comment: 13 pages, 10 figures, 7 table

Study of parameters influencing the response of RADFETs

Fraunhofer INT together with CERN calibrated different RADiation-sensitive Field-Effect Transistor (RADFET) radiation dosimeters from two vendors to be operated in CERN's RadMON system with Co-60 gamma radiation to monitor total ionizing dose (TID) at CERN accelerators [1]. The aim of this study was to find out which RADFET type was best suited for the RadMON system and what parameters influence the radiation-induced threshold voltage shift of the pMOS transistors most. Therefore we looked at the sensor response while changing doserate, reading conditions, package, lot-to-lot variation during irradiation. In addition CERN previously examined the effects of different particle or radiation types on their response [2]. Compared to former measurements we reached excellent accuracies which guarantees good dose sensitivity during application at CERN. Additionally the findings of this study can also be of interest for those who will use RADFETs in space or other radiation envi ronments as dosimeters

Compromised DNA repair is responsible for diabetes-associated fibrosis.

Diabetes-associated organ fibrosis, marked by elevated cellular senescence, is a growing health concern. Intriguingly, the mechanism underlying this association remained unknown. Moreover, insulin alone can neither reverse organ fibrosis nor the associated secretory phenotype, favoring the exciting notion that thus far unknown mechanisms must be operative. Here, we show that experimental type 1 and type 2 diabetes impairs DNA repair, leading to senescence, inflammatory phenotypes, and ultimately fibrosis. Carbohydrates were found to trigger this cascade by decreasing the NAD(+)/NADH ratio and NHEJ-repair in vitro and in diabetes mouse models. Restoring DNA repair by nuclear over-expression of phosphomimetic RAGE reduces DNA damage, inflammation, and fibrosis, thereby restoring organ function. Our study provides a novel conceptual framework for understanding diabetic fibrosis on the basis of persistent DNA damage signaling and points to unprecedented approaches to restore DNA repair capacity for resolution of fibrosis in patients with diabetes

Past, present and future activities for radiation effects testing at JULIC/COSY

The testing of radiation effects (displacement damage DD, single event effects SEE) with energetic protons for electronics used in space and accelerators is of growing importance. Setup and past experience of a dedicated test stand used by Fraunhofer INT at the JULIC cyclotron will be presented. For general DD testing and for testing SEE of the trapped protons in space, the energy of 35 MeV of the JULIC Cyclotron is usually sufficient. During solar proton events, as well as at high energy accelerators (CERN, FAIR), electronics are confronted with protons of much higher energy. Recent scientific studies have shown that for single event upsets* as well as destructive failures (e.g, single event latch-ups)** a cross section measured at energies in the tens oF one/two-hundred MeV range (e.g. PIF@PSI) can significantly underestimate the failure rate. To avoid unnecessary high safety margins there is a growing need for the opportunity to test electronics at several GeV, like the beam provided by the Cooler-Synchrotron COSY in Jülich

Charge radii and moments of tin nuclei by laser spectroscopy

Copy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman