J. Ferencei

A System for Radiation Testing and Physical Fault Injection into the FPGAs and Other Electronics

The description of equipment and methods used for conducting ionizing radiation Accelerated Life Testing (ALT) of programmable hardware, especially Field Programmable Gate Arrays (FPGA) at the cyclotron is introduced. Methodology of testing and Single Event Effects (SEE) detection and online monitoring is described together with some results of testing several SRAM and Flash based FPGAs. In the course of this work, various tool for beam monitoring and manipulating were developed.

Relative luminosity measurement of the LHC with the ATLAS forward calorimeter

In this paper it is shown that a measurement of the relative luminosity changes at the LHC may be obtained by analysing the currents drawn from the high voltage power supplies of the electromagnetic section of the forward calorimeter of the ATLAS detector. The method was verified with a reproduction of a small section of the ATLAS forward calorimeter using proton beams of known beam energies and variable intensities at the U-70 accelerator at IHEP in Protvino, Russia. The experimental setup and the data taking during a test beam run in April 2008 are described in detail. A comparison of the measured high voltage currents with reference measurements from beam intensity monitors shows a linear dependence on the beam intensity. The non-linearities are measured to be less than 0.5% combining statistical and systematic uncertainties.

A Purity Monitoring System for the H1 Liquid Argon Calorimeter

The ionization probes used for monitoring the liquid argon purity in the H1 calorimeter are described and results of their operation in tests at CERN and during the period 1992 to the end of 1998 at HERA are given. The high sensitivity of the charge measurements leads to refined charge collection models, and to the observation of a variation of the ionization yield of our electron sources with temperature.The ionization probes used for monitoring the liquid argon purity in the H1 calorimeter are described and results of their operation in tests at CERN and during the period 1992 to the end of 1998 at HERA are given. The high sensitivity of the charge measurements leads to refined charge collection models, and to the observation of a variation of the ionization yield of our electron sources with temperature.

Series tests of fine mesh photomultiplier tubes in magnetic fields of up to 1.2 Tesla

Abstract The new lead/scintillating-fibre calorimeter (“SpaCal”) for the backward region of the H1 experiment at HERA (DESY) is equipped with fine mesh phototubes which operate in a magnetic field close to 1 T. A large sample of these tubes of the types Hamamatsu R5505 and R5506, and Hamamatsu R2490-05, have been tested in fields of up to 1.2T. We have investigated the cathode homogeneity with and without magnetic field, the gain loss under the influence of the magnetic field, and stability with time. For a subsample of tubes, we have performed additional studies on stability with respect to temperature changes, variation of gain as a function of the magnetic field, high voltage discharges, single photo-electron response, and linearity. We finally summarize the experience with these tubes after one year of operation in the experiment.

Comparing proton and neutron induced SEU cross section in FPGA

Single event upsets (SEU) are induced by an electric charge deposited in the material of the chip. The origin of the charge can be either from outside of the chip or it can be generated inside as a result of a nuclear reaction. We have measured the cross section of SEUs in FPGA using protons (directly ionizing particles) and neutrons (indirectly ionizing particles). Used energies up to 34 MeV are in the range, where the differences in the protons ionizing power are most significant thanks to the Bragg peak. Measurements have shown, that the direct ionization is not the dominant effect causing SEU.

The VLQ calorimeter of H1 at HERA: a highly compact device for measurements of electrons and photons under very small scattering angles

Abstract In 1998, the detector H1 at HERA has been equipped with a small backward spectrometer, the Very Low Q 2 (VLQ) spectrometer comprising a silicon tracker, a tungsten-scintillator sandwich calorimeter, and a Time-of-Flight system. The spectrometer was designed to measure electrons scattered under very low angles, equivalent to very low squared four-momentum transfers Q 2 , and high-energy photons with good energy and spatial resolution. The VLQ was in operation during the 1999 and 2000 run periods. This paper describes the design and construction of the VLQ calorimeter, a compact device with a fourfold projective energy read-out, and its performance during test runs and in the experiment.