119238918
A beam monitor detector based on doped silica and optical fibres
A beam monitor detector prototype based on doped silica fibres coupled to optical fibres has been designed, constructed and tested, mainly for accelerators used in medical applications. Scintillation light produced by Ce and Sb doped silica fibres moving across the beam has been measured, giving information on beam position, shape and intensity. Mostly based on commercial components, the detector is easy to install, to operate and no electronic components are located near the beam. Tests have been performed with a 2 MeV proton pulsed beam at an average current of 0.8 μA. The response characteristics of Sb doped silica fibres have been studied for the first time.
124388402
Strangelet search and particle production studies in Pb + Pb collisions at 158-A-GeV/c at CERN SPS
We searched for long-lived strange quark matter particles, so-calledstrangelets, and studied particle and antiparticle production in Pb+Pb collisions at 158 GeV/c per nucleon at zero degree production angle. We give upper limits for the production of strangelets covering a mass to charge ratio up to 120 GeV/c 2 and lifetimest lab>1.2 μs and plot invariant differential production cross sections as a function of rapidity for a variety of particles.
122225376
An investigation of the antinuclei and nuclei production mechanism in Pb + Pb collisions at 158 A GeV
We investigate the production mechanisms of p, d, t, 3He, 4He, 6Li, , and in Pb+Pb collisions at 158 A GeV measured near zero transverse momentum with the NA52 experiment at the CERN SPS. We find evidence that nuclei and antinuclei in Pb+Pb collisions are mainly produced via the coalescence mechanism out of a thermalized source of hadrons, at a time close to the thermal freeze-out of hadrons corresponding to a temperature of ~120 MeV.
123035541
The NA52 strangelet search
The NA52 experiment searches for long-lived charged strangelets in 158 A GeV c-1 Pb + Pb collisions at CERN SPS. The experiment is able to identify single particles coming from the collisions at pt = 0. We collected 1013 Pb + Pb interactions looking for negatively charged strangelets and 3 × 1011 Pb + Pb interactions for positively charged ones. No evidence for the production of strangelets has been observed. We present here resulting experimental differential and total upper production limits.
17991299
Strangelets, strangeness and antimatter: results from the experiment NA52 at CERN
We present results of the CERN experiment NA52 which measures Pb+Pb collisions at 158 A GeV. The topics we address are: 1. strangelet search, 2. nuclei and antinuclei production and 3. strangeness production. No strangelets have been found. We set upper limits which stretch down to the minimal values of ∼ 2 10−10 for negatively and 3 10−9 for positively charged strangelets. We observed 5 3He near midrapidity. Nuclei and antinuclei cross sections suggest production mainly through coalescence, out of a thermalised particle source, at the time of the thermal freeze-out as witnessed by their temperature of 100-120 MeV. Charged kaons per participant nucleon (Np) show an onset of enhancement followed by saturation at Np ∼ 80, corresponding approximately to an initial energy density of i ∼ 1.3 GeV/fm. This onset may be connected to the onset of the QCD phase transition.
117392007
Recent results from experiment NA52 at the CERN SPS
We present recent results of the NA52 experiment on the strangelet search and on particle, antiparticle, light nuclei and antinuclei production in minimum bias Pb + Pb collisions at 158 A GeV and zero production angle. Upper limits for the production of strangelets are given and one candidate found using less stringent lifetime cuts is discussed. The rapidity dependence of K+(K−), p(), d(), t and as well as first results on 4He, 6Li and 7Be at forward rapidities are presented. First results on the centrality dependence of the /p ratio are reported. Within the framework of a thermodynamical and a coalescence model, the temperature, the baryon- and strangeness-chemical potentials and the radius of the particle source at midrapidity have been estimated.
109952852
Power supply and pulsing strategies for the future linear colliders
The concept of the power delivery systems of the future linear colliders exploits the pulsed bunch structure of the beam in order to minimize the average current in the cables and the electronics and thus to reduce the material budget and heat dissipation. Although modern integrated circuit technologies are already available to design a low-power system, the concepts on how to pulse the front-end electronics and further reduce the power are not yet well understood. We propose a possible implementation of a power pulsing system based on a DC/DC converter and we choose the Analog Hadron Calorimeter as a specific example. The model features large switching currents of electronic modules in short time intervals to stimulate the inductive components along the cables and interconnections.
110237207
Evaluation of MCM-D technology for silicon strip detectors
Abstract Multi-chip Modules-Deposited (MCM-D) is a technology that can be applied to silicon strip modules and promises advantages in terms of integration complexity and material budget. This technology permits to integrate the front-end hybrid, pitch adaptor and wire bonds on the silicon sensor. The principle is to deposit alternating dielectric and metal layers directly on the silicon, where traces and vias are etched with high resolution to produce a PCB like structure. This paper reports on a prototype MCM-D processing run of silicon strip wafers performed to evaluate suitability of the technology. This first run uses one dielectric layer, one metal layer, passivation and a final metallisation appropriate for wire-bonding. Connections are done through the first dielectric layer to the strips, the bias ring, bias resistors and guard rings. Hence the effects of the post-processing on the silicon sensor are evaluated measuring change in parameters such as I / V and C / V characteristics, inter-strip capacitance and resistance.
110779087
The SVX4 integrated circuit
Abstract A first prototype of the SVX4 readout IC with enclosed transistor layout for radiation tolerance has been fabricated in a commercial 0.25 μm bulk CMOS process. The SVX4 is intended to instrument the CDF and D0 Run IIB silicon strip detector upgrades at Fermilab. The design and test results are discussed.
55821746
Trilepton final state from neutralino-chargino production in mSUGRA.
The direct production of neutralino-chargino pairs in the mSUGRA scenario with decays into pure trilepton final states has a significant cross section for low neutralino masses. The trilepton signature was studied with the full and fast CMS detector simulations. The 5 signal can be observed in the dilepton invariant mass distribution at the integrated luminosity of L 30 fb for GeV.
8016343
Testing coupling relations in SUSY QCD at a linear collider
Supersymmetry predicts that gauge couplings are equal to the corresponding gaugino-sfermion-fermion Yukawa couplings. This prediction can be tested for the QCD sector of the MSSM by studying the processes eplus+eminus -> squark+antisquark+gluon and eplus+eminus -> squark+antiquark+gluino at a future linear collider. We present results for these processes at next-to-leading order in alpha_s in the framework of the MSSM. We find sizable SUSY-QCD corrections. The renormalization scale dependence is significantly reduced at next-to-leading order.