114023912
Performance of a wide pitch n-on-n silicon detector with floating strips
1648236
The LHCb VELO: status and upgrade developments
The VErtex LOcator (VELO) is the silicon microstrip vertexing and triggering sub-detector of the LHCb experiment. It consists of a series of forward disks with the active region extending to just 8 mm from the LHC beams. The current status of the VELO is presented. Due to the high radiation environment, the VELO may have to be replaced after some years, possibly with new materials. A candidate material is Czochralski silicon. We present here promising new results on the first test beam of a large, high resistivity Czochralski microstrip silicon detector read out with LHC speed electronics. The performance was studied before and after irradiation with high energy protons. A signal to noise of over 20:1 was obtained from the detector and significant charge collection efficiencies were measured at relatively modest voltages after a fluence of 4.3/spl times/10/sup 14/ 1 MeV neutron equivalents (n/sub eq/) per cm/sup 2/. Studies using the Transient Current Technique probed the electric field within MCz test detectors and proved that MCz silicon does not type invert up until a radiation level of at least 5/spl times/10/sup 14/ 24GeV/c p/cm/sup 2/. This would mean the VELO could possibly replace, in a potential upgrade, n/sup +/-on-n DOFZ sensors and the complicated processing involved, for standard p/sup +/-on-n processing with MCz.
122010968
LUMINOSITY MONITORING AT LHCb
208345688
VELO Geometry Optimisation
New possible layouts of the LHCb Vertex Locator (VELO) have been compared with the existing baseline design outlined in the Technical Proposal. Based on a comparison of essential figures of merit, namely vertex resolutions, event selection efficiencies, trigger performance, and technical constraints an updated baseline design is proposed. The new design retains the same number of electronic channels as that in the Technical Proposal, but has an increased number of measuring stations (25 rather than 17) with a reduced inner radius (8mm rather than 10mm).
15273175
The LHCb trigger strategy and performance
Precise measurements of CP-violating asymmetries, oscillation parameters and branching ratios on numerous B-decay channels will allow an overdetermination of CKM parameters, with possible inconsistencies pointing to physics beyond the Standard Model. In order to achieve this, an experiment capable of triggering on the various decay modes of B-mesons (in particular hadronic modes) is desirable. LHCb [ 1] is an experiment dedicated to such precision studies at the large hadron collider (LHC). It is designed as a forward spectrometer, because BB pairs are expected to be predominantly produced at small polar angles. An overview of the LHCb detector and trigger scheme is shown in Figure 1.
121605096
Performance of an irradiated LHCb prototype p-on-n silicon microstrip detector
Abstract A prototype silicon detector for the LHCb experiment has been irradiated non-uniformly with fluences of up to 10 15 p / cm 2 of 24 GeV protons and tested with LHC speed electronics in a test beam. After doses equivalent to one year of operation at the LHC, the detector was operational, and deteriorated after higher doses. The performance of this detector identifies particular risks associated with a p-on-n fine pitch design with a double metal layer.
120396510
Scintillation fiber hodoscope for topological triggering
A fast and precise scintillating fiber (SciFi) hodoscope based on KURARAY SciFi and HAMAMATSU multianode H6568 tubes was constructed to be used in DIRAC experiment (PS-212) at CERN for tracking and topological triggering information. The front-end electronics was custom developed to allow on-line discrimination after built-in dynamic cross-talk rejection. Preliminary tests of the detector using more than 300 read-out channels have shown an excellent stability and optimum performance for this system: a uniform detection efficiency of 98%, a 125 μm single hit and ∼0.5 mm two-hit space resolution, 0.6 ns time resolution.
124427418
A large-acceptance detector system for electron scattering from polarized internal targets
Abstract The design and the performance of a non-magnetic detector setup for internal target physics at the NIKHEF electron-scattering facility is described. The detector setup, used in the first internal-target experiment at the AmPS ring, measures the spin dependence in the elastic and break-up reaction channels from tensor polarized deuterium. It has been established that the detector setup can operate adequately in an internal target environment at luminosities up to 10 32 e − atoms cm −2 s −1 . Results and measured resolutions are presented.
120844255
Ion-Extraction Polarimetry for Polarized Internal Targets.
Abstract We discuss ion extraction from an internal target in a storage ring, separation of atomic and molecular species, and subsequent measurement of the polarization of the atomic ions. This technique can be applied to internal targets of polarized hydrogen, deuterium, 3 He and other gases. Here, we report on the development of such a device for a tensor polarized deuterium gas target internal to a medium-energy electron storage ring. Ions were extracted from a storage cell using a spherical deflector and transported to a mass analyzer. In a prototype setup, using electrons from a gun to simulate the electron beam from a storage ring, the tensor polarization of the atomic ions was measured using the 3 H(d, n) α reaction. The data show that the extraction of ions from a storage-cell target, followed by their mass and polarization analysis, allows the determination of the nuclear polarization of the target independent of its spatial and temporal variations.
121045221
Ultraviolet Cherenkov light detector
Abstract An increase by a factor ∼3.4 in photoelectron emission from Cherenkov light has been observed after coating a standard photomultiplier of the XP1040 class (Philips) with a thin deposit of scintillating material (wavelength shifter). The coating operation is straightforward and requires simple manipulations. We have used coated phototubes in a conventional gas Cherenkov counter exposed to an electron beam at the CERN PS. We measure a figure of merit for the system of N 0 ∼ 170 photoelectrons per cm.
122279335
The real part of the forward scattering amplitude in π±p elastic scattering below 2 GeV/c
Abstract The differential cross section for π ± p elastic scattering below 2 GeV/ c has been measured at small forward pion angles by an electronics experiment. The interference effects observed between the Coulomb and the nuclear interaction have been used to determine the magnitude and sign of the real parts of the π ± p forward scattering amplitude. The latter are compared to the values predicted by the dispersion relations.