E. Tuovinen

Radiation hardness of Czochralski silicon studied by 10-MeV and 20-MeV protons

We have processed pin-diodes on Czochralski silicon (Cz-Si), standard float zone silicon (Fz-Si), and diffusion oxygenated float zone silicon (DOF) and irradiated them with 10- and 20-MeV protons. Evolutions of depletion voltage and leakage current as a function of irradiation dose were measured. Space charge sign inversion (SCSI) was investigated by an annealing study and verified by transient current technique (TCT). Czochralski silicon was found to be significantly more radiation hard than the other materials.

Test beam results of a large area strip detector made on high resistivity Czochralski silicon

Abstract We have tested the detection performance of a strip detector processed on silicon wafer grown by magnetic Czochralski (MCZ) method. This is the first time a full size Czochralski detector has been tested in a beam, although the advantages of CZ silicon have been known before. Prior to test beam measurements, the electrical characteristics of the Czochralski silicon detectors were found to be appropriate for particle detection. Using the Helsinki Silicon Beam telescope at CERN H2 test beam, the performance of the Czochralski silicon detector was shown to be comparable with the existing silicon strip detectors.

Recent Progress in CERN RD39: Radiation Hard Cryogenic Silicon Detectors for Applications in LHC Experiments and Their Future Upgrades

CERN RD39 Collaboration develops radiation-hard cryogenic silicon detectors. Recently, we have demonstrated improved radiation hardness in novel Current Injected Detectors (CID). For detector characterization, we have applied cryogenic Transient Current Technique (C-TCT). In beam tests, heavily irradiated CID detector showed capability for particle detection. Our results show that the CID detectors are operational at the temperature -50°C after 1016 1 MeV neutron equivalent fluence.

Strip Detectors Processed on High-Resistivity 6-inch Diameter Magnetic Czochralski Silicon (MCz-Si) Substrates

Tracking detectors for future high-luminosity particle physics experiments have to be simultaneously radiation hard and cost efficient. This paper describes processing and characterization of p+ /n-/n+ (n-type silicon bulk) detectors made of high-resistivity Magnetic Czochralski silicon (MCz-Si) substrates with 6-inch wafer diameter. The processing was carried out on a line used for large-scale production of sensors using standard fabrication methods, such as implanting polysilicon resistors to bias individual sensor strips. Special care was taken to avoid the creation of Thermal Donors (TD) during processing. The sensors have a full depletion voltage of 120-150 V which are uniform over the investigated sensors. All of the leakage current densities were below 55 nA/cm2 at 200 V bias voltage. A strip sensor with 768 channels was attached to readout electronics and tested in particle beam with a data acquisition (DAQ) similar to the system used by the CMS experiment at the CERN LHC. The test beam results show a signal-to-noise ratio greater than 40 for the test beam sensor. The results demonstrate that MCz-Si detectors can reliably be manufactured in the industrial scale semiconductor process.

Search for anomalous couplings in boosted WW/WZ -> l nu q(q)over-bar production in proton-proton collisions at root s=8TeV

This Letter presents a search for new physics manifested as anomalous triple gauge boson couplings in WW and WZ diboson production in proton-proton collisions. The search is performed using events containing a W boson that decays leptonically and a W or Z boson whose decay products are merged into a single reconstructed jet. The data, collected at √ s = 8 TeV with the CMS detector at the LHC, correspond to an integrated luminosity of 19 fb−1. No evidence for anomalous triple gauge couplings is found and the following 95% confidence level limits are set on their values: λ ([−0.011, 0.011]), ∆κγ ([−0.044, 0.063]), and ∆gZ 1 ([−0.0087, 0.024]). These limits are also translated into their effective field theory equivalents: cWWW/Λ ([−2.7, 2.7]TeV−2), cB/Λ ([−14, 17]TeV−2), and cW/Λ ([−2.0, 5.7]TeV−2). Published in Physics Letters B as doi:10.1016/j.physletb.2017.06.009. c

Forward-backward asymmetry of Drell-Yan lepton pairs in pp collisions at root s=8 TeV

A measurement of the forward–backward asymmetry

Silicon beam telescope for LHC upgrade tests

{A}_{\mathrm{FB}}

Setup for irradiation and characterization of materials and si particle detectors at cryogenic temperatures

AFB of oppositely charged lepton pairs (