Application of introduced nano-diamonds for the study of carbon condensation during detonation of high explosives

This paper describes the experimental studies of the formation of nano-diamonds during detonation of TNT/RDX 50/50 mixture with small-angle x-ray scattering (SAXS) method at a synchrotron radiation beam on VEPP-3 accelerator. A new experimental method with introduction of nano-diamonds into the explosive has been applied. Inclusion of the diamonds obtained after detonation into the TNT and RDX explosives allows modelling of the case of instant creation of nano-diamonds during detonation.Comment: Latex, 4 pages, 2 figures (proc. of SR-2008

Optimization of design and beam test of microstrip gas chambers

We describe recent experimental and theoretical work aimed at optimizing the geometry and the operation of micro-strip gas chambers in order to improve their performance and reliability. With the help of a simulation program, we have studied the mechanism of signal propagation and analyzed the effects on signal shape and size of resistivity of strips, grouping of biased strips and presence of a back-plane. Several detectors manufactured according to the results of the study and equipped with fast amplifiers have been installed in a test beam to study general operating characteristics, efficiency and localization accuracy; preliminary results of the data analysis are discussed

Study of the spatial resolution of low-material GEM tracking detectors

The spatial resolution of GEM based tracking detectors has been simulated and measured. The simulation includes the GEANT4 based transport of high energy electrons with careful accounting for atomic relaxation processes including emission of fluorescent photons and Auger electrons and custom post-processing, including accounting for diffusion, gas amplification fluctuations, the distribution of signals on readout electrodes, electronics noise and a particular algorithm of the final coordinate calculation (center of gravity). The simulation demonstrates that a minimum of the spatial resolution of about 10 μm can be achieved with strip pitches from 250 μm to 300 μm. For larger pitches the resolution is quickly degrading reaching 80-100 μm at a pitch of 500 μm. The spatial resolution of low-material triple-GEM detectors for the DEUTRON facility at the VEPP-3 storage ring is measured at the extracted beam facility of the VEPP-4M collider. The amount of material in these detectors is reduced by etching the copper of the GEMs electrodes and using a readout structure on a thin kapton foil rather than on a glass fibre plate. The exact amount of material in one DEUTRON detector is measured by studying multiple scattering of 100 MeV electrons in it. The result of these measurements is X/X0 = 2.4×10−3 corresponding to a thickness of the copper layers of the GEM foils of 3 μm. The spatial resolution of one DEUTRON detector is measured with 500 MeV electrons and the measured value is equal to 35 ± 1 μm for orthogonal tracks

Study of the spatial resolution of low-material GEM tracking detectors

The spatial resolution of GEM based tracking detectors has been simulated and measured. The simulation includes the GEANT4 based transport of high energy electrons with careful accounting for atomic relaxation processes including emission of fluorescent photons and Auger electrons and custom post-processing, including accounting for diffusion, gas amplification fluctuations, the distribution of signals on readout electrodes, electronics noise and a particular algorithm of the final coordinate calculation (center of gravity). The simulation demonstrates that a minimum of the spatial resolution of about 10 μm can be achieved with strip pitches from 250 μm to 300 μm. For larger pitches the resolution is quickly degrading reaching 80-100 μm at a pitch of 500 μm. The spatial resolution of low-material triple-GEM detectors for the DEUTRON facility at the VEPP-3 storage ring is measured at the extracted beam facility of the VEPP-4M collider. The amount of material in these detectors is reduced by etching the copper of the GEMs electrodes and using a readout structure on a thin kapton foil rather than on a glass fibre plate. The exact amount of material in one DEUTRON detector is measured by studying multiple scattering of 100 MeV electrons in it. The result of these measurements is X/X0 = 2.4×10−3 corresponding to a thickness of the copper layers of the GEM foils of 3 μm. The spatial resolution of one DEUTRON detector is measured with 500 MeV electrons and the measured value is equal to 35 ± 1 μm for orthogonal tracks

Simulation of different options of the Inner Tracker for Novosibirsk Super Charm-Tau Factory Detector

Inner Tracker of Novosibirsk Super Charm-Tau Factory Detector has to measure momenta of soft hadrons, which do not reach the drift chamber; complement the drift chamber in measuring the momenta; detect secondary vertices of short-lived particles. Thus, proper choice of the option for the Inner Tracker is of significant interest. The simulation of charged pions propagation in the perpendicular direction to the beam axis was carried out with DD4HEP program based on GEANT4. Three options were considered: 4-layered Silicon microstrip detector, 4-layered cylindrical Gas Electron Multiplier (GEM) detector and Time Projection Chamber (TPC). The simulated Detector was located in 1.5 T magnetic field directed along beam axis. The simulation shows that pions with initial momenta less than 50 MeV/c do not pass through the beampipe and cannot be registered. Pions with momenta above 65 MeV/c leave energy depositions in all 4 layers of the Inner Tracker based on Silicon, and their trajectories can be reconstructed. Cylindrical GEM detector provides reconstruction possibility (hits in 4 layers) for pions with momenta more than 60 MeV/c. TPC with thin inner wall provides reconstruction of pions with momenta higher than 55 MeV/c. However, in this case the reconstruction procedure will be much more complicated due to a large number of background particle tracks in the sensitive volume

Simulation of different options of the Inner Tracker for Novosibirsk Super Charm-Tau Factory Detector

Inner Tracker of Novosibirsk Super Charm-Tau Factory Detector has to measure momenta of soft hadrons, which do not reach the drift chamber; complement the drift chamber in measuring the momenta; detect secondary vertices of short-lived particles. Thus, proper choice of the option for the Inner Tracker is of significant interest. The simulation of charged pions propagation in the perpendicular direction to the beam axis was carried out with DD4HEP program based on GEANT4. Three options were considered: 4-layered Silicon microstrip detector, 4-layered cylindrical Gas Electron Multiplier (GEM) detector and Time Projection Chamber (TPC). The simulated Detector was located in 1.5 T magnetic field directed along beam axis. The simulation shows that pions with initial momenta less than 50 MeV/c do not pass through the beampipe and cannot be registered. Pions with momenta above 65 MeV/c leave energy depositions in all 4 layers of the Inner Tracker based on Silicon, and their trajectories can be reconstructed. Cylindrical GEM detector provides reconstruction possibility (hits in 4 layers) for pions with momenta more than 60 MeV/c. TPC with thin inner wall provides reconstruction of pions with momenta higher than 55 MeV/c. However, in this case the reconstruction procedure will be much more complicated due to a large number of background particle tracks in the sensitive volume