•V389 Cas is detached eclipsing binary on circular orbit.•Delta Scuti pulsations were found on secondary component.•These pulsations have the period of about 0.037day.
New CCD observations of V389 ...Cas were carried out in the observatories in the Czech Republic from 2010 to 2014. These new data were analysed using the program PHOEBE. V389 Cas was found to be a detached eclipsing binary system with two rather different components moving on a circular orbit. Moreover, there was discovered also a δ-Scuti-type behaviour of the secondary component. These pulsations have the period of about 0.037day. This result is being compared with the previous findings on similar eclipsing-pulsation systems published by Zhang et al. (2013).
The work concerns the development of aerogel radiators for RICH detectors. Aerogel tiles with a refractive index of 1.05 were tested with a RICH prototype on the electron beam on the VEPP-4M ...collider. It has been shown that polishing with silk tissue yields good surface quality, the amount of light loss at this surface being about 5–7%. The Cherenkov angle resolution was measured for a tile in two conditions: with a clean exit face and with a polished exit face. The number of photons detected was 13.3 and 12.7 for the clean and polished surfaces, respectively. The Cherenkov angle resolution for the polished surface is 55% worse, which can be explained with the forward scattering on the polished surface. A tile with a crack inside was also tested. The experimental data show that the Cherenkov angle resolution is the same for tracks crossing the crack area and in a crack-free area.
Tests of FARICH prototype with precise photon position detection Barnyakov, A.Yu; Barnyakov, M.Yu; Basok, I.Yu ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2014, Letnik:
766
Journal Article
Recenzirano
In June 2012 a FARICH prototype from Philips Digital Photon Counting (PDPC) based on a photon camera with dimensions of 200200 mm has been tested at CERN. Remarkable particle separation has been ...achieved with a 4-layer aerogel sample: the pi /K separation at a 6 GeV/c momentum is 3.5 sigma , the mu / pi mu / pi separation is 5.3 sigma at 1 GeV/c. The analysis of the data has shown that the main contribution to the accuracy of the ring radius measurement comes from aerogel. The development of focusing aerogels is proceeding in two main directions: tuning of production technology of multilayer blocks and development of a new production method with continuous density (refractive index) gradient along the block depth. The beam test was carried out in December 2012-January 2013 at the electron beam test facility at the VEPP-4 M e super(+)e super(-) collider. The goal of this test was to measure different single layer and focusing aerogel samples, both multilayer and gradient. Aerogel samples were tested with a PDPC FARICH prototype. A part of DPC SPADs in each pixel was disabled to form an active area of 11 mm super(2). The collected data proved that gradient aerogel samples focus Cherenkov light.
The Super C-
τ
(SCT) Factory at Novosibirsk is a project of new colliding beam experiment proposed in Budker Institute of Nuclear Physics. Electron-positron collider based on Crab-Waist technique for ...operation energy range 2–5 GeV in center of mass is suggested. The luminosity up to 10
35
cm
−1
s
−1
(in 100 times higher than in operated today experiments in this energy region) is expected. To perform broad experimental program of the project successfully the excellent particle identification (PID) system is needed. A number of options are under consideration. Three of them are described in the paper: Focusing Aerogel RICH (FARICH) detector, threshold Cherenkov counters based on ASHIPH (Aerogel SHifter PHotomultiplier) technique with 6000 litres of aerogel of two refractive indexes and time-of-flight counters with TOP (Time of Propagation) approach with time resolution better than 30 ps. Comparison of PID capabilities with help of parametric simulation is given.
Downflows on the solar surface are suspected to play a major role in the dynamics of the convection zone. We investigate the existence of the long-lasting downflows whose effects influence the ...interior of the Sun and the outer layers. We study the sets of Dopplergrams and magnetograms observed with SDO and Hinode spacecrafts and a MHD simulation. All of the aligned sequences, which were corrected from the satellite motions and tracked with the differential rotation, were used to detect the long-lasting downflows in the quiet-Sun at the disc centre. To learn about the structure of the flows below the solar surface, the time-distance local helioseismology was used. The inspection of the 3D data cube (x, y, t) of the 24-hour Doppler sequence allowed us to detect 13 persistent downflows. Their lifetimes lie in the range between 3.5 and 20 hours with sizes between 2" and 3" and speeds between -0.25 and -0.72 km/s. These persistent downflows are always filled with the magnetic field with an amplitude of up to 600 G. The helioseismic inversion allows us to describe the persistent downflows and compare them to the other (non-persistent) downflows in the field of view. The persistent downflows seem to penetrate much deeper and, in the case of a well-formed vortex, the vorticity keeps its integrity to the depth of about 5 Mm. In the MHD simulation, only sub-arcsecond downflows are detected with no evidence of a vortex comparable in size to observations at the surface of the Sun. The long temporal sequences from the space-borne allow us to show the existence of long-persistent downflows together with the magnetic field. They penetrate inside the Sun but are also connected with the anchoring of coronal loops in the photosphere, indicating a link between downflows and the coronal activity. A link suggests that EUV cyclones over the quiet Sun could be an effective way to heat the corona.
Aims. To investigate the role of acoustic and magneto-acoustic waves in heating the solar chromosphere, observations in strong chromospheric lines are analyzed by comparing the deposited ...acoustic-energy flux with the total integrated radiative losses. Methods. Quiet-Sun and weak-plage regions were observed in the Ca II 854.2 nm and H-alpha lines with the Fast Imaging Solar Spectrograph (FISS) at the 1.6-m Goode Solar Telescope (GST) on 2019 October 3 and in the H-alpha and H-beta lines with the echelle spectrograph attached to the Vacuum Tower Telescope (VTT) on 2018 December 11 and 2019 June 6. The deposited acoustic energy flux at frequencies up to 20 mHz was derived from Doppler velocities observed in line centers and wings. Radiative losses were computed by means of a set of scaled non-LTE 1D hydrostatic semi-empirical models obtained by fitting synthetic to observed line profiles. Results. In the middle chromosphere (h = 1000-1400 km), the radiative losses can be fully balanced by the deposited acoustic energy flux in a quiet-Sun region. In the upper chromosphere (h > 1400 km), the deposited acoustic flux is small compared to the radiative losses in quiet as well as in plage regions. The crucial parameter determining the amount of deposited acoustic flux is the gas density at a given height. Conclusions. The acoustic energy flux is efficiently deposited in the middle chromosphere, where the density of gas is sufficiently high. About 90% of the available acoustic energy flux in the quiet-Sun region is deposited in these layers, and thus it is a major contributor to the radiative losses of the middle chromosphere. In the upper chromosphere, the deposited acoustic flux is too low, so that other heating mechanisms have to act to balance the radiative cooling.
PDF
