Investigation of HV/HR-CMOS technology for the ATLAS Phase-II Strip Tracker Upgrade

ATLAS has formed strip CMOS project to study the use of CMOS MAPS devices as silicon strip sensors for the Phase-II Strip Tracker Upgrade. This choice of sensors promises several advantages over the conventional baseline design, such as better resolution, less material in the tracking volume, and faster construction speed. At the same time, many design features of the sensors are driven by the requirement of minimizing the impact on the rest of the detector. Hence the target devices feature long pixels which are grouped to form a virtual strip with binary-encoded z position. The key performance aspects are radiation hardness compatibility with HL-LHC environment, as well as extraction of the full hit position with full-reticle readout architecture. To date, several test chips have been submitted using two different CMOS technologies. The AMS 350 nm is a high voltage CMOS process (HV-CMOS), that features the sensor bias of up to 120 V. The TowerJazz 180 nm high resistivity CMOS process (HR-CMOS) uses a high resistivity epitaxial layer to provide the depletion region on top of the substrate. We have evaluated passive pixel performance, and charge collection projections. The results strongly support the radiation tolerance of these devices to radiation dose of the HL-LHC in the strip tracker region. We also describe design features for the next chip submission that are motivated by our technology evaluation

Some features of the reproduction of fishes in parts of the Volga before and after flow regulation.

Conditions, times, duration and success of reproduction of fish in the Volga around Koz'modem'yansk (in the zone of the former Cheboksary reservoir) and in the upper part of Kuybyshev reservoir were studied. In years with a low spring runoff, spawning success is greater in the river than in the reservoir; in high-water years with a relatively stable water level in spring it may be higher in the reservoir than in the river. Differences were noted in the yield of young of different species depending on the spawning period.-from Sport Fishery Abstract

ДОСВІД ВИКОРИСТАННЯ ПРОМИСЛОВИХ КЛАСТЕРІВ ЯК ІНСТРУМЕНТУ ІННОВАЦІЙНОГО РОЗВИТКУ

It is shown in the article that within the territory for which the set of limited resources is characteristic, objectively there are groups of the cluster educations including both uniform and specific enterprises. It demands specification of separate provisions of the cluster theory of Porter. On the basis of synthesis of foreign experience authors made conclusions about possibility of its adaptation to conditions of Ukraine. В статье показано, что в пределах территории, для которой характерен набор ограниченных ресурсов, объективно существуют группы кластерных образований, включающих как однородные, так и специфические предприятия. Это требует уточнения отдельных положений кластерной теории Портера. На основе обобщения зарубежного опыта авторами сделаны выводы относительно возможности его адаптации к условиям Украины.  Устаттіпоказано, щовмежахтериторії, дляякоїхарактернийнабіробмеженихресурсів, об'єктивноіснуютьгрупикластернихутворень, щовключаютьякоднорідні, такіспецифічніпідприємства. Це вимагає уточнення окремих положень кластерної теорії Портера. На основі узагальнення зарубіжного досвіду авторами зроблені виводи відносно можливості його адаптації до умов України

Pulsational instability of yellow hypergiants

Instability of population I (X=0.7, Y=0.02) massive stars against radial oscillations during the post-main sequence gravitational contraction of the helium core is investigated. Initial stellar masses are in the range from 65M_\odot to 90M_\odot. In hydrodynamic computations of self-exciting stellar oscillations we assumed that energy transfer in the envelope of the pulsating star is due to radiative heat conduction and convection. The convective heat transfer was treated in the framework of the theory of time-dependent turbulent convection. During evolutionary expansion of outer layers after hydrogen exhaustion in the stellar core the star is shown to be unstable against radial oscillations while its effective temperature is Teff > 6700K for Mzams=65M_\odot and Teff > 7200K for mzams=90M_\odot. Pulsational instability is due to the \kappa-mechanism in helium ionization zones and at lower effective temperature oscillations decay because of significantly increasing convection. The upper limit of the period of radial pulsations on this stage of evolution does not exceed 200 day. Radial oscillations of the hypergiant resume during evolutionary contraction of outer layers when the effective temperature is Teff > 7300K for Mzams=65M_\odot and Teff > 7600K for Mzams=90M_\odot. Initially radial oscillations are due to instability of the first overtone and transition to fundamental mode pulsations takes place at higher effective temperatures (Teff > 7700K for Mzams=65M_\odot and Teff > 8200K for Mzams=90M_\odot). The upper limit of the period of radial oscillations of evolving blueward yellow hypergiants does not exceed 130 day. Thus, yellow hypergiants are stable against radial stellar pulsations during the major part of their evolutionary stage.Comment: 20 pages, 7 gigures. Accepted for publication in Astronomy Letter

Osteomalacia in practice of endocrinologist: etiology, pathogenesis, differential diagnosis with osteoporosis

Osteoporosis is the most common cause of low bone mineral density (BMD) and low-traumatic fractures in adults. However, differential diagnosis should also consider other causes of decreased BMD, including osteomalacia, as treatment for these conditions vary significantly. Osteomalacia is a systemic disorder characterized by decrease in bone strength due to of excessive accumulation of non-mineralized osteoid and uncoupling between bone matrix formation and mineralization. Osteomalacia in adults mostly develops due to severe vitamin D deficiency of any etiology, less often along with kidney pathology, mesenchymal tumors secreting fibroblast growth factor 23 or hereditary metabolic bone diseases. Clinical symptoms of osteomalacia are nonspecific and mostly manifest by generalized diffuse bone pain, muscle weakness, skeletal deformities and often go unnoticed at initial stage of the disease. Histomorphometric examination is the most accurate method of the diagnosis, which allows assessment of bone formation rate and calcification. The utmost priority of the treatment of osteomalacia of any etiology is the elimination of vitamin D deficiency, hypocalcemia, hypophosphatemia and prevention of bone deformities progression and muscle hypotension

ИСПОЛЬЗОВАНИЕ ПРОГРАММЫ ProCast ДЛЯ МОДЕЛИРОВАНИЯ ПРОЦЕССА ПОЛУЧЕНИЯ ОТЛИВОК ИЗ СПЛАВА TNM-B1 НА ОСНОВЕ АЛЮМИНИДА ТИТАНА ЛИТЬЕМ В КЕРАМИЧЕСКИЕ ФОРМЫ

The opportunity to simulate the process of titanium aluminide based TNM-B1 alloy casting production according to ProCast program is considered. Comparison of crystallization parameters obtained by means of ProCast and Thermo-Calc thermo-dynamic bases is made. The alloys available in ProCast base are shown to be more preferable for simulation. An estimation of conditional fluidity for different versions of TNM-B1 alloy composition is made; and it is shown that alloys should be alloyed by upper limit of admissible concentrations for reaching its maximum values. The material of a casting mold named «Corundum ceramics» (NITU «MISiS», Moscow) is proposed, the properties of which are distinct from those available in the base of ProCast foundry process computer simulation system.Рассмотрена возможность моделирования процесса получения отливок из сплава TNM-B1 на основе алюминида титана в программе ProCast. Проведено сравнение параметров кристаллизации, получаемых с помощью термодинамических баз ProCast и Thermo-Calc. Показано, что для моделирования предпочтительнее использовать сплавы, имеющиеся в базе ProCast. Для различных вариантов состава сплава TNM-B1 проведена оценка условной жидкотекучести и показано, что для достижения ее максимальных значений необходимо легировать сплавы по верхнему пределу допустимых концентраций. Предложен материал литейной формы, названный «Корундовая керамика» (НИТУ «МИСиС», г. Москва), свойства которого отличны от имеющихся в базе системы компьютерного моделирования литейных процессов ProCast

Instability of LBV-stars against radial oscillations

In this study we consider the nonlinear radial oscillations exciting in LBV--stars with effective temperatures 1.5e4 K <= Teff <= 3e4 K, bolometric luminosities 1.2e6 L_odot <= L <= 1.9e6 L_odot and masses 35.7 M_odot <= M <= 49.1 M_odot. Hydrodynamic computations were carried out with initial conditions obtained from evolutionary sequences of population I stars (X=0.7, Z=0.02) with initial masses from 70M_odot to 90 M_odot. All hydrodynamical models show instability against radial oscillations with amplitude growth time comparable with dynamical time scale of the star. Radial oscillations exist in the form of nonlinear running waves propagating from the boundary of the compact core to the upper boundary of the hydrodynamical model. The velocity amplitude of outer layers is of several hundreds of km/s while the bolometric light amplitude does not exceed 0.2 mag. Stellar oscillations are not driven by the kappa-mechanism and are due to the instability of the gas with adiabatic exponent close to the critical value Gamma_1 = 4/3 due to the large contribution of radiation in the total pressure. The range of the light variation periods (6 day <= P <= 31 day) of hydrodynamical models agrees with periods of microvariability observed in LBV--stars.Comment: 14 pages, 5 figures, submitted to Astronomy Letter

Radiation Hardness of Thin Low Gain Avalanche Detectors

Low Gain Avalanche Detectors (LGAD) are based on a n++-p+-p-p++ structure where an appropriate doping of the multiplication layer (p+) leads to high enough electric fields for impact ionization. Gain factors of few tens in charge significantly improve the resolution of timing measurements, particularly for thin detectors, where the timing performance was shown to be limited by Landau fluctuations. The main obstacle for their operation is the decrease of gain with irradiation, attributed to effective acceptor removal in the gain layer. Sets of thin sensors were produced by two different producers on different substrates, with different gain layer doping profiles and thicknesses (45, 50 and 80 um). Their performance in terms of gain/collected charge and leakage current was compared before and after irradiation with neutrons and pions up to the equivalent fluences of 5e15 cm-2. Transient Current Technique and charge collection measurements with LHC speed electronics were employed to characterize the detectors. The thin LGAD sensors were shown to perform much better than sensors of standard thickness (~300 um) and offer larger charge collection with respect to detectors without gain layer for fluences <2e15 cm-2. Larger initial gain prolongs the beneficial performance of LGADs. Pions were found to be more damaging than neutrons at the same equivalent fluence, while no significant difference was found between different producers. At very high fluences and bias voltages the gain appears due to deep acceptors in the bulk, hence also in thin standard detectors