Spectrometers based on the magnetic adiabatic collimation followed by an electrostatic filter (MAC-E-filter) principle combine high angular acceptance with an excellent energy resolution. These ...features make MAC-E-filters very valuable for experiments where the kinetic energy of ions or electrons from rare processes has to be measured with utmost sensitivity and precision. Examples are direct neutrino mass experiments like KATRIN which investigate the energy of electrons in the endpoint region of the tritium
β
-spectrum. However, the MAC-E-filter is a very sharp energy high-pass filter but not a differential spectrometer. To determine a spectral shape of a charged particle source, different electric retarding potentials have to be used sequentially, reducing the statistics. In a previous work we have shown that the advantages of the standard MAC-E-filter can be combined with a measurement of the time-of-flight (TOF), allowing to determine spectral information over a certain energy range with one retarding potential only, with the corresponding gain in statistics. This TOF method requires one to know the start time of the charged particles, which is not always possible. Therefore, we propose a new method which does not require the determination of the start time and which we call “time-focusing time-of-flight” (tfTOF): by applying a time dependent acceleration and deceleration potential at a subsequent MAC-E-filter, an energy dependent post-bunching of the charged particles is achieved.
We present the idea and proof of principle measurements for an angular-selective active filter for charged particles. The motivation for the setup arises from the need to distinguish background ...electrons from signal electrons in a spectrometer of MAC-E filter type. While a large fraction of the background electrons exhibit predominantly small angles relative to the magnetic guiding field (corresponding to a low amount of kinetic energy in the motion component transverse to the field lines, in the following referred to as transverse energy) and pass the filter mostly unhindered, signal electrons from an isotropically emitting source interact with the active filter and are detected. The concept is demonstrated using a microchannel plate (MCP) as an active filter element. When correctly aligned with the magnetic field, electrons with a small transverse energy pass the channels of the MCP without interaction while electrons with large transverse energies hit the channel walls and trigger an avalanche of secondary electrons that is subsequently detected. Due to several drawbacks of MCPs for an actual transverse energy filter, an alternative detection technique using microstructured Si-PIN diodes is proposed.
We consider the construction of interval estimates for the parameters with one-sided constraints. We show that the so-called method of sensitivity limit yields a correct solution of the problem. ...Derived are the solutions for the cases of a continuous distribution with non-negative estimated parameter and a discrete distribution, specifically a Poisson process with background. For both cases, the best upper limit is constructed that accounts for the a priori information. Particular applications to the neutrino mass measurements, rare processes (neutrinoless double beta-decay etc.) searches and cosmic ray studies are discussed.
The concept of a “system” is analyzed. The basic properties of systems are established. It is revealed that all its elements must be interrelated and be in interaction; the system interacts with the ...external environment as a whole, and division in it occurs from whole to parts. It is concluded that with respect to geographical objects, these requirements are too stringent, because then there arises the need for mandatory implementation of all conditions inherent in systems. And this is not always possible, because the realization of goals in accordance with which the object is formed may require consideration of independent factors. It is shown that not all geographical and related objects—sociogeographical and geoecological—meet the requirements on classical systems, because some (and sometimes all) of their components (or influencing factors) are not mutually dependent. A virtual example of a problem is given, namely, selection of the optimal location of an object out of several alternatives, consisting of several groups of factors, illustrating the absence of direct links between some of the components of the object. It is proposed to call such objects “nonsystem” objects. In contrast to systems, for them it is possible to form the structure from the bottom up, from particular to general, combining, if necessary, the components of the object into groups. This makes it possible to consistently complicate the object of research as necessary. At the same time, a number of factors, such as seasonal factors, can change their importance over time, which leads to the transition of objects from the “system” to the “nonsystem” state, and vice versa. Factors the influence of which is spatially limited can lead to similar consequences. A graphical interpretation of the concepts of “system” and “nonsystem object” provided in the form of oriented graphs, the edges of which represent groups of components (influencing factors). With such an approach, systems can be considered as a special case of objects in which all components are interrelated. At the same time, systems can be components of complex nonsystem objects.
We develop the theory of spin light of neutrino in matter (SLI12) and include the effect of plasma influence on the emitted photon. We use the special technique based on exact solutions of particles ...wave equations in matter to perform all the relevant calculations, and track how the plasmon mass enters the process characteristics including the neutrino energy spectrum, SLI12 rate and power. The new feature it induces is the existence of the process threshold for which we have found the exact expression and the dependence of the rate and power on this threshold condition. The SLI12 spatial distribution accounting for the above effects has been also obtained. These results might be of interest in connection with the recently reported hints of ultra-high energy neutrinos E = 1 ADT 10 PeV observed by IceCube.
The results of four years of continuous investigations (from May 2015 through April 2019) of the elemental composition of the water of the Northern Dvina River are presented; the water sampling was ...performed monthly year around at two sites in the lower reaches. More than 50 major and trace elements were determined in filtered water (0.45-µm membrane filter) and in suspended matter on filters, as well as C
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on GF/F glass fiber filters. The ICP MS and AAS methods were applied. The most important outcome is that the average weighted concentrations of elements in the water discharge (dissolved forms) and in suspended matter discharge (suspended form) were obtained in contrast to most similar previous publications; the average weighted concentrations allowed us to consider these results to be the most close to real. The C
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and Fe concentrations in waters of the Northern Dvina River are three- to fivefold higher compared to the average concentrations of these elements in the rivers of the world. This has a natural explanation, which includes the features of the watershed basin (widespread distribution of wetlands). The presence or absence of a correlation between elements and organoferric colloids significantly determines their concentration. The average content of elements in riverine suspended matter is very similar to the global levels, except for organic carbon and P. The annual element discharge for every year of study and the four-year average for two forms of matter (dissolved and suspended) were calculated.
The key indicators of marine sediment genesis are the particle size distribution (PSD) and volume concentration of suspended particulate matter (SPM). However, their study is not widespread in ship ...oceanology research. This paper reviews experience in using the LISST-Deep laser particle size analyzer for the study of marine SPM in situ. We present the first data on the volume concentration and PSD of SPM in the Barents Sea obtained during the 75th cruise of the RV
Akademik Mstislav Keldysh
in June 2019. We carried out an assessment of the adequacy of information display on the polydisperse system composition of the Barents Sea water body, which contains particles of a wide particle size spectrum of differing genesis and shape. This paper gives a regression and correlation analysis of LISST-Deep data with a Wet Labs turbidity meter and Multisizer 3 Coulter Counter, as well as the SPM mass concentration measured by the membrane filtration technique. All of them demonstrated reliable correlations between characteristics of SPM of the Barents Sea. Their correlation and determination coefficients varied from 0.6 to 0.8. The laser diffractometer produces more detailed vertical distributions of marine SPM parameters than does a turbidity meter, especially for euphotic zones. We found a significant correlation of LISST-Deep data with the concentration of dissolved oxygen, which increases for coarse–silty and sandy fractions (47.7–92.6 and 92.6–250 µm, respectively). Also, there is a correlation with SPM composition between parameters as organic carbon concentration and phytoplankton pigments. These correlations give some indirect indications of SPM composition from laser diffractometer measurements.
The paper presents new data on concentrations and fluxes of organic carbon, iron, and manganese in waters of the mouth area of the Northern Dvina River. The work was conducted within the project ...“Northern Dvina River Marginal Filter Observatory” from May 2015 to May 2019 with monthly collection of water samples. Systematic determinations of the concentrations of the main carrier elements of many trace elements in dissolved and particulate forms were used to establish the average weighted of C
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, Fe, and Mn concentrations. The results of 4 years of systematic investigations established the main regularities of seasonal variations of dissolved and particulate forms of element concentrations and the relationships between. Significant variations were observed not only between concentrations but also between fluxes of elements in both forms. However, more than half the annual fluxes of all elements in all years studied was transported to the sea in the spring flood period. The results also demonstrated significant variations between element concentrations and their fluxes in different years. This is unsurprising, since even during the 4 years of investigations, the difference between water runoff and SPM fluxes in different years was up to, respectively, 1.4 and 2.6 times.
The article presents the results of studying the distribution and composition of dispersed sedimentary matter (suspended particulate matter, SPM) in the Barents Sea water column. The SPM distribution ...in the sea obeys the laws of circumcontinental (for surface distribution) and vertical zoning. The absolute values of the weight and volume concentrations of the SPM are low (on average, less than 0.5 mg/L and less than 0.6 mm
3
/L, respectively). The highest values of SPM parameters were noted in the Pechora Sea, southeasternmost part of the Barents, where the main role in sediment supply is played by coastal and bottom abrasion, as well Pechora River runoff. The vertical SPM distribution is characterized by surface and bottom peaks. Weakly expressed intrusion of the SPM-enriched nepheloid layer into deep layers was observed with a sharp drop in depth on the continental slope of the Bear Island Trench.
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