Time-of-flight spin-echo small-angle neutron scattering applied to biological cell nuclei

The organization of chromatin in the nuclei of rat lymphocyte was studied by time-of-flight spin-echo small-angle neutron scattering (ToF-SESANS). The procedures of the measurements in ToF and monochromatic SESANS modes were compared. It is shown that the sensitivity of the ToF method is significantly higher than that of the monochromatic mode....

CSPP1 stabilizes growing microtubule ends and damaged lattices from the luminal side

Microtubules are dynamic cytoskeletal polymers, and their organization and stability are tightly regulated by numerous cellular factors. While regulatory proteins controlling the formation of interphase microtubule arrays and mitotic spindles have been extensively studied, the biochemical mechanisms responsible for generating stable...

Small-angle neutron scattering (SANS) and spinecho SANS measurements reveal the logarithmic fractal structure of the large-scale chromatin organization in HeLa nuclei

This paper reports on the two-scale fractal structure of chromatin organization in the nucleus of the HeLa cell. Two neutron scattering methods, small-angle neutron scattering (SANS) and spin-echo SANS, are used to unambiguously identify the large-scale structure as being a logarithmic fractal with the correlation function (r) - ln(r/E). The...

Spin-echo small-angle neutron scattering study of the structure organization of the chromatin in biological cell

Spin-echo small-angle scattering (SESANS) technique is a method to measure the structure of materials from nano- to micrmeter length scales. This method could be important for studying the packaging of DNA in the eukaryotic cell. We measured the SESANS function from chicken erythrocyte nuclei which is well fitted by the exponential function G...

Additive scaling law for structural organization of chromatin in chicken erythrocyte nuclei

Small-angle neutron scattering (SANS) on nuclei of chicken erythrocytes demonstrates the cubic dependence of the scattering intensity Q−3 in the range of momentum transfer Q∈10−3–10−2nm−1. Independent spin-echo SANS measurements give the spin-echo function, which is well described by the exponential law in a range of sizes (3×102)–(3×104) nm....

Algorithm of the Computer Modelling and a SESANS Setup with Adiabatic RF-Flippers

We made software to simulate Larmor precession in a setup for SESANS with adiabatic/RF flippers in magnets, existing at PNPI. The final polarisation of a divergent “ribbon beam” of height 2 cm is calculated as a function of λ. For λ= 6 A, flippers 56 cm apart and RF frequency 1 MHz we find spin-echo length δ= 0.9 μm. We show numerically, how λ...

Magnetic topology of Co-based inverse opal-like structures

The magnetic and structural properties of a cobalt inverse opal-like crystal have been studied by a combination of complementary techniques ranging from polarized neutron scattering and superconducting quantum interference device (SQUID) magnetometry to x-ray diffraction. Microradian small-angle x-ray diffraction shows that the inverse opal-like...

Manifestation of the geometric phase in neutron spin-echo experiments

We show how the geometric (Berry’s) phase becomes manifest on adiabatic rotation of the polarization vector in the magnetic field configuration in the arms in a neutron spin echo (NSE) experiment.When the neutron beam used is monochromatic, a geometric phase collected in one spin-echo arm can be exactly compensated in the other arm either by an...

Chiral Paramagnetic Skyrmion-like Phase in MnSi

We present a comprehensive study of chiral fluctuations in the reference helimagnet MnSi by polarized neutron scattering and neutron spin echo spectroscopy, which reveals the existence of a completely left-handed and dynamically disordered phase. This phase may be identified as a spontaneous Skyrmion phase: it appears in a limited temperature...

Multilevel interference of a neutron wave

Four-wave neutron-resonance spin echo

Critical scattering of polarized neutrons in the invar Fe65Ni35 alloy

Neutron-multiwave-interference experiments with many resonance coils

Magnetic phase transition in disordered Fe-Ni alloys studied by means of small-angle neutron scattering and three-dimensional analysis of the neutron depolarization

Neutron-wave-interference experiments with two resonance coils

Neutron wave-interference experiments with adiabatic passage of neutron spin through resonant coils