The HARPS polarimeter

We recently commissioned the polarimetric upgrade of the HARPS spectrograph at ESO's 3.6-m telescope at La Silla, Chile. The HARPS polarimeter is capable of full Stokes spectropolarimetry with large sensitivity and accuracy, taking advantage of the large spectral resolution and stability of HARPS. In this paper we present the instrument design and its polarimetric performance. The first HARPSpol observations show that it can attain a polarimetric sensitivity of ~10^-5 (after addition of many lines) and that no significant instrumental polarization effects are present.Comment: To be published in ASP Conf Series, Solar Polarization Workshop

HARPS3 for a Roboticized Isaac Newton Telescope

We present a description of a new instrument development, HARPS3, planned to be installed on an upgraded and roboticized Isaac Newton Telescope by end-2018. HARPS3 will be a high resolution (R = 115,000) echelle spectrograph with a wavelength range from 380-690 nm. It is being built as part of the Terra Hunting Experiment - a future 10 year radial velocity measurement programme to discover Earth-like exoplanets. The instrument design is based on the successful HARPS spectrograph on the 3.6m ESO telescope and HARPS-N on the TNG telescope. The main changes to the design in HARPS3 will be: a customised fibre adapter at the Cassegrain focus providing a stabilised beam feed and on-sky fibre diameter ~ 1.4 arcsec, the implementation of a new continuous flow cryostat to keep the CCD temperature very stable, detailed characterisation of the HARPS3 CCD to map the effective pixel positions and thus provide an improved accuracy wavelength solution, an optimised integrated polarimeter and the instrument integrated into a robotic operation. The robotic operation will optimise our programme which requires our target stars to be measured on a nightly basis. We present an overview of the entire project, including a description of our anticipated robotic operation.Comment: 13 pages, 8 figures, SPIE conference proceeding

A unique infrared spectropolarimetric unit for CRIRES+

High-resolution infrared spectropolarimetry has many science applications in astrophysics. One of them is measuring weak magnetic fields using the Zeeman effect. Infrared domain is particularly advantageous as Zeeman splitting of spectral lines is proportional to the square of the wavelength while the intrinsic width of the line cores increases only linearly. Important science cases include detection and monitoring of global magnetic fields on solar-type stars, study of the magnetic field evolution from stellar formation to the final stages of the stellar life with massive stellar winds, and the dynamo mechanism operation across the boundary between fully- and partially-convective stars. CRIRES+ (the CRIRES upgrade project) includes a novel spectropolarimetric unit (SPU) based on polar- ization gratings. The novel design allows to perform beam-splitting very early in the optical path, directly after the tertiary mirror of the telescope (the ESO Very Large Telescope, VLT), minimizing instrumental polariza- tion. The new SPU performs polarization beam-splitting in the near-infrared while keeping the telescope beam mostly unchanged in the optical domain, making it compatible with the adaptive optics system of the CRIRES+ instrument. The SPU consists of four beam-splitters optimized for measuring circular and linear polarization of spectral lines in YJ and HK bands. The SPU can perform beam switching allowing to correct for throughput in each beam and for variations in detector pixel sensitivity. Other new features of CRIRES+, such as substantially increased wavelength coverage, stability and advanced data reduction pipeline will further enhance the sensitivity of the polarimetric mode. The combination of the SPU, CRIRES+ and the VLT is a unique facility for making major progress in understanding stellar activity. In this article we present the design of the SPU, laboratory measurements of individual components and of the whole unit as well as the performance prediction for the operation at the VLT

New responsive polymers and supramolecular systems - synthesis and characterization

This thesis deals with the synthesis and properties of new photochromic polymers, low-molecular compounds and their supramolecular complexes. The first chapter describes the goal and motivation of this work. The second chapter presents an overview of isomerization of photochromic groups, e.g. spiropyrans and azobenzenes, and their application in the design and synthesis of photochromic materials. The third chapter describes the preparation and properties of microgel-surfactant complexes, in which the surfactant molecules contain a photoisomerizable azo-group. For this purpose, microgels based on copolymers of vinylcaprolactam and vinylimidazole were neutralized with sulfonic acid containing surfactant molecules. In the structure of the wedge-shaped surfactant molecules three long-chain alkyl groups are connected with a sulfonated azobenzene unit via an ester group. The alkyl chain contains 8 or 12 carbon atoms. The ionic binding of the surfactants to the microgels has a mutual influence. On the one hand, the micelle formation of the microgel-bound surfactants is altered compared to freely dissolved surfactants. On the other hand, the solubility behavior of the surfactants changes. These association and aggregate formation processes can in turn be influenced by the switchability of the surfactants under irradiation. The results show that the increase of the degree of neutralization of the vinylimidazole groups leads to the increase of the activation energy of the cis-trans-transition of the azobenzene groups. The activation energy also depends on the chain length. The longer the chain, the higher the activation energy. These effects result from 1) aggregation of wedge-shaped groups 2) low degree of neutralization of the vinylimidazole groups (no possibility to form microdomains). It has also been shown that the modification with the surfactant molecules has an influence on volume phase transitions of the microgels. While the thermal shrinkage behavior at low degrees of neutralization (25%) was only slightly less pronounced than that of the unmodified microgels, an increased degree of neutralization significantly affected the temperature dependence and led to the reduction in the hydrodynamic radius. The samples with the degree of neutralization of 100% further showed the decrease of the hydrodynamic radius: with the surfactant with dodecyl groups, the microgels largely lose their thermal sensitivity, while the increase of the transition temperature was observed for the surfactants with shorter alkyl chains. Chapter 4 deals with the domain formation of pure surfactant molecules. Under dry conditions and with low water content, the surfactant molecules form inverse micelles, which can also adopt a cylindrical structure. In this chapter the dependence of the structure on the water content was systematically investigated. With increasing relative air humidity (RH), the amount of absorbed water increases significantly for the surfactant with dodecyl chains, unlike in comparison with one with octyl groups. In the previous case, water sorption is accompanied by a significant increase in ion conductivity and a phase transition. In particular, an increase in RH leads to a transition from a lamellar to a columnar phase; this results in the formation of one-dimensional water channels along the axis of the supramolecular columns. In the case of the molecules with shorter alkyl chains, the lamellar phase exists over the entire RH range with prominent swelling at high RH values, which then also lead to a two-dimensional water channel structure. NMR diffusometry was used to address the molecular mobility in the lyotropic mesophases of the wedge-shaped amphiphilic sulfonate molecules. Chapter 5 focuses on the design, synthesis, and investigation of core-shell nanoparticles that contain spiropyran groups. The particles were synthesized using a two-stage polymerization procedure: 1) preparation of a spiropyran-containing polystyrene-based core via emulsion polymerization and 2) seed polymerization of N-isopropylacrylamide to build up a thermosensitive shell. This synthetic approach provides a simple method for the preparation of monodisperse particles with up to 4 mol.-% of spiropyran groups. The incorporation of such groups renders the polystyrene core pH-sensitive, that is expressed in the blue shift of the absorbance by adding acid, and UV-responsive: irradiation with light of 365 nm wavelength leads to isomerization from the spiropyran isomer to the merocyanine form, which is stable for up to 12 hours at room temperature. In addition, the formation of the merocyanine group is accompanied by both a significantly increasing absorbance in the range of 450-510 nm and an increase of the hydrodynamic radius of the particles through the formation of a solvation envelope. The presence of the poly-N-isopropylacrylamide shell makes the nanoparticles thermosensitive: their temperature of the volume-phase transition is 33° C. This chapter clearly shows the new approach to the synthesis of nanoparticles with multisensory properties. Overall, the work presented here describes a couple of interesting examples, where the sensitivity of different types to stimuli of different origins (temperature, pH and light) can be combined in multifunctional materials, therefore, there is great potential for their use in nanotechnolog

Остеосинтез кісток кінцівок у пацієнтів з післятравматичною ішемією в різні періоди ішемічного процесу

The article analyses results of osteosynthesis of extremity bones in conditions of post-traumatic ischaemia in 94 patients. Indications for treating fractures with a definite technique of osteosynthesis were elaborated depending upon the period of the ischaemic process and the degree of ischaemia severity. Thus, in local hypertensive ischaemic syndrome, excellent results of treatment were obtained with external fixation by means of device techniques; consolidations of fractures were achieved in 75 % of cases. When treating complications of fracture consolidation during the acute and reactive-restorative periods of ischaemic contracture, preference was given to device techniques of fixation and osteosynthesis with plates, thereby making it possible to restore bone integrity in 100 % of cases. Complex bone deformities during the residual period of ischaemic contracture were mostly treated by means of combined osteosynthesis.В статье представлен анализ результатов остеосинтеза костей конечностей в условиях посттрав­матической ишемии у 94 пациентов. Разработаны показания к лечению переломов определенным методом остеосинтеза, исходя из периода ишемического процесса и степени тяжести ишемии. Так, при местном гипертензивном ишемическом синдроме отличные результаты лечения были достигнуты при использовании наружной фиксации аппаратными методами, сращение перелома зафиксировано в 75 % случаев. При лечении осложнений сращения переломов в остром и реактивно-восстановительном периодах ишемической контрактуры предпочтение отдавали аппаратным методам фиксации и остеосинтезу пластинами, что позволило восстановить целостность костей у 100 % пострадавших. Для лечения сложных деформаций костей в резидуальном периоде ишемической контрактуры в основном использовали комбинированный остеосинтез.У статті проаналізовані результати остеосинтезу кісток кінцівок в умовах післятравматичної ішемії у 94 пацієнтів. Розроблені показання до лікування переломів певним методом остеосинтезу відповідно до періоду ішемічного процесу і ступеня тяжкості ішемії. Так, за умов місцевого гіпертензивного ішемічного синдрому відмінні результати лікування були досягнуті за умов використання зовнішньої фіксації апаратними методами, зрощення перелому зафіксовано в 75 % випадків. Під час лікування ускладнень зрощення переломів в гострому та реактивно-відновному періодах ішемічної контрактури перевагу віддавали апаратним методам фіксації і остеосинтезу пластинами, що давало змогу відновити цілісність кісток у 100 % постраждалих. Для лікування складних деформацій кісток в резидуальному періоді ішемічної контрактури в основному використовували комбінований остеосинтез

Electronically driven neutrons synthesis-generator with the magneto-optical flow seal

We develop the description of a neutron generator construction for the synthesis of light nuclei. The design of the neutron generator with plasma target is given together with a description of the types of nuclear reactions that are implemented in it. The brief theoretical description of the ion multiphase flow in the synthesis generator is considered

Electronically driven neutrons synthesis-generator with the magneto-optical flow seal

We develop the description of a neutron generator construction for the synthesis of light nuclei. The design of the neutron generator with plasma target is given together with a description of the types of nuclear reactions that are implemented in it. The brief theoretical description of the ion multiphase flow in the synthesis generator is considered