Cooperative effects in nuclear excitation with coherent x-ray light

The interaction between super-intense coherent x-ray light and nuclei is studied theoretically. One of the main difficulties with driving nuclear transitions arises from the very narrow nuclear excited state widths which limit the coupling between laser and nuclei. In the context of direct laser-nucleus interaction, we consider the nuclear width broadening that occurs when in solid targets, the excitation caused by a single photon is shared by a large number of nuclei, forming a collective excited state. Our results show that for certain isotopes, cooperative effects may lead to an enhancement of the nuclear excited state population by almost two orders of magnitude. Additionally, an update of previous estimates for nuclear excited state population and signal photons taking into account the experimental advances of the x-ray coherent light sources is given. The presented values are an improvement by orders of magnitude and are encouraging for the future prospects of nuclear quantum optics.Comment: 22 pages, 4 figures, 5 tables; updated to the published version, one additional results tabl

ЭНЕРГЕТИЧЕСКАЯ ЭФФЕКТИВНОСТЬ СЛОЖНОЙ КОЛОННЫ ПРИ РАЗДЕЛЕНИИ ПРОДУКТОВ ПИРОЛИЗА В ЗАВИСИМОСТИ ОТ СОСТАВА ПИТАНИЯ

The dependence of the energy consumption decrease on the different feed composition for the separation of C4+ vapor cracking fraction by means of complex columns implementation is investigated. Distillation sequences consisting of simple columns and partially thermally coupled distillation columns are compared. Cases of direct and indirect separation for all the schemes are considered. In order to reduce capital cost and industrial areas the implementation of dividing wall columns was proposed. These dividing wall columns are the thermodynamic analogs of partially thermally coupled distillation flowsheets. Analysis of temperature, liquid and vapor profiles in the partially thermally coupled distillation sequence revealed that only one column in the original flowsheets requires a structural change when converting it to the partially thermally coupled configuration. It is shown that the complex columns provide energy consumption reduction in the reboilers by 3-60% as compared to conventional distillation schemes.Исследована зависимость снижения энергетических затрат на разделение смеси C4+ фракций продуктов пиролиза за счет применения сложных колонн для различного состава сырья. Рассмотрено ректификационное разделение как в последовательностях, состоящих из двухотборных колонн, так и в комплексах с частично связанными тепловыми и материальными потоками, полученных на их основе. Для всех вариантов схем исследованы режимы работы по первому и второму заданным разделениям. С целью снижения капитальных затрат и уменьшения занимаемых производственных площадей предложено использование колонн с перегородками, которые являются термодинамическими аналогами комплексов с частично связанными тепловыми и материальными потоками. Изучено распределение температур, потоков жидкости и пара по высоте колонн; на основе этого показано, что при переходе к комплексам с частично связанными тепловыми и материальными потоками только одна из колонн потребует конструктивных изменений. Выявлено, что использование сложных колонн обеспечивает снижение энергозатрат в кипятильниках на 3-60% относительно схем из простых колонн

ENERGy EFFICIENCy OF THE COMPLEX COLUMN FOR THE SEPARATION OF VAPOR CRACkING PRODUCTS UNDER THE DEPENDING ON FEED COMPOSITION

The dependence of the energy consumption decrease on the different feed composition for the separation of C4+ vapor cracking fraction by means of complex columns implementation is investigated. Distillation sequences consisting of simple columns and partially thermally coupled distillation columns are compared. Cases of direct and indirect separation for all the schemes are considered. In order to reduce capital cost and industrial areas the implementation of dividing wall columns was proposed. These dividing wall columns are the thermodynamic analogs of partially thermally coupled distillation flowsheets. Analysis of temperature, liquid and vapor profiles in the partially thermally coupled distillation sequence revealed that only one column in the original flowsheets requires a structural change when converting it to the partially thermally coupled configuration. It is shown that the complex columns provide energy consumption reduction in the reboilers by 3-60% as compared to conventional distillation schemes

Proposal for a scheme to generate a 10 TW power level, femtosecond X-ray pulses for bio-imaging of single protein molecules at the European XFEL

Crucial parameters for bio-imaging experiments are photon energy range, peak power and pulse duration. For a fixed resolution, the largest diffraction signals are achieved at the longest wavelength supporting that resolution. In order to perform these experiments at the European XFEL, we propose to use a novel configuration combining self-seeding and undulator tapering techniques with the emittance-spoiler method. Experiments at the LCLS confirmed the feasibility of these three techniques. Their combination allows obtaining a dramatic increase the XFEL output peak power and a shortening of the photon pulse duration to levels sufficient for performing bio-imaging of single protein molecules at the optimal photon-energy range between 3 keV and 5 keV. We show here that it is possible to achieve up to a 100-fold increase in peak-power of the X-ray pulses at the European XFEL: the X-ray beam would be delivered in 10 fs-long pulses with 50 mJ energy each at a photon energy around 4 keV. We confirm by simulations that one can achieve diffraction before destruction with a resolution of 0.25 nm resolution

Extension of Sase Bandwidth Up to 2% as a Way to Increase Number of Indexed Images for Protein Structure Determination by Femtosecond X-ray Nanocrystallography at the European XFEL

Experiments at the LCLS confirmed the feasibility of femtosecond nanocrystallography for protein structure determination at near-atomic resolution. These experiments rely on X-ray SASE pulses with a fewmicroradians angular spread, and about 0.2 % bandwidth. By indexing individual patterns and then summing all counts in all partial reflections for each index it is possible to extract the square modulus of the structurefactor. The number of indexed images and the SASE bandwidth are linked, as an increasing number of Bragg spots per individual image requires an increasing spectral bandwidth. This calls for a few percent SASEbandwidth. Based on start-to-end simulations of the European XFEL baseline, we demonstrate that it is possible to achieve up to a 10-fold increase of the electron energy chirp by strongly compressing a 0.25 nCelectron bunch. This allows for data collection with a 2 % SASE bandwidth, a few mJ radiation pulse energy and a few fs-pulse duration, which would increase the efficiency of protein determination at the European XFEL. We prove this concept with simulations of photosystem-I nanocrystals, with a size of about 300 nm