Problems of long-term data storage

This paper is devoted to analysis of problems of long-term information storage. A short historical overview of the methods of long-term information storage is presented. The overview briefly covers a period from ancient times up to nowadays. The fundamental problems faced by both researchers and private companies working in the field of long-term data storage are highlighted. The main problems come along this long-term data storage, known as digital dark ages are shown. Different ways of overcoming them are revealed. It is shown that many scientific facilities successfully resolved the task of data corruption due to degradation over time and external influence. It is noted that the Institute for information recording, NAS of Ukraine is a research facility proposed and realized a way of overcoming the longevity of data carrier problem. The analysis of the principles of the work of «fast» memory is made, its variants are presented. The possibility of introducing the principles of «fast» visual memory on optical media is considered and discussed.Роботу присвячено аналізу проблем довготермінового зберігання інформації. Представлено короткий історичний огляд методів довготермінового зберігання інформації. Висвітлено фундамен-тальні проблеми, з якими стикаються як дослідники, так і приватні компанії, які працюють в області довготермінового зберігання даних. Показано шляхи подолання існуючих проблем довготермі-нового зберігання. Зроблено аналіз принципів роботи «швидкої» візуальної пам’яті, представлено її різновиди. Розглянуто можливість впровадження принципів «швидкої» пам’яті на оптичних носіях інформації.Работа посвящена анализу проблем долговременного хранения информации. Представлен короткий исторический обзор методов долговременного хранения информации. Освещены фундаментальные проблемы, с которыми сталкиваются как исследователи, так и частные компании, работающие в области долговременного хранения данных. Показаны пути преодоления существующих проблем долговременного хранения. Произведен анализ принципов работы «быстрой» визуальной памяти, представлены ее разновидности. Рассмотрена возможность внедрения принципов «быстрой» памяти на оптических носителях информации

Design of Nanostructured Luminofor Сoating for a Multi-Junction Solar Cell

Design of the highly efficient solar cells is a hot area of semiconductor physics and material science. One of the major concerns is a substantial shift between the solar radiation spectra and optical absorption spectra of a photoelectric transducer. A new method based on synthesis of luminophor layer functioning as a radiation converter was proposed. It’s shown that nanostructured pyrazoline coatings could convert the incoming solar radiation into the secondary optical radiation for optimal matching with the active spectral range of the solar cell. Results of the experimental investigation revealed high potential capabilities for optical properties engineering of the luminophor through laser annealing. It was found that produced samples of nanostructured organic composites are characterized by sufficiently enough spectral shift (200–400 nm) that can be varied by doping during synthesis, high quantum yield (near 80 %), and are enough stable under circumstances of intensive long term radiation.Зазначено, що розробка високоефективних сонячних елементів є актуальним напрямком як матеріалознавчої науки, так і фізики напівпровідників. Однією з найважливіших проблем, що потребують нагального вирішення, є значна невідповідність між спектром сонячного випромінювання і спектром поглинання фотоелемента. Запропоновано метод, що полягає в синтезі та нанесенні на поверхню фотоелемента люмінофорного шару, який функціонує як перетворювач електромагнітного випромінювання. Показано, що наноструктуроване піразолінове покриття здатне перетворювати падаюче сонячне випромінювання у вторинне оптичне випромінювання для оптимальної відповідності сонячного спектра та спектра поглинання фотоелемента. Результати експериментального дослідження показали широкі можливості у процесі створення такого типу покриття. Встановлено, що одержані наноструктуровані органічні композити характеризуються достатньою величиною спектрального зсуву (200 - 400 нм), що може варіюватися шляхом введення домішок у процесі синтезу люмінофору, високим квантовим виходом 80 % і є досить стабільними за умов довготривалого інтенсивного опромінення

High-density data recording via laser thermo-lithography and ion-beam etching

Pits 250 – 300 - nm wide were obtained on the surface of thin organic nanocomposite film using master-disc laser-burning station with 405 nm laser beam focused by 0.85 NA lens. The film with obtained pits was used as a mask for subsequent reactive ion-beam etching of glass substrate. Finally, 150 – 200-nm pits were performed on the substrate surface. Nanocomposite films were based on organic positive photoresist with a dye inclusions. This dye is characterized by wide absorption band within the spectral region 390–410 nm and can be evaporated by laser irradiation with the wavelength 405 n

Formation of submicron relief structures on the surface of sapphire substrates

An analysis of technologies that allow creating microrelief structures on the surface of sapphire substrates has been carried out. It is shown that the most effective method of forming relief structures with submicron dimensions is ion beam   etching through a protective mask formed by photolithography. The main problems in creating a microrelief on the surface of sapphire substrates are the removal of static electric charge in the process of ion beam  etching of the substrates, as well as obtaining a protective mask with windows of specified sizes, through which etching of the sapphire substrate is performed

Inclusive cross section and double helicity asymmetry for \pi^0 production in p+p collisions at sqrt(s)=200 GeV: Implications for the polarized gluon distribution in the proton

The PHENIX experiment presents results from the RHIC 2005 run with polarized proton collisions at sqrt(s)=200 GeV, for inclusive \pi^0 production at mid-rapidity. Unpolarized cross section results are given for transverse momenta p_T=0.5 to 20 GeV/c, extending the range of published data to both lower and higher p_T. The cross section is described well for p_T < 1 GeV/c by an exponential in p_T, and, for p_T > 2 GeV/c, by perturbative QCD. Double helicity asymmetries A_LL are presented based on a factor of five improvement in uncertainties as compared to previously published results, due to both an improved beam polarization of 50%, and to higher integrated luminosity. These measurements are sensitive to the gluon polarization in the proton, and exclude maximal values for the gluon polarization.Comment: 375 authors, 7 pages, 3 figures. Submitted to Phys. Rev. D, Rapid Communications. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

Dilepton mass spectra in p+p collisions at sqrt(s)= 200 GeV and the contribution from open charm

The PHENIX experiement has measured the electron-positron pair mass spectrum from 0 to 8 GeV/c^2 in p+p collisions at sqrt(s)=200 GeV. The contributions from light meson decays to e^+e^- pairs have been determined based on measurements of hadron production cross sections by PHENIX. They account for nearly all e^+e^- pairs in the mass region below 1 GeV/c^2. The e^+e^- pair yield remaining after subtracting these contributions is dominated by semileptonic decays of charmed hadrons correlated through flavor conservation. Using the spectral shape predicted by PYTHIA, we estimate the charm production cross section to be 544 +/- 39(stat) +/- 142(syst) +/- 200(model) \mu b, which is consistent with QCD calculations and measurements of single leptons by PHENIX.Comment: 375 authors from 57 institutions, 18 pages, 4 figures, 2 tables. Submitted to Physics Letters B. v2 fixes technical errors in matching authors to institutions. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

System Size and Energy Dependence of Jet-Induced Hadron Pair Correlation Shapes in Cu+Cu and Au+Au Collisions at sqrt(s_NN) = 200 and 62.4 GeV

We present azimuthal angle correlations of intermediate transverse momentum (1-4 GeV/c) hadrons from {dijets} in Cu+Cu and Au+Au collisions at sqrt(s_NN) = 62.4 and 200 GeV. The away-side dijet induced azimuthal correlation is broadened, non-Gaussian, and peaked away from \Delta\phi=\pi in central and semi-central collisions in all the systems. The broadening and peak location are found to depend upon the number of participants in the collision, but not on the collision energy or beam nuclei. These results are consistent with sound or shock wave models, but pose challenges to Cherenkov gluon radiation models.Comment: 464 authors from 60 institutions, 6 pages, 3 figures, 2 tables. Submitted to Physical Review Letters. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

Measurement of Bottom versus Charm as a Function of Transverse Momentum with Electron-Hadron Correlations in p+p Collisions at sqrt(s)=200 GeV

The momentum distribution of electrons from semi-leptonic decays of charm and bottom for mid-rapidity |y|<0.35 in p+p collisions at sqrt(s)=200 GeV is measured by the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) over the transverse momentum range 2 < p_T < 7 GeV/c. The ratio of the yield of electrons from bottom to that from charm is presented. The ratio is determined using partial D/D^bar --> e^{+/-} K^{-/+} X (K unidentified) reconstruction. It is found that the yield of electrons from bottom becomes significant above 4 GeV/c in p_T. A fixed-order-plus-next-to-leading-log (FONLL) perturbative quantum chromodynamics (pQCD) calculation agrees with the data within the theoretical and experimental uncertainties. The extracted total bottom production cross section at this energy is \sigma_{b\b^bar}= 3.2 ^{+1.2}_{-1.1}(stat) ^{+1.4}_{-1.3}(syst) micro b.Comment: 432 authors, 6 pages text, 3 figures. Submitted to Phys. Rev. Lett. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

Transverse-energy distributions at midrapidity in pp++pp, dd++Au, and Au++Au collisions at sNN=62.4\sqrt{s_{_{NN}}}=62.4--200~GeV and implications for particle-production models

Measurements of the midrapidity transverse energy distribution, d\Et/d\eta, are presented for $p$$+$$p$, $d$$+$Au, and Au$+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV and additionally for Au$+$Au collisions at $\sqrt{s_{_{NN}}}=62.4$ and 130 GeV. The d\Et/d\eta distributions are first compared with the number of nucleon participants $N_{\rm part}$, number of binary collisions $N_{\rm coll}$, and number of constituent-quark participants $N_{qp}$ calculated from a Glauber model based on the nuclear geometry. For Au$+$Au, \mean{d\Et/d\eta}/N_{\rm part} increases with $N_{\rm part}$, while \mean{d\Et/d\eta}/N_{qp} is approximately constant for all three energies. This indicates that the two component ansatz, $dE_{T}/d\eta \propto (1-x) N_{\rm part}/2 + x N_{\rm coll}$, which has been used to represent $E_T$ distributions, is simply a proxy for $N_{qp}$, and that the $N_{\rm coll}$ term does not represent a hard-scattering component in $E_T$ distributions. The $dE_{T}/d\eta$ distributions of Au$+$Au and $d$$+$Au are then calculated from the measured $p$$+$$p$ $E_T$ distribution using two models that both reproduce the Au$+$Au data. However, while the number-of-constituent-quark-participant model agrees well with the $d$$+$Au data, the additive-quark model does not.Comment: 391 authors, 24 pages, 19 figures, and 15 Tables. Submitted to Phys. Rev. C. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are publicly available at http://www.phenix.bnl.gov/papers.htm

Improved Measurement of Double Helicity Asymmetry in Inclusive Midrapidity pi^0 Production for Polarized p+p Collisions at sqrt(s)=200 GeV

We present an improved measurement of the double helicity asymmetry for pi^0 production in polarized proton-proton scattering at sqrt(s) = 200 GeV employing the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). The improvements to our previous measurement come from two main factors: Inclusion of a new data set from the 2004 RHIC run with higher beam polarizations than the earlier run and a recalibration of the beam polarization measurements, which resulted in reduced uncertainties and increased beam polarizations. The results are compared to a Next to Leading Order (NLO) perturbative Quantum Chromodynamics (pQCD) calculation with a range of polarized gluon distributions.Comment: 389 authors, 4 pages, 2 tables, 1 figure. Submitted to Phys. Rev. D, Rapid Communications. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm