Application of Portable Raman Spectrometers for Rapid Production Control and Analysis at the Point Of-Need

Directory of Open Access Journals (Sweden)

Voyevoda, V.M.

2014-03-01

Full Text Available Basic theory of Raman spectroscopy and its application in various fields are described. A world leader in high-tech in s truments, Thermo Fіsher Scіentіfіc designed a series of portable Raman spectrometers for a broad range of applications.

Performance Assessment of a Plate Beam Splitter for Deep-Ultraviolet Raman Measurements with a Spatial Heterodyne Raman Spectrometer.

Science.gov (United States)

Lamsal, Nirmal; Angel, S Michael

2017-06-01

In earlier works, we demonstrated a high-resolution spatial heterodyne Raman spectrometer (SHRS) for deep-ultraviolet (UV) Raman measurements, and showed its ability to measure UV light-sensitive compounds using a large laser spot size. We recently modified the SHRS by replacing the cube beam splitter (BS) with a custom plate beam splitter with higher light transmission, an optimized reflectance/transmission ratio, higher surface flatness, and better refractive index homogeneity than the cube beam splitter. Ultraviolet Raman measurements were performed using a SHRS modified to use the plate beam splitter and a matching compensator plate and compared to the previously described cube beam splitter setup. Raman spectra obtained using the modified SHRS exhibit much higher signals and signal-to-noise (S/N) ratio and show fewer spectral artifacts. In this paper, we discuss the plate beam splitter SHRS design features, the advantages over previous designs, and discuss some general SHRS issues such as spectral bandwidth, S/N ratio characteristics, and optical efficiency.

Chemical Characterization of Nuclear Materials: Development a New Combined X-Ray Fluorescence and Raman Spectrometer

International Nuclear Information System (INIS)

Szaloki, I.; Gerenyi, A.

2015-01-01

New mobile analytical device based on combination of X-ray fluorescence and Raman spectrometer has been developed for prompt and quantitative characterization of chemical component from Al to U in nuclear waste or undeclared materials. The excitation source of the X-ray fluorescence spectrometer is an air-cooled X-ray tube with Ag transmission anode. For collection of secondary X-ray photons and data processing, a compact Amptek X-ray detector system is applied with silicon drift X-ray detector. The XRF system operates in confocal mode with focal volume around 1-4 mm 3 . Varying the geometrical position and orientation of the sample optional part of its surface can be analyzed. The Raman unit includes thermoelectrically cooled laser source having 500 mW power at wavelength 785 nm. In order to obtain spectral information from sample surface a reflection-type probe is connected by optical fibres to the Raman spectrometer. A mini focusing optics is set up to the sensor-fibre that provides the system to operate as confocal optical device in reflection mode. The XRF spectrometer with X-ray detector, Raman probe and X-ray tube are mechanically fixed and hermetically connected to an aluminium chamber, which can be optionally filled with helium. The chamber is mounted on a vertical stage that provides moving it to the sample surface. A new model and computer code have been developed for XRF quantitative analysis which describes the mathematical relationship between the concentration of sample elements and their characteristic X-ray intensities. For verification of the calculations standard reference alloy samples were measured. The results was in good agreement with certified concentrations in range of 0.001-100 w%. According to these numerical results this new method is successfully applicable for quick and non-destructive quantitative analysis of waste materials without using standard samples. (author)

Colonization of Snow by Microorganisms as Revealed Using Miniature Raman Spectrometers - Possibilities for Detecting Carotenoids of Psychrophiles on Mars?

Science.gov (United States)

Jehlička, Jan; Culka, Adam; Nedbalová, Linda

2016-12-01

We tested the potential of a miniaturized Raman spectrometer for use in field detection of snow algae pigments. A miniature Raman spectrometer, equipped with an excitation laser at 532 nm, allowed for the detection of carotenoids in cells of Chloromonas nivalis and Chlamydomonas nivalis at different stages of their life cycle. Astaxanthin, the major photoprotective pigment, was detected in algal blooms originating in snows at two alpine European sites that differed in altitude (Krkonoše Mts., Czech Republic, 1502 m a.s.l., and Ötztal Alps, Austria, 2790 m a.s.l.). Comparison is made with a common microalga exclusively producing astaxanthin (Haematococcus pluvialis). The handheld Raman spectrometer is a useful tool for fast and direct field estimations of the presence of carotenoids (mainly astaxanthin) within blooms of snow algae. Application of miniature Raman instruments as well as flight prototypes in areas where microbes are surviving under extreme conditions is an important stage in preparation for successful deployment of this kind of instrumentation in the framework of forthcoming astrobiological missions to Mars.

Using portable Raman spectrometers for the identification of organic compounds at low temperatures and high altitudes: exobiological applications.

Science.gov (United States)

Jehlicka, J; Edwards, H G M; Culka, A

2010-07-13

Organic minerals, organic acids and NH-containing organic molecules represent important target molecules for astrobiology. Here, we present the results of the evaluation of a portable hand-held Raman spectrometer to detect these organic compounds outdoors under field conditions. These measurements were carried out during the February-March 2009 winter period in Austrian Alpine sites at temperatures ranging between -5 and -25 degrees C. The compounds investigated were detected under field conditions and their main Raman spectral features were observed unambiguously at their correct reference wavenumber positions. The results obtained demonstrate that a miniaturized Raman spectrometer equipped with 785 nm excitation could be applied with advantage as a key instrument for investigating the presence of organic minerals, organic acids and nitrogen-containing organic compounds outdoors under terrestrial low-temperature conditions. Within the payload designed by ESA and NASA for several missions focusing on Mars, Titan, Europa and other extraterrestrial bodies, Raman spectroscopy can be proposed as an important non-destructive analytical tool for the in situ identification of organic compounds relevant to life detection on planetary and moon surfaces or near subsurfaces.

Using a portable Raman spectrometer to detect carotenoids of halophilic prokaryotes in synthetic inclusions in NaCl, KCl, and sulfates.

Science.gov (United States)

Jehlička, Jan; Culka, Adam; Mana, Lilly; Oren, Aharon

2018-05-03

Cell suspensions of the haloarchaea Halorubrum sodomense and Halobacterium salinarum and the extremely halophilic bacterium Salinibacter ruber (Bacteroidetes) in saturated solutions of chlorides and sulfates (NaCl, KCl, MgSO 4 ·7H 2 O, K 2 SO 4 , and (NH 4 )Al(SO 4 ) 2 ·12H 2 O) were left to evaporate to produce micrometric inclusions in laboratory-grown crystals. Raman spectra of these pinkish inclusions were obtained using a handheld Raman spectrometer with green excitation (532 nm). This portable instrument does not include any microscopic tool. Acceptable Raman spectra of carotenoids were obtained in the range of 200-4000 cm -1 . This detection achievement was related to the mode of illumination and collection of scattered light as well as due to resonance Raman enhancement of carotenoid signals under green excitation. The position of diagnostic Raman carotenoid bands corresponds well to those specific carotenoids produced by a given halophile. To our best knowledge, this is the first study of carotenoids included in the laboratory in crystalline chlorides and sulfates, using a miniature portable Raman spectrometer. Graphical abstract ᅟ.

The research of data acquisition system for Raman spectrometer

Science.gov (United States)

Cui, Xiao; Guo, Pan; Zhang, Yinchao; Chen, Siying; Chen, He; Chen, Wenbo

2011-11-01

Raman spectrometer has been widely used as an identification tool for analyzing material structure and composition in many fields. However, Raman scattering echo signal is very weak, about dozens of photons at most in one laser plus signal. Therefore, it is a great challenge to design a Raman spectrum data acquisition system which could accurately receive the weak echo signal. The system designed in this paper receives optical signals with the principle of photon counter and could detect single photon. The whole system consists of a photoelectric conversion module H7421-40 and a photo counting card including a field programmable gate array (FPGA) chip and a PCI9054 chip. The module H7421-40 including a PMT, an amplifier and a discriminator has high sensitivity on wavelength from 300nm to 720nm. The Center Wavelength is 580nm which is close to the excitation wavelength (532nm), QE 40% at peak wavelength, Count Sensitivity is 7.8*105(S-1PW-1) and Count Linearity is 1.5MHZ. In FPGA chip, the functions are divided into three parts: parameter setting module, controlling module, data collection and storage module. All the commands, parameters and data are transmitted between FPGA and computer by PCI9054 chip through the PCI interface. The result of experiment shows that the Raman spectrum data acquisition system is reasonable and efficient. There are three primary advantages of the data acquisition system: the first one is the high sensitivity with single photon detection capability; the second one is the high integrated level which means all the operation could be done by the photo counting card; and the last one is the high expansion ability because of the smart reconfigurability of FPGA chip.

Heavy-ion microbeam system at JAEA-Takasaki for microbeam biology

International Nuclear Information System (INIS)

Funayama, Tomoo; Wada, Seiichi; Yokota, Yuichiro

2008-01-01

Research concerning cellular responses to low dose irradiation, radiation-induced bystander effects, and the biological track structure of charged particles has recently received particular attention in the field of radiation biology. Target irradiation employing a microbeam represents a useful means of advancing this research by obviating some of the disadvantages associated with the conventional irradiation strategies. The heavy-ion microbeam system at Japan Atomic Energy Agency (JAEA)-Takasaki, which was planned in 1987 and started in the early 1990's, can provide target irradiation of heavy charged particles to biological material at atmospheric pressure using a minimum beam size 5 μm in diameter. A variety of biological material has been irradiated using this microbeam system including cultured mammalian and higher plant cells, isolated fibers of mouse skeletal muscle, silkworm (Bombyx mori) embryos and larvae, Arabidopsis thaliana roots, and the nematode Caenorhabditis elegans. The system can be applied to the investigation of mechanisms within biological organisms not only in the context of radiation biology, but also in the fields of general biology such as physiology, developmental biology and neurobiology, and should help to establish and contribute to the field of 'microbeam biology'. (author)

Time domain diffuse Raman spectrometer based on a TCSPC camera for the depth analysis of diffusive media.

Science.gov (United States)

Konugolu Venkata Sekar, S; Mosca, S; Tannert, S; Valentini, G; Martelli, F; Binzoni, T; Prokazov, Y; Turbin, E; Zuschratter, W; Erdmann, R; Pifferi, A

2018-05-01

We present a time domain diffuse Raman spectrometer for depth probing of highly scattering media. The system is based on, to the best of our knowledge, a novel time-correlated single-photon counting (TCSPC) camera that simultaneously acquires both spectral and temporal information of Raman photons. A dedicated non-contact probe was built, and time domain Raman measurements were performed on a tissue mimicking bilayer phantom. The fluorescence contamination of the Raman signal was eliminated by early time gating (0-212 ps) the Raman photons. Depth sensitivity is achieved by time gating Raman photons at different delays with a gate width of 106 ps. Importantly, the time domain can provide time-dependent depth sensitivity leading to a high contrast between two layers of Raman signal. As a result, an enhancement factor of 2170 was found for our bilayer phantom which is much higher than the values obtained by spatial offset Raman spectroscopy (SORS), frequency offset Raman spectroscopy (FORS), or hybrid FORS-SORS on a similar phantom.

High-sensitivity Raman spectrometer to study pristine and irradiated interstellar ice analogs.

Science.gov (United States)

Bennett, Chris J; Brotton, Stephen J; Jones, Brant M; Misra, Anupam K; Sharma, Shiv K; Kaiser, Ralf I

2013-06-18

We discuss the novel design of a sensitive, normal-Raman spectrometer interfaced to an ultra-high vacuum chamber (5 × 10(-11) Torr) utilized to investigate the interaction of ionizing radiation with low temperature ices relevant to the solar system and interstellar medium. The design is based on a pulsed Nd:YAG laser which takes advantage of gating techniques to isolate the scattered Raman signal from the competing fluorescence signal. The setup incorporates innovations to achieve maximum sensitivity without detectable heating of the sample. Thin films of carbon dioxide (CO2) ices of 10 to 396 nm thickness were prepared and characterized using both Fourier transform infrared (FT-IR) spectroscopy and HeNe interference techniques. The ν+ and ν- Fermi resonance bands of CO2 ices were observed by Raman spectroscopy at 1385 and 1278 cm(-1), respectively, and the band areas showed a linear dependence on ice thickness. Preliminary irradiation experiments are conducted on a 450 nm thick sample of CO2 ice using energetic electrons. Both carbon monoxide (CO) and the infrared inactive molecular oxygen (O2) products are readily detected from their characteristic Raman bands at 2145 and 1545 cm(-1), respectively. Detection limits of 4 ± 3 and 6 ± 4 monolayers of CO and O2 were derived, demonstrating the unique power to detect newly formed molecules in irradiated ices in situ. The setup is universally applicable to the detection of low-abundance species, since no Raman signal enhancement is required, demonstrating Raman spectroscopy as a reliable alternative, or complement, to FT-IR spectroscopy in space science applications.

Development of micro-optics for high-resolution IL spectroscopy with a proton microbeam probe

International Nuclear Information System (INIS)

Kada, Wataru; Satoh, Takahiro; Yokoyama, Akihito; Koka, Masashi; Kamiya, Tomihiro

2014-01-01

Confocal optics for ion luminescence (IL) was developed for the precise analysis of the chemical composition of microscopic targets with an external proton microbeam probe. Anti-reflection-coated confocal micro-lens optics with an effective focus area of approximately 800 × 800 μm was installed on the microbeam line of a single-ended accelerator. Chromatic aberrations of the confocal optics were examined at wavelengths of 300–900 nm. An electrically-cooled back-thinned charge coupled device spectrometer with a wavelength resolution of 0.5 nm was used for the microscopic spectroscopy and IL imaging of microscopic mineral targets. Simultaneous microscopic IL and micro-PIXE analysis were performed using an external 3 MeV H + microbeam with a current of less than 100 pA. A spectral resolution of 3 nm was achieved for a single IL peak which corresponded to Cr 3+ impurities in a single-crystal of aluminum oxide. The use of IL spectroscopy and imaging for aerosol targets revealed microscopic distributions of the chemical and elemental composition in the atmosphere

6th International Microbeam Workshop

Energy Technology Data Exchange (ETDEWEB)

Dr Kevin M. Prise

2004-01-01

The extended abstracts which are submitted here present a summary of the proceedings of the 6th International Workshop/12th LH Gray Workshop: Microbeam Probes of Cellular Radiation Response, held at St. Catherine's College, University of Oxford, UK on March, 29th-31st, 2003. In 1993 the 4th LH Gray Workshop entitled ''Microbeam Probes of Cellular Radiation Response'' was held at the Gray Cancer Institute in Northwood. This was organized by Prof BD Michael, Dr M. Folkard and Dr KM Prise and brought together 40 participants interested in developing and applying new microbeam technology to problems in radiation biology (1). The workshop was an undoubted success and has spawned a series of subsequent workshops every two years. In the past, these workshops have been highly successful in bringing together groups interested in developing and applying micro-irradiation techniques to the study of cell and tissue damage by ionizing radiations. Following the first microbeam workshop, there has been a rapid growth in the number of centres developing radiobiology microbeams, or planning to do so and there are currently 15-20 worldwide. Much of the recent research using microbeams has used them to study low-dose effects and ''non-targeted'' responses such bystander effects, genomic instability and adaptive responses. The goal of the 6th workshop was to build on our knowledge of the development of microbeam approaches and the application to radiation biology in the future with the meeting stretching over a 3 day period. Over 80 participants reviewed the current state of radiobiology microbeam research worldwide and reported on new technological developments both in the fields of physics and biology.

Production and applications of positron microbeams

International Nuclear Information System (INIS)

Brandes, G.R.; Canter, K.F.; Horsky, T.N.; Lippel, P.H.; Mills, A.P. Jr.

1989-01-01

The production of a positron microbeam using the high-brightness beam developed at Brandeis University and possible applications of this microbeam to spatially resolved defect studies and positron microscopy are reviewed. The high-brightness beam consists of a W(110) primary moderator and two remoderation stages which provide a 500-fold increase in brightness. With this brightness increase and microbeam optics, we are able to form a 12 μm FWHM beam (48 mrad pencil half-angle) at 5 keV beam energy. The well characterised small-diameter beam is particularly adaptable for determining defect concentration and structure, both laterally and in a depth-profiling mode. In the case of a transmission positron microscope or a positron re-emission microscope operating in a high-magnification mode, efficient image formation requires the use of a microbeam to maximise the number of positrons in the area being imaged. Results of the scanning microbeam tests and the application of a microbeam to positron microscopy and defect studies are reviewed. (author)

Surface enhanced raman spectroscopy on chip

DEFF Research Database (Denmark)

Hübner, Jörg; Anhøj, Thomas Aarøe; Zauner, Dan

2007-01-01

In this paper we report low resolution surface enhanced Raman spectra (SERS) conducted with a chip based spectrometer. The flat field spectrometer presented here is fabricated in SU-8 on silicon, showing a resolution of around 3 nm and a free spectral range of around 100 nm. The output facet...... is projected onto a CCD element and visualized by a computer. To enhance the otherwise rather weak Raman signal, a nanosurface is prepared and a sample solutions is impregnated on this surface. The surface enhanced Raman signal is picked up using a Raman probe and coupled into the spectrometer via an optical...... fiber. The obtained spectra show that chip based spectrometer together with the SERS active surface can be used as Raman sensor....

A Raman Spectrometer for the ExoMars 2020 Rover

Science.gov (United States)

Moral, A. G.; Rull, F.; Maurice, S.; Hutchinson, I.; Canora, C. P.; Seoane, L.; Rodríguez, P.; Canchal, R.; Gallego, P.; Ramos, G.; López, G.; Prieto, J. A. R.; Santiago, A.; Santamaría, P.; Colombo, M.; Belenguer, T.; Forni, O.

2017-09-01

The Raman project is devoted to the development of a Raman spectrometer and the support science associated for the rover EXOMARS mission to be launched in 2020. ExoMars is a double mission with two different launch opportunities, first one launched in March 2016 allowed to put in orbit the TGO with the communication system for the next mission. And the second one in 2020, deploying a rover which includes for the first time in the robotic exploration of Mars, a drill capable to obtain samples from the subsurface up to 2 meters depth. These samples will be crushed into a fine powder and delivered to the analytical instruments suite inside the rover by means of a dosing station. The EQM has been already qualified under a very demanding thermo mechanical environment, and under EMC tests, finally achieving required scientific performances. The RLS Engineering and Qualification Model has been manufactured and is expected to be delivered by May 2017, after a full qualification testing campaign developed during 2016 Q4, and 2017 Q1. It will finally delivered to ESA, by July 2017. December 2017 at TAS-I premises will do RLS FM delivery to ESA, for its final integration on the ExoMars 2020 Rover.

Raman spectroscopy of gases with a Fourier transform spectrometer: the spectrum of D2

International Nuclear Information System (INIS)

Jennings, D.E.; Weber, A.; Brault, J.W.

1986-01-01

A high-resolution Fourier transform spectrometer (FTS) has been used to record spontaneous incoherent laser Raman spectra of gases. The resolution, sensitivity, calibration accuracy, and spectral coverage achieved in these spectra demonstrate the viability of the FTS for Raman spectroscopy. Measurements from a spectrum of D 2 containing both v = 0-0 and v = 1-0 transitions were fitted to the Dunham expansion of the vibration--rotation energy levels. The coefficients are (in cm -1 ) Y 10 = 2993.6060(67), Y 01 = 30.4401 (89), Y 11 = -1.0538(17), Y 02 = -0.011590(41), Y 12 = 2.02(80) x 10 -4 , and Y 03 = 5.83(11) x 10 -6 . Errors in parentheses are one standard deviation

Focus small to find big - the microbeam story.

Science.gov (United States)

Wu, Jinhua; Hei, Tom K

2017-08-29

Even though the first ultraviolet microbeam was described by S. Tschachotin back in 1912, the development of sophisticated micro-irradiation facilities only began to flourish in the late 1980s. In this article, we highlight significant microbeam experiments, describe the latest microbeam irradiator configurations and critical discoveries made by using the microbeam apparatus. Modern radiological microbeams facilities are capable of producing a beam size of a few micrometers, or even tens of nanometers in size, and can deposit radiation with high precision within a cellular target. In the past three decades, a variety of microbeams has been developed to deliver a range of radiations including charged particles, X-rays, and electrons. Despite the original intention for their development to measure the effects of a single radiation track, the ability to target radiation with microbeams at sub-cellular targets has been extensively used to investigate radiation-induced biological responses within cells. Studies conducted using microbeams to target specific cells in a tissue have elucidated bystander responses, and further studies have shown reactive oxygen species (ROS) and reactive nitrogen species (RNS) play critical roles in the process. The radiation-induced abscopal effect, which has a profound impact on cancer radiotherapy, further reaffirmed the importance of bystander effects. Finally, by targeting sub-cellular compartments with a microbeam, we have reported cytoplasmic-specific biological responses. Despite the common dogma that nuclear DNA is the primary target for radiation-induced cell death and carcinogenesis, studies conducted using microbeam suggested that targeted cytoplasmic irradiation induces mitochondrial dysfunction, cellular stress, and genomic instability. A more recent development in microbeam technology includes application of mouse models to visualize in vivo DNA double-strand breaks. Microbeams are making important contributions towards our

Raman Spectroscopy with simple optic components; Espectrometria Raman con componentes opticos simples

Energy Technology Data Exchange (ETDEWEB)

Mendoza, Mario; Cunya, Eduardo; Olivera, Paula [Direccion de Investigacion y Desarrollo, Instituto Peruano de Energia Nuclear, Lima (Peru)

2014-07-01

Raman Spectroscopy is .a high resolution photonics technique that provides chemical and structural information of almost any material, organic or inorganic compound. In this report we describe the implementation of a system based on the principle of Raman scattering, developed to analyze solid samples. The spectrometer integrates an optical bench coupled to an optical fiber and a green laser source of 532 nm. The spectrometer was tested obtaining the Naphthalene and the Yellow 74 Pigment Raman patterns. (authors).

Active mems microbeam device for gas detection

KAUST Repository

Bouchaala, Adam M.

2017-10-05

Sensors and active switches for applications in gas detection and other fields are described. The devices are based on the softening and hardening nonlinear response behaviors of microelectromechanical systems (MEMS) clamped-clamped microbeams. In that context, embodiments of gas-triggered MEMS microbeam sensors and switches are described. The microbeam devices can be coated with a Metal-Organic Framework to achieve high sensitivity. For gas sensing, an amplitude-based tracking algorithm can be used to quantify an amount of gas captured by the devices according to frequency shift. Noise analysis is also conducted according to the embodiments, which shows that the microbeam devices have high stability against thermal noise. The microbeam devices are also suitable for the generation of binary sensing information for alarming, for example.

A μp based automation system for Raman and Rayleigh spectrometers

International Nuclear Information System (INIS)

Kesavamoorthy, R.; Arora, A.K.; Vasumathi, D.

1988-01-01

μp based data acquisition cum automation system for Raman and Rayleigh Spectrometers is described. The experiments require simultaneous acquisition of different digital data in two separate counters, their storage and rotation of grating through stepper motor in a repetitive cycle. Various modes of operation are selected through a function keyboard. The current status of the experiment is also displayed using 7 segment 12 element display unit. The input parameters are fed through a hexadecimal keyboard before the start of the experiment. The stored data can be send to a printer/terminal or to a PC through a serial port after the completion of the experiment. (author)

Fe-Ti-Cr-Oxides in Martian Meteorite EETA79001 Studied by Point-counting Procedure Using Raman Spectroscopy

Science.gov (United States)

Wang, Alian; Kuebler, Karla E.; Jolliff, Bradley L.; Haskin, Larry A.

2003-01-01

Fe-Ti-Cr-Oxide minerals contain much information about rock petrogenesis and alteration. Among the most important in the petrology of common intrusive and extrusive rocks are those of the FeO-TiO2-Cr2O3 compositional system chromite, ulv spinel-magnetite, and ilmenite-hematite. These minerals retain memories of oxygen fugacity. Their exsolution into companion mineral pairs give constraints on formation temperature and cooling rate. Laser Raman spectroscopy is anticipated to be a powerful technique for characterization of materials on the surface of Mars. A Mars Microbeam Raman Spectrometer (MMRS) is under development. It combines a micro sized laser beam and an automatic point-counting mechanism, and so can detect minor minerals or weak Raman-scattering phases such as Fe- Ti-Cr-oxides in mixtures (rocks & soils), and provide information on grain size and mineral mode. Most Fe-Ti-Cr-oxides produce weaker Raman signals than those from oxyanionic minerals, e.g. carbonates, sulfates, phosphates, and silicates, partly because most of them are intrinsically weaker Raman scatters, and partly because their dark colors limit the penetration depth of the excitation laser beam (visible wavelength) and of the Raman radiation produced. The purpose of this study is to show how well the Fe-Ti-Cr-oxides can be characterized by on-surface planetary exploration using Raman spectroscopy. We studied the basic Raman features of common examples of these minerals using well-characterized individual mineral grains. The knowledge gained was then used to study the Fe-Ti-Cr-oxides in Martian meteorite EETA79001, especially effects of compositional and structural variations on their Raman features.

Dynamics of Microbeams under Multi-Frequency Excitations

KAUST Repository

Ibrahim, Alwathiqbellah

2017-01-24

This paper presents an investigation of the dynamics of microbeams under multiple harmonic electrostatic excitation frequencies. First, the response of a cantilever microbeam to two alternating current (AC) source excitation is examined. We show by simulations the response of the microbeam at primary resonance (near the fundamental natural frequency) and at secondary resonances (near half, superharmonic, and twice, subharmonic, the fundamental natural frequency). A multimode Galerkin method combined with the Euler-Bernoulli beam equation, accounting for the nonlinear electrostatic force, has been used to develop a reduced order model. The response of the cantilever microbeam to three AC source excitation is also investigated and shown as a promising technique to enhance the bandwidth of resonators. Finally, an experimental study of a clamped-clamped microbeam is conducted, demonstrating the multi-frequency excitation resonances using two, three, and four AC sources.

Dynamics of Microbeams under Multi-Frequency Excitations

KAUST Repository

Ibrahim, Alwathiqbellah; Jaber, Nizar; Chandran, Akhil; Thirupathi, Maloth; Younis, Mohammad I.

2017-01-01

This paper presents an investigation of the dynamics of microbeams under multiple harmonic electrostatic excitation frequencies. First, the response of a cantilever microbeam to two alternating current (AC) source excitation is examined. We show by simulations the response of the microbeam at primary resonance (near the fundamental natural frequency) and at secondary resonances (near half, superharmonic, and twice, subharmonic, the fundamental natural frequency). A multimode Galerkin method combined with the Euler-Bernoulli beam equation, accounting for the nonlinear electrostatic force, has been used to develop a reduced order model. The response of the cantilever microbeam to three AC source excitation is also investigated and shown as a promising technique to enhance the bandwidth of resonators. Finally, an experimental study of a clamped-clamped microbeam is conducted, demonstrating the multi-frequency excitation resonances using two, three, and four AC sources.

Microbeam evolution: From single cell irradiation to preclinical studies

DEFF Research Database (Denmark)

Ghita, Mihaela; Fernandez-Palomo, Cristian; Fukunaga, Hisanori

2018-01-01

Purpose: This review follows the development of microbeam technology from the early days of single cell irradiations, to investigations of specific cellular mechanisms and to the development of new treatment modalities in vivo. A number of microbeam applications are discussed with a focus on prec...... to deliver radiotherapy using plane parallel microbeams, in Microbeam Radiotherapy (MRT)....

The Amsterdam proton microbeam

International Nuclear Information System (INIS)

Bos, A.J.J.

1984-01-01

The aim of the work presented in this thesis is to develop a microbeam setup such that small beam spot sizes can be produced routinely, and to investigate the capabilities of the setup for micro-PIXE analysis. The development and performance of the Amsterdam proton microbeam setup are described. The capabilities of the setup for micro-PIXE are shown with an investigation into the presence of trace elements in human hair. (Auth.)

Proceedings of 6th International Microbeam Workshop/12th L.H. Gray Workshop Microbeam Probes of Cellular Radiation Response

International Nuclear Information System (INIS)

Prise, Kevin M.

2004-01-01

The extended abstracts which are submitted here present a summary of the proceedings of the 6th International Workshop/12th LH Gray Workshop: Microbeam Probes of Cellular Radiation Response, held at St. Catherine's College, University of Oxford, UK on March, 29th-31st, 2003. In 1993 the 4th LH Gray Workshop entitled ''Microbeam Probes of Cellular Radiation Response'' was held at the Gray Cancer Institute in Northwood. This was organized by Prof BD Michael, Dr M. Folkard and Dr KM Prise and brought together 40 participants interested in developing and applying new microbeam technology to problems in radiation biology (1). The workshop was an undoubted success and has spawned a series of subsequent workshops every two years. In the past, these workshops have been highly successful in bringing together groups interested in developing and applying micro-irradiation techniques to the study of cell and tissue damage by ionizing radiations. Following the first microbeam workshop, there has been a rapid growth in the number of centres developing radiobiology microbeams, or planning to do so and there are currently 15-20 worldwide. Much of the recent research using microbeams has used them to study low-dose effects and ''non-targeted'' responses such bystander effects, genomic instability and adaptive responses. The goal of the 6th workshop was to build on our knowledge of the development of microbeam approaches and the application to radiation biology in the future with the meeting stretching over a 3 day period. Over 80 participants reviewed the current state of radiobiology microbeam research worldwide and reported on new technological developments both in the fields of physics and biology

Wide area scanning system and carbon microbeams at the external microbeam facility of the INFN LABEC laboratory in Florence

International Nuclear Information System (INIS)

Giuntini, L.; Massi, M.; Calusi, S.; Castelli, L.; Carraresi, L.; Fedi, M.E.; Gelli, N.; Liccioli, L.; Mandò, P.A.; Mazzinghi, A.; Palla, L.; Romano, F.P.

2015-01-01

Recently, developments have been made to the external scanning microbeam of INFN-LABEC laboratory in Florence. A new system for mechanical sample scanning was implemented. This system allows us to acquire large maps (up to 20 × 20 cm 2 ), of great interest in the Cultural Heritage field. In parallel, the possibility of using carbon microbeams for experiments, such as, for example, ion beam modification of materials and MeV Secondary Ion Mass Spectrometry, has been investigated. As a test application, Particle Induced X-ray Emission with carbon microbeams has been performed on a lapis lazuli stone. First results for both wide area imaging and external carbon microbeams are briefly reported

Genome-wide transcription responses to synchrotron microbeam radiotherapy.

Science.gov (United States)

Sprung, Carl N; Yang, Yuqing; Forrester, Helen B; Li, Jason; Zaitseva, Marina; Cann, Leonie; Restall, Tina; Anderson, Robin L; Crosbie, Jeffrey C; Rogers, Peter A W

2012-10-01

The majority of cancer patients achieve benefit from radiotherapy. A significant limitation of radiotherapy is its relatively low therapeutic index, defined as the maximum radiation dose that causes acceptable normal tissue damage to the minimum dose required to achieve tumor control. Recently, a new radiotherapy modality using synchrotron-generated X-ray microbeam radiotherapy has been demonstrated in animal models to ablate tumors with concurrent sparing of normal tissue. Very little work has been undertaken into the cellular and molecular mechanisms that differentiate microbeam radiotherapy from broad beam. The purpose of this study was to investigate and compare the whole genome transcriptional response of in vivo microbeam radiotherapy versus broad beam irradiated tumors. We hypothesized that gene expression changes after microbeam radiotherapy are different from those seen after broad beam. We found that in EMT6.5 tumors at 4-48 h postirradiation, microbeam radiotherapy differentially regulates a number of genes, including major histocompatibility complex (MHC) class II antigen gene family members, and other immunity-related genes including Ciita, Ifng, Cxcl1, Cxcl9, Indo and Ubd when compared to broad beam. Our findings demonstrate molecular differences in the tumor response to microbeam versus broad beam irradiation and these differences provide insight into the underlying mechanisms of microbeam radiotherapy and broad beam.

Wide area scanning system and carbon microbeams at the external microbeam facility of the INFN LABEC laboratory in Florence

Energy Technology Data Exchange (ETDEWEB)

Giuntini, L. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Massi, M. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Calusi, S. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Castelli, L. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Carraresi, L. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Fedi, M.E.; Gelli, N. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Liccioli, L.; Mandò, P.A.; Mazzinghi, A. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Palla, L. [INFN, Sezione di Pisa and Università di Pisa, Largo B. Pontecorvo 3, I-56127 Pisa (Italy); Romano, F.P. [Consiglio Nazionale delle Ricerche (CNR), Istituto per i Beni Archeologici e Monumentali (IBAM), Via Biblioteca, 4, 95124 Catania (Italy); Istituto Nazionale di Fisica Nucleare (INFN), LNS, Via S.Sofia 62, 95125 Catania (Italy); and others

2015-04-01

Recently, developments have been made to the external scanning microbeam of INFN-LABEC laboratory in Florence. A new system for mechanical sample scanning was implemented. This system allows us to acquire large maps (up to 20 × 20 cm{sup 2}), of great interest in the Cultural Heritage field. In parallel, the possibility of using carbon microbeams for experiments, such as, for example, ion beam modification of materials and MeV Secondary Ion Mass Spectrometry, has been investigated. As a test application, Particle Induced X-ray Emission with carbon microbeams has been performed on a lapis lazuli stone. First results for both wide area imaging and external carbon microbeams are briefly reported.

A horizontal multi-purpose microbeam system

Science.gov (United States)

Xu, Y.; Randers-Pehrson, G.; Marino, S. A.; Garty, G.; Harken, A.; Brenner, D. J.

2018-04-01

A horizontal multi-purpose microbeam system with a single electrostatic quadruplet focusing lens has been developed at the Columbia University Radiological Research Accelerator Facility (RARAF). It is coupled with the RARAF 5.5 MV Singleton accelerator (High Voltage Engineering Europa, the Netherlands) and provides micrometer-size beam for single cell irradiation experiments. It is also used as the primary beam for a neutron microbeam and microPIXE (particle induced x-ray emission) experiment because of its high particle fluence. The optimization of this microbeam has been investigated with ray tracing simulations and the beam spot size has been verified by different measurements.

Design and Calibration of a Raman Spectrometer for use in a Laser Spectroscopy Instrument Intended to Analyze Martian Surface and Atmospheric Characteristics for NASA

Science.gov (United States)

Lucas, John F.; Hornef, James

2016-01-01

This project's goal is the design of a Raman spectroscopy instrument to be utilized by NASA in an integrated spectroscopy strategy that will include Laser-Induced Breakdown Spectroscopy (LIBS) and Laser-Induced Florescence Spectroscopy (LIFS) for molecule and element identification on Mars Europa, and various asteroids. The instrument is to be down scaled from a dedicated rover mounted instrument into a compact unit with the same capabilities and accuracy as the larger instrument. The focus for this design is a spectrometer that utilizes Raman spectroscopy. The spectrometer has a calculated range of 218 nm wavelength spectrum with a resolution of 1.23 nm. To filter out the laser source wavelength of 532 nm the spectrometer design utilizes a 532 nm wavelength dichroic mirror and a 532 nm wavelength notch filter. The remaining scatter signal is concentrated by a 20 x microscopic objective through a 25-micron vertical slit into a 5mm diameter, 1cm focal length double concave focusing lens. The light is then diffracted by a 1600 Lines per Millimeter (L/mm) dual holographic transmission grating. This spectrum signal is captured by a 1-inch diameter double convex 3 cm focal length capture lens. An Intensified Charge Couple Device (ICCD) is placed within the initial focal cone of the capture lens and the Raman signal captured is to be analyzed through spectroscopy imaging software. This combination allows for accurate Raman spectroscopy to be achieved. The components for the spectrometer have been bench tested in a series of prototype developments based on theoretical calculations, alignment, and scaling strategies. The mounting platform is 2.5 cm wide by 8.8 cm long by 7 cm height. This platform has been tested and calibrated with various sources such as a neon light source and ruby crystal. This platform is intended to be enclosed in a ruggedized enclosure for mounting on a rover platform. The size and functionality of the Raman spectrometer allows for the rover to

Ion, X-ray, UV and Neutron Microbeam Systems for Cell Irradiation.

Science.gov (United States)

Bigelow, A W; Randers-Pehrson, G; Garty, G; Geard, C R; Xu, Y; Harken, A D; Johnson, G W; Brenner, D J

2010-08-08

The array of microbeam cell-irradiation systems, available to users at the Radiological Research Accelerator Facility (RARAF), Center for Radiological Research, Columbia University, is expanding. The HVE 5MV Singletron particle accelerator at the facility provides particles to two focused ion microbeam lines: the sub-micron microbeam II and the permanent magnetic microbeam (PMM). Both the electrostatic quadrupole lenses on the microbeam II system and the magnetic quadrupole lenses on the PMM system are arranged as compound lenses consisting of two quadrupole triplets with "Russian" symmetry. Also, the RARAF accelerator is a source for a proton-induced x-ray microbeam (undergoing testing) and is projected to supply protons to a neutron microbeam based on the (7)Li(p, n)(7)Be nuclear reaction (under development). Leveraging from the multiphoton microscope technology integrated within the microbeam II endstation, a UV microspot irradiator - based on multiphoton excitation - is available for facility users. Highlights from radiation-biology demonstrations on single living mammalian cells are included in this review of microbeam systems for cell irradiation at RARAF.

Raman Spectroscopy with simple optic components

International Nuclear Information System (INIS)

Mendoza, Mario; Cunya, Eduardo; Olivera, Paula

2014-01-01

Raman Spectroscopy is .a high resolution photonics technique that provides chemical and structural information of almost any material, organic or inorganic compound. In this report we describe the implementation of a system based on the principle of Raman scattering, developed to analyze solid samples. The spectrometer integrates an optical bench coupled to an optical fiber and a green laser source of 532 nm. The spectrometer was tested obtaining the Naphthalene and the Yellow 74 Pigment Raman patterns. (authors).

The new Sandia light ion microbeam

Energy Technology Data Exchange (ETDEWEB)

Vizkelethy, G., E-mail: gvizkel@sandia.gov [Sandia National Laboratories, P.O. Box 5800, MS 1056, Albuquerque, NM 87185 (United States); Doyle, B.L. [Sandia National Laboratories, P.O. Box 5800, MS 1056, Albuquerque, NM 87185 (United States); McDaniel, F.L. [Sandia National Laboratories, P.O. Box 5800, MS 1056, Albuquerque, NM 87185 (United States); University of North Texas, Denton, TX 76203 (United States)

2012-02-15

The Ion Beam Laboratory of Sandia National Laboratories (SNL) was recently relocated into a brand new building. The 6 MV High Voltage Engineering (HVE) tandem accelerator (hosting the heavy ion microbeam and several analytical beam lines) and the 350 kV HVE implanter with a nanobeam were moved to the new building. There were several new pieces of equipment acquired associated with the move, among them a new high brightness 3 MV Pelletron accelerator, a high resolution light ion microbeam, a nanoimplanter, and a transmission electron microscope (TEM) connected to the tandem accelerator. In this paper this new facility will be described, and initial results of the new microbeam will be presented.

Use of the product of mean intensity ratio (PMIR) technique for discriminant analysis of lycopene-rich vegetable juice using a portable NIR-excited Raman spectrometer.

Science.gov (United States)

Hara, Risa; Ishigaki, Mika; Kitahama, Yasutaka; Ozaki, Yukihiro; Genkawa, Takuma

2018-02-15

In this study, a lycopene-content-based discriminant analysis was performed using a portable near-infrared-excited Raman spectrometer. In the vegetable-juice Raman spectra, the peak intensity of the lycopene band increased with increasing lycopene concentration, but scattering decreased the repeatability of the peak intensity. Consequently, developing a lycopene-concentration regression model using peak intensity is not straightforward. Therefore, a new method known as the product of mean intensity ratio (PMIR) analysis was developed to rapidly identify lycopene-rich samples on-site. In the PMIR analysis, Raman spectra are measured with short exposure times, confirming only the peaks of carotenoids with high concentrations, and thus the lycopene concentrations of vegetable juice samples could be determined successfully. Exposure times of 20ms and 100ms could detect lycopene concentrations of ≥5mg/100g and ≥2mg/100g with 93.2% and 97.7% accuracy, respectively; thus, lycopene-content-based discriminant analysis using the PMIR and a portable Raman spectrometer is feasible. Copyright © 2017 Elsevier Ltd. All rights reserved.

High resolution 3D imaging of synchrotron generated microbeams

Energy Technology Data Exchange (ETDEWEB)

Gagliardi, Frank M., E-mail: frank.gagliardi@wbrc.org.au [Alfred Health Radiation Oncology, The Alfred, Melbourne, Victoria 3004, Australia and School of Medical Sciences, RMIT University, Bundoora, Victoria 3083 (Australia); Cornelius, Iwan [Imaging and Medical Beamline, Australian Synchrotron, Clayton, Victoria 3168, Australia and Centre for Medical Radiation Physics, University of Wollongong, Wollongong, New South Wales 2500 (Australia); Blencowe, Anton [Division of Health Sciences, School of Pharmacy and Medical Sciences, The University of South Australia, Adelaide, South Australia 5000, Australia and Division of Information Technology, Engineering and the Environment, Mawson Institute, University of South Australia, Mawson Lakes, South Australia 5095 (Australia); Franich, Rick D. [School of Applied Sciences and Health Innovations Research Institute, RMIT University, Melbourne, Victoria 3000 (Australia); Geso, Moshi [School of Medical Sciences, RMIT University, Bundoora, Victoria 3083 (Australia)

2015-12-15

Purpose: Microbeam radiation therapy (MRT) techniques are under investigation at synchrotrons worldwide. Favourable outcomes from animal and cell culture studies have proven the efficacy of MRT. The aim of MRT researchers currently is to progress to human clinical trials in the near future. The purpose of this study was to demonstrate the high resolution and 3D imaging of synchrotron generated microbeams in PRESAGE® dosimeters using laser fluorescence confocal microscopy. Methods: Water equivalent PRESAGE® dosimeters were fabricated and irradiated with microbeams on the Imaging and Medical Beamline at the Australian Synchrotron. Microbeam arrays comprised of microbeams 25–50 μm wide with 200 or 400 μm peak-to-peak spacing were delivered as single, cross-fire, multidirectional, and interspersed arrays. Imaging of the dosimeters was performed using a NIKON A1 laser fluorescence confocal microscope. Results: The spatial fractionation of the MRT beams was clearly visible in 2D and up to 9 mm in depth. Individual microbeams were easily resolved with the full width at half maximum of microbeams measured on images with resolutions of as low as 0.09 μm/pixel. Profiles obtained demonstrated the change of the peak-to-valley dose ratio for interspersed MRT microbeam arrays and subtle variations in the sample positioning by the sample stage goniometer were measured. Conclusions: Laser fluorescence confocal microscopy of MRT irradiated PRESAGE® dosimeters has been validated in this study as a high resolution imaging tool for the independent spatial and geometrical verification of MRT beam delivery.

High resolution 3D imaging of synchrotron generated microbeams

International Nuclear Information System (INIS)

Gagliardi, Frank M.; Cornelius, Iwan; Blencowe, Anton; Franich, Rick D.; Geso, Moshi

2015-01-01

Purpose: Microbeam radiation therapy (MRT) techniques are under investigation at synchrotrons worldwide. Favourable outcomes from animal and cell culture studies have proven the efficacy of MRT. The aim of MRT researchers currently is to progress to human clinical trials in the near future. The purpose of this study was to demonstrate the high resolution and 3D imaging of synchrotron generated microbeams in PRESAGE® dosimeters using laser fluorescence confocal microscopy. Methods: Water equivalent PRESAGE® dosimeters were fabricated and irradiated with microbeams on the Imaging and Medical Beamline at the Australian Synchrotron. Microbeam arrays comprised of microbeams 25–50 μm wide with 200 or 400 μm peak-to-peak spacing were delivered as single, cross-fire, multidirectional, and interspersed arrays. Imaging of the dosimeters was performed using a NIKON A1 laser fluorescence confocal microscope. Results: The spatial fractionation of the MRT beams was clearly visible in 2D and up to 9 mm in depth. Individual microbeams were easily resolved with the full width at half maximum of microbeams measured on images with resolutions of as low as 0.09 μm/pixel. Profiles obtained demonstrated the change of the peak-to-valley dose ratio for interspersed MRT microbeam arrays and subtle variations in the sample positioning by the sample stage goniometer were measured. Conclusions: Laser fluorescence confocal microscopy of MRT irradiated PRESAGE® dosimeters has been validated in this study as a high resolution imaging tool for the independent spatial and geometrical verification of MRT beam delivery

Scanning angle Raman spectroscopy: Investigation of Raman scatter enhancement techniques for chemical analysis

Energy Technology Data Exchange (ETDEWEB)

Meyer, Matthew W. [Iowa State Univ., Ames, IA (United States)

2013-01-01

This thesis outlines advancements in Raman scatter enhancement techniques by applying evanescent fields, standing-waves (waveguides) and surface enhancements to increase the generated mean square electric field, which is directly related to the intensity of Raman scattering. These techniques are accomplished by employing scanning angle Raman spectroscopy and surface enhanced Raman spectroscopy. A 1064 nm multichannel Raman spectrometer is discussed for chemical analysis of lignin. Extending dispersive multichannel Raman spectroscopy to 1064 nm reduces the fluorescence interference that can mask the weaker Raman scattering. Overall, these techniques help address the major obstacles in Raman spectroscopy for chemical analysis, which include the inherently weak Raman cross section and susceptibility to fluorescence interference.

7th International Workshop on Microbeam Probes of Cellular Radiation Response

Energy Technology Data Exchange (ETDEWEB)

Brenner, David J.

2009-07-21

The extended abstracts that follow present a summary of the Proceedings of the 7th International Workshop: Microbeam Probes of Cellular Radiation Response, held at Columbia University’s Kellogg Center in New York City on March 15–17, 2006. These International Workshops on Microbeam Probes of Cellular Radiation Response have been held regularly since 1993 (1–5). Since the first workshop, there has been a rapid growth (see Fig. 1) in the number of centers developing microbeams for radiobiological research, and worldwide there are currently about 30 microbeams in operation or under development. Single-cell/single-particle microbeam systems can deliver beams of different ionizing radiations with a spatial resolution of a few micrometers down to a few tenths of a micrometer. Microbeams can be used to addressquestions relating to the effects of low doses of radiation (a single radiation track traversing a cell or group of cells), to probe subcellular targets (e.g. nucleus or cytoplasm), and to address questions regarding the propagation of information about DNA damage (for example, the radiation-induced bystander effect). Much of the recent research using microbeams has been to study low-dose effects and ‘‘non-targeted’’ responses such as bystander effects, genomic instability and adaptive responses. This Workshop provided a forum to assess the current state of microbeam technology and current biological applications and to discuss future directions for development, both technological and biological. Over 100 participants reviewed the current state of microbeam research worldwide and reported on new technological developments in the fields of both physics and biology.

Raman Spectra from Pesticides on the Surface of Fruits

International Nuclear Information System (INIS)

Zhang, P X; Zhou Xiaofang; Cheng, Andrew Y S; Fang Yan

2006-01-01

Raman spectra of several vegetables and fruits were studied by micro-Raman spectrometer (514.5 nm) and Near-infrared Fourier Transform Raman spectrometer (FTRaman). It is shown that at 514.5 nm excitation, most of the spectra are from that of carotene with some very strong fluorescence in some cases. While at 1064 nm wavelength excitation, the spectra from the different samples demonstrate different characteristic Raman spectra without fluorescence. We discuss the spectroscopic difference by the two excitation wavelengths, and the application of Raman spectra for detection of pesticides left on the surface of vegetables and fruits. Raman spectra of fruits and pesticides were successfully recorded, and using the FT-Raman spectra the pesticides left on the surface of the fruits can be detected conveniently

Response of avian embryonic brain to spatially segmented x-ray microbeams.

Science.gov (United States)

Dilmanian, F A; Morris, G M; Le Duc, G; Huang, X; Ren, B; Bacarian, T; Allen, J C; Kalef-Ezra, J; Orion, I; Rosen, E M; Sandhu, T; Sathé, P; Wu, X Y; Zhong, Z; Shivaprasad, H L

2001-05-01

Duck embryo was studied as a model for assessing the effects of microbeam radiation therapy (MRT) on the human infant brain. Because of the high risk of radiation-induced disruption of the developmental process in the immature brain, conventional wide-beam radiotherapy of brain tumors is seldom carried out in infants under the age of three. Other types of treatment for pediatric brain tumors are frequently ineffective. Recent findings from studies in Grenoble on the brain of suckling rats indicate that MRT could be of benefit for the treatment of early childhood tumors. In our studies, duck embryos were irradiated at 3-4 days prior to hatching. Irradiation was carried out using a single exposure of synchrotron-generated X-rays, either in the form of parallel microplanar beams (microbeams), or as non-segmented broad beam. The individual microplanar beams had a width of 27 microm and height of 11 mm, and a center-to-center spacing of 100 microm. Doses to the exposed areas of embryo brain were 40, 80, 160 and 450 Gy (in-slice dose) for the microbeam, and 6, 12 and 18 Gy for the broad beam. The biological end point employed in the study was ataxia. This neurological symptom of radiation damage to the brain developed within 75 days of hatching. Histopathological analysis of brain tissue did not reveal any radiation induced lesions for microbeam doses of 40-160 Gy (in-slice), although some incidences of ataxia were observed in that dose group. However, severe brain lesions did occur in animals in the 450 Gy microbeam dose groups, and mild lesions in the 18 Gy broad beam dose group. These results indicate that embryonic duck brain has an appreciably higher tolerance to the microbeam modality, as compared to the broad beam modality. When the microbeam dose was normalized to the full volume of the irradiated tissue. i.e., the dose averaged over microbeams and the space between the microbeams, brain tolerance was estimated to be about three times higher to microbeam

High energy ion hit technique to local area using microbeam

Energy Technology Data Exchange (ETDEWEB)

Tanaka, Ryuichi; Kamiya, Tomihiro; Suda, Tamotsu; Sakai, Takuro; Hirao, Toshio; Kobayashi, Yasuhiko; Watanabe, Hiroshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

1997-03-01

Single energetic ion hit technique has been developed as an application of ion microbeam technique, in order to study the effect of local damage or injury to materials and living organisms. The overall performance is basically defined by those of separate techniques: microbeam formation, microbeam positioning, single ion detection, detection signal processing, hit timing control, and hit verification. Recent progress on the developments of these techniques at JAERI-TIARA facility are reviewed. (author)

Improving Spectral Results Using Row-by-Row Fourier Transform of Spatial Heterodyne Raman Spectrometer Interferogram.

Science.gov (United States)

Barnett, Patrick D; Strange, K Alicia; Angel, S Michael

2017-06-01

This work describes a method of applying the Fourier transform to the two-dimensional Fizeau fringe patterns generated by the spatial heterodyne Raman spectrometer (SHRS), a dispersive interferometer, to correct the effects of certain types of optical alignment errors. In the SHRS, certain types of optical misalignments result in wavelength-dependent and wavelength-independent rotations of the fringe pattern on the detector. We describe here a simple correction technique that can be used in post-processing, by applying the Fourier transform in a row-by-row manner. This allows the user to be more forgiving of fringe alignment and allows for a reduction in the mechanical complexity of the SHRS.

Synchrotron microbeam radiation therapy for rat brain tumor palliation-influence of the microbeam width at constant valley dose

International Nuclear Information System (INIS)

Serduc, Raphael; Fonta, Caroline; Renaud, Luc; Bouchet, Audrey; Braeuer-Krisch, Elke; Sarun, Sukhena; Bravin, Alberto; Le Duc, Geraldine; Laissue, Jean A; Spiga, Jenny; Boutonnat, Jean; Siegbahn, Erik Albert; Esteve, Francois

2009-01-01

To analyze the effects of the microbeam width (25, 50 and 75 μm) on the survival of 9L gliosarcoma tumor-bearing rats and on toxicity in normal tissues in normal rats after microbeam radiation therapy (MRT), 9L gliosarcomas implanted in rat brains, as well as in normal rat brains, were irradiated in the MRT mode. Three configurations (MRT25, MRT50, MRT75), each using two orthogonally intersecting arrays of either 25, 50 or 75 μm wide microbeams, all spaced 211 μm on center, were tested. For each configuration, peak entrance doses of 860, 480 and 320 Gy, respectively, were calculated to produce an identical valley dose of 18 Gy per individual array at the center of the tumor. Two, 7 and 14 days after radiation treatment, 42 rats were killed to evaluate histopathologically the extent of tumor necrosis, and the presence of proliferating tumors cells and tumor vessels. The median survival times of the normal rats were 4.5, 68 and 48 days for MRT25, 50 and 75, respectively. The combination of the highest entrance doses (860 Gy per array) with 25 μm wide beams (MRT25) resulted in a cumulative valley dose of 36 Gy and was excessively toxic, as it led to early death of all normal rats and of ∼50% of tumor-bearing rats. The short survival times, particularly of rats in the MRT25 group, restricted adequate observance of the therapeutic effect of the method on tumor-bearing rats. However, microbeams of 50 μm width led to the best median survival time after 9L gliosarcoma MRT treatment and appeared as the better compromise between tumor control and normal brain toxicity compared with 75 μm or 25 μm widths when used with a 211 μm on-center distance. Despite very high radiation doses, the tumors were not sterilized; viable proliferating tumor cells remained present at the tumor margin. This study shows that microbeam width and peak entrance doses strongly influence tumor responses and normal brain toxicity, even if valley doses are kept constant in all groups. The use

Synchrotron microbeam radiation therapy for rat brain tumor palliation-influence of the microbeam width at constant valley dose

Energy Technology Data Exchange (ETDEWEB)

Serduc, Raphael; Fonta, Caroline; Renaud, Luc [Universite de Toulouse, UPS, Centre de Recherche Cerveau et Cognition (France); Bouchet, Audrey; Braeuer-Krisch, Elke; Sarun, Sukhena; Bravin, Alberto; Le Duc, Geraldine [European Synchrotron Radiation Facility, F38043 Grenoble (France); Laissue, Jean A [Institute of Pathology, University of Bern (Switzerland); Spiga, Jenny [Department of Physics, University of Cagliari, s.p. Monserrato-Sestu, Monserrato (Canada) 09042 (Italy); Boutonnat, Jean [TIMC lab, UMR CNRS 5525, Univ Joseph Fourier, CHU, Grenoble (France); Siegbahn, Erik Albert [Department of Medical Physics, Karolinska Universitetssjukhuset, 17176 Stockholm (Sweden); Esteve, Francois [INSERM U836, Equipe 6, Institut des Neurosciences de Grenoble, 38043 Grenoble Cedex (France)], E-mail: raph.serduc@gmail.com

2009-11-07

To analyze the effects of the microbeam width (25, 50 and 75 {mu}m) on the survival of 9L gliosarcoma tumor-bearing rats and on toxicity in normal tissues in normal rats after microbeam radiation therapy (MRT), 9L gliosarcomas implanted in rat brains, as well as in normal rat brains, were irradiated in the MRT mode. Three configurations (MRT25, MRT50, MRT75), each using two orthogonally intersecting arrays of either 25, 50 or 75 {mu}m wide microbeams, all spaced 211 {mu}m on center, were tested. For each configuration, peak entrance doses of 860, 480 and 320 Gy, respectively, were calculated to produce an identical valley dose of 18 Gy per individual array at the center of the tumor. Two, 7 and 14 days after radiation treatment, 42 rats were killed to evaluate histopathologically the extent of tumor necrosis, and the presence of proliferating tumors cells and tumor vessels. The median survival times of the normal rats were 4.5, 68 and 48 days for MRT25, 50 and 75, respectively. The combination of the highest entrance doses (860 Gy per array) with 25 {mu}m wide beams (MRT25) resulted in a cumulative valley dose of 36 Gy and was excessively toxic, as it led to early death of all normal rats and of {approx}50% of tumor-bearing rats. The short survival times, particularly of rats in the MRT25 group, restricted adequate observance of the therapeutic effect of the method on tumor-bearing rats. However, microbeams of 50 {mu}m width led to the best median survival time after 9L gliosarcoma MRT treatment and appeared as the better compromise between tumor control and normal brain toxicity compared with 75 {mu}m or 25 {mu}m widths when used with a 211 {mu}m on-center distance. Despite very high radiation doses, the tumors were not sterilized; viable proliferating tumor cells remained present at the tumor margin. This study shows that microbeam width and peak entrance doses strongly influence tumor responses and normal brain toxicity, even if valley doses are kept constant in

Techniques and multi-disciplinary applications of ion microbeam

International Nuclear Information System (INIS)

Du Guanghua

2012-01-01

Beam of MeV ions form particle accelerators can be confined by collimators or focused by electrical/magnetic quadruples into micrometer size, and this microbeam can be used to obtain spatial information or radiation effect in solids and biological samples. This paper reviews the technical developments and the multi-disciplinary applications of microbeam, including ion beam analysis, single event effect in semiconductor devices, proton beam writing and cellular response to targeted particle irradiations. Finally, the high-energy heavy-ion microbeam facility at the Institute of Modern Physics of Chinese Academy of Sciences is introduced, which has successfully focused 1 GeV Carbon ions into a beam spot of 1 μm × 2 μm in air. (authors)

Conceptual design for real time monitoring of electron microbeam

International Nuclear Information System (INIS)

Kim, Ji Seok; Kim, Hyun Ki; Jang, Mee; Choi, Chang Woon; Sun, Gwang Min; Lee, Jai Ki

2008-01-01

It is recognized that the microbeam is powerful system to understand the interaction of ionizing radiation with cells. Especially, electron microbeam system is useful to investigate the effect of low-LET radiation for cells. Electron microbeam has been developed in KIRAMS. It can irradiate the small volume in cell level by collimator and electromagnetic field and give local dose to individual cell by controlling the number of electrons. When the electron microbeam irradiates the individual cell, however, there is a possibility to change the current and intended trajectory of electron beam. Because this possibility introduces the uncertainty of dose, it is necessary to monitor the trajectory and current of electron beam. This study deals with development of real time monitoring device to confirm beam quality and to control if necessary during experiment. Consequently we designed dual monitoring device to solve various factors. And we optimize the design by simulation. (author)

Attempts of local irradiation of cells by microbeam. From ultraviolet to heavy particles

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, Yasuhiko [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

2002-03-01

This review describes the history of attempts of local irradiation of cells by microbeam and present status of the study. Local irradiation of cells was attempted as early as in 1912 with use of short {alpha}-particle range and of focused UV beams. After the war, laser microbeams were then developed for microsurgery in embryology. In addition, microbeams of electron generated from the gun and of X-ray collimated were developed. In 1950s, the electron microbeam was generated from Van de Graaff accelerator in Chicago University and proton, deuteron and He-ion microbeams from the cyclotron, in BNL. In 1980s, Gesellschaft fuer Schwerionenforshung (Germany) used heavy ion microbeams from C to U generated from the linear accelerator and PNL, proton to {sup 4}He-ion microbeams from the tandem-electrostatic accelerator. At present in 2002, the equipments for microbeam for cell irradiation are the Van de Graaff accelerators in Gray Cancer Institute (England) and in Columbia University, and the cyclotron in TIARA in Japan. The purpose of the study in TIARA is to develop a system to generate heavy particle microbeams for cell irradiation for analysis of the biological effect of ultra-low fluence, high LET heavy particles like the galactic cosmic ray. Recently, the CHO-KI cell nucleus is irradiated by {sup 40}Ar and {sup 20}Ne ions. (K.H.)

Attempts of local irradiation of cells by microbeam. From ultraviolet to heavy particles

International Nuclear Information System (INIS)

Kobayashi, Yasuhiko

2002-01-01

This review describes the history of attempts of local irradiation of cells by microbeam and present status of the study. Local irradiation of cells was attempted as early as in 1912 with use of short α-particle range and of focused UV beams. After the war, laser microbeams were then developed for microsurgery in embryology. In addition, microbeams of electron generated from the gun and of X-ray collimated were developed. In 1950s, the electron microbeam was generated from Van de Graaff accelerator in Chicago University and proton, deuteron and He-ion microbeams from the cyclotron, in BNL. In 1980s, Gesellschaft fuer Schwerionenforshung (Germany) used heavy ion microbeams from C to U generated from the linear accelerator and PNL, proton to 4 He-ion microbeams from the tandem-electrostatic accelerator. At present in 2002, the equipments for microbeam for cell irradiation are the Van de Graaff accelerators in Gray Cancer Institute (England) and in Columbia University, and the cyclotron in TIARA in Japan. The purpose of the study in TIARA is to develop a system to generate heavy particle microbeams for cell irradiation for analysis of the biological effect of ultra-low fluence, high LET heavy particles like the galactic cosmic ray. Recently, the CHO-KI cell nucleus is irradiated by 40 Ar and 20 Ne ions. (K.H.)

Proton microbeam irradiation effects on PtBA polymer

Indian Academy of Sciences (India)

Microbeam irradiation effects on poly-tert-butyl-acrylate (PtBA) polymer using 2.0 MeV proton microbeam are reported. Preliminary results on pattern formation on PtBA are carried out as a function of fluence. After writing the pattern, a thin layer of Ge is deposited. Distribution of Ge in pristine and ion beam patterned surface ...

Confocal Raman Microscopy

CERN Document Server

Dieing, Thomas; Toporski, Jan

2011-01-01

Confocal Raman Microscopy is a relatively new technique that allows chemical imaging without specific sample preparation. By integrating a sensitive Raman spectrometer within a state-of-the-art microscope, Raman microscopy with a spatial resolution down to 200nm laterally and 500nm vertically can be achieved using visible light excitation. Recent developments in detector and computer technology as well as optimized instrument design have reduced integration times of Raman spectra by orders of magnitude, so that complete images consisting of tens of thousands of Raman spectra can be acquired in seconds or minutes rather than hours, which used to be standard just one decade ago. The purpose of this book is to provide the reader a comprehensive overview of the rapidly developing field of Confocal Raman Microscopy and its applications.

Nonlinear analysis of thermally and electrically actuated functionally graded material microbeam.

Science.gov (United States)

Li, Yingli; Meguid, S A; Fu, Yiming; Xu, Daolin

2014-02-08

In this paper, we provide a unified and self-consistent treatment of a functionally graded material (FGM) microbeam with varying thermal conductivity subjected to non-uniform or uniform temperature field. Specifically, it is our objective to determine the effect of the microscopic size of the beam, the electrostatic gap, the temperature field and material property on the pull-in voltage of the microbeam under different boundary conditions. The non-uniform temperature field is obtained by integrating the steady-state heat conduction equation. The governing equations account for the microbeam size by introducing an internal material length-scale parameter that is based on the modified couple stress theory. Furthermore, it takes into account Casimir and van der Waals forces, and the associated electrostatic force with the first-order fringing field effects. The resulting nonlinear differential equations were converted to a coupled system of algebraic equations using the differential quadrature method. The outcome of our work shows the dramatic effect and dependence of the pull-in voltage of the FGM microbeam upon the temperature field, its gradient for a given boundary condition. Specifically, both uniform and non-uniform thermal loading can actuate the FGM microbeam even without an applied voltage. Our work also reveals that the non-uniform temperature field is more effective than the uniform temperature field in actuating a FGM cantilever-type microbeam. For the clamped-clamped case, care must be taken to account for the effective use of thermal loading in the design of microbeams. It is also observed that uniform thermal loading will lead to a reduction in the pull-in voltage of a FGM microbeam for all the three boundary conditions considered.

Ultrafast stimulated Raman spectroscopy in the near-infrared region

International Nuclear Information System (INIS)

Takaya, Tomohisa

2016-01-01

A number of electronic transitions in the near-infrared wavelength region are associated with migration or delocalization of electrons in large molecules or molecular systems. Time-resolved near-infrared Raman spectroscopy will be a powerful tool for investigating the structural dynamic of samples with delocalized electrons. However, the sensitivity of near-infrared spontaneous Raman spectrometers is significantly low due to an extremely small probability of Raman scattering and a low sensitivity of near-infrared detectors. Nonlinear Raman spectroscopy is one of the techniques that can overcome the sensitivity problems and enable us to obtain time-resolved Raman spectra in resonance with near-IR transitions. In this article, the author introduces recent progress of ultrafast time-resolved near-infrared stimulated Raman spectroscopy. Optical setup, spectral and temporal resolution, and applications of the spectrometer are described. (author)

How to improve a critical performance for an ExoMars 2020 Scientific Instrument (RLS). Raman Laser Spectrometer Signal to Noise Ratio (SNR) Optimization

Science.gov (United States)

Canora, C. P.; Moral, A. G.; Rull, F.; Maurice, S.; Hutchinson, I.; Ramos, G.; López-Reyes, G.; Belenguer, T.; Canchal, R.; Prieto, J. A. R.; Rodriguez, P.; Santamaria, P.; Berrocal, A.; Colombo, M.; Gallago, P.; Seoane, L.; Quintana, C.; Ibarmia, S.; Zafra, J.; Saiz, J.; Santiago, A.; Marin, A.; Gordillo, C.; Escribano, D.; Sanz-Palominoa, M.

2017-09-01

The Raman Laser Spectrometer (RLS) is one of the Pasteur Payload instruments, within the ESA's Aurora Exploration Programme, ExoMars mission. Raman spectroscopy is based on the analysis of spectral fingerprints due to the inelastic scattering of light when interacting with matter. RLS is composed by Units: SPU (Spectrometer Unit), iOH (Internal Optical Head), and ICEU (Instrument Control and Excitation Unit) and the harnesses (EH and OH). The iOH focuses the excitation laser on the samples and collects the Raman emission from the sample via SPU (CCD) and the video data (analog) is received, digitalizing it and transmiting it to the processor module (ICEU). The main sources of noise arise from the sample, the background, and the instrument (Laser, CCD, focuss, acquisition parameters, operation control). In this last case the sources are mainly perturbations from the optics, dark signal and readout noise. Also flicker noise arising from laser emission fluctuations can be considered as instrument noise. In order to evaluate the SNR of a Raman instrument in a practical manner it is useful to perform end-to-end measurements on given standards samples. These measurements have to be compared with radiometric simulations using Raman efficiency values from literature and taking into account the different instrumental contributions to the SNR. The RLS EQM instrument performances results and its functionalities have been demonstrated in accordance with the science expectations. The Instrument obtained SNR performances in the RLS EQM will be compared experimentally and via analysis, with the Instrument Radiometric Model tool. The characterization process for SNR optimization is still on going. The operational parameters and RLS algorithms (fluorescence removal and acquisition parameters estimation) will be improved in future models (EQM-2) until FM Model delivery.

Raman and Photoluminescence Spectroscopy in Mineral Identification

Science.gov (United States)

Kuehn, J. W.

2014-06-01

Raman spectroscopy is particularly useful for rapid identification of minerals and gemstones. Raman spectrometers also allow PL studies for authentication of samples and geological provenance, diamond type screening and detection of HPHT treatments.

Mixture analysis with laser raman spctroscopy

International Nuclear Information System (INIS)

Kim, M.S.; Bark, G.M.

1981-01-01

Trace amount of methyl orange was determined in colored medium by resonance Raman spectrometry. Without major modification of a commercial laser Raman spectrometer, the resonance Raman active molecule could be determined satisfactorily in 10sup(-5)M range when the background fluorescence was more than 20 times stronger than the signal. Use of fluorescence quenching agent was found helpful to improve the Raman signal. Suggestions for the improvement of analytical method is presented. (Author)

MOSFET dosimetry of the radiation therapy microbeams at the European synchrotron radiation facility

International Nuclear Information System (INIS)

Rozenfeld, A.; Lerch, M.

2002-01-01

Full text: We have developed an innovative on-line MOSFET readout system for use in the quality assurance of radiation treatment beams. Recently the system has found application in areas where excellent spatial resolution is also a requirement in the quality assurance process, for example IMRT, and microbeam radiation therapy. The excellent spatial resolution is achieved by using a quadruple RADFET TM chip in 'edge on' mode. In developing this approach we have found that the system can be utilised to determine any error in the beam profile measurements due to misalignment of RADFET with respect to the radiation beam or microbeam. Using this approach will ensure that the excellent spatial resolution of the RADFET used in 'edge-on' mode is fully utilised. In this work we report on dosimetry measurements performed at the microbeam radiation therapy beamline located at the European Synchrotron Radiation Facility. The synchrotron planar array microbeam with size 10-30 μm and pitch ∼200 μm has found an important application in microbeam radiation therapy (MRT) of brain tumours in infants for whom other kinds of radiotherapy are inadequate and/or unsafe. The radiation damage from an array of parallel microbeams correlates strongly with the range of peak-valley dose ratios (PVDR), ie, the range of the ratio of the absorbed dose to tissue directly in line with the mid-plane of the microbeam to that in the mid-plane between adjacent microbeams. Novel physical dosimetry of the microbeams using the online MOSFET reader system will be presented. Comparison of the experimental results with both GaF film measurements and Monte Carlo computer-simulated dosimetry are described here for selected points in the peak and valley regions of a microbeam-irradiated tissue phantom

Heavy Ion Microbeam- and Broadbeam-Induced Current Transients in SiGe HBTs

Science.gov (United States)

Pellish, Jonathan A.; Reed, R. A.; McMorrow, D.; Vizkelethy, G.; Ferlet-Cavrois, V.; Baggio, J.; Duhamel, O.; Moen, K. A.; Phillips, S. D.; Diestelhorst, R. M.;

Dynamic Characteristics of Electrostatically Actuated Microbeams with Slant Crack

Directory of Open Access Journals (Sweden)

Han Zhou

2015-01-01

Full Text Available An improved model of the slant crack on a microbeam is presented. Based on fracture mechanics, the rotation coefficient for the slant crack is derived as a massless rotational spring accounting for the additional stress intensity factors generated by the orientation of the crack compared to the transverse crack. Comparisons between microbeams with a slant crack of different geometry parameters (slant angle, depth ratio, and crack position are investigated with regard to the dynamic mechanical behaviors and nonlinear response. By presenting a mathematical modeling, the effects of the slant crack and the electric actuation of an electrostatically actuated fixed-fixed microbeam on the dynamic characteristics are examined in detail. It is shown that the crack position has more significant influence on the pull-in voltage value than the slant angle or the depth ratio. Approaching the slant crack to the fixed end or enlarging the external incentives amplifies the nonlinearity of the microbeam system, while the effects of depth ratio and slant angle are dependent on the crack position. The resonance frequency and the resonance amplitude are affected as well.

A Molecularly Imprinted Polymer (MIP)-Coated Microbeam MEMS Sensor for Chemical Detection

Science.gov (United States)

2015-09-01

ARL-RP-0536 ● SEP 2015 US Army Research Laboratory A Molecularly Imprinted Polymer (MIP)- Coated Microbeam MEMS Sensor for...ARL-RP-0536 ● SEP 2015 US Army Research Laboratory A Molecularly Imprinted Polymer (MIP)- Coated Microbeam MEMS Sensor for Chemical...TITLE AND SUBTITLE A Molecularly Imprinted Polymer (MIP)-Coated Microbeam MEMS Sensor for Chemical Detection 5a. CONTRACT NUMBER 5b. GRANT NUMBER

Consequences of cytoplasmic irradiation. Studies from microbeam

International Nuclear Information System (INIS)

Zhou, Hongning; Hong, Mei; Chai, Yunfei; Hei, Tom K.

2009-01-01

The prevailing dogma for radiation biology is that genotoxic effects of ionizing radiation such as mutations and carcinogenesis are attributed mainly to direct damage to the nucleus. However, with the development of microbeam that can target precise positions inside the cells, accumulating evidences have shown that energy deposit by radiation in nuclear DNA is not required to trigger the damage, extra-nuclear or extra-cellular radiation could induce the similar biological effects as well. This review will summarize the biological responses after cytoplasm irradiated by microbeam, and the possible mechanisms involved in cytoplasmic irradiation. (author)

Microbeam facility at NIRS

International Nuclear Information System (INIS)

Sato, Yukio; Yamaguchi, Hiroshi

2000-01-01

Radiation biophysics or microdosimetry has suggested radiation effect mechanism. Full understanding of it has not yet been obtained. There are vast variety of events in physical, chemical and biological processes from at the time of irradiation to biological endpoints. Analysis of RBE-LET relation for biological endpoints like survival, mutation and transformation in cultured mammalian cells is still the leading subject to study the physical processes. The biological and repair processes have been studied phenomenologically through dose rate effect or fractionation experiment. Human genome project has accelerated biological sciences as a whole taking methodology of the molecular biology, where the mechanism is explained by molecules involved. We have thus to know entity and its (biological) function in every single process. Molecular biological approach in radiation biology has started and revealed several proteins being involved in the repair processes. Quantitative relation between phenomenological data like cell survivals and molecular processes, however, has been little known yet. A promising approach to fill this gap should be the study by microbeam, which enables us to see, for example, a deletion in chromosomal level by a single particle traverse of cell nucleus and may suggest possible molecular processes. Under this motivation we started feasibility study on installation of a microbeam port in our Tandem accelerator (5.1 MeV 4 He 2+ ). We have planned to adopt a lens focusing and a scanning system developed (by the Oxford microbeam Ltd) for the existing micro PIXE system in NIRS, which has basically achieved irradiation to a cell within a position resolution of 2 micrometer. There are two practical requirements, i.e. precise positioning and faster irradiation. These are described including research subjects planned. (author)

Light ion microbeam analysis / processing system and its improvement

International Nuclear Information System (INIS)

Koka, Masashi; Ishii, Yasuyuki; Yamada, Naoto; Ohkubo, Takeru; Kamiya, Tomihiro; Satoh, Takahiro; Kada, Wataru; Kitamura, Akane; Iwata, Yoshihiro

2016-03-01

A MeV-class light ion microbeam system has been developed for micro-analysis and micro-fabrication with high spatial resolution at 3-MV single-ended accelerator in Takasaki Ion Accelerators for Advanced Radiation Application of Takasaki Advanced Radiation Research Institute, Sector of Nuclear Science Research, Japan Atomic Energy Agency. This report describes the technical improvements for the main apparatus (the accelerator, beam-transport lines, and microbeam system), and auxiliary equipments/ parts for ion beam applications such as Particle Induced X-ray/Gamma-ray Emission (PIXE/PIGE) analysis, 3-D element distribution analysis using PIXE Computed Tomography (CT), Ion Beam Induced Luminescence (IBIL) analysis, and Proton Beam Writing with the microbeam scanning, with functional outline of these apparatus and equipments/parts. (author)

Picosecond laser fabricated Ag, Au and Ag-Au nanoparticles for detecting ammonium perchlorate using a portable Raman spectrometer

Science.gov (United States)

Byram, Chandu; Moram, Sree Sathya Bharathi; Soma, Venugopal Rao

2018-04-01

In this paper, we present the results from fabrication studies of Ag, Au, and Ag-Au alloy nanoparticles (NPs) using picosecond laser ablation technique in the presence of liquid media. The alloy formation in the NPs was confirmed from UV-Visible measurements. The shape and crystallinity of NPs were investigated by using high resolution transmission electron microscopy (HRTEM), selected area diffraction pattern (SAED) and energy dispersive spectroscopy (EDS). The SERS effect of fabricated NPs was tested with methylene blue and an explosive molecule (ammonium perchlorate) using a portable Raman spectrometer and achieved EFs of ˜106.

Improvement of the Energy Stability of the Single Ion Microbeam

International Nuclear Information System (INIS)

Zhan Furu; Qi Xuehong; Xu Mingliang; Chen Lianyun; Yu Zengliang

2008-01-01

Energy instability strongly affects the state and the beam size of the single ion microbeam. A facility based on the Generating Voltmeter was developed to improve the energy stability of the CAS-LIBB (Chinese Academy of Sciences, key laboratory of ion beam bioengineering) single ion microbeam. This paper presents the analysis of the energy instability of the single ion microbeam. A simplified theoretical model is set up to calculate the relationship between the energy instability and the beam spot size. By using this technique, the energy instability is adjusted to about 1%. Stable run-time is over 6 hours. The radius of the single ion beam is reduced by 10% compared to the previous one.

Design of the IMP microbeam irradiation system for 100 MeV/u heavy ions

International Nuclear Information System (INIS)

Sheng Lina; Song Mingtao; Zhang Xiaoqi; Yang Xiaotian; Gao Daqing; He Yuan; Zhang Bin; Liu Jie; Sun Youmei; Dang Bingrong; Lwenjian; Su Hong; Man Kaidi; Guo Yizhen; Wang Zhiguang; Zhan Wenlong

2009-01-01

A state-of-the-art high energy heavy ion microbeam irradiation system is constructed at the Institute of Modern Physics of the Chinese Academy of Sciences. This microbeam system operates in both full current intensity mode and single ion mode. It delivers a predefined number of ions to pre-selected targets for research in biology and material science. The characteristic of this microbeam system is high energy and vertical irradiation. A quadrupole focusing system, in combination with a series of slits, has been designed to optimize the spatial resolution. A symmetrically achromatic system leads the beam downwards and serves simultaneously as an energy analyzer. A high gradient quadrupole triplet finally focuses a C 6+ ion beam to 1 μm in the vacuum chamber within the energy range from 10 MeV/u to 100 MeV/u. In this paper, the IMP microbeam system is described in detail. A systematic investigation of the ion beam optics of this microbeam system is presented together with the associated aberrations. Comparison is made between the IMP microbeam system and the other existing systems to further discuss the performance of this microbeam. Then the optimized initial beam parameters are given for high resolution and high hitting efficiency. At last, the experiment platform is briefly introduced. (authors)

Compact Solid-State 213 nm Laser Enables Standoff Deep Ultraviolet Raman Spectrometer: Measurements of Nitrate Photochemistry.

Science.gov (United States)

Bykov, Sergei V; Mao, Michael; Gares, Katie L; Asher, Sanford A

2015-08-01

We describe a new compact acousto-optically Q-switched diode-pumped solid-state (DPSS) intracavity frequency-tripled neodymium-doped yttrium vanadate laser capable of producing ~100 mW of 213 nm power quasi-continuous wave as 15 ns pulses at a 30 kHz repetition rate. We use this new laser in a prototype of a deep ultraviolet (UV) Raman standoff spectrometer. We use a novel high-throughput, high-resolution Echelle Raman spectrograph. We measure the deep UV resonance Raman (UVRR) spectra of solid and solution sodium nitrate (NaNO3) and ammonium nitrate (NH4NO3) at a standoff distance of ~2.2 m. For this 2.2 m standoff distance and a 1 min spectral accumulation time, where we only monitor the symmetric stretching band, we find a solid state NaNO3 detection limit of ~100 μg/cm(2). We easily detect ~20 μM nitrate water solutions in 1 cm path length cells. As expected, the aqueous solutions UVRR spectra of NaNO3 and NH4NO3 are similar, showing selective resonance enhancement of the nitrate (NO3(-)) vibrations. The aqueous solution photochemistry is also similar, showing facile conversion of NO3(-) to nitrite (NO2(-)). In contrast, the observed UVRR spectra of NaNO3 and NH4NO3 powders significantly differ, because their solid-state photochemistries differ. Whereas solid NaNO3 photoconverts with a very low quantum yield to NaNO2, the NH4NO3 degrades with an apparent quantum yield of ~0.2 to gaseous species.

Vibration Characteristics of Piezoelectric Microbeams Based on the Modified Couple Stress Theory

Directory of Open Access Journals (Sweden)

R. Ansari

2014-01-01

Full Text Available The vibration behavior of piezoelectric microbeams is studied on the basis of the modified couple stress theory. The governing equations of motion and boundary conditions for the Euler-Bernoulli and Timoshenko beam models are derived using Hamilton’s principle. By the exact solution of the governing equations, an expression for natural frequencies of microbeams with simply supported boundary conditions is obtained. Numerical results for both beam models are presented and the effects of piezoelectricity and length scale parameter are illustrated. It is found that the influences of piezoelectricity and size effects are more prominent when the length of microbeams decreases. A comparison between two beam models also reveals that the Euler-Bernoulli beam model tends to overestimate the natural frequencies of microbeams as compared to its Timoshenko counterpart.

Development of a TOF SIMS setup at the Zagreb heavy ion microbeam facility

Science.gov (United States)

Tadić, Tonči; Bogdanović Radović, Iva; Siketić, Zdravko; Cosic, Donny Domagoj; Skukan, Natko; Jakšić, Milko; Matsuo, Jiro

2014-08-01

We describe a new Time-of-flight Secondary Ion Mass Spectrometry (TOF SIMS) setup for MeV SIMS application, which is constructed and installed at the heavy ion microbeam facility at the Ruđer Bošković Institute in Zagreb. The TOF-SIMS setup is developed for high sensitivity molecular imaging using a heavy ion microbeam that focuses ion beams (from C to I) with sub-micron resolution. Dedicated pulse processing electronics for MeV SIMS application have been developed, enabling microbeam-scanning control, incoming ion microbeam pulsing and molecular mapping. The first results showing measured MeV SIMS spectra as well as molecular maps for samples of interest are presented and discussed.

Development of a TOF SIMS setup at the Zagreb heavy ion microbeam facility

International Nuclear Information System (INIS)

Tadić, Tonči; Bogdanović Radović, Iva; Siketić, Zdravko; Cosic, Donny Domagoj; Skukan, Natko; Jakšić, Milko; Matsuo, Jiro

2014-01-01

We describe a new Time-of-flight Secondary Ion Mass Spectrometry (TOF SIMS) setup for MeV SIMS application, which is constructed and installed at the heavy ion microbeam facility at the Ruđer Bošković Institute in Zagreb. The TOF-SIMS setup is developed for high sensitivity molecular imaging using a heavy ion microbeam that focuses ion beams (from C to I) with sub-micron resolution. Dedicated pulse processing electronics for MeV SIMS application have been developed, enabling microbeam-scanning control, incoming ion microbeam pulsing and molecular mapping. The first results showing measured MeV SIMS spectra as well as molecular maps for samples of interest are presented and discussed

Alignment of dipole magnet in micro-beam line of HIRFL

International Nuclear Information System (INIS)

Wang Shaoming; Chen Wenjun; Yang Shengli; Cai Guozhu; Guo Yizhen; Zhou Guangming; Man Kaidi; Song Mingtao

2010-01-01

Microbeam irradiation facility is an experiment platform, which can reduce the beam-spot on the irradiated sample to micrometer level, and can accurately locate and count the radioactive particles. It is a powerful research tool for the irradiation material science, irradiation biology, irradiation biomedicine and micro mechanical machining. The microbeam irradiation facility requires the precise work for installation and alignment. These conditions make magnet's change for directions and positions because the location space of dipole magnets in micro-beam line of HIRFL (Heavy Ion Research Facility in Lanzhou) is very small. It is a challenge for the installation and alignment work of magnets. It was solved by transforming coordinates of benchmarks of magnets, which controlled the error of magnet setup within error tolerance range. (authors)

Electrothermally Actuated Microbeams With Varying Stiffness

KAUST Repository

Tella, Sherif Adekunle

2017-11-03

We present axially loaded clamped-guided microbeams that can be used as resonators and actuators of variable stiffness, actuation, and anchor conditions. The applied axial load is implemented by U-shaped electrothermal actuators stacked at one of the beams edges. These can be configured and wired in various ways, which serve as mechanical stiffness elements that control the operating resonance frequency of the structures and their static displacement. The experimental results have shown considerable increase in the resonance frequency and mid-point deflection of the microbeam upon changing the end conditions of the beam. These results can be promising for applications requiring large deflection and high frequency tunability, such as filters, memory devices, and switches. The experimental results are compared to multi-physics finite-element simulations showing good agreement among them.

Time-resolved resonance Raman spectroscopy of intermediates of bacteriorhodopsin: The bK(590) intermediate.

Science.gov (United States)

Terner, J; Hsieh, C L; Burns, A R; El-Sayed, M A

1979-07-01

We have combined microbeam and flow techniques with computer subtraction methods to obtain the resonance Raman spectrum of the short lived batho-intermediate (bK(590)) of bacteriorhodopsin. Comparison of the spectra obtained in (1)H(2)O and (2)H(2)O, as well as the fact that the bK(590) intermediate shows large optical red shifts, suggests that the Schiff base linkage of this intermediate is protonated. The fingerprint region of the spectrum of bK(590), sensitive to the isomeric configuration of the retinal chromophore, does not resemble the corresponding region of the parent bR(570) form. The resonance Raman spectrum of bK(590) as well as the spectra of all of the other main intermediates in the photoreaction cycle of bacteriorhodopsin are discussed and compared with resonance Raman spectra of published model compounds.

Ultra-Compact Raman Spectrometer for Planetary Explorations

Science.gov (United States)

Davis, Derek; Hornef, James; Lucas, John; Elsayed-Ali, Hani; Abedin, M. Nurul

2016-01-01

To develop a compact Raman spectroscopy system with features that will make it suitable for future space missions which require surface landing. Specifically, this system will be appropriate for any mission in which planetary surface samples need to be measured and analyzed.

Static Response of Microbeams due to Capillary and Electrostatic Forces

KAUST Repository

Bataineh, Ahmad M.

2016-03-07

Micro-sensors or micro-switches usually operate under the effect of electrostatic force and could face some environmental effects like humidity, which may lead to condensation underneath the beams and create strong capillary forces. Those tiny structures are principally made of microbeams that can undergo instabilities under the effect of those created huge capillary forces. In fact, during the fabrication of microbeams, there is an important step to separate the beam from its substrate (wet etching). After this step, the microstructure is dried, which may causes the onset of some droplets of water trapped underneath the beam that could bring about a huge capillary force pulling it toward its substrate. If this force is bigger than the microbeam\\'s restoring force, it will become stuck to the substrate. This paper investigates the instability scenarios of both clamped-clamped (straight and curved) and cantilever (straight and curled) microbeams under the effect of capillary and/or electrostatic forces. The reduced order modeling (ROM) based on the Galerkin procedure is used to solve the nonlinear beam equations. The non-ideal boundaries are modeled by adding springs. The volume of the fluid between the beam and the substrate underneath it is varied and the relation between the volume of the water and the stability of the beam is shown. An analysis for the factors of which should be taken in to consideration in the fabrication processes to overcome the instability due to huge capillary forces is done. Also the size of the electrode for the electrostatic force is varied to show the effect on the micro-switch stability. A variation of the pull-in voltage with some specific beam parameters and with more than one case of electrode size is shown. It is found that capillary forces have a pronounced effect on the stability of microbeams. It is also found that the pull-in length decreases as the electrode size increases. It is also shown that the pull-in voltage decreases

Origin of Knudsen forces on heated microbeams

KAUST Repository

Zhu, Taishan

2010-09-09

The presented work probes the fundamentals of Knudsen forces. Using the direct simulation Monte Carlo (DSMC) method, the flows induced by temperature inhomogeneity within a representative configuration and the Knudsen force acting on a heated microbeam are captured as functions of Knudsen number in the entire flow regime. Both flow strength and Knudsen force peak in the transition regime and negative Knudsen force absent in experimental data is observed. The mechanisms of the thermally induced flows and Knudsen forces are studied. It has been found that thermal edge flow is the main driven source for the formation of the Knudsen force on microbeams and domain configuration plays an important role in the process.

High energy ion microbeams and their applications

International Nuclear Information System (INIS)

Bakhru, H.; Nickles, E.; Haberl, A.; Morris, W.G.

1992-01-01

In recent years there has been rapid growth for the development of equipment for forming a focussed beam (0.5 - 2μm) with high energy ions. The State University of New York at Albany ion scanning microprobe has been used for several applications especially in the fields of materials and biological studies. Rutherford backscattering spectroscopy (RBS) and particle-induced x-ray emission (PIXE) analysis have been performed on microelectronic circuits with a spatial resolution of approximately 2 μm. Studies on films of superconductors (YBa CuO) will be presented. Applications of microbeams for the biological studies and analytical techniques will be presented. Current and future role of microbeams and their limitations will be discussed. (author)

Physiologically gated microbeam radiation using a field emission x-ray source array

Energy Technology Data Exchange (ETDEWEB)

Chtcheprov, Pavel, E-mail: PavelC@unc.edu, E-mail: zhou@email.unc.edu [Department of Biomedical Engineering, University of North Carolina, 152 MacNider Hall, Campus Box 7575, Chapel Hill, North Carolina 27599 (United States); Burk, Laurel; Inscoe, Christina; Ger, Rachel; Hadsell, Michael; Lu, Jianping [Department of Physics and Astronomy, University of North Carolina, Phillips Hall, CB #3255, 120 East Cameron Avenue, Chapel Hill, North Carolina 27599 (United States); Yuan, Hong [Department of Radiology, University of North Carolina, 2006 Old Clinic, CB #7510, Chapel Hill, North Carolina 27599 (United States); Zhang, Lei [Department of Applied Physical Sciences, University of North Carolina, Chapman Hall, CB#3216, Chapel Hill, North Carolina 27599 (United States); Chang, Sha [Department of Radiation Oncology, University of North Carolina, 101 Manning Drive, Chapel Hill, North Carolina 27514 and UNC Lineberger Comprehensive Cancer Center, University of North Carolina, 101 Manning Drive, Chapel Hill, North Carolina 27514 (United States); Zhou, Otto, E-mail: PavelC@unc.edu, E-mail: zhou@email.unc.edu [Department of Physics and Astronomy, University of North Carolina, Phillips Hall, CB #3255, 120 East Cameron Avenue, Chapel Hill, North Carolina 27599 and UNC Lineberger Comprehensive Cancer Center, University of North Carolina, 101 Manning Drive, Chapel Hill, North Carolina 27514 (United States)

2014-08-15

Purpose: Microbeam radiation therapy (MRT) uses narrow planes of high dose radiation beams to treat cancerous tumors. This experimental therapy method based on synchrotron radiation has been shown to spare normal tissue at up to 1000 Gy of peak entrance dose while still being effective in tumor eradication and extending the lifetime of tumor-bearing small animal models. Motion during treatment can lead to significant movement of microbeam positions resulting in broader beam width and lower peak to valley dose ratio (PVDR), which reduces the effectiveness of MRT. Recently, the authors have demonstrated the feasibility of generating microbeam radiation for small animal treatment using a carbon nanotube (CNT) x-ray source array. The purpose of this study is to incorporate physiological gating to the CNT microbeam irradiator to minimize motion-induced microbeam blurring. Methods: The CNT field emission x-ray source array with a narrow line focal track was operated at 160 kVp. The x-ray radiation was collimated to a single 280 μm wide microbeam at entrance. The microbeam beam pattern was recorded using EBT2 Gafchromic{sup ©} films. For the feasibility study, a strip of EBT2 film was attached to an oscillating mechanical phantom mimicking mouse chest respiratory motion. The servo arm was put against a pressure sensor to monitor the motion. The film was irradiated with three microbeams under gated and nongated conditions and the full width at half maximums and PVDRs were compared. An in vivo study was also performed with adult male athymic mice. The liver was chosen as the target organ for proof of concept due to its large motion during respiration compared to other organs. The mouse was immobilized in a specialized mouse bed and anesthetized using isoflurane. A pressure sensor was attached to a mouse's chest to monitor its respiration. The output signal triggered the electron extraction voltage of the field emission source such that x-ray was generated only

Ion microbeam irradiation for radiobiology and radical chemistry: status and prospect

Energy Technology Data Exchange (ETDEWEB)

Khodja, H, E-mail: hicham.khodja@cea.fr [CEA, IRAMIS, SIS2M, LEEL, 91191 Gif-sur-Yvette (France); CNRS, UMR 3299, SIS2M, LEEL, 91191 Gif-sur-Yvette (France)

2011-01-01

Ion microbeams are commonly used to study local irradiation effects in living cells, as it has been established that ion beam irradiations can lead to deleterious changes in cells that are not struck directly by the microbeam. Such changes, which take place over distances long compared to the size of the irradiation spot and for times long compared to the time of irradiation, are collectively termed radiation-induced bystander effect or RIBE. Free-radical chemistry is frequently invoked to explain the RIBE but no unified model is available at present. Ion microbeams when coupled with advanced methods for observing free radicals are the tools of choice for investigating the chemistry and biological processes governing RIBE.

THE ROLE OF RAMAN SPECTROSCOPY IN THE ANALYTICAL CHEMISTRY OF POTABLE WATER

Science.gov (United States)

Advances in instrumentation are making Raman spectroscopy the tool of choice for an increasing number of chemical applications. For example, many recalcitrant industrial process monitoring problems have been solved in recent years with in-line Raman spectrometers. Raman is attr...

Nanoscale and submicron fatigue crack growth in nickel microbeams

International Nuclear Information System (INIS)

Yang, Y.; Yao, N.; Imasogie, B.; Soboyejo, W.O.

2007-01-01

This paper presents a novel edge-notched microbeam technique for the study of short fatigue crack growth. The technique is used to study submicron and nanoscale fatigue in LIGA Ni thin films with columnar microstructures. The edge-notched microbeams were fabricated within LIGA Ni thin films, using focused ion beam (FIB) techniques. The microbeams were then cyclically deformed to failure at a stress ratio of 0.1. Different slip-band structures were observed below the nanoscale notches. Cyclic deformation resulted in the formation of primary slip bands below the notch. Subsequent crack growth then occurred by the unzipping of fatigue cracks along intersecting slip bands. The effects of the primary slip bands were idealized using dislocation-based models. These were used to estimate the intrinsic fatigue threshold and the fatigue endurance limit. The estimates from the model are shown to be consistent with experimental data from prior stress-life experiments and current/prior fatigue threshold estimates

Live cell imaging at the Munich ion microbeam SNAKE - a status report.

Science.gov (United States)

Drexler, Guido A; Siebenwirth, Christian; Drexler, Sophie E; Girst, Stefanie; Greubel, Christoph; Dollinger, Günther; Friedl, Anna A

2015-02-18

Ion microbeams are important tools in radiobiological research. Still, the worldwide number of ion microbeam facilities where biological experiments can be performed is limited. Even fewer facilities combine ion microirradiation with live-cell imaging to allow microscopic observation of cellular response reactions starting very fast after irradiation and continuing for many hours. At SNAKE, the ion microbeam facility at the Munich 14 MV tandem accelerator, a large variety of biological experiments are performed on a regular basis. Here, recent developments and ongoing research projects at the ion microbeam SNAKE are presented with specific emphasis on live-cell imaging experiments. An overview of the technical details of the setup is given, including examples of suitable biological samples. By ion beam focusing to submicrometer beam spot size and single ion detection it is possible to target subcellular structures with defined numbers of ions. Focusing of high numbers of ions to single spots allows studying the influence of high local damage density on recruitment of damage response proteins.

Heavy ion microbeam system for study of single event effects

International Nuclear Information System (INIS)

Kamiya, Tomihiro; Utsunomiya, Nobuhiro; Minehara, Eiichi; Tanaka, Ryuichi; Ohmura, Miyoshi; Kohno, Kazuhiro; Iwamoto, Eiji.

1992-01-01

A high-energy heavy ion microbeam system has been developed and installed on a beam line of a 3 MV tandem electrostatic accelerator mainly for analysis of basic mechanism of single event upset (SEU) of semiconductor devices in spacecraft. The SEU is now the most serious problem for highly reliable spacecraft electronics system with long space mission. However, the mechanism has not been understood on the basis of microscopic process of SEU. The SEU phenomena depends not only upon hitting particles, but also upon the hit position on the microcircuit. To observe the transient charge pulse from a SEU, a single ion particle must hit exactly the desired position of the microcircuit. Such an experiment requires the microbeam spot size within 1 μm, the beam positioning accuracy within ±1 μm, and single ion hitting. The microbeam system has been designed to meet the above technical requirements. The system is equipped with two lens systems: one to control the target beam current in a wide range down to extremely low current without any change of the beam optics, and the other to focus heavy ion beams within a spot size of 1 μm. The final goal is to hit a microscopic target area with a single 15 MeV nickel ion. The beam spot size has been evaluated by Gaussian fitting of secondary electron profiles with microbeam scanning across the fine Cu mesh. The single ion detection has been also tested to generate a trigger signal for closing beam shutter to prevent further hits. This paper outlines the new microbeam system and describes methods to realize these techniques. (author)

The first interdisciplinary experiments at the IMP high energy microbeam

Energy Technology Data Exchange (ETDEWEB)

Du, Guanghua; Guo, Jinlong; Wu, Ruqun; Guo, Na; Liu, Wenjing; Ye, Fei; Sheng, Lina; Li, Qiang [Institute of Modern Physics (IMP), Chinese Academy of Sciences, Lanzhou (China); Li, Huiyun [Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen (China)

2015-04-01

The high energy beam of tens to hundred MeV/u ions possesses mm-to-cm penetration depth in materials and can be easily extracted into air without significant energy loss and beam scattering. Combination of high energy ions and microbeam technology facilitates the microprobe application to many practical studies in large scale samples. The IMP heavy ion microbeam facility has recently been integrated with microscopic positioning and targeting irradiation system. This paper introduced the first interdisciplinary experiments performed at the IMP microbeam facility using the beam of 80.5 MeV/u carbon ions. Bystander effect induction via medium transferring was not found in the micro-irradiation study using HeLa cells. The mouse irradiation experiment demonstrated that carbon irradiation of 10 Gy dose to its tuberomammillary nucleus did not impair the sleep nerve system. The fault injection attack on RSA (Rivest–Shamir–Adleman) decryption proved that the commercial field-programmable gate array chip is vulnerable in single event effect to low linear-energy-transfer carbon irradiation, and the attack can cause the leakage of RSA private key. This work demonstrates the potential of high energy microbeam in its application to biology, biomedical, radiation hardness, and information security studies.

Negative Knudsen force on heated microbeams

KAUST Repository

Zhu, Taishan; Ye, Wenjing; Zhang, Jun

2011-01-01

Knudsen force acting on a heated microbeam adjacent to a cold substrate in a rarefied gas is a mechanical force created by unbalanced thermal gradients. The measured force has its direction pointing towards the side with a lower thermal gradient

Large-area, uniform and low-cost dual-mode plasmonic naked-eye colorimetry and SERS sensor with handheld Raman spectrometer.

Science.gov (United States)

Xu, Zhida; Jiang, Jing; Wang, Xinhao; Han, Kevin; Ameen, Abid; Khan, Ibrahim; Chang, Te-Wei; Liu, Gang Logan

2016-03-21

We demonstrated a highly-sensitive, wafer-scale, highly-uniform plasmonic nano-mushroom substrate based on plastic for naked-eye plasmonic colorimetry and surface-enhanced Raman spectroscopy (SERS). We gave it the name FlexBrite. The dual-mode functionality of FlexBrite allows for label-free qualitative analysis by SERS with an enhancement factor (EF) of 10(8) and label-free quantitative analysis by naked-eye colorimetry with a sensitivity of 611 nm RIU(-1). The SERS EF of FlexBrite in the wet state was found to be 4.81 × 10(8), 7 times stronger than in the dry state, making FlexBrite suitable for aqueous environments such as microfluid systems. The label-free detection of biotin-streptavidin interaction by both SERS and colorimetry was demonstrated with FlexBrite. The detection of trace amounts of the narcotic drug methamphetamine in drinking water by SERS was implemented with a handheld Raman spectrometer and FlexBrite. This plastic-based dual-mode nano-mushroom substrate has the potential to be used as a sensing platform for easy and fast analysis in chemical and biological assays.

Electron microbeam specifications for use in cell irradiation experiments

International Nuclear Information System (INIS)

Kim, E.-H.; Choi, M.-C.; Lee, D.-H.; Chang, M.; Kang, C.-S.

2003-01-01

The microbeam irradiation system was devised originally to identify the hit and unhit cells by confining the beam within the target cell. The major achievement through the microbeam experiment studies has turned out to be the discovery of the 'bystander effect'. Microbeam experiments have been performed with alpha and proton beams in major and with soft x-rays in minor. The study with electron microbeam has been deferred mainly due to the difficulty in confining the electron tracks within a single target cell. In this paper, the electron microbeam irradiation system under development in Korea is introduced in terms of the beam specifications. The KIRAMS electron microbeam irradiation system consists of an electron gun, a vacuum chamber for beam collimation into 5 μm in diameter and a biology stage. The beam characteristics in terms of current and energy spectrum of the electrons entering a target cell and its neighbor cells were investigated by Monte Carlo simulation for the electron source energies of 25, 50, 75 and 100 keV. Energy depositions in the target cell and the neighbor cells were also calculated. The beam attenuation in current and energy occurs while electrons pass through the 2 μm-thick Mylar vacuum window, 100 μm-thick air gap and the 2 μm-thick Mylar bottom of cell dish. With 25 keV electron source, 80 % of decrease in current and 30 % of decrease in average energy were estimated before entering the target cell. With 75 keV electron source, on the other hand, 55 % of decrease in current and less than 1 % of decrease in average energy were estimated. Average dose per single collimated electron emission was 0.067 cGy to the target cell nucleus of 5 μm in diameter and 0.030 cGy to the cytoplasm of 2.5 μm in thickness with 25 keV electron source while they were 0.15 cGy and 0.019 cGy, respectively, with 75 keV electron source. The multiple scattering of electrons resulted in energy deposition in the neighbor cells as well. Dose to the first

Optical properties behavior of three optical filters and a mirror used in the internal optical head of a Raman laser spectrometer after exposed to proton radiation

Science.gov (United States)

Guembe, V.; Alvarado, C. G.; Fernández-Rodriguez, M.; Gallego, P.; Belenguer, T.; Díaz, E.

2017-11-01

The Raman Laser Spectrometer is one of the ExoMars Pasteur Rover's payload instruments that is devoted to the analytical analysis of the geochemistry content and elemental composition of the observed minerals provided by the Rover through Raman spectroscopy technique. One subsystem of the RLS instrument is the Internal Optical Head unit (IOH), which is responsible for focusing the light coming from the laser onto the mineral under analysis and for collecting the Raman signal emitted by the excited mineral. The IOH is composed by 4 commercial elements for Raman spectroscopy application; 2 optical filters provided by Iridian Spectral Technologies Company and 1 optical filter and 1 mirror provided by Semrock Company. They have been exposed to proton radiation in order to analyze their optical behaviour due to this hostile space condition. The proton irradiation test was performed following the protocol of LINES lab (INTA). The optical properties have been studied through transmittance, reflectance and optical density measurements, the final results and its influence on optical performances are presented.

Active mems microbeam device for gas detection

KAUST Repository

Bouchaala, Adam M.; Jaber, Nizar; Younis, Mohammad I.

2017-01-01

Sensors and active switches for applications in gas detection and other fields are described. The devices are based on the softening and hardening nonlinear response behaviors of microelectromechanical systems (MEMS) clamped-clamped microbeams

Comparison of fluorescence rejection methods of baseline correction and shifted excitation Raman difference spectroscopy

Science.gov (United States)

Cai, Zhijian; Zou, Wenlong; Wu, Jianhong

2017-10-01

Raman spectroscopy has been extensively used in biochemical tests, explosive detection, food additive and environmental pollutants. However, fluorescence disturbance brings a big trouble to the applications of portable Raman spectrometer. Currently, baseline correction and shifted-excitation Raman difference spectroscopy (SERDS) methods are the most prevailing fluorescence suppressing methods. In this paper, we compared the performances of baseline correction and SERDS methods, experimentally and simulatively. Through the comparison, it demonstrates that the baseline correction can get acceptable fluorescence-removed Raman spectrum if the original Raman signal has good signal-to-noise ratio, but it cannot recover the small Raman signals out of large noise background. By using SERDS method, the Raman signals, even very weak compared to fluorescence intensity and noise level, can be clearly extracted, and the fluorescence background can be completely rejected. The Raman spectrum recovered by SERDS has good signal to noise ratio. It's proved that baseline correction is more suitable for large bench-top Raman system with better quality or signal-to-noise ratio, while the SERDS method is more suitable for noisy devices, especially the portable Raman spectrometers.

Semiconductor analysis with a channeled helium microbeam

International Nuclear Information System (INIS)

Ingarfield, S.A.; McKenzie, C.D.; Short, K.T.; Williams, J.S.

1981-01-01

This paper describes the use of a channeled helium microbeam for analysis of damage and dopant distributions in semiconductors. Practical difficulties and potential problems associated with the channeling of microbeams in semiconductors have been examined. In particular, the following factors have been characterised: i) the effect of both convergence of focused beam and beam scanning on the quality of channeling; ii) damage produced by the probe ions; and iii) local beam heating effects arising from high current densities. Acceptable channeling has been obtained (minimum yield approaching 4%) under a variety of focusing and scanning conditions which are suitable for analysis of device structures. The capabilities of the technique are demonstrated by monitoring variations in local damage and impurity depth distributions across a narrow (<2mm) region of an ion implanted silicon wafer

Applications of Raman spectroscopy to gemology.

Science.gov (United States)

Bersani, Danilo; Lottici, Pier Paolo

2010-08-01

Being nondestructive and requiring short measurement times, a low amount of material, and no sample preparation, Raman spectroscopy is used for routine investigation in the study of gemstone inclusions and treatments and for the characterization of mounted gems. In this work, a review of the use of laboratory Raman and micro-Raman spectrometers and of portable Raman systems in the gemology field is given, focusing on gem identification and on the evaluation of the composition, provenance, and genesis of gems. Many examples are shown of the use of Raman spectroscopy as a tool for the identification of imitations, synthetic gems, and enhancement treatments in natural gemstones. Some recent developments are described, with particular attention being given to the semiprecious stone jade and to two important organic materials used in jewelry, i.e., pearls and corals.

X-ray microbeams: Tumor therapy and central nervous system research

International Nuclear Information System (INIS)

Dilmanian, F.A.; Qu, Y.; Liu, S.; Cool, C.D.; Gilbert, J.; Hainfeld, J.F.; Kruse, C.A.; Laterra, J.; Lenihan, D.; Nawrocky, M.M.; Pappas, G.; Sze, C.-I.; Yuasa, T.; Zhong, N.; Zhong, Z.; McDonald, J.W.

2005-01-01

Irradiation with parallel arrays of thin, planar slices of X-ray beams (microplanar beams, or microbeams) spares normal tissue, including the central nervous system (CNS), and preferentially damages tumors. The effects are mediated, at least in part, by the tissue's microvasculature that seems to effectively repair itself in normal tissue but fails to do so in tumors. Consequently, the therapeutic index of single-fraction unidirectional microbeam irradiations has been shown to be larger than that of single-fraction unidirectional unsegmented beams in treating the intracranial rat 9L gliosarcoma tumor model (9LGS) and the subcutaneous murine mammary carcinoma EMT-6. This paper presents results demonstrating that individual microbeams, or arrays of parallel ones, can also be used for targeted, selective cell ablation in the CNS, and also to induce demyelination. The results highlight the value of the method as a powerful tool for studying the CNS through selective cell ablation, besides its potential as a treatment modality in clinical oncology

Other applications of ion microbeams

International Nuclear Information System (INIS)

Cookson, J.A.

1987-01-01

The paper concerns the analytical and non-analytical applications of ion microbeams. The analytical applications considered include:-fusion research, environmental studies, ion implantations and criminology, and each is briefly discussed. Non-analytical applications in which nuclear microprobes have been used include:-thickness and uniformity measurements, energy loss radiography, channelling contrast, tomography, topography, ion implantation, and detector testing, and these are also discussed. (UK)

Elemental analysis techniques using proton microbeam

International Nuclear Information System (INIS)

Sakai, Takuro; Oikawa, Masakazu; Sato, Takahiro

2005-01-01

Proton microbeam is a powerful tool for two-dimensional elemental analysis. The analysis is based on Particle Induced X-ray Emission (PIXE) and Particle Induced Gamma-ray Emission (PIGE) techniques. The paper outlines the principles and instruments, and describes the dental application has been done in JAERI Takasaki. (author)

Study of transient current induced by heavy-ion microbeams in Si and GaAs

Energy Technology Data Exchange (ETDEWEB)

Hirao, Toshio; Nashiyama, Isamu; Kamiya, Tomihiro; Suda, Tamotu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

1997-03-01

Heavy-ion microbeams were applied to the study of mechanism of single event upset (SEU). Transient current induced in p{sup +}n junction diodes by strike of heavy ion microbeam were measured by using a high-speed digitizing sampling system. (author)

Multifrequency Excitation of a Clamped-Clamped Microbeam

KAUST Repository

Jaber, Nizar; Ramini, Abdallah; Younis, Mohammad I.

2016-01-01

. These microbeams are fabricated using polyimide as structural layer coated with nickel form top and chromium and gold layers from bottom. We demonstrate the excitation of additive and subtractive type resonance. We show that by properly tuning the frequency

DEB-silicone rubber hydrogen absorbing Raman detection technology research

International Nuclear Information System (INIS)

Yang Suolong; Zhong Jingrong; Wang Huang; Yang Kaixu; Xiao Jiqun; Liu Jiaxi; Liao Junsheng

2012-01-01

The DEB-Pd/C hydrogen getter powder and DEB-Pd/C-silicone rubber getter film were prepared and used for hydrogen detection in close systems by laser Raman method. The DEB alkanes Raman peak intensity changes with the getter time were monitored by Raman spectrometer. As a result, silicone rubber has good compatibility with DEB getter, slow access to hydrogen and good flexible. The alkanes peak intensity-getter time followed a exponential rule. DEB getter films are suitable for Raman on-line monitor of cumulative hydrogen of a closed system at long time. (authors)

Origin of Knudsen forces on heated microbeams

KAUST Repository

Zhu, Taishan; Ye, Wenjing

2010-01-01

microbeam are captured as functions of Knudsen number in the entire flow regime. Both flow strength and Knudsen force peak in the transition regime and negative Knudsen force absent in experimental data is observed. The mechanisms of the thermally induced

Multifrequency excitation of a clamped–clamped microbeam: Analytical and experimental investigation

KAUST Repository

Jaber, Nizar

2016-03-14

Using partial electrodes and a multifrequency electrical source, we present a large-bandwidth, large-amplitude clamped–clamped microbeam resonator excited near the higher order modes of vibration. We analytically and experimentally investigate the nonlinear dynamics of the microbeam under a two-source harmonic excitation. The first-frequency source is swept around the first three modes of vibration, whereas the second source frequency remains fixed. New additive and subtractive resonances are demonstrated. We illustrated that by properly tuning the frequency and amplitude of the excitation force, the frequency bandwidth of the resonator is controlled. The microbeam is fabricated using polyimide as a structural layer coated with nickel from the top and chromium and gold layers from the bottom. Using the Galerkin method, a reduced order model is derived to simulate the static and dynamic response of the device. A good agreement between the theoretical and experimental data are reported.

Multifrequency excitation of a clamped–clamped microbeam: Analytical and experimental investigation

KAUST Repository

Jaber, Nizar; Ramini, Abdallah; Younis, Mohammad I.

2016-01-01

Using partial electrodes and a multifrequency electrical source, we present a large-bandwidth, large-amplitude clamped–clamped microbeam resonator excited near the higher order modes of vibration. We analytically and experimentally investigate the nonlinear dynamics of the microbeam under a two-source harmonic excitation. The first-frequency source is swept around the first three modes of vibration, whereas the second source frequency remains fixed. New additive and subtractive resonances are demonstrated. We illustrated that by properly tuning the frequency and amplitude of the excitation force, the frequency bandwidth of the resonator is controlled. The microbeam is fabricated using polyimide as a structural layer coated with nickel from the top and chromium and gold layers from the bottom. Using the Galerkin method, a reduced order model is derived to simulate the static and dynamic response of the device. A good agreement between the theoretical and experimental data are reported.

The application of microbeam in the research on radiation-induced bystander effects

International Nuclear Information System (INIS)

Xiong Jie; Han Ling

2002-01-01

There has been more and more attention to the phenomenon known as radiation-induced bystander effects, which will have a tremendous effect on the research in low -dose radiation biological effects. However, due to the stochastic nature of energy deposition and the random position of tracts, direct evidence for bystander effects and exact results of single particle interacts with a cell cannot be provided by using conventional broad-field irradiation. The availability of microbeam, especially the single particle microbeam in the world, whereby individual cells or precise location of cells can be irradiated with either a single or an exact number of particles provides a useful tool for the research on radiation-induced bystander effects. The author describes the radiation -induced bystander effect and the application of microbeam in the research on it

Development of an intermediate energy heavy-ion micro-beam irradiation system

International Nuclear Information System (INIS)

Song Mingtao; Wang Zhiguang; He Yuan; Gao Daqing; Yang Xiaotian; Liu Jie; Su Hong; Man Kaidi; Sheng Li'na

2008-01-01

The micro-beam irradiation system, which focuses the beam down the micron order and precisely delivers a predefined number of ions to a predefined spot of micron order, is a powerful tool for radio-biology, radio-biomedicine and micromachining. The Institute of Modern Physics of Chinese Academy of Sciences is developing a heavy-ion micro-beam irradiation system up to intermediate energy. Based on the intermediate and low energy beam provided by Heavy Ion Research Facility of Lanzhou, the micro-beam system takes the form of the magnetic focusing. The heavy-ion beam is conducted to the basement by a symmetrical achromatic system consisting of two vertical bending magnets and a quadrupole in between. Then a beam spot of micron order is formed by magnetic triplet quadrupole of very high gradient. The sample can be irradiated either in vacuum or in the air. This system will be the first opening platform capable of providing heavy ion micro-beam, ranging from low (10 MeV/u) to intermediate energy (100 MeV/u), for irradiation experiment with positioning and counting accuracy. Target material may be biology cell, tissue or other non-biological materials. It will be a help for unveiling the essence of heavy-ion interaction with matter and also a new means for exploring the application of heavy-ion irradiation. (authors)

Dynamic response of an electrostatically actuated microbeam to drop-table test

International Nuclear Information System (INIS)

Ouakad, Hassen M; Younis, Mohammad I; Alsaleem, Fadi

2012-01-01

In this paper, we present a theoretical and experimental investigation into the dynamic response of an electrostatically actuated microbeam when subjected to drop-table test. For the theoretical part, a reduced-order model based on an Euler–Bernoulli beam model is utilized. The model accounts for the electrostatic bias on the microbeam and the shock pulse of the drop-table test. Simulation results are presented showing the combined effect of electrostatic force and mechanical shock in triggering early pull-in instability of the cantilever microbeams. The analytical simulation results are validated by finite-element results for the static response. Dynamic pull-in threshold as a function of the mechanical shock amplitude is shown over a wide range of shock spanning hundreds of thousands of g up to zero g. For the experimental part, a micromachined cantilever beam made of gold of length 50 µm is subjected to drop-table tests while being biased by electrostatic loads. Several experimental data are shown demonstrating the phenomenon of collapse due to the combined shock and electrostatic forces. It is also demonstrated that by biasing short and too stiff microbeams with electrostatic voltages, their stiffness is weakened. This lowers their threshold of collapse considerably to the range of acceleration that enables testing them with in-house shock testing equipments, such as drop-table tests. (paper)

Multifrequency Excitation of a Clamped-Clamped Microbeam

KAUST Repository

Jaber, Nizar R.

2016-01-20

We present analytical and experimental investigation of an electrically actuated clamped-clamped microbeam under a twosource harmonic excitation. The first frequency is swept around the first mode of vibration where the second one is fixed. These microbeams are fabricated using polyimide as structural layer coated with nickel form top and chromium and gold layers from bottom. We demonstrate the excitation of additive and subtractive type resonance. We show that by properly tuning the frequency and the amplitude of the excitation force, the frequency bandwidth of the resonator is increased. Theoretically, we solved the eigenvalue problem for different axial forces to find the natural frequencies ratio that match the experimental values. Using Galerkin method, a reduced order model is derived to simulate the static and dynamic response of the device where using three symmetric mode shapes provided a good agreement with experimental data. © Copyright 2015 by ASME.

WE-AB-BRB-12: Nanoscintillator Fiber-Optic Detector System for Microbeam Radiation Therapy Dosimetry

Energy Technology Data Exchange (ETDEWEB)

Rivera, J [University of North Carolina and North Carolina State University, Chapel Hill, NC (United States); Dooley, J; Chang, S [University of North Carolina School of Medicine, Chapel Hill, NC (United States); Belley, M; Yoshizumi, T [Duke University Medical Center, Durham, NC (United States); Stanton, I; Langloss, B; Therien, M [Duke University, Durham, NC (United States)

2015-06-15

Purpose: Microbeam Radiation Therapy (MRT) is an experimental radiation therapy that has demonstrated a higher therapeutic ratio than conventional radiation therapy in animal studies. There are several roadblocks in translating the promising treatment technology to clinical application, one of which is the lack of a real-time, high-resolution dosimeter. Current clinical radiation detectors have poor spatial resolution and, as such, are unsuitable for measuring microbeams with submillimeter-scale widths. Although GafChromic film has high spatial resolution, it lacks the real-time dosimetry capability necessary for MRT preclinical research and potential clinical use. In this work we have demonstrated the feasibility of using a nanoscintillator fiber-optic detector (nanoFOD) system for real-time MRT dosimetry. Methods: A microplanar beam array is generated using a x-ray research irradiator and a custom-made, microbeam-forming collimator. The newest generation nanoFOD has an effective size of 70 µm in the measurement direction and was calibrated against a kV ion chamber (RadCal Accu-Pro) in open field geometry. We have written a computer script that performs automatic data collection with immediate background subtraction. A computer-controlled detector positioning stage is used to precisely measure the microbeam peak dose and beam profile by translating the stage during data collection. We test the new generation nanoFOD system, with increased active scintillation volume, against the previous generation system. Both raw and processed data are time-stamped and recorded to enable future post-processing. Results: The real-time microbeam dosimetry system worked as expected. The new generation dosimeter has approximately double the active volume compared to the previous generation resulting in over 900% increase in signal. The active volume of the dosimeter still provided the spatial resolution that meets the Nyquist criterion for our microbeam widths. Conclusion: We have

Parameter identification of an electrically actuated imperfect microbeam

KAUST Repository

Ruzziconi, Laura; Younis, Mohammad I.; Lenci, Stefano

2013-01-01

In this study we consider a microelectromechanical system (MEMS) and focus on extracting analytically the model parameters that describe its non-linear dynamic features accurately. The device consists of a clamped-clamped polysilicon microbeam

Differentiating the growth phases of single bacteria using Raman spectroscopy

Science.gov (United States)

Strola, S. A.; Marcoux, P. R.; Schultz, E.; Perenon, R.; Simon, A.-C.; Espagnon, I.; Allier, C. P.; Dinten, J.-M.

2014-03-01

In this paper we present a longitudinal study of bacteria metabolism performed with a novel Raman spectrometer system. Longitudinal study is possible with our Raman setup since the overall procedure to localize a single bacterium and collect a Raman spectrum lasts only 1 minute. Localization and detection of single bacteria are performed by means of lensfree imaging, whereas Raman signal (from 600 to 3200 cm-1) is collected into a prototype spectrometer that allows high light throughput (HTVS technology, Tornado Spectral System). Accomplishing time-lapse Raman spectrometry during growth of bacteria, we observed variation in the net intensities for some band groups, e.g. amides and proteins. The obtained results on two different bacteria species, i.e. Escherichia coli and Bacillus subtilis clearly indicate that growth affects the Raman chemical signature. We performed a first analysis to check spectral differences and similarities. It allows distinguishing between lag, exponential and stationary growth phases. And the assignment of interest bands to vibration modes of covalent bonds enables the monitoring of metabolic changes in bacteria caused by growth and aging. Following the spectra analysis, a SVM (support vector machine) classification of the different growth phases is presented. In sum this longitudinal study by means of a compact and low-cost Raman setup is a proof of principle for routine analysis of bacteria, in a real-time and non-destructive way. Real-time Raman studies on metabolism and viability of bacteria pave the way for future antibiotic susceptibility testing.

Residual stress measurement method in MEMS microbeams using frequency shift data

International Nuclear Information System (INIS)

Somà, Aurelio; Ballestra, Alberto

2009-01-01

The dynamical behaviour of a set of gold microbeams affected by residual stress has been studied. Experimental frequency shift curves were obtained by increasing the dc voltage applied to the specimens. Comparison with different analytical and numerical models has been carried out in order to identify both analytical and finite element models in the presence of residual stress. Residual strain and stress, due to the fabrication process, have been widely reported in the literature in both out-of-plane microcantilevers and clamped–clamped microbeams by using mainly the value of pull-in voltage and static deflection data. In the case of a microcantilever, an accurate modelling includes the effect of the initial curvature due to microfabrication. In double-clamped microbeams, a pre-load applied by tensile stress is considered. A good correspondence is pointed out between measurements and numerical models so that the residual stress effect can be evaluated for different geometrical configurations

[Surface-enhanced Raman spectroscopy analysis of thiabendazole pesticide].

Science.gov (United States)

Lin, Lei; Wu, Rui-mei; Liu, Mu-hua; Wang, Xiao-bin; Yan, Lin-yuan

2015-02-01

Surface-enhanced Raman spectroscopy (SERS) technique was used to analyze the Raman peaks of thiabendazole pesticides in the present paper. Surface enhanced substrates of silver nanoparticle were made based on microwave technology. Raman signals of thiabendazole were collected by laser Micro-Raman spectrometer with 514. 5 and 785 nm excitation wavelengths, respectively. The Raman peaks at different excitation wavelengths were analyzed and compared. The Raman peaks 782 and 1 012 at 785 nm excitation wavelength were stronger, which were C--H out-of-plane vibrations. While 1284, 1450 and 1592 cm(-1) at 514.5 nm excitation wavelength were stronger, which were vng and C==N stretching. The study results showed that the intensity of Raman peak and Raman shift at different excitation wavelengths were different And strong Raman signals were observed at 782, 1012, 1284, 1450 and 1592 cm(-1) at 514.5 and 785 nm excitation wavelengths. These characteristic vibrational modes are characteristic Raman peaks of carbendazim pesticide. The results can provide basis for the rapid screening of pesticide residue in agricultural products and food based on Raman spectrum.

Synchrotron x-ray microbeam characteristics for x-ray fluorescence analysis

International Nuclear Information System (INIS)

Iida, Atsuo; Noma, Takashi

1995-01-01

X-ray fluorescence analysis using a synchrotron x-ray microprobe has become an indispensable technique for non-destructive micro-analysis. One of the most important parameters that characterize the x-ray microbeam system for x-ray fluorescence analysis is the beam size. For practical analysis, however, the photon flux, the energy resolution and the available energy range are also crucial. Three types of x-ray microbeam systems, including monochromatic and continuum excitation systems, were compared with reference to the sensitivity, the minimum detection limit and the applicability to various types of x-ray spectroscopic analysis. 16 refs., 5 figs

New Method to Study the Vibrational Modes of Biomolecules in the Terahertz Range Based on a Single-Stage Raman Spectrometer.

Science.gov (United States)

Kalanoor, Basanth S; Ronen, Maria; Oren, Ziv; Gerber, Doron; Tischler, Yaakov R

2017-03-31

The low-frequency vibrational (LFV) modes of biomolecules reflect specific intramolecular and intermolecular thermally induced fluctuations that are driven by external perturbations, such as ligand binding, protein interaction, electron transfer, and enzymatic activity. Large efforts have been invested over the years to develop methods to access the LFV modes due to their importance in the studies of the mechanisms and biological functions of biomolecules. Here, we present a method to measure the LFV modes of biomolecules based on Raman spectroscopy that combines volume holographic filters with a single-stage spectrometer, to obtain high signal-to-noise-ratio spectra in short acquisition times. We show that this method enables LFV mode characterization of biomolecules even in a hydrated environment. The measured spectra exhibit distinct features originating from intra- and/or intermolecular collective motion and lattice modes. The observed modes are highly sensitive to the overall structure, size, long-range order, and configuration of the molecules, as well as to their environment. Thus, the LFV Raman spectrum acts as a fingerprint of the molecular structure and conformational state of a biomolecule. The comprehensive method we present here is widely applicable, thus enabling high-throughput study of LFV modes of biomolecules.

Advances in radiobiological studies using a microbeam

International Nuclear Information System (INIS)

Hei, Tom K.; Brenner, David J.; Geard, Charles R.; Ballas, Leslie K.

2009-01-01

Recent developments in microbeam technology have made drastic improvements in particle delivery, focusing, image processing and precision to allow for rapid advances in our knowledge in radiation biology. The unequivocal demonstration that targeted cytoplasmic irradiation results in mutations in the nuclei of hit cells and the presence of non-targeted effects, all made possible using a charged particle microbeam, results in a paradigm shift in our basic understanding of the target theory and other radiation-induced low dose effects. The demonstration of a bystander effect in 3D human tissue and whole organisms have shown the potential relevance of the non-targeted response in human health. The demonstration of delayed mutations in the progeny of bystander cells suggest that genomic instability induced following ionizing radiation exposure is not dependent on direct damage to cell nucleus. The identification of specific signaling pathways provides mechanistic insight on the nature of the bystander process. (author)

Raman-in-SEM, a multimodal and multiscale analytical tool: performance for materials and expertise.

Science.gov (United States)

Wille, Guillaume; Bourrat, Xavier; Maubec, Nicolas; Lahfid, Abdeltif

2014-12-01

The availability of Raman spectroscopy in a powerful analytical scanning electron microscope (SEM) allows morphological, elemental, chemical, physical and electronic analysis without moving the sample between instruments. This paper documents the metrological performance of the SEMSCA commercial Raman interface operated in a low vacuum SEM. It provides multiscale and multimodal analyses as Raman/EDS, Raman/cathodoluminescence or Raman/STEM (STEM: scanning transmission electron microscopy) as well as Raman spectroscopy on nanomaterials. Since Raman spectroscopy in a SEM can be influenced by several SEM-related phenomena, this paper firstly presents a comparison of this new tool with a conventional micro-Raman spectrometer. Then, some possible artefacts are documented, which are due to the impact of electron beam-induced contamination or cathodoluminescence contribution to the Raman spectra, especially with geological samples. These effects are easily overcome by changing or adapting the Raman spectrometer and the SEM settings and methodology. The deletion of the adverse effect of cathodoluminescence is solved by using a SEM beam shutter during Raman acquisition. In contrast, this interface provides the ability to record the cathodoluminescence (CL) spectrum of a phase. In a second part, this study highlights the interest and efficiency of the coupling in characterizing micrometric phases at the same point. This multimodal approach is illustrated with various issues encountered in geosciences. Copyright © 2014 Elsevier Ltd. All rights reserved.

Live cell imaging at the Munich ion microbeam SNAKE – a status report

International Nuclear Information System (INIS)

Drexler, Guido A; Siebenwirth, Christian; Drexler, Sophie E; Girst, Stefanie; Greubel, Christoph; Dollinger, Günther; Friedl, Anna A

2015-01-01

Ion microbeams are important tools in radiobiological research. Still, the worldwide number of ion microbeam facilities where biological experiments can be performed is limited. Even fewer facilities combine ion microirradiation with live-cell imaging to allow microscopic observation of cellular response reactions starting very fast after irradiation and continuing for many hours. At SNAKE, the ion microbeam facility at the Munich 14 MV tandem accelerator, a large variety of biological experiments are performed on a regular basis. Here, recent developments and ongoing research projects at the ion microbeam SNAKE are presented with specific emphasis on live-cell imaging experiments. An overview of the technical details of the setup is given, including examples of suitable biological samples. By ion beam focusing to submicrometer beam spot size and single ion detection it is possible to target subcellular structures with defined numbers of ions. Focusing of high numbers of ions to single spots allows studying the influence of high local damage density on recruitment of damage response proteins. The online version of this article (doi:10.1186/s13014-015-0350-7) contains supplementary material, which is available to authorized users

Laser Raman Spectroscopy with Different Excitation Sources and Extension to Surface Enhanced Raman Spectroscopy

Directory of Open Access Journals (Sweden)

Md. Wahadoszamen

2015-01-01

Full Text Available A dispersive Raman spectrometer was used with three different excitation sources (Argon-ion, He-Ne, and Diode lasers operating at 514.5 nm, 633 nm, and 782 nm, resp.. The system was employed to a variety of Raman active compounds. Many of the compounds exhibit very strong fluorescence while being excited with a laser emitting at UV-VIS region, hereby imposing severe limitation to the detection efficiency of the particular Raman system. The Raman system with variable excitation laser sources provided us with a desired flexibility toward the suppression of unwanted fluorescence signal. With this Raman system, we could detect and specify the different vibrational modes of various hazardous organic compounds and some typical dyes (both fluorescent and nonfluorescent. We then compared those results with the ones reported in literature and found the deviation within the range of ±2 cm−1, which indicates reasonable accuracy and usability of the Raman system. Then, the surface enhancement technique of Raman spectrum was employed to the present system. To this end, we used chemically prepared colloidal suspension of silver nanoparticles as substrate and Rhodamine 6G as probe. We could observe significant enhancement of Raman signal from Rhodamine 6G using the colloidal solution of silver nanoparticles the average magnitude of which is estimated to be 103.

Near-infrared Raman spectroscopy using a diode laser and CCD detector for tissue diagnostics

International Nuclear Information System (INIS)

Gustafsson, U.

1993-09-01

This paper surveys the possibility to observe high-quality NIR Raman spectra of both fluorescent and non-fluorescent samples with the use of a diode laser, a fibre optic sample, a single spectrometer and a charge-coupled device (CCD) detector. A shifted excitation difference technique was implemented for removing the broad-band fluorescence emission from Raman spectra of the highly fluorescent samples. Raman spectra of 1.4-dioxane, toluene, rhodamine 6G, and HITCI in the 640 to 1840 cm -1 spectral region and 1.4-dioxane and toluene in the 400 to 3400 cm -1 spectral region have been recorded. The results open the field of sensitive tissue characterisation and the possibility of optical biopsy in vivo by using NIR Raman spectroscopy with fibre optic sampling, a single spectrometer, and a CCD detector

QUANTITATIVE DETECTION OF ENVIRONMENTALLY IMPORTANT DYES USING DIODE LASER/FIBER-OPTIC RAMAN

Science.gov (United States)

A compact diode laser/fiber-optic Raman spectrometer is used for quantitative detection of environmentally important dyes. This system is based on diode laser excitation at 782 mm, fiber optic probe technology, an imaging spectrometer, and state-of-the-art scientific CCD camera. ...

Confocal Raman microspectroscopy

International Nuclear Information System (INIS)

Puppels, G.J.

1991-01-01

Raman spectroscopy is a technique that provides detailed structural information about molecules studied. In the field of molecular biophysics it has been extensively used for characterization of nucleic acids and proteins and for investigation of interactions between these molecules. It was felt that this technique would have great potential if it could be applied for in situ study of these molecules and their interactions, at the level of single living cell or a chromosome. To make this possible a highly sensitive confocal Raman microspectrometer (CRM) was developed. The instrument is described in detail in this thesis. It incorporates a number of recent technological developments. First, it employs a liquid nitrogen cooled CCD-camera. This type of detector, first used in astronomy, is the ultimate detector for Raman spectroscopy because it combines high quantum efficiency light detection with photon-noise limited operation. Second, an important factor in obtaining a high signal throughput of the spectrometer was the development of a new type of Raman notch filter. In the third place, the confocal detection principle was applied in the CRM. This limits the effective measuring volume to 3 . (author). 279 refs., 48 figs., 11 tabs

Dynamics of a clamped–clamped microbeam resonator considering fabrication imperfections

KAUST Repository

Bataineh, Ahmad M.

2014-10-18

We present an investigation into the static and dynamic behavior of an electrostatically actuated clamped–clamped polysilicon microbeam resonator accounting for its fabrication imperfections, which are commonly encountered in similar microstructures. These are mainly because of the initial deformation of the beam due to stress gradient and its flexible anchors. First, we show experimental data of the microbeam when driven electrically by varying the amplitude and frequency of the voltage loads. The results reveal several interesting nonlinear phenomena of jumps, hysteresis, and softening behaviors. Theoretical investigation is then conducted to model the microbeam, and hence, interpret the experimental data. We solve the Eigen value problem governing the natural frequencies analytically. We then utilize a Galerkin-based procedure to derive a reduced order model, which is then used to simulate both the static and dynamic responses. To achieve good matching between theory and experiment, we show that the exact profile of the deformed beam needs to be utilized in the reduced order model, as measured from the optical profiler, combined with a shooting technique simulation, which is capable of tracing the resonant frequency branches under very-low damping conditions.

Design Considerations for a Portable Raman Probe Spectrometer for Field Forensics

Directory of Open Access Journals (Sweden)

James F. Kelly

2012-01-01

Full Text Available Raman spectroscopy has been shown to be a viable method for explosives detection. Currently most forensic Raman systems are either large, powerful instruments for laboratory experiments or handheld instruments for in situ point detection. We have chosen to examine the performance of certain benchtop Raman probe systems with the goal of developing an inexpensive, portable system that could be used to operate in a field forensics laboratory to examine explosives-related residues or samples. To this end, a rugged, low distortion line imaging dispersive Raman spectrograph was configured to work at 830 nm laser excitation and was used to determine whether the composition of thin films of plastic explosives or small (e.g., ≤10 μm particles of RDX or other explosives or oxidizers can be detected, identified, and quantified in the field. With 300 mW excitation energy, concentrations of RDX and PETN can be detected and reconstructed in the case of thin Semtex smears, but further work is needed to push detection limits of areal dosages to the ~1 μg/cm2 level. We describe the performance of several probe/spectrograph combinations and show preliminary data for particle detection, calibration and detection linearity for mixed compounds, and so forth.

Ultraviolet Raman scattering from persistent chemical warfare agents

Science.gov (United States)

Kullander, Fredrik; Wästerby, Pär.; Landström, Lars

2016-05-01

Laser induced Raman scattering at excitation wavelengths in the middle ultraviolet was examined using a pulsed tunable laser based spectrometer system. Droplets of chemical warfare agents, with a volume of 2 μl, were placed on a silicon surface and irradiated with sequences of laser pulses. The Raman scattering from V-series nerve agents, Tabun (GA) and Mustard gas (HD) was studied with the aim of finding the optimum parameters and the requirements for a detection system. A particular emphasis was put on V-agents that have been previously shown to yield relatively weak Raman scattering in this excitation band.

Micro-beam X-ray fluorescence and absorption imaging techniques at the IAEA Laboratories

International Nuclear Information System (INIS)

Wegrzynek, Dariusz; Markowicz, A.; Bamford, S.; Chinea-Cano, E.; Bogovac, M.

2005-01-01

X-ray tube based, micro-beam X-ray fluorescence scanning spectrometer has been equipped with two energy dispersive X-ray detectors. The two-detector configuration allows for simultaneous collection of X-ray fluorescence (XRF) and transmitted X-ray beam signals with a spatial resolution in the range of 10-50 μm, depending on the X-ray focussing element in use. The XRF signal is collected with a standard, liquid nitrogen cooled Si(Li) detector. The X-ray beam transmitted through the sample is acquired with a thermoelectrically cooled, silicon drift (SD) detector. The data acquisition is carried out in a fully automatic way under control of the SPECTOR-LOCATOR software. The software controls the scanning procedure and X-ray spectra acquisition during the scan. The energy dispersive X-ray spectra collected at every 'pixel' are stored for off-line processing. For selected regions of interest (ROI's), the element maps are constructed and displayed on-line. The spectrometer has been used for mapping elemental distributions and for performing 2D- and 3D-tomograpic imaging of minute objects in X-ray absorption and in X-ray fluorescence mode. A unique feature of the described system is simultaneous utilization of the two detectors, Si(Li) and SD, which adds new options for quantitative analysis and data interpretation. Examples of elemental mapping and 3D tomographic imaging as well as the advanced features of the SPECTOR-LOCATOR measurement control and data acquisition software are presented in this work

Channeling-based collimators for generation of microbeams produced by silicon micromachining technology

International Nuclear Information System (INIS)

Guidi, V.; Antonini, A.; Milan, E.; Ronzoni, A.; Martinelli, G.; Biryukov, V.M.; Chesnokov, Yu.A.

2006-01-01

The growing interest on micro-beams in recent years and the combined development of channeling technology in high-energy physics have opened the way to new concepts for micro-beams devices. Silicon micromachining technology is here applied to manufacture micro-collimators in inexpensive and feasible ways. Both dry and wet etchings can be employed for the purpose, though the latter technique appears to be cheaper and easier. Two designs for micro-collimator devices have been considered and preliminary samples have been produced accordingly

Towards optical fibre based Raman spectroscopy for the detection of surgical site infection

Science.gov (United States)

Thompson, Alex J.; Koziej, Lukasz; Williams, Huw D.; Elson, Daniel S.; Yang, Guang-Zhong

2016-03-01

Surgical site infections (SSIs) are common post-surgical complications that remain significant clinical problems, as they are associated with substantial mortality and morbidity. As such, there is significant interest in the development of minimally invasive techniques that permit early detection of SSIs. To this end, we are applying a compact, clinically deployable Raman spectrometer coupled to an optical fibre probe to the study of bacteria, with the long term goal of using Raman spectroscopy to detect infection in vivo. Our system comprises a 785 nm laser diode for excitation and a commercial (Ocean Optics, Inc.) Raman spectrometer for detection. Here we discuss the design, optimisation and validation of this system, and describe our first experiences interrogating bacterial cells (Escherichia coli) in vitro.

Converse flexoelectric effect in comb electrode piezoelectric microbeam

Energy Technology Data Exchange (ETDEWEB)

Shen, Zhiyuan, E-mail: shenyuan675603@gmail.com [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); Chen, Wei [Microelectronics Centre, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore)

2012-04-09

We demonstrate the converse flexoelectric effect in a lead zirconate titanate microbeam. The fringe electric field of a comb electrode induces converse flexoelectric responses in uniformly poled and depoled beams. The simulated electric field distribution shows that bending of the beam is induced by piezoelectric and μ{sub 11}, μ{sub 12} flexoelectric coefficients. Simulations indicate that piezoelectric displacement occurs in different directions in the two opposite poled samples while flexoelectric displacement remains the same. This finding is verified by the displacement measurement results. -- Highlights: ► We demonstrate the converse flexoelectric effect in a PZT microbeam. ► Beams with upward and downward poling states are fabricated by MEMS technique. ► Converse flexoelectric deformation is induced by the fringe field. ► Electric field distribution is calculated by finite element analysis. ► The simulation results are verified by impedance and displacement measurements.

The Dynamics of a Doubly Clamped Microbeam Near the Primary Resonance: Experimental and Analytical Investigation

KAUST Repository

Masri, Karim M.

2016-01-20

We present experimental and analytical investigation of the dynamics of a doubly clamped microbeam near its primary resonance. The microbeam is excited electrostatically by an electrode on the first half of the beam. These microbeams are fabricated using polyimide as structural layer coated with nickel from top and chromium and gold layers from bottom. A noise signal is applied to experimentally detect the natural frequencies. Then, frequency sweep tests are generated for various values of DC bias revealing hardening, transition, and softening behavior of the microbeam. We report for the first time the transition from lower stable state, to unstable state, and then to large stable state experimentally. A multi-mode Galerkin method is used to develop a reduced order model (ROM) of the beam. Shooting method is used to find the periodic motion and is utilized to generate frequency response curves. The curves show good agreement with the experimental results with hardening behavior at lower DC voltage then softening at higher voltage loads and dynamic pull-in. © Copyright 2015 by ASME.

Study of squeeze film damping in a micro-beam resonator based on micro-polar theory

Directory of Open Access Journals (Sweden)

Mina Ghanbari

Full Text Available In this paper, squeeze film damping in a micro-beam resonator based on micro-polar theory has been investigated. The proposed model for this study consists of a clamped-clamped micro-beam bounded between two fixed layers. The gap between the micro-beam and layers is filled with air. As fluid behaves differently in micro scale than macro, the micro-scale fluid field in the gap has been modeled based on micro-polar theory. Equation of motion governing transverse deflection of the micro- beam based on modified couple stress theory and also non-linear Reynolds equation of the fluid field based on micropolar theory have been non-dimensionalized, linearized and solved simultaneously in order to calculate the quality factor of the resonator. The effect of micropolar parameters of air on the quality factor has been investigated. The quality factor of the of the micro-beam resonator for different values of non-dimensionalized length scale of the beam, squeeze number and also non-dimensionalized pressure has been calculated and compared to the obtained values of quality factor based on classical theory.

Evaluating the peak-to-valley dose ratio of synchrotron microbeams using PRESAGE fluorescence

International Nuclear Information System (INIS)

Annabell, N.; Yagi, N.; Umetani, K.; Wong, C.; Geso, M.

2012-01-01

The peak-to-valley dose ratio of a microbeam array can be measured by fluorescence of PRESAGE dosimeters. Peak-to-valley dose ratios are calculated using this new technique and also by EBT2 film. Synchrotron-generated microbeam radiotherapy holds great promise for future treatment, but the high dose gradients present conventional dosimetry with a challenge. Measuring the important peak-to-valley dose ratio (PVDR) of a microbeam-collimated synchrotron source requires both a dosimeter and an analysis method capable of exceptional spatial resolution. The PVDR is of great interest since it is the limiting factor for potential application of the microbeam radiation therapy technique clinically for its tissue-sparing properties (i.e. the valley dose should be below the tolerance of normal tissue). In this work a new method of measuring the dose response of PRESAGE dosimeters is introduced using the fluorescence from a 638 nm laser on a confocal laser-scanning microscope. This fluorescent microscopy method produces dosimetry data at a pixel size as low as 78 nm, giving a much better spatial resolution than optical computed tomography, which is normally used for scanning PRESAGE dosimeters. Using this technique the PVDR of the BL28B2 microbeam at the SPring-8 synchrotron in Japan is estimated to be approximately 52:1 at a depth of 2.5 mm. The PVDR was also estimated with EBT2 GAFchromic films as 30.5:1 at the surface in order to compare the PRESAGE fluorescent results with a more established dosimetry system. This estimation is in good agreement with previously measured ratios using other dosimeters and Monte Carlo simulations. This means that it is possible to use PRESAGE dosimeters with confocal microscopy for the determination of PVDR

Prospects for in vivo Raman spectroscopy

International Nuclear Information System (INIS)

Hanlon, E.B.; Manoharan, R.; Koo, T.-W.; Shafer, K.E.; Motz, J.T.; Fitzmaurice, M.; Kramer, J.R.; Itzkan, I.; Dasari, R.R.; Feld, M.S.

2000-01-01

Raman spectroscopy is a potentially important clinical tool for real-time diagnosis of disease and in situ evaluation of living tissue. The purpose of this article is to review the biological and physical basis of Raman spectroscopy of tissue, to assess the current status of the field and to explore future directions. The principles of Raman spectroscopy and the molecular level information it provides are explained. An overview of the evolution of Raman spectroscopic techniques in biology and medicine, from early investigations using visible laser excitation to present-day technology based on near-infrared laser excitation and charge-coupled device array detection, is presented. State-of-the-art Raman spectrometer systems for research laboratory and clinical settings are described. Modern methods of multivariate spectral analysis for extracting diagnostic, chemical and morphological information are reviewed. Several in-depth applications are presented to illustrate the methods of collecting, processing and analysing data, as well as the range of medical applications under study. Finally, the issues to be addressed in implementing Raman spectroscopy in various clinical applications, as well as some long-term directions for future study, are discussed. (author)

The ionoluminescence apparatus at the LABEC external microbeam facility

International Nuclear Information System (INIS)

Calusi, S.; Colombo, E.; Giuntini, L.; Giudice, A. Lo; Manfredotti, C.; Massi, M.; Pratesi, G.; Vittone, E.

2008-01-01

In this paper, we describe the main features of the ionoluminescence (IL) apparatus recently installed at the external scanning microbeam facility of the 3 MV Tandetron accelerator of the INFN LABEC Laboratory in Firenze. The peculiarity of this IL set-up resides in the fact that the light produced by the ion irradiation of the specimen is collected by a bifurcated optical fiber, so that photons are shunted both to a CCD spectrometer, working in the 200-900 nm wavelength range, and to a photomultiplier (PMT). The accurate focusing of the optical system allows high photon collection efficiency and this results in rapid acquisition of luminescence spectra with low ion currents on luminescent materials; simultaneously, luminescence maps with a spatial resolution of 10 μm can be acquired through the synchronization of PMT photon detection with the position of the scanning focused ion beam. An optical filter with a narrow passband facing the photomultiplier allows chromatic selectivity of the luminescence centres. The IL apparatus is synergistically integrated into the existing set-up for ion beam analyses (IBA). The upgraded system permits simultaneous IL and PIXE/PIGE/BS measurements. With our integrated system, we have been studying raw lapis lazuli samples of different known origins and precious lapis lazuli artworks of the Collezione Medicea of Museum of Natural History, University of Firenze, aiming at characterising their composition and provenance

The ionoluminescence apparatus at the LABEC external microbeam facility

Energy Technology Data Exchange (ETDEWEB)

Calusi, S.; Colombo, E. [INFN Sezione di Torino, Via P.Giuria 1, 10125 Torino (Italy); Dipartimento di Fisica Sperimentale and NIS Excellence Centre, Universita di Torino, Via P. Giuria 1, 10125 Torino (Italy); Giuntini, L. [Dipartimento di Fisica, Universita and INFN Sezione di Firenze, Via Sansone 1, 50019, Sesto Fiorentino, Firenze (Italy)], E-mail: giuntini@fi.infn.it; Giudice, A. Lo [Dipartimento di Fisica Sperimentale and NIS Excellence Centre, Universita di Torino, Via P. Giuria 1, 10125 Torino (Italy); Manfredotti, C. [INFN Sezione di Torino, Via P.Giuria 1, 10125 Torino (Italy); Dipartimento di Fisica Sperimentale and NIS Excellence Centre, Universita di Torino, Via P. Giuria 1, 10125 Torino (Italy); Massi, M. [Dipartimento di Fisica, Universita and INFN Sezione di Firenze, Via Sansone 1, 50019, Sesto Fiorentino, Firenze (Italy); Pratesi, G. [Dipartimento di Scienze della Terra and Museo di Storia Naturale, Universita di Firenze, Via G. La Pira 4, 50121 Firenze (Italy); Vittone, E. [INFN Sezione di Torino, Via P.Giuria 1, 10125 Torino (Italy); Dipartimento di Fisica Sperimentale and NIS Excellence Centre, Universita di Torino, Via P. Giuria 1, 10125 Torino (Italy)

2008-05-15

In this paper, we describe the main features of the ionoluminescence (IL) apparatus recently installed at the external scanning microbeam facility of the 3 MV Tandetron accelerator of the INFN LABEC Laboratory in Firenze. The peculiarity of this IL set-up resides in the fact that the light produced by the ion irradiation of the specimen is collected by a bifurcated optical fiber, so that photons are shunted both to a CCD spectrometer, working in the 200-900 nm wavelength range, and to a photomultiplier (PMT). The accurate focusing of the optical system allows high photon collection efficiency and this results in rapid acquisition of luminescence spectra with low ion currents on luminescent materials; simultaneously, luminescence maps with a spatial resolution of 10 {mu}m can be acquired through the synchronization of PMT photon detection with the position of the scanning focused ion beam. An optical filter with a narrow passband facing the photomultiplier allows chromatic selectivity of the luminescence centres. The IL apparatus is synergistically integrated into the existing set-up for ion beam analyses (IBA). The upgraded system permits simultaneous IL and PIXE/PIGE/BS measurements. With our integrated system, we have been studying raw lapis lazuli samples of different known origins and precious lapis lazuli artworks of the Collezione Medicea of Museum of Natural History, University of Firenze, aiming at characterising their composition and provenance.

Application of microbeam in bio-science and life science. Biological effects induced in bystander cells by particle microbeams

International Nuclear Information System (INIS)

Suzuki, Masao

2006-01-01

Biological events occurring in cells directly hit by radiation appear in bystander cells nearby not hit directly, which is called the bystander effect. This review describes the events and mechanisms of biological bystander effect yielded by the low-dose radiation including the microbeam. Bystander effects, particularly by charged particle beams, have been studied by two representative approaches by α-ray from plutonium (stochastic irradiation) and by particle microbeams (targeted irradiation), where a bystander effect like chromosome aberrations is shown to occur by communication between irradiated and non-irradiated cells through gap junction. Bystander effects that do not require the cell contact also occur in the irradiated cell-conditioned medium (ICCM), where, not only the short-life radicals like reactive oxygen species and NO, but also more long-life factors participate. Authors have shown the presence of such bystander-inducing factors in ICCM, producing the aberrations even 48 hr after irradiation of either low or high linear energy transfer (LET) radiation. Bystander effects can be important from the aspect of risk assessments of radiation in the terrestrial/spatial environment involving aircraft as well as in cancer therapy by low-dose heavy particle beams. (T.I)

Performances of synchrotron radiation microbeam focused by monolithic half focusing polycapillary X-ray lens

International Nuclear Information System (INIS)

Sun Tianxi; Liu Zhiguo; He Bo; Wei Shiqiang; Xie Yaning; Liu Tao; Hu Tiandou; Ding Xunliang

2007-01-01

A monolithic half focusing polycapillary X-ray lens (MHFPXRL) composed of 289,000 capillaries is used to produce a synchrotron radiation microbeam. The energy dependence of the output focal distance, focal spot size, transmission efficiency, vertical beam position, and gain in flux density of this microbeam is studied in detail. There is a slight change in the output focal distance of the MHFPXRL when the X-ray energies change

Size-dependent pull-in instability of electrostatically actuated microbeam-based MEMS

International Nuclear Information System (INIS)

Wang, Binglei; Zhou, Shenjie; Zhao, Junfeng; Chen, Xi

2011-01-01

We present a size-dependent model for electrostatically actuated microbeam-based MEMS using strain gradient elasticity theory. The normalized pull-in voltage is shown to increase nonlinearly with the decrease of the beam height, and the size effect becomes prominent if the beam thickness is on the order of microns or smaller (i.e. when the beam dimension is comparable to the material length scale parameter). Very good agreement is found between the present model and available experimental data. The study may be helpful to characterize the mechanical properties of small size MEMS, or guide the design of microbeam-based devices for a wide range of potential applications. (technical note)

Microbeams, microdosimetry and specific dose

International Nuclear Information System (INIS)

Randers-Pehrson, H.

2002-01-01

Dose and its usefulness as a single parameter to describe the amount of radiation absorbed are well established for most situations. The conditions where the concept of dose starts to break down are well known, mostly from the study of microdosimetry. For low doses of high LET radiation it is noted that the process of taking the limiting value of the energy absorbed within a test volume divided by the mass within that volume yields either zero or a relatively large value. The problem is further exacerbated with microbeam irradiations where the uniformity of the energy deposition is experimentally manipulated on the spatial scale of cells being irradiated. Booz introduced a quantity to deal with these problems: the unfortunately named 'mean specific energy in affected volumes'. This quantity multiplied by the probability that a test volume has received an energy deposit is equal to dose (in situations where dose can be defined). I propose that Booz's quantity be renamed 'specific dose', that is the mean energy deposited divided by the mass within a specified volume. If we believe for instance that the nucleus of a cell is the critical volume for biological effects, we can refer to the nuclear specific dose. A microbeam experiment wherein 10 per cent of the cell nuclei were targeted with 10 alpha particles would be described as delivering a nuclear specific dose of 1.6 Gy to 10 per cent of the population. (author)

Time-resolved resonance Raman spectroscopy of radiation-chemical processes

International Nuclear Information System (INIS)

Tripathi, G.N.R.

1983-01-01

A tunable pulsed laser Raman spectrometer for time resolved Raman studies of radiation-chemical processes is described. This apparatus utilizes the state of art optical multichannel detection and analysis techniques for data acquisition and electron pulse radiolysis for initiating the reactions. By using this technique the resonance Raman spectra of intermediates with absorption spectra in the 248-900 nm region, and mean lifetimes > 30 ns can be examined. This apparatus can be used to time resolve the vibrational spectral overlap between transients absorbing in the same region, and to follow their decay kinetics by monitoring the well resolved Raman peaks. For kinetic measurements at millisecond time scale, the Raman technique is preferable over optical absorption method where low frequency noise is quite bothersome. A time resolved Raman study of the pulse radiolytic oxidation of aqueous tetrafluorohydroquinone and p-methoxyphenol is briefly discussed. 15 references, 5 figures

On the Nonlinear Dynamics of a Doubly Clamped Microbeam near Primary Resonance

KAUST Repository

Jaber, Nizar; Masri, Karim M.; Younis, Mohammad I.

2017-01-01

This work aims to investigate theoretically and experimentally various nonlinear dynamic behaviors of a doubly clamped microbeam near its primary resonance. Mainly, we investigate the transition behavior from hardening, mixed, and then softening behavior. We show in a single frequency-response curve, under a constant voltage load, the transition from hardening to softening behavior demonstrating the dominance of the quadratic electrostatic nonlinearity over the cubic geometric nonlinearity of the beam as the motion amplitudes becomes large, which may lead eventually to dynamic pull-in. The microbeam is fabricated using polyimide as a structural layer coated with nickel from top and chromium and gold layers from the bottom. Frequency sweep tests are conducted for different values of DC bias revealing hardening, mixed, and softening behavior of the microbeam. A multi-mode Galerkin model combined with a shooting technique are implemented to generate the frequency response curves and to analyze the stability of the periodic motions using the Floquet theory. The simulated curves show good agreement with the experimental data.

On the Nonlinear Dynamics of a Doubly Clamped Microbeam near Primary Resonance

KAUST Repository

Jaber, Nizar

2017-04-07

This work aims to investigate theoretically and experimentally various nonlinear dynamic behaviors of a doubly clamped microbeam near its primary resonance. Mainly, we investigate the transition behavior from hardening, mixed, and then softening behavior. We show in a single frequency-response curve, under a constant voltage load, the transition from hardening to softening behavior demonstrating the dominance of the quadratic electrostatic nonlinearity over the cubic geometric nonlinearity of the beam as the motion amplitudes becomes large, which may lead eventually to dynamic pull-in. The microbeam is fabricated using polyimide as a structural layer coated with nickel from top and chromium and gold layers from the bottom. Frequency sweep tests are conducted for different values of DC bias revealing hardening, mixed, and softening behavior of the microbeam. A multi-mode Galerkin model combined with a shooting technique are implemented to generate the frequency response curves and to analyze the stability of the periodic motions using the Floquet theory. The simulated curves show good agreement with the experimental data.

Microbeam high-resolution diffraction and x-ray standing wave methods applied to semiconductor structures

International Nuclear Information System (INIS)

Kazimirov, A; Bilderback, D H; Huang, R; Sirenko, A; Ougazzaden, A

2004-01-01

A new approach to conditioning x-ray microbeams for high angular resolution x-ray diffraction and scattering techniques is introduced. We combined focusing optics (one-bounce imaging capillary) and post-focusing collimating optics (miniature Si(004) channel-cut crystal) to generate an x-ray microbeam with a size of 10 μm and ultimate angular resolution of 14 μrad. The microbeam was used to analyse the strain in sub-micron thick InGaAsP epitaxial layers grown on an InP(100) substrate by the selective area growth technique in narrow openings between the oxide stripes. For the structures for which the diffraction peaks from the substrate and the film overlap, the x-ray standing wave technique was applied for precise measurements of the strain with a Δd/d resolution of better than 10 -4 . (rapid communication)

FT-IR, RAMAN AND DFT STUDIES ON THE VIBRATIONAL ...

African Journals Online (AJOL)

Department of Physics, Science Faculty, Anadolu University, Eskişehir, Turkey ... IR spectrum was recorded using Bruker Optics IFS66v/s FTIR spectrometer at a ... spectrum was obtained using a Bruker Senterra Dispersive Raman microscope.

An Experimental and Theoretical Investigation of Electrostatically Coupled Cantilever Microbeams

KAUST Repository

Ilyas, Saad; Chappanda, Karumbaiah N.; Hafiz, Md Abdullah Al; Ramini, Abdallah; Younis, Mohammad I.

2016-01-01

We present an experimental and theoretical investigation of the static and dynamic behavior of electrostatically coupled laterally actuated silicon microbeams. The coupled beam resonators are composed of two almost identical flexible cantilever

Monte Carlo dose calculation of microbeam in a lung phantom

International Nuclear Information System (INIS)

Company, F.Z.; Mino, C.; Mino, F.

1998-01-01

Full text: Recent advances in synchrotron generated X-ray beams with high fluence rate permit investigation of the application of an array of closely spaced, parallel or converging microplanar beams in radiotherapy. The proposed techniques takes advantage of the hypothesised repair mechanism of capillary cells between alternate microbeam zones, which regenerates the lethally irradiated endothelial cells. The lateral and depth doses of 100 keV microplanar beams are investigated for different beam dimensions and spacings in a tissue, lung and tissue/lung/tissue phantom. The EGS4 Monte Carlo code is used to calculate dose profiles at different depth and bundles of beams (up to 20x20cm square cross section). The maximum dose on the beam axis (peak) and the minimum interbeam dose (valley) are compared at different depths, bundles, heights, widths and beam spacings. Relatively high peak to valley ratios are observed in the lung region, suggesting an ideal environment for microbeam radiotherapy. For a single field, the ratio at the tissue/lung interface will set the maximum dose to the target volume. However, in clinical application, several fields would be involved allowing much greater doses to be applied for the elimination of cancer cells. We conclude therefore that multifield microbeam therapy has the potential to achieve useful therapeutic ratios for the treatment of lung cancer

Memory and survival after microbeam radiation therapy

International Nuclear Information System (INIS)

Schueltke, Elisabeth; Juurlink, Bernhard H.J.; Ataelmannan, Khalid; Laissue, Jean; Blattmann, Hans; Braeuer-Krisch, Elke; Bravin, Alberto; Minczewska, Joanna; Crosbie, Jeffrey; Taherian, Hadi; Frangou, Evan; Wysokinsky, Tomasz; Chapman, L. Dean; Griebel, Robert; Fourney, Daryl

2008-01-01

Background: Disturbances of memory function are frequently observed in patients with malignant brain tumours and as adverse effects after radiotherapy to the brain. Experiments in small animal models of malignant brain tumour using synchrotron-based microbeam radiation therapy (MRT) have shown a promising prolongation of survival times. Materials and methods: Two animal models of malignant brain tumour were used to study survival and memory development after MRT. Thirteen days after implantation of tumour cells, animals were submitted to MRT either with or without adjuvant therapy (buthionine-SR-sulfoximine = BSO or glutamine). We used two orthogonal 1-cm wide arrays of 50 microplanar quasiparallel microbeams of 25 μm width and a center-to-center distance of about 200 μm, created by a multislit collimator, with a skin entrance dose of 350 Gy for each direction. Object recognition tests were performed at day 13 after tumour cell implantation and in monthly intervals up to 1 year after tumour cell implantation. Results: In both animal models, MRT with and without adjuvant therapy significantly increased survival times. BSO had detrimental effects on memory function early after therapy, while administration of glutamine resulted in improved memory

Role of Raman spectroscopy and surface enhanced Raman spectroscopy in colorectal cancer

Science.gov (United States)

Jenkins, Cerys A; Lewis, Paul D; Dunstan, Peter R; Harris, Dean A

2016-01-01

Colorectal cancer (CRC) is the fourth most common cancer in the United Kingdom and is the second largest cause of cancer related death in the United Kingdom after lung cancer. Currently in the United Kingdom there is not a diagnostic test that has sufficient differentiation between patients with cancer and those without cancer so the current referral system relies on symptomatic presentation in a primary care setting. Raman spectroscopy and surface enhanced Raman spectroscopy (SERS) are forms of vibrational spectroscopy that offer a non-destructive method to gain molecular information about biological samples. The techniques offer a wide range of applications from in vivo or in vitro diagnostics using endoscopic probes, to the use of micro-spectrometers for analysis of biofluids. The techniques have the potential to detect molecular changes prior to any morphological changes occurring in the tissue and therefore could offer many possibilities to aid the detection of CRC. The purpose of this review is to look at the current state of diagnostic technology in the United Kingdom. The development of Raman spectroscopy and SERS in clinical applications relation for CRC will then be discussed. Finally, future areas of research of Raman/SERS as a clinical tool for the diagnosis of CRC are also discussed. PMID:27190582

Using Raman spectroscopic imaging for non-destructive analysis of filler distribution in chalk filled polypropylene

DEFF Research Database (Denmark)

Boros, Evelin; Porse, Peter Bak; Nielsen, Inga

2016-01-01

A feasibility study on using Raman spectral imaging for visualization and analysis of filler distribution in chalk filled poly-propylene samples has been carried out. The spectral images were acquired using a Raman spectrometer with 785 nm light source.Eight injection-molded samples with concentr...

Online imaging of initial DNA damages at the PTB microbeam

International Nuclear Information System (INIS)

Giesen, U.; Langner, F.; Mielke, C.; Mosconi, M.; Dirks, W. G.

2011-01-01

In an inter-disciplinary collaboration of Physikalisch-Technische Bundesanstalt (PTB), German Collection of Microorganisms and Cell Cultures (DSMZ) and Heinrich-Heine Univ., live-cell imaging has been established at the charged-particle microbeam facility of PTB. Candidate genes participating in DNA strand-break repair pathways such as PARP-1, MRE11, MSH2, MDC1 and p53BP1 have been modified to generate fluorescent fusion proteins. Using multi-cistronic expression vectors, stable genomic integration was achieved in HT-1080 fibroblasts. The aim of this study is to characterise and use these highly reliable cell lines for studying initial steps of DNA damage responses and kinetics of repair after microbeam irradiation with high- and low-linear energy transfer (LET) particles in living cells at physiological conditions. (authors)

Synchrotron microbeam irradiation induces neutrophil infiltration, thrombocyte attachment and selective vascular damage in vivo

OpenAIRE

Br?nnimann, Daniel; Bouchet, Audrey; Schneider, Christoph; Potez, Marine; Serduc, Rapha?l; Br?uer-Krisch, Elke; Graber, Werner; von Gunten, Stephan; Laissue, Jean Albert; Djonov, Valentin

2016-01-01

International audience; Our goal was the visualizing the vascular damage and acute inflammatory response to micro-and minibeam irradiation in vivo. Microbeam (MRT) and minibeam radiation therapies (MBRT) are tumor treatment approaches of potential clinical relevance, both consisting of parallel X-ray beams and allowing the delivery of thousands of Grays within tumors. We compared the effects of microbeams (25– 100 μm wide) and minibeams (200–800 μm wide) on vasculature, inflammation and surro...

An Empirical Study on Raman Peak Fitting and Its Application to Raman Quantitative Research.

Science.gov (United States)

Yuan, Xueyin; Mayanovic, Robert A

2017-10-01

Fitting experimentally measured Raman bands with theoretical model profiles is the basic operation for numerical determination of Raman peak parameters. In order to investigate the effects of peak modeling using various algorithms on peak fitting results, the representative Raman bands of mineral crystals, glass, fluids as well as the emission lines from a fluorescent lamp, some of which were measured under ambient light whereas others under elevated pressure and temperature conditions, were fitted using Gaussian, Lorentzian, Gaussian-Lorentzian, Voigtian, Pearson type IV, and beta profiles. From the fitting results of the Raman bands investigated in this study, the fitted peak position, intensity, area and full width at half-maximum (FWHM) values of the measured Raman bands can vary significantly depending upon which peak profile function is used in the fitting, and the most appropriate fitting profile should be selected depending upon the nature of the Raman bands. Specifically, the symmetric Raman bands of mineral crystals and non-aqueous fluids are best fit using Gaussian-Lorentzian or Voigtian profiles, whereas the asymmetric Raman bands are best fit using Pearson type IV profiles. The asymmetric O-H stretching vibrations of H 2 O and the Raman bands of soda-lime glass are best fit using several Gaussian profiles, whereas the emission lines from a florescent light are best fit using beta profiles. Multiple peaks that are not clearly separated can be fit simultaneously, provided the residuals in the fitting of one peak will not affect the fitting of the remaining peaks to a significant degree. Once the resolution of the Raman spectrometer has been properly accounted for, our findings show that the precision in peak position and intensity can be improved significantly by fitting the measured Raman peaks with appropriate profiles. Nevertheless, significant errors in peak position and intensity were still observed in the results from fitting of weak and wide Raman

Nonlinear behavior of capacitive micro-beams based on strain gradient theory

International Nuclear Information System (INIS)

Fathalilou, Mohammad; Sadeghi, Morteza; Rezazadeh, Ghader

2014-01-01

This paper studies the size dependent behavior of materials in MEMS structures. This behavior becomes noticeable for a structure when the characteristic size such as thickness or diameter is close to its internal length-scale parameter and is insignificant for the high ratio of the characteristic size to the length-scale parameter, which is the case of the silicon base micro-beams. However, in some types of micro-beams like gold or nickel bases, the size dependent effect cannot be overlooked. In such cases, ignoring this behavior in modeling will lead to incorrect results. Some previous researchers have applied classic beam theory on their models and imposed a considerable hypothetical value of residual stress to match their theoretical results with the experimental ones. The equilibrium positions or fixed points of the gold and nickel micro-beams are obtained and shown that for a given DC voltage, there is a considerable difference between the obtained fixed points using classic beam theory, modified couple stress theory, and modified strain gradient theory. In addition, it is shown that the calculated static and dynamic pull-in voltages using higher order theories are much closer to the experimental results and are higher several times than those obtained by classic beam theory.

Heavy Ion Microbeam and Broadbeam Transients in SiGe HBTs

Science.gov (United States)

Pellish, Jonathan A.; Reed, Robert A.; McMorrow, Dale; Vizkelethy, Gyorgy; Dodd, Paul E.; Ferlet-Cavrois, Veronique; Baggio, Jacques; Paillet, Philippe; Duhamel, Olivier; Phillips, Stanley D.;

Silver nanoplate-decorated copper wire for the on-site microextraction and detection of perchlorate using a portable Raman spectrometer.

Science.gov (United States)

Zhu, Sha; Zhang, Xiaoli; Cui, Jingcheng; Shi, Yu-E; Jiang, Xiaohong; Liu, Zhen; Zhan, Jinhua

2015-04-21

Perchlorate, which causes health concerns because of its effects on the thyroid function, is highly soluble and mobile in the environment. In this study, diethyldithiocarbamate (DDTC)-modified silver nanoplates were fabricated on a copper wire to perform the on-site microextraction and detection of perchlorate. This fiber could be inserted into water or soil to extract perchlorate through electrostatic interaction and then can be detected by a portable Raman spectrometer, owing to its surface-enhanced Raman (SERS) activity. A relatively stable vibrational mode (δ(HCH)(CH3), (CH2)) of DDTC at 1273 cm(-1) was used as an internal standard, which was negligibly influenced by the absorption of ClO4(-). The DDTC-modified Ag/Cu fiber showed high uniformity, good reusability and temporal stability under continuous laser radiation each with an RSD lower than 10%. The qualitative and quantitative detection of perchlorate were also realized. A log-log plot of the normalized SERS intensity against perchlorate concentration showed a good linear relationship. The fiber could be also directly inserted into the perchlorate-polluted soil, and the perchlorate could thereby be detected on site. The detection limit in soil reached 0.081 ppm, which was much lower than the EPA-published safety standard. The recovery of the detection was 105% and comparable with the ion chromatography. This hyphenated method of microextraction with direct SERS detection may find potential application for direct pollutant detection free from complex sample pretreatment.

Influence of squeeze film damping on the higher-order modes of clamped–clamped microbeams

KAUST Repository

Alcheikh, Nouha

2016-05-06

This paper presents an experimental study and a finite-element analysis of the effect of squeeze film damping on the resonance frequency and quality factor of the higher-order flexure vibrations modes of clamped-clamped microbeams. Viscoelastic and silicon nitride microbeams are fabricated and are electrostatically actuated by various electrode configurations to trigger the first, second, and third modes. The damping characteristic and the resonance frequency of these modes are examined for a wide range of gas pressure and electrostatic voltage loads. The results of the silicon nitride beams and viscoelastic beams are compared. It is found that the intrinsic material loss is the major dissipation mechanism at low pressure for the viscoelastic microbeams, significantly limiting their quality factor. It is also found that while the silicon nitride beams show higher quality factors at the intrinsic and molecular regimes of pressure, due to their low intrinsic loss, their quality factors near atmospheric pressure are lower than those of the viscoelastic microbeams. Further, the higher-order modes of all the beams show much higher quality factors at atmospheric pressure compared to the first mode, which could be promising for operating such resonators in air. Experimental results and finite element model simulations show good agreement for resonance frequency and quality factor for the three studied modes. © 2016 IOP Publishing Ltd.

Diagnosis of spatial resolution for microbeam scanning PIXE using STIM method and CR-39 track detector in PASTA

International Nuclear Information System (INIS)

Hamano, T.; Imaseki, H.; Yukawa, M.; Ishikawa, T.; Iso, H.; Matsumoto, K.

2003-01-01

In PIXE analysis system and Tandem Accelerator facility (PASTA) of NIRS, we are using Scanning Transmission Ion Microscopy (STIM) method and solid track detector to diagnose the spatial resolution of scanning microbeam PIXE analysis system. These methods are widely used by many microbeam facilities. (author)

Operation manual of microbeam system in Takasaki for biological application (MiST-BA)

International Nuclear Information System (INIS)

Sakashita, Tetsuya; Yokota, Yuichiro; Wada, Seiichi; Funayama, Tomoo; Kobayashi, Yasuhiko

2004-03-01

Microbeam System is a powerful tool for micro-radiosurgery studies and direct investigation of cell-to-cell communications such as 'bystander effects'. Microbeam system in Takasaki for biological application (MiST-BA) has been developed for several years and applied to some cases. There were fate mapping of the cellular blastoderm stage egg of the silkworm and bystander effects such as inhibition of cell proliferation, induction of micronuclei, and so on. The aim of this report (operation manual) is to provide a simple and easy usage of MiST-BA for current and new users. MiST-BA consists of three parts; (1) Offline microscope control system for cell-finding. (2) Online microscope control system for cell-targeting and irradiating, and (3) Beam shutter control system for cell irradiation with a precise number of heavy ions. The report presents the outline of MiST-BA, the operation protocol of each part, examples of a microbeam irradiation experiment using CHO-K1 cells, silkworm eggs, and Tobacco protoplast cells, and Trouble shooting. (author)

Determination of chemical composition of individual airborne particles by SEM/EDX and micro-Raman spectrometry: A review

International Nuclear Information System (INIS)

Stefaniak, E A; Buczynska, A; Novakovic, V; Van Grieken, R; Kuduk, R

2009-01-01

The strategies for sampling and analysis by SEM/EDX and micro-Raman spectrometry for individual airborne particles analysis as applied at the University of Antwerp (Belgium) by the MITAC group have been reviewed. Microbeam techniques provide detailed information concerning the origin, formation, transport, reactivity, transformation reactions and environmental impact of particulate matter. Moreover, some particles of certain chemical properties have been recognized as a threat for human health and cultural heritage objects. However, the small sizes of particles result in specific problems with respect to single particle analysis. Development of equipment and software for improvement of analysis and quantification are reported.

Raman vibrational spectra of thymol blue dyed polyvinyl alcohol (PVA) film dosimeters

International Nuclear Information System (INIS)

Lepit, A.; Saion, E.B.; Susilawati; Doyan, A.; Wan Yusoff, W.M.D.

2002-01-01

Radiation-sensitive dyed polyvinyl alcohol (PVA) film indicators containing chloral hydrate and acid-sensitive thymol blue dye have been studied for routine food irradiation dosimeters. The free standing dyed film dosimeters of different chloral hydrate concentrations (0.1, 0.5, 1.0, 2.0 and 2.5 g) were irradiated with the absorbed dose ranges from 1 kGy to 12 kGy using gamma rays from Co-60 teletherapy. Upon exposure the dosimeters undergo chemical change and become more acidic, resulting in colour change from yellow to red at the critical doses depending on the chloral hydrate concentrations. The radiation-induced change in colour was analysed using UV-Vis spectrometer that the absorption spectra produced two maximal of the visible bands peaking at 445 nm for low doses and 554 nm for high doses. Spectra of inelastic Raman scattering photons corresponding to Raman shift frequency of unirradiated and irradiated films were measured using a dispersive Raman spectrometer. The spectral intensity of C=C, C-0 and S-H molecular vibration peaks for their respective Raman shifts were studied which provide the dose response to the change of dye molecular structure of the dosimeters. (Author)

Optimizing laser crater enhanced Raman spectroscopy.

Science.gov (United States)

Lednev, V N; Sdvizhenskii, P A; Grishin, M Ya; Filichkina, V A; Shchegolikhin, A N; Pershin, S M

2018-03-20

Raman signal enhancement by laser crater production was systematically studied for 785 nm continuous wave laser pumping. Laser craters were produced in L-aspartic acid powder by a nanosecond pulsed solid state neodymium-doped yttrium aluminum garnet laser (532 nm, 8 ns, 1 mJ/pulse), while Raman spectra were then acquired by using a commercial spectrometer with 785 nm laser beam pumping. The Raman signal enhancement effect was studied in terms of the number of ablating pulses used, the lens-to-sample distance, and the crater-center-laser-spot offset. The influence of the experiment parameters on Raman signal enhancement was studied for different powder materials. Maximum Raman signal enhancement reached 11 fold for loose powders but decreased twice for pressed tablets. Raman signal enhancement was demonstrated for several diverse powder materials like gypsum or ammonium nitrate with better results achieved for the samples tending to give narrow and deep craters upon the laser ablation stage. Alternative ways of cavity production (steel needle tapping and hole drilling) were compared with the laser cratering technique in terms of Raman signal enhancement. Drilling was found to give the poorest enhancement of the Raman signal, while both laser ablation and steel needle tapping provided comparable results. Here, we have demonstrated for the first time, to the best of our knowledge, that a Raman signal can be enhanced 10 fold with the aid of simple cavity production by steel needle tapping in rough highly reflective materials. Though laser crater enhancement Raman spectroscopy requires an additional pulsed laser, this technique is more appropriate for automatization compared to the needle tapping approach.

A portable Raman acoustic levitation spectroscopic system for the identification and environmental monitoring of algal cells.

Science.gov (United States)

Wood, Bayden R; Heraud, Philip; Stojkovic, Slobodanka; Morrison, Danielle; Beardall, John; McNaughton, Don

2005-08-01

We report the coupling of a portable Raman spectrometer to an acoustic levitation device to enable environmental monitoring and the potential taxonomic identification of microalgae. Spectra of living cells were recorded at 785 nm using a fiber-optic probe coupled to a portable Raman spectrometer. The spectra exhibit an excellent signal-to-noise ratio and clearly show bands from chlorophyll a and beta-carotene. Spectra of levitated photobleached microalgae clearly show a reduction in chlorophyll a concentration relative to beta-carotene after 10 min of exposure to a quartz halogen lamp. Spectra recorded from levitated nitrogen-limited cells also show a significant reduction in bands associated with chlorophyll a, as compared to nitrogen-replete cells. To investigate the diagnostic capability of the technique, four species of microalgae were analyzed. Good quality spectra of all four species were obtained showing varying ratios of beta-carotene to chlorophyll. The combination of an acoustic levitation device and a portable Raman spectrometer shows potential as a taxonomic and environmental monitoring tool with direct application to field studies in remote environments.

A new on-axis multimode spectrometer for the macromolecular crystallography beamlines of the Swiss Light Source

International Nuclear Information System (INIS)

Owen, Robin L.; Pearson, Arwen R.; Meents, Alke; Boehler, Pirmin; Thominet, Vincent; Schulze-Briese, Clemens

2009-01-01

Complementary techniques greatly aid the interpretation of macromolecule structures to yield functional information, and can also help to track radiation-induced changes. A new on-axis spectrometer being integrated into the macromolecular crystallography beamlines of the Swiss Light Source is presented. X-ray crystallography at third-generation synchrotron sources permits tremendous insight into the three-dimensional structure of macromolecules. Additional information is, however, often required to aid the transition from structure to function. In situ spectroscopic methods such as UV–Vis absorption and (resonance) Raman can provide this, and can also provide a means of detecting X-ray-induced changes. Here, preliminary results are introduced from an on-axis UV–Vis absorption and Raman multimode spectrometer currently being integrated into the beamline environment at X10SA of the Swiss Light Source. The continuing development of the spectrometer is also outlined

Application of heavy-ion microbeam system at Kyoto University: Energy response for imaging plate by single ion irradiation

International Nuclear Information System (INIS)

Tosaki, M.; Nakamura, M.; Hirose, M.; Matsumoto, H.

2011-01-01

A heavy-ion microbeam system for cell irradiation has been developed using an accelerator at Kyoto University. We have successfully developed proton-, carbon-, fluorine- and silicon-beams in order to irradiate a micro-meter sized area with ion counting, especially single ion irradiation. In the heavy-ion microbeam system, an imaging plate (IP) was utilized for beam diagnostics on the irradiation. The IP is widely used for radiography studies in biology. However, there are a few studies on the low linear energy transfer (LET) by single ions, i.e., low-intensity exposure. Thus we have investigated the energy response for the IP, which can be utilized for microbeam diagnostics.

Raman tweezers spectroscopy of live, single red and white blood cells.

Directory of Open Access Journals (Sweden)

Aseefhali Bankapur

Full Text Available An optical trap has been combined with a Raman spectrometer to make high-resolution measurements of Raman spectra of optically-immobilized, single, live red (RBC and white blood cells (WBC under physiological conditions. Tightly-focused, near infrared wavelength light (1064 nm is utilized for trapping of single cells and 785 nm light is used for Raman excitation at low levels of incident power (few mW. Raman spectra of RBC recorded using this high-sensitivity, dual-wavelength apparatus has enabled identification of several additional lines; the hitherto-unreported lines originate purely from hemoglobin molecules. Raman spectra of single granulocytes and lymphocytes are interpreted on the basis of standard protein and nucleic acid vibrational spectroscopy data. The richness of the measured spectrum illustrates that Raman studies of live cells in suspension are more informative than conventional micro-Raman studies where the cells are chemically bound to a glass cover slip.

Neurocognitive sparing of desktop microbeam irradiation.

Science.gov (United States)

Bazyar, Soha; Inscoe, Christina R; Benefield, Thad; Zhang, Lei; Lu, Jianping; Zhou, Otto; Lee, Yueh Z

2017-08-11

Normal tissue toxicity is the dose-limiting side effect of radiotherapy. Spatial fractionation irradiation techniques, like microbeam radiotherapy (MRT), have shown promising results in sparing the normal brain tissue. Most MRT studies have been conducted at synchrotron facilities. With the aim to make this promising treatment more available, we have built the first desktop image-guided MRT device based on carbon nanotube x-ray technology. In the current study, our purpose was to evaluate the effects of MRT on the rodent normal brain tissue using our device and compare it with the effect of the integrated equivalent homogenous dose. Twenty-four, 8-week-old male C57BL/6 J mice were randomly assigned to three groups: MRT, broad-beam (BB) and sham. The hippocampal region was irradiated with two parallel microbeams in the MRT group (beam width = 300 μm, center-to-center = 900 μm, 160 kVp). The BB group received the equivalent integral dose in the same area of their brain. Rotarod, marble burying and open-field activity tests were done pre- and every month post-irradiation up until 8 months to evaluate the cognitive changes and potential irradiation side effects on normal brain tissue. The open-field activity test was substituted by Barnes maze test at 8th month. A multilevel model, random coefficients approach was used to evaluate the longitudinal and temporal differences among treatment groups. We found significant differences between BB group as compared to the microbeam-treated and sham mice in the number of buried marble and duration of the locomotion around the open-field arena than shams. Barnes maze revealed that BB mice had a lower capacity for spatial learning than MRT and shams. Mice in the BB group tend to gain weight at the slower pace than shams. No meaningful differences were found between MRT and sham up until 8-month follow-up using our measurements. Applying MRT with our newly developed prototype compact CNT-based image-guided MRT system

High-throughput spectrometer designs in a compact form-factor: principles and applications

Science.gov (United States)

Norton, S. M.

2013-05-01

Many compact, portable Raman spectrometers have entered the market in the past few years with applications in narcotics and hazardous material identification, as well as verification applications in pharmaceuticals and security screening. Often, the required compact form-factor has forced designers to sacrifice throughput and sensitivity for portability and low-cost. We will show that a volume phase holographic (VPH)-based spectrometer design can achieve superior throughput and thus sensitivity over conventional Czerny-Turner reflective designs. We will look in depth at the factors influencing throughput and sensitivity and illustrate specific VPH-based spectrometer examples that highlight these design principles.

Development of the Jyvaeskylae microbeam facility

Energy Technology Data Exchange (ETDEWEB)

Norarat, Rattanaporn, E-mail: rattanaporn.norarat@phys.jyu.fi [Department of Physics, University of Jyvaeskylae, P.O. Box 35 (YFL), FIN-40014 Jyvaeskylae (Finland); Sajavaara, Timo; Laitinen, Mikko; Heikkinen, Pauli; Ranttila, Kimmo; Ylikorkala, Kari; Haenninen, Vaeinoe; Rossi, Mikko; Jones, Pete [Department of Physics, University of Jyvaeskylae, P.O. Box 35 (YFL), FIN-40014 Jyvaeskylae (Finland); Marjomaeki, Varpu; Gilbert, Leona [Department of Environmental and Biological Sciences, University of Jyvaeskylae, P.O. Box 35 (YFL), FIN-40014 Jyvaeskylae (Finland); Whitlow, Harry J. [Department of Physics, University of Jyvaeskylae, P.O. Box 35 (YFL), FIN-40014 Jyvaeskylae (Finland)

2012-02-01

Research highlights: Black-Right-Pointing-Pointer A MeV ion microbeam for biomedical materials research is being developed. Black-Right-Pointing-Pointer High accuracy scanning using electrostatic post-focus deflection. Black-Right-Pointing-Pointer Imaging and direct lithographic image writing using time-stamping methods. Black-Right-Pointing-Pointer New scanning modes and fluorescence detectors permit low ion-fluence cell imaging. Black-Right-Pointing-Pointer Thermal compensated beam-line support design for high positional accuracy. - Abstract: A new microbeam facility is being constructed at the 1.7 MV Pelletron Accelerator in Jyvaeskylae. The facility is designed for easy upgrading and incorporates a number of innovative features. Initially, it is based on a Heidelberg doublet with a design capability of a 3 Multiplication-Sign 5 {mu}m beamspot at PIXE intensities and later upgraded to nanobeam performance. A thermal-expansion compensated rigid frame mounted on a mechanically isolated floor section is used to support the ion optical components. A compact-post focusing electrostatic deflector is used for high linearity beam scanning. This together with a novel time-stamped data collection (TDC) allows dynamic effects in IBIC, fluorescence bleaching to be studied as well as facilitating multi-resolution image support for low-fluence imaging of cells. The target chamber is fitted with a novel low-cost large working distance optical microscope, extremely compact large solid angle photon detectors as well as conventional secondary electron, PIXE and Scanning Transmission Ion Microscopy (STIM) detectors.

Piezoelectric transduction of flexural modes in pre-stressed microbeam resonators

NARCIS (Netherlands)

Torri, G.B.; Janssen, N.M.A.; Zeng, Z.; Rottenberg, X.; Karabacak, D.M.; Vandecasteele, M.; Hoof, C.V.; Puers, R.; Tilmans, H.A.C.

2014-01-01

This paper reports on the optimization of the design of piezoelectric transducer elements integrated on doubly-clamped microbeam resonators utilized as (bio)chemical sensors. We report and emphasize the often forgotten influence of membrane stresses on defining the dimensions and optimal position of

Development of economic MeV-ion microbeam technology at Chiang Mai University

Science.gov (United States)

Singkarat, S.; Puttaraksa, N.; Unai, S.; Yu, L. D.; Singkarat, K.; Pussadee, N.; Whitlow, H. J.; Natyanum, S.; Tippawan, U.

2017-08-01

Developing high technologies but in economic manners is necessary and also feasible for developing countries. At Chiang Mai University, Thailand, we have developed MeV-ion microbeam technology based on a 1.7-MV Tandetron tandem accelerator with our limited resources in a cost-effective manner. Instead of using expensive and technically complex electrostatic or magnetic quadrupole focusing lens systems, we have developed cheap MeV-ion microbeams using programmed L-shaped blade aperture and capillary techniques for MeV ion beam lithography or writing and mapping. The programmed L-shaped blade micro-aperture system consists of a pair of L-shaped movable aperture pieces which are controlled by computer to cut off the ion beam for controlling the beam size down to the micrometer order. The capillary technique utilizes our home-fabricated tapered glass capillaries to realize microbeams. Either system can be installed inside the endstation of the MeV ion beam line of the accelerator. Both systems have been applied to MeV-ion beam lithography or writing of micro-patterns for microfluidics applications to fabricate lab-on-chip devices. The capillary technique is being developed for MeV-ion beam mapping of biological samples. The paper reports details of the techniques and introduces some applications.

Purchase of a Raman and Photoluminescence Imaging System for Characterization of Advanced Electrochemical and Electronic Materials

Science.gov (United States)

2016-01-05

SECURITY CLASSIFICATION OF: Funds were used to purchase a Renishaw inVia Reflex Spectrometer System for Raman and Photoluminescence spectral...Unlimited UU UU UU UU 05-01-2016 15-Aug-2014 14-Aug-2015 Final Report: Purchase of a Raman and Photoluminescence Imaging System for Characterization of...MONITORING AGENCY NAME(S) AND ADDRESS (ES) U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 Raman spectroscopy

Weanling piglet cerebellum: a surrogate for tolerance to MRT (microbeam radiation therapy) in pediatric neuro-oncology

Science.gov (United States)

Laissue, Jean A.; Blattmann, Hans; Di Michiel, Marco; Slatkin, Daniel N.; Lyubimova, Nadia; Guzman, Raphael; Zimmermann, Werner; Birrer, Stephan; Bley, Tim; Kircher, Patrick; Stettler, Regina; Fatzer, Rosmarie; Jaggy, Andre; Smilowitz, Henry; Brauer, Elke; Bravin, Alberto; Le Duc, Geraldine; Nemoz, Christian; Renier, Michel; Thomlinson, William C.; Stepanek, Jiri; Wagner, Hans-Peter

2001-12-01

The cerebellum of the weanling piglet (Yorkshire) was used as a surrogate for the radiosensitive human infant cerebellum in a Swiss-led program of experimental microbeam radiation therapy (MRT) at the ESRF. Five weanlings in a 47 day old litter of seven, and eight weanlings in a 40 day old litter of eleven were irradiated in November, 1999 and June, 2000, respectively. A 1.5 cm-wide x 1.5 xm-high array of equally space approximately equals 20-30 micrometers wide, upright microbeams spaced at 210 micrometers intervals was propagated horizontally, left to right, through the cerebella of the prone, anesthetized piglets. Skin-entrance intra-microbeam peak adsorbed doses were uniform, either 150, 300, 425, or 600 gray (Gy). Peak and inter-microbeam (valley) absorbed doses in the cerebellum were computed with the PSI version of the Monte Carlo code GEANT and benchmarked using Gafchromic and radiochromic film microdosimetry. For approximately equals 66 weeks [first litter; until euthanasia], or approximately equals 57 weeks [second litter; until July 30, 2001] after irradiation, the littermates were developmentally, behaviorally, neurologically and radiologically normal as observed and tested by experienced farmers and veterinary scientists unaware of which piglets were irradiated or sham-irradiated. Morever, MRT implemented at the ESRF with a similar array of microbeams and a uniform skin-entrance peak dose of 625 Gy, followed by immunoprophylaxis, was shown to be palliative or curative in young adult rats bearing intracerebral gliosarcomas. These observations give further credence to MRT's potential as an adjunct therapy for brain tumors in infancy, when seamless therapeutic irradiation of the brain is hazardous.

Development of a Charged Particle Microbeam for Single-Particle Subcellular Irradiations at the MIT Laboratory for Accelerator Beam Application

International Nuclear Information System (INIS)

Yanch, Jacquelyn C.

2004-01-01

The development of a charged particle microbeam for single particle, subcellular irradiations at the Massachusetts Institute of Technology Laboratory for Accelerator Beam Applications (MIT LABA) was initiated under this NEER aeard. The Microbeam apparatus makes use of a pre-existing electrostatic accelerator with a horizontal beam tube

A new paradigm in radioadaptive response developing from microbeam research

International Nuclear Information System (INIS)

Matsumoto, Hideki; Tomita, Masanori; Otsuka, Kensuke; Hatashita, Masanori

2009-01-01

A classic paradigm in radiation biology asserts that all radiation effects on cells, tissues and organisms are due to the direct action of radiation on living tissue. Using this model, possible risks from exposure to low dose ionizing radiation (below 100 mSv) are estimated by extrapolating from data obtained after exposure to higher doses of radiation, using a linear non-threshold model (LNT model). However, the validity of using this dose-response model is controversial because evidence accumulated over the past decade has indicated that living organisms, including humans, respond differently to low dose/low dose-rate radiation than they do to high dose/high dose-rate radiation. These important responses to low dose/low dose-rate radiation are the radiation-induced adaptive response, the bystander response, low-dose hypersensitivity, and genomic instability. The mechanisms underlying these responses often involve bio-chemical and molecular signals generated in response to targeted and non-targeted events. In order to define and understand the bystander response to provide a basis for the understanding of non-targeted events and to elucidate the mechanisms involved, recent sophisticated research has been conducted with X-ray microbeams and charged heavy particle microbeams, and these studies have produced many new observations. Based on these observations, associations have been suggested to exist between the radio-adaptive and bystander responses. The present review focuses on these two phenomena, and summarizes observations supporting their existence, and discusses the linkage between them in light of recent results obtained from experiments utilizing microbeams. (author)

[A new peak detection algorithm of Raman spectra].

Science.gov (United States)

Jiang, Cheng-Zhi; Sun, Qiang; Liu, Ying; Liang, Jing-Qiu; An, Yan; Liu, Bing

2014-01-01

The authors proposed a new Raman peak recognition method named bi-scale correlation algorithm. The algorithm uses the combination of the correlation coefficient and the local signal-to-noise ratio under two scales to achieve Raman peak identification. We compared the performance of the proposed algorithm with that of the traditional continuous wavelet transform method through MATLAB, and then tested the algorithm with real Raman spectra. The results show that the average time for identifying a Raman spectrum is 0.51 s with the algorithm, while it is 0.71 s with the continuous wavelet transform. When the signal-to-noise ratio of Raman peak is greater than or equal to 6 (modern Raman spectrometers feature an excellent signal-to-noise ratio), the recognition accuracy with the algorithm is higher than 99%, while it is less than 84% with the continuous wavelet transform method. The mean and the standard deviations of the peak position identification error of the algorithm are both less than that of the continuous wavelet transform method. Simulation analysis and experimental verification prove that the new algorithm possesses the following advantages: no needs of human intervention, no needs of de-noising and background removal operation, higher recognition speed and higher recognition accuracy. The proposed algorithm is operable in Raman peak identification.

Size-dependent dynamic stability analysis of microbeams actuated by piezoelectric voltage based on strain gradient elasticity theory

Energy Technology Data Exchange (ETDEWEB)

Sahmani, Saeid; Bahrami, Mohsen [Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)

2015-01-15

In the current paper, dynamic stability analysis of microbeams subjected to piezoelectric voltage is presented in which the microbeam is integrated with piezoelectric layers on the lower and upper surfaces. Both of the flutter and divergence instabilities of microbeams with clamped-clamped and clamped-free boundary conditions are predicted corresponding to various values of applied voltage. To take size effect into account, the classical Timoshenko beam theory in conjunction with strain gradient elasticity theory is utilized to develop nonclassical beam model containing three additional internal length scale parameters. By using Hamilton's principle, the higher-order governing differential equations and associated boundary conditions are derived. Afterward, generalized differential quadrature method is employed to discretize the size-dependent governing differential equations along with clamped-clamped and clamped-free end supports. The critical piezoelectric voltages corresponding to various values dimensionless length scale parameter are evaluated and compared with those predicted by the classical beam theory. It is revealed that in the case of clamped-free boundary conditions, the both of flutter and divergence instabilities occur. However, for the clamped-clamped microbeams, only divergence instability takes place.

Quantitative Evaluation of Acetaminophen in Oral Solutions by Dispersive Raman Spectroscopy for Quality Control

OpenAIRE

Borio, Viviane G.; Vinha, RubensJr.; Nicolau, Renata A.; de Oliveira, Hueder Paulo M.; de Lima, Carlos J.; Silveira, LandulfoJr.

2012-01-01

This work used dispersive Raman spectroscopy to evaluate acetaminophen in commercially available formulations as an analytical methodology for quality control in the pharmaceutical industry. Raman spectra were collected using a near-infrared dispersive Raman spectrometer (830 nm, 50 mW, 20 s exposure time) coupled to a fiber optic probe. Solutions of acetaminophen diluted in excipient (70 to 120% of the commercial concentration of 200 mg/mL) were used to develop a calibration model based on p...

Effects of geometric nonlinearity in an adhered microbeam for measuring the work of adhesion

Science.gov (United States)

Fang, Wenqiang; Mok, Joyce; Kesari, Haneesh

2018-03-01

Design against adhesion in microelectromechanical devices is predicated on the ability to quantify this phenomenon in microsystems. Previous research related the work of adhesion for an adhered microbeam to the beam's unadhered length, and as such, interferometric techniques were developed to measure that length. We propose a new vibration-based technique that can be easily implemented with existing atomic force microscopy tools or similar metrology systems. To make such a technique feasible, we analysed a model of the adhered microbeam using the nonlinear beam theory put forth by Woinowsky-Krieger. We found a new relation between the work of adhesion and the unadhered length; this relation is more accurate than the one by Mastrangelo & Hsu (Mastrangelo & Hsu 1993 J. Microelectromech. S., 2, 44-55. (doi:10.1109/84.232594)) which is commonly used. Then, we derived a closed-form approximate relationship between the microbeam's natural frequency and its unadhered length. Results obtained from this analytical formulation are in good agreement with numerical results from three-dimensional nonlinear finite-element analysis.

Tackling field-portable Raman spectroscopy of real world samples

Science.gov (United States)

Shand, Neil C.

2008-10-01

A major challenge confronting first responders, customs authorities and other security-related organisations is the accurate, rapid, and safe identification of potentially hazardous chemicals outside a laboratory environment. Currently, a range of hand portable Raman equipment is commercially available that is low cost and increasingly more sophisticated. These systems are generally based on the 785nm Stokes shifted Raman technique with many using dispersive grating spectrometers. This technique offers a broad range of capabilities including the ability to analyse illicit drugs, explosives, chemical weapons and pre-cursors but still has some fundamental constraints. 'Real world' samples, such as those found at a crime scene, will often not be presented in the most accessible manner. Simple issues such as glass fluorescence can make an otherwise tractable sample impossible to analyse in-situ. A new generation of portable Raman equipment is currently being developed to address these issues. Consideration is given to the use of longer wavelength for fluorescence reduction. Alternative optical designs are being tested to compensate for the signal reduction incurred by moving to longer wavelengths. Furthermore, the use of anti-Stokes spectroscopy is being considered as well as investigating the robustness and portability of traditional Fourier Transform interferometer designs along with future advances in detector technology and ultra small spectrometers.

The Columbia University proton-induced soft x-ray microbeam.

Science.gov (United States)

Harken, Andrew D; Randers-Pehrson, Gerhard; Johnson, Gary W; Brenner, David J

2011-09-15

A soft x-ray microbeam using proton-induced x-ray emission (PIXE) of characteristic titanium (K(α) 4.5 keV) as the x-ray source has been developed at the Radiological Research Accelerator Facility (RARAF) at Columbia University. The proton beam is focused to a 120 μm × 50 μm spot on the titanium target using an electrostatic quadrupole quadruplet previously used for the charged particle microbeam studies at RARAF. The proton induced x-rays from this spot project a 50 μm round x-ray generation spot into the vertical direction. The x-rays are focused to a spot size of 5 μm in diameter using a Fresnel zone plate. The x-rays have an attenuation length of (1/e length of ~145 μm) allowing more consistent dose delivery across the depth of a single cell layer and penetration into tissue samples than previous ultra soft x-ray systems. The irradiation end station is based on our previous design to allow quick comparison to charged particle experiments and for mixed irradiation experiments.

First trial of spatial and temporal fractionations of the delivered dose using synchrotron microbeam radiation therapy

International Nuclear Information System (INIS)

Serduc, Raphael; Braeuer-Krisch, Elke; Bouchet, Audrey; Brochard, Thierry; Bravin, Alberto; Le Duc, Geraldine; Renaud, Luc; Laissue, Jean Albert

2009-01-01

The technical feasibility of temporal and spatial fractionations of the radiation dose has been evaluated using synchrotron microbeam radiation therapy for brain tumors in rats. A significant increase in lifespan (216%, p<0.0001) resulted when three fractions of microbeam irradiation were applied to the tumor through three different ports, orthogonal to each other, at 24 h intervals. However, there were no long-term survivors, and immunohistological studies revealed that 9 L tumors were not entirely ablated. (orig.)

First trial of spatial and temporal fractionations of the delivered dose using synchrotron microbeam radiation therapy

Energy Technology Data Exchange (ETDEWEB)

Serduc, Raphael [Toulouse Univ. (France). UPS Centre de Recherche Cerveau et Cognition; CNRS, CerCo, Toulouse (France); European Synchrotron Radiation Facility, 38 - Grenoble (France); Braeuer-Krisch, Elke; Bouchet, Audrey; Brochard, Thierry; Bravin, Alberto; Le Duc, Geraldine [European Synchrotron Radiation Facility, 38 - Grenoble (France); Renaud, Luc [Toulouse Univ. (France). UPS Centre de Recherche Cerveau et Cognition; CNRS, CerCo, Toulouse (France); Laissue, Jean Albert [Bern Univ. (Switzerland). Inst. of Pathology

2009-07-15

The technical feasibility of temporal and spatial fractionations of the radiation dose has been evaluated using synchrotron microbeam radiation therapy for brain tumors in rats. A significant increase in lifespan (216%, p<0.0001) resulted when three fractions of microbeam irradiation were applied to the tumor through three different ports, orthogonal to each other, at 24 h intervals. However, there were no long-term survivors, and immunohistological studies revealed that 9 L tumors were not entirely ablated. (orig.)

Non-destructive in situ study of “Mad Meg” by Pieter Bruegel the Elder using mobile X-ray fluorescence, X-ray diffraction and Raman spectrometers

Energy Technology Data Exchange (ETDEWEB)

Van de Voorde, Lien, E-mail: lien.vandevoorde@ugent.be [Ghent University, Department of Analytical Chemistry, X-ray Microspectroscopy and Imaging Research Group, Krijgslaan 281 S12, B-9000 Gent (Belgium); Van Pevenage, Jolien [Ghent University, Department of Analytical Chemistry, Raman Spectroscopy Research Group, Krijgslaan 281 S12, B-9000 Gent (Belgium); De Langhe, Kaat [Ghent University, Department of Archaeology, Archaeometry Research Group, Sint-Pietersnieuwstraat 35, B-9000 Gent (Belgium); De Wolf, Robin; Vekemans, Bart; Vincze, Laszlo [Ghent University, Department of Analytical Chemistry, X-ray Microspectroscopy and Imaging Research Group, Krijgslaan 281 S12, B-9000 Gent (Belgium); Vandenabeele, Peter [Ghent University, Department of Archaeology, Archaeometry Research Group, Sint-Pietersnieuwstraat 35, B-9000 Gent (Belgium); Martens, Maximiliaan P.J. [Ghent University, Department of Art, Music and Theatre Sciences, Blandijnberg 2, B-9000 Gent (Belgium)

2014-07-01

“Mad Meg”, a figure of Flemish folklore, is the subject of a famous oil-on-panel painting by the Flemish renaissance artist Pieter Bruegel the Elder, exhibited in the Museum Mayer van den Bergh (Antwerp, Belgium). This article reports on the in situ chemical characterization of this masterpiece by using currently available state-of-the-art portable analytical instruments. The applied non-destructive analytical approach involved the use of a) handheld X-ray fluorescence instrumentation for retrieving elemental information and b) portable X-ray fluorescence/X-ray diffraction instrumentation and laser-based Raman spectrometers for obtaining structural/molecular information. Next to material characterization of the used pigments and of the different preparation layers of the painting, also the verification of two important historical iconographic hypotheses is performed concerning the economic way of painting by Brueghel, and whether or not he used blue smalt pigment for painting the boat that appears towards the top of the painting. The pigments identified are smalt pigment (65% SiO{sub 2} + 15% K{sub 2}O + 10% CoO + 5% Al{sub 2}O{sub 3}) for the blue color present in all blue areas of the painting, probably copper resinate for the green colors, vermillion (HgS) as red pigment and lead white is used to form different colors. The comparison of blue pigments used on different areas of the painting gives no differences in the elemental fingerprint which confirms the existing hypothesis concerning the economic painting method by Bruegel. - Highlights: • In situ, non-destructive investigation of a famous painting by Pieter Bruegel. • Use of a new, commercial available, portable XRF/XRD instrumentation. • Multi-methodological approach: make also use of a mobile Raman spectrometer. • Used pigments and different preparation layers of the painting are characterized. • The verification of two important historical iconographic hypotheses are performed.

Non-destructive in situ study of “Mad Meg” by Pieter Bruegel the Elder using mobile X-ray fluorescence, X-ray diffraction and Raman spectrometers

International Nuclear Information System (INIS)

Van de Voorde, Lien; Van Pevenage, Jolien; De Langhe, Kaat; De Wolf, Robin; Vekemans, Bart; Vincze, Laszlo; Vandenabeele, Peter; Martens, Maximiliaan P.J.

2014-01-01

“Mad Meg”, a figure of Flemish folklore, is the subject of a famous oil-on-panel painting by the Flemish renaissance artist Pieter Bruegel the Elder, exhibited in the Museum Mayer van den Bergh (Antwerp, Belgium). This article reports on the in situ chemical characterization of this masterpiece by using currently available state-of-the-art portable analytical instruments. The applied non-destructive analytical approach involved the use of a) handheld X-ray fluorescence instrumentation for retrieving elemental information and b) portable X-ray fluorescence/X-ray diffraction instrumentation and laser-based Raman spectrometers for obtaining structural/molecular information. Next to material characterization of the used pigments and of the different preparation layers of the painting, also the verification of two important historical iconographic hypotheses is performed concerning the economic way of painting by Brueghel, and whether or not he used blue smalt pigment for painting the boat that appears towards the top of the painting. The pigments identified are smalt pigment (65% SiO 2 + 15% K 2 O + 10% CoO + 5% Al 2 O 3 ) for the blue color present in all blue areas of the painting, probably copper resinate for the green colors, vermillion (HgS) as red pigment and lead white is used to form different colors. The comparison of blue pigments used on different areas of the painting gives no differences in the elemental fingerprint which confirms the existing hypothesis concerning the economic painting method by Bruegel. - Highlights: • In situ, non-destructive investigation of a famous painting by Pieter Bruegel. • Use of a new, commercial available, portable XRF/XRD instrumentation. • Multi-methodological approach: make also use of a mobile Raman spectrometer. • Used pigments and different preparation layers of the painting are characterized. • The verification of two important historical iconographic hypotheses are performed

Computational modelling of the cerebral cortical microvasculature: effect of x-ray microbeams versus broad beam irradiation

Science.gov (United States)

Merrem, A.; Bartzsch, S.; Laissue, J.; Oelfke, U.

2017-05-01

Microbeam Radiation Therapy is an innovative pre-clinical strategy which uses arrays of parallel, tens of micrometres wide kilo-voltage photon beams to treat tumours. These x-ray beams are typically generated on a synchrotron source. It was shown that these beam geometries allow exceptional normal tissue sparing from radiation damage while still being effective in tumour ablation. A final biological explanation for this enhanced therapeutic ratio has still not been found, some experimental data support an important role of the vasculature. In this work, the effect of microbeams on a normal microvascular network of the cerebral cortex was assessed in computer simulations and compared to the effect of homogeneous, seamless exposures at equal energy absorption. The anatomy of a cerebral microvascular network and the inflicted radiation damage were simulated to closely mimic experimental data using a novel probabilistic model of radiation damage to blood vessels. It was found that the spatial dose fractionation by microbeam arrays significantly decreased the vascular damage. The higher the peak-to-valley dose ratio, the more pronounced the sparing effect. Simulations of the radiation damage as a function of morphological parameters of the vascular network demonstrated that the distribution of blood vessel radii is a key parameter determining both the overall radiation damage of the vasculature and the dose-dependent differential effect of microbeam irradiation.

Sparse-sampling with time-encoded (TICO) stimulated Raman scattering for fast image acquisition

Science.gov (United States)

Hakert, Hubertus; Eibl, Matthias; Karpf, Sebastian; Huber, Robert

2017-07-01

Modern biomedical imaging modalities aim to provide researchers a multimodal contrast for a deeper insight into a specimen under investigation. A very promising technique is stimulated Raman scattering (SRS) microscopy, which can unveil the chemical composition of a sample with a very high specificity. Although the signal intensities are enhanced manifold to achieve a faster acquisition of images if compared to standard Raman microscopy, there is a trade-off between specificity and acquisition speed. Commonly used SRS concepts either probe only very few Raman transitions as the tuning of the applied laser sources is complicated or record whole spectra with a spectrometer based setup. While the first approach is fast, it reduces the specificity and the spectrometer approach records whole spectra -with energy differences where no Raman information is present-, which limits the acquisition speed. Therefore, we present a new approach based on the TICO-Raman concept, which we call sparse-sampling. The TICO-sparse-sampling setup is fully electronically controllable and allows probing of only the characteristic peaks of a Raman spectrum instead of always acquiring a whole spectrum. By reducing the spectral points to the relevant peaks, the acquisition time can be greatly reduced compared to a uniformly, equidistantly sampled Raman spectrum while the specificity and the signal to noise ratio (SNR) are maintained. Furthermore, all laser sources are completely fiber based. The synchronized detection enables a full resolution of the Raman signal, whereas the analogue and digital balancing allows shot noise limited detection. First imaging results with polystyrene (PS) and polymethylmethacrylate (PMMA) beads confirm the advantages of TICO sparse-sampling. We achieved a pixel dwell time as low as 35 μs for an image differentiating both species. The mechanical properties of the applied voice coil stage for scanning the sample currently limits even faster acquisition.

Vibration analysis of a rotating functionally graded tapered microbeam based on the modified couple stress theory by DQEM

Science.gov (United States)

Ghadiri, Majid; Shafiei, Navvab; Alireza Mousavi, S.

2016-09-01

Due to having difficulty in solving governing nonlinear differential equations of a non-uniform microbeam, a few numbers of authors have studied such fields. In the present study, for the first time, the size-dependent vibration behavior of a rotating functionally graded (FG) tapered microbeam based on the modified couple stress theory is investigated using differential quadrature element method (DQEM). It is assumed that physical and mechanical properties of the FG microbeam are varying along the thickness that will be defined as a power law equation. The governing equations are determined using Hamilton's principle, and DQEM is presented to obtain the results for cantilever and propped cantilever boundary conditions. The accuracy and validity of the results are shown in several numerical examples. In order to display the influence of size on the first two natural frequencies and consequently changing of some important microbeam parameters such as material length scale, rate of cross section, angular velocity and gradient index of the FG material, several diagrams and tables are represented. The results of this article can be used in designing and optimizing elastic and rotary-type micro-electro-mechanical systems like micro-motors and micro-robots including rotating parts.

Measurement of minute local strain in semiconductor materials and electronic devices by using a highly parallel X-ray microbeam

International Nuclear Information System (INIS)

Matsui, J.; Tsusaka, Y.; Yokoyama, K.; Takeda, S.; Katou, M.; Kurihara, H.; Watanabe, K.; Kagoshima, Y.; Kimura, S.

2003-01-01

We have developed an X-ray microbeam with a small angular divergence by adopting X-ray optics with successive use of asymmetric Bragg reflection from silicon crystals for the both polarizations of the synchrotron X-rays. The microbeam actually obtained is several microns in size and possesses an angular divergence of less than 2 arcsec which enables us to measure the strain of 10 -5 -10 -6 . By scanning the sample against the microbeam, distribution of the minute local strain in various regions of semiconductor crystals for electronic devices, e.g., the strain around the SiO 2 /Si film edge in silicon devices, the strain in an InGaAsP/InP stripe laser were measured

Laser-induced radiation microbeam technology and simultaneous real-time fluorescence imaging in live cells.

Science.gov (United States)

Botchway, Stanley W; Reynolds, Pamela; Parker, Anthony W; O'Neill, Peter

2012-01-01

The use of nano- and microbeam techniques to induce and identify subcellular localized energy deposition within a region of a living cell provides a means to investigate the effects of low radiation doses. Particularly within the nucleus where the propagation and processing of deoxyribonucleic acid (DNA) damage (and repair) in both targeted and nontargeted cells, the latter being able to study cell-cell (bystander) effects. We have pioneered a near infrared (NIR) femtosecond laser microbeam to mimic ionizing radiation through multiphoton absorption within a 3D femtoliter volume of a highly focused Gaussian laser beam. The novel optical microbeam mimics both complex ionizing and UV-radiation-type cell damage including double strand breaks (DSBs). Using the microbeam technology, we have been able to investigate the formation of DNA DSB and subsequent recruitment of repair proteins to the submicrometer size site of damage introduced in viable cells. The use of a phosphorylated H2AX (γ-H2AX a marker for DSBs, visualized by immunofluorescent staining) and real-time imaging of fluorescently labeling proteins, the dynamics of recruitment of repair proteins in viable mammalian cells can be observed. Here we show the recruitment of ATM, p53 binding protein 1 (53BP1), and RAD51, an integral protein of the homologous recombination process in the DNA repair pathway and Ku-80-GFP involved in the nonhomologous end joining (NHEJ) pathway as exemplar repair process to show differences in the repair kinetics of DNA DSBs. The laser NIR multiphoton microbeam technology shows persistent DSBs at later times post laser irradiation which are indicative of DSBs arising at replication presumably from UV photoproducts or clustered damage containing single strand breaks (SSBs) that are also observed. Effects of the cell cycle may also be investigated in real time. Postirradiation and fixed cells studies show that in G1 cells a fraction of multiphoton laser-induced DSBs is persistent for >6h

Combined raman/laser-induced breakdown spectrometer: space and non-space applications

NARCIS (Netherlands)

Sandtke, M.; Laan, E.C.; Ahlers, B.

2010-01-01

TNO has developed the combination of two spectroscopic analysis methods in one instrument. Raman spectroscopy and Laser-induced Breakdown Spectroscopy (LIBS) were brought together for an instrument to be flown on the ExoMars mission from the European Space Agency (ESA) to investigate the Martian

A proton microbeam deflection system to scan target surfaces

International Nuclear Information System (INIS)

Heck, D.

1978-12-01

A system to deflect the proton beam within the Karlsruhe microbeam setup is described. The deflection is achieved whithin a transverse electrical field generated between parallel electrodes. Their tension is controlled by a pattern generator, thus enabling areal and line scans with a variable number of scan points at variable scan speed. The application is demonstrated at two different examples. (orig.) [de

Quantitative determination of the human breast milk macronutrients by near-infrared Raman spectroscopy

Science.gov (United States)

Motta, Edlene d. C. M.; Zângaro, Renato A.; Silveira, Landulfo, Jr.

2012-03-01

This work proposes the evaluation of the macronutrient constitution of human breast milk based on the spectral information provided by near-infrared Raman spectroscopy. Human breast milk (5 mL) from a subject was collected during the first two weeks of breastfeeding and stocked in -20°C freezer. Raman spectra were measured using a Raman spectrometer (830 nm excitation) coupled to a fiber based Raman probe. Spectra of human milk were dominated by bands of proteins, lipids and carbohydrates in the 600-1800 cm-1 spectral region. Raman spectroscopy revealed differences in the biochemical constitution of human milk depending on the time of breastfeeding startup. This technique could be employed to develop a classification routine for the milk in Human Milk Banking (HMB) depending on the nutritional facts.

A Galerkin-Parameterization Method for the Optimal Control of Smart Microbeams

Directory of Open Access Journals (Sweden)

Marwan Abukhaled

2009-01-01

Full Text Available A proposed computational method is applied to damp out the excess vibrations in smart microbeams, where the control action is implemented using piezoceramic actuators. From a mathematical point of view, we wish to determine the optimal boundary actuators that minimize a given energy-based performance measure. The minimization of the performance measure over the actuators is subjected to the full motion of the structural vibrations of the micro-beams. A direct state-control parametrization approach is proposed where the shifted Legendre polynomials are employed to solve the optimization problem. Legendre operational matrix and the properties of Kronecker product are utilized to find the approximated optimal trajectory and optimal control law of the lumped parameter systems with respect to the quadratic cost function by solving linear algebraic equations. Numerical examples are provided to demonstrate the applicability and efficiency of the proposed approach.

Rapid, sensitive and reproducible method for point-of-collection screening of liquid milk for adulterants using a portable Raman spectrometer with novel optimized sample well

Science.gov (United States)

Nieuwoudt, Michel K.; Holroyd, Steve E.; McGoverin, Cushla M.; Simpson, M. Cather; Williams, David E.

2017-02-01

Point-of-care diagnostics are of interest in the medical, security and food industry, the latter particularly for screening food adulterated for economic gain. Milk adulteration continues to be a major problem worldwide and different methods to detect fraudulent additives have been investigated for over a century. Laboratory based methods are limited in their application to point-of-collection diagnosis and also require expensive instrumentation, chemicals and skilled technicians. This has encouraged exploration of spectroscopic methods as more rapid and inexpensive alternatives. Raman spectroscopy has excellent potential for screening of milk because of the rich complexity inherent in its signals. The rapid advances in photonic technologies and fabrication methods are enabling increasingly sensitive portable mini-Raman systems to be placed on the market that are both affordable and feasible for both point-of-care and point-of-collection applications. We have developed a powerful spectroscopic method for rapidly screening liquid milk for sucrose and four nitrogen-rich adulterants (dicyandiamide (DCD), ammonium sulphate, melamine, urea), using a combined system: a small, portable Raman spectrometer with focusing fibre optic probe and optimized reflective focusing wells, simply fabricated in aluminium. The reliable sample presentation of this system enabled high reproducibility of 8% RSD (residual standard deviation) within four minutes. Limit of detection intervals for PLS calibrations ranged between 140 - 520 ppm for the four N-rich compounds and between 0.7 - 3.6 % for sucrose. The portability of the system and reliability and reproducibility of this technique opens opportunities for general, reagentless adulteration screening of biological fluids as well as milk, at point-of-collection.

Measurement of minute local strain in semiconductor materials and electronic devices by using a highly parallel X-ray microbeam

CERN Document Server

Matsui, J; Yokoyama, K; Takeda, S; Katou, M; Kurihara, H; Watanabe, K; Kagoshima, Y; Kimura, S

2003-01-01

We have developed an X-ray microbeam with a small angular divergence by adopting X-ray optics with successive use of asymmetric Bragg reflection from silicon crystals for the both polarizations of the synchrotron X-rays. The microbeam actually obtained is several microns in size and possesses an angular divergence of less than 2 arcsec which enables us to measure the strain of 10 sup - sup 5 -10 sup - sup 6. By scanning the sample against the microbeam, distribution of the minute local strain in various regions of semiconductor crystals for electronic devices, e.g., the strain around the SiO sub 2 /Si film edge in silicon devices, the strain in an InGaAsP/InP stripe laser were measured.

Measurement of minute local strain in semiconductor materials and electronic devices by using a highly parallel X-ray microbeam

Energy Technology Data Exchange (ETDEWEB)

Matsui, J. E-mail: matsui@sci.himeji-tech.ac.jp; Tsusaka, Y.; Yokoyama, K.; Takeda, S.; Katou, M.; Kurihara, H.; Watanabe, K.; Kagoshima, Y.; Kimura, S

2003-01-01

We have developed an X-ray microbeam with a small angular divergence by adopting X-ray optics with successive use of asymmetric Bragg reflection from silicon crystals for the both polarizations of the synchrotron X-rays. The microbeam actually obtained is several microns in size and possesses an angular divergence of less than 2 arcsec which enables us to measure the strain of 10{sup -5}-10{sup -6}. By scanning the sample against the microbeam, distribution of the minute local strain in various regions of semiconductor crystals for electronic devices, e.g., the strain around the SiO{sub 2}/Si film edge in silicon devices, the strain in an InGaAsP/InP stripe laser were measured.

Raman Spectroscopy for In-Line Water Quality Monitoring—Instrumentation and Potential

Directory of Open Access Journals (Sweden)

Zhiyun Li

2014-09-01

Full Text Available Worldwide, the access to safe drinking water is a huge problem. In fact, the number of persons without safe drinking water is increasing, even though it is an essential ingredient for human health and development. The enormity of the problem also makes it a critical environmental and public health issue. Therefore, there is a critical need for easy-to-use, compact and sensitive techniques for water quality monitoring. Raman spectroscopy has been a very powerful technique to characterize chemical composition and has been applied to many areas, including chemistry, food, material science or pharmaceuticals. The development of advanced Raman techniques and improvements in instrumentation, has significantly improved the performance of modern Raman spectrometers so that it can now be used for detection of low concentrations of chemicals such as in-line monitoring of chemical and pharmaceutical contaminants in water. This paper briefly introduces the fundamentals of Raman spectroscopy, reviews the development of Raman instrumentations and discusses advanced and potential Raman techniques for in-line water quality monitoring.

Wavelength Selection For Laser Raman Spectroscopy of Putative Martian Habitats and Biomolecules

Science.gov (United States)

Wynn-Williams, D. D.; Newton, E. M. G.; Edwards, H. G. M.

Pigments are key potential biomarkers for any former life on Mars because of the selective pressure of solar radiation on any biological system that could have evolved at its surface. We have found that the near -Infrared laser Raman spectrometer available to use was eminently suitable for diagnostic analysis of pigments because of their minimal autofluorescence at its 1064 nm excitation wav elength. However, we have now evaluated a diverse range of excitation wavelengths to confirm this choice, to ensure that we have the best technique to seek for pigments and their derivatives from any former surface life on Mars. The Raman is weak relative to fluorescence, which results in elevated baseline and concurrent swamping of Raman bands. We confirm the molecular information available from near-IR FT Raman spectra for two highly pigmented UV-tolerant epilithic Antarctic lichens (Acarospora chlorop hana and Caloplaca saxicola) from Victoria Land, a whole endolithic microbial community and endolithic cyanobacterium Chroococcidiopsis from within translucent sandstone of the Trans -Antarctic Mountains, and the free- living cyanobacterium Nostoc commune from Alexander Island, Antarctic Peninsula region. We also show that much of the information we require on biomolecules is not evident from lasers of shorter wavelengths. A miniature 1064 nm Raman spectrometer with an In-Ga-As detector sensitive to IR is being developed by Montana State University (now existing as a prototype) as the prime instrument for a proposed UK-led Mars rover mission (Vanguard). Preliminary spectra from this system confirm the suitability of the near-IR laser.

Detection and quantitative analysis of ferrocyanide and ferricyanide: FY 93 Florida State University Raman spectroscopy report

Energy Technology Data Exchange (ETDEWEB)

Mann, C.K.; Vickers, T.J. [Florida State Univ., Tallahassee, FL (United States). Dept. of Chemistry

1994-10-11

This report provides a summary of work to develop and investigate the feasibility of using Raman spectroscopy with tank waste materials. It contains Raman spectra from organics, such as ethylenediaminetetraacetic acid (EDTA), hydroxyethylenediaminetetraacteic acid (HEDTA), imino diacetic acid (IDA), kerosene, tributyl phosphate (TBP), acetone and butanol, anticipated to be present in tank wastes and spectra from T-107 real and BY-104 simulant materials. The results of investigating Raman for determining moisture content in tank materials are also presented. A description of software algorithms developed to process Raman spectra from a dispersive grating spectrometer system and an in initial design for a data base to support qualitative and quantitative application of remote Raman sensing with tank wastes.

Detection and quantitative analysis of ferrocyanide and ferricyanide: FY 93 Florida State University Raman spectroscopy report

International Nuclear Information System (INIS)

Mann, C.K.; Vickers, T.J.

1994-01-01

This report provides a summary of work to develop and investigate the feasibility of using Raman spectroscopy with tank waste materials. It contains Raman spectra from organics, such as ethylenediaminetetraacetic acid (EDTA), hydroxyethylenediaminetetraacteic acid (HEDTA), imino diacetic acid (IDA), kerosene, tributyl phosphate (TBP), acetone and butanol, anticipated to be present in tank wastes and spectra from T-107 real and BY-104 simulant materials. The results of investigating Raman for determining moisture content in tank materials are also presented. A description of software algorithms developed to process Raman spectra from a dispersive grating spectrometer system and an in initial design for a data base to support qualitative and quantitative application of remote Raman sensing with tank wastes

Next generation in-situ optical Raman sensor for seawater investigations

Science.gov (United States)

Kolomijeca, A.; Kwon, Y.-H.; Ahmad, H.; Kronfeldt, H.-D.

2012-04-01

We introduce the next generation of optical sensors based on a combination of surfaced enhanced Raman scattering (SERS) and shifted excitation Raman difference spectroscopy (SERDS) suited for investigations of tiny concentrations of pollutions in the seawater. First field measurements were carried out in the Arctic area which is of global interest since it is more affected by global warming caused climatic changes than any other areas of our planet and it is a recipient for many toxic organic pollutants. A significant long-range atmospheric transport of pollutants to Svalbard is mainly originated from industrialized countries in Europe and North America during the last decades. Therefore, the main interest is to investigate the Arctic water column and also the sediments. Standard chemical methods for water/sediment analysis are extremely accurate but complex and time-consuming. The primary objective of our study was to develop a fast response in-situ optical sensor for easy to use and quick analysis. The system comprises several components: a handheld measurement head containing a 671 nm microsystem diode laser and the Raman optical bench, a laser driver electronics board, a custom-designed miniature spectrometer with an optical resolution of 8 cm-1 and a netbook to control the spectrometer as well as for data evaluation. We introduced for the first time the portable Raman sensor system on an Artic sea-trial during a three week cruise on board of the James Clark Ross research vessel in August 2011. Numerous Raman and SERS measurements followed by SERDS evaluations were taken around locations 78° N and 9° E. Different SERS substrates developed for SERS measurements in sea-water were tested for their capability to detect different substances (PAHs) in the water down to very small (nmol/l) concentrations. Stability tests of the substrates were carried out also for the applicability of our system e.g. on a mooring. Details of the in-situ Raman sensor were presented

New capabilities of the Zagreb ion microbeam system

International Nuclear Information System (INIS)

Jaksic, M.; Bogdanovic Radovic, I.; Bogovac, M.; Desnica, V.; Fazinic, S.; Karlusic, M.; Medunic, Z.; Muto, H.; Pastuovic, Z.; Siketic, Z.; Skukan, N.; Tadic, T.

2007-01-01

The installation of a new 1.0 MV Tandetron accelerator and a recent upgrade of the 6.0 MV Tandem Van de Graaff accelerator increased the application possibilities of the Zagreb ion microbeam system. Several ion sources enable now the selection of a wide variety of ions. Most of them can be focused by the existing microprobe system. Sample positioning tools and new scanner control options are implemented in the new generation of SPECTOR data acquisition system. Details of the upgrades are presented

Continuation of mitosis after selective laser microbeam destruction of the centriolar region

Energy Technology Data Exchange (ETDEWEB)

Berns, N.W.; Richardson, S.M.

1977-12-01

The centriole regions of prophase PTK2 cells were irradiated with a laser microbeam. Cells continued through mitosis normally. Ultrastructural analysis revealed either an absence of centrioles or severely damaged centrioles at the irradiated poles. Microtubules appeared to focus into pericentriolar cloud material.

Continuation of mitosis after selective laser microbeam destruction of the centriolar region

International Nuclear Information System (INIS)

Berns, N.W.; Richardson, S.M.

1977-01-01

The centriole regions of prophase PTK2 cells were irradiated with a laser microbeam. Cells continued through mitosis normally. Ultrastructural analysis revealed either an absence of centrioles or severely damaged centrioles at the irradiated poles. Microtubules appeared to focus into pericentriolar cloud material

Combining Raman and laser induced breakdown spectroscopy by double pulse lasing.

Science.gov (United States)

Lednev, Vasily N; Pershin, Sergey M; Sdvizhenskii, Pavel A; Grishin, Mikhail Ya; Fedorov, Alexander N; Bukin, Vladimir V; Oshurko, Vadim B; Shchegolikhin, Alexander N

2018-01-01

A new approach combining Raman spectrometry and laser induced breakdown spectrometry (LIBS) within a single laser event was suggested. A pulsed solid state Nd:YAG laser running in double pulse mode (two frequency-doubled sequential nanosecond laser pulses with dozens microseconds delay) was used to combine two spectrometry methods within a single instrument (Raman/LIBS spectrometer). First, a low-energy laser pulse (power density far below ablation threshold) was used for Raman measurements while a second powerful laser pulse created the plasma suitable for LIBS analysis. A short time delay between two successive pulses allows measuring LIBS and Raman spectra at different moments but within a single laser flash-lamp pumping. Principal advantages of the developed instrument include high quality Raman/LIBS spectra acquisition (due to optimal gating for Raman/LIBS independently) and absence of target thermal alteration during Raman measurements. A series of high quality Raman and LIBS spectra were acquired for inorganic salts (gypsum, anhydrite) as well as for pharmaceutical samples (acetylsalicylic acid). To the best of our knowledge, the quantitative analysis feasibility by combined Raman/LIBS instrument was demonstrated for the first time by calibration curves construction for acetylsalicylic acid (Raman) and copper (LIBS) in gypsum matrix. Combining ablation pulses and Raman measurements (LIBS/Raman measurements) within a single instrument makes it an efficient tool for identification of samples hidden by non-transparent covering or performing depth profiling analysis including remote sensing. Graphical abstract Combining Raman and laser induced breakdown spectroscopy by double pulse lasing.

Raman Spectroscopy for In-Line Water Quality Monitoring — Instrumentation and Potential

Science.gov (United States)

Li, Zhiyun; Deen, M. Jamal; Kumar, Shiva; Selvaganapathy, P. Ravi

2014-01-01

Worldwide, the access to safe drinking water is a huge problem. In fact, the number of persons without safe drinking water is increasing, even though it is an essential ingredient for human health and development. The enormity of the problem also makes it a critical environmental and public health issue. Therefore, there is a critical need for easy-to-use, compact and sensitive techniques for water quality monitoring. Raman spectroscopy has been a very powerful technique to characterize chemical composition and has been applied to many areas, including chemistry, food, material science or pharmaceuticals. The development of advanced Raman techniques and improvements in instrumentation, has significantly improved the performance of modern Raman spectrometers so that it can now be used for detection of low concentrations of chemicals such as in-line monitoring of chemical and pharmaceutical contaminants in water. This paper briefly introduces the fundamentals of Raman spectroscopy, reviews the development of Raman instrumentations and discusses advanced and potential Raman techniques for in-line water quality monitoring. PMID:25230309

Multifocus confocal Raman microspectroscopy for fast multimode vibrational imaging of living cells.

Science.gov (United States)

Okuno, Masanari; Hamaguchi, Hiro-o

2010-12-15

We have developed a multifocus confocal Raman microspectroscopic system for the fast multimode vibrational imaging of living cells. It consists of an inverted microscope equipped with a microlens array, a pinhole array, a fiber bundle, and a multichannel Raman spectrometer. Forty-eight Raman spectra from 48 foci under the microscope are simultaneously obtained by using multifocus excitation and image-compression techniques. The multifocus confocal configuration suppresses the background generated from the cover glass and the cell culturing medium so that high-contrast images are obtainable with a short accumulation time. The system enables us to obtain multimode (10 different vibrational modes) vibrational images of living cells in tens of seconds with only 1 mW laser power at one focal point. This image acquisition time is more than 10 times faster than that in conventional single-focus Raman microspectroscopy.

Gold Nanoparticles as Probes for Nano-Raman Spectroscopy: Preliminary Experimental Results and Modeling

Directory of Open Access Journals (Sweden)

V. Le Nader

2012-01-01

Full Text Available This paper presents an effective Tip-Enhanced Raman Spectrometer (TERS in backscattering reflection configuration. It combines a tip-probe nanopositioning system with Raman spectroscope. Specific tips were processed by anchoring gold nanoparticles on the apex of tapered optical fibers, prepared by an improved chemical etching method. Hence, it is possible to expose a very small area of the sample (~20 nm2 to the very strong local electromagnetic field generated by the lightning rod effect. This experimental configuration was modelled and optimised using the finite element method, which takes into account electromagnetic effects as well as the plasmon resonance. Finally, TERS measurements on single-wall carbon nanotubes were successfully performed. These results confirm the high Raman scattering enhancement predicted by the modelling, induced by our new nano-Raman device.

Spatially resolved Raman spectroscopy study of transformed zones in magnesia-partially-stabilized zirconia

International Nuclear Information System (INIS)

Davskardt, R.H.; Veirs, D.K.; Ritchie, R.O.

1989-01-01

Raman vibrational spectroscopy provides an effective phase characterization technique in materials systems containing particle dispersions of the tetragonal and monoclinic polymorphs of zirconia, each of which yields a unique Raman spectrum. An investigation is reported to assess a novel, spatially resolved Raman spectroscopy system in the study of transformed zones surrounding cracks in partially stabilized MgO-ZrO 2 (PSZ). The experimental arrangement uses an imaging (two-dimensional) photomultiplier tube to produce a one-dimensional Raman profile of phase compositions along a slitlike laser beam without translation of either the sample or the laser beam and without scanning the spectrometer. Results from phase characterization studies of the size, frontal morphology, and extent of transformation of transformation zones surrounding cracks produced under monotonic and cyclic loading conditions are presented

An Experimental and Theoretical Investigation of Electrostatically Coupled Cantilever Microbeams

KAUST Repository

Ilyas, Saad

2016-06-16

We present an experimental and theoretical investigation of the static and dynamic behavior of electrostatically coupled laterally actuated silicon microbeams. The coupled beam resonators are composed of two almost identical flexible cantilever beams forming the two sides of a capacitor. The experimental and theoretical analysis of the coupled system is carried out and compared against the results of beams actuated with fixed electrodes individually. The pull-in characteristics of the electrostatically coupled beams are studied, including the pull-in time. The dynamics of the coupled dual beams are explored via frequency sweeps around the neighborhood of the natural frequencies of the system for different input voltages. Good agreement is reported among the simulation results and the experimental data. The results show considerable drop in the pull-in values as compared to single microbeam resonators. The dynamics of the coupled beam resonators are demonstrated as a way to increase the bandwidth of the resonator near primary resonance as well as a way to introduce increased frequency shift, which can be promising for resonant sensing applications. Moreover the dynamic pull-in characteristics are also studied and proposed as a way to sense the shift in resonance frequency.

Optical Fiber-Tip Sensors Based on In-Situ µ-Printed Polymer Suspended-Microbeams.

Science.gov (United States)

Yao, Mian; Ouyang, Xia; Wu, Jushuai; Zhang, A Ping; Tam, Hwa-Yaw; Wai, P K A

2018-06-05

Miniature optical fiber-tip sensors based on directly µ-printed polymer suspended-microbeams are presented. With an in-house optical 3D μ-printing technology, SU-8 suspended-microbeams are fabricated in situ to form Fabry⁻Pérot (FP) micro-interferometers on the end face of standard single-mode optical fiber. Optical reflection spectra of the fabricated FP micro-interferometers are measured and fast Fourier transform is applied to analyze the cavity of micro-interferometers. The applications of the optical fiber-tip sensors for refractive index (RI) sensing and pressure sensing, which showed 917.3 nm/RIU to RI change and 4.29 nm/MPa to pressure change, respectively, are demonstrated in the experiments. The sensors and their optical µ-printing method unveil a new strategy to integrate complicated microcomponents on optical fibers toward 'lab-on-fiber' devices and applications.

A study of x-ray microbeam stress measurement for local area

International Nuclear Information System (INIS)

Natsume, Yoshitaka; Miyakawa, Susumu

1987-01-01

A new type X-ray microbeam equipment which is capable of three-dimensional oscillation at an X-ray radiation position was used to measure the residual stress of pure iron powder and bending plate specimens as well as that in the vicinity of fatigue crack tip of 1/2 CT specimen. The results obtained are summerized as follows. (1) Diffraction profiles of pure iron powder with diameter 0.02 ∼ 0.03 μm particle size obtained by the present microbeam technique in the beam area of 80 μm in diamether and measuring time more than 800 sec showed Kα 1 and Kα 2 peaks clearly, so that these profiles are good enough for stress measurement. (2) The measured stress of pure iron powder with diameter 10 ∼ 25 μm particle size in the beam area of 80 μm in diameter was not equal to 0 MPa. The measured stress varied greatly and was independent of measuring time. (3) The measured stress of pure iron powder with diameter 0.02 ∼ 0.03 μm particle size in the beam area of 80 μm in diameter was almost 1 MPa, which shows the good accuracy of this X-ray micro-beam equipment. (4) The relation between the X-ray measured stress and the mechanically applied stress showed good agreement. (5) The distribution of residual stress at the vicinity of fatigue crack tip showed that the residual stress at the fatigue crack tip was compression and the residual stress in front of crack tip was tension. This tensile residual stress in front of crack tip existed in the area from 0.02 mm to 2 mm. (6) The above results show that the present equipment is advantageous in the investigation of local stress, shortening the measuring time without sacrificing the accuracy. (author)

Raman spectrum of natural and synthetic stishovite

Science.gov (United States)

Hemley, R.J.; Mao, Ho-kwang; Chao, E.C.T.

1986-01-01

Raman spectra of natural and synthetic samples of stishovite have been measured with a micro-optical spectrometer system. These spectra have a pattern that is characteristic of rutile-structured oxides. The spectrum of synthetic stishovite is characterized by well-resolved bands at 231, 589, 753, and 967 cm-1, which are assigned as the B1g, Eg, A1g, and B2g fundamentals, respectively, of the first-order Raman spectrum of the ideal, ordered structure. Natural stishovite obtained from Meteor Crater, Arizona has a first-order Raman spectrum that is fully consistent with that of the synthetic material. The observed spectrum of the natural sample, however, is weaker and has bands in addition to those identified as fundamentals in the spectrum of the synthetic material. A broad band at ???475 cm-1 may be indicative of glass or contaminants derived from the extraction procedure. Alternatively, this band may arise from multiphonon scattering that is enhanced by poor crystallinity or structural disorder in the natural shocked sample. ?? 1986 Springer-Verlag.

PREFACE: European Microbeam Analysis Society's 14th European Workshop on Modern Developments and Applications in Microbeam Analysis (EMAS 2015), Portorož, Slovenia, 3-7 May 2015

Science.gov (United States)

Llovet, Xavier; Matthews, Michael B.; Čeh, Miran; Langer, Enrico; Žagar, Kristina

2016-02-01

This volume of the IOP Conference Series: Materials Science and Engineering contains papers from the 14th Workshop of the European Microbeam Analysis Society (EMAS) on Modern Developments and Applications in Microbeam Analysis which took place from the 3rd to the 7th of May 2015 in the Grand Hotel Bernardin, Portorož, Slovenia. The primary aim of this series of workshops is to assess the state-of-the-art and reliability of microbeam analysis techniques. The workshops also provide a forum where students and young scientists starting out on a career in microbeam analysis can meet and discuss with the established experts. The workshops have a unique format comprising invited plenary lectures by internationally recognized experts, poster presentations by the participants and round table discussions on the key topics led by specialists in the field.This workshop was organized in collaboration with the Jožef Stefan Institute and SDM - Slovene Society for Microscopy. The technical programme included the following topics: electron probe microanalysis, STEM and EELS, materials applications, cathodoluminescence and electron backscatter diffraction (EBSD), and their applications. As at previous workshops there was also a special oral session for young scientists. The best presentation by a young scientist was awarded with an invitation to attend the 2016 Microscopy and Microanalysis meeting at Columbus, Ohio. The prize went to Shirin Kaboli, of the Department of Metals and Materials Engineering of McGill University (Montréal, Canada), for her talk entitled "Electron channelling contrast reconstruction with electron backscattered diffraction". The continuing relevance of the EMAS workshops and the high regard in which they are held internationally can be seen from the fact that 71 posters from 16 countries were on display at the meeting and that the participants came from as far away as Japan, Canada, USA, and Australia. A selection of participants with posters was invited

Parameter identification of an electrically actuated imperfect microbeam

KAUST Repository

Ruzziconi, Laura

2013-12-01

In this study we consider a microelectromechanical system (MEMS) and focus on extracting analytically the model parameters that describe its non-linear dynamic features accurately. The device consists of a clamped-clamped polysilicon microbeam electrostatically and electrodynamically actuated. The microbeam has imperfections in the geometry, which are related to the microfabrication process, resulting in many unknown and uncertain parameters of the device. The objective of the present paper is to introduce a simple but appropriate model which, despite the inevitable approximations, is able to describe and predict the most relevant aspects of the experimental response in a neighborhood of the first symmetric resonance. The modeling includes the main imperfections in the microstructure. The unknown parameters are settled via parametric identification. The approach is developed in the frequency domain and is based on matching both the frequency values and, remarkably, the frequency response curves, which are considered as the most salient features of the device response. Non-linearities and imperfections considerably complicate the identification process. Via the combined use of linear analysis and non-linear dynamic simulations, a single first symmetric mode reduced-order model is derived. Extensive numerical simulations are performed at increasing values of electrodynamic excitation. Comparison with experimental data shows a satisfactory concurrence of results not only at low electrodynamic voltage, but also at higher ones. This validates the proposed theoretical approach. We highlight its applicability, both in similar case-studies and, more in general, in systems. © 2013 Elsevier Ltd.

Biosignatures observed by Raman mapping in silicified materials

Science.gov (United States)

Foucher, F.; Westall, F.; Knoll, A.

2012-04-01

Establishing the biogenicity of ancient microbial remains is relatively difficult due to their simple shape and small size (micrometric-submicrometric). Potential biosignatures that remain in the rocks are related to morphological aspects of the potential microfossils, their chemical composition (carbon and associated elements), and evidence for metabolic activity (elemental isotopic signature, biominerals, corrosion/leaching features). Detection of biosignatures related to each of these microbial characteristics will increase the confidence with which biogenicity can be assigned to an unknown structure. However, given the small size of the microfossils and the consequent faint organic/geochemical traces, sophisticated instrumentation, such as mass spectrometers, electron microscopes, proton probes, nano-SIMS or even synchrotrons is generally required. In this study, we demonstrate the usefulness of Raman spectroscopy, and in particular Raman mapping, as a very powerful tool for the study of both organic and minerals biosignatures. Our investigations concern silicified, carbonaceous-walled microfossils from the Precambrian (700-800 Ma) Draken Formation, Spitsbergen (Svalbard). The microfossils consist of filamentous cyanobacterial mats containing trapped coccoidal planktonic microorganisms. The filaments are generally ~5 µm in width and the coccoidal structures are ~10µm in diameter. The Raman spectrometer used (WITec Alpha500 RA) allows compositional 2D/3D mapping at a sub-micrometric resolution of fossilised microorganisms, whose biogenicity had been previously established on the basis of their morphological characteristics and carbonaceous composition [1]. Complementary features were revealed by the micro-Raman mapping that may aid interpretation of biogenicity in an unknown structure. They included detection of opaline silica, titanium dioxide (anatase), pyrite and hydroxyapatite associated with the microfossils. Opaline silica is metastable and normally

Atomic force microscope with combined FTIR-Raman spectroscopy having a micro thermal analyzer

Science.gov (United States)

Fink, Samuel D [Aiken, SC; Fondeur, Fernando F [North Augusta, SC

2011-10-18

An atomic force microscope is provided that includes a micro thermal analyzer with a tip. The micro thermal analyzer is configured for obtaining topographical data from a sample. A raman spectrometer is included and is configured for use in obtaining chemical data from the sample.

Microbeam irradiation of the C. elegans nematode

International Nuclear Information System (INIS)

Bertucci, Antonella; Brenner, David J.; Pocock, Roger D.J.; Randers-Pehrson, Gerhard

2009-01-01

The understanding of complex radiation responses in biological systems, such as non-targeted effects as represented by the bystander response, can be enhanced by the use of genetically amenable model organisms. Almost all bystander studies to date have been carried out by using conventional single-cell in vitro systems, which are useful tools to characterize basic cellular and molecular responses. A few studies have been reported in monolayer explants and bystander responses have been also investigated in a three-dimensional normal human tissue system. However, despite the well-know usefulness of in vitro models, they cannot capture the complexity of radiation responses of living systems such as animal models. To carry out in vivo studies on the bystander effect we have developed a new technique to expose living organisms using proton microbeams. We report the use of a nematode C. elegans strain with a Green Fluorescent Protein (GFP) reporter for the hsp-4 heat-shock gene as an in vivo model for radiation studies. Exposing animals to heat and chemicals stressors leads to whole body increases in the hsp-4 protein reflected by enhanced fluorescence. We report here that γ-rays also can induce stress response in a dose dependent manner. However, whole body exposure to stress agents does not allow for evaluation of distance dependent response in non targeted tissues: the so-called bystander effect. We used the RARAF microbeam to site specifically deliver 3 MeV protons to a site in the tail of young worms. GFP expression was enhanced after 24 hours in a number dependent manner at distances > 100 μm from the site of irradiation. (author)

Higher order modes excitation of electrostatically actuated clamped–clamped microbeams: experimental and analytical investigation

KAUST Repository

Jaber, Nizar; Ramini, Abdallah; Carreno, Armando Arpys Arevalo; Younis, Mohammad I.

2016-01-01

© 2016 IOP Publishing Ltd. In this study, we demonstrate analytically and experimentally the excitations of the higher order modes of vibrations in electrostatically actuated clamped-clamped microbeam resonators. The concept is based on using

Infrared and Raman spectroscopy on synthetic glasses as analogues of planetary surfaces.

Science.gov (United States)

Weber, Iris; Morlok, Andreas; Klemme, Stephan; Dittmer, Isabelle; Stojic, Aleksandra N.; Hiesinger, Harald; Sohn, Martin; Helbert, Jörn

2015-04-01

One of the fundamental aims of space mission is to understand the physical, chemical, and geologic processes and conditions of planetary formation and evolution. For this purpose, it is important to investigate analog material to correctly interpret the returned spacecraft data, including the spectral information from remote planetary surfaces. For example, mid-infrared spectroscopy provides detailed information on the mineralogical compositions of planetary surfaces via remote sensing. Data is affected by numerous factors such as grain size, illumination geometry, space weathering, and temperature. These features need to be systematically investigated on analog material in terrestrial laboratories in order to understand the mineralogy/composition of a planetary surface. In addition, Raman spectroscopy allows non-destructive analyses of planetary surfaces in the case of a landing mission. Our work at the IRIS (Infrared spectroscopy for Interplanetary Studies) laboratory at the Institut für Planetologie produces spectra for a database of the ESA/JAXA BepiColombo mission to Mercury. Onboard is a mid-infrared spectrometer (MERTIS-Mercury Radiometer and Thermal Infrared Spectrometer). This unique instrument allows us to map spectral features in the 7-14 µm range, with a spatial resolution of ~500 m [1-5]. Comparably, using our Raman spectrometer, we are continuously contributing to the Raman database for upcoming mission, e.g., the Raman Laser Spectrometer (RLS) onboard of ExoMars [6]. Material on the surface of Mercury and the other terrestrial bodies was exposed to heavy impact cratering [4]. Depending on the P/T conditions during the impact, minerals on planetary surfaces can react with the formation of glassy material. Thus, understanding the effects of impact shock and heat on the mineral structure and the resulting corresponding change in the spectral properties is of high interest for the MERTIS project. Here, we present spectral information on the first glass

The mechanics of anaphase B in a basidiomycete as revealed by laser microbeam microsurgery

International Nuclear Information System (INIS)

Bayles, C.J.; Aist, J.R.; Berns, M.W.

1993-01-01

Bayles, C. J., Aist, J. R., and Berns, M. W. 1993. The mechanics of anaphase B in a basidiomycete as revealed by laser microbeam microsurgery. Experimental Mycology 17, 191-199. Cytoplasmic forces were found to be actively pulling on the spindle pole bodies during anaphase B in the dikaryotic, basidiomycete fungus, Helicobasidium mompa. When the spindle of one nucleus was severed with a laser microbeam at mid anaphase B, its two spindle pole bodies separated at a much faster rate than did those of the intact spindle in the other nucleus of the same cell. Since astral microtubule populations apparently reach their maximum during anaphase B in this fungus, we suggest that these microtubules may be involved in the cytoplasmic pulling forces. The spindle appears to act primarily as a governor, regulating the rate at which the spindle pole bodies are separated

Non-invasive blood glucose monitoring with Raman spectroscopy: prospects for device miniaturization

International Nuclear Information System (INIS)

Wróbel, M.S.

2016-01-01

The number of patients with diabetes has reached over 350 million, and still continues to increase. The need for regular blood glucose monitoring sparks the interest in the development of modern detection technologies. One of those methods, which allows for noninvasive measurements, is Raman spectroscopy. The ability of infrared light to penetrate deep into tissues allows for obtaining measurements through the skin without its perforation. This paper presents the limitations and possibilities of non-invasive blood glucose monitoring with Raman spectroscopy. Especially focusing on the possibilities for device miniaturization. Such device incorporates a Raman spectrometer, a fiber-optical probe, and a computing device (microcontroller, smartphone, etc.) which calculates the glucose concentration using specialized algorithms. Simplification of device design, as well as turbidity correction technique and a new proposed method of synchronized detection are described

[Laser Raman Spectroscopy and Its Application in Gas Hydrate Studies].

Science.gov (United States)

Fu, Juan; Wu, Neng-you; Lu, Hai-long; Wu, Dai-dai; Su, Qiu-cheng

2015-11-01

Gas hydrates are important potential energy resources. Microstructural characterization of gas hydrate can provide information to study the mechanism of gas hydrate formation and to support the exploitation and application of gas hydrate technology. This article systemly introduces the basic principle of laser Raman spectroscopy and summarizes its application in gas hydrate studies. Based on Raman results, not only can the information about gas composition and structural type be deduced, but also the occupancies of large and small cages and even hydration number can be calculated from the relative intensities of Raman peaks. By using the in-situ analytical technology, laser Raman specstropy can be applied to characterize the formation and decomposition processes of gas hydrate at microscale, for example the enclathration and leaving of gas molecules into/from its cages, to monitor the changes in gas concentration and gas solubility during hydrate formation and decomposition, and to identify phase changes in the study system. Laser Raman in-situ analytical technology has also been used in determination of hydrate structure and understanding its changing process under the conditions of ultra high pressure. Deep-sea in-situ Raman spectrometer can be employed for the in-situ analysis of the structures of natural gas hydrate and their formation environment. Raman imaging technology can be applied to specify the characteristics of crystallization and gas distribution over hydrate surface. With the development of laser Raman technology and its combination with other instruments, it will become more powerful and play a more significant role in the microscopic study of gas hydrate.

Feasibility of employing thick microbeams from superficial and orthovoltage kVp x-ray tubes for radiotherapy of superficial cancers

Science.gov (United States)

Kamali-Zonouzi, P.; Shutt, A.; Nisbet, A.; Bradley, D. A.

2017-11-01

Preclinical investigations of thick microbeams show these to be feasible for use in radiotherapeutic dose delivery. To create the beams we access a radiotherapy x-ray tube that is familiarly used within a conventional clinical environment, coupling this with beam-defining grids. Beam characterisation, both single and in the form of arrays, has been by use of both MCNP simulation and direct Gafchromic EBT film dosimetry. As a first step in defining optimal exit-beam profiles over a range of beam energies, simulation has been made of the x-ray tube and numbers of beam-defining parallel geometry grids, the latter being made to vary in thickness, slit separation and material composition. For a grid positioned after the treatment applicator, and of similar design to those used in the first part of the study, MCNP simulation and Gafchromic EBT film were then applied in examining the resultant radiation profiles. MCNP simulations and direct dosimetry both show useful thick microbeams to be produced from the x-ray tube, with peak-to-valley dose ratios (PVDRs) in the approximate range 8.8-13.9. Although the potential to create thick microbeams using radiotherapy x-ray tubes and a grid has been demonstrated, Microbeam Radiation Therapy (MRT) would still need to be approved outside of the preclinical setting, a viable treatment technique of clinical interest needing to benefit for instance from substantially improved x-ray tube dose rates.

Photoacoustic microbeam-oscillator with tunable resonance direction and amplitude

Science.gov (United States)

Wu, Qingjun; Li, Fanghao; Wang, Bo; Yi, Futing; Jiang, J. Z.; Zhang, Dongxian

2018-01-01

We successfully design one photoacoustic microbeam-oscillator actuated by nanosecond laser, which exhibits tunable resonance direction and amplitude. The mechanism of laser induced oscillation is systematically analyzed. Both simulation and experimental results reveal that the laser induced acoustic wave propagates in a multi-reflected mode, resulting in resonance in the oscillator. This newly-fabricated micrometer-sized beam-oscillator has an excellent actuation function, i.e., by tuning the laser frequency, the direction and amplitude of actuation can be efficiently altered, which will have potential industrial applications.

Nonlinear dynamics of an electrically actuated imperfect microbeam resonator: Experimental investigation and reduced-order modeling

KAUST Repository

Ruzziconi, Laura; Bataineh, Ahmad M.; Younis, Mohammad I.; Cui, Weili; Lenci, Stefano

2013-01-01

We present a study of the dynamic behavior of a microelectromechanical systems (MEMS) device consisting of an imperfect clamped-clamped microbeam subjected to electrostatic and electrodynamic actuation. Our objective is to develop a theoretical

The high throughput virtual slit enables compact, inexpensive Raman spectral imagers

Science.gov (United States)

Gooding, Edward; Deutsch, Erik R.; Huehnerhoff, Joseph; Hajian, Arsen R.

2018-02-01

Raman spectral imaging is increasingly becoming the tool of choice for field-based applications such as threat, narcotics and hazmat detection; air, soil and water quality monitoring; and material ID. Conventional fiber-coupled point source Raman spectrometers effectively interrogate a small sample area and identify bulk samples via spectral library matching. However, these devices are very slow at mapping over macroscopic areas. In addition, the spatial averaging performed by instruments that collect binned spectra, particularly when used in combination with orbital raster scanning, tends to dilute the spectra of trace particles in a mixture. Our design, employing free space line illumination combined with area imaging, reveals both the spectral and spatial content of heterogeneous mixtures. This approach is well suited to applications such as detecting explosives and narcotics trace particle detection in fingerprints. The patented High Throughput Virtual Slit1 is an innovative optical design that enables compact, inexpensive handheld Raman spectral imagers. HTVS-based instruments achieve significantly higher spectral resolution than can be obtained with conventional designs of the same size. Alternatively, they can be used to build instruments with comparable resolution to large spectrometers, but substantially smaller size, weight and unit cost, all while maintaining high sensitivity. When used in combination with laser line imaging, this design eliminates sample photobleaching and unwanted photochemistry while greatly enhancing mapping speed, all with high selectivity and sensitivity. We will present spectral image data and discuss applications that are made possible by low cost HTVS-enabled instruments.

Advances in miniature spectrometer and sensor development

Science.gov (United States)

Malinen, Jouko; Rissanen, Anna; Saari, Heikki; Karioja, Pentti; Karppinen, Mikko; Aalto, Timo; Tukkiniemi, Kari

2014-05-01

Miniaturization and cost reduction of spectrometer and sensor technologies has great potential to open up new applications areas and business opportunities for analytical technology in hand held, mobile and on-line applications. Advances in microfabrication have resulted in high-performance MEMS and MOEMS devices for spectrometer applications. Many other enabling technologies are useful for miniature analytical solutions, such as silicon photonics, nanoimprint lithography (NIL), system-on-chip, system-on-package techniques for integration of electronics and photonics, 3D printing, powerful embedded computing platforms, networked solutions as well as advances in chemometrics modeling. This paper will summarize recent work on spectrometer and sensor miniaturization at VTT Technical Research Centre of Finland. Fabry-Perot interferometer (FPI) tunable filter technology has been developed in two technical versions: Piezoactuated FPIs have been applied in miniature hyperspectral imaging needs in light weight UAV and nanosatellite applications, chemical imaging as well as medical applications. Microfabricated MOEMS FPIs have been developed as cost-effective sensor platforms for visible, NIR and IR applications. Further examples of sensor miniaturization will be discussed, including system-on-package sensor head for mid-IR gas analyzer, roll-to-roll printed Surface Enhanced Raman Scattering (SERS) technology as well as UV imprinted waveguide sensor for formaldehyde detection.

PREFACE: Proceedings of the 11th European Workshop of the European Microbeam Analysis Society (EMAS) on Modern Developments and Applications in Microbeam Analysis

Science.gov (United States)

2010-07-01

This volume of IOP Conference Series: Materials Science and Engineering contains papers from the 11th Workshop of the European Microbeam Analysis Society (EMAS) on Modern Developments and Applications in Microbeam Analysis which took place from 10-14 May 2009 in the Hotel Faltom, Gdynia, Poland. The primary aim of this series of workshops is to assess the state-of-the-art and reliability of microbeam analysis techniques. The workshops also provide a forum where students and young scientists starting out on careers in microbeam analysis can meet and discuss with the established experts. The workshops have a very distinct format comprising invited plenary lectures by internationally recognized experts, poster presentations by the participants and round table discussions on the key topics led by specialists in the field. For this workshop EMAS invited speakers on the following topics: EPMA, EBSD, fast energy-dispersive X-ray spectroscopy, three-dimensional microanalysis, and micro-and nanoanalysis in the natural resources industry. The continuing relevance of the EMAS workshops and the high regard in which they are held internationally can be seen from the fact that 69 posters from 16 countries were on display at the meeting and that the participants came from as far away as Japan and the USA. A number of participants with posters were invited to give short oral presentations of their work in two dedicated sessions. As at previous workshops there was also a special oral session for young scientists. Small cash prizes were awarded for the three best posters and for the best oral presentation by a young scientist. The prize for the best poster went to the contribution by G Tylko, S Dubchak, Z Banach and K Turnau, entitled Monte Carlo simulation for an assessment of standard validity and quantitative X-ray microanalysis in plant. Joanna Wojewoda-Budka of the Institute of Metallurgy and Materials Science, Krakow, received the prize for the best oral presentation by a

PIXE/PIGE characterisation of emeralds using an external micro-beam

International Nuclear Information System (INIS)

Calligaro, T.; Dran, J.-C.; Poirot, J.-P.; Querre, G.; Salomon, J.; Zwaan, J.C.

2000-01-01

A large collection of emeralds of various occurrences has been analysed by PIXE/PIGE in view to establish a compositional database. Major elements (Be, Si, Al) and trace elements (Li, F, Na, Mg, Ca, Rb, Cs and transition metals) are determined using an external 3 MeV proton micro-beam. Elemental micro-mapping permits to select the useful provenance tracers. This database was applied to infer the origin of several ancient emeralds set on historical jewels

Extended abstracts: Microbeam Probes of Cellular Radiation Response [final report

International Nuclear Information System (INIS)

Brenner, David J.

2000-01-01

In July 1999, we organized the 4th International Workshop: Microbeam Probes of Cellular Radiation Response, held in Killiney Bay, Dublin, Ireland, on July 17-18. Roughly 75 scientists (about equal numbers of physicists and biologists) attended the workshop, the fourth in a bi-annual series. Extended abstracts from the meeting were published in the Radiation Research journal, vol. 153, iss. 2, pp. 220-238 (February 2000)(attached). All the objectives in the proposal were met

Detection of minute strain in very local areas of materials by using an X-ray microbeam

CERN Document Server

Matsui, J; Tsusaka, Y; Kimura, S

2003-01-01

In order to analyze the local minute strain in semiconductor materials and devices, we have demonstrated formation of X-ray microbeams by using asymmetric Bragg reflections of the crystal and a zone plate or cylindrical mirror combined with synchrotron radiation. A series of X-ray rocking curves have been obtained by scanning the sample with using the X-ray microbeam. In addition, reciprocal space maps have also been obtained by inserting an analyzer crystal behind the sample. From these data, information on the strain distribution can be obtained for various samples, such as the strain near SiO sub 2 /Si film edges, that in silicon-on-insulator (SOI) crystals, and that in InGaAsP semiconductor laser stripes. (author)

High resolution X-ray fluorescence imaging for a microbeam radiation therapy treatment planning system

Science.gov (United States)

Chtcheprov, Pavel; Inscoe, Christina; Burk, Laurel; Ger, Rachel; Yuan, Hong; Lu, Jianping; Chang, Sha; Zhou, Otto

2014-03-01

Microbeam radiation therapy (MRT) uses an array of high-dose, narrow (~100 μm) beams separated by a fraction of a millimeter to treat various radio-resistant, deep-seated tumors. MRT has been shown to spare normal tissue up to 1000 Gy of entrance dose while still being highly tumoricidal. Current methods of tumor localization for our MRT treatments require MRI and X-ray imaging with subject motion and image registration that contribute to the measurement error. The purpose of this study is to develop a novel form of imaging to quickly and accurately assist in high resolution target positioning for MRT treatments using X-ray fluorescence (XRF). The key to this method is using the microbeam to both treat and image. High Z contrast media is injected into the phantom or blood pool of the subject prior to imaging. Using a collimated spectrum analyzer, the region of interest is scanned through the MRT beam and the fluorescence signal is recorded for each slice. The signal can be processed to show vascular differences in the tissue and isolate tumor regions. Using the radiation therapy source as the imaging source, repositioning and registration errors are eliminated. A phantom study showed that a spatial resolution of a fraction of microbeam width can be achieved by precision translation of the mouse stage. Preliminary results from an animal study showed accurate iodine profusion, confirmed by CT. The proposed image guidance method, using XRF to locate and ablate tumors, can be used as a fast and accurate MRT treatment planning system.

Raman Spectroscopic Study on Decorative Glasses in Thailand

International Nuclear Information System (INIS)

Won-In, K.; Ponkrapan, S.; Dararutana, P.

2011-01-01

Glasses have been used as decorative objects in Thailand for several hundred years. Decorative glasses can generally be seen as architectural components in old styled palaces and Buddhist objects. There were various colors ranging from transparent to amber, blue, green and red with different shades among glass of different colors. Fragments of archaeological glass samples were characterized for the first time using Raman microscopy with the aim of obtaining information that would lead to identification of the glass samples by means of laser scattering. The samples were also investigated using other techniques, such as particle induced X-ray emission spectroscopy and scanning electron microscope operated with energy dispersive X-ray fluorescence spectrometer. They were mostly lead-silica based glasses. The colors resulted from metal ions. The difference in chemical composition was confirmed by Raman signature spectra. (author)

Study on a noninvasive method for rapid screening Human Serum albumin injectables by Raman spectroscopy

Directory of Open Access Journals (Sweden)

Yu Zhao

2017-01-01

Full Text Available Human serum albumin (HSA injectable product is a severely afflicted area on drug safety due to its high price and restricted supply. Raman spectroscopy performances high specificity on HSA detection and it is even possible to determine HSA injectable products noninvasively. In this study, we developed a noninvasive rapid screening method for of HSA injectable products by using portable Raman spectrometer. Qualitative models were established by using principal component analysis combined with classical least squares (PCA-CLS algorithm, while quantitative model was established by using partial least squares (PLS algorithm. Model transfer in different instruments of both the same and different apparatus modules was further discussed in this paper. A total of 34 HSA injectable samples collected from markets were used for verification. The identification results showed 100% accuracy and the predicted concentrations of those identified as true HSA were consistent with their labeled concentrations. The quantitative results also indicated that model transfer was excellent in the same apparatus modules of Raman spectrometer at all concentration levels, and still good enough in the different apparatus modules although the relative standard deviation (RSD value showed a little increasing trend at low HSA concentration level. In conclusion, the method was proved to be feasible and efficient for screening HSA injections, especially on its screening speed and the consideration of glass containers. Moreover, with inspiring results on the model transfer, the method could be used as a universal screening mean to different Raman instruments.

Nitric oxide mediated bystander responses induced by microbeam targeted cells

International Nuclear Information System (INIS)

Shao, C.; Prise, K.M.; Folkard, M.; Michael, B.D.

2003-01-01

Considerable evidence has recently been accumulated in support of the existence of a 'bystander effect', which cells having received no irradiation show biological consequences from their vicinal irradiated cells. The application of microbeams is providing new insights into the radiation-induced bystander effect. The present study found that when a fraction of radioresistant human glioblastoma cells were individually targeted with a precise number of helium ions generated from the Gray Cancer Institute Charged Particle Microbeam, micronucleus (MN) induction significantly exceeded the expected value that was calculated from the number of MN observed when all of the cells were targeted assuming no bystander effect occurring. Even when only a single cell within a population was hit by one helium ion, the MN induction in the population could be increased by 16%. These results provide direct evidence of radiation-induced bystander effect. Moreover, MN was effectively induced in the unirradiated primary human fibroblasts and glioblastoma cells either co-cultured with irradiated cells or treated with the medium harvested from irradiated cells, indicating a signal molecule was produced from the irradiated cells. However, when c-PTIO, a nitric oxide (NO)-specific scavenger, was present in the medium during and after irradiation until MN analysis, the production of MN in all of the above cases was reduced to low levels. Consequently, NO plays an important role in the radiation-induced bystander effect

Digital micromirror devices in Raman trace detection of explosives

Science.gov (United States)

Glimtoft, Martin; Svanqvist, Mattias; Ågren, Matilda; Nordberg, Markus; Östmark, Henric

2016-05-01

Imaging Raman spectroscopy based on tunable filters is an established technique for detecting single explosives particles at stand-off distances. However, large light losses are inherent in the design due to sequential imaging at different wavelengths, leading to effective transmission often well below 1 %. The use of digital micromirror devices (DMD) and compressive sensing (CS) in imaging Raman explosives trace detection can improve light throughput and add significant flexibility compared to existing systems. DMDs are based on mature microelectronics technology, and are compact, scalable, and can be customized for specific tasks, including new functions not available with current technologies. This paper has been focusing on investigating how a DMD can be used when applying CS-based imaging Raman spectroscopy on stand-off explosives trace detection, and evaluating the performance in terms of light throughput, image reconstruction ability and potential detection limits. This type of setup also gives the possibility to combine imaging Raman with non-spatially resolved fluorescence suppression techniques, such as Kerr gating. The system used consists of a 2nd harmonics Nd:YAG laser for sample excitation, collection optics, DMD, CMOScamera and a spectrometer with ICCD camera for signal gating and detection. Initial results for compressive sensing imaging Raman shows a stable reconstruction procedure even at low signals and in presence of interfering background signal. It is also shown to give increased effective light transmission without sacrificing molecular specificity or area coverage compared to filter based imaging Raman. At the same time it adds flexibility so the setup can be customized for new functionality.

Abiotic versus biotic iron mineral transformation studied by a miniaturized backscattering Mössbauer spectrometer (MIMOS II), X-ray diffraction and Raman spectroscopy

Science.gov (United States)

Markovski, C.; Byrne, J. M.; Lalla, E.; Lozano-Gorrín, A. D.; Klingelhöfer, G.; Rull, F.; Kappler, A.; Hoffmann, T.; Schröder, C.

2017-11-01

Searching for biomarkers or signatures of microbial transformations of minerals is a critical aspect for determining how life evolved on Earth, and whether or not life may have existed in other planets, including Mars. In order to solve such questions, several missions to Mars have sought to determine the geochemistry and mineralogy on the Martian surface. This research includes the two miniaturized Mössbauer spectrometers (MIMOS II) on board the Mars Exploration Rovers Spirit and Opportunity, which have detected a variety of iron minerals on Mars, including magnetite (Fe2+Fe3+2O4) and goethite (α-FeO(OH)). On Earth, both minerals can derive from microbiological activity (e.g. through dissimilatory iron reduction of ferrihydrite by Fe(III)-reducing bacteria). Here we used a lab based MIMOS II to characterize the mineral products of biogenic transformations of ferrihydrite to magnetite by the Fe(III)-reducing bacteria Geobacter sulfurreducens. In combination with Raman spectroscopy and X-ray diffraction (XRD), we observed the formation of magnetite, goethite and siderite. We compared the material produced by biogenic transformations to abiotic samples in order to distinguish abiotic and biotic iron minerals by techniques that are or will be available onboard Martian based laboratories. The results showed the possibility to distinguish the abiotic and biotic origin of the minerals. Mossbauer was able to distinguish the biotic/abiotic magnetite with the interpretation of the geological context (Fe content mineral assemblages and accompanying minerals) and the estimation of the particle size in a non-destructive way. The Raman was able to confirm the biotic/abiotic principal peaks of the magnetite, as well as the organic principal vibration bands attributed to the bacteria. Finally, the XRD confirmed the particle size and mineralogy.

[Ultrastructure and Raman Spectral Characteristics of Two Kinds of Acute Myeloid Leukemia Cells].

Science.gov (United States)

Liang, Hao-Yue; Cheng, Xue-Lian; Dong, Shu-Xu; Zhao, Shi-Xuan; Wang, Ying; Ru, Yong-Xin

2018-02-01

To investigate the Raman spectral characteristics of leukemia cells from 4 patients with acute promyelocytic leukemia (M 3 ) and 3 patients with acute monoblastic leukemia (M 5 ), establish a novel Raman label-free method to distinguish 2 kinds of acute myeloid leukemia cells so as to provide basis for clinical research. Leukemia cells were collected from bone marrow of above-mentioned patients. Raman spectra were acquired by Horiba Xplora Raman spectrometer and Raman spectra of 30-50 cells from each patient were recorded. The diagnostic model was established according to principle component analysis (PCA), discriminant function analysis (DFA) and cluster analysis, and the spectra of leukemia cells from 7 patients were analyzed and classified. Characteristics of Raman spectra were analyzed combining with ultrastructure of leukemia cells. There were significant differences between Raman spectra of 2 kinds of leukemia cells. Compared with acute monoblastic leukemia cells, the spectra of acute promyelocytic leukemia cells showed stronger peaks in 622, 643, 757, 852, 1003, 1033, 1117, 1157, 1173, 1208, 1340, 1551, 1581 cm -1 . The diagnostic models established by PCA-DFA and cluster analysis could successfully classify these Raman spectra of different samples with a high accuracy of 100% (233/233). The model was evaluated by "Leave-one-out" cross-validation and reached a high accuracy of 97% (226/233). The level of macromolecules of M 3 cells is higher than that of M 5 . The diagnostic models established by PCA-DFA can classify these Raman spectra of different cells with a high accuracy. Raman spectra shows consistent result with ultrastructure by TEM.

Temperature dependence of Raman spectra of Basub(0.25)Srsub(0.75)Nbsub(2)Osub(6) crystal

International Nuclear Information System (INIS)

Rustamov, Kh.Sh.; Gorelik, V.S.; Kuz'minov, Yu.S.; Peregudov, G.V.; Sushchinskij, M.M.

1976-01-01

The nature of the changes is studied in the Raman spectra in a crystal of Basub(x)Srsub(1-x)Nasub(2)Osub(6) (x=0.25) with the temperature range of 80 to 373 K. Normal procedure was applied with the use of an argon laser (Λ=4880 A) and a DFS-12 spectrometer. It has been established that at low temperatures the spectrum becomes more clear-cut; in the low-frequency range some sharp lines appear in the immediate vicinity of the exciting line. On heating of the crystal one observes a redistribution of the intensity in the Raman spectrum and a general displacement of the low-frequency Raman spectrum and a general displacement of the low-frequency Raman spectrum toward the exciting line. The nature of the frequency shifts some Raman maxima was investigated, and certain anomalies were observed in the vicinity of the phase transition point

Analysis of the X-ray microbeam test result of the flash memories

International Nuclear Information System (INIS)

Yan Yihua; Ding Lili; Chen Wei; Guo Hongxia; Guo Xiaoqiang; Lin Dongsheng; Zhang Keying; Zhang Fengqi; Deng Yuliang; Fan Ruyu

2013-01-01

Background: The failure phenomenon is difficult to analyze for the flash memories when the whole chip is exposed to irradiation since both the memory array and the peripheral circuits might be degraded. Purpose: In order to detect the radiation susceptibility and corresponding phenomenon of the related circuits that included in the flash memories, the X-ray microbeam is used as the radiation source instead of 60 Co. Methods: The failure phenomenon is studied respectively when the memory array, decoder circuits, the charge pump circuits as well as the I/O circuits are exposed to radiation. The errors are mapped according to the logical address and the failure mechanism is analyzed based on the circuits. Results: Irradiated on the memory .array win lead to regularly distributed 0→1 bit flips, while only 1→0 are found when the row decoder is under exposure. Degradation of the charge pump circuits would lead to the erase/program functional failure. Conclusions: The results suggest that the X-ray microbeam radiation test is a good method for detecting the radiation susceptibility of the integrated circuits that contains lots of circuit modules. (authors)

Raman Investigation of Temperature Profiles of Phospholipid Dispersions in the Biochemistry Laboratory

Science.gov (United States)

Craig, Norman C.

2015-06-01

The temperature dependence of self-assembled, cell-like dispersions of phospholipids is investigated with Raman spectroscopy in the biochemistry laboratory. Vibrational modes in the hydrocarbon interiors of phospholipid bilayers are strongly Raman active, whereas the vibrations of the polar head groups and the water matrix have little Raman activity. From Raman spectra increases in fluidity of the hydrocarbon chains can be monitored with intensity changes as a function of temperature in the CH-stretching region. The experiment uses detection of scattered 1064-nm laser light (Nicolet NXR module) by a Fourier transform infrared spectrometer (Nicolet 6700). A thermoelectric heater-cooler device (Melcor) gives convenient temperature control from 5 to 95°C for samples in melting point capillaries. Use of deuterium oxide instead of water as the matrix avoids some absorption of the exciting laser light and interference with intensity observations in the CH-stretching region. Phospholipids studied range from dimyristoylphosphotidyl choline (C14, transition T = 24°C) to dibehenoylphosphotidyl choline (C22, transition T = 74°C).

Free vibration analysis of magneto-electro-elastic microbeams subjected to magneto-electric loads

Science.gov (United States)

Vaezi, Mohamad; Shirbani, Meisam Moory; Hajnayeb, Ali

2016-01-01

Different types of actuating and sensing mechanisms are used in new micro and nanoscale devices. Therefore, a new challenge is modeling electromechanical systems that use these mechanisms. In this paper, free vibration of a magnetoelectroelastic (MEE) microbeam is investigated in order to obtain its natural frequencies and buckling loads. The beam is simply supported at both ends. External electric and magnetic potentials are applied to the beam. By using the Hamilton's principle, the governing equations and boundary conditions are derived based on the Euler-Bernoulli beam theory. The equations are solved, analytically to obtain the natural frequencies of the MEE microbeam. Furthermore, the effects of external electric and magnetic potentials on the buckling of the beam are analyzed and the critical values of the potentials are obtained. Finally, a numerical study is conducted. It is found that the natural frequency can be tuned directly by changing the magnetic and electric potentials. Additionally, a closed form solution for the normalized natural frequency is derived, and buckling loads are calculated in a numerical example.

Diagnosing basal cell carcinoma in vivo by near-infrared Raman spectroscopy: a Principal Components Analysis discrimination algorithm

Science.gov (United States)

Silveira, Landulfo, Jr.; Silveira, Fabrício L.; Bodanese, Benito; Pacheco, Marcos Tadeu T.; Zângaro, Renato A.

2012-02-01

This work demonstrated the discrimination among basal cell carcinoma (BCC) and normal human skin in vivo using near-infrared Raman spectroscopy. Spectra were obtained in the suspected lesion prior resectional surgery. After tissue withdrawn, biopsy fragments were submitted to histopathology. Spectra were also obtained in the adjacent, clinically normal skin. Raman spectra were measured using a Raman spectrometer (830 nm) with a fiber Raman probe. By comparing the mean spectra of BCC with the normal skin, it has been found important differences in the 800-1000 cm-1 and 1250-1350 cm-1 (vibrations of C-C and amide III, respectively, from lipids and proteins). A discrimination algorithm based on Principal Components Analysis and Mahalanobis distance (PCA/MD) could discriminate the spectra of both tissues with high sensitivity and specificity.

Heavy Ion Microbeam- and Broadbeam-Induced Transients in SiGe HBTs

Science.gov (United States)

Pellish, Jonathan A.; Reed, Robert A.; McMorrow, Dale; Vizkelethy, Gyorgy; Ferlet-Cavrois, Veronique; Baggio, Jacques; Duhamel, Olivier; Moen, Kurt A.; Phillips, Stanley D.; Diestelhorst, Ryan M.;

The Columbia University microbeam II endstation for cell imaging and irradiation

International Nuclear Information System (INIS)

Bigelow, A.W.; Ross, G.J.; Randers-Pehrson, G.; Brenner, D.J.

2005-01-01

The Columbia University Microbeam II has been built to provide a focused ion beam for irradiating designated mammalian cells with single particles. With the interest in irradiating non-stained cells and cells in three-dimensional tissue samples, the endstation was designed to accommodate a variety of imaging techniques, in addition to fluorescent microscopy. Non-stained cells are imaged either by quantitative phase microscopy (QPm) [IATIA, Box Hill North, Victoria, 3129, Australia [1

Preliminary application of tapered glass capillary microbeam in MeV-PIXE mapping of longan leaf for elemental concentration distribution analysis

Science.gov (United States)

Natyanun, S.; Unai, S.; Yu, L. D.; Tippawan, U.; Pussadee, N.

2017-09-01

This study was aimed at understanding elemental concentration distribution in local longan leaf for how the plant was affected by the environment or agricultural operation. The analysis applied the MeV-microbeam particle induced X-ray emission (PIXE) mapping technique using a home-developed tapered glass capillary microbeam system at Chiang Mai University. The microbeam was 2-MeV proton beam in 130 µm in diameter. The studying interest was in the difference in the elemental concentrations distributed between the leaf midrib and lamina areas. The micro proton beam analyzed the leaf sample across the leaf midrib edge to the leaf lamina area for total 9 data requisition spots. The resulting data were colored to form a 1D-map of the elemental concentration distribution. Seven dominant elements, Al, S, Cl, K, Ca, Sc and Fe, were identified, the first six of which were found having higher concentrations in the midrib area than in the lamina area, while the Fe concentration was in an opposite trend to that of the others.

Beam Characterisation of the Australian Synchrotron Imaging and medical beamline for microbeam radiotherapy research

International Nuclear Information System (INIS)

Gagliardi, F.M.; Midgley, S.; Lewis, R.A.; Ackerly, T.L.

2010-01-01

Full text: Microbeam radiotherapy (MRT) has been developed at synchrotrons around the world over the last two decades. Previous studies have shown normal tissue to be extremely tolerant to MRT at doses normally considered toxic in conventional radiotherapy whilst having a palliative and even curative effect on animal tumours. Our MRT research team has attempted to characterise the beam spectrum of the imaging and medical beamline (TMBL) at the Australian Synchrotron. We also carried out film dosimetry to quantify the peak-to-valley dose ratio for three fixed geometry MRT collimators. The source of X-rays on the IMBL is a 1.4 T wiggler at a distance of 20 m from the sample stage. In vacuo and in-air metal absorbers were used to remove soft X-rays hardening the beam to between 30 and 160 keY. Filters used were 1.5 mm C, 2.5 mm AI, 0.5 mm Be and 0.75 mm Cu. Free air ion chamber measurements and half value layer measurements in conjunction with predictions from a theoretical model based upon a spectrum calculator derived a mean energy of the microbeam of 57 keV with a half value layer of approximately 0.29 mm Cu. The measured air kerma rate was 120 Gy/s. Measurements of the MRT beams created with tungsten/kapton multi-slit collimators on radiographic films were compared with Monte Carlo simulations of the microbeam arrays. The peak-to-valley-dose ratios were found to be 3-4 times lower than predicted by the Monte Carlo model. Imperfections in the manufacturing of the collimators may explain the observed discrepancy. (author)

MeV He microbeam analysis of a semiconductor integrated circuit

International Nuclear Information System (INIS)

Zhu Peiran; Liu Jiarui; Zhang Jinping; Yin Shiduan

1989-01-01

An MeV He + microbeam has been used to analyse a microscale semiconductor structure. The 2 MeV He + ion beam is limited to 25 μm diameter by a set of diaphragms and is further focused by a quadrupole quadruplet to 3μm diameter. The incident beam current on the sample is about 0.3 nA. The Rutherford backscattering (RBS) technique is applied to the measurement of the composition and depth profile in the near-surface region of a semiconductor integrated circuit. (author)

MeV He microbeam analysis of a semiconductor integrated circuit

Energy Technology Data Exchange (ETDEWEB)

Zhu Peiran; Liu Jiarui; Zhang Jinping; Yin Shiduan

1989-01-01

An MeV He/sup +/ microbeam has been used to analyse a microscale semiconductor structure. The 2 MeV He/sup +/ ion beam is limited to 25 /mu/m diameter by a set of diaphragms and is further focused by a quadrupole quadruplet to 3/mu/m diameter. The incident beam current on the sample is about 0.3 nA. The Rutherford backscattering (RBS) technique is applied to the measurement of the composition and depth profile in the near-surface region of a semiconductor integrated circuit.

An automated single ion hit at JAERI heavy ion microbeam to observe individual radiation damage

International Nuclear Information System (INIS)

Kamiya, Tomihiro; Sakai, Takuro; Naitoh, Yutaka; Hamano, Tsuyoshi; Hirao, Toshio

1999-01-01

Microbeam scanning and a single ion hit technique have been combined to establish an automated beam positioning and single ion hit system at the JAERI Takasaki heavy ion microbeam system. Single ion irradiation on preset points of a sample in various patterns can be performed automatically in a short period. The reliability of the system was demonstrated using CR-39 nuclear track detectors. Single ion hit patterns were achieved with a positioning accuracy of 2 μm or less. In measurement of single event transient current using this system, the reduction of the pulse height by accumulation of radiation damages was observed by single ion injection to the same local areas. This technique showed a possibility to get some quantitative information about the lateral displacement of an individual radiation effect in silicon PIN photodiodes. This paper will give details of the irradiation system and present results from several experiments

Correlated microradiography, X-ray microbeam diffraction and electron probe microanalysis of calcifications in an odontoma

International Nuclear Information System (INIS)

Aoba, T.; Yoshioka, C.; Yagi, T.

1980-01-01

Using microradiography, X-ray microbeam diffraction and electron probe microanalysis, a correlated morphologic and crystallographic study was performed on dysplastic enamel in a compound odontoma. The tumor was found in the lateral incisor-canine region of the left mandible of a 36-year-old woman. A conspicuous feature was the presence of hypomineralized areas, which were situated in the proximity of enamel surface and distinctly demarcated from the adjacent enamel. X-ray microbeam diffraction and electron microanalysis showed that these lesions have a lower crystallinity and a higher concentration of magnesium as compared with the adjacent enamel. In addition, the present study revealed the presence of two other types of calcifications: 1) calcified structures within the fissure or on the enamel surface, which include lacunae of varying size and which resemble a form of coronal cementum, and 2) spherical calcifications which may be an epithelial product. (author)

Dual-Remote Raman Technology for In-Situ Identification of Tank Waste - 13549

International Nuclear Information System (INIS)

Bryan, Sam; Levitskaia, Tatiana; Lines, Amanda; Smith, Frannie; Josephson, Gary; Bello, Job

2013-01-01

A new Raman spectroscopic system for in-situ identification of the composition of solid nuclear tank waste is being developed by collaborative effort between Pacific Northwest National Laboratory (PNNL) and EIC Laboratories, Inc. The recent advancements in Raman technology allow probing the chemical composition of the tank waste without sample collection. In the newly tested configuration, the Raman probe is installed on the top of the tank riser and sends the incident laser beam to the bottom of the tank, 10 - 70 feet away. The returning light containing chemical information is collected by the Raman probe and is transmitted via fiber optic cable to the spectrometer located outside the tank farm area. This dual remote technology significantly expands currently limited options for the safe rapid in-situ identification of the solid tank waste needed for the retrieval decisions. The developed Raman system was extensively tested for acceptability prior to tank farm deployment. This testing included calibration of the system with respect of the distance between the Raman probe and the sample, incident laser beam angle, and presence of the optical interferences. The Raman system was successfully deployed on Tank C-111 at the US DOE Hanford site. As the result of this deployment, the composition of the hardpan at the bottom of C-111 tank was identified. Further development of the dual-remote Raman technology will provide a significant safety enhancement eliminating the potential of personnel radiation exposure associated with the grab sample collection and expands options of the rapid and cost-effective in-situ chemical analysis of the tank waste. (authors)

Investigation of chemical vapour deposition diamond detectors by X-ray micro-beam induced current and X-ray micro-beam induced luminescence techniques

International Nuclear Information System (INIS)

Olivero, P.; Manfredotti, C.; Vittone, E.; Fizzotti, F.; Paolini, C.; Lo Giudice, A.; Barrett, R.; Tucoulou, R.

2004-01-01

Tracking detectors have become an important ingredient in high-energy physics experiments. In order to survive the harsh detection environment of the large hadron collider (LHC), trackers need to have special properties. They must be radiation hard, provide fast collection of charge, be as thin as possible and remove heat from readout electronics. The unique properties of diamond allow it to fulfill these requirements. In this work we present an investigation of the charge transport and luminescence properties of 'detector grade' artificial chemical vapour deposition (CVD) diamond devices developed within the CERN RD42 collaboration, performed by means of X-ray micro-beam induced current collection (XBICC) and X-ray micro-beam induced luminescence (XBIL) techniques. XBICC technique allows quantitative estimates of the transport parameters of the material to be evaluated and mapped with micrometric spatial resolution. In particular, the high resolution and sensitivity of the technique has allowed a quantitative study of the inhomogeneity of the charge transport parameter defined as the product of mobility and lifetime for both electron and holes. XBIL represents a technique complementary to ion beam induced luminescence (IBIL), which has already been used by our group, since X-ray energy loss profile in the material is different from that of MeV ions. X-ray induced luminescence maps have been performed simultaneously with induced photocurrent maps, to correlate charge transport and induced luminescence properties of diamond. Simultaneous XBICC and XBIL maps exhibit features of partial complementarity that have been interpreted on the basis of considerations on radiative and non-radiative recombination processes which compete with charge transport efficiency

In Situ Raman Analyses of Natural Gas and Gas Hydrates at Hydrate Ridge, Oregon

Science.gov (United States)

Peltzer, E. T.; White, S. N.; Dunk, R. M.; Brewer, P. G.; Sherman, A. D.; Schmidt, K.; Hester, K. C.; Sloan, E. D.

2004-12-01

During a July 2004 cruise to Hydrate Ridge, Oregon, MBARI's sea-going laser Raman spectrometer was used to obtain in situ Raman spectra of natural gas hydrates and natural gas venting from the seafloor. This was the first in situ analysis of gas hydrates on the seafloor. The hydrate spectra were compared to laboratory analyses performed at the Center for Hydrate Research, Colorado School of Mines. The natural gas spectra were compared to MBARI gas chromatography (GC) analyses of gas samples collected at the same site. DORISS (Deep Ocean Raman In Situ Spectrometer) is a laboratory model laser Raman spectrometer from Kaiser Optical Systems, Inc modified at MBARI for deployment in the deep ocean. It has been successfully deployed to depths as great as 3600 m. Different sampling optics provide flexibility in adapting the instrument to a particular target of interest. An immersion optic was used to analyze natural gas venting from the seafloor at South Hydrate Ridge ( ˜780 m depth). An open-bottomed cube was placed over the vent to collect the gas. The immersion optic penetrated the side of the cube as did a small heater used to dissociate any hydrate formed during sample collection. To analyze solid hydrates at both South and North Hydrate Ridge ( ˜590 m depth), chunks of hydrate were excavated from the seafloor and collected in a glass cylinder with a mesh top. A stand-off optic was used to analyze the hydrate inside the cylinder. Due to the partial opacity of the hydrate and the small focal volume of the sampling optic, a precision underwater positioner (PUP) was used to focus the laser spot onto the hydrate. PUP is a stand-alone system with three degrees-of-freedom, capable of moving the DORISS probe head with a precision of 0.1 mm. In situ Raman analyses of the gas indicate that it is primarily methane. This is verified by GC analyses of samples collected from the same site. Other minor constituents (such as CO2 and higher hydrocarbons) are present but may be in

Fragmentation of neutral van der Waals clusters with visible laser light: A new variant of the Raman effect?

International Nuclear Information System (INIS)

Stamatovic, A.; Howorka, F.; Scheier, P.; Maerk, T.D.

1989-01-01

We have observed strong photodissociation (using visible laser light) of neutral van der Waals clusters (Ar, N 2 , O 2 , CO 2 , SO 2 , NH 3 ) produced by supersonic expansion and detected by electron ionization/mass spectrometer. Several tests were performed, all of them supporting this surprising discovery. We suggest that Raman induced photodissociation (RIP) is responsible for this phenomenon. This first observation of Raman induced photodissociation provides a new technique for the study of neutral van der Waals clusters. (orig.)

Raman spectroscopy and oral exfoliative cytology

Science.gov (United States)

Sahu, Aditi; Shah, Nupur; Mahimkar, Manoj; Garud, Mandavi; Pagare, Sandeep; Nair, Sudhir; Krishna, C. Murali

2014-03-01

Early detection of oral cancers can substantially improve disease-free survival rates. Ex vivo and in vivo Raman spectroscopic (RS) studies on oral cancer have demonstrated the applicability of RS in identifying not only malignant and premalignant conditions but also cancer-field-effects: the earliest events in oral carcinogenesis. RS has also been explored for cervical exfoliated cells analysis. Exfoliated cells are associated with several advantages like non-invasive sampling, higher patient compliance, transportation and analysis at a central facility: obviating need for on-site instrumentation. Thus, oral exfoliative cytology coupled with RS may serve as a useful adjunct for oral cancer screening. In this study, exfoliated cells from healthy controls with and without tobacco habits, premalignant lesions (leukoplakia and tobacco-pouch-keratosis) and their contralateral mucosa were collected using a Cytobrush. Cells were harvested by vortexing and centrifugation at 6000 rpm. The cellular yield was ascertained using Neubauer's chamber. Cell pellets were placed on a CaF2 window and Raman spectra were acquired using a Raman microprobe (40X objective) coupled HE-785 Raman spectrometer. Approximately 7 spectra were recorded from each pellet, following which pellet was smeared onto a glass slide, fixed in 95% ethanol and subjected to Pap staining for cytological diagnosis (gold standard). Preliminary PC-LDA followed by leave-one-out cross validation indicate delineation of cells from healthy and all pathological conditions. A tendency of classification was also seen between cells from contralateral, healthy tobacco and site of premalignant lesions. These results will be validated by cytological findings, which will serve as the basis for building standard models of each condition.

Raman spectroscopy of triolein under high pressures

Science.gov (United States)

Tefelski, D. B.; Jastrzębski, C.; Wierzbicki, M.; Siegoczyński, R. M.; Rostocki, A. J.; Wieja, K.; Kościesza, R.

2010-03-01

This article presents results of the high pressure Raman spectroscopy of triolein. Triolein, a triacylglyceride (TAG) of oleic acid, is an unsaturated fat, present in natural oils such as olive oil. As a basic food component and an energy storage molecule, it has considerable importance for food and fuel industries. To generate pressure in the experiment, we used a high-pressure cylindrical chamber with sapphire windows, presented in (R.M. Siegoczyński, R. Kościesza, D.B. Tefelski, and A. Kos, Molecular collapse - modification of the liquid structure induced by pressure in oleic acid, High Press. Res. 29 (2009), pp. 61-66). Pressure up to 750 MPa was applied. A Raman spectrometer in "macro"-configuration was employed. Raman spectroscopy provides information on changes of vibrational modes related to structural changes of triolein under pressure. Interesting changes in the triglyceride C‒H stretching region at 2650-3100 cm-1 were observed under high-pressures. Changes were also observed in the ester carbonyl (C˭ O) stretching region 1700-1780 cm-1 and the C‒C stretching region at 1050-1150 cm-1. The overall luminescence of the sample decreased under pressure, making it possible to set longer spectrum acquisition time and obtain more details of the spectrum. The registered changes suggest that the high-pressure solid phase of triolein is organized as β-polymorphic, as was reported in (C. Akita, T. Kawaguchi, and F. Kaneko, Structural study on polymorphism of cis-unsaturated triacylglycerol: Triolein, J. Phys. Chem. B 110 (2006), pp. 4346-4353; E. Da Silva and D. Rousseau, Molecular order and thermodynamics of the solid-liquid transition in triglycerides via Raman spectroscopy, Phys. Chem. Chem. Phys. 10 (2008), pp. 4606-4613) (with temperature-induced phase transitions). The research has shown that Raman spectroscopy in TAGs under pressure reveals useful information about its structural changes.

Note: A portable Raman analyzer for microfluidic chips based on a dichroic beam splitter for integration of imaging and signal collection light paths

Energy Technology Data Exchange (ETDEWEB)

Geng, Yijia; Xu, Shuping; Xu, Weiqing, E-mail: xuwq@jlu.edu.cn [State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, Jilin University, Changchun 130012 (China); Chen, Lei [State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, Jilin University, Changchun 130012 (China); College of Physics, Jilin University, Changchun 130012 (China); Chen, Gang [State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, Jilin University, Changchun 130012 (China); College of Chemistry, Jilin University, Changchun 130012 (China); Bi, Wenbin [State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, Jilin University, Changchun 130012 (China); School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, Changchun 130022 (China); Cui, Haining [College of Physics, Jilin University, Changchun 130012 (China)

2015-05-15

An integrated and portable Raman analyzer featuring an inverted probe fixed on a motor-driving adjustable optical module was designed for the combination of a microfluidic system. It possesses a micro-imaging function. The inverted configuration is advantageous to locate and focus microfluidic channels. Different from commercial micro-imaging Raman spectrometers using manual switchable light path, this analyzer adopts a dichroic beam splitter for both imaging and signal collection light paths, which avoids movable parts and improves the integration and stability of optics. Combined with surface-enhanced Raman scattering technique, this portable Raman micro-analyzer is promising as a powerful tool for microfluidic analytics.

On using the dynamic snap-through motion of MEMS initially curved microbeams for filtering applications

KAUST Repository

Ouakad, Hassen M.; Younis, Mohammad I.

2014-01-01

Numerical and experimental investigations of the dynamics of micromachined shallow arches (initially curved microbeams) and the possibility of using their dynamic snap-through motion for filtering purposes are presented. The considered MEMS arches are actuated by a DC electrostatic load along with an AC harmonic load. Their dynamics is examined numerically using a Galerkin-based reduced-order model when excited near both their first and third natural frequencies. Several simulation results are presented demonstrating interesting jumps and dynamic snap-through behavior of the MEMS arches and their attractive features for uses as band-pass filters, such as their sharp roll-off from pass-bands to stop-bands and their flat response. Experimental work is conducted to test arches realized of curved polysilicon microbeams when excited by DC and AC loads. Experimental data of the micromachined curved beams are shown for the softening and hardening behavior near the first and third natural frequencies, respectively, as well as dynamic snap-through motion. © 2013 Elsevier Ltd.

In vivo Raman spectroscopy of cervix cancers

Science.gov (United States)

Rubina, S.; Sathe, Priyanka; Dora, Tapas Kumar; Chopra, Supriya; Maheshwari, Amita; Krishna, C. Murali

2014-03-01

Cervix-cancer is the third most common female cancer worldwide. It is the leading cancer among Indian females with more than million new diagnosed cases and 50% mortality, annually. The high mortality rates can be attributed to late diagnosis. Efficacy of Raman spectroscopy in classification of normal and pathological conditions in cervix cancers on diverse populations has already been demonstrated. Our earlier ex vivo studies have shown the feasibility of classifying normal and cancer cervix tissues as well as responders/non-responders to Concurrent chemoradiotherapy (CCRT). The present study was carried out to explore feasibility of in vivo Raman spectroscopic methods in classifying normal and cancerous conditions in Indian population. A total of 182 normal and 132 tumor in vivo Raman spectra, from 63 subjects, were recorded using a fiberoptic probe coupled HE-785 spectrometer, under clinical supervision. Spectra were acquired for 5 s and averaged over 3 times at 80 mW laser power. Spectra of normal conditions suggest strong collagenous features and abundance of non-collagenous proteins and DNA in case of tumors. Preprocessed spectra were subjected to Principal Component-Linear Discrimination Analysis (PCLDA) followed by leave-one-out-cross-validation. Classification efficiency of ~96.7% and 100% for normal and cancerous conditions respectively, were observed. Findings of the study corroborates earlier studies and suggest applicability of Raman spectroscopic methods in combination with appropriate multivariate tool for objective, noninvasive and rapid diagnosis of cervical cancers in Indian population. In view of encouraging results, extensive validation studies will be undertaken to confirm the findings.

Large deformation of uniaxially loaded slender microbeams on the basis of modified couple stress theory: Analytical solution and Galerkin-based method

Science.gov (United States)

Kiani, Keivan

2017-09-01

Large deformation regime of micro-scale slender beam-like structures subjected to axially pointed loads is of high interest to nanotechnologists and applied mechanics community. Herein, size-dependent nonlinear governing equations are derived by employing modified couple stress theory. Under various boundary conditions, analytical relations between axially applied loads and deformations are presented. Additionally, a novel Galerkin-based assumed mode method (AMM) is established to solve the highly nonlinear equations. In some particular cases, the predicted results by the analytical approach are also checked with those of AMM and a reasonably good agreement is reported. Subsequently, the key role of the material length scale on the load-deformation of microbeams is discussed and the deficiencies of the classical elasticity theory in predicting such a crucial mechanical behavior are explained in some detail. The influences of slenderness ratio and thickness of the microbeam on the obtained results are also examined. The present work could be considered as a pivotal step in better realizing the postbuckling behavior of nano-/micro- electro-mechanical systems consist of microbeams.

Determination of human coronary artery composition by Raman spectroscopy.

Science.gov (United States)

Brennan, J F; Römer, T J; Lees, R S; Tercyak, A M; Kramer, J R; Feld, M S

1997-07-01

We present a method for in situ chemical analysis of human coronary artery using near-infrared Raman spectroscopy. It is rapid and accurate and does not require tissue removal; small volumes, approximately 1 mm3, can be sampled. This methodology is likely to be useful as a tool for intravascular diagnosis of artery disease. Human coronary artery segments were obtained from nine explanted recipient hearts within 1 hour of heart transplantation. Minces from one or more segments were obtained through grinding in a mortar and pestle containing liquid nitrogen. Artery segments and minces were excited with 830 nm near-infrared light, and Raman spectra were collected with a specially designed spectrometer. A model was developed to analyze the spectra and quantify the amounts of cholesterol, cholesterol esters, triglycerides and phospholipids, and calcium salts present. The model provided excellent fits to spectra from the artery segments, indicating its applicability to intact tissue. In addition, the minces were assayed chemically for lipid and calcium salt content, and the results were compared. The relative weights obtained using the Raman technique agreed with those of the standard assays within a few percentage points. The chemical composition of coronary artery can be quantified accurately with Raman spectroscopy. This opens the possibility of using histochemical analysis to predict acute events such as plaque rupture, to follow the progression of disease, and to select appropriate therapeutic interventions.

In situ macromolecular crystallography using microbeams.

Science.gov (United States)

Axford, Danny; Owen, Robin L; Aishima, Jun; Foadi, James; Morgan, Ann W; Robinson, James I; Nettleship, Joanne E; Owens, Raymond J; Moraes, Isabel; Fry, Elizabeth E; Grimes, Jonathan M; Harlos, Karl; Kotecha, Abhay; Ren, Jingshan; Sutton, Geoff; Walter, Thomas S; Stuart, David I; Evans, Gwyndaf

2012-05-01

Despite significant progress in high-throughput methods in macromolecular crystallography, the production of diffraction-quality crystals remains a major bottleneck. By recording diffraction in situ from crystals in their crystallization plates at room temperature, a number of problems associated with crystal handling and cryoprotection can be side-stepped. Using a dedicated goniometer installed on the microfocus macromolecular crystallography beamline I24 at Diamond Light Source, crystals have been studied in situ with an intense and flexible microfocus beam, allowing weakly diffracting samples to be assessed without a manual crystal-handling step but with good signal to noise, despite the background scatter from the plate. A number of case studies are reported: the structure solution of bovine enterovirus 2, crystallization screening of membrane proteins and complexes, and structure solution from crystallization hits produced via a high-throughput pipeline. These demonstrate the potential for in situ data collection and structure solution with microbeams. © 2012 International Union of Crystallography

Characterization and quantification of cerebral edema induced by synchrotron x-ray microbeam radiation therapy

Energy Technology Data Exchange (ETDEWEB)

Serduc, Raphael; Looij, Yohan van de; Francony, Gilles; Verdonck, Olivier; Sanden, Boudewijn van der; Farion, Regine; Segebarth, Christoph; Remy, Chantal; Lahrech, Hana [INSERM, U836, F-38043 Grenoble (France); Laissue, Jean [Institute of Pathology, University of Bern (Switzerland); Braeuer-Krisch, Elke; Siegbahn, Erik Albert; Bravin, Alberto; Prezado, Yolanda [European Synchrotron Radiation Facility, F-38043 Grenoble (France)], E-mail: serduc@esrf.fr

2008-03-07

Cerebral edema is one of the main acute complications arising after irradiation of brain tumors. Microbeam radiation therapy (MRT), an innovative experimental radiotherapy technique using spatially fractionated synchrotron x-rays, has been shown to spare radiosensitive tissues such as mammal brains. The aim of this study was to determine if cerebral edema occurs after MRT using diffusion-weighted MRI and microgravimetry. Prone Swiss nude mice's heads were positioned horizontally in the synchrotron x-ray beam and the upper part of the left hemisphere was irradiated in the antero-posterior direction by an array of 18 planar microbeams (25 mm wide, on-center spacing 211 mm, height 4 mm, entrance dose 312 Gy or 1000 Gy). An apparent diffusion coefficient (ADC) was measured at 7 T 1, 7, 14, 21 and 28 days after irradiation. Eventually, the cerebral water content (CWC) was determined by microgravimetry. The ADC and CWC in the irradiated (312 Gy or 1000 Gy) and in the contralateral non-irradiated hemispheres were not significantly different at all measurement times, with two exceptions: (1) a 9% ADC decrease (p < 0.05) was observed in the irradiated cortex 1 day after exposure to 312 Gy, (2) a 0.7% increase (p < 0.05) in the CWC was measured in the irradiated hemispheres 1 day after exposure to 1000 Gy. The results demonstrate the presence of a minor and transient cellular edema (ADC decrease) at 1 day after a 312 Gy exposure, without a significant CWC increase. One day after a 1000 Gy exposure, the CWC increased, while the ADC remained unchanged and may reflect the simultaneous presence of cellular and vasogenic edema. Both types of edema disappear within a week after microbeam exposure which may confirm the normal tissue sparing effect of MRT. For more information on this article, see medicalphysicsweb.org.

In vivo confocal Raman spectroscopy of the human cornea.

Science.gov (United States)

Bauer, N J; Hendrikse, F; March, W F

1999-07-01

To investigate the feasibility of a confocal Raman spectroscopic technique for the noninvasive assessment of corneal hydration in vivo in two legally blind subjects. A laser beam (632.8 nm; 15 mJ) was maintained on the cornea by using a microscope objective lens (x25 magnification, NA = 0.5, f = 10 mm) both for focusing the incident light as well as collecting the Raman backscattered light, in a 180 degrees backscatter configuration. An optical fiber, acting as the confocal pinhole for elimination of light from out-of-focus places, was coupled to a spectrometer that dispersed the collected light onto a sensitive array detector for rapid spectral data acquisition over a range from 2,890 to 3,590/cm(-1). Raman spectra were recorded from the anterior 100-150 microm of the cornea over a period before and after topical application of a mild dehydrating solution. The ratio between the amplitudes of the signals at 3,400/cm(-1) (OH-vibrational mode of water) and 2,940/cm(-1) (CH-vibrational mode of proteins) was used as a measure for corneal hydration. High signal-to-noise ratio (SNR = 25) Raman spectra were obtained from the human corneas by using 15 mJ of laser light energy. Qualitative changes in the hydration of the anteriormost part of the corneas could be observed as a result of the dehydrating agent. With adequate improvements in system safety, confocal Raman spectroscopy could potentially be applied clinically as a noninvasive tool for the assessment of corneal hydration in vivo.

Blueberry juices: a rapid multi-analysis of quality indicators by means of dispersive Raman spectroscopy excited at 1064 nm

Science.gov (United States)

Ciaccheri, L.; Yuan, T.; Zhang, S.; Mencaglia, A. A.; Trono, C.; Yuan, L.; Mignani, A. G.

2017-04-01

Blueberry juices produced in China and in Italy were analyzed by means of Raman spectroscopy. The reference data of important nutraceutical indicators such as degrees Brix and carbohydrates were available. Some juices were produced from fresh organic fruits, while others were industrial grade, differing in qualities and prices. Raman spectra obtained with excitation at 1064 nm were acquired using a dispersive fiber-optic spectrometer. Degrees Brix were measured by means of a commercial refractometer, while carbohydrate contents were available from the producers. Multivariate processing was used for predicting Brix and carbohydrates from Raman spectra and from the reference data. Determination coefficients equal to 0.88 and 0.84, respectively, were obtained. This experiment further confirms the excellent potentials of Raman spectroscopy for both non-destructive and rapid assessments of food quality.

Identification of ancient textile fibres from Khirbet Qumran caves using synchrotron radiation microbeam diffraction

Energy Technology Data Exchange (ETDEWEB)

Mueller, Martin [Institut fuer Experimentelle und Angewandte Physik der Christian, Albrechts, Universitaet zu Kiel, Leibnizstr. 19, D-24098 Kiel (Germany)]. E-mail: mmueller@physik.uni-kiel.de; Murphy, Bridget [Institut fuer Experimentelle und Angewandte Physik der Christian, Albrechts, Universitaet zu Kiel, Leibnizstr. 19, D-24098 Kiel (Germany); Burghammer, Manfred [European Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble Cedex (France); Riekel, Christian [European Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble Cedex (France); Roberts, Mark [Daresbury Laboratory, Keckwick Lane, Warrington WA4 4AD (United Kingdom); Papiz, Miroslav [Daresbury Laboratory, Keckwick Lane, Warrington WA4 4AD (United Kingdom); Clarke, David [Daresbury Laboratory, Keckwick Lane, Warrington WA4 4AD (United Kingdom); Gunneweg, Jan [Institute of Archaeology, The Hebrew University of Jerusalem, Mount Scopus, Jerusalem (Israel); Pantos, Emmanuel [Daresbury Laboratory, Keckwick Lane, Warrington WA4 4AD (United Kingdom)

2004-10-08

Archaeological textiles fragments from the caves of Qumran in the Dead Sea region were investigated by means of X-ray microbeam diffraction on single fibres. This non-destructive technique made the identification of the used plant textile fibres possible. Apart from bast fibres (mainly flax), cotton was identified which was most unexpected in the archaeological context.

Identification of ancient textile fibres from Khirbet Qumran caves using synchrotron radiation microbeam diffraction

International Nuclear Information System (INIS)

Mueller, Martin; Murphy, Bridget; Burghammer, Manfred; Riekel, Christian; Roberts, Mark; Papiz, Miroslav; Clarke, David; Gunneweg, Jan; Pantos, Emmanuel

2004-01-01

Archaeological textiles fragments from the caves of Qumran in the Dead Sea region were investigated by means of X-ray microbeam diffraction on single fibres. This non-destructive technique made the identification of the used plant textile fibres possible. Apart from bast fibres (mainly flax), cotton was identified which was most unexpected in the archaeological context

Identification of ancient textile fibres from Khirbet Qumran caves using synchrotron radiation microbeam diffraction

Science.gov (United States)

Müller, Martin; Murphy, Bridget; Burghammer, Manfred; Riekel, Christian; Roberts, Mark; Papiz, Miroslav; Clarke, David; Gunneweg, Jan; Pantos, Emmanuel

2004-10-01

Archaeological textiles fragments from the caves of Qumran in the Dead Sea region were investigated by means of X-ray microbeam diffraction on single fibres. This non-destructive technique made the identification of the used plant textile fibres possible. Apart from bast fibres (mainly flax), cotton was identified which was most unexpected in the archaeological context.

Searching for brine on Mars using Raman spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Fischer, E.

2016-07-01

In the last few years, water ice and perchlorate salts capable of melting this ice and producing liquid solutions have been discovered at the surface and shallow subsurface of Mars. In addition to via melting of ice, perchlorate salts may also form liquid solutions by absorbing water vapor when the relative humidity is above a certain threshold in a process known as deliquescence. Formed either by melting or deliquescence, liquid solutions (brine) are the most likely way of liquid water activity on the Martian surface and in the shallow subsurface and are therefore important to understand the habitability of Mars. Using Raman spectroscopy, we provide reference spectra of various mixing states of liquid water, water ice and calcium perchlorate, all of which can occur during brine formation. We focus on the perchlorate symmetric stretching band and the O-H stretching vibrational band to distinguish brine from crystalline salt and water ice. We show that perchlorate brines can be identified by analyzing the peaks and their widths in the decomposed Raman spectra of the investigated samples. This serves as an important reference for future in-situ Raman spectrometers on Mars, such as those on the ExoMars and Mars 2020 rovers and can aid in the detection of brine formation on Mars. (Author)

Measurement of the human esophageal cancer in an early stage with Raman spectroscopy

Science.gov (United States)

Maeda, Yasuhiro; Ishigaki, Mika; Taketani, Akinori; Andriana, Bibin B.; Ishihara, Ryu; Sato, Hidetoshi

2014-02-01

The esophageal cancer has a tendency to transfer to another part of the body and the surgical operation itself sometimes gives high risk in vital function because many delicate organs exist near the esophagus. So the esophageal cancer is a disease with a high mortality. So, in order to lead a higher survival rate five years after the cancer's treatment, the investigation of the diagnosis methods or techniques of the cancer in an early stage and support the therapy are required. In this study, we performed the ex vivo experiments to obtain the Raman spectra from normal and early-stage tumor (stage-0) human esophageal sample by using Raman spectroscopy. The Raman spectra are collected by the homemade Raman spectrometer with the wavelength of 785 nm and Raman probe with 600-um-diameter. The principal component analysis (PCA) is performed after collection of spectra to recognize which materials changed in normal part and cancerous pert. After that, the linear discriminant analysis (LDA) is performed to predict the tissue type. The result of PCA indicates that the tumor tissue is associated with a decrease in tryptophan concentration. Furthermore, we can predict the tissue type with 80% accuracy by LDA which model is made by tryptophan bands.

In-SEM Raman microspectroscopy coupled with EDX - a case study of uranium reference particles

International Nuclear Information System (INIS)

Stefaniak, Elzbieta A.; Pointurier, Fabien; Marie, Olivier; Truyens, Jan; Aregbe, Yetunde

2014-01-01

Information about the molecular composition of airborne uranium-bearing particles may be useful as an additional tool for nuclear safeguards. In order to combine the detection of micrometer-sized particles with the analysis of their molecular forms, we used a hybrid system enabling Raman microanalysis in high vacuum inside a SEM chamber (SEM-SCA system). The first step involved an automatic scan of a sample to detect and save coordinates of uranium particles, along with X-ray microanalysis. In the second phase, the detected particles were relocated in a white light image and subjected to Raman microanalysis. The consecutive measurements by the two beams showed exceptional fragility of uranium particles, leading to their ultimate damage and change of uranium oxidation state. We used uranium reference particles prepared by hydrolysis of uranium hexafluoride to test the reliability of the Raman measurements inside the high vacuum. The results achieved by the hybrid system were verified by using a standalone Raman micro spectrometer. When deposited on exceptionally smooth substrates, uranyl fluoride particles smaller than 1000 nm could successfully be analyzed with the SEM-SCA system. (authors)

Non-destructive analysis of museum objects by fibre-optic Raman spectroscopy.

Science.gov (United States)

Vandenabeele, Peter; Tate, Jim; Moens, Luc

2007-02-01

Raman spectroscopy is a versatile technique that has frequently been applied for the investigation of art objects. By using mobile Raman instrumentation it is possible to investigate the artworks without the need for sampling. This work evaluates the use of a dedicated mobile spectrometer for the investigation of a range of museum objects in museums in Scotland, including antique Egyptian sarcophagi, a panel painting, painted surfaces on paper and textile, and the painted lid and soundboard of an early keyboard instrument. The investigations of these artefacts illustrate some analytical challenges that arise when analysing museum objects, including fluorescing varnish layers, ambient sunlight, large dimensions of artefacts and the need to handle fragile objects with care. Analysis of the musical instrument (the Mar virginals) was undertaken in the exhibition gallery, while on display, which meant that interaction with the public and health and safety issues had to be taken into account. Experimental set-up for the non-destructive Raman spectroscopic investigation of a textile banner in the National Museums of Scotland.

An Electrically Actuated Microbeam-Based MEMS Device: Experimental and Theoretical Investigation

KAUST Repository

Ruzziconi, Laura

2017-11-03

The present paper deals with the dynamic behavior of a microelectromechanical systems (MEMS). The device consists of a clamped-clamped microbeam electrostatically and electrodynamically actuated. Our objective is to develop a theoretical analysis, which is able to describe and predict all the main relevant aspects of the experimental response. In the first part of the paper an extensive experimental investigation is conducted. The microbeam is perfectly straight. The first three experimental natural frequencies are identified and the nonlinear dynamics are explored at increasing values of electrodynamic excitation. Several backward and forward frequency sweeps are acquired. The nonlinear behavior is highlighted. The experimental data show the coexistence of the nonresonant and the resonant branch, which perform a bending toward higher frequencies values before undergoing jump or pull-in dynamics. This kind of bending is not particularly common in MEMS. In the second part of the paper, a theoretical single degree-of-freedom model is derived. The unknown parameters are extracted and settled via parametric identification. A single mode reduced-order model is considered, which is obtained via the Galerkin technique. To enhance the computational efficiency, the contribution of the electric force term is computed in advance and stored in a table. Extensive numerical simulations are performed at increasing values of electrodynamic excitation. They are observed to properly predict all the main nonlinear features arising in the device response. This occurs not only at low values of electrodynamic excitation, but also at higher ones

Laser microbeams for the manipulation of plant cells and subcellular structures

International Nuclear Information System (INIS)

Hoffmann, F.

1996-01-01

Laser microsurgery has been used in plants to study physiological, cell biological and genetical questions for over 10 years. More recently, the optical trap became available as an additional tool. Specific areas of research include membrane physiology, motility, transformation and protoplast fusion. Compared to the data reported in animal systems, the contributions of laser microbeam manipulations in plant biology are rather limited. However, with increased awareness of the enormous potential of the technology and better accessibility to less expensive and more user-friendly equipment, the next decade should be more productive. (author)

UV-Photoreflectance and Raman Characterization of Strain Relaxation in Si on Silicon-Germanium Films

International Nuclear Information System (INIS)

Current, Michael; Chism, Will; Yoo, Woo Sik; Vartanian, Victor

2011-01-01

Photoreflectance (PR), using a uv (374 nm) diode laser probe beam, and Raman spectroscopy, using a multi-wavelength Ar + laser coupled to a high-resolution multi-wavelength spectrometer, were used to characterize the strain relaxation of Si top layers grown on a graded and relaxed SiGe buffer stack with a final Ge concentration of 20%. The Si top layer thicknesses ranged from 1.6 to 18 nm. Considerable radial variation in the strain relaxation was seen in all sampled wafers, highlighting the need for rapid, local strain characterization. Strong correlation between shift in the Si layer dielectric response, measured by uv-PR, and the Si top layer strain, measured by Raman, is reported.

Effects of locally targeted heavy-ion and laser microbeam on root hydrotropism in Arabidopsis thaliana

International Nuclear Information System (INIS)

Miyazawa, Yutaka; Sakashita, Tetsuya; Funayama, Tomoo

2008-01-01

Classical studies on root hydrotropism have hypothesized the importance of columella cells as well as the de novo gene expression, such as auxin-inducible gene, at the elongation zone in hydrotropism; however, there has been no confirmation that columella cells or auxin-mediated signaling in the elongation zone are necessary for hydrotropism. We examined the role of root cap and elongation zone cells in root hydrotropism using heavy-ion and laser microbeam. Heavy-ion microbeam irradiation of the elongation zone, but not that of the columella cells, significantly and temporarily suppressed the development of hydrotropic curvature. However, laser ablation confirmed that columella cells are indispensable for hydrotropism. Systemic heavy-ion broad-beam irradiation suppressed de novo expression of INDOLE ACETIC ACID 5 gene, but not MIZU-KUSSEI1 gene. Our results indicate that both the root cap and elongation zone have indispensable and functionally distinct roles in root hydrotropism, and that de novo gene expression might be required for hydrotropism in the elongation zone, but not in columella cells. (author)

Bystander-induced apoptosis and premature differentiation in primary urothelial explants after charged particle microbeam irradiation

International Nuclear Information System (INIS)

Belyakov, O.V.; Folkard, M.; Mothersill, C.; Prise, K.M.; Michael, B.D.

2002-01-01

The ureter primary explant technique was developed to study bystander effects under in vivo like conditions where stem and differentiated cells are present. Irradiation was performed with a 3 He 2+ charged particle microbeam available at the Gray Cancer Institute, with high (∼2 μm) precision. Tissue sections from porcine ureters were pre-irradiated with the microbeam at a single location with 10 3 He 2+ particles (5 MeV; LET 70 keV.μm -1 ). After irradiation, the tissue section was incubated for 7 days, thus allowing the explant outgrowth to form. Total cellular damage (total fraction of micronucleated and apoptotic cells) was measured according to morphological criteria. Apoptosis was also assessed using a 3'-OH DNA end-labelling technique. Premature differentiation was estimated using antibodies to uroplakin III, a specific marker of terminal urothelial differentiation. Results of our experiments demonstrated a significant bystander-induced differentiation and a less significant increase in apoptotic and micronucleated cells. A hypothesis based on the protective nature of the bystander effect is proposed. (author)

Studying nanostructure gradients in injection-molded polypropylene/montmorillonite composites by microbeam small-angle x-ray scattering

DEFF Research Database (Denmark)

Stribeck, Norbert; Schneider, Konrad; Zeinolebadi, Ahmad

2014-01-01

The core–shell structure in oriented cylindrical rods of polypropylene (PP) and nanoclay composites (NCs) from PP and montmorillonite (MMT) is studied by microbeam small-angle x-ray scattering (SAXS). The structure of neat PP is almost homogeneous across the rod showing regular semicrystalline......-shaped phyllosilicate filler particles....

Mechanical analysis of non-uniform bi-directional functionally graded intelligent micro-beams using modified couple stress theory

Science.gov (United States)

Bakhshi Khaniki, Hossein; Rajasekaran, Sundaramoorthy

2018-05-01

This study develops a comprehensive investigation on mechanical behavior of non-uniform bi-directional functionally graded beam sensors in the framework of modified couple stress theory. Material variation is modelled through both length and thickness directions using power-law, sigmoid and exponential functions. Moreover, beam is assumed with linear, exponential and parabolic cross-section variation through the length using power-law and sigmoid varying functions. Using these assumptions, a general model for microbeams is presented and formulated by employing Hamilton’s principle. Governing equations are solved using a mixed finite element method with Lagrangian interpolation technique, Gaussian quadrature method and Wilson’s Lagrangian multiplier method. It is shown that by using bi-directional functionally graded materials in nonuniform microbeams, mechanical behavior of such structures could be affected noticeably and scale parameter has a significant effect in changing the rigidity of nonuniform bi-directional functionally graded beams.

A Microbeam Small-Angle X-ray Scattering Study on Enamel Crystallites in Subsurface Lesion

Energy Technology Data Exchange (ETDEWEB)

Yagi, N; Ohta, N; Matsuo, T [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan); Tanaka, T; Terada, Y; Kamasaka, H; Kometani, T, E-mail: yagi@spring8.or.j [Ezaki Glico Co. Ltd., 4-6-5 Utajima, Nishiyodogawa-ku, Osaka 555-8502 (Japan)

2010-10-01

The early caries lesion in bovine tooth enamel was studied by two different X-ray diffraction systems at the SPring-8 third generation synchrotron radiation facility. Both allowed us simultaneous measurement of the small and large angle regions. The beam size was 6{mu}m at BL40XU and 50{mu}m at BL45XU. The small-angle scattering from voids in the hydroxyapatite crystallites and the wide-angle diffraction from the hydroxyapatite crystals were observed simultaneously. At BL40XU an X-ray image intensifier was used for the small-angle and a CMOS flatpanel detector for the large-angle region. At BL45XU, a large-area CCD detector was used to cover both regions. A linear microbeam scan at BL40XU showed a detailed distribution of voids and crystals and made it possible to examine the structural details in the lesion. The two-dimensional scan at BL45XU showed distribution of voids and crystals in a wider region in the enamel. The simultaneous small- and wide-angle measurement with a microbeam is a powerful tool to elucidate the mechanisms of demineralization and remineralization in the early caries lesion.

A Microbeam Small-Angle X-ray Scattering Study on Enamel Crystallites in Subsurface Lesion

International Nuclear Information System (INIS)

Yagi, N; Ohta, N; Matsuo, T; Tanaka, T; Terada, Y; Kamasaka, H; Kometani, T

2010-01-01

The early caries lesion in bovine tooth enamel was studied by two different X-ray diffraction systems at the SPring-8 third generation synchrotron radiation facility. Both allowed us simultaneous measurement of the small and large angle regions. The beam size was 6μm at BL40XU and 50μm at BL45XU. The small-angle scattering from voids in the hydroxyapatite crystallites and the wide-angle diffraction from the hydroxyapatite crystals were observed simultaneously. At BL40XU an X-ray image intensifier was used for the small-angle and a CMOS flatpanel detector for the large-angle region. At BL45XU, a large-area CCD detector was used to cover both regions. A linear microbeam scan at BL40XU showed a detailed distribution of voids and crystals and made it possible to examine the structural details in the lesion. The two-dimensional scan at BL45XU showed distribution of voids and crystals in a wider region in the enamel. The simultaneous small- and wide-angle measurement with a microbeam is a powerful tool to elucidate the mechanisms of demineralization and remineralization in the early caries lesion.

In situ macromolecular crystallography using microbeams

International Nuclear Information System (INIS)

Axford, Danny; Owen, Robin L.; Aishima, Jun; Foadi, James; Morgan, Ann W.; Robinson, James I.; Nettleship, Joanne E.; Owens, Raymond J.; Moraes, Isabel; Fry, Elizabeth E.; Grimes, Jonathan M.; Harlos, Karl; Kotecha, Abhay; Ren, Jingshan; Sutton, Geoff; Walter, Thomas S.; Stuart, David I.; Evans, Gwyndaf

2012-01-01

A sample environment for mounting crystallization trays has been developed on the microfocus beamline I24 at Diamond Light Source. The technical developments and several case studies are described. Despite significant progress in high-throughput methods in macromolecular crystallography, the production of diffraction-quality crystals remains a major bottleneck. By recording diffraction in situ from crystals in their crystallization plates at room temperature, a number of problems associated with crystal handling and cryoprotection can be side-stepped. Using a dedicated goniometer installed on the microfocus macromolecular crystallography beamline I24 at Diamond Light Source, crystals have been studied in situ with an intense and flexible microfocus beam, allowing weakly diffracting samples to be assessed without a manual crystal-handling step but with good signal to noise, despite the background scatter from the plate. A number of case studies are reported: the structure solution of bovine enterovirus 2, crystallization screening of membrane proteins and complexes, and structure solution from crystallization hits produced via a high-throughput pipeline. These demonstrate the potential for in situ data collection and structure solution with microbeams

Negative Knudsen force on heated microbeams

KAUST Repository

Zhu, Taishan

2011-11-18

Knudsen force acting on a heated microbeam adjacent to a cold substrate in a rarefied gas is a mechanical force created by unbalanced thermal gradients. The measured force has its direction pointing towards the side with a lower thermal gradient and its magnitude vanishes in both continuum and free-molecule limits. In our previous study, negative Knudsen forces were discovered at the high Knudsen regime before diminishing in the free-molecule limit. Such a phenomenon was, however, neither observed in experiment [A. Passian et al., Phys. Rev. Lett. 90, 124503 (2003)], nor captured in the latest numerical study [J. Nabeth et al., Phys. Rev. E 83, 066306 (2011)]. In this paper, the existence of such a negative Knudsen force is further confirmed using both numerical simulation and theoretical analysis. The asymptotic order of the Knudsen force near the collisionless limit is analyzed and the analytical expression of its leading term is provided, from which approaches for the enhancement of negative Knudsen forces are proposed. The discovered phenomenon could find its applications in novel mechanisms for pressure sensing and actuation.

In situ macromolecular crystallography using microbeams

Energy Technology Data Exchange (ETDEWEB)

Axford, Danny; Owen, Robin L.; Aishima, Jun [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Foadi, James [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Imperial College, London SW7 2AZ (United Kingdom); Morgan, Ann W.; Robinson, James I. [University of Leeds, Leeds LS9 7FT (United Kingdom); Nettleship, Joanne E.; Owens, Raymond J. [Research Complex at Harwell, Rutherford Appleton Laboratory R92, Didcot, Oxfordshire OX11 0DE (United Kingdom); Moraes, Isabel [Imperial College, London SW7 2AZ (United Kingdom); Fry, Elizabeth E.; Grimes, Jonathan M.; Harlos, Karl; Kotecha, Abhay; Ren, Jingshan; Sutton, Geoff; Walter, Thomas S. [University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Stuart, David I. [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Evans, Gwyndaf, E-mail: gwyndaf.evans@diamond.ac.uk [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom)

2012-04-17

A sample environment for mounting crystallization trays has been developed on the microfocus beamline I24 at Diamond Light Source. The technical developments and several case studies are described. Despite significant progress in high-throughput methods in macromolecular crystallography, the production of diffraction-quality crystals remains a major bottleneck. By recording diffraction in situ from crystals in their crystallization plates at room temperature, a number of problems associated with crystal handling and cryoprotection can be side-stepped. Using a dedicated goniometer installed on the microfocus macromolecular crystallography beamline I24 at Diamond Light Source, crystals have been studied in situ with an intense and flexible microfocus beam, allowing weakly diffracting samples to be assessed without a manual crystal-handling step but with good signal to noise, despite the background scatter from the plate. A number of case studies are reported: the structure solution of bovine enterovirus 2, crystallization screening of membrane proteins and complexes, and structure solution from crystallization hits produced via a high-throughput pipeline. These demonstrate the potential for in situ data collection and structure solution with microbeams.

Characterization of arsenic-contaminated aquifer sediments from eastern Croatia by ion microbeam, PIXE and ICP-OES techniques

Energy Technology Data Exchange (ETDEWEB)

Ujević Bošnjak, M., E-mail: magdalena.ujevic@hzjz.hr [Croatian National Institute of Public Health, Rockefelerova 7, 10000 Zagreb (Croatia); Fazinić, S. [Institute Ruđer Bošković, Bijenička cesta, 10000 Zagreb (Croatia); Duić, Ž. [University of Zagreb, Faculty of Mining, Geology and Petroleum Engineering, Pierottijeva 6, Zagreb (Croatia)

2013-10-01

Highlights: •ICP-OES and PIXE used in the characterization of As-contaminated sediments. •Observed high correlations between the results obtained by those techniques. •Discrepancies observed for Mn, and for the highest As concentrations. •Microbeam analyses showed As association with sulphides and iron. -- Abstract: Groundwater arsenic contamination has been evidenced in eastern Croatia and hydrochemical results suggest that the occurrence of arsenic in the groundwater depends on the local geology, hydrogeology, and geochemical characteristics of the aquifer. In order to perform the sediment characterization and to investigate arsenic association with the other elements in the sediments, 10 samples from two boreholes (PVc-3 and Gundinci 1) in eastern Croatia were analyzed using two techniques: PIXE (without sample pre-treatment) and ICP-OES (after digestion), as well by ion microbeam analyses. The results of the PIXE and ICP-OES techniques showed quite good agreement; however, greater discrepancies were observed at the higher arsenic and manganese mass ratios. According to both techniques, higher As mass ratios were observed in the sediments from the PVc-3 core (up to 651 mg/kg and 491 mg/kg using PIXE and ICP-OES analyses respectively) than from the Gundinci 1 core (up to 60 mg/kg using both techniques). Although arsenic association with Fe is expected, no correlation was observed. The microbeam analyses demonstrated that arsenic is associated with sulphides and iron in the most As-contaminated sample from the PVc-3 core, while this relationship was not evident in the most As-contaminated sample from the Gundinci 1 borehole.

Characterization of arsenic-contaminated aquifer sediments from eastern Croatia by ion microbeam, PIXE and ICP-OES techniques

International Nuclear Information System (INIS)

Ujević Bošnjak, M.; Fazinić, S.; Duić, Ž.

2013-01-01

Highlights: •ICP-OES and PIXE used in the characterization of As-contaminated sediments. •Observed high correlations between the results obtained by those techniques. •Discrepancies observed for Mn, and for the highest As concentrations. •Microbeam analyses showed As association with sulphides and iron. -- Abstract: Groundwater arsenic contamination has been evidenced in eastern Croatia and hydrochemical results suggest that the occurrence of arsenic in the groundwater depends on the local geology, hydrogeology, and geochemical characteristics of the aquifer. In order to perform the sediment characterization and to investigate arsenic association with the other elements in the sediments, 10 samples from two boreholes (PVc-3 and Gundinci 1) in eastern Croatia were analyzed using two techniques: PIXE (without sample pre-treatment) and ICP-OES (after digestion), as well by ion microbeam analyses. The results of the PIXE and ICP-OES techniques showed quite good agreement; however, greater discrepancies were observed at the higher arsenic and manganese mass ratios. According to both techniques, higher As mass ratios were observed in the sediments from the PVc-3 core (up to 651 mg/kg and 491 mg/kg using PIXE and ICP-OES analyses respectively) than from the Gundinci 1 core (up to 60 mg/kg using both techniques). Although arsenic association with Fe is expected, no correlation was observed. The microbeam analyses demonstrated that arsenic is associated with sulphides and iron in the most As-contaminated sample from the PVc-3 core, while this relationship was not evident in the most As-contaminated sample from the Gundinci 1 borehole

The reliability of Raman micro-spectroscopy in measuring the density of CO2 mantle fluids

Science.gov (United States)

Remigi, S.; Frezzotti, M. L.; Ferrando, S.; Villa, I. M.; Maffeis, A.

2017-12-01

Recent evaluations of carbon fluxes into and out the Earth's interior recognize that a significant part of the total outgassing of deep Earth carbon occurs in tectonically active areas (Kelemen and Manning, 2015). Potential tracers of carbon fluxes at mantle depths include CO2 fluid inclusions in peridotites. Raman micro-spectroscopy allows calculating the density of CO2 fluids based on the distance of the CO2 Fermi doublet, Δ, in cm-1 (Rosso and Bodnar, 1995). The aim of this work is to check the reliability of Raman densimeter equations (cf. Lamadrid et al., 2016) for high-density CO2 fluids originating at mantle depths. Forty pure CO2 inclusions in peridotites (El Hierro, Canary Islands) of known density (microthermometry) have been analyzed by Raman micro-spectroscopy. In order to evaluate the influence of contaminants on the reliability of equations, 22 CO2-rich inclusions containing subordinate amounts of N2, CO, SO2 have also been studied. Raman spectrometer analytical conditions are: 532 nm laser, 80 mW emission power, T 18°C, 1800 and 600 grating, 1 accumulation x 80 sec. Daily calibration included diamond and atmosphere N2. Results suggest that the "Raman densimeter" represents an accurate method to calculate the density of CO2 mantle fluids. Equations, however, must be applied only to pure CO2 fluids, since contaminants, even in trace amounts (0.39 mol%), affect the Δ resulting in density overestimation. Present study further highlights how analytical conditions and data processing, such as spectral resolution (i.e., grating), calibration linearity, and statistical treatment of spectra, influence the accuracy and the precision of Δ measurements. As a consequence, specific analytical protocols for single Raman spectrometers should be set up in order to get reliable CO2 density data. Kelemen, Peter B., & Craig E. Manning. PNAS, 112.30 (2015): E3997-E4006.Lamadrid, H. M., Moore, L. R., Moncada, D., Rimstidt, J. D., Burruss, R. C., & Bodnar, R. J. Chem

Raman acoustic levitation spectroscopy of red blood cells and Plasmodium falciparum trophozoites.

Science.gov (United States)

Puskar, Ljiljana; Tuckermann, Rudolf; Frosch, Torsten; Popp, Jürgen; Ly, Vanalysa; McNaughton, Don; Wood, Bayden R

2007-09-01

Methods to probe the molecular structure of living cells are of paramount importance in understanding drug interactions and environmental influences in these complex dynamical systems. The coupling of an acoustic levitation device with a micro-Raman spectrometer provides a direct molecular probe of cellular chemistry in a containerless environment minimizing signal attenuation and eliminating the affects of adhesion to walls and interfaces. We show that the Raman acoustic levitation spectroscopic (RALS) approach can be used to monitor the heme dynamics of a levitated 5 microL suspension of red blood cells and to detect hemozoin in malaria infected cells. The spectra obtained have an excellent signal-to-noise ratio and demonstrate for the first time the utility of the technique as a diagnostic and monitoring tool for minute sample volumes of living animal cells.

Stand-off detection of chemicals by UV Raman spectroscopy

International Nuclear Information System (INIS)

Wu, Ming; Ray, Mark; Hang Fung, K.; Ruckman, Mark W.; Harder, David; Sedlacek, Arthur J. III

2000-01-01

Experimental results are reported on a mobile, stand-alone, solar-blind ultraviolet (UV) Raman lidar system for the stand-off detection and identification of liquid and solid targets at ranges of hundreds of meters. The lidar is a coaxial system capable of performing range-resolved measurements of gases and aerosols, as well as solids and liquids. The transmitter is a flash lamp pumped 30 Hz Nd:YAG laser with quadrupled output at 266 nm. The receiver subsystem is comprised of a 40 cm Cassegrain telescope, a holographic UV edge filter for suppressing the elastic channel, a 0.46 m Czerny-Turner spectrometer, and a time gated intensified charge-coupled device (CCD) detector. The rejection of elastic light scattering by the edge filter is better than one part in 10 5 , while the transmittance 500 cm-1 to the red of the laser line is greater than 50%. Raman data are shown for selected solids, neat liquids, and mixtures down to the level of 1% volume ratio. On the basis of the strength of the Raman returns, a stand-off detection limit of ∼500 g/m2 for liquid spills of common solvents at the range of one half of a kilometer is possible. (c) 2000 Society for Applied Spectroscopy

Analysis of strain error sources in micro-beam Laue diffraction

International Nuclear Information System (INIS)

Hofmann, Felix; Eve, Sophie; Belnoue, Jonathan; Micha, Jean-Sébastien; Korsunsky, Alexander M.

2011-01-01

Micro-beam Laue diffraction is an experimental method that allows the measurement of local lattice orientation and elastic strain within individual grains of engineering alloys, ceramics, and other polycrystalline materials. Unlike other analytical techniques, e.g. based on electron microscopy, it is not limited to surface characterisation or thin sections, but rather allows non-destructive measurements in the material bulk. This is of particular importance for in situ loading experiments where the mechanical response of a material volume (rather than just surface) is studied and it is vital that no perturbation/disturbance is introduced by the measurement technique. Whilst the technique allows lattice orientation to be determined to a high level of precision, accurate measurement of elastic strains and estimating the errors involved is a significant challenge. We propose a simulation-based approach to assess the elastic strain errors that arise from geometrical perturbations of the experimental setup. Using an empirical combination rule, the contributions of different geometrical uncertainties to the overall experimental strain error are estimated. This approach was applied to the micro-beam Laue diffraction setup at beamline BM32 at the European Synchrotron Radiation Facility (ESRF). Using a highly perfect germanium single crystal, the mechanical stability of the instrument was determined and hence the expected strain errors predicted. Comparison with the actual strain errors found in a silicon four-point beam bending test showed good agreement. The simulation-based error analysis approach makes it possible to understand the origins of the experimental strain errors and thus allows a directed improvement of the experimental geometry to maximise the benefit in terms of strain accuracy.

Discrimination of Pigments of Microalgae, Bacteria and Yeasts Using Lightweight Handheld Raman Spectrometers: Prospects for Astrobiology

Science.gov (United States)

Jehlicka, J.; Osterrothova, K.; Nedbalova, L.; Gunde-Cimerman, N.; Oren, A.

2014-06-01

Handheld Raman instrumentation with 532 nm lasers can be used to distinguish carotenoids of autotrophic microalgae, purple sulfur bacteria, halophilic Archaea and pigmented yeasts. Pigments are proposed as biomarkers for astrobiology of Mars.

PREFACE: EMAS 2011: 12th European Workshop on Modern Developments in Microbeam Analysis

Science.gov (United States)

Brisset, François; Dugne, Olivier; Robaut, Florence; Lábár, János L.; Walker, Clive T.

2012-03-01

This volume of IOP Conference Series: Materials Science and Engineering contains papers from the 12th Workshop of the European Microbeam Analysis Society (EMAS) on Modern Developments and Applications in Microbeam Analysis, which took place from the 15-19 May 2011 in the Angers Congress Centre, Angers, France. The primary aim of this series of workshops is to assess the state-of-the-art and reliability of microbeam analysis techniques. The workshops also provide a forum where students and young scientists starting out on a career in microbeam analysis can meet and discuss with the established experts. The workshops have a very specific format comprising invited plenary lectures by internationally recognized experts, poster presentations by the participants and round table discussions on the key topics led by specialists in the field. This workshop was organized in collaboration with GN-MEBA - Groupement National de Microscopie Electronique à Balayage et de microAnalysis, France. The technical programme included the following topics: the limits of EPMA, new techniques, developments and concepts in microanalysis, microanalysis in the SEM, and new and less common applications of micro- and nanoanalysis. As at previous workshops there was also a special oral session for young scientists. The best presentation by a young scientist was awarded with an invitation to attend the 2012 Microscopy and Microanalysis meeting at Phoenix, Arizona. The prize went to Pierre Burdet, of the Federal Institute of Technology of Lausanne (EPFL), for his talk entitled '3D EDS microanalysis by FIB-SEM: enhancement of elemental quantification'. The continuing relevance of the EMAS workshops and the high regard in which they are held internationally can be seen from the fact that 74 posters from 18 countries were on display at the meeting, and that the participants came from as far away as Japan, Canada and the USA. A selection of participants with posters were invited to give a short oral

Test report for remote vs. contact Raman spectroscopy

International Nuclear Information System (INIS)

Kyle, K.R.

1994-05-01

This report details the evaluation of two methods of spatially characterizing the chemical composition of tank core samples using Raman spectroscopy. One method involves a spatially-scanned fiber optic probe. The fiber optic probe must be in contact with a sample to interrogate its chemical composition. The second method utilizes a line-of-sight technique involving a remote imaging spectrometer that can perform characterization over an entire surface. Measurements using the imaging technique are done remotely, requiring no contact with the sample surface. The scope of this document studies the effects of laser power, distance from each type of probe to the sample surface, and interferences unique to the two methods. This report also documents the results of comparative studies of sensitivity to ferrocyanide, a key contaminant of concern in the underground storage tanks at DOE's Hanford site. The effect of other factors on signal intensity such as moisture content is explored. The results from the two methods are compared, and a recommendation for a Raman hot cell core scanning system is presented based on the test results. This work is part of a joint effort involving several DOE laboratories for the design and development of Raman spectroscopy systems for tank waste characterization at Westinghouse Hanford Company under the auspices of the U.S. Department of Energy's Underground Storage Tank Integrated Demonstration

Electrothermally actuated tunable clamped-guided resonant microbeams

Science.gov (United States)

Alcheikh, N.; Hajjaj, A. Z.; Jaber, N.; Younis, M. I.

2018-01-01

We present simulation and experimental investigation demonstrating active alteration of the resonant and frequency response behavior of resonators by controlling the electrothermal actuation method on their anchors. In-plane clamped-guided arch and straight microbeams resonators are designed and fabricated with V-shaped electrothermal actuators on their anchors. These anchors not only offer various electrothermal actuation options, but also serve as various mechanical stiffness elements that affect the operating resonance frequency of the structures. We have shown that for an arch, the first mode resonance frequency can be increased up to 50% of its initial value. For a straight beam, we have shown that before buckling, the resonance frequency decreases to very low values and after buckling, it increases up to twice of its initial value. These results can be promising for the realization of different wide-range tunable microresonator. The experimental results have been compared to multi-physics finite-element simulations showing good agreement among them.

Electrothermally actuated tunable clamped-guided resonant microbeams

KAUST Repository

Alcheikh, Nouha

2017-06-11

We present simulation and experimental investigation demonstrating active alteration of the resonant and frequency response behavior of resonators by controlling the electrothermal actuation method on their anchors. In-plane clamped-guided arch and straight microbeams resonators are designed and fabricated with V-shaped electrothermal actuators on their anchors. These anchors not only offer various electrothermal actuation options, but also serve as various mechanical stiffness elements that affect the operating resonance frequency of the structures. We have shown that for an arch, the first mode resonance frequency can be increased up to 50% of its initial value. For a straight beam, we have shown that before buckling, the resonance frequency decreases to very low values and after buckling, it increases up to twice of its initial value. These results can be promising for the realization of different wide–range tunable microresonator. The experimental results have been compared to multi-physics finite-element simulations showing good agreement among them.

Radiosurgery using heavy ion microbeams for biological study: Fate mapping of the cellular blastoderm-stage egg of the silkworm, Bombyx mori

International Nuclear Information System (INIS)

Kiguchi, Kenji; Shirai, Koji; Kanekatsu, Rensuke; Kobayashi, Yasuhiko; Tu, Z.-L.; Funayama, Tomoo; Watanabe, Hiroshi

2003-01-01

We investigated the effects of heavy ions on embryogenesis of the silkworm, Bombyx mori using a collimated heavy ion microbeam from the vertical beam line of an AVF-cyclotron. Eggs were exposed to carbon ions at the cellular blastoderm stage. Microbeams were found to be extremely useful for radio-microsurgical inactivation of nuclei or cells in the target site. Spot irradiation caused abnormal embryos, which showed localized defects such as deletion, duplication and fusion, depending on dose, beam size and site of irradiation. The location and frequency of defects on the resultant embryos were closely correlated to the irradiation site. Based on this correlation, a fate map was established for the Bombyx egg at the cellular blastoderm stage

Radiosurgery using heavy ion microbeams for biological study: Fate mapping of the cellular blastoderm-stage egg of the silkworm, Bombyx mori

Energy Technology Data Exchange (ETDEWEB)

Kiguchi, Kenji E-mail: kkiguch@giptc.shinshu-u.ac.jp; Shirai, Koji; Kanekatsu, Rensuke; Kobayashi, Yasuhiko; Tu, Z.-L.; Funayama, Tomoo; Watanabe, Hiroshi

2003-09-01

We investigated the effects of heavy ions on embryogenesis of the silkworm, Bombyx mori using a collimated heavy ion microbeam from the vertical beam line of an AVF-cyclotron. Eggs were exposed to carbon ions at the cellular blastoderm stage. Microbeams were found to be extremely useful for radio-microsurgical inactivation of nuclei or cells in the target site. Spot irradiation caused abnormal embryos, which showed localized defects such as deletion, duplication and fusion, depending on dose, beam size and site of irradiation. The location and frequency of defects on the resultant embryos were closely correlated to the irradiation site. Based on this correlation, a fate map was established for the Bombyx egg at the cellular blastoderm stage.

Dual-resolution Raman spectroscopy for measurements of temperature and twelve species in hydrocarbon–air flames

Energy Technology Data Exchange (ETDEWEB)

Magnotti, Gaetano; Barlow, Robert S.

2016-07-12

This study introduces dual-resolution Raman spectroscopy as a novel diagnostics approach for measurements of temperature and species in flames where multiple hydrocarbons are present. Simultaneous measurement of multiple hydrocarbons is challenging because their vibrational Raman spectra in the C–H stretch region are closely overlapped and are not well known over the range of temperature encountered in flames. Overlap between the hydrocarbon spectra is mitigated by adding a second spectrometer, with a higher dispersion grating, to collect the Raman spectra in the C–H stretch region. A dual-resolution Raman spectroscopy instrument has been developed and optimized for measurements of major species (N₂, O₂, H₂O, CO₂, CO, H₂, DME) and major combustion intermediates (CH₄, CH₂O, C₂H₂, C₂H₄ and C₂H₆) in DME–air flames. The temperature dependences of the hydrocarbon Raman spectra over fixed spectral regions have been determined through a series of measurements in laminar Bunsen-burner flames, and have been used to extend a library of previously acquired Raman spectra up to flame temperature. The paper presents the first Raman measurements of up to twelve species in hydrocarbon flames, and the first quantitative Raman measurements of formaldehyde in flames. Lastly, the accuracy and precision of the instrument are determined from measurements in laminar flames and the applicability of the instrument to turbulent DME–air flames is discussed.

Scanning three-dimensional x-ray diffraction microscopy using a high-energy microbeam

International Nuclear Information System (INIS)

Hayashi, Y.; Hirose, Y.; Seno, Y.

2016-01-01

A scanning three-dimensional X-ray diffraction (3DXRD) microscope apparatus with a high-energy microbeam was installed at the BL33XU Toyota beamline at SPring-8. The size of the 50 keV beam focused using Kirkpatrick-Baez mirrors was 1.3 μm wide and 1.6 μm high in full width at half maximum. The scanning 3DXRD method was tested for a cold-rolled carbon steel sheet sample. A three-dimensional orientation map with 37 "3 voxels was obtained.

Scanning three-dimensional x-ray diffraction microscopy using a high-energy microbeam

Energy Technology Data Exchange (ETDEWEB)

Hayashi, Y., E-mail: y-hayashi@mosk.tytlabs.co.jp; Hirose, Y.; Seno, Y. [Toyota Central R& D Toyota Central R& D Labs., Inc., 41-1 Nagakute Aichi 480-1192 Japan (Japan)

2016-07-27

A scanning three-dimensional X-ray diffraction (3DXRD) microscope apparatus with a high-energy microbeam was installed at the BL33XU Toyota beamline at SPring-8. The size of the 50 keV beam focused using Kirkpatrick-Baez mirrors was 1.3 μm wide and 1.6 μm high in full width at half maximum. The scanning 3DXRD method was tested for a cold-rolled carbon steel sheet sample. A three-dimensional orientation map with 37 {sup 3} voxels was obtained.

Stimulated Raman spectroscopy and nanoscopy of molecules using near field photon induced forces without resonant electronic enhancement gain

Energy Technology Data Exchange (ETDEWEB)

Tamma, Venkata Ananth [CaSTL Center, Department of Chemistry, University of California, Irvine, California 92697 (United States); Huang, Fei; Kumar Wickramasinghe, H., E-mail: hkwick@uci.edu [Department of Electrical Engineering and Computer Science, 142 Engineering Tower, University of California, Irvine, California 92697 (United States); Nowak, Derek [Molecular Vista, Inc., 6840 Via Del Oro, San Jose, California 95119 (United States)

2016-06-06

We report on stimulated Raman spectroscopy and nanoscopy of molecules, excited without resonant electronic enhancement gain, and recorded using near field photon induced forces. Photon-induced interaction forces between the sharp metal coated silicon tip of an Atomic Force Microscope (AFM) and a sample resulting from stimulated Raman excitation were detected. We controlled the tip to sample spacing using the higher order flexural eigenmodes of the AFM cantilever, enabling the tip to come very close to the sample. As a result, the detection sensitivity was increased compared with previous work on Raman force microscopy. Raman vibrational spectra of azobenzene thiol and l-phenylalanine were measured and found to agree well with published results. Near-field force detection eliminates the need for far-field optical spectrometer detection. Recorded images show spatial resolution far below the optical diffraction limit. Further optimization and use of ultrafast pulsed lasers could push the detection sensitivity towards the single molecule limit.

Handheld Raman Spectroscopy for the Distinction of Essential Oils Used in the Cosmetics Industry

Directory of Open Access Journals (Sweden)

Paul Vargas Jentzsch

2015-05-01

Full Text Available Essential oils are highly appreciated by the cosmetics industry because they have antimicrobial and antioxidant properties, among others. Since essential oils are natural products, their inclusion in cosmetic formulations is a common practice. Currently, low-quality and/or adulterated essential oils can be found on the market; therefore, analytical methods for control are required. Raman spectroscopy is a versatile technique that can be used for quality control tasks; the portability of modern devices expand the analytical possibilities also to in situ measurements. Fifteen essential oils of interest for the cosmetics industry were measured using a handheld Raman spectrometer, and the assignment of the main bands observed in their average spectra was proposed. In most cases, it is possible to distinguish the essential oils by a simple visual inspection of their characteristic Raman bands. However, for essential oils extracted from closely-related vegetable species and containing the same main component in a very high proportion, the visual inspection of the spectra may be not enough, and the application of chemometric methods is suggested. Characteristic Raman bands for each essential oil can be used to both identify the essential oils and detect adulterations.

Rapid detection of benzoyl peroxide in wheat flour by using Raman scattering spectroscopy

Science.gov (United States)

Zhao, Juan; Peng, Yankun; Chao, Kuanglin; Qin, Jianwei; Dhakal, Sagar; Xu, Tianfeng

2015-05-01

Benzoyl peroxide is a common flour additive that improves the whiteness of flour and the storage properties of flour products. However, benzoyl peroxide adversely affects the nutritional content of flour, and excess consumption causes nausea, dizziness, other poisoning, and serious liver damage. This study was focus on detection of the benzoyl peroxide added in wheat flour. A Raman scattering spectroscopy system was used to acquire spectral signal from sample data and identify benzoyl peroxide based on Raman spectral peak position. The optical devices consisted of Raman spectrometer and CCD camera, 785 nm laser module, optical fiber, prober, and a translation stage to develop a real-time, nondestructive detection system. Pure flour, pure benzoyl peroxide and different concentrations of benzoyl peroxide mixed with flour were prepared as three sets samples to measure the Raman spectrum. These samples were placed in the same type of petri dish to maintain a fixed distance between the Raman CCD and petri dish during spectral collection. The mixed samples were worked by pretreatment of homogenization and collected multiple sets of data of each mixture. The exposure time of this experiment was set at 0.5s. The Savitzky Golay (S-G) algorithm and polynomial curve-fitting method was applied to remove the fluorescence background from the Raman spectrum. The Raman spectral peaks at 619 cm-1, 848 cm-1, 890 cm-1, 1001 cm-1, 1234 cm-1, 1603cm-1, 1777cm-1 were identified as the Raman fingerprint of benzoyl peroxide. Based on the relationship between the Raman intensity of the most prominent peak at around 1001 cm-1 and log values of benzoyl peroxide concentrations, the chemical concentration prediction model was developed. This research demonstrated that Raman detection system could effectively and rapidly identify benzoyl peroxide adulteration in wheat flour. The experimental result is promising and the system with further modification can be applicable for more products in near

Scanning ion micro-beam techniques for measuring diffusion in heterogeneous materials

International Nuclear Information System (INIS)

Jenneson, P.M.; Clough, A.S.

1998-01-01

A raster scanning MeV micro-beam of 1 H + or 3 He + ions was used to study the diffusion of small molecules in heterogeneous materials. The location of elemental contaminants (heavier than Lithium) in polymer insulated cables was studied with 1 H micro-Particle Induced X-ray Emission (μPIXE). Concentration profiles of a deuterated molecule in a hair fibre were determined with 3 He micro-Nuclear Reaction Analysis (μNRA). Chlorine and heavy water (D 2 0) diffusion into cement pastes were profiled using a combination of 3 He μPIXE and μNRA. (authors)

X-ray microbeam stand-alone facility for cultured cells irradiation

Energy Technology Data Exchange (ETDEWEB)

Bożek, Sebastian, E-mail: sebastian.bozek@yahoo.com [Jagiellonian University Medical College, Department of Pharmaceutical Biophysics, Krakow (Poland); Bielecki, Jakub; Wiecheć, Anna; Lekki, Janusz; Stachura, Zbigniew; Pogoda, Katarzyna; Lipiec, Ewelina; Tkocz, Konrad; Kwiatek, Wojciech M. [Institute of Nuclear Physics Polish Academy of Sciences, PL-31342 Krakow (Poland)

2017-03-01

Highlights: • An X-ray microbeam line for irradiation of living cultured cells was constructed. • A step by step explanation of working principles with engineering details, procedures and calculations is presented. • A model of beam and cell interaction is presented. • A method of uniform irradiation of living cells with an exact dose per a cell is presented. • Results of preliminary experiments are presented. - Abstract: The article describes an X-ray microbeam standalone facility dedicated for irradiation of living cultured cells. The article can serve as an advice for such facilities construction, as it begins from engineering details, through mathematical modeling and experimental procedures, ending up with preliminary experimental results and conclusions. The presented system consists of an open type X-ray tube with microfocusing down to about 2 μm, an X-ray focusing system with optical elements arranged in the nested Kirckpatrick-Baez (or Montel) geometry, a sample stand and an optical microscope with a scientific digital CCD camera. For the beam visualisation an X-ray sensitive CCD camera and a spectral detector are used, as well as a scintillator screen combined with the microscope. A method of precise one by one irradiation of previously chosen cells is presented, as well as a fast method of uniform irradiation of a chosen sample area. Mathematical models of beam and cell with calculations of kerma and dose are presented. The experiments on dose-effect relationship, kinetics of DNA double strand breaks repair, as well as micronuclei observation were performed on PC-3 (Prostate Cancer) cultured cells. The cells were seeded and irradiated on Mylar foil, which covered a hole drilled in the Petri dish. DNA lesions were visualised with γ-H2AX marker combined with Alexa Fluor 488 fluorescent dye.

Stable isotope ratio measurements in hydrogen, nitrogen, and oxygen using Raman scattering

International Nuclear Information System (INIS)

Harney, R.C.; Bloom, S.D.; Milanovich, F.P.

1975-01-01

A method for measuring stable isotope ratios using laser Raman scattering was developed which may prove of significant utility and benefit in stable isotope tracer studies. Crude isotope ratio measurements obtained with a low-power laser indicate that with current technology it should be possible to construct an isotope ratio measurement system using laser Raman scattering that is capable of performing 0.1 percent accuracy isotope ratio measurements of 16 O/ 18 O in natural abundance oxygen gas or 14 N/ 15 N in natural abundance nitrogen gas in times less than two minutes per sample. Theory pertinent to the technique, designs of specific isotope ratio spectrometer systems, and data relating to isotope ratio measurements in hydrogen, nitrogen, and oxygen are presented. In addition, the current status of several studies utilizing this technique is discussed. (auth)

Raman signal enhancement by multiple beam excitation and its application for the detection of chemicals

Energy Technology Data Exchange (ETDEWEB)

Gupta, Sakshi [Laser Science and Technology Centre, Metcalfe House, Delhi 110054 (India); Instrument Design and Development Centre, Indian Institute of Technology, Hauz Khas, New Delhi 110016 (India); Ahmad, Azeem; Mehta, Dalip S., E-mail: mehtads@physics.iitd.ac.in [Department of Physics, Indian Institute of Technology, Hauz Khas, New Delhi 110016 (India); Gambhir, Vijayeta; Reddy, Martha N. [Laser Science and Technology Centre, Metcalfe House, Delhi 110054 (India)

2015-08-31

In a typical Raman based sensor, a single laser beam is used for exciting the sample and the backscattered or forward scattered light is collected using collection optics and is analyzed by a spectrometer. We have investigated that by means of exciting the sample with multiple beams, i.e., by dividing the same input power of the single beam into two or three or more beams and exciting the sample from different angles, the Raman signal enhances significantly. Due to the presence of multiple beams passing through the same volume of the sample, an interference pattern is formed and the volume of interaction of excitation beams with the sample increases. By means of this geometry, the enhancement in the Raman signal is observed and it was found that the signal strength increases linearly with the increase in number of excitation beams. Experimental results of this scheme for excitation of the samples are reported for explosive detection at a standoff distance.

Earth, soil and environmental science research facility at sector 13 of the Advanced Photon Source. II. Scientific program and experimental instrumentation

Energy Technology Data Exchange (ETDEWEB)

Sutton, S.; Eng., P.J.; Jaski, Y.R.; Lazaraz, N.; Pluth, J.; Murray, P.; Rarback, H.; Rivers, M. [CARS, 5640 S. Ellis Avenue, University of Chicago, Chicago, IL (United States)

1996-09-01

The GSECARS (APS sector 13) scientific program will provide fundamental new information on the deep structure and composition of the Earth and other planets, the formation of economic mineral deposits, the cycles and fate of toxic metals in the environment, and the mechanisms of nutrient uptake and disease in plants. In the four experimental stations (2 per beamline), scientists will have access to three main x-ray techniques: diffraction (microcrystal, powder, diamond anvil cell, and large volume press), fluorescence microprobe, and spectroscopy (conventional, microbeam, liquid and solid surfaces). The high pressure facilities will be capable of x-ray crystallography at P{approx_gt}360 GPa and T{approximately}6000 K with the diamond anvil cell and P{approximately}25 GPa and T{approximately}2500{degree}C with the large volume press. Diffractometers will allow study of 1 micrometer crystals and micro-powders. The microprobe (1 micrometer focused beam) will be capable of chemical analyses in the sub-ppm range using wavelength and energy dispersive detectors. Spectroscopy instrumentation will be available for XANES and EXAFS with microbeams as well as high sensitivity conventional XAS and studies of liquid and solid interfaces. Visiting scientists will be able to setup, calibrate, and test experiments in off-line laboratories with equipment such as micromanipulators, optical microscopes, clean bench, glove boxes, high powered optical and Raman spectrometers. {copyright} {ital 1996 American Institute of Physics.}

Macro and micro Raman spectroscopy of YBa2Cu3O7 films and microbridges

International Nuclear Information System (INIS)

Bock, A.

1993-01-01

In the present work Raman spectroscopy is used as a method to characterize the properties of YBa 2 Cu 3 O 7 -films. This is done in the usual (macro-)Raman set-up as well as in the micro-Raman set-up where the spatial resolution is about one micron. To obtain comparable results the Raman spectra have to be corrected for the spectral response of the spectrometer. Therefore a calibration of the set-up was performed. The calibration can be used to determine spot temperatures by comparing Stokes and Anti-Stokes spectra. Two different methods are developed to correct for the straylight which is additionally observed in Raman-spectra of YBa 2 Cu 3 O 7 -films. Macro- as well as micro-Raman measurements are used to characterize the film properties, where care has been taken to avoid damages by the laser itself. The macro-Raman set-up is used to identify the properties of the film, such as orientation, oxygen-content and morphology. Outgrowths and other particles on the surface are on the other hand investigated by micro-Raman spectroscopy. The surface morphology is additionally characterized by scanning-electron-microscopy. This is compared to the Raman data. Raman spectra of epitaxial YBa 2 Cu 3 O 7 -films are taken as a function of the temperature and exciting wavelength. The influence on the phonons and on the electronic background is discussed separately. The obtained results are analyzed by comparison with single-crystal measurements. The investigation of YBa 2 Cu 3 O 7 -microbridges in the macro-Raman set-up allows a correlation between the local optical and electrical properties of the bridge. A method is presented which can account for the heating in the laser spot with high accuracy. This method allows to determine local critical current densities as well as local critical temperatures on the microbridge. It provides also the possibility to take Raman spectra at precise spot temperatures. (orig./WL)

Characterization of Surface-Enhanced Raman Scattering of Nicotine Utilizing Plasmonic Nanometals for the Applications of Medical and Chemical Sensing

Science.gov (United States)

Jackson, Ashley; Rigo, Maria; Seo, Jaetae; HU Team

2011-05-01

Raman spectroscopy has received a great deal of interest for its applications in biological sensing and cell imaging due to the ease with which it can be used to extract significant data from tissue and cells. This study has focused on the application of SERS for nicotine detection. Liquid nicotine was diluted and combined with Au nanoparticles (NPs). The nicotine-gold solution was analyzed by acquiring Raman spectra data using a Delta Nu Spectrometer. Absorption data shows the characteristic peak of Au NPs at ~528 nm while showing successful aggregation of the nicotine particles. Data taken from Raman spectra shows characteristic Raman shifts of nicotine at ~1030 cm-1 and ~1590 cm-1. Currently work is being done to optimize the SERS signal for nicotine in the 1590-1600 region using higher concentrations of nicotine and various sizes of Au NPs. This work at Hampton University was supported by the National Science Foundation (HRD-0734635 and HRD-063037).

Fabrication of fine imaging devices using an external proton microbeam

Energy Technology Data Exchange (ETDEWEB)

Sakai, T., E-mail: sakai.takuro@jaea.go.jp [Quantum Beam Science Directorate, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195 (Japan); Yasuda, R.; Iikura, H.; Nojima, T. [Quantum Beam Science Directorate, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195 (Japan); Koka, M.; Satoh, T.; Ishii, Y. [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency (JAEA), Takasaki, Gunma 370-1292 (Japan); Oshima, A. [Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047 (Japan)

2014-08-01

We have successfully fabricated novel microscopic imaging devices made from UV/EB curable resin using an external scanning proton microbeam. The devices are micro-structured fluorescent plates that consist of an array of micro-pillars that align periodically. The base material used in the pillars is UV/EB curable resin and each pillar contains phosphor grains. The pattern exposures were performed using a proton beam writing technique. The height of the pillars depends on the range of the proton beam. Optical microscopy and scanning electron microscopy have been used to characterize the samples. The results show that the fabricated fluorescent plates are expected to be compatible with both spatial resolution and detection efficiency.

Destruction of Raman biosignatures by ionising radiation and the implications for life detection on Mars.

Science.gov (United States)

Dartnell, Lewis R; Page, Kristian; Jorge-Villar, Susana E; Wright, Gary; Munshi, Tasnim; Scowen, Ian J; Ward, John M; Edwards, Howell G M

2012-04-01

Raman spectroscopy has proven to be a very effective approach for the detection of microorganisms colonising hostile environments on Earth. The ExoMars rover, due for launch in 2018, will carry a Raman laser spectrometer to analyse samples of the martian subsurface collected by the probe's 2-m drill in a search for similar biosignatures. The martian surface is unprotected from the flux of cosmic rays, an ionising radiation field that will degrade organic molecules and so diminish and distort the detectable Raman signature of potential martian microbial life. This study employs Raman spectroscopy to analyse samples of two model organisms, the cyanobacterium Synechocystis sp. PCC 6803 and the extremely radiation resistant polyextremophile Deinococcus radiodurans, that have been exposed to increasing doses of ionising radiation. The three most prominent peaks in the Raman spectra are from cellular carotenoids: deinoxanthin in D. radiodurans and β-carotene in Synechocystis. The degradative effect of ionising radiation is clearly seen, with significant diminishment of carotenoid spectral peak heights after 15 kGy and complete erasure of Raman biosignatures by 150 kGy of ionising radiation. The Raman signal of carotenoid in D. radiodurans diminishes more rapidly than that of Synechocystis, believed to be due to deinoxanthin acting as a superior scavenger of radiolytically produced reactive oxygen species, and so being destroyed more quickly than the less efficient antioxidant β-carotene. This study highlights the necessity for further experimental work on the manner and rate of degradation of Raman biosignatures by ionising radiation, as this is of prime importance for the successful detection of microbial life in the martian near subsurface.

Development and preliminary results of an in vivo Raman probe for early lung cancer detection

Science.gov (United States)

Short, Michael A.; Lam, Stephen; McWilliams, Annette; Zhao, Jianhua; Lui, Harvey; Zeng, Haishan

2008-02-01

Our previous results from Raman spectroscopy studies on ex vivo lung tissue showed the technique had great potential to differentiate between samples with different pathologies. In this work, a fast dispersive-type near-infrared (NIR) Raman spectroscopy system was developed to collect real-time, noninvasive, in vivo human lung spectra. The 785 nm excitation, and the collection of tissue emission were accomplished by using a reusable fiber optic catheter which passed down the instrument channel of a bronchoscope. Filters in two stages blocked laser emission other than 785 nm from reaching the tissue surface, and reduced fiber fluorescence and elastically scattered excitation light from being passed to the spectrometer. The spectrometer itself consisted of one of two holographic gratings with usable frequency ranges of: 700 to 2000 cm -1 and 1500 to 3400 cm -1. The dispersed light was detected by a cooled CCD array consisting of 400 by 1340 pixels. To increase the resolution of the system, while maximizing the throughput, a second fiber bundle, consisting of 54×100 μm diameter fibers connected the catheter to the spectrometer. The fibers in this second bundle were spread out to form a parabolic arc which replaced the conventional entrance slit. This geometry corrected for image aberrations, permitting complete CCD vertical binning, thereby yielding up to a 20-fold improvement in signal-to-noise ratio. The estimated spectral resolution of the system was 9 cm -1 for both gratings. So far we have measured spectra from 20 patients and have seen clear differences between spectra from tumor and normal tissue.

Dual-wavelength external cavity laser device for fluorescence suppression in Raman spectroscopy

Science.gov (United States)

Zhang, Xuting; Cai, Zhijian; Wu, Jianhong

2017-10-01

Raman spectroscopy has been widely used in the detection of drugs, pesticides, explosives, food additives and environmental pollutants, for its characteristics of fast measurement, easy sample preparation, and molecular structure analyzing capability. However, fluorescence disturbance brings a big trouble to these applications, with strong fluorescence background covering up the weak Raman signals. Recently shifted excitation Raman difference spectroscopy (SERDS) not only can completely remove the fluorescence background, but also can be easily integrated into portable Raman spectrometers. Usually, SERDS uses two lasers with small wavelength gap to excite the sample, then acquires two spectra, and subtracts one to the other to get the difference spectrum, where the fluorescence background will be rejected. So, one key aspects of successfully applying SERDS method is to obtain a dual-wavelength laser source. In this paper, a dual-wavelength laser device design based on the principles of external cavity diode laser (ECDL) is proposed, which is low-cost and compact. In addition, it has good mechanical stability because of no moving parts. These features make it an ideal laser source for SERDS technique. The experiment results showed that the device can emit narrow-spectral-width lasers of two wavelengths, with the gap smaller than 2 nanometers. The laser power corresponding to each wavelength can be up to 100mW.

Calibration and testing of a Raman hyperspectral imaging system to reveal powdered food adulteration.

Science.gov (United States)

Lohumi, Santosh; Lee, Hoonsoo; Kim, Moon S; Qin, Jianwei; Kandpal, Lalit Mohan; Bae, Hyungjin; Rahman, Anisur; Cho, Byoung-Kwan

2018-01-01

The potential adulteration of foodstuffs has led to increasing concern regarding food safety and security, in particular for powdered food products where cheap ground materials or hazardous chemicals can be added to increase the quantity of powder or to obtain the desired aesthetic quality. Due to the resulting potential health threat to consumers, the development of a fast, label-free, and non-invasive technique for the detection of adulteration over a wide range of food products is necessary. We therefore report the development of a rapid Raman hyperspectral imaging technique for the detection of food adulteration and for authenticity analysis. The Raman hyperspectral imaging system comprises of a custom designed laser illumination system, sensing module, and a software interface. Laser illumination system generates a 785 nm laser line of high power, and the Gaussian like intensity distribution of laser beam is shaped by incorporating an engineered diffuser. The sensing module utilize Rayleigh filters, imaging spectrometer, and detector for collection of the Raman scattering signals along the laser line. A custom-built software to acquire Raman hyperspectral images which also facilitate the real time visualization of Raman chemical images of scanned samples. The developed system was employed for the simultaneous detection of Sudan dye and Congo red dye adulteration in paprika powder, and benzoyl peroxide and alloxan monohydrate adulteration in wheat flour at six different concentrations (w/w) from 0.05 to 1%. The collected Raman imaging data of the adulterated samples were analyzed to visualize and detect the adulterant concentrations by generating a binary image for each individual adulterant material. The results obtained based on the Raman chemical images of adulterants showed a strong correlation (R>0.98) between added and pixel based calculated concentration of adulterant materials. This developed Raman imaging system thus, can be considered as a powerful

Short Distance Standoff Raman Detection of Extra Virgin Olive Oil Adulterated with Canola and Grapeseed Oils.

Science.gov (United States)

Farley, Carlton; Kassu, Aschalew; Bose, Nayana; Jackson-Davis, Armitra; Boateng, Judith; Ruffin, Paul; Sharma, Anup

2017-06-01

A short distance standoff Raman technique is demonstrated for detecting economically motivated adulteration (EMA) in extra virgin olive oil (EVOO). Using a portable Raman spectrometer operating with a 785 nm laser and a 2-in. refracting telescope, adulteration of olive oil with grapeseed oil and canola oil is detected between 1% and 100% at a minimum concentration of 2.5% from a distance of 15 cm and at a minimum concentration of 5% from a distance of 1 m. The technique involves correlating the intensity ratios of prominent Raman bands of edible oils at 1254, 1657, and 1441 cm -1 to the degree of adulteration. As a novel variation in the data analysis technique, integrated intensities over a spectral range of 100 cm -1 around the Raman line were used, making it possible to increase the sensitivity of the technique. The technique is demonstrated by detecting adulteration of EVOO with grapeseed and canola oils at 0-100%. Due to the potential of this technique for making measurements from a convenient distance, the short distance standoff Raman technique has the promise to be used for routine applications in food industry such as identifying food items and monitoring EMA at various checkpoints in the food supply chain and storage facilities.

Infrared and NIR Raman spectroscopy in medical microbiology

Science.gov (United States)

Naumann, Dieter

1998-04-01

FTIR and FT-NIR Raman spectra of intact microbial cells are highly specific, fingerprint-like signatures which can be used to (i) discriminate between diverse microbial species and strains, (ii) detect in situ intracellular components or structures such as inclusion bodies, storage materials or endospores, (iii) detect and quantify metabolically released CO2 in response to various different substrate, and (iv) characterize growth-dependent phenomena and cell-drug interactions. The characteristic information is extracted from the spectral contours by applying resolution enhancement techniques, difference spectroscopy, and pattern recognition methods such as factor-, cluster-, linear discriminant analysis, and artificial neural networks. Particularly interesting applications arise by means of a light microscope coupled to the spectrometer. FTIR spectra of micro-colonies containing less than 103 cells can be obtained from colony replica by a stamping technique that transfers micro-colonies growing on culture plates to a special IR-sample holder. Using a computer controlled x, y- stage together with mapping and video techniques, the fundamental tasks of microbiological analysis, namely detection, enumeration, and differentiation of micro- organisms can be integrated in one single apparatus. FTIR and NIR-FT-Raman spectroscopy can also be used in tandem to characterize medically important microorganisms. Currently novel methodologies are tested to take advantage of the complementary information of IR and Raman spectra. Representative examples on medically important microorganisms will be given that highlight the new possibilities of vibrational spectroscopies.

Physics study of microbeam radiation therapy with PSI-version of Monte Carlo code GEANT as a new computational tool

CERN Document Server

Stepanek, J; Laissue, J A; Lyubimova, N; Di Michiel, F; Slatkin, D N

2000-01-01

Microbeam radiation therapy (MRT) is a currently experimental method of radiotherapy which is mediated by an array of parallel microbeams of synchrotron-wiggler-generated X-rays. Suitably selected, nominally supralethal doses of X-rays delivered to parallel microslices of tumor-bearing tissues in rats can be either palliative or curative while causing little or no serious damage to contiguous normal tissues. Although the pathogenesis of MRT-mediated tumor regression is not understood, as in all radiotherapy such understanding will be based ultimately on our understanding of the relationships among the following three factors: (1) microdosimetry, (2) damage to normal tissues, and (3) therapeutic efficacy. Although physical microdosimetry is feasible, published information on MRT microdosimetry to date is computational. This report describes Monte Carlo-based computational MRT microdosimetry using photon and/or electron scattering and photoionization cross-section data in the 1 e V through 100 GeV range distrib...

Bystander effect studies using heavy-ion microbeam

International Nuclear Information System (INIS)

Kobayashi, Yasuhiko; Funayama, Tomoo; Sakashita, Tetsuya; Wada, Seiichi; Yokota, Yuichiro; Kakizaki, Takehiko; Hamada, Nobuyuki; Hara, Takamitsu; Fukamoto, Kana; Suzuki, Michiyo; Ni, M.; Furusawa, Yoshiya

2007-01-01

We have established a single cell irradiation system, which allows selected cells to be individually hit with defined number of heavy charged particles, using a collimated heavy-ion microbeam apparatus at JAEA-Takasaki. This system has been developed to study radiobiological processes in hit cells and bystander cells exposed to low dose and low dose-rate high-LET radiations, in ways that cannot be achieved using conventional broad-field exposures. Individual cultured cells grown in special dishes were irradiated in the atmosphere with a single or defined numbers of 18.3 MeV/amu 12 C, 13.0 or 17.5 MeV/amu 20 Ne, and 11.5 MeV/amu 40 Ar ions. Targeting and irradiation of the cells were performed automatically according to the positional data of the target cells microscopically obtained before irradiation. The actual number of particle tracks that pass through target cells was detected with prompt etching of the bottom of the cell dish made of ion track detector TNF-1 (modified CR-39). (author)

Raman microspectroscopy, surface-enhanced Raman scattering microspectroscopy, and stable-isotope Raman microspectroscopy for biofilm characterization.

Science.gov (United States)

Ivleva, Natalia P; Kubryk, Patrick; Niessner, Reinhard

2017-07-01

Biofilms represent the predominant form of microbial life on our planet. These aggregates of microorganisms, which are embedded in a matrix formed by extracellular polymeric substances, may colonize nearly all interfaces. Detailed knowledge of microorganisms enclosed in biofilms as well as of the chemical composition, structure, and functions of the complex biofilm matrix and their changes at different stages of the biofilm formation and under various physical and chemical conditions is relevant in different fields. Important research topics include the development and improvement of antibiotics and medical devices and the optimization of biocides, antifouling strategies, and biological wastewater treatment. Raman microspectroscopy is a capable and nondestructive tool that can provide detailed two-dimensional and three-dimensional chemical information about biofilm constituents with the spatial resolution of an optical microscope and without interference from water. However, the sensitivity of Raman microspectroscopy is rather limited, which hampers the applicability of Raman microspectroscopy especially at low biomass concentrations. Fortunately, the resonance Raman effect as well as surface-enhanced Raman scattering can help to overcome this drawback. Furthermore, the combination of Raman microspectroscopy with other microscopic techniques, mass spectrometry techniques, or particularly with stable-isotope techniques can provide comprehensive information on monospecies and multispecies biofilms. Here, an overview of different Raman microspectroscopic techniques, including resonance Raman microspectroscopy and surface-enhanced Raman scattering microspectroscopy, for in situ detection, visualization, identification, and chemical characterization of biofilms is given, and the main feasibilities and limitations of these techniques in biofilm research are presented. Future possibilities of and challenges for Raman microspectroscopy alone and in combination with other

Development of a Fiber-Optics Microspatially Offset Raman Spectroscopy Sensor for Probing Layered Materials.

Science.gov (United States)

Vandenabeele, Peter; Conti, Claudia; Rousaki, Anastasia; Moens, Luc; Realini, Marco; Matousek, Pavel

2017-09-05

Microspatially offset Raman spectroscopy (micro-SORS) has been proposed as a valuable approach to sample molecular information from layers that are covered by a turbid (nontransparent) layer. However, when large magnifications are involved, the approach is not straightforward, as spatial constraints exist to position the laser beam and the objective lens with the external beam delivery or, with internal beam delivery, the maximum spatial offset achievable is restricted. To overcome these limitations, we propose here a prototype of a new micro-SORS sensor, which uses bare glass fibers to transfer the laser radiation to the sample and to collect the Raman signal from a spatially offset zone to the Raman spectrometer. The concept also renders itself amenable to remote delivery and to the miniaturization of the probe head which could be beneficial for special applications, e.g., where access to sample areas is restricted. The basic applicability of this approach was demonstrated by studying several layered structure systems. Apart from proving the feasibility of the technique, also, practical aspects of the use of the prototype sensor are discussed.

Rapid detection of bacterial contamination in cell or tissue cultures based on Raman spectroscopy

Science.gov (United States)

Bolwien, Carsten; Sulz, Gerd; Becker, Sebastian; Thielecke, Hagen; Mertsching, Heike; Koch, Steffen

2008-02-01

Monitoring the sterility of cell or tissue cultures is an essential task, particularly in the fields of regenerative medicine and tissue engineering when implanting cells into the human body. We present a system based on a commercially available microscope equipped with a microfluidic cell that prepares the particles found in the solution for analysis, a Raman-spectrometer attachment optimized for non-destructive, rapid recording of Raman spectra, and a data acquisition and analysis tool for identification of the particles. In contrast to conventional sterility testing in which samples are incubated over weeks, our system is able to analyze milliliters of supernatant or cell suspension within hours by filtering relevant particles and placing them on a Raman-friendly substrate in the microfluidic cell. Identification of critical particles via microscopic imaging and subsequent image analysis is carried out before micro-Raman analysis of those particles is then carried out with an excitation wavelength of 785 nm. The potential of this setup is demonstrated by results of artificial contamination of samples with a pool of bacteria, fungi, and spores: single-channel spectra of the critical particles are automatically baseline-corrected without using background data and classified via hierarchical cluster analysis, showing great promise for accurate and rapid detection and identification of contaminants.

3D mapping of individual cells using a proton microbeam

International Nuclear Information System (INIS)

Michelet, C.; Moretto, Ph.

1999-01-01

Various imaging techniques carried out with a nuclear microprobe make it possible to reveal by 2D mapping, the internal structure of isolated cells. An improvement of those techniques allows today 3D mapping of cells. STIM- and PIXE-Tomography have been recently implemented on the CENBG microbeam line. The performance offered by these methods, which are capable of resolving objects having diameters less then 100 μm, has been validated on reference specimens and on human cells from cultures. In addition to the fineness of the resolution, these techniques offer the advantage of performing volume analyses without prior cutting of the samples. The ultimate aim of this program of research is to perform 3D elemental chemical analysis of individual cells in the field of biomedicine

Making microbeams and nanobeams by channeling in microstructures and nanostructures

Directory of Open Access Journals (Sweden)

S. Bellucci

2003-03-01

Full Text Available A particle beam of very small cross section is useful in many accelerator applications including biological and medical ones. We show the capability of the channeling technique using a micron-sized structure on a surface of a single crystal, or using a nanotube, to produce a beam of a cross section down to one square micrometer (or nanometer. The channeled beam can be deflected and thus well separated in angle and space from the primary and scattered particles. Monte Carlo simulation is done to evaluate the characteristics of a channeled microbeam. Emittances down to 0.001 nm rad, and flux up to 10^{6}   μm^{2} per second, can be achieved for protons and ions.

Quantifying creatinine and urea in human urine through Raman spectroscopy aiming at diagnosis of kidney disease

Science.gov (United States)

Saatkamp, Cassiano Junior; de Almeida, Maurício Liberal; Bispo, Jeyse Aliana Martins; Pinheiro, Antonio Luiz Barbosa; Fernandes, Adriana Barrinha; Silveira, Landulfo, Jr.

2016-03-01

Due to their importance in the regulation of metabolites, the kidneys need continuous monitoring to check for correct functioning, mainly by urea and creatinine urinalysis. This study aimed to develop a model to estimate the concentrations of urea and creatinine in urine by means of Raman spectroscopy (RS) that could be used to diagnose kidney disease. Midstream urine samples were obtained from 54 volunteers with no kidney complaints. Samples were subjected to a standard colorimetric assay of urea and creatinine and submitted to spectroscopic analysis by means of a dispersive Raman spectrometer (830 nm, 350 mW, 30 s). The Raman spectra of urine showed peaks related mainly to urea and creatinine. Partial least squares models were developed using selected Raman bands related to urea and creatinine and the biochemical concentrations in urine measured by the colorimetric method, resulting in r=0.90 and 0.91 for urea and creatinine, respectively, with root mean square error of cross-validation (RMSEcv) of 312 and 25.2 mg/dL, respectively. RS may become a technique for rapid urinalysis, with concentration errors suitable for population screening aimed at the prevention of renal diseases.

Micro-raman and tip-enhanced raman spectroscopy of carbon allotropes

NARCIS (Netherlands)

Hoffmann, G.G.; With, de G.; Loos, J.

2008-01-01

Raman spectroscopic data are obtained on various carbon allotropes like diamond, amorphous carbon, graphite, graphene and single wall carbon nanotubes by micro-Raman spectroscopy, tip-enhanced Raman spectroscopy and tip-enhanced Raman spectroscopy imaging, and the potentials of these techniques for

Radiobiological experiments at the Munich ion microbeam SNAKE

Energy Technology Data Exchange (ETDEWEB)

Friedl, A.A.; Drexler, G.A.; Loewe, R. [Strahlenbiologisches Inst., Ludwig-Maximilians-Univ. Muenchen (Germany); Dollinger, G.; Hauptner, A.; Hable, V.; Greubel, C.; Kruecken, R. [Physik Dept. E12, Technische Univ. Muenchen, Garching (Germany); Cremer, T.; Dietzel, S. [Dept. Biologie II, Ludwig-Maximilians-Univ. Muenchen, Planegg-Martinsried (Germany)

2005-07-01

The ion microbeam SNAKE at the Munich 14 MV tandem accelerator was recently adapted for irradiation of cells and is now routinely used for radiobiological experiments. Several features, including ion-optical beam focussing to achieve a targeting accuracy of about 500 nm, fast movement of the beam by electrostatic deflection and single ion preparation make SNAKE an excellent tool for localized irradiation with a defined number of ions. The ion spectrum available ranges from 20 MeV protons to 200 MeV gold ions, thus allowing to vary the LET over four orders of magnitude and to conduct low and high LET irradiation in a single experimental set-up. This offers the possibility of a systematic analysis of the cellular response mechanisms in their dependence on dose and LET. Other current lines of research include analysis of the spatio-temporal dynamics of protein recruitment at damaged chromatin sites and determination of the mobility of damaged chromatin regions in the interphase nucleus. (orig.)

A new external microbeam system in Fudan University

International Nuclear Information System (INIS)

Zheng, Y.; Shen, H.; Li, Y.Q.; Li, X.Y.; Yang, M.J.; Mi, Y.

2013-01-01

A cost-effective and removable external beam system is set up based on the Oxford Microbeam system in Fudan University. In our external beam system, 7.5-μm-thick Kapton film is used as exit window with a diameter of 3.5 mm. The spatial resolution is about 18 μm full width at half maximum (FWHM) on a copper grid. As an example, calcium distribution in otolith is present by the external micro-PIXE. In addition, little change can be done to the external system mentioned above for radiobiology experiments. The exit window can be changed from the focal plane to the observation window of vacuum chamber. By calculation, the beam spot size can reach less than 30 μm. Since the Oxford type octagonal target chamber is popular among the nuclear microprobe facilities, this method can be provided to easily replace the in-vacuum system with the external system, extending the in-vacuum analysis to external beam analysis

A new external microbeam system in Fudan University

Energy Technology Data Exchange (ETDEWEB)

Zheng, Y.; Shen, H., E-mail: haoshen@fudan.edu.cn; Li, Y.Q.; Li, X.Y.; Yang, M.J.; Mi, Y.

2013-07-01

A cost-effective and removable external beam system is set up based on the Oxford Microbeam system in Fudan University. In our external beam system, 7.5-μm-thick Kapton film is used as exit window with a diameter of 3.5 mm. The spatial resolution is about 18 μm full width at half maximum (FWHM) on a copper grid. As an example, calcium distribution in otolith is present by the external micro-PIXE. In addition, little change can be done to the external system mentioned above for radiobiology experiments. The exit window can be changed from the focal plane to the observation window of vacuum chamber. By calculation, the beam spot size can reach less than 30 μm. Since the Oxford type octagonal target chamber is popular among the nuclear microprobe facilities, this method can be provided to easily replace the in-vacuum system with the external system, extending the in-vacuum analysis to external beam analysis.

A new external microbeam system in Fudan University

Energy Technology Data Exchange (ETDEWEB)

Zheng, Y. [Applied Ion Beam Physics Laboratory, Institute of Modern Physics, Fudan University, Shanghai 200433 (China); Shen, H., E-mail: haoshen@fudan.edu.cn [Applied Ion Beam Physics Laboratory, Institute of Modern Physics, Fudan University, Shanghai 200433 (China); Li, Y.Q.; Li, X.Y.; Yang, M.J.; Mi, Y. [Applied Ion Beam Physics Laboratory, Institute of Modern Physics, Fudan University, Shanghai 200433 (China)

2013-02-01

A cost-effective and removable external beam system is set up based on the Oxford Microbeam system in Fudan University. In our external beam system, 7.5-μm-thick Kapton film is used as exit window with a diameter of 3.5 mm. The spatial resolution is about 18 μm full width at half maximum (FWHM) on a copper grid. As an example, calcium distribution in otolith is present by the external micro-PIXE. In addition, little change can be done to the external system mentioned above for radiobiology experiments. The exit window can be changed from the focal plane to the observation window of vacuum chamber. By calculation, the beam spot size can reach less than 30 μm. Since the Oxford type octagonal target chamber is popular among the nuclear microprobe facilities, this method can be provided to easily replace the in-vacuum system with the external system, extending the in-vacuum analysis to external beam analysis.

Paintings on copper by the Flemish artist Frans Francken II: PIXE characterization by external microbeam

International Nuclear Information System (INIS)

Corregidor, V.; Oliveira, A.R.; Rodrigues, P.A.; Alves, L.C.

2015-01-01

Resorting to an external proton microbeam, PIXE analyses of three oil paintings on copper support dated from the XVII century and attributed to the Flemish artist Frans Francken II, were undertaken. The present work aims to contribute to the compositional study of the painting materials employed by XVII century artists that exploited copper as a support for oil painting, and specifically the materials used by Francken’s workshop, particularly copper plates. Because of the low thickness of the pictorial layers of this type of paintings and its non-destructive character, PIXE is the ideal technique to study the elemental composition of the paintings. Several spots in each painting were chosen for analysis in order to cover almost all the pigments used in the colour palette. Lead and calcium were detected in practically every analysed regions, probably related to the presence of lead white and chalk, usually used as ground layer on copper paintings. Small quantities of gold were also detected, which is present in many of this artist’s works to embellish some details of the representations. Also this work reports the first application of the external proton microbeam set-up available at CTN/IST in Portugal for the characterization of oil paintings

Branch formation induced by microbeam irradiation of Adiantum protonemata

International Nuclear Information System (INIS)

Wada, M.

1998-01-01

Branches were induced in centrifuged Adiantum protonemal cells by partial irradiation with polarized red light. Nuclear behavior and microtubule pattern change during branch formation were investigated. A branch formed at any part where a red microbeam was focused along a long apical cell. The nucleus moved towards the irradiated area and remained there until a branch developed. The pattern of microtubules changed from parallel to oblique at the irradiated area and then a transverse arrangement of microtubules appeared on both sides of the area. It appeared as if the nucleus was suspended between two microtubule rings. This nuclear behavior and the changes in microtubule pattern were different from those observed during branch formation under whole cell irradiation. From the results of this work we suggest that there is an importance for precise control of experimental conditions

Screening and staging for non-small cell lung cancer by serum laser Raman spectroscopy.

Science.gov (United States)

Wang, Hong; Zhang, Shaohong; Wan, Limei; Sun, Hong; Tan, Jie; Su, Qiucheng

2018-08-05

Lung cancer is the leading cause of cancer-related death worldwide. Current clinical screening methods to detect lung cancer are expensive and associated with many complications. Raman spectroscopy is a spectroscopic technique that offers a convenient method to gain molecular information about biological samples. In this study, we measured the serum Raman spectral intensity of healthy volunteers and patients with different stages of non-small cell lung cancer. The purpose of this study was to evaluate the application of serum laser Raman spectroscopy as a low cost alternative method in the screening and staging of non-small cell lung cancer (NSCLC). The Raman spectra of the sera of peripheral venous blood were measured with a LabRAM HR 800 confocal Micro Raman spectrometer for individuals from five groups including 14 healthy volunteers (control group), 23 patients with stage I NSCLC (stage I group), 24 patients with stage II NSCLC (stage II group), 19 patients with stage III NSCLC (stage III group), 11 patients with stage IV NSCLC (stage IV group). Each serum sample was measured 3 times at different spots and the average spectra represented the signal of Raman spectra in each case. The Raman spectrum signal data of the five groups were statistically analyzed by analysis of variance (ANOVA), principal component analysis (PCA), linear discriminant analysis (LDA), and cross-validation. Raman spectral intensity was sequentially reduced in serum samples from control group, stage I group, stage II group and stage III/IV group. The strongest peak intensity was observed in the control group, and the weakest one was found in the stage III/IV group at bands of 848 cm -1 , 999 cm -1 , 1152 cm -1 , 1446 cm -1 and 1658 cm -1 (P Raman spectroscopy can effectively identify patients with stage I, stage II or stage III/IV Non-Small Cell Lung cancer using patient serum samples. Copyright © 2018 Elsevier B.V. All rights reserved.

Raman spectroscopy and the forensic analysis of black/grey and blue cotton fibres Part 1: investigation of the effects of varying laser wavelength.

Science.gov (United States)

Thomas, J; Buzzini, P; Massonnet, G; Reedy, B; Roux, C

2005-09-10

Raman spectroscopy was investigated to determine the optimal conditions, mainly laser wavelength/s, for the analysis of the commonly encountered black/grey and blue cotton fibres dyed with reactive dyes. In this first part, a single blue cotton fibre, its three dye components, and an undyed cotton fibre were analysed with five different laser wavelengths from two different Raman microprobe spectrometers. The quality of the spectra, fibre degradation and speed of acquisition were used to determine that, under the conditions used, the 785 and 830 nm lasers gave superior results. The 632.8 nm laser wavelengths provided good results with little acquisition time and no spectral degradation. Results indicate that, at least, the major dye component could be identified using Raman spectroscopy.

Benchmarking and validation of a Geant4-SHADOW Monte Carlo simulation for dose calculations in microbeam radiation therapy.

Science.gov (United States)

Cornelius, Iwan; Guatelli, Susanna; Fournier, Pauline; Crosbie, Jeffrey C; Sanchez Del Rio, Manuel; Bräuer-Krisch, Elke; Rosenfeld, Anatoly; Lerch, Michael

2014-05-01

Microbeam radiation therapy (MRT) is a synchrotron-based radiotherapy modality that uses high-intensity beams of spatially fractionated radiation to treat tumours. The rapid evolution of MRT towards clinical trials demands accurate treatment planning systems (TPS), as well as independent tools for the verification of TPS calculated dose distributions in order to ensure patient safety and treatment efficacy. Monte Carlo computer simulation represents the most accurate method of dose calculation in patient geometries and is best suited for the purpose of TPS verification. A Monte Carlo model of the ID17 biomedical beamline at the European Synchrotron Radiation Facility has been developed, including recent modifications, using the Geant4 Monte Carlo toolkit interfaced with the SHADOW X-ray optics and ray-tracing libraries. The code was benchmarked by simulating dose profiles in water-equivalent phantoms subject to irradiation by broad-beam (without spatial fractionation) and microbeam (with spatial fractionation) fields, and comparing against those calculated with a previous model of the beamline developed using the PENELOPE code. Validation against additional experimental dose profiles in water-equivalent phantoms subject to broad-beam irradiation was also performed. Good agreement between codes was observed, with the exception of out-of-field doses and toward the field edge for larger field sizes. Microbeam results showed good agreement between both codes and experimental results within uncertainties. Results of the experimental validation showed agreement for different beamline configurations. The asymmetry in the out-of-field dose profiles due to polarization effects was also investigated, yielding important information for the treatment planning process in MRT. This work represents an important step in the development of a Monte Carlo-based independent verification tool for treatment planning in MRT.

Role of the micronucleus in stomatogenesis in sexual reproduction of Paramecium tetraurelia: laser microbeam irradiation of the micronucleus

Energy Technology Data Exchange (ETDEWEB)

Tam Laiwa; Ng, S.F.

1986-12-01

Fifteen amicronucleate cell lines and 22 cell lines with defective micronuclei were obtained following selective laser microbeam irradiation of the micronucleus. The amicronucleate cell lines showed reduced growth rate and formed abnormal oral apparatuses in asexual reproduction, and failed to produce any oral apparatus in autogamy. The 22 cell lines with defective micronucleus exhibited various abnormalities of the oral apparatus newly formed during autogamy. These abnormalities included the arrest of membranelle assembly, reduction in the length of the buccal cavity and oral membranelles, disruption of the organization of the membranelles, quadrulation of the dorsal peniculus, and failure of addition of membranellar basal body rows. Hence the micronucleus plays multiple roles in sexual stomatogenesis. Our results agree with the notion that the micronucleus acts during a critical period between the second meiotic division and up to the formation of the zygotic nucleus to control the early stage of oral membranelle assembly. Laser microbeam irradiation might have created recessive mutations and/or chromosomal aberrations, which were expressed during this critical period with the formation of abnormal postmeiotic nuclei.

Vibration analysis of rotating functionally graded Timoshenko microbeam based on modified couple stress theory under different temperature distributions

Science.gov (United States)

Ghadiri, Majid; Shafiei, Navvab

2016-04-01

In this study, thermal vibration of rotary functionally graded Timoshenko microbeam has been analyzed based on modified couple stress theory considering temperature change in four types of temperature distribution on thermal environment. Material properties of FG microbeam are supposed to be temperature dependent and vary continuously along the thickness according to the power-law form. The axial forces are also included in the model as the thermal and true spatial variation due to the rotation. Governing equations and boundary conditions have been derived by employing Hamiltonian's principle. The differential quadrature method is employed to solve the governing equations for cantilever and propped cantilever boundary conditions. Validations are done by comparing available literatures and obtained results which indicate accuracy of applied method. Results represent effects of temperature changes, different boundary conditions, nondimensional angular velocity, length scale parameter, different boundary conditions, FG index and beam thickness on fundamental, second and third nondimensional frequencies. Results determine critical values of temperature changes and other essential parameters which can be applicable to design micromachines like micromotor and microturbine.

Detection of pigments of halophilic endoliths from gypsum: Raman portable instrument and European Space Agency's prototype analysis

Science.gov (United States)

Culka, Adam; Osterrothová, Kateřina; Hutchinson, Ian; Ingley, Richard; McHugh, Melissa; Oren, Aharon; Edwards, Howell G. M.; Jehlička, Jan

2014-01-01

A prototype instrument, under development at the University of Leicester, for the future European Space Agency (ESA) ExoMars mission, was used for the analysis of microbial pigments within a stratified gypsum crust from a hypersaline saltern evaporation pond at Eilat (Israel). Additionally, the same samples were analysed using a miniaturized Raman spectrometer, featuring the same 532 nm excitation. The differences in the position of the specific bands, attributed to carotenoid pigments from different coloured layers, were minor when analysed by the ESA prototype instrument; therefore, making it difficult to distinguish among the different pigments. The portable Delta Nu Advantage instrument allowed for the discrimination of microbial carotenoids from the orange/green and purple layers. The purpose of this study was to complement previous laboratory results with new data and experience with portable or handheld Raman systems, even with a dedicated prototype Raman system for the exploration of Mars. The latter is equipped with an excitation wavelength falling within the carotenoid polyene resonance region. The ESA prototype Raman instrument detected the carotenoid pigments (biomarkers) with ease, although further detailed distinctions among them were not achieved. PMID:25368354

Detection of pigments of halophilic endoliths from gypsum: Raman portable instrument and European Space Agency's prototype analysis.

Science.gov (United States)

Culka, Adam; Osterrothová, Kateřina; Hutchinson, Ian; Ingley, Richard; McHugh, Melissa; Oren, Aharon; Edwards, Howell G M; Jehlička, Jan

2014-12-13

A prototype instrument, under development at the University of Leicester, for the future European Space Agency (ESA) ExoMars mission, was used for the analysis of microbial pigments within a stratified gypsum crust from a hypersaline saltern evaporation pond at Eilat (Israel). Additionally, the same samples were analysed using a miniaturized Raman spectrometer, featuring the same 532 nm excitation. The differences in the position of the specific bands, attributed to carotenoid pigments from different coloured layers, were minor when analysed by the ESA prototype instrument; therefore, making it difficult to distinguish among the different pigments. The portable Delta Nu Advantage instrument allowed for the discrimination of microbial carotenoids from the orange/green and purple layers. The purpose of this study was to complement previous laboratory results with new data and experience with portable or handheld Raman systems, even with a dedicated prototype Raman system for the exploration of Mars. The latter is equipped with an excitation wavelength falling within the carotenoid polyene resonance region. The ESA prototype Raman instrument detected the carotenoid pigments (biomarkers) with ease, although further detailed distinctions among them were not achieved. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Raman spectroscopy

Science.gov (United States)

Raman spectroscopy has gained increased use and importance in recent years for accurate and precise detection of physical and chemical properties of food materials, due to the greater specificity and sensitivity of Raman techniques over other analytical techniques. This book chapter presents Raman s...

Spherical grating spectrometers

Science.gov (United States)

O'Donoghue, Darragh; Clemens, J. Christopher

2014-07-01

We describe designs for spectrometers employing convex dispersers. The Offner spectrometer was the first such instrument; it has almost exclusively been employed on satellite platforms, and has had little impact on ground-based instruments. We have learned how to fabricate curved Volume Phase Holographic (VPH) gratings and, in contrast to the planar gratings of traditional spectrometers, describe how such devices can be used in optical/infrared spectrometers designed specifically for curved diffraction gratings. Volume Phase Holographic gratings are highly efficient compared to conventional surface relief gratings; they have become the disperser of choice in optical / NIR spectrometers. The advantage of spectrometers with curved VPH dispersers is the very small number of optical elements used (the simplest comprising a grating and a spherical mirror), as well as illumination of mirrors off axis, resulting in greater efficiency and reduction in size. We describe a "Half Offner" spectrometer, an even simpler version of the Offner spectrometer. We present an entirely novel design, the Spherical Transmission Grating Spectrometer (STGS), and discuss exemplary applications, including a design for a double-beam spectrometer without any requirement for a dichroic. This paradigm change in spectrometer design offers an alternative to all-refractive astronomical spectrometer designs, using expensive, fragile lens elements fabricated from CaF2 or even more exotic materials. The unobscured mirror layout avoids a major drawback of the previous generation of catadioptric spectrometer designs. We describe laboratory measurements of the efficiency and image quality of a curved VPH grating in a STGS design, demonstrating, simultaneously, efficiency comparable to planar VPH gratings along with good image quality. The stage is now set for construction of a prototype instrument with impressive performance.

Subfemtosecond pulse generation by cascade-stimulated Raman scattering with modulated Raman excitation

International Nuclear Information System (INIS)

Wu Kun; Wu Jian; Zeng Heping

2003-01-01

Subfemtosecond (sub-fs) pulses can be generated by cascade-stimulated Raman scattering in a Raman medium with modulated Raman excitations, driven by two sufficiently intense laser beams, one of which is amplitude modulated. The nonadiabatic Raman interaction establishes a strong modulated Raman coherence, which supports compression of the generated broadband Raman sidebands to a train of sub-fs pulses regardless of whether the carrier frequencies of the driving lasers are tuned above, below or on two-photon Raman resonance. (letter to the editor)

FT-Raman spectroscopic study of calcium-rich and magnesium-rich carbonate minerals.

Science.gov (United States)

Edwards, Howell G M; Villar, Susana E Jorge; Jehlicka, Jan; Munshi, Tasnim

2005-08-01

Calcium and magnesium carbonates are important minerals found in sedimentary environments. Although sandstones are the most common rock colonized by endolith organisms, the production of calcium and magnesium carbonates is important in survival strategies of organisms and as a source for the removal of oxalate ions. Extremophile organisms in some situations may convert or destroy carbonates of calcium and magnesium, which gives important information about the conditions under which these organisms can survive. The identification on the surface of Mars of 'White Rock' formations, in Juventae Chasma or Sabaea Terra, as possibly carbonate rocks makes the study of these minerals a prerequisite of remote Martian exploration. Here, we show the protocol for the identification by Raman spectroscopy of different calcium and magnesium carbonates and we present a database of relevance in the search for life, extinct or extant, on Mars; this will be useful for the assessment of data obtained from remote, miniaturized Raman spectrometers now proposed for Mars exploration.

Nuclear microbeam study of advanced materials for fusion reactor technology

International Nuclear Information System (INIS)

Alves, L.C.; Alves, E.; Grime, G.W.; Silva, M.F. da; Soares, J.C.

1999-01-01

The Oxford scanning proton microprobe was used to study SiC fibres, SiC/SiC ceramic composites and Be pebbles, which are some of the most important materials for fusion technology. For the SiC materials, although the results reveal a high degree of homogeneity and purity in the composition of the fibres, some grains containing heavy metals were detected in the composites. Rutherford backscattering analysis further allowed establishing that at least some of these grains are not on the surface of the material but rather distributed throughout the bulk of the SiC composites. The two different types of Be pebbles analysed also showed very different levels of contaminants. The information obtained with the microbeam analysis is confronted with the one resulting from the broad beam PIXE and RBS analysis

Raman Plus X: Biomedical Applications of Multimodal Raman Spectroscopy.

Science.gov (United States)

Das, Nandan K; Dai, Yichuan; Liu, Peng; Hu, Chuanzhen; Tong, Lieshu; Chen, Xiaoya; Smith, Zachary J

2017-07-07

Raman spectroscopy is a label-free method of obtaining detailed chemical information about samples. Its compatibility with living tissue makes it an attractive choice for biomedical analysis, yet its translation from a research tool to a clinical tool has been slow, hampered by fundamental Raman scattering issues such as long integration times and limited penetration depth. In this review we detail the how combining Raman spectroscopy with other techniques yields multimodal instruments that can help to surmount the translational barriers faced by Raman alone. We review Raman combined with several optical and non-optical methods, including fluorescence, elastic scattering, OCT, phase imaging, and mass spectrometry. In each section we highlight the power of each combination along with a brief history and presentation of representative results. Finally, we conclude with a perspective detailing both benefits and challenges for multimodal Raman measurements, and give thoughts on future directions in the field.

Non-contact temperature Raman measurement in YSZ and alumina ceramics

Science.gov (United States)

Thapa, Juddha; Chorpening, Benjamin T.; Buric, Michael P.

2018-02-01

Yttria-stabilized zirconia (YSZ: ZrO2 + Y2O3) and alumina (Al2O3) are widely used in high-temperature applications due to their high-temperature stability, low thermal conductivity, and chemical inertness. Alumina is used extensively in engineered ceramic applications such as furnace tubes and thermocouple protection tubes, while YSZ is commonly used in thermal barrier coatings on turbine blades. Because they are already often found in high temperature and combustion applications, these two substances have been compared as candidates for Raman thermometry in high-temperature energy-related applications. Both ceramics were used with as-received rough surfaces, i.e., without polishing or modification. This closely approximates surface conditions in practical high-temperature situations. A single-line argon ion laser at 488nm was used to excite the materials inside a cylindrical furnace while measuring Raman spectra with a fixed-grating spectrometer. The shift in the peak positions of the most intense A1g peak at 418cm-1 (room temperature position) of alumina ceramic and relatively more symmetric Eg peak at 470cm-1 (room temperature position) of YSZ were measured and reported along with a thermocouple-derived reference temperature up to about 1000°C. This study showed that alumina and YSZ ceramics can be used in high-temperature Raman thermometry with an accuracy of 4.54°C and 10.5°C average standard deviations respectively over the range of about 1000°C. We hope that this result will guide future researchers in selecting materials and utilizing Raman non-contact temperature measurements in harsh environments.

Near-infrared Raman spectroscopy to detect anti-Toxoplasma gondii antibody in blood sera of domestic cats: quantitative analysis based on partial least-squares multivariate statistics

Science.gov (United States)

Duarte, Janaína; Pacheco, Marcos T. T.; Villaverde, Antonio Balbin; Machado, Rosangela Z.; Zângaro, Renato A.; Silveira, Landulfo

2010-07-01

Toxoplasmosis is an important zoonosis in public health because domestic cats are the main agents responsible for the transmission of this disease in Brazil. We investigate a method for diagnosing toxoplasmosis based on Raman spectroscopy. Dispersive near-infrared Raman spectra are used to quantify anti-Toxoplasma gondii (IgG) antibodies in blood sera from domestic cats. An 830-nm laser is used for sample excitation, and a dispersive spectrometer is used to detect the Raman scattering. A serological test is performed in all serum samples by the enzyme-linked immunosorbent assay (ELISA) for validation. Raman spectra are taken from 59 blood serum samples and a quantification model is implemented based on partial least squares (PLS) to quantify the sample's serology by Raman spectra compared to the results provided by the ELISA test. Based on the serological values provided by the Raman/PLS model, diagnostic parameters such as sensitivity, specificity, accuracy, positive prediction values, and negative prediction values are calculated to discriminate negative from positive samples, obtaining 100, 80, 90, 83.3, and 100%, respectively. Raman spectroscopy, associated with the PLS, is promising as a serological assay for toxoplasmosis, enabling fast and sensitive diagnosis.

An ultra-thin Schottky diode as a transmission particle detector for biological microbeams

International Nuclear Information System (INIS)

Grad, M; Harken, A; Randers-Pehrson, G; Brenner, D J; Attinger, D

2012-01-01

We fabricated ultrathin metal-semiconductor Schottky diodes for use as transmission particle detectors in the biological microbeam at Columbia University's Radiological Research Accelerator Facility (RARAF). The RARAF microbeam can deliver a precise dose of ionizing radiation in cell nuclei with sub-micron precision. To ensure an accurate delivery of charged particles, the facility currently uses a commercial charged-particle detector placed after the sample. We present here a transmission detector that will be placed between the particle accelerator and the biological specimen, allowing the irradiation of samples that would otherwise block radiation from reaching a detector behind the sample. Four detectors were fabricated with co-planar gold and aluminum electrodes thermally evaporated onto etched n-type crystalline silicon substrates, with device thicknesses ranging from 8.5 μm - 13.5 μm. We show coincident detections and pulse-height distributions of charged particles in both the transmission detector and the commercial detector above it. Detections are demonstrated at a range of operating conditions, including incoming particle type, count rate, and beam location on the detectors. The 13.5 μm detector is shown to work best to detect 2.7 MeV protons (H + ), and the 8.5 μm detector is shown to work best to detect 5.4 MeV alpha particles ( 4 He ++ ). The development of a transmission detector enables a range of new experiments to take place at RARAF on radiation-stopping samples such as thick tissues, targets that need immersion microscopy, and integrated microfluidic devices for handling larger quantities of cells and small organisms.

An ultra-thin Schottky diode as a transmission particle detector for biological microbeams

Science.gov (United States)

Harken, Andrew; Randers-Pehrson, Gerhard; Attinger, Daniel; Brenner, David J.

2013-01-01

We fabricated ultrathin metal-semiconductor Schottky diodes for use as transmission particle detectors in the biological microbeam at Columbia University’s Radiological Research Accelerator Facility (RARAF). The RARAF microbeam can deliver a precise dose of ionizing radiation in cell nuclei with sub-micron precision. To ensure an accurate delivery of charged particles, the facility currently uses a commercial charged-particle detector placed after the sample. We present here a transmission detector that will be placed between the particle accelerator and the biological specimen, allowing the irradiation of samples that would otherwise block radiation from reaching a detector behind the sample. Four detectors were fabricated with co-planar gold and aluminum electrodes thermally evaporated onto etched n-type crystalline silicon substrates, with device thicknesses ranging from 8.5 μm – 13.5 μm. We show coincident detections and pulse-height distributions of charged particles in both the transmission detector and the commercial detector above it. Detections are demonstrated at a range of operating conditions, including incoming particle type, count rate, and beam location on the detectors. The 13.5 μm detector is shown to work best to detect 2.7 MeV protons (H+), and the 8.5 μm detector is shown to work best to detect 5.4 MeV alpha particles (4He++). The development of a transmission detector enables a range of new experiments to take place at RARAF on radiation-stopping samples such as thick tissues, targets that need immersion microscopy, and integrated microfluidic devices for handling larger quantities of cells and small organisms. PMID:24058378

Urological applications of Raman spectroscopy for improved malignant diagnostics

Science.gov (United States)

Hart Prieto, M. Consuelo; Crow, Paul; Kendall, Catherine; Uff, Jeremy; Wright, Mark; Ritchie, Alistair; Stone, Nicholas

2004-07-01

The incidence of both prostate and bladder cancer is high; prostate cancer being the most frequently diagnosed non-cutaneous cancer affecting Western men. At present the gold standard for diagnosis of pathologies within the bladder and the prostate gland is by means of histological examination of biopsies. This is a subjective means of examining tissue and has an element of both inter and intra-observer variability. A large number of specimens have been collected and analysed using both a NIR-Raman spectrometer and histopathology with H&E staining. Multivariate spectral prediction models have been constructed and tested. An evaluation of misclassification cost models and the use of cancer staging data to train the models has been made.

Hand-held Raman sensor head for in-situ characterization of meat quality applying a microsystem 671 nm diode laser

Science.gov (United States)

Schmidt, Heinar; Sowoidnich, Kay; Maiwald, Martin; Sumpf, Bernd; Kronfeldt, Heinz-Detlef

2009-05-01

A hand-held Raman sensor head was developed for the in-situ characterization of meat quality. As light source, a microsystem based external cavity diode laser module (ECDL) emitting at 671 nm was integrated in the sensor head and attached to a miniaturized optical bench which contains lens optics for excitation and signal collection as well as a Raman filter stage for Rayleigh rejection. The signal is transported with an optical fiber to the detection unit which was in the initial phase a laboratory spectrometer with CCD detector. All elements of the ECDL are aligned on a micro optical bench with 13 x 4 mm2 footprint. The wavelength stability is provided by a reflection Bragg grating and the laser has an optical power of up to 200 mW. However, for the Raman measurements of meat only 35 mW are needed to obtain Raman spectra within 1 - 5 seconds. Short measuring times are essential for the hand-held device. The laser and the sensor head are characterized in terms of stability and performance for in-situ Raman investigations. The function is demonstrated in a series of measurements with raw and packaged pork meat as samples. The suitability of the Raman sensor head for the quality control of meat and other products will be discussed.

Synchrotron microbeam radiation therapy induces hypoxia in intracerebral gliosarcoma but not in the normal brain

International Nuclear Information System (INIS)

Bouchet, Audrey; Lemasson, Benjamin; Christen, Thomas; Potez, Marine; Rome, Claire; Coquery, Nicolas; Le Clec’h, Céline; Moisan, Anaick; Bräuer-Krisch, Elke; Leduc, Géraldine; Rémy, Chantal; Laissue, Jean A.; Barbier, Emmanuel L.; Brun, Emmanuel; Serduc, Raphaël

2013-01-01

Purpose: Synchrotron microbeam radiation therapy (MRT) is an innovative irradiation modality based on spatial fractionation of a high-dose X-ray beam into lattices of microbeams. The increase in lifespan of brain tumor-bearing rats is associated with vascular damage but the physiological consequences of MRT on blood vessels have not been described. In this manuscript, we evaluate the oxygenation changes induced by MRT in an intracerebral 9L gliosarcoma model. Methods: Tissue responses to MRT (two orthogonal arrays (2 × 400 Gy)) were studied using magnetic resonance-based measurements of local blood oxygen saturation (MR S O 2 ) and quantitative immunohistology of RECA-1, Type-IV collagen and GLUT-1, marker of hypoxia. Results: In tumors, MR S O 2 decreased by a factor of 2 in tumor between day 8 and day 45 after MRT. This correlated with tumor vascular remodeling, i.e. decrease in vessel density, increases in half-vessel distances (×5) and GLUT-1 immunoreactivity. Conversely, MRT did not change normal brain MR S O 2 , although vessel inter-distances increased slightly. Conclusion: We provide new evidence for the differential effect of MRT on tumor vasculature, an effect that leads to tumor hypoxia. As hypothesized formerly, the vasculature of the normal brain exposed to MRT remains sufficiently perfused to prevent any hypoxia

Monte Carlo-based treatment planning system calculation engine for microbeam radiation therapy.

Science.gov (United States)

Martinez-Rovira, I; Sempau, J; Prezado, Y

2012-05-01

Microbeam radiation therapy (MRT) is a synchrotron radiotherapy technique that explores the limits of the dose-volume effect. Preclinical studies have shown that MRT irradiations (arrays of 25-75-μm-wide microbeams spaced by 200-400 μm) are able to eradicate highly aggressive animal tumor models while healthy tissue is preserved. These promising results have provided the basis for the forthcoming clinical trials at the ID17 Biomedical Beamline of the European Synchrotron Radiation Facility (ESRF). The first step includes irradiation of pets (cats and dogs) as a milestone before treatment of human patients. Within this context, accurate dose calculations are required. The distinct features of both beam generation and irradiation geometry in MRT with respect to conventional techniques require the development of a specific MRT treatment planning system (TPS). In particular, a Monte Carlo (MC)-based calculation engine for the MRT TPS has been developed in this work. Experimental verification in heterogeneous phantoms and optimization of the computation time have also been performed. The penelope/penEasy MC code was used to compute dose distributions from a realistic beam source model. Experimental verification was carried out by means of radiochromic films placed within heterogeneous slab-phantoms. Once validation was completed, dose computations in a virtual model of a patient, reconstructed from computed tomography (CT) images, were performed. To this end, decoupling of the CT image voxel grid (a few cubic millimeter volume) to the dose bin grid, which has micrometer dimensions in the transversal direction of the microbeams, was performed. Optimization of the simulation parameters, the use of variance-reduction (VR) techniques, and other methods, such as the parallelization of the simulations, were applied in order to speed up the dose computation. Good agreement between MC simulations and experimental results was achieved, even at the interfaces between two

Monte Carlo-based treatment planning system calculation engine for microbeam radiation therapy

Energy Technology Data Exchange (ETDEWEB)

Martinez-Rovira, I.; Sempau, J.; Prezado, Y. [Institut de Tecniques Energetiques, Universitat Politecnica de Catalunya, Diagonal 647, Barcelona E-08028 (Spain) and ID17 Biomedical Beamline, European Synchrotron Radiation Facility (ESRF), 6 rue Jules Horowitz B.P. 220, F-38043 Grenoble Cedex (France); Institut de Tecniques Energetiques, Universitat Politecnica de Catalunya, Diagonal 647, Barcelona E-08028 (Spain); Laboratoire Imagerie et modelisation en neurobiologie et cancerologie, UMR8165, Centre National de la Recherche Scientifique (CNRS), Universites Paris 7 et Paris 11, Bat 440., 15 rue Georges Clemenceau, F-91406 Orsay Cedex (France)

2012-05-15

Purpose: Microbeam radiation therapy (MRT) is a synchrotron radiotherapy technique that explores the limits of the dose-volume effect. Preclinical studies have shown that MRT irradiations (arrays of 25-75-{mu}m-wide microbeams spaced by 200-400 {mu}m) are able to eradicate highly aggressive animal tumor models while healthy tissue is preserved. These promising results have provided the basis for the forthcoming clinical trials at the ID17 Biomedical Beamline of the European Synchrotron Radiation Facility (ESRF). The first step includes irradiation of pets (cats and dogs) as a milestone before treatment of human patients. Within this context, accurate dose calculations are required. The distinct features of both beam generation and irradiation geometry in MRT with respect to conventional techniques require the development of a specific MRT treatment planning system (TPS). In particular, a Monte Carlo (MC)-based calculation engine for the MRT TPS has been developed in this work. Experimental verification in heterogeneous phantoms and optimization of the computation time have also been performed. Methods: The penelope/penEasy MC code was used to compute dose distributions from a realistic beam source model. Experimental verification was carried out by means of radiochromic films placed within heterogeneous slab-phantoms. Once validation was completed, dose computations in a virtual model of a patient, reconstructed from computed tomography (CT) images, were performed. To this end, decoupling of the CT image voxel grid (a few cubic millimeter volume) to the dose bin grid, which has micrometer dimensions in the transversal direction of the microbeams, was performed. Optimization of the simulation parameters, the use of variance-reduction (VR) techniques, and other methods, such as the parallelization of the simulations, were applied in order to speed up the dose computation. Results: Good agreement between MC simulations and experimental results was achieved, even at

Correlation spectrometer

Science.gov (United States)

Sinclair, Michael B [Albuquerque, NM; Pfeifer, Kent B [Los Lunas, NM; Flemming, Jeb H [Albuquerque, NM; Jones, Gary D [Tijeras, NM; Tigges, Chris P [Albuquerque, NM

2010-04-13

A correlation spectrometer can detect a large number of gaseous compounds, or chemical species, with a species-specific mask wheel. In this mode, the spectrometer is optimized for the direct measurement of individual target compounds. Additionally, the spectrometer can measure the transmission spectrum from a given sample of gas. In this mode, infrared light is passed through a gas sample and the infrared transmission signature of the gasses present is recorded and measured using Hadamard encoding techniques. The spectrometer can detect the transmission or emission spectra in any system where multiple species are present in a generally known volume.

Estimating the concentration of urea and creatinine in the human serum of normal and dialysis patients through Raman spectroscopy.

Science.gov (United States)

de Almeida, Maurício Liberal; Saatkamp, Cassiano Junior; Fernandes, Adriana Barrinha; Pinheiro, Antonio Luiz Barbosa; Silveira, Landulfo

2016-09-01

Urea and creatinine are commonly used as biomarkers of renal function. Abnormal concentrations of these biomarkers are indicative of pathological processes such as renal failure. This study aimed to develop a model based on Raman spectroscopy to estimate the concentration values of urea and creatinine in human serum. Blood sera from 55 clinically normal subjects and 47 patients with chronic kidney disease undergoing dialysis were collected, and concentrations of urea and creatinine were determined by spectrophotometric methods. A Raman spectrum was obtained with a high-resolution dispersive Raman spectrometer (830 nm). A spectral model was developed based on partial least squares (PLS), where the concentrations of urea and creatinine were correlated with the Raman features. Principal components analysis (PCA) was used to discriminate dialysis patients from normal subjects. The PLS model showed r = 0.97 and r = 0.93 for urea and creatinine, respectively. The root mean square errors of cross-validation (RMSECV) for the model were 17.6 and 1.94 mg/dL, respectively. PCA showed high discrimination between dialysis and normality (95 % accuracy). The Raman technique was able to determine the concentrations with low error and to discriminate dialysis from normal subjects, consistent with a rapid and low-cost test.

Microbeam line of MeV heavy ions for materials modification and in-situ analysis

International Nuclear Information System (INIS)

Horino, Yuji; Chayahara, Akiyoshi; Kiuchi, Masato; Fujii, Kanenaga; Satoh, Mamoru; Takai, Mikio.

1990-01-01

A microbeam line for MeV heavy ions of almost any element has been developed for microion-beam processing such as maskless MeV ion implantation and its in-situ analysis. Beam spot sizes of 4.0 μm x 4.0 μm for 3 MeV C 2+ and 9.6 μm x 4.8 μm for 1.8 MeV Au 2+ beams were obtained. Maskless MeV gold ion implantation to a silicon substrate and in-situ microanalysis before and after ion implantation were demonstrated. (author)

Nucleolus degradation and growth induced by uv-microbeam irradiation of interphase cells grown in culture

International Nuclear Information System (INIS)

Sakharov, V.N.; Voronkova, N.

1976-01-01

In contrast to total cell irradiation, local UV-microbeam irradiation can stimulate a significant diminution in the irradiated mature nucleoli in interphase mammalian cells in culture. This diminution is accompanied by the concomitant expansion of the unirradiated nucleoli within the same nucleus, and the total nucleolar volume per nucleus does not change appreciably. It is suggested that these nucleolar volume changes are the result of the dispersion, migration, and redistribution of the nucleolar material between competitive nucleolar organizer regions of the interphase nucleus

PREFACE: EMAS 2013 Workshop: 13th European Workshop on Modern Developments and Applications in Microbeam Analysis

Science.gov (United States)

Llovet, Xavier, Dr; Matthews, Mr Michael B.; Brisset, François, Dr; Guimarães, Fernanda, Dr; Vieira, Professor Joaquim M., Dr

2014-03-01

This volume of the IOP Conference Series: Materials Science and Engineering contains papers from the 13th Workshop of the European Microbeam Analysis Society (EMAS) on Modern Developments and Applications in Microbeam Analysis which took place from the 12th to the 16th of May 2013 in the Centro de Congressos do Alfândega, Porto, Portugal. The primary aim of this series of workshops is to assess the state-of-the-art and reliability of microbeam analysis techniques. The workshops also provide a forum where students and young scientists starting out on a career in microbeam analysis can meet and discuss with the established experts. The workshops have a very specific format comprising invited plenary lectures by internationally recognized experts, poster presentations by the participants and round table discussions on the key topics led by specialists in the field. This workshop was organized in collaboration with LNEG - Laboratório Nacional de Energia e Geologia and SPMICROS - Sociedade Portuguesa de Microscopia. The technical programme included the following topics: electron probe microanalysis, future technologies, electron backscatter diffraction (EBSD), particle analysis, and applications. As at previous workshops there was also a special oral session for young scientists. The best presentation by a young scientist was awarded with an invitation to attend the 2014 Microscopy and Microanalysis meeting at Hartford, Connecticut. The prize went to Shirin Kaboli, of the Department of Metals and Materials Engineering of McGill University (Montréal, Canada), for her talk entitled ''Plastic deformation studies with electron channelling contrast imaging and electron backscattered diffraction''. The continuing relevance of the EMAS workshops and the high regard in which they are held internationally can be seen from the fact that 74 posters from 21 countries were on display at the meeting and that the participants came from as far away as Japan, Canada and the USA. A

Wavelength selection-based nonlinear calibration for transcutaneous blood glucose sensing using Raman spectroscopy

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Dingari, Narahara Chari; Barman, Ishan; Kang, Jeon Woong; Kong, Chae-Ryon; Dasari, Ramachandra R.; Feld, Michael S.

2011-01-01

While Raman spectroscopy provides a powerful tool for noninvasive and real time diagnostics of biological samples, its translation to the clinical setting has been impeded by the lack of robustness of spectroscopic calibration models and the size and cumbersome nature of conventional laboratory Raman systems. Linear multivariate calibration models employing full spectrum analysis are often misled by spurious correlations, such as system drift and covariations among constituents. In addition, such calibration schemes are prone to overfitting, especially in the presence of external interferences that may create nonlinearities in the spectra-concentration relationship. To address both of these issues we incorporate residue error plot-based wavelength selection and nonlinear support vector regression (SVR). Wavelength selection is used to eliminate uninformative regions of the spectrum, while SVR is used to model the curved effects such as those created by tissue turbidity and temperature fluctuations. Using glucose detection in tissue phantoms as a representative example, we show that even a substantial reduction in the number of wavelengths analyzed using SVR lead to calibration models of equivalent prediction accuracy as linear full spectrum analysis. Further, with clinical datasets obtained from human subject studies, we also demonstrate the prospective applicability of the selected wavelength subsets without sacrificing prediction accuracy, which has extensive implications for calibration maintenance and transfer. Additionally, such wavelength selection could substantially reduce the collection time of serial Raman acquisition systems. Given the reduced footprint of serial Raman systems in relation to conventional dispersive Raman spectrometers, we anticipate that the incorporation of wavelength selection in such hardware designs will enhance the possibility of miniaturized clinical systems for disease diagnosis in the near future. PMID:21895336

Interfacing an aspiration ion mobility spectrometer to a triple quadrupole mass spectrometer

International Nuclear Information System (INIS)

Adamov, Alexey; Viidanoja, Jyrki; Kaerpaenoja, Esko; Paakkanen, Heikki; Ketola, Raimo A.; Kostiainen, Risto; Sysoev, Alexey; Kotiaho, Tapio

2007-01-01

This article presents the combination of an aspiration-type ion mobility spectrometer with a mass spectrometer. The interface between the aspiration ion mobility spectrometer and the mass spectrometer was designed to allow for quick mounting of the aspiration ion mobility spectrometer onto a Sciex API-300 triple quadrupole mass spectrometer. The developed instrumentation is used for gathering fundamental information on aspiration ion mobility spectrometry. Performance of the instrument is demonstrated using 2,6-di-tert-butyl pyridine and dimethyl methylphosphonate

Analysis of low active-pharmaceutical-ingredient signal drugs based on thin layer chromatography and surface-enhanced Raman spectroscopy.

Science.gov (United States)

Li, Xiao; Chen, Hui; Zhu, Qingxia; Liu, Yan; Lu, Feng

2016-11-30

Active pharmaceutical ingredients (API) embedded in the excipients of the formula can usually be unravelled by normal Raman spectroscopy (NRS). However, more and more drugs with low API content and/or low Raman scattering coefficient were insensitive to NRS analysis, which was for the first time defined as Low API-Signal Drugs (LASIDs) in this paper. The NRS spectra of these LASIDs were similar to their dominant excipients' profiles, such as lactose, starch, microcrystalline cellulose (MCC), etc., and were classified into three types as such. 21 out of 100 kinds of drugs were screened as LASIDs and characterized further by Raman microscopic mapping. Accordingly, we proposed a tailored solution to the qualitation and quantitation problem of these LASIDs, using surface-enhanced Raman spectroscopic (SERS) detection on the thin layer chromatographic (TLC) plate both in situ and after-separation. Experimental conditions and parameters including TLC support matrix, SERS substrate, detection mode, similarity threshold, internal standard, etc., were optimized. All LASIDs were satisfactorily identified and the quantitation results agreed well with those of high performance liquid chromatography (HPLC). For some structural analogues of LASIDs, although they presented highly similar SERS spectra and were tough to distinguish even with Raman microscopic mapping, they could be successfully discriminated from each other by coupling SERS (with portable Raman spectrometer) with TLC. These results demonstrated that the proposed solution could be employed to detect the LASIDs with high accuracy and cost-effectiveness. Copyright © 2016 Elsevier B.V. All rights reserved.

The role of the micronucleus in stomatogenesis in sexual reproduction of Paramecium tetraurelia: laser microbeam irradiation of the micronucleus

International Nuclear Information System (INIS)

Tam Laiwa; Ng, S.F.

1986-01-01

Fifteen amicronucleate cell lines and 22 cell lines with defective micronuclei were obtained following selective laser microbeam irradiation of the micronucleus. The amicronucleate cell lines showed reduced growth rate and formed abnormal oral apparatuses in asexual reproduction, and failed to produce any oral apparatus in autogamy. The 22 cell lines with defective micronucleus exhibited various abnormalities of the oral apparatus newly formed during autogamy. These abnormalities included the arrest of membranelle assembly, reduction in the length of the buccal cavity and oral membranelles, disruption of the organization of the membranelles, quadrulation of the dorsal peniculus, and failure of addition of membranellar basal body rows. Hence the micronucleus plays multiple roles in sexual stomatogenesis. Our results agree with the notion that the micronucleus acts during a critical period between the second meiotic division and up to the formation of the zygotic nucleus to control the early stage of oral membranelle assembly. Laser microbeam irradiation might have created recessive mutations and/or chromosomal aberrations, which were expressed during this critical period with the formation of abnormal postmeiotic nuclei. (author)

Through tissue imaging of a live breast cancer tumour model using handheld surface enhanced spatially offset resonance Raman spectroscopy (SESORRS).

Science.gov (United States)

Nicolson, Fay; Jamieson, Lauren E; Mabbott, Samuel; Plakas, Konstantinos; Shand, Neil C; Detty, Michael R; Graham, Duncan; Faulds, Karen

2018-04-21

In order to improve patient survival and reduce the amount of unnecessary and traumatic biopsies, non-invasive detection of cancerous tumours is of imperative and urgent need. Multicellular tumour spheroids (MTS) can be used as an ex vivo cancer tumour model, to model in vivo nanoparticle (NP) uptake by the enhanced permeability and retention (EPR) effect. Surface enhanced spatially offset Raman spectroscopy (SESORS) combines both surface enhanced Raman spectroscopy (SERS) and spatially offset Raman spectroscopy (SORS) to yield enhanced Raman signals at much greater sub-surface levels. By utilizing a reporter that has an electronic transition in resonance with the laser frequency, surface enhanced resonance Raman scattering (SERRS) yields even greater enhancement in Raman signal. Using a handheld SORS spectrometer with back scattering optics, we demonstrate the detection of live breast cancer 3D MTS containing SERRS active NPs through 15 mm of porcine tissue. False color 2D heat intensity maps were used to determine tumour model location. In addition, we demonstrate the tracking of SERRS-active NPs through porcine tissue to depths of up to 25 mm. This unprecedented performance is due to the use of red-shifted chalcogenpyrylium-based Raman reporters to demonstrate the novel technique of surface enhanced spatially offset resonance Raman spectroscopy (SESORRS) for the first time. Our results demonstrate a significant step forward in the ability to detect vibrational fingerprints from a tumour model at depth through tissue. Such an approach offers significant promise for the translation of NPs into clinical applications for non-invasive disease diagnostics based on this new chemical principle of measurement.

Applications of high-throughput clonogenic survival assays in high-LET particle microbeams

Directory of Open Access Journals (Sweden)

Antonios eGeorgantzoglou

2016-01-01

Full Text Available Charged particle therapy is increasingly becoming a valuable tool in cancer treatment, mainly due to the favorable interaction of particle radiation with matter. Its application is still limited due, in part, to lack of data regarding the radiosensitivity of certain cell lines to this radiation type, especially to high-LET particles. From the earliest days of radiation biology, the clonogenic survival assay has been used to provide radiation response data. This method produces reliable data but it is not optimized for high-throughput microbeam studies with high-LET radiation where high levels of cell killing lead to a very low probability of maintaining cells’ clonogenic potential. A new method, therefore, is proposed in this paper, which could potentially allow these experiments to be conducted in a high-throughput fashion. Cells are seeded in special polypropylene dishes and bright-field illumination provides cell visualization. Digital images are obtained and cell detection is applied based on corner detection, generating individual cell targets as x-y points. These points in the dish are then irradiated individually by a micron field size high-LET microbeam. Post-irradiation, time-lapse imaging follows cells’ response. All irradiated cells are tracked by linking trajectories in all time-frames, based on finding their nearest position. Cell divisions are detected based on cell appearance and individual cell temporary corner density. The number of divisions anticipated is low due to the high probability of cell killing from high-LET irradiation. Survival curves are produced based on cell’s capacity to divide at least 4-5 times. The process is repeated for a range of doses of radiation. Validation shows the efficiency of the proposed cell detection and tracking method in finding cell divisions.

Applications of High-Throughput Clonogenic Survival Assays in High-LET Particle Microbeams.

Science.gov (United States)

Georgantzoglou, Antonios; Merchant, Michael J; Jeynes, Jonathan C G; Mayhead, Natalie; Punia, Natasha; Butler, Rachel E; Jena, Rajesh

2015-01-01

Charged particle therapy is increasingly becoming a valuable tool in cancer treatment, mainly due to the favorable interaction of particle radiation with matter. Its application is still limited due, in part, to lack of data regarding the radiosensitivity of certain cell lines to this radiation type, especially to high-linear energy transfer (LET) particles. From the earliest days of radiation biology, the clonogenic survival assay has been used to provide radiation response data. This method produces reliable data but it is not optimized for high-throughput microbeam studies with high-LET radiation where high levels of cell killing lead to a very low probability of maintaining cells' clonogenic potential. A new method, therefore, is proposed in this paper, which could potentially allow these experiments to be conducted in a high-throughput fashion. Cells are seeded in special polypropylene dishes and bright-field illumination provides cell visualization. Digital images are obtained and cell detection is applied based on corner detection, generating individual cell targets as x-y points. These points in the dish are then irradiated individually by a micron field size high-LET microbeam. Post-irradiation, time-lapse imaging follows cells' response. All irradiated cells are tracked by linking trajectories in all time-frames, based on finding their nearest position. Cell divisions are detected based on cell appearance and individual cell temporary corner density. The number of divisions anticipated is low due to the high probability of cell killing from high-LET irradiation. Survival curves are produced based on cell's capacity to divide at least four to five times. The process is repeated for a range of doses of radiation. Validation shows the efficiency of the proposed cell detection and tracking method in finding cell divisions.

Surface-enhanced Raman spectroscopy based on conical holed enhancing substrates

International Nuclear Information System (INIS)

Chen, Yao; Chen, Zeng-Ping; Zuo, Qi; Shi, Cai-Xia; Yu, Ru-Qin

2015-01-01

In this contribution, surface-enhanced Raman spectroscopy (SERS) based on conical holed glass substrates deposited with silver colloids was reported for the first time. It combines the advantages of both dry SERS assays based on plane films deposited with silver colloids and wet SERS assays utilizing cuvettes or capillary tubes. Compared with plane glass substrates deposited with silver colloids, the conical holed glass substrates deposited with silver colloids exhibited five-to ten-folds of increase in the rate of signal enhancement, due to the internal multiple reflections of both the excitation laser beam and the Raman scattering photons within conical holes. The application of conical holed glass substrates could also yield significantly stronger and more reproducible SERS signals than SERS assays utilizing capillary tubes to sample the mixture of silver colloids and the solution of the analyte of interest. The conical holed glass substrates in combination with the multiplicative effects model for surface-enhanced Raman spectroscopy (MEM SERS ) achieved quite sensitive and precise quantification of 6-mercaptopurine in complex plasma samples with an average relative prediction error of about 4% and a limit of detection of about 0.02 μM using a portable i-Raman 785H spectrometer. It is reasonable to expect that SERS technique based on conical holed enhancing substrates in combination with MEM SERS model can be developed and extended to other application areas such as drug detection, environmental monitoring, and clinic analysis, etc. - Highlights: • A novel conical holed SERS enhancing substrate was designed and manufactured. • The optimal conical holed glass substrates can produce stronger SERS signal. • The novel substrates can overcome the shortcomings of both dry and wet methods. • The novel substrates coupled with MEM SERS can realize quantitative SERS assays

Resonant X-ray Raman scattering for Al, Si and their oxides

International Nuclear Information System (INIS)

Szlachetko, J.; Berset, M.; Dousse, J.-Cl.; Fennane, K.; Szlachetko, M.; Barrett, R.; Hoszowska, J.; Kubala-Kukus, A.; Pajek, M.

2005-01-01

High-resolution measurements of the resonant X-ray Raman scattering (RRS) of Al and Si and their oxides were performed at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France, using a von Hamos Bragg-type curved crystal spectrometer. To probe the influence of chemical effects on the RRS X-ray spectra, Al 2 O 3 and SiO 2 samples were also investigated. The X-ray RRS spectra were measured at different photon beam energies tuned below the K-absorption edge. The measured spectra are compared to results of RRS calculations based on the second-order perturbation theory within the Kramers-Heisenberg approach

Discriminating model for diagnosis of basal cell carcinoma and melanoma in vitro based on the Raman spectra of selected biochemicals

Science.gov (United States)

Silveira, Landulfo; Silveira, Fabrício Luiz; Bodanese, Benito; Zângaro, Renato Amaro; Pacheco, Marcos Tadeu T.

2012-07-01

Raman spectroscopy has been employed to identify differences in the biochemical constitution of malignant [basal cell carcinoma (BCC) and melanoma (MEL)] cells compared to normal skin tissues, with the goal of skin cancer diagnosis. We collected Raman spectra from compounds such as proteins, lipids, and nucleic acids, which are expected to be represented in human skin spectra, and developed a linear least-squares fitting model to estimate the contributions of these compounds to the tissue spectra. We used a set of 145 spectra from biopsy fragments of normal (30 spectra), BCC (96 spectra), and MEL (19 spectra) skin tissues, collected using a near-infrared Raman spectrometer (830 nm, 50 to 200 mW, and 20 s exposure time) coupled to a Raman probe. We applied the best-fitting model to the spectra of biochemicals and tissues, hypothesizing that the relative spectral contribution of each compound to the tissue Raman spectrum changes according to the disease. We verified that actin, collagen, elastin, and triolein were the most important biochemicals representing the spectral features of skin tissues. A classification model applied to the relative contribution of collagen III, elastin, and melanin using Euclidean distance as a discriminator could differentiate normal from BCC and MEL.

Sub-millisecond time-resolved SAXS using a continuous-flow mixer and X-ray microbeam.

Science.gov (United States)

Graceffa, Rita; Nobrega, R Paul; Barrea, Raul A; Kathuria, Sagar V; Chakravarthy, Srinivas; Bilsel, Osman; Irving, Thomas C

2013-11-01

Small-angle X-ray scattering (SAXS) is a well established technique to probe the nanoscale structure and interactions in soft matter. It allows one to study the structure of native particles in near physiological environments and to analyze structural changes in response to variations in external conditions. The combination of microfluidics and SAXS provides a powerful tool to investigate dynamic processes on a molecular level with sub-millisecond time resolution. Reaction kinetics in the sub-millisecond time range has been achieved using continuous-flow mixers manufactured using micromachining techniques. The time resolution of these devices has previously been limited, in part, by the X-ray beam sizes delivered by typical SAXS beamlines. These limitations can be overcome using optics to focus X-rays to the micrometer size range providing that beam divergence and photon flux suitable for performing SAXS experiments can be maintained. Such micro-SAXS in combination with microfluidic devices would be an attractive probe for time-resolved studies. Here, the development of a high-duty-cycle scanning microsecond-time-resolution SAXS capability, built around the Kirkpatrick-Baez mirror-based microbeam system at the Biophysics Collaborative Access Team (BioCAT) beamline 18ID at the Advanced Photon Source, Argonne National Laboratory, is reported. A detailed description of the microbeam small-angle-scattering instrument, the turbulent flow mixer, as well as the data acquisition and control and analysis software is provided. Results are presented where this apparatus was used to study the folding of cytochrome c. Future prospects for this technique are discussed.

Analysis of metallic pigments by ion microbeam

International Nuclear Information System (INIS)

Pelicon, P.; Klanjsek-Gunde, M.; Kunaver, M.; Simcic, J.; Budnar, M.

2002-01-01

Metallic paints consist of metallic flakes dispersed in a resinous binder, i.e. a light-element polymer matrix. The spatial distribution and orientation of metallic flakes inside the matrix determines the covering efficiency of the paint, glossiness, and its angular-dependent properties such as lightness flop or color flop (two-tone). Such coatings are extensively used for a functional (i.e. security) as well as decorative purpose. The ion microbeam analysis of two types of silver paint with imbedded metallic flakes has been performed to determine the spatial distribution of the aluminum flakes in paint layer. The average sizes of the aluminum flakes were 23 μm (size distribution 10-37) and 49 μm (size distribution 34-75), respectively. The proton beam with the size of 2x2 μm 2 at Ljubljana ion microprobe has been used to scan the surface of the pigments. PIXE mapping of Al Kα map shows lateral distribution of the aluminum flakes, whereas the RBS slicing method reveals tomograms of the flakes in uppermost 7 μm of the pigment layer. The series of point analysis aligned over the single flake reveal the flake angle in respect to the polymer matrix surface. The angular sensitivity is well below 1 angular degree

Detecting adulterants in milk with lower cost mid-infrared and Raman spectroscopy

Science.gov (United States)

Lee, Changwon; Wang, Wenbo; Wilson, Benjamin K.; Connett, Marie; Keller, Matthew D.

2018-02-01

Adulteration of milk for economic gains is a widespread issue throughout the developing world that can have far-reaching health and nutritional impacts. Milk analysis technologies, such as infrared spectroscopy, can screen for adulteration, but the cost of these technologies has prohibited their use in low resource settings. Recent developments in infrared and Raman spectroscopy hardware have led to commercially available low-cost devices. In this work, we evaluated the performance of two such spectrometers in detecting and quantifying the presence of milk adulterants. Five common adulterants - ammonium sulfate, melamine, sodium bicarbonate, sucrose, and urea, were spiked into five different raw cow and goat milk samples at different concentrations. Collected MIR and Raman spectra were analyzed using partial least squares regression. The limit of detection (LOD) for each adulterant was determined to be in the range of 0.04 to 0.28% (400 to 2800 ppm) using MIR spectroscopy. Raman spectroscopy showed similar LOD's for some of the adulterants, notably those with strong amine group signals, and slightly higher LOD's (up to 1.0%) for other molecules. Overall, the LODs were comparable to other spectroscopic milk analyzers on the market, and they were within the economically relevant concentration range of 100 to 4000 ppm. These lower cost spectroscopic devices therefore appear to hold promise for use in low resource settings.

Lichen biomarkers upon heating: a Raman spectroscopic study with implications for extra-terrestrial exploration

Science.gov (United States)

Miralles, I.; Capel Ferrón, C.; Hernández, V.; López-Navarrete, J. T.; Jorge-Villar, S. E.

2017-01-01

Lithopanspermia Theory has suggested that life was transferred among planets by meteorites and other rocky bodies. If the planet had an atmosphere, this transfer of life had to survive drastic temperature changes in a very short time in its entry or exit. Only organisms able to endure such a temperature range could colonize a planet from outer space. Many experiments are being carried out by NASA and European Space Agency to understand which organisms were able to survive and how. Among the suite of instruments designed for extraplanetary exploration, particularly for Mars surface exploration, a Raman spectrometer was selected with the main objective of looking for life signals. Among all attributes, Raman spectroscopy is able to identify organic and inorganic compounds, either pure or in admixture, without requiring sample manipulation. In this study, we used Raman spectroscopy to examine the lichen Squamarina lentigera biomarkers. We analyse spectral signature changes after sample heating under different experimental situations, such as (a) laser, (b) analysis accumulations over the same spot and (c) environmental temperature increase. Our goal is to evaluate the capability of Raman spectroscopy to identify unambiguously life markers even if heating has induced spectral changes, reflecting biomolecular transformations. Usnic acid, chlorophyll, carotene and calcium oxalates were identified by the Raman spectra. From our experiments, we have seen that usnic acid, carotene and calcium oxalates (the last two have been suggested to be good biomarkers) respond in a different way to environmental heating. Our main conclusion is that despite their abundance in nature or their inorganic composition the resistance to heat makes some molecules more suitable than others as biomarkers.

Monolithic spectrometer

Energy Technology Data Exchange (ETDEWEB)

Rajic, Slobodan (Knoxville, TN); Egert, Charles M. (Oak Ridge, TN); Kahl, William K. (Knoxville, TN); Snyder, Jr., William B. (Knoxville, TN); Evans, III, Boyd M. (Oak Ridge, TN); Marlar, Troy A. (Knoxville, TN); Cunningham, Joseph P. (Oak Ridge, TN)

1998-01-01

A monolithic spectrometer is disclosed for use in spectroscopy. The spectrometer is a single body of translucent material with positioned surfaces for the transmission, reflection and spectral analysis of light rays.

A method of dosimetry for synchrotron microbeam radiation therapy using radiochromic films and microdensitometry

International Nuclear Information System (INIS)

Crosbie, J. C.; Svalbe, I. D.; Lewis, R. A.

2007-01-01

Full text: Normal tissue displays an exceptional tolerance to high doses of radiation (hundreds of Gy) when delivered as a microplanar array of synchrotron-generated x-rays. Furthermore, MRT has been shown to cause significant tumour growth delay and in some case complete ablation. The biological effects of MRT on tissue are not fully understood. This is further complicated by difficulties in performing accurate dosimetry. The majority of dosimetry performed for MRT has been Monte Carlo simulations. The aim of this work was to utilise film dosimetry and microdensitometry to measure the peak-to-valley dose ratios (PVDRs) for synchrotron microbeam radiation therapy.

Micro-CT of sea urchin ossicles supplemented with microbeam diffraction

Science.gov (United States)

Stock, Stuart R.; Ignatiev, Konstantin I.; Veis, Arthur; De Carlo, Francesco; Almer, J. D.

2004-10-01

Sea urchins employ as wide a range of composite reinforcement strategies as are seen in engineering composites. Besides tailoring reinforcement morphology and alignment to the functional demands of position, solid solution strengthening (high Mg calcite), inclusion toughening (macromolecules), functional gradients in mineral reinforcement morphology, composition and dimensions and mineral interface tailoring are other tactics important to achieving high toughness and high strength in sea urchin teeth. Teeth from different echinoid families illustrate combinations of reinforcement parameters and toughening mechanisms providing good functionality, a virtual probe of the available design space. This paper focuses on a multi-mode x-ray investigation of sea urchin teeth studied on scales approaching 1 μm in millimeter-sized samples, in particular mapping 3-D microarchitecture with synchrotron and laboratory microCT and mapping Ca1-xMgxCO3 crystal composition x and microstrain and crystallite size via microbeam diffraction.

Assessing the Temperature Dependence of Narrow-Band Raman Water Vapor Lidar Measurements: A Practical Approach

Science.gov (United States)

Whiteman, David N.; Venable, Demetrius D.; Walker, Monique; Cardirola, Martin; Sakai, Tetsu; Veselovskii, Igor

2013-01-01

Narrow-band detection of the Raman water vapor spectrum using the lidar technique introduces a concern over the temperature dependence of the Raman spectrum. Various groups have addressed this issue either by trying to minimize the temperature dependence to the point where it can be ignored or by correcting for whatever degree of temperature dependence exists. The traditional technique for performing either of these entails accurately measuring both the laser output wavelength and the water vapor spectral passband with combined uncertainty of approximately 0.01 nm. However, uncertainty in interference filter center wavelengths and laser output wavelengths can be this large or larger. These combined uncertainties translate into uncertainties in the magnitude of the temperature dependence of the Raman lidar water vapor measurement of 3% or more. We present here an alternate approach for accurately determining the temperature dependence of the Raman lidar water vapor measurement. This alternate approach entails acquiring sequential atmospheric profiles using the lidar while scanning the channel passband across portions of the Raman water vapor Q-branch. This scanning is accomplished either by tilt-tuning an interference filter or by scanning the output of a spectrometer. Through this process a peak in the transmitted intensity can be discerned in a manner that defines the spectral location of the channel passband with respect to the laser output wavelength to much higher accuracy than that achieved with standard laboratory techniques. Given the peak of the water vapor signal intensity curve, determined using the techniques described here, and an approximate knowledge of atmospheric temperature, the temperature dependence of a given Raman lidar profile can be determined with accuracy of 0.5% or better. A Mathematica notebook that demonstrates the calculations used here is available from the lead author.

Microbeam facility extension for single-cell irradiation experiments. Investigations about bystander effect and reactive oxygen species impact

International Nuclear Information System (INIS)

Hanot, M.; Khodja, H.; Daudin, L.; Hoarau, J.; Carriere, M.; Gouget, B.

2006-01-01

The LPS microbeam facility is based on a KN3750 Van de Graaff accelerator devoted to microbeam analysis [1]. It is equipped with two horizontal microbeam lines used in various fields such as material science, geological science, nuclear material science and biology. Since two years, a single ion hit device is being developed at the LPS. The setup is dedicated to the study of ionizing radiation effects on living cells by performing single ion irradiation at controlled doses and locations. This study will complete current researches conducted on uranium chemical toxicity on renal an d osteoblastic cells. After ingestion, most uranium is excreted from the body within a few days except small fraction that is absorbed into the blood-stream (0.2 to 5%) and then deposit and preferentially in kidneys and bones, where it can remain for many years. Uranium is a heavy metal and a primarily alpha emitter. It can lead to bone cancer as a result of the ionizing radiation associated with the radioactive decay products. The study of the response to an exposure to alpha particles will permit to distinguish radiotoxicity and chemical toxicity of uranium bone cells with a special emphasis or the bystander effect at low dose.All the beam lines at the LPS nuclear microprobe are horizontal and under vacuum. A dedicated deflecting magnet was inserted in one of the two available beam lines of the facility. The ion beam is extracted to air using a 100 nm thick silicon nitride membrane, thin enough to induce negligible effects on the ions in terms of energy loss and spatial resolution. By this way, we believe that we minimize the experimental setup impact on the living cells easing the detection of low irradiation dose impact. The atmosphere around the samples is also important to guaranty low stressed cell culture conditions. A temperature, hygrometry and CO 2 controlled atmosphere device will be implanted in the future. The irradiation microbeam is produced using a fused silica capillary

High-precision radiosurgical dose delivery by interlaced microbeam arrays of high-flux low-energy synchrotron X-rays.

Directory of Open Access Journals (Sweden)

Raphaël Serduc

Full Text Available Microbeam Radiation Therapy (MRT is a preclinical form of radiosurgery dedicated to brain tumor treatment. It uses micrometer-wide synchrotron-generated X-ray beams on the basis of spatial beam fractionation. Due to the radioresistance of normal brain vasculature to MRT, a continuous blood supply can be maintained which would in part explain the surprising tolerance of normal tissues to very high radiation doses (hundreds of Gy. Based on this well described normal tissue sparing effect of microplanar beams, we developed a new irradiation geometry which allows the delivery of a high uniform dose deposition at a given brain target whereas surrounding normal tissues are irradiated by well tolerated parallel microbeams only. Normal rat brains were exposed to 4 focally interlaced arrays of 10 microplanar beams (52 microm wide, spaced 200 microm on-center, 50 to 350 keV in energy range, targeted from 4 different ports, with a peak entrance dose of 200Gy each, to deliver an homogenous dose to a target volume of 7 mm(3 in the caudate nucleus. Magnetic resonance imaging follow-up of rats showed a highly localized increase in blood vessel permeability, starting 1 week after irradiation. Contrast agent diffusion was confined to the target volume and was still observed 1 month after irradiation, along with histopathological changes, including damaged blood vessels. No changes in vessel permeability were detected in the normal brain tissue surrounding the target. The interlacing radiation-induced reduction of spontaneous seizures of epileptic rats illustrated the potential pre-clinical applications of this new irradiation geometry. Finally, Monte Carlo simulations performed on a human-sized head phantom suggested that synchrotron photons can be used for human radiosurgical applications. Our data show that interlaced microbeam irradiation allows a high homogeneous dose deposition in a brain target and leads to a confined tissue necrosis while sparing

Preliminary investigation of an atmospheric microplasma using Raman and Thomson laser scattering

Science.gov (United States)

Sommers, Bradley; Adams, Steven

2014-10-01

A triple grating spectrometer system has been coupled with an ultraviolet laser at 266 nm for the purpose of investigating Rayleigh, Raman, and Thomson scattering within atmospheric plasma sources. Such laser interactions present a non-invasive diagnostic to investigate small scale atmospheric plasma sources, which have recently garnered interest for applications in remote optical sensing, materials processing, and environmental decontamination. In this work, the laser scatter and temperature relationship were calibrated with a heated nitrogen cell held at atmospheric pressure while subsequent scattering measurements were made in atmospheric discharges composed of nitrogen and air. An adjustable electrode configuration and dc circuit were assembled to produce a microdischarge operating in normal glow mode, thus providing a non-thermal plasma in which the translational, rotational, vibrational and electron temperatures are not in equilibrium. Preliminary results include measurements of these temperatures, which were calculated by fitting simulated scattering spectra to the experimental data obtained using the triple grating spectrometer. Measured temperatures were also compared with those obtained using standard optical emission spectroscopy methods. Special thanks to the NRC Research Associateship Program.

Real-time biochemical sensor based on Raman scattering with CMOS contact imaging.

Science.gov (United States)

Muyun Cao; Yuhua Li; Yadid-Pecht, Orly

2015-08-01

This work presents a biochemical sensor based on Raman scattering with Complementary metal-oxide-semiconductor (CMOS) contact imaging. This biochemical optical sensor is designed for detecting the concentration of solutions. The system is built with a laser diode, an optical filter, a sample holder and a commercial CMOS sensor. The output of the system is analyzed by an image processing program. The system provides instant measurements with a resolution of 0.2 to 0.4 Mol. This low cost and easy-operated small scale system is useful in chemical, biomedical and environmental labs for quantitative bio-chemical concentration detection with results reported comparable to a highly cost commercial spectrometer.

Multi-mode optical fibers for connecting space-based spectrometers

Science.gov (United States)

Roberts, W. T.; Lindenmisth, C. A.; Bender, S.; Miller, E. A.; Motts, E.; Ott, M.; LaRocca, F.; Thomes, J.

2017-11-01

Laser spectral analysis systems are increasingly being considered for in situ analysis of the atomic and molecular composition of selected rock and soil samples on other planets [1][2][3]. Both Laser Induced Breakdown Spectroscopy (LIBS) and Raman spectroscopy are used to identify the constituents of soil and rock samples in situ. LIBS instruments use a high peak-power laser to ablate a minute area of the surface of a sample. The resulting plasma is observed with an optical head, which collects the emitted light for analysis by one or more spectrometers. By identifying the ion emission lines observed in the plasma, the constituent elements and their abundance can be deduced. In Raman spectroscopy, laser photons incident on the sample surface are scattered and experience a Raman shift, exchanging small amounts of energy with the molecules scattering the light. By observing the spectrum of the scattered light, it is possible to determine the molecular composition of the sample. For both types of instruments, there are advantages to physically separating the light collecting optics from the spectroscopy optics. The light collection system will often have articulating or rotating elements to facilitate the interrogation of multiple samples with minimum expenditure of energy and motion. As such, the optical head is often placed on a boom or an appendage allowing it to be pointed in different directions or easily positioned in different locations. By contrast, the spectrometry portion of the instrument is often well-served by placing it in a more static location. The detectors often operate more consistently in a thermally-controlled environment. Placing them deep within the spacecraft structure also provides some shielding from ionizing radiation, extending the instrument's useful life. Finally, the spectrometry portion of the instrument often contains significant mass, such that keeping it off of the moving portion of the platform, allowing that portion to be

Development and characterization of a handheld hyperspectral Raman imaging probe system for molecular characterization of tissue on mesoscopic scales.

Science.gov (United States)

St-Arnaud, Karl; Aubertin, Kelly; Strupler, Mathias; Madore, Wendy-Julie; Grosset, Andrée-Anne; Petrecca, Kevin; Trudel, Dominique; Leblond, Frédéric

2018-01-01

Raman spectroscopy is a promising cancer detection technique for surgical guidance applications. It can provide quantitative information relating to global tissue properties associated with structural, metabolic, immunological, and genetic biochemical phenomena in terms of molecular species including amino acids, lipids, proteins, and nucleic acid (DNA). To date in vivo Raman spectroscopy systems mostly included probes and biopsy needles typically limited to single-point tissue interrogation over a scale between 100 and 500 microns. The development of wider field handheld systems could improve tumor localization for a range of open surgery applications including brain, ovarian, and skin cancers. Here we present a novel Raman spectroscopy implementation using a coherent imaging bundle of fibers to create a probe capable of reconstructing molecular images over mesoscopic fields of view. Detection is performed using linear scanning with a rotation mirror and an imaging spectrometer. Different slits widths were tested at the entrance of the spectrometer to optimize spatial and spectral resolution while preserving sufficient signal-to-noise ratios to detect the principal Raman tissue features. The nonbiological samples, calcite and polytetrafluoroethylene (PTFE), were used to characterize the performance of the system. The new wide-field probe was tested on ex vivo samples of calf brain and swine tissue. Raman spectral content of both tissue types were validated with data from the literature and compared with data acquired with a single-point Raman spectroscopy probe. The single-point probe was used as the gold standard against which the new instrument was benchmarked as it has already been thoroughly validated for biological tissue characterization. We have developed and characterized a practical noncontact handheld Raman imager providing tissue information at a spatial resolution of 115 microns over a field of view >14 mm 2 and a spectral resolution of 6 cm -1 over

Development of in situ time-resolved Raman spectroscopy facility for dynamic shock loading in materials

Science.gov (United States)

Chaurasia, S.; Rastogi, V.; Rao, U.; Sijoy, C. D.; Mishra, V.; Deo, M. N.

2017-11-01

The transient state of excitation and relaxation processes in materials under shock compression can be investigated by coupling the laser driven shock facility with Raman spectroscopy. For this purpose, a time resolved Raman spectroscopy setup has been developed to monitor the physical and the chemical changes such as phase transitions, chemical reactions, molecular kinetics etc., under shock compression with nanosecond time resolution. This system consist of mainly three parts, a 2 J/8 ns Nd:YAG laser system used for generation of pump and probe beams, a Raman spectrometer with temporal and spectral resolution of 1.2 ns and 3 cm-1 respectively and a target holder in confinement geometry assembly. Detailed simulation for the optimization of confinement geometry targets is performed. Time resolved measurement of polytetrafluoroethylene (PTFE) targets at focused laser intensity of 2.2 GW/cm2 has been done. The corresponding pressure in the Aluminum and PTFE are 3.6 and 1.7 GPa respectively. At 1.7 GPa in PTFE, a red shift of 5 cm-1 is observed for the CF2 twisting mode (291 cm-1). Shock velocity in PTFE is calculated by measuring rate of change of ratios of the intensity of Raman lines scattered from shocked volume to total volume of sample in the laser focal spot along the laser axis. The calculated shock velocity in PTFE is found to be 1.64 ± 0.16 km/s at shock pressure of 1.7 GPa, for present experimental conditions.

Monte Carlo study of the influence of energy spectra, mesh size, high Z element on dose and PVDR based on 1-D and 3-D heterogeneous mouse head phantom for Microbeam Radiation Therapy.

Science.gov (United States)

Lin, Hui; Jing, Jia; Xu, Liangfeng; Mao, Xiaoli

2017-12-01

To evaluate the influence of energy spectra, mesh sizes, high Z element on dose and PVDR in Microbeam Radiation Therapy (MRT) based on 1-D analogy-mouse-head-model (1-D MHM) and 3-D voxel-mouse-head-phantom (3-D VMHP) by Monte Carlo simulation. A Microbeam-Array-Source-Model was implemented into EGSnrc/DOSXYZnrc. The microbeam size is assumed to be 25μm, 50μm or 75μm in thickness and fixed 1mm in height with 200μmc-t-c. The influence of the energy spectra of ID17@ESRF and BMIT@CLS were investigated. The mesh size was optimized. PVDR in 1-D MHM and 3-D VMHP was compared with the homogeneous water phantom. The arc influence of 3-D VMHP filled with water (3-D VMHWP) was compared with the rectangle phantom. PVDR of the lower BMIT@CLS spectrum is 2.4times that of ID17@ESRF for lower valley dose. The optimized mesh is 5µm for 25µm, and 10µm for 50µm and 75µm microbeams with 200µmc-t-c. A 500μm skull layer could make PVDR difference up to 62.5% for 1-D MHM. However this influence is limited (influence is limited for the more depth (influence of 3-D heterogeneous media. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Combined laser ultrasonics, laser heating, and Raman scattering in diamond anvil cell system

Science.gov (United States)

Zinin, Pavel V.; Prakapenka, Vitali B.; Burgess, Katherine; Odake, Shoko; Chigarev, Nikolay; Sharma, Shiv K.

2016-12-01

We developed a multi-functional in situ measurement system under high pressure equipped with a laser ultrasonics (LU) system, Raman device, and laser heating system (LU-LH) in a diamond anvil cell (DAC). The system consists of four components: (1) a LU-DAC system (probe and pump lasers, photodetector, and oscilloscope) and DAC; (2) a fiber laser, which is designed to allow precise control of the total power in the range from 2 to 100 W by changing the diode current, for heating samples; (3) a spectrometer for measuring the temperature of the sample (using black body radiation), fluorescence spectrum (spectrum of the ruby for pressure measurement), and Raman scattering measurements inside a DAC under high pressure and high temperature (HPHT) conditions; and (4) an optical system to focus laser beams on the sample and image it in the DAC. The system is unique and allows us to do the following: (a) measure the shear and longitudinal velocities of non-transparent materials under HPHT; (b) measure temperature in a DAC under HPHT conditions using Planck's law; (c) measure pressure in a DAC using a Raman signal; and (d) measure acoustical properties of small flat specimens removed from the DAC after HPHT treatment. In this report, we demonstrate that the LU-LH-DAC system allows measurements of velocities of the skimming waves in iron at 2580 K and 22 GPa.

Complete synchronization condition in a network of piezoelectric micro-beam

International Nuclear Information System (INIS)

Taffoti Yolong, V.Y.; Woafo, P.

2007-10-01

This work deals with the dynamics of a network of piezoelectric micro-beams. The complete synchronization condition for this class of chaotic nonlinear electromechanical systems devices with nearest-neighbor diffusive coupling is studied. The nonlinearities on the device studied here are both on the electrical component and on the mechanical one. The investigation is made for the case of a large number of discrete piezoelectric disks coupled. The problem of chaos synchronization is described and converted into the analysis of stability of the system via its differential equations. We show that the complete synchronization of N identical coupled nonlinear chaotic systems having the shift invariant coupling schemes can be calculated from the synchronization of two of them coupled in both directions. According to analytical, semi-analytical predictions and numerical calculations, the transition boundaries for chaos synchronization state in the coupled system are determined as a function of the increasing number of oscillators. (author)

Piezoelectric transduction of flexural modes in pre-stressed microbeam resonators

Science.gov (United States)

Torri, G. B.; Janssen, N. M. A.; Zeng, Z.; Rottenberg, X.; Karabacak, D. M.; Vandecasteele, M.; Van Hoof, C.; Puers, R.; Tilmans, H. A. C.

2014-08-01

This paper reports on the optimization of the design of piezoelectric transducer elements integrated on doubly-clamped microbeam resonators utilized as (bio)chemical sensors. We report and emphasize the often forgotten influence of membrane stresses on defining the dimensions and optimal position of the piezoelectric transducer elements. The study takes into account stress induced structural changes and provides models for the equivalent motional parameters of resonators with particular shapes of the transducers matching the flexural modes of vibration. The above is analyzed theoretically using numerical models and is confirmed by impedance measurements and optical measurements of fabricated doubly-clamped beam resonators. We propose various transducer designs and highlight the advantages of using higher order vibration modes by implementing specially designed mode matching transducer elements. It is concluded that the paper describes and highlights the importance of accounting for the membrane stresses to optimize the resonator performance and the low power in electronic feedback of resonating sensing systems.

Piezoelectric transduction of flexural modes in pre-stressed microbeam resonators

International Nuclear Information System (INIS)

Torri, G B; Rottenberg, X; Hoof, C Van; Puers, R; Tilmans, H A C; Janssen, N M A; Zeng, Z; Karabacak, D M; Vandecasteele, M

2014-01-01

This paper reports on the optimization of the design of piezoelectric transducer elements integrated on doubly-clamped microbeam resonators utilized as (bio)chemical sensors. We report and emphasize the often forgotten influence of membrane stresses on defining the dimensions and optimal position of the piezoelectric transducer elements. The study takes into account stress induced structural changes and provides models for the equivalent motional parameters of resonators with particular shapes of the transducers matching the flexural modes of vibration. The above is analyzed theoretically using numerical models and is confirmed by impedance measurements and optical measurements of fabricated doubly-clamped beam resonators. We propose various transducer designs and highlight the advantages of using higher order vibration modes by implementing specially designed mode matching transducer elements. It is concluded that the paper describes and highlights the importance of accounting for the membrane stresses to optimize the resonator performance and the low power in electronic feedback of resonating sensing systems. (paper)

Determination of ripeness stages of Mazafati variety of date fruit by Raman spectroscopy

Directory of Open Access Journals (Sweden)

R Khodabakhshian

2016-04-01

study was to evaluate the feasibility of a nondestructive method based on FT-Raman spectroscopy in distinction of Mazafati date fruits according to four mentioned ripeness stages. Materials and Methods: Sample preparation: Mazafati variety of date fruit was used for this study. During the harvest seasons of 2012 (July-August, the samples from each four stages of ripening namely Kimri, Khalal, Rutab and Tamr were collected from two different orchards in Bam, Kerman province, Iran. A number of 100 date samples were tested in this study, and the external features of the four stages are exemplified in Fig.1. To characterize the physical properties of studied samples, the selected physical properties such as initial moisture content, mass, geometric mean diameter, sphericity and density of studied samples were measured using represented methods by Mohsenin (1896, Jahromi et al. (2008 and Shakeri and Khodabakhshian (2011. At least, the samples were kept at 5C in a refrigerator for 7 days to distribute the moisture uniformly throughout the sample. Before spectral acquisition, the required quantities of date fruits in each ripeness stage was taken out of the frig and allowed to warm with room temperature for approximately 2 hr (Khodabakhshian et al., 2012. Chemical properties measurements: Tissue samples were cut from each fruit separately and were macerated with a commercial juice extractor, filtered and centrifuged. The supernatant juice was used for the determination of sugar content with a manual refractometer, and expressed as percent Brix in the juice. Dry weight percentage of samples (Between 3-5 g was determined by weighing them first, then dried them at 105ºC in a forced-air oven for 4 h and finally reweighed. PH value of date fruits was determined by a pH meter. Raman spectroscopic set-up: FT-Raman spectra on the whole fruits in the region 200-2500 cm-1 were recorded using a Thermo Nicolet NEXUS 870 spectrometer (Thermo Electron Corp, Madison, Wis., U.S.A equipped

Multidimensional spectrometer

Science.gov (United States)

Zanni, Martin Thomas; Damrauer, Niels H.

2010-07-20

A multidimensional spectrometer for the infrared, visible, and ultraviolet regions of the electromagnetic spectrum, and a method for making multidimensional spectroscopic measurements in the infrared, visible, and ultraviolet regions of the electromagnetic spectrum. The multidimensional spectrometer facilitates measurements of inter- and intra-molecular interactions.

Nitric oxide-mediated bystander signal transduction induced by heavy-ion microbeam irradiation

Science.gov (United States)

Tomita, Masanori; Matsumoto, Hideki; Funayama, Tomoo; Yokota, Yuichiro; Otsuka, Kensuke; Maeda, Munetoshi; Kobayashi, Yasuhiko

2015-07-01

In general, a radiation-induced bystander response is known to be a cellular response induced in non-irradiated cells after receiving bystander signaling factors released from directly irradiated cells within a cell population. Bystander responses induced by high-linear energy transfer (LET) heavy ions at low fluence are an important health problem for astronauts in space. Bystander responses are mediated via physical cell-cell contact, such as gap-junction intercellular communication (GJIC) and/or diffusive factors released into the medium in cell culture conditions. Nitric oxide (NO) is a well-known major initiator/mediator of intercellular signaling within culture medium during bystander responses. In this study, we investigated the NO-mediated bystander signal transduction induced by high-LET argon (Ar)-ion microbeam irradiation of normal human fibroblasts. Foci formation by DNA double-strand break repair proteins was induced in non-irradiated cells, which were co-cultured with those irradiated by high-LET Ar-ion microbeams in the same culture plate. Foci formation was suppressed significantly by pretreatment with an NO scavenger. Furthermore, NO-mediated reproductive cell death was also induced in bystander cells. Phosphorylation of NF-κB and Akt were induced during NO-mediated bystander signaling in the irradiated and bystander cells. However, the activation of these proteins depended on the incubation time after irradiation. The accumulation of cyclooxygenase-2 (COX-2), a downstream target of NO and NF-κB, was observed in the bystander cells 6 h after irradiation but not in the directly irradiated cells. Our findings suggest that Akt- and NF-κB-dependent signaling pathways involving COX-2 play important roles in NO-mediated high-LET heavy-ion-induced bystander responses. In addition, COX-2 may be used as a molecular marker of high-LET heavy-ion-induced bystander cells to distinguish them from directly irradiated cells, although this may depend on the time

Small angle spectrometers: Summary

International Nuclear Information System (INIS)

Courant, E.; Foley, K.J.; Schlein, P.E.

1986-01-01

Aspects of experiments at small angles at the Superconducting Super Collider are considered. Topics summarized include a small angle spectrometer, a high contingency spectrometer, dipole and toroid spectrometers, and magnet choices

Microscopic residual stress evolution during deformation process of an Fe---Mn---Si---Cr shape memory alloy investigated using white X-ray microbeam diffraction

International Nuclear Information System (INIS)

Kwon, E.P.; Sato, S.; Fujieda, S.; Shinoda, K.; Kajiwara, K.; Sato, M.; Suzuki, S.

2013-01-01

Microscopic residual stress evolution in different austenite (γ) grains during shape memory process in an Fe---Mn---Si---Cr alloy was investigated using the white X-ray microbeam diffraction technique. The use of high-energy white X-ray microbeam with small beam size allowed us to measure the microscopic residual stress in coarse γ grains with specific orientation. After tensile deformation large compressive residual stress was evolved in γ grains due to the formation of stress-induced ε martensite, but upon recovery heating it almost disappeared as a result of reverse transformation of martensite. The magnitude of compressive residual stress was higher in grains with orientations close to 〈144〉 and 〈233〉 orientations than in a grain with near 〈001〉 orientation. Analysis of the microstructure of each grain using electron backscattering diffraction suggested that the difference in the magnitude of compressive residual stress could be attributed to different martensitic transformation characteristics in the grains

Raman fiber lasers

CERN Document Server

2017-01-01

This book serves as a comprehensive, up-to-date reference about this cutting-edge laser technology and its many new and interesting developments. Various aspects and trends of Raman fiber lasers are described in detail by experts in their fields. Raman fiber lasers have progressed quickly in the past decade, and have emerged as a versatile laser technology for generating high power light sources covering a spectral range from visible to mid-infrared. The technology is already being applied in the fields of telecommunication, astronomy, cold atom physics, laser spectroscopy, environmental sensing, and laser medicine. This book covers various topics relating to Raman fiber laser research, including power scaling, cladding and diode pumping, cascade Raman shifting, single frequency operation and power amplification, mid-infrared laser generation, specialty optical fibers, and random distributed feedback Raman fiber lasers. The book will appeal to scientists, students, and technicians seeking to understand the re...

Real-time observation of irradiated Hela-cell Modified by Fluorescent ubiquitination-based Cell Cycle Indicator Using Synchrotron X-Ray Microbeam

International Nuclear Information System (INIS)

Narita, A.; Noguchi, M.; Kaminaga, K.; Yokoya, A.; Kobayashi, K.; Usami, N.; Fujii, K.

2015-01-01

Fluorescent ubiquitination-based cell-cycle indicator (FUCCI) human cancer (HeLa) cells (red indicates G1; green, S/G2) were exposed to a synchrotron X-ray microbeam. Cells in either G1 or S/G2 were irradiated selectively according to their colour in the same microscopic field. Time-lapse micrographs of the irradiated cells were acquired for 24 h after irradiation. For fluorescent immunostaining, phosphorylated histone proteins (γ-H2AX) indicated the induction of DNA double-strand breaks. The cell cycle was arrested by irradiation at S/G2. In contrast, cells irradiated at G1 progressed to S/G2. The foci were induced in cells irradiated at both G1 and S/G2, suggesting that the G1-S (or S) checkpoint pathway does not function in HeLa cells due to the fact that the cells are functionally p53 deficient, even though X-ray microbeam irradiation significantly induces double-strand breaks. These results demonstrate that single FUCCI cell exposure and live cell imaging are powerful methods for studying the effects of radiation on the cell cycle. (authors)

Reduction of Raman scattering and fluorescence from anvils in high pressure Raman scattering

Science.gov (United States)

Dierker, S. B.; Aronson, M. C.

2018-05-01

We describe a new design and use of a high pressure anvil cell that significantly reduces the Raman scattering and fluorescence from the anvils in high pressure Raman scattering experiments. The approach is particularly useful in Raman scattering studies of opaque, weakly scattering samples. The effectiveness of the technique is illustrated with measurements of two-magnon Raman scattering in La2CuO4.

Demonstrated Wavelength Portability of Raman Reference Data for Explosives and Chemical Detection

Directory of Open Access Journals (Sweden)

Timothy J. Johnson

2012-01-01

Full Text Available As Raman spectroscopy continues to evolve, questions arise as to the portability of Raman data: dispersive versus Fourier transform, wavelength calibration, intensity calibration, and in particular the frequency of the excitation laser. While concerns about fluorescence arise in the visible or ultraviolet, most modern (portable systems use near-infrared excitation lasers, and many of these are relatively close in wavelength. We have investigated the possibility of porting reference data sets from one NIR wavelength system to another: We have constructed a reference library consisting of 145 spectra, including 20 explosives, as well as sundry other compounds and materials using a 1064 nm spectrometer. These data were used as a reference library to evaluate the same 145 compounds whose experimental spectra were recorded using a second 785 nm spectrometer. In 128 cases of 145 (or 88.3% including 20/20 for the explosives, the compounds were correctly identified with a mean “hit score” of 954 of 1000. Adding in criteria for when to declare a correct match versus when to declare uncertainty, the approach was able to correctly categorize 134 out of 145 spectra, giving a 92.4% accuracy. For the few that were incorrectly identified, either the matched spectra were spectroscopically similar to the target or the 785 nm signal was degraded due to fluorescence. The results indicate that imported data recorded at a different NIR wavelength can be successfully used as reference libraries, but key issues must be addressed: the reference data must be of equal or higher resolution than the resolution of the current sensor, the systems require rigorous wavelength calibration, and wavelength-dependent intensity response should be accounted for in the different systems.

The SPEDE spectrometer

Science.gov (United States)

Papadakis, P.; Cox, D. M.; O'Neill, G. G.; Borge, M. J. G.; Butler, P. A.; Gaffney, L. P.; Greenlees, P. T.; Herzberg, R.-D.; Illana, A.; Joss, D. T.; Konki, J.; Kröll, T.; Ojala, J.; Page, R. D.; Rahkila, P.; Ranttila, K.; Thornhill, J.; Tuunanen, J.; Van Duppen, P.; Warr, N.; Pakarinen, J.

2018-03-01

The electron spectrometer, SPEDE, has been developed and will be employed in conjunction with the Miniball spectrometer at the HIE-ISOLDE facility, CERN. SPEDE allows for direct measurement of internal conversion electrons emitted in-flight, without employing magnetic fields to transport or momentum filter the electrons. Together with the Miniball spectrometer, it enables simultaneous observation of γ rays and conversion electrons in Coulomb excitation experiments using radioactive ion beams.

PIXE microbeam analysis of the metallic debris release around endosseous implants

International Nuclear Information System (INIS)

Buso, G.P.; Galassini, S.; Moschini, G.; Passi, P.; Zadro, A.; Uzunov, N.M.; Doyle, B.L.; Rossi, P.; Provencio, P.

2005-01-01

The mechanical friction that occurs during the surgical insertion of endosseous implants, both in dentistry and orthopaedics, may cause the detachment of metal debris which are dislodged into the peri-implant tissues and can lead to adverse clinical effects. This phenomenon more likely happens with coated or roughened implants that are the most widely employed. In the present study were studied dental implants screws made of commercially pure titanium and coated using titanium plasma-spray (TPS) technique. The implants were inserted in the tibia of rabbits, and removed 'en bloc' with the surrounding bone after one month. After proper processing and mounting on plastic holders, samples from bones were analysed by EDXRF setup at of National Laboratories of Legnaro, INFN, Italy, and consequently at 3 MeV proton microbeam setup at Sandia National Laboratories. Elemental maps were drawn, showing some occasional presence of metal particles in the peri-implant bone

Study of a unique 16th century Antwerp majolica floor in the Rameyenhof castle's chapel by means of X-ray fluorescence and portable Raman analytical instrumentation

Energy Technology Data Exchange (ETDEWEB)

Van de Voorde, Lien, E-mail: lien.vandevoorde@ugent.be [Ghent University, Department of Analytical Chemistry, X-Ray Microspectroscopy and Imaging Research Group, Krijgslaan 281 S12, B-9000 Ghent (Belgium); Vandevijvere, Melissa [Ghent University, Department of Analytical Chemistry, X-Ray Microspectroscopy and Imaging Research Group, Krijgslaan 281 S12, B-9000 Ghent (Belgium); University of Antwerp, Faculty of Architecture and Design, Conservation Studies, Centre for Conservation Research (CCR), Blindestraat 9, 2000 Antwerp (Belgium); University of Antwerp, Department of Chemistry, X-ray and Instrumentation Lab (AXI2L), Groenenborgerlaan 171, 2020 Antwerp (Belgium); Vekemans, Bart [Ghent University, Department of Analytical Chemistry, X-Ray Microspectroscopy and Imaging Research Group, Krijgslaan 281 S12, B-9000 Ghent (Belgium); Van Pevenage, Jolien [Ghent University, Department of Analytical Chemistry, Raman Spectroscopy Research Group, Krijgslaan 281 S12, B-9000 Ghent (Belgium); Caen, Joost [University of Antwerp, Faculty of Architecture and Design, Conservation Studies, Centre for Conservation Research (CCR), Blindestraat 9, 2000 Antwerp (Belgium); Vandenabeele, Peter [Ghent University, Department of Archaeology, Archaeometry Research Group, Sint-Pietersnieuwstraat 35, B-9000 Ghent (Belgium); Van Espen, Piet [University of Antwerp, Department of Chemistry, X-ray and Instrumentation Lab (AXI2L), Groenenborgerlaan 171, 2020 Antwerp (Belgium); Vincze, Laszlo [Ghent University, Department of Analytical Chemistry, X-Ray Microspectroscopy and Imaging Research Group, Krijgslaan 281 S12, B-9000 Ghent (Belgium)

2014-12-01

The most unique and only known 16th century Antwerp majolica tile floor in Belgium is situated in a tower of the Rameyenhof castle (Gestel, Belgium). This exceptional work of art has recently been investigated in situ by using X-ray fluorescence (XRF) and Raman spectroscopy in order to study the material characteristics. This study reports on the result of the analyses based on the novel combination of non-destructive and portable instrumentation, including a handheld XRF spectrometer for obtaining elemental information and a mobile Raman spectrometer for retrieving structural and molecular information on the floor tiles in the Rameyenhof castle and on a second, similar medallion, which is stored in the Rubens House museum in Antwerp (Belgium). The investigated material, majolica, is a type of ceramic, which fascinated many people and potters throughout history by its beauty and colourful appearance. In this study the characteristic major/minor and trace element signature of 16th century Antwerp majolica is determined and the pigments used for the colourful paintings present on the floor are identified. Furthermore, based on the elemental fingerprint of the white glaze, and in particular on the presence of zinc in the tiles – an element that was not used for making 16th century majolica – valuable information about the originality of the chapel floor and the two central medallions is acquired. - Highlights: • In situ, non-destructive investigation of a unique Antwerp majolica floor • Multi-methodological approach: make use of a mobile Raman and X-ray spectrometer • Obtaining information about layered structure of Antwerp majolica • The used pigments in the majolica floor in Rameyenhof castle are characterized. • The verification of the authenticity of the floor and two central medallions are performed.

Ultrastructural changes in nucleoli and fibrillar centers under the effect of local ultraviolet microbeam irradiation of interphase culture cells

International Nuclear Information System (INIS)

Zatsepina, O.V.; Voronkova, L.N.; Sakharov, V.N.; Chentsov, Y.S.

1989-01-01

As shown previously, ultraviolet (uv) microbeam irradiation of one of the two mature nucleoli within an interphase cell nucleus causes significant diminution and inactivation of the irradiated nucleolus and compensatory growth and activation of the nonirradiated one. In the present work we describe the results of an ultrastructural study of this phenomenon. The changes in the nucleoli were examined by means of complete series of ultrathin sections obtained from seven irradiated pig kidney cells. The compensatory hypertrophy of the nonirradiated nucleoli is shown to be accompanied by a nearly twofold increase in the number of fibrillar centers (FCs) and by a decrease in their linear dimensions compared with the control cells of the same ploidy. In the degraded nucleoli the number of FCs decreases, but their dimensions increase. Ultraviolet microbeam irradiation causes dramatic diminution of the dense fibrillar component within the irradiated nucleoli as well. The nucleolar capacity for compensatory hypertrophy indicates that in addition to active ribosomal genes, mature nucleoli also contain silent genes capable of being activated under extreme conditions to sustain the required level of rRNA synthesis. It is assumed that activation of latent ribosomal genes is accompanied by FC fragmentation without a considerable increase in their total volume per cell

Utilizing Raman Spectroscopy and Surface-Enhanced Raman Spectroscopy to investigate healthy and cancerous colon samples

International Nuclear Information System (INIS)

Barzegar, A.; Rezaei, H.; Malekfar, R.

2012-01-01

In this study, spontaneous Raman scattering and surface-enhanced Raman scattering, Surface-Enhanced Raman Spectroscopy spectra have been investigated. The samples which were kept in the formalin solution selected from the human's healthy and cancerous colon tissues. The Surface-Enhanced Raman Spectroscopy spectra were collected by adding colloidal solution contained silver nanoparticles to the top of the samples. The recorded spectra were compared for the spontaneous Raman spectra of healthy and cancerous colon samples. The spontaneous and surface enhanced Raman scattering data were also collected and compared for both healthy and damaged samples.

Femtosecond Laser Fabricated Ag@Au and Cu@Au Alloy Nanoparticles for Surface Enhanced Raman Spectroscopy Based Trace Explosives Detection

Directory of Open Access Journals (Sweden)

Moram Sree Satya Bharati

2018-03-01

Full Text Available Herein we present results from our detailed studies on the fabrication of Ag@Au and Cu@Au alloy nanoparticles (NPs using the femtosecond laser ablation in liquid technique. The NPs were obtained by ablating the pure Ag, Cu targets (bulk in HAuCl4 (5 mM solution. The absorption properties of the obtained NPs colloids were characterized using UV-Visible absorption spectrometer and their size, shape, and crystallinity were investigated using the XRD, FESEM and TEM techniques. The fabricated NPs were utilized for sensing of explosive molecules such as 2,4,6-trinitrophenol (PA, 2,4-dinitrotoluene (DNT and a common dye methylene blue (MB using the surface enhanced Raman spectroscopy (SERS technique. The detection limit in terms of weight was as low as few nano-grams in the case of nitroaromatic explosive compounds (PA, DNT and few picograms in the case of a common dye molecule (MB. Typical enhancement factors achieved were estimated to be ~104, ~105, and ~107, respectively, for PA, DNT, and MB. The significance of the present work lies in exploring the performance of the prepared NPs being used as SERS substrates for explosives detection using a portable Raman instrument. Such capability enables one to carry the spectrometer to the point of interest in the field and evaluate any hazardous samples within a short period of time.

Raman Spectroscopy for Homeland Security Applications

Directory of Open Access Journals (Sweden)

Gregory Mogilevsky

2012-01-01

Full Text Available Raman spectroscopy is an analytical technique with vast applications in the homeland security and defense arenas. The Raman effect is defined by the inelastic interaction of the incident laser with the analyte molecule’s vibrational modes, which can be exploited to detect and identify chemicals in various environments and for the detection of hazards in the field, at checkpoints, or in a forensic laboratory with no contact with the substance. A major source of error that overwhelms the Raman signal is fluorescence caused by the background and the sample matrix. Novel methods are being developed to enhance the Raman signal’s sensitivity and to reduce the effects of fluorescence by altering how the hazard material interacts with its environment and the incident laser. Basic Raman techniques applicable to homeland security applications include conventional (off-resonance Raman spectroscopy, surface-enhanced Raman spectroscopy (SERS, resonance Raman spectroscopy, and spatially or temporally offset Raman spectroscopy (SORS and TORS. Additional emerging Raman techniques, including remote Raman detection, Raman imaging, and Heterodyne imaging, are being developed to further enhance the Raman signal, mitigate fluorescence effects, and monitor hazards at a distance for use in homeland security and defense applications.

Combined Raman spectroscopy and first-principles calculation for essential oil of Lemongrass

Science.gov (United States)

Faria, Rozilaine A. P. G.; Picanço, Nágela F. M.; Campo, Gladís S. D. L.; Faria, Jorge L. B.; Instituto de Física/UFMT Collaboration; Instituto Federal de Mato Grosso/IFMT Team

2014-03-01

The essential oils have increased food's industry interest by the presence of antioxidant and antimicrobial. Many of them have antimicrobial and antioxidant, antibacterial and antifungal activities. But, due to the concentrations required to be added in the food matrix, the sensory quality of the food is changed. The production and composition of essential oil extracted from plants depend on the plant-environment interactions, the harvest season, phenophase and physiological state of the vegetal. Cymbopogom citratus (Lemongrass) has a good yield in essential oil with neral (citral A), geranial (citral B) and myrcene, reaching 90% of the oil composition. In our experimental work, the essential oil of lemongrass was obtained by hydrodistillation in Clevenger apparatus for 4 hours. The compound was further analyzed by Raman scattering in a spectrometer HR 800, with excitation at 633nm, in the range 80-3400 cm-1. The spectrum obtained was compared with DFT calculations of molecules of the oil components. Our results show the vibrational signatures of the main functional groups and suggest a simple, but very useful, methodology to quantify the proportions of these components in the oil composition, showing good agreement with Raman data. CNPq/Capes/Fapemat.

Sub-millisecond time-resolved SAXS using a continuous-flow mixer and X-ray microbeam

International Nuclear Information System (INIS)

Graceffa, Rita; Nobrega, R. Paul; Barrea, Raul A.; Kathuria, Sagar V.; Chakravarthy, Srinivas; Bilsel, Osman; Irving, Thomas C.

2013-01-01

The development of a high-duty-cycle microsecond time-resolution SAXS capability at the Biophysics Collaborative Access Team beamline (BioCAT) 18ID at the Advanced Photon Source, Argonne National Laboratory, USA, is reported. Small-angle X-ray scattering (SAXS) is a well established technique to probe the nanoscale structure and interactions in soft matter. It allows one to study the structure of native particles in near physiological environments and to analyze structural changes in response to variations in external conditions. The combination of microfluidics and SAXS provides a powerful tool to investigate dynamic processes on a molecular level with sub-millisecond time resolution. Reaction kinetics in the sub-millisecond time range has been achieved using continuous-flow mixers manufactured using micromachining techniques. The time resolution of these devices has previously been limited, in part, by the X-ray beam sizes delivered by typical SAXS beamlines. These limitations can be overcome using optics to focus X-rays to the micrometer size range providing that beam divergence and photon flux suitable for performing SAXS experiments can be maintained. Such micro-SAXS in combination with microfluidic devices would be an attractive probe for time-resolved studies. Here, the development of a high-duty-cycle scanning microsecond-time-resolution SAXS capability, built around the Kirkpatrick–Baez mirror-based microbeam system at the Biophysics Collaborative Access Team (BioCAT) beamline 18ID at the Advanced Photon Source, Argonne National Laboratory, is reported. A detailed description of the microbeam small-angle-scattering instrument, the turbulent flow mixer, as well as the data acquisition and control and analysis software is provided. Results are presented where this apparatus was used to study the folding of cytochrome c. Future prospects for this technique are discussed

Sub-millisecond time-resolved SAXS using a continuous-flow mixer and X-ray microbeam

Energy Technology Data Exchange (ETDEWEB)

Graceffa, Rita, E-mail: rita.graceffa@gmail.com [Illinois Institute of Technology, 3101 South Dearborn, Chicago, IL 60616 (United States); Nobrega, R. Paul [University of Massachusetts Medical School, 364 Plantation Street, LRB 919, Worcester, MA 01605 (United States); Barrea, Raul A. [Illinois Institute of Technology, 3101 South Dearborn, Chicago, IL 60616 (United States); Kathuria, Sagar V. [University of Massachusetts Medical School, 364 Plantation Street, LRB 919, Worcester, MA 01605 (United States); Chakravarthy, Srinivas [Illinois Institute of Technology, 3101 South Dearborn, Chicago, IL 60616 (United States); Bilsel, Osman [University of Massachusetts Medical School, 364 Plantation Street, LRB 919, Worcester, MA 01605 (United States); Irving, Thomas C. [Illinois Institute of Technology, 3101 South Dearborn, Chicago, IL 60616 (United States)

2013-11-01

The development of a high-duty-cycle microsecond time-resolution SAXS capability at the Biophysics Collaborative Access Team beamline (BioCAT) 18ID at the Advanced Photon Source, Argonne National Laboratory, USA, is reported. Small-angle X-ray scattering (SAXS) is a well established technique to probe the nanoscale structure and interactions in soft matter. It allows one to study the structure of native particles in near physiological environments and to analyze structural changes in response to variations in external conditions. The combination of microfluidics and SAXS provides a powerful tool to investigate dynamic processes on a molecular level with sub-millisecond time resolution. Reaction kinetics in the sub-millisecond time range has been achieved using continuous-flow mixers manufactured using micromachining techniques. The time resolution of these devices has previously been limited, in part, by the X-ray beam sizes delivered by typical SAXS beamlines. These limitations can be overcome using optics to focus X-rays to the micrometer size range providing that beam divergence and photon flux suitable for performing SAXS experiments can be maintained. Such micro-SAXS in combination with microfluidic devices would be an attractive probe for time-resolved studies. Here, the development of a high-duty-cycle scanning microsecond-time-resolution SAXS capability, built around the Kirkpatrick–Baez mirror-based microbeam system at the Biophysics Collaborative Access Team (BioCAT) beamline 18ID at the Advanced Photon Source, Argonne National Laboratory, is reported. A detailed description of the microbeam small-angle-scattering instrument, the turbulent flow mixer, as well as the data acquisition and control and analysis software is provided. Results are presented where this apparatus was used to study the folding of cytochrome c. Future prospects for this technique are discussed.

671-nm microsystem diode laser based on portable Raman sensor device for in-situ identification of meat spoilage

Science.gov (United States)

Sowoidnich, Kay; Schmidt, Heinar; Schwägele, Fredi; Kronfeldt, Heinz-Detlef

2011-05-01

Based on a miniaturized optical bench with attached 671 nm microsystem diode laser we present a portable Raman system for the rapid in-situ characterization of meat spoilage. It consists of a handheld sensor head (dimensions: 210 x 240 x 60 mm3) for Raman signal excitation and collection including the Raman optical bench, a laser driver, and a battery pack. The backscattered Raman radiation from the sample is analyzed by means of a custom-designed miniature spectrometer (dimensions: 200 x 190 x 70 mm3) with a resolution of 8 cm-1 which is fiber-optically coupled to the sensor head. A netbook is used to control the detector and for data recording. Selected cuts from pork (musculus longissimus dorsi and ham) stored refrigerated at 5 °C were investigated in timedependent measurement series up to three weeks to assess the suitability of the system for the rapid detection of meat spoilage. Using a laser power of 100 mW at the sample meat spectra can be obtained with typical integration times of 5 - 10 seconds. The complex spectra were analyzed by the multivariate statistical tool PCA (principal components analysis) to determine the spectral changes occurring during the storage period. Additionally, the Raman data were correlated with reference analyses performed in parallel. In that way, a distinction between fresh and spoiled meat can be found in the time slot of 7 - 8 days after slaughter. The applicability of the system for the rapid spoilage detection of meat and other food products will be discussed.

A study with microbeam PIXE technique needed for the interpretation of data on pollutants in hair obtained with NAA and other bulk concentration analysis. Part of a coordinated programme on nuclear-based methods for analysis of pollutants in human hair

International Nuclear Information System (INIS)

Houtman, J.P.W.

1981-01-01

Hair metals the analysis of which has been proposed as a practical method for assaying human contamination with metal pollutants, reflect both internal and external contamination. This study is an attempt to distinguish these two components of hair metals, using the scanning microbeam PIXE technique. Individual hair strands were embedded in a resin combined with a hardener. Each embedded hair strand was cut perpendicular to its axis, into the root, 1-cm and 2-cm segments from the root. The 3 segments were analysed for few elements including As and Pb, using the scanning microbeam PIXE technique. For each segment, a proton microbeam of 15μ diameter and 500Hz frequency was used to scan the segment cross-section along the long axis. X-ray spectrometry was used to determine the concentrations of the elements studied. The results, although preliminary, showed that the scanning microbeam PIXE technique may provide important information about elemental concentrations and distribution patterns along hair length and hair cross-section. This may lead to a better understanding of mechanisms responsible for the deposition of elements into hair and thereby to a more rational use of hair analysis as a method for assaying human exposure to element pollutants

Introductory Raman spectroscopy

CERN Document Server

Ferraro, John R

2012-01-01

Praise for Introductory Raman Spectroscopy Highlights basic theory, which is treated in an introductory fashion Presents state-of-the-art instrumentation Discusses new applications of Raman spectroscopy in industry and research.

Characterization of excited electronic states of naphthalene by resonance Raman and hyper-Raman scattering

International Nuclear Information System (INIS)

Bonang, C.C.; Cameron, S.M.

1992-01-01

The first resonance Raman and hyper-Raman scattering from naphthalene are reported. Fourth harmonic of a mode-locked Nd:YAG laser is used to resonantly excite the 1 B 1u + transition, producing Raman spectra that confirm the dominance of the vibronically active ν 28 (b 3g ) mode and the Franck--Condon active a g modes, ν 5 and ν 3 . A synchronously pumped stilbene dye laser and its second harmonic are employed as the excitation sources for hyper-Raman and Raman scattering from the overlapping 1 B 2 u + and 1 A g - states. The Raman spectra indicate that the equilibrium geometry of naphthalene is distorted primarily along ν 5 , ν 8 , and ν 7 normal coordinates upon excitation to 1 B 2 u + . The hyper-Raman spectrum shows that ν 25 (b 2u ) is the mode principally responsible for vibronic coupling between the 1 A g - and 1 B 2u + states. The results demonstrate the advantageous features of resonance hyper-Raman scattering for the case of overlapping one- and two-photon allowed transitions. Calculations based on simple molecular orbital configurations are shown to qualitatively agree with the experimental results

Graphitized silicon carbide microbeams: wafer-level, self-aligned graphene on silicon wafers

International Nuclear Information System (INIS)

Cunning, Benjamin V; Ahmed, Mohsin; Mishra, Neeraj; Kermany, Atieh Ranjbar; Iacopi, Francesca; Wood, Barry

2014-01-01

Currently proven methods that are used to obtain devices with high-quality graphene on silicon wafers involve the transfer of graphene flakes from a growth substrate, resulting in fundamental limitations for large-scale device fabrication. Moreover, the complex three-dimensional structures of interest for microelectromechanical and nanoelectromechanical systems are hardly compatible with such transfer processes. Here, we introduce a methodology for obtaining thousands of microbeams, made of graphitized silicon carbide on silicon, through a site-selective and wafer-scale approach. A Ni-Cu alloy catalyst mediates a self-aligned graphitization on prepatterned SiC microstructures at a temperature that is compatible with silicon technologies. The graphene nanocoating leads to a dramatically enhanced electrical conductivity, which elevates this approach to an ideal method for the replacement of conductive metal films in silicon carbide-based MEMS and NEMS devices. (paper)

Raman spectroscopy in graphene

International Nuclear Information System (INIS)

Malard, L.M.; Pimenta, M.A.; Dresselhaus, G.; Dresselhaus, M.S.

2009-01-01

Recent Raman scattering studies in different types of graphene samples are reviewed here. We first discuss the first-order and the double resonance Raman scattering mechanisms in graphene, which give rise to the most prominent Raman features. The determination of the number of layers in few-layer graphene is discussed, giving special emphasis to the possibility of using Raman spectroscopy to distinguish a monolayer from few-layer graphene stacked in the Bernal (AB) configuration. Different types of graphene samples produced both by exfoliation and using epitaxial methods are described and their Raman spectra are compared with those of 3D crystalline graphite and turbostratic graphite, in which the layers are stacked with rotational disorder. We show that Resonance Raman studies, where the energy of the excitation laser line can be tuned continuously, can be used to probe electrons and phonons near the Dirac point of graphene and, in particular allowing a determination to be made of the tight-binding parameters for bilayer graphene. The special process of electron-phonon interaction that renormalizes the phonon energy giving rise to the Kohn anomaly is discussed, and is illustrated by gated experiments where the position of the Fermi level can be changed experimentally. Finally, we discuss the ability of distinguishing armchair and zig-zag edges by Raman spectroscopy and studies in graphene nanoribbons in which the Raman signal is enhanced due to resonance with singularities in the density of electronic states.

Synchrotron X-ray micro-beam studies of ancient Egyptian make-up

International Nuclear Information System (INIS)

Martinetto, P.; Anne, M.; Dooryhee, E.; Drakopoulos, M.; Dubus, M.; Salomon, J.; Simionovici, A.; Walter, Ph.

2001-01-01

Vases full of make-up are most often present in the burial furniture of Egyptian tombs dated from the pharaonic period. The powdered cosmetics made of isolated grains are analysed to identify their trace element signature. From this signature we identify the provenance of the mineral ingredients in the make-up and we observe different impurities in products, which have been demonstrated as synthetic substances by previous works. Focused X-ray micro-beam (2x5 μm 2 ) is successively tuned at 11 keV, below the L III absorption edge of Pb, and 31.8 keV for global characterisation of the metal impurities. The fluorescence signal integrated over each single grain is detected against the X-ray micro-diffraction pattern collected in transmission with a bi-dimensional detector. Furthermore, for galena grains rich in Zn, the XANES signal at the K-absorption edge of Zn shows its immediate nearest-neighbour environment

Synchrotron X-ray micro-beam studies of ancient Egyptian make-up

Science.gov (United States)

Martinetto, P.; Anne, M.; Dooryhée, E.; Drakopoulos, M.; Dubus, M.; Salomon, J.; Simionovici, A.; Walter, Ph.

2001-07-01

Vases full of make-up are most often present in the burial furniture of Egyptian tombs dated from the pharaonic period. The powdered cosmetics made of isolated grains are analysed to identify their trace element signature. From this signature we identify the provenance of the mineral ingredients in the make-up and we observe different impurities in products, which have been demonstrated as synthetic substances by previous works. Focused X-ray micro-beam ( 2×5 μm2) is successively tuned at 11 keV, below the L III absorption edge of Pb, and 31.8 keV for global characterisation of the metal impurities. The fluorescence signal integrated over each single grain is detected against the X-ray micro-diffraction pattern collected in transmission with a bi-dimensional detector. Furthermore, for galena grains rich in Zn, the XANES signal at the K-absorption edge of Zn shows its immediate nearest-neighbour environment.

Synchrotron X-ray micro-beam studies of ancient Egyptian make-up

Energy Technology Data Exchange (ETDEWEB)

Martinetto, P; Anne, M; Dooryhee, E; Drakopoulos, M; Dubus, M; Salomon, J; Simionovici, A; Walter, Ph

2001-07-01

Vases full of make-up are most often present in the burial furniture of Egyptian tombs dated from the pharaonic period. The powdered cosmetics made of isolated grains are analysed to identify their trace element signature. From this signature we identify the provenance of the mineral ingredients in the make-up and we observe different impurities in products, which have been demonstrated as synthetic substances by previous works. Focused X-ray micro-beam (2x5 {mu}m{sup 2}) is successively tuned at 11 keV, below the L{sub III} absorption edge of Pb, and 31.8 keV for global characterisation of the metal impurities. The fluorescence signal integrated over each single grain is detected against the X-ray micro-diffraction pattern collected in transmission with a bi-dimensional detector. Furthermore, for galena grains rich in Zn, the XANES signal at the K-absorption edge of Zn shows its immediate nearest-neighbour environment.

The SAGE spectrometer

Energy Technology Data Exchange (ETDEWEB)

Pakarinen, J.; Papadakis, P. [University of Liverpool, Department of Physics, Oliver Lodge Laboratory, Liverpool (United Kingdom); University of Jyvaeskylae, Department of Physics, Jyvaeskylae (Finland); Sorri, J.; Greenlees, P.T.; Jones, P.; Julin, R.; Konki, J.; Rahkila, P.; Sandzelius, M. [University of Jyvaeskylae, Department of Physics, Jyvaeskylae (Finland); Herzberg, R.D.; Butler, P.A.; Cox, D.M.; Cresswell, J.R.; Mistry, A.; Page, R.D.; Parr, E.; Sampson, J.; Seddon, D.A.; Thornhill, J.; Wells, D. [University of Liverpool, Department of Physics, Oliver Lodge Laboratory, Liverpool (United Kingdom); Coleman-Smith, P.J.; Lazarus, I.H.; Letts, S.C.; Pucknell, V.F.E.; Simpson, J. [STFC Daresbury Laboratory, Warrington (United Kingdom)

2014-03-15

The SAGE spectrometer has been constructed for in-beam nuclear structure studies. SAGE combines a Ge-detector array and an electron spectrometer for detection of γ-rays and internal conversion electrons, respectively, and allows simultaneous observation of both electrons and γ-rays emitted from excited nuclei. SAGE is set up in the Accelerator Laboratory of the University of Jyvaeskylae and works in conjunction with the RITU gas-filled recoil separator and the GREAT focal-plane spectrometer allowing the use of the recoil-decay tagging method. (orig.)

The SAGE spectrometer

International Nuclear Information System (INIS)

Pakarinen, J.; Papadakis, P.; Sorri, J.; Greenlees, P.T.; Jones, P.; Julin, R.; Konki, J.; Rahkila, P.; Sandzelius, M.; Herzberg, R.D.; Butler, P.A.; Cox, D.M.; Cresswell, J.R.; Mistry, A.; Page, R.D.; Parr, E.; Sampson, J.; Seddon, D.A.; Thornhill, J.; Wells, D.; Coleman-Smith, P.J.; Lazarus, I.H.; Letts, S.C.; Pucknell, V.F.E.; Simpson, J.

2014-01-01

The SAGE spectrometer has been constructed for in-beam nuclear structure studies. SAGE combines a Ge-detector array and an electron spectrometer for detection of γ-rays and internal conversion electrons, respectively, and allows simultaneous observation of both electrons and γ-rays emitted from excited nuclei. SAGE is set up in the Accelerator Laboratory of the University of Jyvaeskylae and works in conjunction with the RITU gas-filled recoil separator and the GREAT focal-plane spectrometer allowing the use of the recoil-decay tagging method. (orig.)

Raman spectroscopy an intensity approach

CERN Document Server

Guozhen, Wu

2017-01-01

This book summarizes the highlights of our work on the bond polarizability approach to the intensity analysis. The topics covered include surface enhanced Raman scattering, Raman excited virtual states and Raman optical activity (ROA). The first chapter briefly introduces the Raman effect in a succinct but clear way. Chapter 2 deals with the normal mode analysis. This is a basic tool for our work. Chapter 3 introduces our proposed algorithm for the Raman intensity analysis. Chapter 4 heavily introduces the physical picture of Raman virtual states. Chapter 5 offers details so that the readers can have a comprehensive idea of Raman virtual states. Chapter 6 demonstrates how this bond polarizability algorithm is extended to ROA intensity analysis. Chapters 7 and 8 offer details on ROA, showing many findings on ROA mechanism that were not known or neglected before. Chapter 9 introduces our proposed classical treatment on ROA which, as combined with the results from the bond polarizability analysis, leads to a com...

Identification of cave minerals by Raman spectroscopy: new technology for non-destructive analysis

Directory of Open Access Journals (Sweden)

White William B.

2006-07-01

Full Text Available The usual tools are X-ray powder diffraction, the optical microscope, and the scanning electron microscope. X-ray diffraction gives a definitive fingerprint by which the mineral can be identified by comparison with a catalog of reference patterns. However, samples must be ground to powder and unstable hydrated minerals may decompose before analysis is complete. Raman spectroscopy also provides a fingerprint useful for mineral identification but with the additional advantage that some a-priori interpretation of the spectra is possible (distinguishing carbonates from sulfates, for example. Because excitation of the spectra is by means of a laser beam, it is possible to measure the spectra of samples in sealed glass containers, thus preserving unstable samples. Because laser beams can be focused, spectra can be obtained from individual grains. New technology has reduced the size of the instrument and also the sensitivity of the optical system to vibration and transport so that a portable instrument has become possible. The sampling probe is linked to the spectrometer by optical fibers so that large specimens can be examined without damage. Comparative spectra of common cave minerals demonstrate the value of Raman spectra as an identification technique.

Biomedical Applications of Micro-Raman and Surface-Enhanced Raman Scattering (SERS) Technology

Science.gov (United States)

2012-10-01

hydroxyapatite ; 1073cm-1, carbonate from carbonate apatite; 1442cm-1, cholesterol and cholesterol esters. 17 Table 1. Tentative assignment and Raman peak...allowed for the discrete location of atherosclerotic plaques. Raman peaks at 961 and 1073 cm-1 reveal the presence of calcium hydroxyapatite and... hydroxyapatite are located within the vessel wall. Similarly, Fig. 5 maps the Raman intensity of the peak at 1073cm-1, which is indicative of

Differential diagnosis in primary and metastatic cutaneous melanoma by FT-Raman spectroscopy Diagnóstico diferencial no melanoma primário e metastático por espectroscopia FT-Raman

Directory of Open Access Journals (Sweden)

Andrea Fernandes de Oliveira

2010-10-01

Full Text Available PURPOSE: To qualify the FT-Raman spectral data of primary and metastatic cutaneous melanoma in order to obtain a differential diagnosis. METHODS: Ten normal human skin samples without any clinical or histopathological alterations, ten cutaneous melanoma fragments, and nine lymph node metastasis samples were used; 105, 140 and 126 spectra were obtained respectively. Each sample was divided into 2 or 3 fragments of approximately 2 mm³ and positioned in the Raman spectrometer sample holder in order to obtain the spectra; a monochrome laser light Nd:YAG at 1064 nm was used to excite the inelastic effect. RESULTS: To differentiate the three histopathological groups according to their characteristics extracted from the spectra, data discriminative analysis was undertaken. Phenylalanine, DNA, and Amide-I spectral variables stood out in the differentiation of the three groups. The percentages of correctly classified groups based on Phenylalanine, DNA, and Amide-I spectral features was 93.1%. CONCLUSION: FT-Raman spectroscopy is capable of differentiating melanoma from its metastasis, as well as from normal skin.OBJETIVO: Qualificar os dados espectrais FT-Raman do melanoma cutâneo primário e metastático e assim realizar o diagnóstico diferencial. MÉTODOS: Foram utilizadas amostras de 10 fragmentos de pele sem alterações clínicas ou histopatológicas, 10 de melanomas cutâneos e 9 de metástases linfonodais; 105, 140 and 126 espectros foram obtidos respectivamente. Cada amostra foi dividida em 2 ou 3 frações de 2 mm³ e posicionada no porta amostras do espectrômetro Raman para obtenção dos espectros, por meio da excitação do espalhamento inelástico pelo laser de Nd:YAG em 1064 nm incididos na amostra. RESULTADOS: Para diferenciar os três grupos formados de acordo com as características fornecidas pelos espectros, realizamos a análise discriminante dos dados. As variáveis espectrais Fenilalanina, DNA e Amida-I se destacaram na

Mode-dependent dispersion in Raman line shapes: Observation and implications from ultrafast Raman loss spectroscopy

International Nuclear Information System (INIS)

Umapathy, S.; Mallick, B.; Lakshmanna, A.

2010-01-01

Ultrafast Raman loss spectroscopy (URLS) enables one to obtain the vibrational structural information of molecular systems including fluorescent materials. URLS, a nonlinear process analog to stimulated Raman gain, involves a narrow bandwidth picosecond Raman pump pulse and a femtosecond broadband white light continuum. Under nonresonant condition, the Raman response appears as a negative (loss) signal, whereas, on resonance with the electronic transition the line shape changes from a negative to a positive through a dispersive form. The intensities observed and thus, the Franck-Condon activity (coordinate dependent), are sensitive to the wavelength of the white light corresponding to a particular Raman frequency with respect to the Raman pump pulse wavelength, i.e., there is a mode-dependent response in URLS.

Confocal Raman microscopy

CERN Document Server

Dieing, Thomas; Hollricher, Olaf

2018-01-01

This second edition provides a cutting-edge overview of physical, technical and scientific aspects related to the widely used analytical method of confocal Raman microscopy. The book includes expanded background information and adds insights into how confocal Raman microscopy, especially 3D Raman imaging, can be integrated with other methods to produce a variety of correlative microscopy combinations. The benefits are then demonstrated and supported by numerous examples from the fields of materials science, 2D materials, the life sciences, pharmaceutical research and development, as well as the geosciences.

Raman Optical Activity and Raman Spectra of Amphetamine Species

DEFF Research Database (Denmark)

Berg, Rolf W.; Shim, Irene; White, Peter Cyril

2012-01-01

Theoretical calculations and preliminary measurements of vibrational Raman optical activity (ROA) spectra of different species of amphetamine (amphetamine and amphetamine-H+) are reported for the first time. The quantum chemical calculations were carried out as hybrid ab initio DFT-molecular orbi......Theoretical calculations and preliminary measurements of vibrational Raman optical activity (ROA) spectra of different species of amphetamine (amphetamine and amphetamine-H+) are reported for the first time. The quantum chemical calculations were carried out as hybrid ab initio DFT...... are employed for identification purposes. The DFT calculations show that the most stable conformations are those allowing for close contact between the aromatic ring and the amine hydrogen atoms. The internal rotational barrier within the same amphetamine enanti- omer has a considerable influence on the Raman...

Flexoelectric Effect on Vibration of Piezoelectric Microbeams Based on a Modified Couple Stress Theory

Directory of Open Access Journals (Sweden)

Xingjia Li

2017-01-01

Full Text Available A novel electric Gibbs function was proposed for the piezoelectric microbeams (PMBs by employing a modified couple stress theory. Based on the new Gibbs function and the Euler-Bernoulli beam theory, the governing equations which incorporate the effects of couple stress, flexoelectricity, and piezoelectricity were derived for the mechanics of PMBs. The analysis of the effective bending rigidity shows the effects of size and flexoelectricity can greaten the stiffness of PMBs so that the natural frequency increases significantly compared with the Euler-Bernoulli beam, and then the mechanical and electrical properties of PMBs are enhanced compared to the classical beam. This study can guide the design of microscale piezoelectric/flexoelectric structures which may find potential applications in the microelectromechanical systems (MEMS.

Development of Femtosecond Stimulated Raman Spectroscopy: Stimulated Raman Gain via Elimination of Cross Phase Modulation

International Nuclear Information System (INIS)

Jin, Seung Min; Lee, Young Jong; Yu, Jong Wan; Kim, Seong Keun

2004-01-01

We have developed a new femtosecond probe technique by using stimulated Raman spectroscopy. The cross phase modulation in femtosecond time scale associated with off-resonant interaction was shown to be eliminated by integrating the transient gain/loss signal over the time delay between the Raman pump pulse and the continuum pulse. The stimulated Raman gain of neat cyclohexane was obtained to demonstrate the feasibility of the technique. Spectral and temporal widths of stimulated Raman spectra were controlled by using a narrow band pass filter. Femtosecond stimulated Raman spectroscopy was proposed as a highly useful probe in time-resolved vibrational spectroscopy

Raman Imaging Techniques and Applications

CERN Document Server

2012-01-01

Raman imaging has long been used to probe the chemical nature of a sample, providing information on molecular orientation, symmetry and structure with sub-micron spatial resolution. Recent technical developments have pushed the limits of micro-Raman microscopy, enabling the acquisition of Raman spectra with unprecedented speed, and opening a pathway to fast chemical imaging for many applications from material science and semiconductors to pharmaceutical drug development and cell biology, and even art and forensic science. The promise of tip-enhanced raman spectroscopy (TERS) and near-field techniques is pushing the envelope even further by breaking the limit of diffraction and enabling nano-Raman microscopy.

The Omicron Spectrometer

CERN Document Server

Allardyce, B W

1976-01-01

It is intended to build a spectrometer with a large solid angle and a large momentum acceptance at the reconstructed synchrocyclotron at CERN. This spectrometer will have an energy resolution of about 1 MeV for particles with momenta up to about 400 MeV/c.

Optical trapping and Raman spectroscopy of single nanostructures using standing-wave Raman tweezers

Science.gov (United States)

Wu, Mu-ying; He, Lin; Chen, Gui-hua; Yang, Guang; Li, Yong-qing

2017-08-01

Optical tweezers integrated with Raman spectroscopy allows analyzing a single trapped micro-particle, but is generally less effective for individual nano-sized objects in the 10-100 nm range. The main challenge is the weak gradient force on nanoparticles that is insufficient to overcome the destabilizing effect of scattering force and Brownian motion. Here, we present standing-wave Raman tweezers for stable trapping and sensitive characterization of single isolated nanostructures with a low laser power by combining a standing-wave optical trap (SWOT) with confocal Raman spectroscopy. This scheme has stronger intensity gradients and balanced scattering forces, and thus is more stable and sensitive in measuring nanoparticles in liquid with 4-8 fold increase in the Raman signals. It can be used to analyze many nanoparticles that cannot be measured with single-beam Raman tweezers, including individual single-walled carbon nanotubes (SWCNT), graphene flakes, biological particles, polystyrene beads (100 nm), SERS-active metal nanoparticles, and high-refractive semiconductor nanoparticles with a low laser power of a few milliwatts. This would enable sorting and characterization of specific SWCNTs and other nanoparticles based on their increased Raman fingerprints.

A gamma scintillation spectrometer

Energy Technology Data Exchange (ETDEWEB)

Symbalisty, S

1952-07-01

A scintillation type gamma ray spectrometer employing coincidence counting, designed and built at the Physics Department of the University of Western Ontario is described. The spectrometer is composed of two anthracene and photomultiplier radiation detectors, two pulse analyzing channels, a coincidence stage, three scalers and a high voltage stabilized supply. A preliminary experiment to test the operation of the spectrometer was performed and the results of this test are presented. (author)

Acquisition of HPLC-Mass Spectrometer

Science.gov (United States)

2015-08-18

31-Jan-2015 Approved for Public Release; Distribution Unlimited Final Report: Acquisition of HPLC -Mass Spectrometer The views, opinions and/or findings...published in peer-reviewed journals: Final Report: Acquisition of HPLC -Mass Spectrometer Report Title The acquisition of the mass spectrometer has been a

UV Raman lidar measurements of relative humidity for the characterization of cirrus cloud microphysical properties

Directory of Open Access Journals (Sweden)

G. Masiello

2009-11-01

Full Text Available Raman lidar measurements performed in Potenza by the Raman lidar system BASIL in the presence of cirrus clouds are discussed. Measurements were performed on 6 September 2004 in the frame of the Italian phase of the EAQUATE Experiment.

The major feature of BASIL is represented by its capability to perform high-resolution and accurate measurements of atmospheric temperature and water vapour, and consequently relative humidity, both in daytime and night-time, based on the application of the rotational and vibrational Raman lidar techniques in the UV. BASIL is also capable to provide measurements of the particle backscatter and extinction coefficient, and consequently lidar ratio (at the time of these measurements, only at one wavelength, which are fundamental to infer geometrical and microphysical properties of clouds.

A case study is discussed in order to assess the capability of Raman lidars to measure humidity in presence of cirrus clouds, both below and inside the cloud. While air inside the cloud layers is observed to be always under-saturated with respect to water, both ice super-saturation and under-saturation conditions are found inside these clouds. Upper tropospheric moistening is observed below the lower cloud layer.

The synergic use of the data derived from the ground based Raman Lidar and of spectral radiances measured by the NAST-I Airborne Spectrometer allows the determination of the temporal evolution of the atmospheric cooling/heating rates due to the presence of the cirrus cloud.

Lidar measurements beneath the cirrus cloud layer have been interpreted using a 1-D cirrus cloud model with explicit microphysics. The 1-D simulations indicate that sedimentation-moistening has contributed significantly to the moist anomaly, but other mechanisms are also contributing. This result supports the hypothesis that the observed mid-tropospheric humidification is a real feature which is

Fourier Transform Spectrometer System

Science.gov (United States)

Campbell, Joel F. (Inventor)

2014-01-01

A Fourier transform spectrometer (FTS) data acquisition system includes an FTS spectrometer that receives a spectral signal and a laser signal. The system further includes a wideband detector, which is in communication with the FTS spectrometer and receives the spectral signal and laser signal from the FTS spectrometer. The wideband detector produces a composite signal comprising the laser signal and the spectral signal. The system further comprises a converter in communication with the wideband detector to receive and digitize the composite signal. The system further includes a signal processing unit that receives the composite signal from the converter. The signal processing unit further filters the laser signal and the spectral signal from the composite signal and demodulates the laser signal, to produce velocity corrected spectral data.

Frequency shifts in stimulated Raman scattering

International Nuclear Information System (INIS)

Zinth, W.; Kaiser, W.

1980-01-01

The nonresonant contributions to the nonlinear susceptibility chisup(()3) produce a frequency chirp during stimulated Raman scattering. In the case of transient stimulated Raman scattering, the spectrum of the generated Stokes pulse is found at higher frequencies than expected from spontaneous Raman data. The frequency difference can be calculated from the theory of stimulated Raman scattering. (orig.)

Raman scattering tensors of tyrosine.

Science.gov (United States)

Tsuboi, M; Ezaki, Y; Aida, M; Suzuki, M; Yimit, A; Ushizawa, K; Ueda, T

1998-01-01

Polarized Raman scattering measurements have been made of a single crystal of L-tyrosine by the use of a Raman microscope with the 488.0-nm exciting beam from an argon ion laser. The L-tyrosine crystal belongs to the space group P2(1)2(1)2(1) (orthorhombic), and Raman scattering intensities corresponding to the aa, bb, cc, ab and ac components of the crystal Raman tensor have been determined for each prominent Raman band. A similar set of measurements has been made of L-tyrosine-d4, in which four hydrogen atoms on the benzene ring are replaced by deuterium atoms. The effects of NH3-->ND3 and OH-->OD on the Raman spectrum have also been examined. In addition, depolarization ratios of some bands of L-tyrosine in aqueous solutions of pH 13 and pH 1 were examined. For comparison with these experimental results, on the other hand, ab initio molecular orbital calculations have been made of the normal modes of vibration and their associated polarizability oscillations of the L-tyrosine molecule. On the basis of these experimental data and by referring to the results of the calculations, discussions have been presented on the Raman tensors associated to some Raman bands, including those at 829 cm-1 (benzene ring breathing), 642 cm-1 (benzene ring deformation), and 432 cm-1 (C alpha-C beta-C gamma bending).

X-ray microbeam measurements of long-range internal stresses in commercial-purity aluminum processed by multiple passes of equal-channel angular pressing

International Nuclear Information System (INIS)

Phan, Thien Q.; Lee, I-Fang; Levine, Lyle E.; Tischler, Jonathan Z.; Huang, Yi; Fox, Alan G.; Langdon, Terence G.; Kassner, Michael E.

2014-01-01

X-ray microbeam diffraction was used to measure long-range internal stresses (LRISs) in the grain/subgrain interiors of commercial-purity aluminum processed by equal-channel angular pressing for up to eight passes. The LRIS values at +4.9° off the axial (pressing) direction show only a slight increase with increasing numbers of passes. The normalized stress remains approximately constant at ∼0.10 of the flow stress

Establishing the suitability of quantitative optical CT microscopy of PRESAGE® radiochromic dosimeters for the verification of synchrotron microbeam therapy

Science.gov (United States)

Doran, Simon J.; Rahman, A. T. Abdul; Bräuer-Krisch, Elke; Brochard, Thierry; Adamovics, John; Nisbet, Andrew; Bradley, David

2013-09-01

Previous research on optical computed tomography (CT) microscopy in the context of the synchrotron microbeam has shown the potential of the technique and demonstrated high quality images, but has left two questions unanswered: (i) are the images suitably quantitative for 3D dosimetry? and (ii) what is the impact on the spatial resolution of the system of the limited depth-of-field of the microscope optics? Cuvette and imaging studies are reported here that address these issues. Two sets of cuvettes containing the radiochromic plastic PRESAGE® were irradiated at the ID17 biomedical beamline of the European Synchrotron Radiation facility over the ranges 0-20 and 0-35 Gy and a third set of cuvettes was irradiated over the range 0-20 Gy using a standard medical linac. In parallel, three cylindrical PRESAGE® samples of diameter 9.7 mm were irradiated with test patterns that allowed the quantitative capabilities of the optical CT microscope to be verified, and independent measurements of the imaging modulation transfer function (MTF) to be made via two different methods. Both spectrophotometric analysis and imaging gave a linear dose response, with gradients ranging from 0.036-0.041 cm-1 Gy-1 in the three sets of cuvettes and 0.037 (optical CT units) Gy-1 for the imaging. High-quality, quantitative imaging results were obtained throughout the 3D volume, as illustrated by depth-dose profiles. These profiles are shown to be monoexponential, and the linear attention coefficient of PRESAGE® for the synchrotron-generated x-ray beam is measured to be (0.185 ± 0.02) cm-1 in excellent agreement with expectations. Low-level (<5%) residual image artefacts are discussed in detail. It was possible to resolve easily slit patterns of width 37 µm (which are smaller than many of the microbeams used on ID-17), but some uncertainty remains as to whether the low values of MTF for the higher spatial frequencies are scanner related or a result of genuine (but non-ideal) dose

Digital positron annihilation spectrometer

International Nuclear Information System (INIS)

Cheng Bin; Weng Huimin; Han Rongdian; Ye Bangjiao

2010-01-01

With the high speed development of digital signal process, the technique of the digitization and processing of signals was applied in the domain of a broad class of nuclear technique. The development of digital positron lifetime spectrometer (DPLS) is more promising than the conventional positron lifetime spectrometer equipped with nuclear instrument modules. And digital lifetime spectrometer has many advantages, such as low noise, long term stability, flexible online or offline digital processing, simple setup, low expense, easy to setting, and more physical information. Digital constant fraction discrimination is for timing. And a new method of optimizing energy windows setting for digital positron lifetime spectrometer is also developed employing the simulated annealing for the convenient use. The time resolution is 220ps and the count rate is 200cps. (authors)

Difference Raman spectroscopy of DNA molecules

International Nuclear Information System (INIS)

Anokhin, Andrey S; Yuzyuk, Yury I; Gorelik, Vladimir S; Dovbeshko, Galina I; Pyatyshev, Alexander Yu

2015-01-01

In this paper the micro-Raman spectra of calf DNA for different points of DNA sample have been recorded. The Raman spectra were made with help of difference Raman spectroscopy technique. Raman spectra were recorded with high spatial resolution from different points of the wet and dry samples in different spectral range (100÷4000cm −1 ) using two lasers: argon (514.5 nm) and helium -neon (632.8 nm). The significant differences in the Raman spectra for dry and wet DNA and for different points of DNA molecules were observed. The obtained data on difference Raman scattering spectra of DNA molecules may be used for identification of DNA types and for analysis of genetic information associated with the molecular structure of this molecule

Surface-Enhanced Raman Spectroscopy

Indian Academy of Sciences (India)

IAS Admin

weak Raman signal, which facilitates identification in chemi- cal and biological systems. Recently, single-molecule Raman scattering has enhanced the detection sensitivity limit of ... was working on the molecular diffraction of light, which ulti-.

A comparison of ray-tracing software for the design of quadrupole microbeam systems

International Nuclear Information System (INIS)

Incerti, S.; Smith, R.W.; Merchant, M.; Grime, G.W.; Meot, F.; Serani, L.; Moretto, Ph.; Touzeau, C.; Barberet, Ph.; Habchi, C.; Nguyen, D.T.

2005-01-01

For many years the only ray-tracing software available with sufficient precision for the design of quadrupole microbeam focusing systems has been OXRAY and its successor TRAX, developed at Oxford in the 1980s. With the current interest in pushing the beam diameter into the nanometre region, this software has become dated and more importantly the precision at small displacements may not be sufficient and new simulation tools are required. Two candidates for this are Zgoubi, developed at CEA as a general beam line design tool and the CERN simulation program Geant in its latest version Geant4. In order to use Geant4 new quadrupole field modules have been developed and implemented. In this paper the capabilities of the three codes TRAX, Zgoubi and Geant4 are reviewed. Comparisons of ray-tracing calculations in a high demagnification quadrupole probe-forming system for the sub-micron region are presented

Surface-Enhanced Raman Spectroscopy

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 2. Surface-Enhanced Raman Spectroscopy - Recent Advancement of Raman Spectroscopy. Ujjal Kumar Sur. General Article Volume 15 Issue 2 February 2010 pp 154-164 ...

Application of Raman Microspectroscopic and Raman imaging techniques for cell biological studies

NARCIS (Netherlands)

Puppels, G.J.; Puppels, G.J.; Bakker schut, T.C.; Bakker Schut, T.C.; Sijtsema, N.M.; Grond, M.; Grond, M.; Maraboeuf, F.; de Grauw, C.J.; de Grauw, C.J.; Figdor, Carl; Greve, Jan

1995-01-01

Raman spectroscopy is being used to study biological molecules for some three decades now. Thanks to continuing advances in instrumentation more and more applications have become feasible in which molecules are studied in situ, and this has enabled Raman spectroscopy to enter the realms of

Femtosecond Broadband Stimulated Raman Spectroscopy

International Nuclear Information System (INIS)

Lee, Soo-Y; Yoon, Sagwoon; Mathies, Richard A

2006-01-01

Femtosecond broadband stimulated Raman spectroscopy (FSRS) is a new technique where a narrow bandwidth picosecond Raman pump pulse and a red-shifted broadband femtosecond Stokes probe pulse (with or without time delay between the pulses) act on a sample to produce a high resolution Raman gain spectrum with high efficiency and speed, free from fluorescence background interference. It can reveal vibrational structural information and dynamics of stationary or transient states. Here, the quantum picture for femtosecond broadband stimulated Raman spectroscopy (FSRS) is used to develop the semiclassical coupled wave theory of the phenomenon and to derive an expression for the measurable Raman gain in FSRS. The semiclassical theory is applied to study the dependence of lineshapes in FSRS on the pump-probe time delay and to deduce vibrational dephasing times in cyclohexane in the ground state

Design of an 1800nm Raman amplifier

DEFF Research Database (Denmark)

Svane, Ask Sebastian; Rottwitt, Karsten

2013-01-01

We present the experimental results for a Raman amplifier that operates at 1810 nm and is pumped by a Raman fiber laser at 1680 nm. Both the pump laser and the Raman amplifier is polarization maintaining. A challenge when scaling Raman amplifiers to longer wavelengths is the increase...... in transmission loss, but also the reduction in the Raman gain coefficient as the amplifier wavelength is increased. Both polarization components of the Raman gain is characterized, initially for linearly co-polarized signal and pump, subsequently linearly polarized orthogonal signal and pump. The noise...

Monolithic PM Raman fiber laser at 1679 nm for Raman amplification at 1810 nm

DEFF Research Database (Denmark)

Svane, Ask Sebastian; Rottwitt, Karsten

2013-01-01

Stimulated Raman scattering (SRS) has been subject to much attention within the field of fiber lasers and amplifiers as it provides an extended wavelength coverage in comparison to rare-earth based devices. Motivated by the projected capacity crunch [1], different approaches are being explored...... demonstrate a monolithic RM Raman fiber laser (RFL), which acts as a pump for a Raman amplifier (RA) at 1810 nm. The lasing wavelength of a RFL, thus also for a RA, can in principle be designed arbitrarily within the entire wavelength range from the Erbium band up to the Thulium/Holmium band...... of OFS PM Raman fiber, with an estimated propagation loss of 0.42/0.46/1.3 dB/km at 1564/1679/1810 nm. The Raman gain coefficient was measured to be gR=2.66/2.35 W-1km-1 at 1679/1810 nm. The laser curve of the RFL is depicted in Fig. 1b, with a slope efficiency of 67 %. The high slope efficiency...

Influence of a photoexcited electron-hole plasma on the Raman scattering spectra of YBa2Cu3Ox single crystals

International Nuclear Information System (INIS)

Goncharov, A.F.; Denisov, V.N.; Mavrin, B.N.; Podobedov, V.B.

1988-01-01

The Raman spectra of tetragonal YBa 2 Cu 3 O x crystals in the region of ∼500 cm -1 were determined using different power densities I 0 of the exciting radiation of wavelengths 4,880, 5,145, 5,321, and 6,471 angstrom at temperatures 80-300 K. An increase in I 0 revealed changes in the spectra due to interference of the electron continuum with a 470 cm -1 phonon and also due to activation of 560-590 cm -1 dipole vibrations because of interaction of photocarriers with the crystal lattice. An analysis of the spectra yielded the electron-phonon interaction constant. The changes in the spectra were of resonant nature, but they were absent in the case of the excitation wavelengths 5,321 and 6,471 angstrom. A triple multichannel Raman spectrometer, developed by the authors, made it possible to record simultaneously a spectral interval of 500 cm -1 in the range ≥ 25 cm -1 on excitation with cw laser radiation

Development of a miRNA surface-enhanced Raman scattering assay using benchtop and handheld Raman systems

Science.gov (United States)

Schechinger, Monika; Marks, Haley; Locke, Andrea; Choudhury, Mahua; Cote, Gerard

2018-01-01

DNA-functionalized nanoparticles, when paired with surface-enhanced Raman spectroscopy (SERS), can rapidly detect microRNA. However, widespread use of this approach is hindered by drawbacks associated with large and expensive benchtop Raman microscopes. MicroRNA-17 (miRNA-17) has emerged as a potential epigenetic indicator of preeclampsia, a condition that occurs during pregnancy. Biomarker detection using an SERS point-of-care device could enable prompt diagnosis and prevention as early as the first trimester. Recently, strides have been made in developing portable Raman systems for field applications. An SERS assay for miRNA-17 was assessed and translated from traditional benchtop Raman microscopes to a handheld system. Three different photoactive molecules were compared as potential Raman reporter molecules: a chromophore, malachite green isothiocyanate (MGITC), a fluorophore, tetramethylrhodamine isothiocyanate, and a polarizable small molecule 5,5-dithio-bis-(2-nitrobenzoic acid) (DTNB). For the benchtop Raman microscope, the DTNB-labeled assay yielded the greatest sensitivity under 532-nm laser excitation, but the MGITC-labeled assay prevailed at 785 nm. Conversely, DTNB was preferable for the miniaturized 785-nm Raman system. This comparison showed significant SERS enhancement variation in response to 1-nM miRNA-17, implying that the sensitivity of the assay may be more heavily dependent on the excitation wavelength, instrumentation, and Raman reporter chosen than on the plasmonic coupling from DNA/miRNA-mediated nanoparticle assemblies.

Raman spectra of graphene ribbons

International Nuclear Information System (INIS)

Saito, R; Furukawa, M; Dresselhaus, G; Dresselhaus, M S

2010-01-01

Raman spectra of graphene nanoribbons with zigzag and armchair edges are calculated within non-resonant Raman theory. Depending on the edge structure and polarization direction of the incident and scattered photon beam relative to the edge direction, a symmetry selection rule for the phonon type appears. These Raman selection rules will be useful for the identification of the edge structure of graphene nanoribbons.

Simulation of the SAGE spectrometer

Energy Technology Data Exchange (ETDEWEB)

Cox, D.M.; Herzberg, R.D. [University of Liverpool, Department of Physics, Oliver Lodge Laboratory, Liverpool (United Kingdom); Konki, J.; Greenlees, P.T.; Pakarinen, J.; Papadakis, P.; Rahkila, P.; Sandzelius, M.; Sorri, J. [University of Jyvaeskylae, Department of Physics, Jyvaeskylae (Finland); Hauschild, K. [Universite Paris-Sud, CSNSM-IN2P3-CNRS, Orsay (France)

2015-06-15

The SAGE spectrometer combines a Ge-detector array with a Si detector to allow simultaneous detection of γ-rays and electrons. A comprehensive GEANT4 simulation package of the SAGE spectrometer has been developed with the ability to simulate the expected datasets based on user input files. The measured performance of the spectrometer is compared to the results obtained from the simulations. (orig.)

Simulation of the SAGE spectrometer

International Nuclear Information System (INIS)

Cox, D.M.; Herzberg, R.D.; Konki, J.; Greenlees, P.T.; Pakarinen, J.; Papadakis, P.; Rahkila, P.; Sandzelius, M.; Sorri, J.; Hauschild, K.

2015-01-01

The SAGE spectrometer combines a Ge-detector array with a Si detector to allow simultaneous detection of γ-rays and electrons. A comprehensive GEANT4 simulation package of the SAGE spectrometer has been developed with the ability to simulate the expected datasets based on user input files. The measured performance of the spectrometer is compared to the results obtained from the simulations. (orig.)

Measurement and Simulation of Spontaneous Raman Scattering Spectra in High-Pressure, Fuel-Rich H2-Air Flames

Science.gov (United States)

Kojima, Jun; Nguyen, Quang-Viet

2003-01-01

Rotational vibrational spontaneous Raman spectra (SRS) of H2, N2, and H2O have been measured in H2-air flames at pressures up to 30 atm as a first stem towards establishing a comprehensive Raman spectral database for temperatures and species in high-pressure combustion. A newly developed high-pressure burner facility provides steady, reproducible flames with a high degree of flow precision. We have obtained an initial set of measurements that indicate the spectra are of sufficient quality in terms of spectral resolution, wavelength coverage, and signal-to-noise ratio for use in future reference standards. The fully resolved Stokes and anti-Stokes shifted SRS spectra were collected in the visible wavelength range (400-700 nm) using pulse-stretched 532 nm excitation and a non-intensified CCD spectrograph with a high-speed shutter. Reasonable temperatures were determined via the intensity distribution of rotational H2 lines at stoichiometry and fuel-rich conditions. Theoretical Raman spectra of H2 were computed using a semi-classical harmonic-oscillator model with recent pressure broadening data and were compared with experimental results. The data and simulation indicated that high-J rotational lines of H2 might interfere with the N2 vibrational Q-branch lines, and this could lead to errors in N2-Raman thermometry based on the line-fitting method. From a comparison of N2 Q-branch spectra in lean H2 low-pressure (1.2 atm) and high-pressure (30 atm) flames, we found no significant line-narrowing or -broadening effects at the current spectrometer resolution of 0.04 nm.

Raman spectroscopy in high temperature chemistry

International Nuclear Information System (INIS)

Drake, M.C.; Rosenblatt, G.M.

1979-01-01

Raman spectroscopy (largely because of advances in laser and detector technology) is assuming a rapidly expanding role in many areas of research. This paper reviews the contribution of Raman spectroscopy in high temperature chemistry including molecular spectroscopy on static systems and gas diagnostic measurements on reactive systems. An important aspect of high temperature chemistry has been the identification and study of the new, and often unusual, gaseous molecules which form at high temperatures. Particularly important is the investigation of vibrational-rotational energy levels and electronic states which determine thermodynamic properties and describe chemical bonding. Some advantages and disadvantages of high temperature Raman spectrosocpy for molecular studies on static systems are compared: (1) Raman vs infrared; (2) gas-phase vs condensed in matries; and (3) atmospheric pressure Raman vs low pressure techniques, including mass spectroscopy, matrix isolation, and molecular beams. Raman studies on molecular properties of gases, melts, and surfaces are presented with emphasis on work not covered in previous reviews of high temperature and matrix isolation Raman spectroscopy

Raman spectroscopy in high temperature chemistry

International Nuclear Information System (INIS)

Drake, M.C.; Rosenblatt, G.M.

1979-01-01

Raman spectroscopy (largely because of advances in laser and detector technology) is assuming a rapidly expanding role in many areas of research. This paper reviews the contribution of Raman spectroscopy in high temperature chemistry including molecular spectroscopy on static systems and gas diagnostic measurements on reactive systems. An important aspect of high temperature chemistry has been the identification and study of the new, and often unusual, gaseous molecules which form at high temperatures. Particularly important is the investigation of vibrational-rotational energy levels and electronic states which determine thermodynamic properties and describe chemical bonding. Some advantages and disadvantages of high temperature Raman spectrosocpy for molecular studies on static systems are compared: (1) Raman vs infrared; (2) gas-phase vs condensed in matrices; and (3) atmospheric pressure Raman vs low pressure techniques, including mass spectroscopy, matrix isolation, and molecular beams. Raman studies on molecular properties of gases, melts, and surfaces are presented with emphasis on work not covered in previous reviews of high temperature and matrix isolation Raman spectroscopy

Dynamics of an Imperfect Microbeam Considering its Exact Shape

KAUST Repository

Bataineh, Ahmad M.

2014-08-17

We study the static and dynamic behavior of electrically actuated micromachined arches. First, we conduct experiments on micromachined polysilicon beams by driving them electrically and varying their amplitude and frequency of voltage loads. The results reveal several interesting nonlinear phenomena of jumps, hysteresis, and softening behaviors. Next, we conduct analytical and theoretical investigation to understand the experiments. First, we solve the Eigen value problem analytically. We study the effect of the initial rise on the natural frequency and mode shapes, and use a Galerkin-based procedure to derive a reduced order model, which is then used to solve both the static and dynamic responses. We use two symmetric modes in the reduced order model to have accurate and converged results. We use long time integration to solve the nonlinear ordinary differential equations, and then modify our model using effective length to match experimental results. To further improve the matching with the experimental data, we curve-fit the exact profile of the microbeam to match the experimentally measured profile and use it in the reduced-order model to generate frequency-response curves. Finally, we use another numerical technique, the shooting technique, to solve the nonlinear ordinary differential equations. By using shooting and the curve fitted function, we found that we get good agreement with the experimental data.

Ultrafast surface-enhanced Raman spectroscopy.

Science.gov (United States)

Keller, Emily L; Brandt, Nathaniel C; Cassabaum, Alyssa A; Frontiera, Renee R

2015-08-07

Ultrafast surface-enhanced Raman spectroscopy (SERS) with pico- and femtosecond time resolution has the ability to elucidate the mechanisms by which plasmons mediate chemical reactions. Here we review three important technological advances in these new methodologies, and discuss their prospects for applications in areas including plasmon-induced chemistry and sensing at very low limits of detection. Surface enhancement, arising from plasmonic materials, has been successfully incorporated with stimulated Raman techniques such as femtosecond stimulated Raman spectroscopy (FSRS) and coherent anti-Stokes Raman spectroscopy (CARS). These techniques are capable of time-resolved measurement on the femtosecond and picosecond time scale and can be used to follow the dynamics of molecules reacting near plasmonic surfaces. We discuss the potential application of ultrafast SERS techniques to probe plasmon-mediated processes, such as H2 dissociation and solar steam production. Additionally, we discuss the possibilities for high sensitivity SERS sensing using these stimulated Raman spectroscopies.

Blood analysis by Raman spectroscopy.

Science.gov (United States)

Enejder, Annika M K; Koo, Tae-Woong; Oh, Jeankun; Hunter, Martin; Sasic, Slobodan; Feld, Michael S; Horowitz, Gary L

2002-11-15

Concentrations of multiple analytes were simultaneously measured in whole blood with clinical accuracy, without sample processing, using near-infrared Raman spectroscopy. Spectra were acquired with an instrument employing nonimaging optics, designed using Monte Carlo simulations of the influence of light-scattering-absorbing blood cells on the excitation and emission of Raman light in turbid medium. Raman spectra were collected from whole blood drawn from 31 individuals. Quantitative predictions of glucose, urea, total protein, albumin, triglycerides, hematocrit, and hemoglobin were made by means of partial least-squares (PLS) analysis with clinically relevant precision (r(2) values >0.93). The similarity of the features of the PLS calibration spectra to those of the respective analyte spectra illustrates that the predictions are based on molecular information carried by the Raman light. This demonstrates the feasibility of using Raman spectroscopy for quantitative measurements of biomolecular contents in highly light-scattering and absorbing media.

Measurement of the surface-enhanced coherent anti-Stokes Raman scattering (SECARS) due to the 1574 cm(-1) surface-enhanced Raman scattering (SERS) mode of benzenethiol using low-power (CW diode lasers.

Science.gov (United States)

Aggarwal, Roshan L; Farrar, Lewis W; Greeneltch, Nathan G; Van Duyne, Richard P; Polla, Dennis L

2013-02-01

The surface-enhanced coherent anti-Stokes Raman scattering (SECARS) from a self-assembled monolayer (SAM) of benzenethiol on a silver-coated surface-enhanced Raman scattering (SERS) substrate has been measured for the 1574 cm(-1) SERS mode. A value of 9.6 ± 1.7×10(-14) W was determined for the resonant component of the SECARS signal using 17.8 mW of 784.9 nm pump laser power and 7.1 mW of 895.5 nm Stokes laser power; the pump and Stokes lasers were polarized parallel to each other but perpendicular to the grooves of the diffraction grating in the spectrometer. The measured value of resonant component of the SECARS signal is in agreement with the calculated value of 9.3×10(-14) W using the measured value of 8.7 ± 0.5 cm(-1) for the SERS linewidth Γ (full width at half-maximum) and the value of 5.7 ± 1.4×10(-7) for the product of the Raman cross section σSERS and the surface concentration Ns of the benzenethiol SAM. The xxxx component of the resonant part of the third-order nonlinear optical susceptibility |3 χxxxx((3)R)| for the 1574 cm(-1) SERS mode has been determined to be 4.3 ± 1.1×10(-5) cm·g(-1)·s(2). The SERS enhancement factor for the 1574 cm(-1) mode was determined to be 3.6 ± 0.9×10(7) using the value of 1.8×10(15) molecules/cm(2) for Ns.

In vivo analysis of tissue by Raman microprobe: examination of human skin lesions and esophagus Barrett's mucosa on an animal model

Science.gov (United States)

Tfayli, Ali; Piot, Olivier; Derancourt, Sylvie; Cadiot, Guillaume; Diebold, Marie D.; Bernard, Philippe; Manfait, Michel

2006-02-01

In the last few years, Raman spectroscopy has been increasingly used for the characterization of normal and pathological tissues. A new Raman system, constituted of optic fibers bundle coupled to an axial Raman spectrometer (Horiba Jobin Yvon SAS), was developed for in vivo investigations. Here, we present in vivo analysis on two tissues: human skin and esophagus mucosa on a rat model. The skin is a directly accessible organ, representing a high diversity of lesions and cancers. Including malignant melanoma, basal cell carcinoma and the squamous cell carcinoma, skin cancer is the cancer with the highest incidence worldwide. Several Raman investigations were performed to discriminate and classify different types of skin lesions, on thin sections of biopsies. Here, we try to characterize in vivo the different types of skin cancers in order to be able to detect them in their early stages of development and to define precisely the exeresis limits. Barrett's mucosa was also studied by in vivo examination of rat's esophagus. Barrett's mucosa, induced by gastro-esophageal reflux, is a pretumoral state that has to be carefully monitored due to its high risk of evolution in adenocarcinoma. A better knowledge of the histological transformation of esophagus epithelium in a Barrett's type will lead to a more efficient detection of the pathology for its early diagnosis. To study these changes, an animal model (rats developing Barrett's mucosa after duodenum - esophagus anastomosis) was used. Potential of vibrational spectroscopy for Barrett's mucosa identification is assessed on this model.

Development of a miRNA surface-enhanced Raman scattering assay using benchtop and handheld Raman systems.

Science.gov (United States)

Schechinger, Monika; Marks, Haley; Locke, Andrea; Choudhury, Mahua; Cote, Gerard

2018-01-01

DNA-functionalized nanoparticles, when paired with surface-enhanced Raman spectroscopy (SERS), can rapidly detect microRNA. However, widespread use of this approach is hindered by drawbacks associated with large and expensive benchtop Raman microscopes. MicroRNA-17 (miRNA-17) has emerged as a potential epigenetic indicator of preeclampsia, a condition that occurs during pregnancy. Biomarker detection using an SERS point-of-care device could enable prompt diagnosis and prevention as early as the first trimester. Recently, strides have been made in developing portable Raman systems for field applications. An SERS assay for miRNA-17 was assessed and translated from traditional benchtop Raman microscopes to a handheld system. Three different photoactive molecules were compared as potential Raman reporter molecules: a chromophore, malachite green isothiocyanate (MGITC), a fluorophore, tetramethylrhodamine isothiocyanate, and a polarizable small molecule 5,5-dithio-bis-(2-nitrobenzoic acid) (DTNB). For the benchtop Raman microscope, the DTNB-labeled assay yielded the greatest sensitivity under 532-nm laser excitation, but the MGITC-labeled assay prevailed at 785 nm. Conversely, DTNB was preferable for the miniaturized 785-nm Raman system. This comparison showed significant SERS enhancement variation in response to 1-nM miRNA-17, implying that the sensitivity of the assay may be more heavily dependent on the excitation wavelength, instrumentation, and Raman reporter chosen than on the plasmonic coupling from DNA/miRNA-mediated nanoparticle assemblies. (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

All-Fiber Raman Probe

DEFF Research Database (Denmark)

Brunetti, Anna Chiara

by means of fiber components. Assuming the possibility to use a fiber laser with a fundamental radiation at 1064nm, in-fiber efficient second harmonic generation is achieved by optically poling the core of the waveguide delivering the excitation light to the sample. In this way, Raman spectroscopy...... in the visible range can be performed. The simultaneous delivery of the excitation light and collection of the Raman signal from the sample are achieved by means of a doubleclad fiber, whose core and inner cladding act as \\independent" transmission channels. A double-clad fiber coupler allows for the recovery...... of the collected Raman scattering from the inner-cladding region of the double-clad fiber, thus replacing the bulk dichroic component normally used to demultiplex the pump and Raman signal. A tunable Rayleigh-rejection filter based on a liquid filled-photonic bandgap fiber is also demonstrated in this work...

FT-Raman spectroscopic study of bayerite, boehmite, diaspore and gibbsite

International Nuclear Information System (INIS)

Ruan, H.D.; Frost, R.L.; Kloprogge, J.T.

1998-01-01

Full text: Bayerite and gibbsite are alumina trihydrate (Al(OH) 3 ). Gibbsite occurs abundantly in nature, usually as a major mineral component in bauxite whereas bayerite is rarely found in nature. Boehmite and diaspore are alumina oxohydroxide (AlOOH) and are two other important minerals in bauxite. The Raman spectra of these four minerals were obtained using a Fourier transform Raman spectrometer operating at 1064 nm. The spectra can be divided into two regions, the low frequency region from 200 to 1200 cm -1 and the hydroxyl stretching region from 3000 to 3700 cm -1 . Bayerite spectrum shows five absorption bands, 3652, 3542, 3449, 3438, and 3421 cm -1 and the gibbsite spectrum shows four strong and sharp absorption bands, 3619, 3523, 3433 and 3363 cm -1 in the hydroxyl stretching region. These values are consistent with those reported by Huneke et al. (1980) and Frost et al. (1999a). Four broad bands, 3426, 3365, 3229 and 2935 cm -1 and three weak bands, 3420, 3216 and 3090 cm -1 are present in this region for diaspore and boehmite. The Raman bands correspond well with the infrared absorption bands at 3620, 3525 cm -1 for gibbsite, 3365 cm -1 for diaspore and 3423, 3096 cm -1 for boehmite (Frost et al., 1999c) and these bands are assigned to be Raman and infrared active. The spectra of bayerite, gibbsite and diaspore are complex while the spectrum of boehmite only illustrates four absorption bands in the low frequency region. Common bands of RT-Raman spectra at 1019, 892, 816, 710, 568, 539, 506, 429, 395, 379, 21, 306, 255 and 242 cm -1 were observed for gibbsite, 1079,1068, 898, 866, 545, 434, 388, 322, 292, 250 and 239 cm -1 for bayerite, 705, 608, 446, 260 and 216 cm -1 for diaspore, and 674, 495 and 360 cm -1 for boehmite. The differences in the vibrational spectra of bayerite, gibbsite, diaspore and boehmite are due to differences in the molecular structure of these minerals. The 705, 446 and 260 cm -1 bands are the most intense in the Raman spectra of

Raman amplification in optical communication systems

DEFF Research Database (Denmark)

Kjær, Rasmus

2008-01-01

Fiber Raman amplifiers are investigated with the purpose of identifying new applications and limitations for their use in optical communication systems. Three main topics are investigated, namely: New applications of dispersion compensating Raman amplifiers, the use Raman amplification to increase...... fiberbaserede Raman-forstærkere med henblik på at identificere både deres begrænsninger og nye anvendelsesmuligheder i optiske kommunikationssystemer. En numerisk forstærkermodel er blevet udviklet for bedre at forstå forstærkerens dynamik, dens gain- og støjbegrænsninger. Modellen bruges til at forudsige...... forstærkerens statiske og dynamiske egenskaber, og det eftervises at dens resultater er i god overensstemmelse med eksperimentelle forstærkermålinger. Dispersions-kompenserende fiber er på grund af sin store udbredelse og fiberens høje Raman gain effektivitet et meget velegnet Raman gain-medium. Tre nye...

The MEG positron spectrometer

International Nuclear Information System (INIS)

Nishiguchi, Hajime

2007-01-01

We have been developing an innovative spectrometer for the MEG experiment at the Paul Scherrer Institute (PSI) in Switzerland. This experiment searches for a lepton flavour violating decay μ + →e + γ with a sensitivity of 10 -13 in order to explore the region predicted by supersymmetric extensions of the standard model. The MEG positron spectrometer consists of a specially designed superconducting solenoidal magnet with a highly graded field, an ultimate low-mass drift chamber system, and a precise time measuring counter system. This innovative positron spectrometer is described here focusing on the drift chamber system

VEGAS: VErsatile GBT Astronomical Spectrometer

Science.gov (United States)

Bussa, Srikanth; VEGAS Development Team

2012-01-01

The National Science Foundation Advanced Technologies and Instrumentation (NSF-ATI) program is funding a new spectrometer backend for the Green Bank Telescope (GBT). This spectrometer is being built by the CICADA collaboration - collaboration between the National Radio Astronomy Observatory (NRAO) and the Center for Astronomy Signal Processing and Electronics Research (CASPER) at the University of California Berkeley.The backend is named as VErsatile GBT Astronomical Spectrometer (VEGAS) and will replace the capabilities of the existing spectrometers. This backend supports data processing from focal plane array systems. The spectrometer will be capable of processing up to 1.25 GHz bandwidth from 8 dual polarized beams or a bandwidth up to 10 GHz from a dual polarized beam.The spectrometer will be using 8-bit analog to digital converters (ADC), which gives a better dynamic range than existing GBT spectrometers. There will be 8 tunable digital sub-bands within the 1.25 GHz bandwidth, which will enhance the capability of simultaneous observation of multiple spectral transitions. The maximum spectral dump rate to disk will be about 0.5 msec. The vastly enhanced backend capabilities will support several science projects with the GBT. The projects include mapping temperature and density structure of molecular clouds; searches for organic molecules in the interstellar medium; determination of the fundamental constants of our evolving Universe; red-shifted spectral features from galaxies across cosmic time and survey for pulsars in the extreme gravitational environment of the Galactic Center.

DC dynamic pull-in predictions for a generalized clamped–clamped micro-beam based on a continuous model and bifurcation analysis

International Nuclear Information System (INIS)

Chao, Paul C-P; Chiu, C W; Liu, Tsu-Hsien

2008-01-01

This study is devoted to providing precise predictions of the dc dynamic pull-in voltages of a clamped–clamped micro-beam based on a continuous model. A pull-in phenomenon occurs when the electrostatic force on the micro-beam exceeds the elastic restoring force exerted by beam deformation, leading to contact between the actuated beam and bottom electrode. DC dynamic pull-in means that an instantaneous application of the voltage (a step function such as voltage) is applied. To derive the pull-in voltage, a dynamic model in partial differential equations is established based on the equilibrium among beam flexibility, inertia, residual stress, squeeze film, distributed electrostatic forces and its electrical field fringing effects. The method of Galerkin decomposition is then employed to convert the established system equations into reduced discrete modal equations. Considering lower-order modes and approximating the beam deflection by a different order series, bifurcation based on phase portraits is conducted to derive static and dynamic pull-in voltages. It is found that the static pull-in phenomenon follows dynamic instabilities, and the dc dynamic pull-in voltage is around 91–92% of the static counterpart. However, the derived dynamic pull-in voltage is found to be dependent on the varied beam parameters, different from a fixed predicted value derived in past works, where only lumped models are assumed. Furthermore, accurate closed-form predictions are provided for non-narrow beams. The predictions are finally validated by finite element analysis and available experimental data

Surface-enhanced Raman detection of RNA and DNA bases following flow-injection analysis or HPLC separation

Science.gov (United States)

Cotton, Therese M.; Sheng, Rong-Sheng; Ni, Fan