Name: applying x-ray imaging crystal spectroscopy for use as a high temperature plasma diagnostic
Uploaded: 2016-08-25T13:00:00.000+00:00
Duration: 6 min 46 s
Description: Watch this Scientific Journal Video about Applying X-ray Imaging Crystal Spectroscopy for Use as a High Temperature Plasma Diagnostic at JoVE.com

The authors would like to thank Matt Reinke and the Alcator C-Mod team for designing, building, and testing HIREXSR. This work was supported by DOE Contract Nos. DE-FC02-99ER54512 and DE-AC02-76CH03073.

<ol>
	<li>Reinke, M. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=X-ray+imaging+crystal+spectroscopy+for+use+in+plasma+transport+research.">X-ray imaging crystal spectroscopy for use in plasma transport research.</a> Rev. Sci. Instrum. 83 (11), 113504 (2012).</li><li>Hill, K. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+High+Resolution+X-Ray+Imaging+Crystal+Spectrometer+for+Measurement+of+Ion-Temperature+and+Rotation-Velocity+Profiles+in+Fusion+Energy+Research+Plasmas.">Development of a High Resolution X-Ray Imaging Crystal Spectrometer for Measurement of Ion-Temperature and Rotation-Velocity Profiles in Fusion Energy Research Plasmas.</a> Plasma Fusion Res. 2, 1067-1067 (2007).</li><li>Greenwald, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=20+years+of+research+on+the+Alcator+C-Mod+tokamak.">20 years of research on the Alcator C-Mod tokamak.</a> Phys. Plasmas. 21 (11), 110501 (2014).</li><li>Rice, J. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=X-ray+observations+of+medium+Z+H-+and+He-like+ions+with+satellites+from+C-Mod+tokamak+plasmas.">X-ray observations of medium Z H- and He-like ions with satellites from C-Mod tokamak plasmas.</a> J. Phys. B. 48 (14), 144013 (2015).</li><li>Ince-Cushman, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rotation+studies+in+fusion+plasmas+via+imaging+X-ray+crystal+spectroscopy.">Rotation studies in fusion plasmas via imaging X-ray crystal spectroscopy.</a> Rev. Sci. Instrum. 79, (2008).</li><li>Zachariasen, W. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Theory of X-Ray Diffraction in Crystals. , (2004).</li><li>Johann, H. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Die+Erzeugung+lichtstarker+R&#246;ntgenspektren+mit+Hilfe+von+Konkavkristallen.">Die Erzeugung lichtstarker R&#246;ntgenspektren mit Hilfe von Konkavkristallen.</a> Zeitschrift f&#252;r Physik. 69 (3-4), 185-206 (1931).</li><li>Wang, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calculation+of+the+Johann+error+for+spherically+bent+x-ray+imaging+crystal+spectrometers.">Calculation of the Johann error for spherically bent x-ray imaging crystal spectrometers.</a> Rev. Sci. Instrum. 81 (10), (2010).</li><li>Eikenberry, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PILATUS:+a+two-dimensional+X-ray+detector+for+macromolecular+crystallography.">PILATUS: a two-dimensional X-ray detector for macromolecular crystallography.</a> Nucl. Instr. Meth. Phys. Res. A. 501 (1), 260-266 (2003).</li><li>Howard, N. T., Greenwald, M., Rice, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+impurity+confinement+on+Alcator+C-Mod+using+a+multi-pulse+laser+blow-off+system.">Characterization of impurity confinement on Alcator C-Mod using a multi-pulse laser blow-off system.</a> Rev. Sci. Instrum. 82 (3), 1-6 (2011).</li><li>Rice, J. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Non-local+heat+transport,+rotation+reversals+and+up/down+impurity+density+asymmetries+in+Alcator+C-Mod+ohmic+L-mode+plasmas.">Non-local heat transport, rotation reversals and up/down impurity density asymmetries in Alcator C-Mod ohmic L-mode plasmas.</a> Nucl. Fusion. 53, 033004 (2013).</li><li>Reinke, M. L., Podpaly, Y., Gao, C., Science, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Operation and Validation of The HIREXSR Analysis COde MIT-Plasma Science and Fusion Center Alcator C-Mod. , (2013).</li><li>Rosen, A. S., Reinke, M. L., Rice, J. E., Hubbard, A. E., Hughes, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Validation+of+x-ray+line+ratios+for+electron+temperature+determination+in+tokamak+plasmas.">Validation of x-ray line ratios for electron temperature determination in tokamak plasmas.</a> J. Phys. B. 47 (10), 105701 (2014).</li><li>Delgado-Aparicio, L. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In-situ+wavelength+calibration+and+temperature+control+for+the+C-Mod+high-resolution+X-ray+crystal+imaging+spectrometer.">In-situ wavelength calibration and temperature control for the C-Mod high-resolution X-ray crystal imaging spectrometer.</a> Bull. Am. Phys. Soc. 55, (2010).</li></ol>

The authors have nothing to disclose.

この技術によって生成されたデータは、実験的研究の広範囲で使用することができます。イオン温度とトロイダル速度プロファイルは、本質的な自己生成プラズマ回転と非局所摂動効果を含む輸送研究の広い範囲で使用することができます。ハワードら。2011年10で行われていたように、レーザブローオフを通して注入した不純物のスペクトルを測定することも、血漿中の不純?...

X線スペクトルは、高温プラズマに関する豊富な情報を提供すること。例えば、電子温度と密度は、線強度比から推測することができます。軸外プラズマ表示ヨハン分光計を使用することにより、このような良好な空間及び時間分解能1,2プラズマ内部の密度、温度、及び速度などのプラズマパラメータのプロファイルを構築することが可能です。この原稿は、空間分解能（HIREXSR）、トカマク中の培地原子番号の元素の水素 - 及びヘリウム様イオンを表示するために使用される高波長分解能、空間的にイメージングX線分光器で高分解能X線結晶撮像分光装置の動作を提示しますプラズマ。 HIREXSRはAlcator C-Modの、それぞれ0.67メートルと0.22メートルのメジャーとマイナーの半径のトカマク核融合装置に配備されています。それは、典型的には、重水素プラズマが0.2から8.0×10 20メートルの間の平均密度で〜2秒の持続で動作-3 </su1-9 keVの3の間のp&gt;と中央の電子温度。これらの条件下では、高Z不純物元素の媒体は非常にイオン化し、対策をHIREXSR X線領域で放射します。よく診断された実験室プラズマから得られたX線スペクトルの原子コード・モデリングをベンチマークすると、他の独立した診断が4使用できない場合にプラズマパラメータを決定するために、このようなスペクトルの使用を正当化することが重要です。 すべての分光計は、その所望の使用のために構築されています。したがって、マシンとその関連する概念についての一般的な説明は完全にこれらの強力なツール5を把握することが必要です。光子が結晶の隣接する層を反射し、その波長の倍数である距離を走行する際、ブラッグ反射が発生します。1は、この現象を示している図 。この条件は、nは 、再オーダーである式のnλ= 2 Dの罪θbと表されます屈曲は、λは、光子の波長であり、dは結晶とθBの隣接する層の間の分離はブラッグ角です。 λとθbとの 1対1の対応は、同じ波長で検出器平面の旅行の特定の時点での全フォトンことを示しています。しかし、実際には、ブラッグ角からの偏差として現れる吸収と精度の限界。これは、ロッキングカーブ6で示される重要な建設的干渉を生成する角度だけ小さな範囲になる。 図2は、方解石結晶の例曲線です。 HIREXSRは球状に曲がっ結晶7とヨハン分光計です。この種の装置を説明する前に、簡単な、円形分光計の議論は適切です。これは、セットアップに角、それぞれのブラッグで入ってくる光子を反映して曲がった結晶で構成されてい病棟単一X線光子計数ピクセル検出器のアレイを。 図3に表示されているように結晶と検出器は、ローランド円の接線を置く。ローランド円の直径が結晶の曲率半径に等しいです。結晶の任意の点までの円周上の任意の点からの全ての光線は、結晶自体に関して同じ入射角を持っています。 HIREXSRの場合には、球状に曲がった結晶は、図4に示した子午面における空間分解能を可能にする子午線フォーカスF mは次のように定義されます。R cはの曲率半径メートル = R Cの罪θのB、F結晶。 - メートル / COS 2θbの F S = F：矢状焦点F Sは以下のように定義されます。分光計Δxの空間分解能が与えられます。によって： <img alt="方程式" src="/files/ftp_upload/54408/54408eq_DELTA_x.jpg" />ここで、L CPは結晶とプラズマとの間の距離であり、Dは、結晶の高さです。結晶層の2次元の間隔が離散的であるため、材料を選択する際に、これが考慮に入れなければなりません。検出器面は平面であるので、それらは、検出された光がローランド円上の対応する点上に正確に着弾されないので、結果的にエラーを生じさせる一点、でローランド円に接することができます。物理的には、この位置ずれは、検出器上の特定のエネルギーの光子の「にじみ」として現れます。このヨハン・エラーは以下のように定義されます<img alt="方程式" src="/files/ftp_upload/54408/54408eq_delta_xj.jpg" />ここで、lは 、結晶の幅です。検出器画素幅ΔXpはヨハン誤差よりもはるかに大きい場合、スペクトル分解能は、それとは無関係です。彼らの場合匹敵するサイズの再し、総誤差は、以下によって近似することができます。 <img alt="方程式" src="/files/ftp_upload/54408/54408eq_delta_x_2.jpg" /> 。結晶分光器の分解能は、次式で与えられます。 <img alt="方程式" src="/files/ftp_upload/54408/54408eq_lambda0.jpg" />ここで、 <img alt="方程式" src="/files/ftp_upload/54408/54408eq_delta_theta.jpg" /> 。 図5に示すように、代わりにHIREXSRに、しかし、ローランド円上の点に検出器の接線を置くの検出器は、スペクトル範囲のために精度を犠牲にするためにわずかに傾斜している。このエラーの分析は、実験的に確認されていると期待8に準拠しています。 ヨハン分光計を設計する際に考慮すべき2の重要なパラメータがあります。まず、撮像範囲は、分光計が観測されるかを決定します。プラズマを研究するために、ポロイダルとtoroiによって引き起こされるラインシフトを区別するために、その全体の断面を表示することが非常に望ましいですダル回転。 HIREXSRは、それが全体のプラズマを閲覧することができるように取り付けられており、正確なトロイダル測定を可能にするために（ 図6に示す）~8°の軸外に少し傾いています。第二に、時間分解能は、分光計が記録することができ、イベント間の最小時間を調節します。 Alcator C-Modのために、望ましい値は、エネルギーと粒子閉じ込め時​​間より短い20秒、以下です。 HIREXSR用途が20ミリ秒以上の6の時間分解能をサポートすることができ、X線計測ピクセル検出器は、9。 表1は、モジュールの仕様のすべてをまとめました。 摂動プラズマ研究のために、Alcator C-MODにレーザブローオフシステムは、正確なタイミング10と、複数のアブレーションを送達するために使用されます。レーザのNdである：YAG（ネオジムドープイットリウムアルミニウムガーネット）は、最大10Hzで動作します。レーザーは図7に示すように焦点を合わせ、リモート制御光学トレインに入射し、去勢牛スライド上の所望の位置にビーム。レーザーのスポットサイズは​​、注入は、プラズマを破壊しないように制御する必要があります。長焦点距離（1146ミリメートル）集光レンズは、アブレーションされたスポットサイズは​​、約0.5から7ミリメートルまで変化することを可能にするリモート制御リニアステージを介して光軸に沿って平行移動されます。高速ビームステアリングは、2D圧電ミラーを介して達成されます。この圧電システムは、ミラーができるマウント駆動RS232に装着されています。 Ndに加えて：YAGレーザー、633nmのダイオードレーザは、主（赤外線）ビームの位置を示すために使用されます。ビームは、第1のミラーを介して同一直線上にするように作られています。

<table><tbody><tr><td>PILATUS 100k Detector System</td><td>DECTRIS</td><td>100k</td><td>Superseded by newer PILATUS3 detectors</td></tr><tr><td>Bragg Crystals</td><td>Kurchaov Institute</td><td>Custom Part</td><td></td></tr><tr><td>CaF&lt;sub&gt;2&lt;/sub&gt; Slides</td><td>LeBow</td><td>Custom Part</td><td></td></tr><tr><td>High Purity Argon</td><td>Airgas</td><td>AR HP300</td><td>Any high purity argon should work</td></tr><tr><td>Be window</td><td>Brush Wellman Electrofusion Products / Motion Hightech</td><td>Custom part</td><td></td></tr></tbody></table>

applying x-ray imaging crystal spectroscopy for use as a high temperature plasma diagnostic

X線スペクトルは、高温プラズマに関する豊富な情報を提供すること。例えば、電子温度と密度は、線強度比から推測することができます。プラズマ表示ヨハン分光計を用いることにより、良好な空間及び時間分解能での密度、温度、及び速度などのプラズマパラメータのプロファイルを構築することが可能です。しかし、よく診断実験室プラズマから得られたX線スペクトルの原子コード・モデリングをベンチマークすると、他の独立した診断が利用できないときにプラズマパラメータを決定するために、このようなスペクトルの使用を正当化することが重要です。この原稿は、空間分解能（HIREXSR）、トカマク中の培地原子番号の元素の水素 - 及びヘリウム様イオンを表示するために使用される高波長分解能、空間的にイメージングX線分光器で高分解能X線結晶撮像分光装置の動作を提示しますプラズマ。また、この原稿は、そのようなイオンを導入することができ、レーザブローオフシステムをカバー正確なタイミングでプラズマにプラズマ中の輸送の摂動の研究を可能にします。

彼のようなアルゴンスペクトルのための1つの時間ビンのピクセル検出器からの代表的なデータサンプルは、図17に示されている。球状結晶によって楕円形状に曲げられたスペクトル線を、はっきりと見えます。トップ検出器が壊れた検出器パネルを持っており、検出器のすべてに散らばっていくつかのデッドピクセルがあります。壊れた検出器パネルか?...

Watch this Scientific Journal Video about Applying X-ray Imaging Crystal Spectroscopy for Use as a High Temperature Plasma Diagnostic at JoVE.com

Applying X-ray Imaging Crystal Spectroscopy for Use as a High Temperature Plasma Diagnostic

X線スペクトルは、高温プラズマに関する豊富な情報を提供しています。本稿では、空間的にトカマクプラズマ中の培地原子番号の元素の水素 - 及びヘリウム様イオンを表示するために使用されるX線分光器を画像化、高波長分解能の動作を示します。

高温プラズマ診断として使用するためのX線イメージングクリスタル分光法を適用します

X-ray spectra provide a wealth of information on high temperature plasmas; for example electron temperature and density can be inferred from line ...

applying-x-ray-imaging-crystal-spectroscopy-for-use-as-high

Universidad San Sebastian

Research

JoVE Journal

Engineering

11.3K ビュー.  Massachusetts Institute of Technology.  X線スペクトルは、高温プラズマに関する豊富な情報を提供しています。本稿では、空間的にトカマクプラズマ中の培地原子番号の元素の水素 - 及びヘリウム様イオンを表示するために使用されるX線分光器を画像化、高波長分解能の動作を示します。 

ビデオ: Applying X-ray Imaging Crystal Spectroscopy for Use as a High Temperature Plasma Diagnostic

Investigation of Early Plasma Evolution Induced by Ultrashort Laser Pulses

Early plasma is generated owing to high intensity laser irradiation of target and the subsequent target material ionization. Its dynamics plays a significant role in laser-material interaction, especially in the air environment1-11.
Early plasma evolution has been captured through pump-probe shadowgraphy1-3 and interferometry1,4-7. However, the studied time frames and applied laser parameter ranges are limited. For example, direct examinations of plasma front locations and electron number densities within a delay time of 100 picosecond (ps) with respect to the laser pulse peak are still very few, especially for the ultrashort pulse of a duration around 100 femtosecond (fs) and a low power density around 1014 W/cm2. Early plasma generated under these conditions has only been captured recently with high temporal and spatial resolutions12. The detailed setup strategy and procedures of this high precision measurement will be illustrated in this paper. The rationale of the measurement is optical pump-probe shadowgraphy: one ultrashort laser pulse is split to a pump pulse and a probe pulse, while the delay time between them can be adjusted by changing their beam path lengths. The pump pulse ablates the target and generates the early plasma, and the probe pulse propagates through the plasma region and detects the non-uniformity of electron number density. In addition, animations are generated using the calculated results from the simulation model of Ref. 12 to illustrate the plasma formation and evolution with a very high resolution (0.04 ~ 1 ps).
Both the experimental method and the simulation method can be applied to a broad range of time frames and laser parameters. These methods can be used to examine the early plasma generated not only from metals, but also from semiconductors and insulators.

An experimental method to examine the early plasma evolution induced by ultrashort laser pulses is described. Using this method, high quality images of early plasma are obtained with high temporal and spatial resolutions. A novel integrated atomistic model is used to simulate and explain the mechanisms of early plasma.

超短レーザーパルスにより誘起された初期プラズマの進化の解明

Early plasma is generated owing to high intensity laser irradiation of target and the subsequent target material ionization. Its dynamics plays a ...

工学

Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures

The physical properties of a material are defined by its electronic structure. Electrons in solids are characterized by energy (&omega;) and momentum (k) and the probability to find them in a particular state with given &omega; and k is described by the spectral function A(k, &omega;). This function can be directly measured in an experiment based on the well-known photoelectric effect, for the explanation of which Albert Einstein received the Nobel Prize back in 1921. In the photoelectric effect the light shone on a surface ejects electrons from the material. According to Einstein, energy conservation allows one to determine the energy of an electron inside the sample, provided the energy of the light photon and kinetic energy of the outgoing photoelectron are known. Momentum conservation makes it also possible to estimate k relating it to the momentum of the photoelectron by measuring the angle at which the photoelectron left the surface. The modern version of this technique is called Angle-Resolved Photoemission Spectroscopy (ARPES) and exploits both conservation laws in order to determine the electronic structure, i.e. energy and momentum of electrons inside the solid. In order to resolve the details crucial for understanding the topical problems of condensed matter physics, three quantities need to be minimized: uncertainty* in photon energy, uncertainty in kinetic energy of photoelectrons and temperature of the sample.
In our approach we combine three recent achievements in the field of synchrotron radiation, surface science and cryogenics. We use synchrotron radiation with tunable photon energy contributing an uncertainty of the order of 1 meV, an electron energy analyzer which detects the kinetic energies with a precision of the order of 1 meV and a He3 cryostat which allows us to keep the temperature of the sample below 1 K. We discuss the exemplary results obtained on single crystals of Sr2RuO4 and some other materials. The electronic structure of this material can be determined with an unprecedented clarity.

The overall goal of this method is to determine the low-energy electronic structure of solids at ultra-low temperatures using Angle-Resolved Photoemission Spectroscopy with synchrotron radiation.

超低温での角度分解光電子分光

The physical properties of a material are defined by its  electronic structure. Electrons in solids are characterized by energy (&omega;)  and momentum ...

Synthesis and Microdiffraction at Extreme Pressures and Temperatures

High pressure compounds and polymorphs are investigated for a broad range of purposes such as determine structures and processes of deep planetary interiors, design materials with novel properties, understand the mechanical behavior of materials exposed to very high stresses as in explosions or impacts. Synthesis and structural analysis of materials at extreme conditions of pressure and temperature entails remarkable technical challenges. In the laser heated diamond anvil cell (LH-DAC), very high pressure is generated between the tips of two opposing diamond anvils forced against each other; focused infrared laser beams, shined through the diamonds, allow to reach very high temperatures on samples absorbing the laser radiation. When the LH-DAC is installed in a synchrotron beamline that provides extremely brilliant x-ray radiation, the structure of materials under extreme conditions can be probed in situ. LH-DAC samples, although very small, can show highly variable grain size, phase and chemical composition. In order to obtain the high resolution structural analysis and the most comprehensive characterization of a sample, we collect diffraction data in 2D grids and combine powder, single crystal and multigrain diffraction techniques. Representative results obtained in the synthesis of a new iron oxide, Fe4O5 1 will be shown.

The laser heated diamond anvil cell combined with synchrotron micro-diffraction techniques allows researchers to explore the nature and properties of new phases of matter at extreme pressure and temperature (PT) conditions. Heterogeneous samples can be characterized in situ under high pressure by 2D mapping and combined powder, single-crystal and multigrain diffraction approaches.

エクストリーム圧力と温度での合成とMicrodiffraction

High pressure compounds and polymorphs are investigated for a broad range of purposes such as determine structures and processes of deep planetary ...

How to Ignite an Atmospheric Pressure Microwave Plasma Torch without Any Additional Igniters

This movie shows how an atmospheric pressure plasma torch can be ignited by microwave power with no additional igniters. After ignition of the plasma, a stable and continuous operation of the plasma is possible and the plasma torch can be used for many different applications. On one hand, the hot (3,600 K gas temperature) plasma can be used for chemical processes and on the other hand the cold afterglow (temperatures down to almost RT) can be applied for surface processes. For example chemical syntheses are interesting volume processes. Here the microwave plasma torch can be used for the decomposition of waste gases which are harmful and contribute to the global warming but are needed as etching gases in growing industry sectors like the semiconductor branch. Another application is the dissociation of CO2. Surplus electrical energy from renewable energy sources can be used to dissociate CO2 to CO and O2. The CO can be further processed to gaseous or liquid higher hydrocarbons thereby providing chemical storage of the energy, synthetic fuels or platform chemicals for the chemical industry. Applications of the afterglow of the plasma torch are the treatment of surfaces to increase the adhesion of lacquer, glue or paint, and the sterilization or decontamination of different kind of surfaces. The movie will explain how to ignite the plasma solely by microwave power without any additional igniters, e.g., electric sparks. The microwave plasma torch is based on a combination of two resonators &#8212; a coaxial one which provides the ignition of the plasma and a cylindrical one which guarantees a continuous and stable operation of the plasma after ignition. The plasma can be operated in a long microwave transparent tube for volume processes or shaped by orifices for surface treatment purposes.

This movie shows how an atmospheric plasma torch can be ignited by microwaves with no additional igniters and provides a stable and continuous plasma operation suitable for plenty of applications.

追加のイグナイタずに大気圧マイクロ波プラズマトーチに点火する方法

This movie shows how an atmospheric pressure plasma torch can be ignited by microwave power with no additional igniters. After ignition of the plasma, a ...

Emission Spectroscopic Boundary Layer Investigation during Ablative Material Testing in Plasmatron

Ablative Thermal Protection Systems (TPS) allowed the first humans to safely return to Earth from the moon and are still considered as the only solution for future high-speed reentry missions. But despite the advancements made since Apollo, heat flux prediction remains an imperfect science and engineers resort to safety factors to determine the TPS thickness. This goes at the expense of embarked payload, hampering, for example, sample return missions. 
Ground testing in plasma wind-tunnels is currently the only affordable possibility for both material qualification and validation of material response codes. The subsonic 1.2MW Inductively Coupled Plasmatron facility at the von Karman Institute for Fluid Dynamics is able to reproduce a wide range of reentry environments. This protocol describes a procedure for the study of the gas/surface interaction on ablative materials in high enthalpy flows and presents sample results of a non-pyrolyzing, ablating carbon fiber precursor. With this publication, the authors envisage the definition of a standard procedure, facilitating comparison with other laboratories and contributing to ongoing efforts to improve heat shield reliability and reduce design uncertainties.
The described core techniques are non-intrusive methods to track the material recession with a high-speed camera along with the chemistry in the reactive boundary layer, probed by emission spectroscopy. Although optical emission spectroscopy is limited to line-of-sight measurements and is further constrained to electronically excited atoms and molecules, its simplicity and broad applicability still make it the technique of choice for analysis of the reactive boundary layer. Recession of the ablating sample further requires that the distance of the measurement location with respect to the surface is known at all times during the experiment. Calibration of the optical system of the applied three spectrometers allowed quantitative comparison. At the fiber scale, results from a post-test microscopy analysis are presented.

Development of new ablative materials and their numerical modeling requires extensive experimental investigation. This protocol describes procedures for material response characterization in plasma flows with the core techniques being non-intrusive methods to track the material recession along with the chemistry in the reactive boundary layer by emission spectroscopy.

プラズマトロン内のアブレーション材料試験中の放射分光境界層調査

Ablative Thermal Protection Systems (TPS) allowed the first humans to safely return to Earth from the moon and are still considered as the only solution ...

High-resolution Thermal Micro-imaging Using Europium Chelate Luminescent Coatings

Micro-electronic devices often undergo significant self-heating when biased to their typical operating conditions. This paper describes a convenient optical micro-imaging technique which can be used to map and quantify such behavior. Europium thenoyltrifluoroacetonate (EuTFC) has a 612 nm luminescence line whose activation efficiency drops strongly with increasing temperature, due to T-dependent interactions between the Eu3+ ion and the organic chelating compound. This material may be readily coated on to a sample surface by thermal sublimation in vacuum. When the coating is excited with ultraviolet light (337 nm) an optical micro-image of the 612 nm luminescent response can be converted directly into a map of the sample surface temperature. This technique offers spatial resolution limited only by the microscope optics (about 1 micron) and time resolution limited by the speed of the camera employed. It offers the additional advantages of only requiring comparatively simple and non-specialized equipment, and giving a quantitative probe of sample temperature.

Europium thenoyltrifluoroacetonate (EuTFC) has an optical luminescence line at 612 nm, whose activation efficiency decreases strongly with temperature. If a sample coated with a thin film of this material is micro-imaged, the 612 nm luminescent response intensity may be converted into a direct map of sample surface temperature.

ユーロピウムキレート発光塗料を用いた高解像度サーマルマイクロイメージング

Micro-electronic devices often undergo significant self-heating when biased to their typical operating conditions. This paper describes a convenient ...

High Pressure Single Crystal Diffraction at PX^2

In this report we describe detailed procedures for carrying out single crystal X-ray diffraction experiments with a diamond anvil cell (DAC) at the GSECARS 13-BM-C beamline at the Advanced Photon Source. The DAC program at 13-BM-C is part of the Partnership for Extreme Xtallography (PX^2) project. BX-90 type DACs with conical-type diamond anvils and backing plates are recommended for these experiments. The sample chamber should be loaded with noble gas to maintain a hydrostatic pressure environment. The sample is aligned to the rotation center of the diffraction goniometer. The MARCCD area detector is calibrated with a powder diffraction pattern from LaB6. The sample diffraction peaks are analyzed with the ATREX software program, and are then indexed with the RSV software program. RSV is used to refine the UB matrix of the single crystal, and with this information and the peak prediction function, more diffraction peaks can be located. Representative single crystal diffraction data from an omphacite (Ca0.51Na0.48)(Mg0.44Al0.44Fe2+0.14Fe3+0.02)Si2O6 sample were collected. Analysis of the data gave a monoclinic lattice with P2/n space group at 0.35 GPa, and the lattice parameters were found to be: a = 9.496 &#177;0.006 &#197;, b = 8.761 &#177;0.004 &#197;, c = 5.248 &#177;0.001 &#197;, &#946; = 105.06 &#177;0.03&#186;, &#945; = &#947; = 90&#186;.

In this report, we describe detailed procedures for carrying out single crystal X-ray diffraction experiments with a diamond anvil cell at the GSECARS 13-BM-C beamline at the Advanced Photon Source. ATREX and RSV programs are used to analyze the data.

PX ^ 2の高圧単結晶回折

In this report we describe detailed procedures for carrying out single crystal X-ray diffraction experiments with a diamond anvil cell (DAC) at the ...

化学

Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry

A flowing microwave plasma based methodology for converting electric energy into internal and/or translational modes of stable molecules with the purpose of efficiently driving non-equilibrium chemistry is discussed. The advantage of a flowing plasma reactor is that continuous chemical processes can be driven with the flexibility of startup times in the seconds timescale. The plasma approach is generically suitable for conversion/activation of stable molecules such as CO2, N2 and CH4. Here the reduction of CO2 to CO is used as a model system: the complementary diagnostics illustrate how a baseline thermodynamic equilibrium conversion can be exceeded by the intrinsic non-equilibrium from high vibrational excitation. Laser (Rayleigh) scattering is used to measure the reactor temperature and Fourier Transform Infrared Spectroscopy (FTIR) to characterize in situ internal (vibrational) excitation as well as the effluent composition to monitor conversion and selectivity.

This article describes a flowing microwave reactor that is used to drive efficient non-equilibrium chemistry for the application of conversion/activation of stable molecules such as CO2, N2 and CH4. The goal of the procedure described here is to measure the in situ gas temperature and gas conversion.

効率的な高温化学反応のための非平衡マイクロ波プラズマ

A flowing microwave plasma based methodology for converting electric energy into internal and/or translational modes of stable molecules with the purpose ...

An Atmospheric Pressure Plasma Setup to Investigate the Reactive Species Formation

Non-thermal atmospheric pressure (&#39;cold&#39;) plasmas have received increased attention in recent years due to their significant biomedical potential. The reactions of cold plasma with the surrounding atmosphere yield a variety of reactive species, which can define its effectiveness. While efficient development of cold plasma therapy requires kinetic models, model benchmarking needs empirical data. Experimental studies of the source of reactive species detected in aqueous solutions exposed to plasma are still scarce. Biomedical plasma is often operated with He or Ar feed gas, and a specific interest lies in investigation of the reactive species generated by plasma with various gas admixtures (O2, N2, air, H2O vapor, etc.) Such investigations are very complex due to difficulties in controlling the ambient atmosphere in contact with the plasma effluent. In this work, we addressed common issues of &#39;high&#39; voltage kHz frequency driven plasma jet experimental studies. A reactor was developed allowing the exclusion of ambient atmosphere from the plasma-liquid system. The system thus comprised the feed gas with admixtures and the components of the liquid sample. This controlled atmosphere allowed the investigation of the source of the reactive oxygen species induced in aqueous solutions by He-water vapor plasma. The use of isotopically labelled water allowed distinguishing between the species originating in the gas phase and those formed in the liquid. The plasma equipment was contained inside a Faraday cage to eliminate possible influence of any external field. The setup is versatile and can aid in further understanding the cold plasma-liquid interactions chemistry.

An experimental setup was created for the helium-operated kHz frequency plasma jet. The setup includes a cage for the plasma power supply and jet and an in-house built reactor to monitor plasma-induced reactive species without the interference of the ambient atmosphere.

反応種の形成を調査するための大気圧プラズマのセットアップ

Non-thermal atmospheric pressure (&#39;cold&#39;) plasmas have received increased attention in recent years due to their significant biomedical potential. ...

Spark Plasma Sintering Apparatus Used for the Formation of Strontium Titanate Bicrystals

A spark plasma sintering apparatus was used as a novel method for diffusion bonding of two single crystals of strontium titanate to form bicrystals with one twist grain boundary. This apparatus utilizes high uniaxial pressure and a pulsed direct current for rapid consolidation of material. Diffusion bonding of strontium titanate bicrystals without fracture, in a spark plasma sintering apparatus, is possible at high pressures due to the unusual temperature dependent plasticity behavior of strontium titanate. We demonstrate a method for the successful formation of bicrystals at accelerated time scales and lower temperatures in a spark plasma sintering apparatus compared to bicrystals formed by conventional diffusion bonding parameters. Bond quality was verified by scanning electron microscopy. A clean and atomically abrupt interface containing no secondary phases was observed using transmission electron microscopy techniques. Local changes in bonding across the boundary was characterized by simultaneous scanning transmission electron microscopy and spatially resolved electron energy-loss spectroscopy.

A viable technique for the formation of strontium titanate bicrystals at high pressure and fast heating rate via the spark plasma sintering apparatus is developed.

チタン酸ストロンチウム双結晶の形成に用いられるプラズマ焼結装置をスパーク

A spark plasma sintering apparatus was used as a novel method for diffusion bonding of two single crystals of strontium titanate to form bicrystals with ...