DOCSLIB.ORG

Developments of Various Low Energy RF Linear Accelerators at KAERI &

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Developments of Various Low Energy RF Linear Accelerators at KAERI & November 16th, 2017, Gyeongju, Korea Developments of Various Low Energy RF Linear Accelerators at KAERI & RTX Pikad Buaphad, Yujong Kim, Kibaek Song, Hyungdal Park, Sungsu Cha, Youngwoo Joo, Byeongchul Lee, and Siyoung Ryu Radiation Technology eXcellence, Daejeon, Korea Future Accelerator R&D Team, Nucleat Data Center, KAERI, Daejeo, Korea University of Science and Technology, Daejeon, Korea [email protected] Outline Introduction to Low Energy Electron Linac Developments of Industrial Electron Linac at KAERI & RTX 9/6 MeV Multi-Energy American S-band (=2856 MHz) Linac 9/6 MeV Dual Energy European S-band (=2998 MHz) Linac 6 MeV High Gradient European S-band (=2998 MHz) Linac Photocathode RF Gun Developments at KAERI Medical Electron Linac Developments at KAERI & RTX 6 MeV X-band (=9300 MHz) Linac 6 MeV Higher Gradient X-band (=9300 MHz) Linac Summary 2 Application of Low Energy Electron Accelerator Different mechanisms of radiation interaction with matter are used for different applications. Some applications use electron beam but most of the applications uses the bremsstrahlung (X-ray) radiations. X-rays penetrate deeper in matter than electron beam. 3 Low Energy RF Electron Linac System RF Accelerating Structure X-ray Target E-GUN Ion E-GUN Reflected Pump PS RF Circulator Forward RF Modulator (H.V. Pulse PS) Magnetron L-band: f ~ 1.5 GHz (l ~ 10 cm) Ion S-band: f ~ 3 GHz (l ~ 5 cm) Pump C-band: f ~ 5 GHz (l ~ 3 cm) X-band: f ~ 9-12 GHz (l ~ 1.5 cm) 4 What’s Important for Developing a Linac ? Reliability and Stability Performance to meet the Requirements Dose Rate Keeping an Energy with a Small Energy Spread High Capture of Injected Electron from Gun Low and High Current Capability The simpler is better Easy for Operating and Maintenance Low Radiation Loss 5 9/6 MeV American S-band RF Electron Linac RF Frequency = 2856 MHz 6 9/6 MeV American S-band RF Electron Linac E-beam energy : 9/6 MeV Penetration Depth (steel 380 mm @ 9 MeV, 30 Gy/min @ 1 m ) Spot size : < 2 mm Resolution Average power: > 1 kW Scan Speed (0.3 m/s, < 1-2 min @ 1 kW) Energy Switch mode None Destructive Testing RF Frequency = 2856 MHz Structure length ~ 0.57 m 7 9/6 MeV European S-band RF Electron Linac Structure length ~ 0.64 m European S-band to use a cheaper and low power (3.1 MW) magnetron8 6 MeV European S-band RF Electron Linac Beam Motion along 6 MeV Linac Structure - CST Particle Studio, PIC 9 6 MeV European S-band RF Electron Linac Structure length ~ 0.3 m 10 American S-band Photocathode RF Gun ● 1.6 RF-gun with Operation Frequency 2856 MHz, π-mode ● Mode Separation of 15.5 MHz For Ultrafast Applications (UED, UEM) 11 6 MeV X-band Linac for Medical Applications For the medical applications (CyberKnife & dual head gantry), we promised following parameters: RF Frequency ~ 9.3 GHz beam energy ≥ 6 MeV dose rate ≥ 500 cGy/min target spotsize ≤ 2 mm (FW) To supply those parameters, we are developing new X-band electron linacs. gun gap voltage ~ 20 kV peak current at gun exit ~ 100 - 200 mA peak energy at linac exit ~ 6 MeV beam capturing coefficient ~ 50% average beam power ~ 167 W for 500 cGy/min peak / average current at linac exit ≥ 50 - 100 mA / 28 µA for 500 cGy/min with a duty factor 0.0009 duty factor of L3 magnetron: ~ 0.0002 (2 MW) - 0.0008 (1.7 MW). duty factor of CPI magnetron: ~ 0.0018 (1.5 MW) 12 6 MeV X-band Linac We assume that energy gain at a half cell is 125 keV and energy gain at a full cell is 245 keV. The π-mode has been chosen as the operating mode since it provides the highest shunt impedance and it also gives the highest energy gain for a given power. With every acceleration, the electron bunch travels a greater distance in the same amount of time. Thus, the length of the cavities must also increase as the bunch velocity increases. õ ⁄̋ õ Â ƔÌ ̘̌ Ɣ ì ̘̌ ̶̴̡̣̩̹ ¹ ̋ 13 6 MeV X-band Linac KAERI & RTX teams designed an X-band linac structure with 24.5 cells. Bunching cells: 10.5 cells with energy gains of 125 - 245 keV Accelerating cells: 14 cells with 16 MV/m (coupler @ 14th cell) central frequency ~ 9.302 GHz length ~ 0.4 m unloaded Q0 ~ 11319 external Qext ~ 10197 coupling beta ~ 1.11 shunt impedance ~ 80 MΩ/m RF power for 6 MeV ~ 1.5 MW 14 6 MeV X-band Linac Beam Motion along 6 MeV X-band Linac Structure - CST Particle Studio, PIC Without considering the space charge effect, the phase motion of the electron with different initial phases and energy gain were calculated by solving the equation of motion. About 49% of the electrons can reach to the end of Linac structure, but only electrons with initial phase between 150º and 317º have the final energy to reach to 6 MeV. The capture efficiency of Linac structure is about 46% with energy spread of 9%. 15 X-band Linac ASTRA Simulation Optimization Results with 1,000,000 particles for 3 RF periods (108 ps × 3 = 324 ps) peak current ~ 3.6 pC/30 ps > 120 mA energy spread ~ 15% Transverse beam properties of first single head bunch 16 X-band Linac 3D Drawing 24.5 cells with 10 bunching cells central frequency ~ 9.302 GHz length ~ 0.4 m unloaded Q ~ 11319 coupling beta ~ 1.11 Rsh ~ 80 M Ω/m Power for 6 MeV ~ 1.5 MW Cell length ~ 16.1 mm Radius ~ 14.2 mm Gradient ~ 17 MV/m Weight ~ 8 kg 17 X-band Linac Fabrication - Cells Cells for X-band linac 18 X-band Linac Fabrication Brazed coupler cell for X-band linac Tuners for X-band linac 19 X-band Linac - Fabricated Linac SSS111111 Right After Fabrication KAERI did Great Design & Fabrication! π mode ~ 9.302 GHz with -5.0 dB 20 X-band Linac - Fabricated Linac SSS111111 After Final Tuning @ Tempearture = 30 degree KAERI did Great Tuning! π mode ~ 9312.31 MHz with -27 dB (0.2% reflection) 21 X-band Linac – Bead-pull Measurement 7 6 5 4 E (A.U) E 3 2 1 0 0 500 1000 1500 2000 2500 3000 position number 22 Photo of Assembled X-band Linac 23 RF Condition with 2.1 MW We could finish RF condition only with one day! 2.1 MW full power, 4 µs, 2 Hz, Vacuum ~ 1.0E-8 Torr This is a good indication of our great jobs! quiet vacuum << 1.0E-6 Torr green: forward yellow: reflected blue: modulator HV Beam On: -1 kV + Drive (50 V) Beam Off: -1 kV -50 V Faraday Cup Trigger 24 1st Beam from X-band Linac - Nov. 14th, 2014 We could get the first beam from the 6 MeV X-band linac on November 14th, 2014! 2.1 MW full power, 4 µs, 2 Hz, Vacuum ~ 1.0E-8 Torr Our X-band design worked! 25 Higher Gradient X-band Linac - RTX & KAERI An X-band linac with a higher gradient (~ 30 MV/m) is needed for the Dual-Head Gantry project (30% reduction of therapy time). KAERI & RTX have been developing the higher gradient X-band linac. 26 Higher Gradient X-band Linac - RTX & KAERI KAERI and RTX have been developing an higher gradient X-band linac! We assume that energy gain at a half cell is 240 keV and energy gain at a full cell is 500 keV. Bunching cells: 4.5 cells with energy gains of 240 - 500 keV Accelerating cells: 8 cells with 16 MV/m (coupler @ last cell) The length of beam pipe at half cell is 8 mm with a radius of 2.5 mm. However the beam pipe length at the last cell is 16.5 with a radius of 5 mm. 27 Higher Gradient X-band Linac - RTX & KAERI 28 Summary There are various growing user applications with MeV-range RF electron linacs. KAERI has successfully developed a 9/6 MeV multi-energy American S-band (=2856 MHz) electron linac for NDT applications. To reduce magnetron cost, KAERI also has successfully developed a 9/6 MeV dual energy and a 6 MeV European S-band (=2998 MHz) electron linacs for CIS and NDT applications. RTX already commercialized these accelerators for CIS and NDT applications. KAERI and RTX have successfully developed a 6 MeV X-band (=9300 MHz) electron linac for medical applications. KAERI and RTX finished design of a new 6 MeV X-band linac with a higher gradient of about 30 MV/m. Moreover KAERI and RTX finished design of a photocathode RF gun for ultrafast electron beam sciences (UED and UEM) with our collaborators (KRISS and GIST) 29.
Load more

Recommended publications
  • Spectrum and the Technological Transformation of the Satellite Industry Prepared by Strand Consulting on Behalf of the Satellite Industry Association1
    Spectrum & the Technological Transformation of the Satellite Industry Spectrum and the Technological Transformation of the Satellite Industry Prepared by Strand Consulting on behalf of the Satellite Industry Association1 1 AT&T, a member of SIA, does not necessarily endorse all conclusions of this study. Page 1 of 75 Spectrum & the Technological Transformation of the Satellite Industry 1. Table of Contents 1. Table of Contents ................................................................................................ 1 2. Executive Summary ............................................................................................. 4 2.1. What the satellite industry does for the U.S. today ............................................... 4 2.2. What the satellite industry offers going forward ................................................... 4 2.3. Innovation in the satellite industry ........................................................................ 5 3. Introduction ......................................................................................................... 7 3.1. Overview .................................................................................................................. 7 3.2. Spectrum Basics ...................................................................................................... 8 3.3. Satellite Industry Segments .................................................................................... 9 3.3.1. Satellite Communications ..............................................................................
    [Show full text]
  • A Layman's Interpretation Guide L-Band and C-Band Synthetic
    A Layman’s Interpretation Guide to L-band and C-band Synthetic Aperture Radar data Version 2.0 15 November, 2018 Table of Contents 1 About this guide .................................................................................................................................... 2 2 Briefly about Synthetic Aperture Radar ......................................................................................... 2 2.1 The radar wavelength .................................................................................................................... 2 2.2 Polarisation ....................................................................................................................................... 3 2.3 Radar backscatter ........................................................................................................................... 3 2.3.1 Sigma-nought .................................................................................................................................................. 3 2.3.2 Gamma-nought ............................................................................................................................................... 3 2.4 Backscatter mechanisms .............................................................................................................. 4 2.4.1 Direct backscatter ......................................................................................................................................... 4 2.4.2 Forward scattering ......................................................................................................................................
    [Show full text]
  • Wide-Band, Low-Frequency Pulse Profiles of 100 Radio Pulsars With
    A&A 586, A92 (2016) Astronomy DOI: 10.1051/0004-6361/201425196 & c ESO 2016 Astrophysics Wide-band, low-frequency pulse profiles of 100 radio pulsars with LOFAR M. Pilia1,2, J. W. T. Hessels1,3,B.W.Stappers4, V. I. Kondratiev1,5,M.Kramer6,4, J. van Leeuwen1,3, P. Weltevrede4, A. G. Lyne4,K.Zagkouris7, T. E. Hassall8,A.V.Bilous9,R.P.Breton8,H.Falcke9,1, J.-M. Grießmeier10,11, E. Keane12,13, A. Karastergiou7 , M. Kuniyoshi14, A. Noutsos6, S. Osłowski15,6, M. Serylak16, C. Sobey1, S. ter Veen9, A. Alexov17, J. Anderson18, A. Asgekar1,19,I.M.Avruch20,21,M.E.Bell22,M.J.Bentum1,23,G.Bernardi24, L. Bîrzan25, A. Bonafede26, F. Breitling27,J.W.Broderick7,8, M. Brüggen26,B.Ciardi28,S.Corbel29,11,E.deGeus1,30, A. de Jong1,A.Deller1,S.Duscha1,J.Eislöffel31,R.A.Fallows1, R. Fender7, C. Ferrari32, W. Frieswijk1, M. A. Garrett1,25,A.W.Gunst1, J. P. Hamaker1, G. Heald1, A. Horneffer6, P. Jonker20, E. Juette33, G. Kuper1, P. Maat1, G. Mann27,S.Markoff3, R. McFadden1, D. McKay-Bukowski34,35, J. C. A. Miller-Jones36, A. Nelles9, H. Paas37, M. Pandey-Pommier38, M. Pietka7,R.Pizzo1,A.G.Polatidis1,W.Reich6, H. Röttgering25, A. Rowlinson22, D. Schwarz15,O.Smirnov39,40, M. Steinmetz27,A.Stewart7, J. D. Swinbank41,M.Tagger10,Y.Tang1, C. Tasse42, S. Thoudam9,M.C.Toribio1,A.J.vanderHorst3,R.Vermeulen1,C.Vocks27, R. J. van Weeren24, R. A. M. J. Wijers3, R. Wijnands3, S. J. Wijnholds1,O.Wucknitz6,andP.Zarka42 (Affiliations can be found after the references) Received 20 October 2014 / Accepted 18 September 2015 ABSTRACT Context.
    [Show full text]
  • Potential of Different Optical and SAR Data in Forest and Land Cover Classification to Support REDD+ MRV
    remote sensing Article Potential of Different Optical and SAR Data in Forest and Land Cover Classification to Support REDD+ MRV Laura Sirro 1,*, Tuomas Häme 1, Yrjö Rauste 1, Jorma Kilpi 1 ID , Jarno Hämäläinen 2, Katja Gunia 2, Bernardus de Jong 3 and Fernando Paz Pellat 4 1 VTT Technical Research Centre of Finland Ltd., P.O. Box 1000, VTT FI-02044, Finland; tuomas.hame@vtt.fi (T.H.); yrjo.rauste@vtt.fi (Y.R.); jorma.kilpi@vtt.fi (J.K.) 2 Arbonaut Ltd., Kaislakatu 2, Joensuu FI-80130, Finland; [email protected] (J.H.); [email protected] (K.G.) 3 El Colegio de la Frontera Sur, Av. Rancho Polígono 2-A, Parque Industrial Lerma, Campeche, Campeche CP 24500, Mexico; [email protected] 4 Colegio de Postgraduados, Km 36.5 Carretera México-Texcoco, Texcoco 56230, Mexico; [email protected] * Correspondence: laura.sirro@vtt.fi; Tel.: +358-40-538-7769 Received: 9 May 2018; Accepted: 11 June 2018; Published: 14 June 2018 Abstract: The applicability of optical and synthetic aperture radar (SAR) data for land cover classification to support REDD+ (Reducing Emissions from Deforestation and Forest Degradation) MRV (measuring, reporting and verification) services was tested on a tropical to sub-tropical test site. The 100 km by 100 km test site was situated in the State of Chiapas in Mexico. Land cover classifications were computed using RapidEye and Landsat TM optical satellite images and ALOS PALSAR L-band and Envisat ASAR C-band images. Identical sample plot data from Kompsat-2 imagery of one-metre spatial resolution were used for the accuracy assessment.
    [Show full text]
  • VHF and L-Band Scintillation Characteristics Over an Indian Low Latitude Station, Waltair (17.7◦ N, 83.3◦ E)
    Annales Geophysicae, 23, 2457–2464, 2005 SRef-ID: 1432-0576/ag/2005-23-2457 Annales © European Geosciences Union 2005 Geophysicae VHF and L-band scintillation characteristics over an Indian low latitude station, Waltair (17.7◦ N, 83.3◦ E) P. V. S. Rama Rao, S. Tulasi Ram, K. Niranjan, D. S. V. V. D. Prasad, S. Gopi Krishna, and N. K. M. Lakshmi Space Physics Laboratories, Department of Physics, Andhra University, Visakhapatnam 530 003, India Received: 30 April 2005 – Revised: 6 August 2005 – Accepted: 10 August 2005 – Published: 14 October 2005 Abstract. Characteristics of simultaneous VHF (244 MHz) tures in the Range-Time-Intensity (RTI) images of HF radars, and L-band (1.5 GHz) scintillations recorded at a low- intensity bite-outs in airglow intensity measurements and latitude station, Waltair (17.7◦ N, 83.3◦ E), during the low scintillations on amplitude, as well as the phase of VHF and sunspot activity year of March 2004 to March 2005, sug- UHF signals from satellites, and are commonly referred to as gest that the occurrence of scintillations is mainly due to two Equatorial Spread-F irregularities (ESF). The ESF is mostly types, namely the Plasma Bubble Induced (PBI), which max- confined to the equatorial belt of ±20◦ magnetic latitudes, imizes during the post sunset hours of winter and equinoctial encompassing the Equatorial Ionization Anomaly (EIA) re- months, and the Bottom Side Sinusoidal (BSS) type, which gion. maximizes during the post-midnight hours of the summer Woodman and Lahoz (1976) classified the irregularities solstice
    [Show full text]
  • L- and X-Band Like- and Cross-Polarized Synthetic Aperture Radar for Investigating ! Urban Environments
    BARRYN. HMCK* Regional Remote Sensing Facility Nairobi, Kenya L- and X-Band Like- and Cross-Polarized Synthetic Aperture Radar for Investigating ! Urban Environments The X-band like-polarized data were the most useful, the L-band cross- polarized data were the least useful, and the texture calculations used in this study did not contribute toward urban cover type delineations. 1982) and texture analysis (Fasler, 1980); and for different environments, i.e., geology (Ford, 1980), HE EXAMINATION of radar data for the mapping agriculture (Ulaby and Bare, 1980), land use (Hen- T and analysis of Earth surface features has con- derson, 1979), and urban (Bryan, 1979). The pur- siderably increased in the last few years. Much of pose of this study was to examine two synthetic ap- this increase is a function of the recent availability erture radar (SAR)bands, L-band and X-band, at both of these data. The increase is also due to the aware- like- and cross-polarizations in order to assess their ness that radar has unique attributes, such as its all- usefulness for urban land-cover delineations. Rather weather and night and day capabilities, which may than a visual analysis of images as has been done make it a very useful tool for resource inventory and previously with similar data, this study examined ABSTRACT:Four synthetic aperture airborne radar data sets, L- and x-band like- and cross-polarizations, were spatially registered to a common map base for a portion of the Los Angeles basin. Texture calculations for the four SAR data sets were also obtained.
    [Show full text]
  • Soil Dielectric Characterization at L-Band Microwave Frequencies
    https://doi.org/10.5194/hess-2020-291 Preprint. Discussion started: 10 July 2020 c Author(s) 2020. CC BY 4.0 License. Soil dielectric characterization at L-band microwave frequencies during freeze-thaw transitions Alex Mavrovic1-2, Renato Pardo Lara3, Aaron Berg3, François Demontoux4, Alain Royer5- 2, Alexandre Roy1-2 5 1 Université du Québec à Trois-Rivières, Trois-Rivières, Québec, G9A 5H7, Canada 2 Centre d’Études Nordiques, Université Laval, Québec, Québec, G1V 0A6, Canada 3 University of Guelph, Guelph, Ontario, N1G 2W1, Canada 4 Laboratoire de l'Intégration du Matériau au Système, Bordeaux, 33400 Talence, France 5 Centre d’Applications et de Recherches en Télédétection, Université de Sherbrooke, Sherbrooke, Québec, 10 J1K 2R1, Canada Correspondence to: Alex Mavrovic ([email protected]) Abstract. Soil microwave permittivity is a crucial parameter in passive microwave retrieval algorithms but remains a challenging variable to measure. To validate and improve satellite microwave data products, 15 precise and reliable estimations of the relative permittivity (ɛr = ɛ/ɛ0 = ɛ’-jɛ’’; unitless) of soils are required, particularly for frozen soils. In this study, permittivity measurements were acquired using two different instruments: the newly designed open-ended coaxial probe (OECP) and the conventional Stevens HydraProbe. Both instruments were used to characterize the permittivity of soil samples undergoing several freeze/thaw cycles in a laboratory environment. The measurements were compared to soil permittivity 20 models. We show that the OECP is a suitable device for measuring frozen (ɛ’frozen = [3.5;6.0], ɛ’’frozen = [0.4;1.2]) and thawed (ɛ’thawed = [6.5;22.8], ɛ’’thawed = [1.4;5.7]) soil microwave permittivity.
    [Show full text]
  • Spectrum-Secure Communications for Autonomous Uas/Uav Platforms
    SPECTRUM‐SECURE COMMUNICATIONS FOR AUTONOMOUS UAS/UAV PLATFORMS Andrew L. Drozd ANDRO Computational Solutions, LLC Advanced Applied Technology Division Rome, NY 26 October 2015 Secure UAS Communications Panel 1 Unclassified // Distribution A: Unlimited Distribution Topics • ANDRO Technology Summary • Background of key technical issues related to UAS/UAV spectrum, safety, security and airspace integration . Potential spectrum contention and management issues Frequencies Used for Remote Control A Typical UAV Link UAS Integration to NAS . Spectrum, Security and RTCA‐228 Relevant Issues • Conclusion 2 ANDRO Technology / Application Spaces C2 (Cross‐layer RF Cyber‐Spectrum RF Resource Exploitation Management & Communications / Cyber Security) (Wireless Anti‐ EMI Avoidance Dynamic Spectrum Hacking) (Coexistence) Access/Sharing Spectrum Pre‐test M&S Detect & Avoid (Spectral Contention) Cyber‐Spectrum Exploitation / Secure Wireless Comms / Cognitive Radio Networking / 3 Trusted Routing Technologies for Autonomous Systems (RF sensor‐edge processing) BACKGROUND • ANDRO has access to AFRL’s Stockbridge Controllable Contested Environment Facility and Griffiss FAA UAS Test Site Rome, NY for communications up/down‐link experiments with large or small UAS/UAV platforms. • Member of Northeast UAS Airspace Integration Research Alliance (NUAIR). • Our overall focus is on assessing, pre‐certifying or assuring the following for C2/CDL, payload data link (VDL) and other future RF comms technologies: – RF spectrum collision/contention – Coexistence – Cyber
    [Show full text]
  • Ultra-Wideband WDM Optical Network Optimization
    hv photonics Article Ultra-Wideband WDM Optical Network Optimization Stanisław Kozdrowski 1,* , Mateusz Zotkiewicz˙ 1 and Sławomir Sujecki 2,3 1 Department of Computer Science, Faculty of Electronics, Warsaw University of Technology, Nowowiejska 15/19, 00-665 Warsaw, Poland; [email protected] 2 George Green Institute, the University of Nottingham, Nottingham NG7 2RD, UK; [email protected] 3 Telecommunications and Teleinformatics Department, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland * Correspondence: [email protected] Received: 6 December 2019; Accepted: 13 January 2020; Published: 21 January 2020 Abstract: Ultra-wideband wavelength division multiplexed networks enable operators to use more effectively the bandwidth offered by a single fiber pair and thus make significant savings, both in operational and capital expenditures. The main objective of this study is to minimize optical node resources, such as transponders, multiplexers and wavelength selective switches, needed to provide and maintain high quality of network services, in ultra-wideband wavelength division multiplexed networks, at low cost. A model based on integer programming is proposed, which includes a detailed description of optical network nodal resources. The developed optimization tools are used to study the ultra-wideband wavelength division multiplexed network performance when compared with the traditional C-band wavelength division multiplexed networks. The analysis is carried out for realistic networks of different dimensions and traffic demand sets. Keywords: ultra-Wideband WDM system design; optical network optimization; CDC-F technology; optical node model; network congestion; Linear Programming (LP); Integer Programming (IP) 1. Introduction Optical networks based on Wavelength Division Multiplexing (WDM) technology that operate within the C-band are near the limit of their capacity.
    [Show full text]
  • Complementarity of X-, C-, and L-Band SAR Backscatter Observations to Retrieve Forest Stem Volume in Boreal Forest
    remote sensing Article Complementarity of X-, C-, and L-band SAR Backscatter Observations to Retrieve Forest Stem Volume in Boreal Forest Maurizio Santoro 1,* , Oliver Cartus 1, Johan E. S. Fransson 2 and Urs Wegmüller 1 1 Gamma Remote Sensing, Worbstrasse 225, 3073 Gümligen, Switzerland 2 Department of Forest Resource Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden * Correspondence: [email protected]; Tel.: +41-31-9517005 Received: 28 May 2019; Accepted: 28 June 2019; Published: 2 July 2019 Abstract: The simultaneous availability of observations from space by remote sensing platforms operating at multiple frequencies in the microwave domain suggests investigating their complementarity in thematic mapping and retrieval of biophysical parameters. In particular, there is an interest to understand whether the wealth of short wavelength Synthetic Aperture Radar (SAR) backscatter observations at X-, C-, and L-band from currently operating spaceborne missions can improve the retrieval of forest stem volume, i.e., above-ground biomass, in the boreal zone with respect to a single frequency band. To this scope, repeated observations from TerraSAR-X, Sentinel-1 and ALOS-2 PALSAR-2 from the test sites of Remningstorp and Krycklan, Sweden, have been analyzed and used to estimate stem volume with a retrieval framework based on the Water Cloud Model. Individual estimates of stem volume were then combined linearly to form single-frequency and multi-frequency estimates. The retrieval was assessed at large 0.5 ha forest inventory plots (Remningstorp) and small 0.03 ha forest inventory plots (Krycklan). The relationship between SAR backscatter and stem volume differed depending on forest structure and environmental conditions, in particular at X- and C-band.
    [Show full text]
  • Vialitehd ® – L-Band HTS RF Over Fiber Link
    www.vialite.com +44 (0)1793 784389 [email protected] +1 (855) 4-VIALITE [email protected] ® ViaLiteHD – L-Band HTS RF over Fiber Link 75 Ohm L-Band HTS Standard 0-10 km link 65 dB dynamic range for 500 MHz traffic L-Band HTS (700-2450 MHz) 13/18 V and 22 KHz tone LNB option Blind mate option Standard 5-year warranty ViaLiteHD L-Band HTS fiber optic links have been designed for the broadcast satellite industry to transport RF signals between antennas and control rooms. Due to the very wide dynamic range, the same link can be used in both the transmit and receive paths. This dynamic range allows High Throughput Satellite (HTS) transponder bandwidths of 500, 800 or even 1500 MHz to be transported, as well as multiple standard 36 MHz transponders. The chassis cards are available with the blind mate option, which allows all cables to be connected at the rear of the chassis when installed. It also allows configuration changes to be completed without disturbing the connections and very fast changeover of cards; enabling five 9s reliability. Options include: • 75 Ω electrical connectors: BNC, F-Type and MCX • Optical connectors: SC/APC, LC/APC, FC/APC and E2000/APC • Test ports on Tx and Rx modules • Built-in BiasT for LNB powering through RF connection • LNB control circuit with 13/18 VDC and 22 kHz tone • Blind mate connectivity (SC/APC and BNC) • Serial digital channel to 20 kb/s on same optical path Applications Formats Broadcast facilities 3U Chassis Mobile SNG, military and flyaways 1U Chassis Television Receive-Only (TVRO) Blue OEM and Blue2 Link Fixed satcom earth stations and Teleports Yellow OEM VSAT hubs (IP gateways) Outdoor enclosures Marine antennas Telemetry, Tracking and Command (TT&C) Related Products 50 km 1550 nm L-Band HTS Oil and gas platforms 50 Ohm L-Band HTS HTS 100 km+ systems DWDM links ViaLiteHD_L_Band_75_Ohm_Datasheet_HRx-L1_DS_5.docx CR4505 20/07/2020 Due to our policy of continuing product development, these specifications are subject to change and improvement without notice.
    [Show full text]
  • SPEAR Far UV Spectral Imaging of Highly Ionized Emission from the North Galactic Pole Region
    A&A 472, 509–517 (2007) Astronomy DOI: 10.1051/0004-6361:20077685 & c ESO 2007 Astrophysics SPEAR far UV spectral imaging of highly ionized emission from the North Galactic Pole region B. Y. Welsh1, J. Edelstein1,E.J.Korpela1, J. Kregenow1, M. Sirk1,K.-W.Min2,J.W.Park2, K. Ryu2,H.Jin3,I.-S.Yuk3, and J.-H. Park3 1 Space Sciences Laboratory, University of California, 7 Gauss Way, Berkeley, CA 94720, USA e-mail: [email protected] 2 Korea Advanced Institute of Science & Technology, 305-70 Daejeon, Korea 3 Korea Astronomy & Space Science Institute, 305-348 Daejeon, Korea Received 20 April 2007 / Accepted 25 May 2007 ABSTRACT Aims. We present far ultraviolet (FUV: 912–1750 Å) spectral imaging observations recorded with the SPEAR satellite of the interstellar OVI (1032 Å), CIV (1550 Å), SiIV (1394 Å), SiII* (1533 Å) and AlII (1671 Å) emission lines originating in a 60◦ × 30◦ rectangular region lying close to the North Galactic Pole. These data represent the first large area, moderate spatial resolution maps of the distribution of UV spectral-line emission originating the both the highly ionized medium (HIM) and the warm ionized medium (WIM) recorded at high galactic latitudes. Methods. By assessing and removing a local continuum level that underlies these emission line spectra, we have obtained interstellar emission intensity maps for the aforementioned lines constructed in 8◦ × 8◦ spatial bins on the sky. Results. Our maps of OVI, CIV, SiIV and SiII* line emission show the highest intensity levels being spatially coincident with similarly high levels of soft X-ray emission originating in the edge of the Northern Polar Spur feature.
    [Show full text]