Linac design for the European spallation source

Energy Technology Data Exchange (ETDEWEB)

Klein, H. [Universitaet Postfach, Frankfurt am Main (Germany)

1995-10-01

A study group has started to develop a conceptual design for a European Spallation Source (ESS). This pulsed 5 MW source presently consists of a 1.334 GeV linac and two compressor rings. In the following mainly the high intensity linac part will be discussed, which has some features of interest for accelerators for transmutation of radioactive waste too.

S-band linac-based X-ray source with {pi}/2-mode electron linac

Energy Technology Data Exchange (ETDEWEB)

Deshpande, Abhay, E-mail: abhay@post.kek.jp [Department of Accelerator Science, School of High Energy Accelerator Science, Graduate University for Advanced Studies, Shonan International Village, Hayama, Miura, Kanagawa 240-0193 (Japan); Society for Applied Microwave Electronic Engineering and Research (SAMEER), R and D Laboratory of the Government of India, IIT Campus, Powai, Mumbai 400 076 (India); Araki, Sakae [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Dixit, Tanuja [Society for Applied Microwave Electronic Engineering and Research (SAMEER), R and D Laboratory of the Government of India, IIT Campus, Powai, Mumbai 400 076 (India); Fukuda, Masafumi [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Krishnan, R; Pethe, Sanjay [Society for Applied Microwave Electronic Engineering and Research (SAMEER), R and D Laboratory of the Government of India, IIT Campus, Powai, Mumbai 400 076 (India); Sakaue, Kazuyuki [Waseda University, Shinjuku-ku, Tokyo 169-8555 (Japan); Terunuma, Nobuhiro; Urakawa, Junji [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Washio, Masakazu [Waseda University, Shinjuku-ku, Tokyo 169-8555 (Japan)

2011-05-01

The activities with the compact X-ray source are attracting more attention, particularly for the applications of the source in medical fields. We propose the fabrication of a compact X-ray source using the SAMEER electron linear accelerator and the KEK laser undulator X-ray source (LUCX) technologies. The linac developed at SAMEER is a standing wave side-coupled S-band linac operating in the {pi}/2 mode. In the proposed system, a photocathode RF gun will inject bunches of electrons in the linac to accelerate and achieve a high-energy, low-emittance beam. This beam will then interact with the laser in the laser cavity to produce X-rays of a type well suited for various applications. The side-coupled structure will make the system more compact, and the {pi}/2 mode of operation will enable a high repetition rate operation, which will help to increase the X-ray yield.

X-band RF gun and linac for medical Compton scattering X-ray source

International Nuclear Information System (INIS)

Dobashi, Katsuhito; Uesaka, Mitsuru; Fukasawa, Atsushi; Sakamoto, Fumito; Ebina, Futaro; Ogino, Haruyuki; Urakawa, Junji; Higo, Toshiyasu; Akemoto, Mitsuo; Hayano, Hitoshi; Nakagawa, Keiichi

2004-01-01

Compton scattering hard X-ray source for 10-80 keV are under construction using the X-band (11.424 GHz) electron linear accelerator and YAG laser at Nuclear Engineering Research laboratory, University of Tokyo. This work is a part of the national project on the development of advanced compact medical accelerators in Japan. National Institute for Radiological Science is the host institute and U.Tokyo and KEK are working for the X-ray source. Main advantage is to produce tunable monochromatic hard (10-80 keV) X-rays with the intensities of 108-1010 photons/s (at several stages) and the table-top size. Second important aspect is to reduce noise radiation at a beam dump by adopting the deceleration of electrons after the Compton scattering. This realizes one beamline of a 3rd generation SR source at small facilities without heavy shielding. The final goal is that the linac and laser are installed on the moving gantry. We have designed the X-band (11.424 GHz) traveling-wave-type linac for the purpose. Numerical consideration by CAIN code and luminosity calculation are performed to estimate the X-ray yield. X-band thermionic-cathode RF-gun and RDS(Round Detuned Structure)-type X-band accelerating structure are applied to generate 50 MeV electron beam with 20 pC microbunches (104) for 1 microsecond RF macro-pulse. The X-ray yield by the electron beam and Q-switch Nd:YAG laser of 2 J/10 ns is 107 photons/RF-pulse (108 photons/sec at 10 pps). We design to adopt a technique of laser circulation to increase the X-ray yield up to 109 photons/pulse (1010 photons/s). 50 MW X-band klystron and compact modulator have been constructed and now under tuning. The construction of the whole system has started. X-ray generation and medical application will be performed in the early next year

X-band RF gun and linac for medical Compton scattering X-ray source

Science.gov (United States)

Dobashi, Katsuhito; Uesaka, Mitsuru; Fukasawa, Atsushi; Sakamoto, Fumito; Ebina, Futaro; Ogino, Haruyuki; Urakawa, Junji; Higo, Toshiyasu; Akemoto, Mitsuo; Hayano, Hitoshi; Nakagawa, Keiichi

2004-12-01

Compton scattering hard X-ray source for 10-80 keV are under construction using the X-band (11.424 GHz) electron linear accelerator and YAG laser at Nuclear Engineering Research laboratory, University of Tokyo. This work is a part of the national project on the development of advanced compact medical accelerators in Japan. National Institute for Radiological Science is the host institute and U.Tokyo and KEK are working for the X-ray source. Main advantage is to produce tunable monochromatic hard (10-80 keV) X-rays with the intensities of 108-1010 photons/s (at several stages) and the table-top size. Second important aspect is to reduce noise radiation at a beam dump by adopting the deceleration of electrons after the Compton scattering. This realizes one beamline of a 3rd generation SR source at small facilities without heavy shielding. The final goal is that the linac and laser are installed on the moving gantry. We have designed the X-band (11.424 GHz) traveling-wave-type linac for the purpose. Numerical consideration by CAIN code and luminosity calculation are performed to estimate the X-ray yield. X-band thermionic-cathode RF-gun and RDS(Round Detuned Structure)-type X-band accelerating structure are applied to generate 50 MeV electron beam with 20 pC microbunches (104) for 1 microsecond RF macro-pulse. The X-ray yield by the electron beam and Q-switch Nd:YAG laser of 2 J/10 ns is 107 photons/RF-pulse (108 photons/sec at 10 pps). We design to adopt a technique of laser circulation to increase the X-ray yield up to 109 photons/pulse (1010 photons/s). 50 MW X-band klystron and compact modulator have been constructed and now under tuning. The construction of the whole system has started. X-ray generation and medical application will be performed in the early next year.

Calculation of Nuclear Particles Production at High-Energy Photon Beams from a Linac Operating at 6, 10 and 15 MV.

Science.gov (United States)

Marchesini, Renato; Bettega, Daniela; Calzolari, Paola; Pignoli, Emanuele

2017-05-01

Production of photonuclear particles in a tissue-equivalent medium has been calculated for linacs at 6, 10 and 15 MV from Varian TrueBeam. Based on the knowledge of bremsstrahlung fluence spectra and linac photon beam parameters, numerical integration was performed on the cross sections for photoparticle production of the constituent elements of tissue (2H,12C,13C,16O,17O,18O,14N,15N). At 15 MV, at the depth of photon maximum dose, the total absorbed dose due to neutrons, protons, alphas and residual nuclei from photon reactions in tissue (5.5E-05 Gy per Gy of photons) is comparable to that due to neutrons from accelerator head. Results reasonably agree with data reported in the literature using Monte Carlo models simulating linac head components. This work suggests a simple method to estimate the dose contributed by the photon-induced nuclear particles for high-energy photon beams produced by linacs in use, as it might be relevant for late stochastic effects. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Proton induction linacs as high-intensity neutron sources

International Nuclear Information System (INIS)

Keefe, D.; Hoyer, E.

1981-01-01

Proton induction linacs are explored as high intensity neutron sources. The induction linac - concept, properties, experience with electrons, and possibilities - and its limitations for accelerating ions are reviewed. A number of proton induction linac designs are examined with the LIACEP program and general conclusions are given. Results suggest that a proton induction accelerator of the lowest voltage, consistent with good neutron flux, is preferred and could well be cost competitive with the usual rf linac/storage ring designs. (orig.)

Characterization of the Photon Energy Spectrum of a 6 MV Linac

International Nuclear Information System (INIS)

Hernandez Bojorquez, M.; Larraga, J. M.; Garcia, A.; Celis, M. A.; Martinez-Davalos, A.; Rodriguez-Villafuerte, M.

2006-01-01

In this work we study the influence of the purity of the materials used in experimental transmission measurements to obtain data to reconstruct the photon energy spectrum of a 6 MV Linac. We also evaluate the contribution to PDDs due to electron contamination in the reconstructed spectrum

The Pre-Injector Linac for the Diamond Light Source

CERN Document Server

Christou, C

2004-01-01

The Diamond Light Source is a new medium-energy high brightness synchrotron light facility which is under construction on the Rutherford Appleton Laboratory site in the U.K. The accelerator facility can be divided into three major components; a 3 GeV 561 m circumference storage ring, a full-energy booster synchrotron and a 100 MeV pre-injector linac. This paper describes the linac design and plans for operation. The linac is supplied by ACCEL Instruments GmbH under a turn-key contract, with Diamond Light Source Ltd. providing linac beam diagnostics, control system hardware and standard vacuum components. Commissioning of the linac will take place in early 2005 and user operation of the facility will commence in 2007.

H- ion sources for CERN's Linac4

Science.gov (United States)

Lettry, J.; Aguglia, D.; Coutron, Y.; Chaudet, E.; Dallocchio, A.; Gil Flores, J.; Hansen, J.; Mahner, E.; Mathot, S.; Mattei, S.; Midttun, O.; Moyret, P.; Nisbet, D.; O'Neil, M.; Paoluzzi, M.; Pasquino, C.; Pereira, H.; Arias, J. Sanchez; Schmitzer, C.; Scrivens, R.; Steyaert, D.

2013-02-01

The specifications set to the Linac4 ion source are: H- ion pulses of 0.5 ms duration, 80 mA intensity and 45 keV energy within a normalized emittance of 0.25 mmmrad RMS at a repetition rate of 2 Hz. In 2010, during the commissioning of a prototype based on H- production from the plasma volume, it was observed that the powerful co-extracted electron beam inherent to this type of ion source could destroy its electron beam dump well before reaching nominal parameters. However, the same source was able to provide 80 mA of protons mixed with a small fraction of H2+ and H3+ molecular ions. The commissioning of the radio frequency quadrupole accelerator (RFQ), beam chopper and H- beam diagnostics of the Linac4 are scheduled for 2012 and its final installation in the underground building is to start in 2013. Therefore, a crash program was launched in 2010 and reviewed in 2011 aiming at keeping the original Linac4 schedule with the following deliverables: Design and production of a volume ion source prototype suitable for 20-30 mA H- and 80 mA proton pulses at 45 keV by mid-2012. This first prototype will be dedicated to the commissioning of the low energy components of the Linac4. Design and production of a second prototype suitable for 40-50 mA H- based on an external RF solenoid plasma heating and cesiated-surface production mechanism in 2013 and a third prototype based on BNL's Magnetron aiming at reliable 2 Hz and 80 mA H- operations in 2014. In order to ease the future maintenance and allow operation with Ion sources based on three different production principles, an ion source "front end" providing alignment features, pulsed gas injection, pumping units, beam tuning capabilities and pulsed bipolar high voltage acceleration was designed and is being produced. This paper describes the progress of the Linac4 ion source program, the design of the Front end and first ion source prototype. Preliminary results of the summer 2012 commissioning are presented. The outlook on

Linac-driven spallation-neutron source

International Nuclear Information System (INIS)

Jason, A.J.

1995-01-01

Strong interest has arisen in accelerator-driven spallation-neutron sources that surpass existing facilities (such as ISIS at Rutherford or LANSCE at Los Alamos) by more than an order of magnitude in beam power delivered to the spallation target. The approach chosen by Los Alamos (as well as the European Spallation Source) provides the full beam energy by acceleration in a linac as opposed to primary acceleration in a synchrotron or other circular device. Two modes of neutron production are visualized for the source. A short-pulse mode produces 1 MW of beam power (at 60 pps) in pulses, of length less than 1 ms, by compression of the linac macropulse through multi-turn injection in an accumulator ring. A long-pulse mode produces a similar beam power with 1-ms-long pulses directly applied to a target. This latter mode rivals the performance of existing reactor facilities to very low neutron energies. Combination with the short-pulse mode addresses virtually all applications

Electro neutrons around a 12 MV Linac

International Nuclear Information System (INIS)

Vega C, H. R.; Perez L, L. H.

2012-10-01

Neutron contamination around Linacs for radiotherapy is a source of undesirable doses for the patient. The main source of these neutrons is the photonuclear reactions occurring in the Linac head and the patient body. Electrons also produce neutrons through (e, en) reactions. This reaction is known as electro disintegration and is carried out by the electron scattering that produce a virtual photon that is absorbed by the scattering nucleus producing the reaction e + A → (A-1) + n + e'. In this work the electron-neutron spectrum to 100 cm from the isocenter of a 12 MV Linac has been measured using a passive Bonner spheres spectrometer in a novel procedure named Planetary mode. (Author)

A 2--4 nm Linac Coherent Light Source (LCLS) using the SLAC linac

International Nuclear Information System (INIS)

Winick, H.; Bane, K.; Boyce, R.

1993-05-01

We describe the use of the SLAC linac to drive a unique, powerful. short wavelength Linac Coherent Light Source (LCLS). Operating as an FEL, lasing would be achieved in a single pass of a high peak current electron beam through a long undulator by self-amplified spontaneous emission (SASE). The main components are a high-brightness rf photocathode electron gun; pulse compressors; about 1/5 of the SLAC linac; and a long undulator with a FODO quadrupole focussing system. Using electrons below 8 GeV, the system would operate at wavelengths down to about 3 nm, producing ≥10 GW peak power in sub-ps pulses. At a 120 Hz rate the average power is ∼ 1 W

H- Ion Sources For CERN’s Linac4

CERN Document Server

Lettry, J; Coutron, Y; Chaudeta, E; Dallocchio, A; Gil Flores, J; Hansen, J; Mahner, E; Mathot, S; Mattei, S; Midttun, O; Moyret, P; Nisbet, D; O’Neil, M; Paoluzzi, M; Pasquino, C; Pereira, H; Sanchez Arias, J; Schmitzer, C; Scrivens, R; Steyaert, D

2013-01-01

The specifications set to the Linac4 ion source are: H- ion pulses of 0.5 ms duration, 80 mA intensity and 45 keV energy within a normalized emittance of 0.25 mmmrad RMS at a repetition rate of 2 Hz. In 2010, during the commissioning of a prototype based on H- production from the plasma volume, it was observed that the powerful co-extracted electron beam inherent to this type of ion source could destroy its electron beam dump well before reaching nominal parameters. However, the same source was able to provide 80 mA of protons mixed with a small fraction of H2+ and H3+ molecular ions. The commissioning of the radio frequency quadrupole accelerator (RFQ), beam chopper and H- beam diagnostics of the Linac4 are scheduled for 2012 and its final installation in the underground building is to start in 2013. Therefore, a crash program was launched in 2010 and reviewed in 2011 aiming at keeping the original Linac4 schedule with the following deliverables: Design and production of a volume ion source prototype suitabl...

Ion sources for induction linac driven heavy ion fusion

International Nuclear Information System (INIS)

Rutkowski, H.L.; Eylon, S.; Chupp, W.W.

1993-08-01

The use of ion sources in induction linacs for heavy ion fusion is fundamentally different from their use in the rf linac-storage rings approach. Induction linacs require very high current, short pulse extraction usually with large apertures which are dictated by the injector design. One is faced with the problem of extracting beams in a pulsed fashion while maintaining high beam quality during the pulse (low-emittance). Four types of sources have been studied for this application. The vacuum arc and the rf cusp field source are the plasma types and the porous plug and hot alumino-silicate surface source are the thermal types. The hot alumino-silicate potassium source has proved to be the best candidate for the next generation of scaled experiments. The porous plug for potassium is somewhat more difficult to use. The vacuum arc suffers from noise and lifetime problems and the rf cusp field source is difficult to use with very short pulses. Operational experience with all of these types of sources is presented

Ion sources for induction linac driven heavy ion fusion

International Nuclear Information System (INIS)

Rutkowski, H.L.; Eylon, S.; Chupp, W.W.

1994-01-01

The use of ion sources in induction linacs for heavy ion fusion is fundamentally different from their use in the rf linac-storage rings approach. Induction linacs require very high current, short pulse extraction usually with large apertures which are dictated by the injector design. One is faced with the problem of extracting beams in a pulsed fashion while maintaining high beam quality during the pulse (low emittance). Four types of sources have been studied for this application. The vacuum arc and the rf cusp field source are the plasma-types and the porous plug and hot alumino--silicate surface source are the thermal types. The hot alumino--silicate potassium source has proved to be the best candidate for the next generation of scaled experiments. The porous plug for potassium is somewhat more difficult to use. The vacuum arc suffers from noise and lifetime problems and the rf cusp field source is difficult to use with very short pulses. Operational experience with all of these types of sources is presented

FEL research and development at the SLAC sub-picosecond photon source, SPPS

International Nuclear Information System (INIS)

Bentson, L.; Bolton, P.; Bong, E.; Emma, P.; Galayda, J.; Hastings, J.; Krejcik, P.; Rago, C.; Rifkin, J.; Spencer, C.M.

2003-01-01

An upgrade project to the SLAC linac allows ultra-short electron bunches to be interleaved with the routine high-energy physics program operation, for use with an undulator to produce short-pulse, high-brightness X-rays. The linac upgrade comprises of the installation in the summer of 2002 of a bunch compressor chicane of similar design to the Linac Coherent Light Source (LCLS) project. A final compression stage in the high-energy Final Focus Test Beam (FFTB) line compresses the 28 GeV, 3.4 nC electron bunch to 80 fs FWHM, where a 5 m section of undulator (K=4.45) will produce 1.5 A X-rays with 3x10 7 photons per pulse and a peak brightness of 4x10 24 photons mm -2 mrad -2 s -1 (0.1% BW). The facility will allow us to test the dynamics and associated technology of bunch compression and gain valuable experience for the LCLS using the SLAC linac. New ultra-short electron bunch diagnostic techniques will be developed hand in hand with the same ultra-fast laser technology to be used for LCLS. Issues of high peak power (27 GW) X-ray transport and optics can be addressed at this facility as well as pump-probe and ultra-fast laser timing and stability issues

Parallel Beam Dynamics Simulation Tools for Future Light Source Linac Modeling

International Nuclear Information System (INIS)

Qiang, Ji; Pogorelov, Ilya v.; Ryne, Robert D.

2007-01-01

Large-scale modeling on parallel computers is playing an increasingly important role in the design of future light sources. Such modeling provides a means to accurately and efficiently explore issues such as limits to beam brightness, emittance preservation, the growth of instabilities, etc. Recently the IMPACT codes suite was enhanced to be applicable to future light source design. Simulations with IMPACT-Z were performed using up to one billion simulation particles for the main linac of a future light source to study the microbunching instability. Combined with the time domain code IMPACT-T, it is now possible to perform large-scale start-to-end linac simulations for future light sources, including the injector, main linac, chicanes, and transfer lines. In this paper we provide an overview of the IMPACT code suite, its key capabilities, and recent enhancements pertinent to accelerator modeling for future linac-based light sources

Concepts for a slow-positron target at the advanced photon source

International Nuclear Information System (INIS)

Lessner, E.; White, M.

1997-01-01

The Advanced Photon Source (APS) linear accelerator beam could be used to produce slow positrons during the hours between the storage ring injection cycles. Initial concepts for the design of a target that is optimized for slow-positron production are discussed, and simulation results are presented. Some possible ways to increase the nominal linac beam power for improved slow-positron production are also discussed

Partial discharge tests and characterisation of the Advanced Photon Source linac modulator cables

International Nuclear Information System (INIS)

Cours, A.

2007-01-01

The advanced photon source (APS) linac modulators are PFN-type pulsers with switch-mode charging power supplies (PSs). The PS and the PFN are connected to each other by 15 feet of 100-kV x-ray cable, with the PFN end of the cable terminated with a connector that was confirmed partial-discharge (PD)-free up to 38 kV ac (53.5 kV peak). Another end of the cable is terminated with a connector that was designed by the PS manufacturer and cannot easily be replaced with another type of connector, since part of it is located inside the densely packed PS. PD tests of the cables with this type of connector show that the PD inception voltages (PDIVs) in different cables turn out to be located within a wide voltage range: 21 to 27 kV ac that corresponds to 29 to 38 kV peak. In order to evaluate the insulation condition of the modulator cables, detect insulation deterioration, and ensure failure-preventing equipment maintenance, over the last two years the PDIVs of all high-voltage (HV) cables in use in the modulators have been tested about every three and a half months. Before the tests, all cables were removed from the equipment, carefully cleaned, inspected, and regreased. The tests were performed using a 40-kV PD detector. The test results show that: 1 The PDIVs remain almost unchanged in all tested cables. 2 From test to test, the PDIV of any particular cable may slightly oscillate around some average value. This possibly depends on the connector regreasing technique. 3 There is no direct evidence of cable insulation deterioration during more than two years of operation under voltage higher than the PD inception level.

A hot-spare injector for the APS linac

International Nuclear Information System (INIS)

Lewellen, J. W.

1999-01-01

Last year a second-generation SSRL-type thermionic cathode rf gun was installed in the Advanced Photon Source (APS) linac. This gun (referred to as ''gun2'') has been successfully commissioned and now serves as the main injector for the APS linac, essentially replacing the Koontz-type DC gun. To help ensure injector availability, particularly with the advent of top-up mode operation at the APS, a second thermionic-cathode rf gun will be installed in the APS linac to act as a hot-spare beam source. The hot-spare installation includes several unique design features, including a deep-orbit Panofsky-style alpha magnet. Details of the hot-spare beamline design and projected performance are presented, along with some plans for future performance upgrades

Compact quasi-monoenergetic photon sources from laser-plasma accelerators for nuclear detection and characterization

Energy Technology Data Exchange (ETDEWEB)

Geddes, Cameron G.R., E-mail: cgrgeddes@lbl.gov; Rykovanov, Sergey; Matlis, Nicholas H.; Steinke, Sven; Vay, Jean-Luc; Esarey, Eric H.; Ludewigt, Bernhard; Nakamura, Kei; Quiter, Brian J.; Schroeder, Carl B.; Toth, Csaba; Leemans, Wim P.

2015-05-01

Near-monoenergetic photon sources at MeV energies offer improved sensitivity at greatly reduced dose for active interrogation, and new capabilities in treaty verification, nondestructive assay of spent nuclear fuel and emergency response. Thomson (also referred to as Compton) scattering sources are an established method to produce appropriate photon beams. Applications are however restricted by the size of the required high-energy electron linac, scattering (photon production) system, and shielding for disposal of the high energy electron beam. Laser-plasma accelerators (LPAs) produce GeV electron beams in centimeters, using the plasma wave driven by the radiation pressure of an intense laser. Recent LPA experiments are presented which have greatly improved beam quality and efficiency, rendering them appropriate for compact high-quality photon sources based on Thomson scattering. Designs for MeV photon sources utilizing the unique properties of LPAs are presented. It is shown that control of the scattering laser, including plasma guiding, can increase photon production efficiency. This reduces scattering laser size and/or electron beam current requirements to scale compatible with the LPA. Lastly, the plasma structure can decelerate the electron beam after photon production, reducing the size of shielding required for beam disposal. Together, these techniques provide a path to a compact photon source system.

A Recirculating Linac-Based Facility for Ultrafast X-Ray Science

International Nuclear Information System (INIS)

Corlett, J. N.; Barletta, W. A.; DeSantis, S.; Doolittle, L.; Fawley, W. M.; Green, M.A.; Heimann, P.; Leone, S.; Lidia, S.; Li, D.; Ratti, A.; Robinson, K.; Schoenlein, R.; Staples, J.; Wan, W.; Wells, R.; Wolski, A.; Zholents, A.; Parmigiani, F.; Placidi, M.; Pirkl, W.; Rimmer, R. A.; Wang, S.

2003-01-01

We present an updated design for a proposed source of ultra-fast synchrotron radiation pulses based on a recirculating superconducting linac [1,2], in particular the incorporation of EUV and soft x-ray production. The project has been named LUX--Linac-based Ultrafast X-ray facility. The source produces intense x-ray pulses with duration of 10-100 fs at a 10 kHz repetition rate, with synchronization of 10's fs, optimized for the study of ultra-fast dynamics. The photon range covers the EUV to hard x-ray spectrum by use of seeded harmonic generation in undulators, and a specialized technique for ultra-short pulse photon production in the 1-10 keV range. High brightness rf photocathodes produce electron bunches which are optimized either for coherent emission in free electron lasers, or to provide a large x/y emittance ration and small vertical emittance which allows for manipulation to produce short-pulse hard x-rays. An injector linac accelerates the beam to 120 MeV, and is followed by f our passes through a 600-720 MeV recirculating linac. We outline the major technical components of the proposed facility

The source development lab linac at BNL

International Nuclear Information System (INIS)

Graves, W.S.; Johnson, E.D.

1996-12-01

A 210 MeV SLAC-type electron linac is currently under construction at BNL as part of the Source Development Laboratory. A 1.6 cell RF photoinjector is employed as the high brightness electron source which is excited by a frequency tripled Titanium:Sapphire laser. This linac will be used for several source development projects including a short bunch storage ring, and a series of FEL experiments based on the 10 m long NISUS undulator. The FEL will be operated as either a SASE or seeded beam device using the Ti:Sapp laser. For the seeded beam experiments; direct amplification, harmonic generation, and chirped pulse amplification modes will be studied, spanning an output wavelength range from 900 nm down to 100 nm. This paper presents the project's design parameters and results of recent modeling using the PARMELA and MAD simulation codes

A photon source model based on particle transport in a parameterized accelerator structure for Monte Carlo dose calculations.

Science.gov (United States)

Ishizawa, Yoshiki; Dobashi, Suguru; Kadoya, Noriyuki; Ito, Kengo; Chiba, Takahito; Takayama, Yoshiki; Sato, Kiyokazu; Takeda, Ken

2018-05-17

An accurate source model of a medical linear accelerator is essential for Monte Carlo (MC) dose calculations. This study aims to propose an analytical photon source model based on particle transport in parameterized accelerator structures, focusing on a more realistic determination of linac photon spectra compared to existing approaches. We designed the primary and secondary photon sources based on the photons attenuated and scattered by a parameterized flattening filter. The primary photons were derived by attenuating bremsstrahlung photons based on the path length in the filter. Conversely, the secondary photons were derived from the decrement of the primary photons in the attenuation process. This design facilitates these sources to share the free parameters of the filter shape and be related to each other through the photon interaction in the filter. We introduced two other parameters of the primary photon source to describe the particle fluence in penumbral regions. All the parameters are optimized based on calculated dose curves in water using the pencil-beam-based algorithm. To verify the modeling accuracy, we compared the proposed model with the phase space data (PSD) of the Varian TrueBeam 6 and 15 MV accelerators in terms of the beam characteristics and the dose distributions. The EGS5 Monte Carlo code was used to calculate the dose distributions associated with the optimized model and reference PSD in a homogeneous water phantom and a heterogeneous lung phantom. We calculated the percentage of points passing 1D and 2D gamma analysis with 1%/1 mm criteria for the dose curves and lateral dose distributions, respectively. The optimized model accurately reproduced the spectral curves of the reference PSD both on- and off-axis. The depth dose and lateral dose profiles of the optimized model also showed good agreement with those of the reference PSD. The passing rates of the 1D gamma analysis with 1%/1 mm criteria between the model and PSD were 100% for 4�

Optical laser systems at the Linac Coherent Light Source

Energy Technology Data Exchange (ETDEWEB)

Minitti, Michael P.; Robinson, Joseph S.; Coffee, Ryan N.; Edstrom, Steve; Gilevich, Sasha; Glownia, James M.; Granados, Eduardo; Hering, Philippe; Hoffmann, Matthias C.; Miahnahri, Alan; Milathianaki, Despina; Polzin, Wayne; Ratner, Daniel; Tavella, Franz; Vetter, Sharon; Welch, Marc; White, William E.; Fry, Alan R., E-mail: alanfry@slac.stanford.edu [Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)

2015-04-22

This manuscript serves as a reference to describe the optical laser sources and capabilities at the Linac Coherent Light Source. Ultrafast optical lasers play an essential role in exploiting the unique capabilities of recently commissioned X-ray free-electron laser facilities such as the Linac Coherent Light Source (LCLS). Pump–probe experimental techniques reveal ultrafast dynamics in atomic and molecular processes and reveal new insights in chemistry, biology, material science and high-energy-density physics. This manuscript describes the laser systems and experimental methods that enable cutting-edge optical laser/X-ray pump–probe experiments to be performed at LCLS.

Mechanical Engineering of the Linac for the Spallation Neutron Source

International Nuclear Information System (INIS)

Bultman, N.K.; Chen, Z.; Collier, M.; Erickson, J.L.; Guthrie, A.; Hunter, W.T.; Ilg, T.; Meyer, R.K.; Snodgrass, N.L.

1999-01-01

The linac for the Spallation Neutron Source (SNS) Project will accelerate an average current of 1 mA of H - ions from 20 MeV to 1GeV for injection into an accumulator ring. The linac will be an intense source of H - ions and as such requires advanced design techniques to meet project technical goals as well as to minimize costs. The DTL, CCDTL and CCL are 466m long and operate at 805 MHz with a maximum H - input current of 28 mA and 7% rf duty factor. The Drift Tube Linac is a copper-plated steel structure using permanent magnetic quadrupoles. The Coupled-Cavity portions are brazed copper structures and use electromagnetic quads. RF losses in the copper are 80 MW, with total rf power supplied by 52 klystrons. Additionally, the linac is to be upgraded to the 2- and 4-MW beam power levels with no increase in duty factor. The authors give an overview of the linac mechanical engineering effort and discuss the special challenges and status of the effort

Preinjector for Linac 1, ion source

CERN Multimedia

1974-01-01

For a description of the Linac 1 preinjector, please see first 7403070X. Inside the drum-shaped container shown in 7403081X, is the ion source with its associated electronics. It sits at the HV end of the accelerating column seen also in 7403081.

Linac Coherent Light Source (LCLS) Design Study Report

Energy Technology Data Exchange (ETDEWEB)

Cornacchia, Massimo

1998-12-04

The Stanford Linear Accelerator Center, in collaboration with Los Alamos National Laboratory, Lawrence Livermore National Laboratory, and the University of California at Los Angeles, is proposing to build a Free-Electron-Laser (FEL) R and D facility operating in the wavelength range 1.5-15 {angstrom}. This FEL, called the ''Linac Coherent Light Source'' (LCLS), utilizes the SLAC linac and produces sub-picosecond pulses of short wavelength x-rays with very high peak brightness and full transverse coherence. Starting in FY 1998, the first two-thirds of the SLAC linac will be used for injection into the B factory. This leaves the last one-third free for acceleration to 15 GeV. The LCLS takes advantage of this opportunity, opening the way for the next generation of synchrotron light sources with largely proven technology and cost effective methods. This proposal is consistent with the recommendations of the Report of the Basic Energy Sciences Advisory Committee (Synchrotron Radiation Light Source Working Group, October 18-19, 1997). The report recognizes that ''fourth-generation x-ray sources...will in all likelihood be based on the free electron laser concepts. If successful, this technology could yield improvements in brightness by many orders of magnitude.'' This Design Study, the authors believe, confirms the feasibility of constructing an x-ray FEL based on the SLAC linac. Although this design is based on a consistent and feasible set of parameters, some components require more research and development to guarantee the performance. Given appropriate funding, this R and D phase can be completed in 2 years.

Status and Operation of the Linac4 Ion Source Prototypes

CERN Document Server

Lettry, J; Andersson, P; Bertolo, S; Butterworth, A; Coutron, Y; Dallocchio, A; Chaudet, E; Gil-Flores, J; Guida, R; Hansen, J; Hatayama, A; Koszar, I; Mahner, E; Mastrostefano, C; Mathot, S; Mattei, S; Midttun, O; Moyret, P; Nisbet, D; Nishida, K; O’Neil, M; Ohta, M; Paoluzzi, M; Pasquino, C; Pereira, H; Rochez, J; Sanchez Alvarez, J; Sanchez Arias, J; Scrivens, R; Shibata, T; Steyaert, D; Thaus, N; Yamamoto, T

2014-01-01

CERN’s Linac4 45 kV H- ion sources prototypes are installed at a dedicated ion source test stand and in the Linac4 tunnel. The operation of the pulsed hydrogen injection, RF sustained plasma and pulsed high voltages are described. The first experimental results of two prototypes relying on 2MHz RF- plasma heating are presented. The plasma is ignited via capacitive coupling, and sustained by inductive coupling. The light emitted from the plasma is collected by viewports pointing to the plasma chamber wall in the middle of the RF solenoid and to the plasma chamber axis. Preliminary measurements of optical emission spectroscopy and photometry of the plasma have been performed. The design of a cesiated ion source is presented. The volume source has produced a 45 keV H- beam of 16-22 mA which has successfully been used for the commissioning of the Low Energy Beam Transport (LEBT), Radio Frequency Quadrupole (RFQ) accelerator and chopper of Linac4.

Performance of the advanced photon source (APS) linac beam position monitors (BPMs) with logarithmic amplifier electronics

International Nuclear Information System (INIS)

Fuja, R.E.; White, M.

1995-01-01

This paper discusses the performance of the logarithmic amplifier electronics system used with stripline BPMs to measure electron and positron beam positions at the APS linac. The 2856-MHz, S-band linac accelerates 30-nsec pulses of 1.7 A of electrons to 200 MeV, and focuses them onto a positron conversion target. The resulting 8 mA of positrons are further accelerated to 450 MeV by the positron linac. Beam position resolutions of 50 μm are easily obtainable in both the electron and positron linacs. The resolution of the 12-bit A/D converters limits the ultimate beam positron resolution to between 20 and 30 μm at this time

Impact of Monoenergetic Photon Sources on Nonproliferation Applications Final Report

Energy Technology Data Exchange (ETDEWEB)

Geddes, Cameron [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ludewigt, Bernhard [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Valentine, John [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Quiter, Brian [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Descalle, Marie-Anne [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Warren, Glen [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kinlaw, Matt [Idaho National Lab. (INL), Idaho Falls, ID (United States); Thompson, Scott [Idaho National Lab. (INL), Idaho Falls, ID (United States); Chichester, David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Miller, Cameron [Univ. of Michigan, Ann Arbor, MI (United States); Pozzi, Sara [Univ. of Michigan, Ann Arbor, MI (United States)

2017-03-01

Near-monoenergetic photon sources (MPSs) have the potential to improve sensitivity at greatly reduced dose in existing applications and enable new capabilities in other applications, particularly where passive signatures do not penetrate or are insufficiently accurate. MPS advantages include the ability to select energy, energy spread, flux, and pulse structures to deliver only the photons needed for the application, while suppressing extraneous dose and background. Some MPSs also offer narrow angular divergence photon beams which can target dose and/or mitigate scattering contributions to image contrast degradation. Current bremsstrahlung photon sources (e.g., linacs and betatrons) produce photons over a broad range of energies, thus delivering unnecessary dose that in some cases also interferes with the signature to be detected and/or restricts operations. Current sources must be collimated (reducing flux) to generate narrow divergence beams. While MPSs can in principle resolve these issues, they remain at relatively low TRL status. Candidate MPS technologies for nonproliferation applications are now being developed, each of which has different properties (e.g. broad vs. narrow angular divergence). Within each technology, source parameters trade off against one another (e.g. flux vs. energy spread), representing a large operation space. This report describes a broad survey of potential applications, identification of high priority applications, and detailed simulations addressing those priority applications. Requirements were derived for each application, and analysis and simulations were conducted to define MPS parameters that deliver benefit. The results can inform targeting of MPS development to deliver strong impact relative to current systems.

Overview of the advanced photon source (APS)

International Nuclear Information System (INIS)

White, M.M.

1994-01-01

The Advanced Photon Source (APS) is a state-of-the-art synchrotron light source facility dedicated to the production of extremely brilliant x-ray beams for research. Its super-intense x-ray beams will be used in many areas of research including industrial research, biological and medical research, defense-related research, and basic research. The APS x-ray beams will allow scientists to study smaller samples, more complex systems, faster reactions and processes, and gather data at a greater level of detail than has been possible to date. Creation of these beams begins with electron production by an electron gun with a thermionic cathode. The electrons are accelerated to 200 MeV by a linear accelerator (linac) and then impinge on a tungsten target, resulting in electron-positron pair production. The positrons are accelerated to 450 MeV in the remainder of the linac, then accumulated, damped, and transferred to a synchrotron that increases their energy to 7 GeV. The 7-GeV positrons are injected into a storage ring, where they pass through special magnets that cause them to emit x-rays of the desired quality. Construction at ANL is nearly complete at this time, and the APS will begin operating for users in 1996. The accelerator and experimental facilities are described in this paper, and a brief overview of some of the experimental programs is given

RESONANCE CONTROL FOR THE COUPLED CAVITY LINAC AND DRIFT TUBE LINAC STRUCTURES OF THE SPALLATION NEUTRON SOURCE LINAC USING A CLOSED-LOOP WATER COOLING SYSTEM

International Nuclear Information System (INIS)

Bernardin, J.D.; Brown, R.L.

2001-01-01

The Spallation Neutron Source (SNS) is a facility being designed for scientific and industrial research and development. SNS will generate and use neutrons as a diagnostic tool for medical purposes, material science, etc. The neutrons will be produced by bombarding a heavy metal target with a high-energy beam of protons, generated and accelerated with a linear particle accelerator, or linac. The low energy end of the linac consists of two room temperature copper structures, the drift tube linac (DTL), and the coupled cavity linac (CCL). Both of these accelerating structures use large amounts of electrical energy to accelerate the protons to an energy of 185 MeV. Approximately 60-80% of the electrical energy is dissipated in the copper structure and must be removed. This is done using specifically designed water cooling passages within the linac's copper structure. Cooling water is supplied to these cooling passages by specially designed resonance control and water cooling systems

Free electron laser facilities employing a 150-MeV linac injector for Saga synchrotron light source

International Nuclear Information System (INIS)

Tomimasu, T.; Yasumoto, M.; Ochiai, Y.; Ishibashi, M.; Murayama, T.

1999-01-01

Free electron laser (FEL) facilities as the FELI FEL Facility are proposed, for which a 150-MeV linac type injector for a Saga synchrotron light source (SLS) is employed in FEL mode. The linac has two operating modes; short macropulse mode a 1 μs at 150 MeV for injection to a 1 - 1.3-GeV third generation type storage ring and long macropulse mode of 12 μs at 100 MeV for four FEL Facilities. The macropulse beam consists of a train of several ps, 0.6 nC microbunches (peak current 100 A) repeating at 89.25 MHz. We are aiming to supply high power level photon beams covering an attractive wavelength range from 0.05 nm (25 keV) to 200 μm (0.006 eV) for scientific researches, bio-medical and industrial applications, using the Saga third generation type SLS with a superconducting wiggler and the proposed four FEL Facilities. (author)

Linac Coherent Light Source (LCLS) Conceptual Design Report

Energy Technology Data Exchange (ETDEWEB)

Nuhn, Heinz-Dieter

2002-11-25

The Stanford Linear Accelerator Center, in collaboration with Argonne National Laboratory, Brookhaven National Laboratory, Los Alamos National Laboratory, Lawrence Livermore National Laboratory, and the University of California at Los Angeles, have collaborated to create a conceptual design for a Free-Electron-Laser (FEL) R&D facility operating in the wavelength range 1.5-15 {angstrom}. This FEL, called the ''Linac Coherent Light Source'' (LCLS), utilizes the SLAC linac and produces sub-picosecond pulses of short wavelength x-rays with very high peak brightness and full transverse coherence. The first two-thirds of the SLAC linac are used for injection into the PEP-II storage rings. The last one-third will be converted to a source of electrons for the LCLS. The electrons will be transported to the SLAC Final Focus Test Beam (FFTB) Facility, which will be extended to house a 122-m undulator system. In passing through the undulators, the electrons will be bunched by the force of their own synchrotron radiation to produce an intense, spatially coherent beam of x-rays, tunable in energy from 0.8 keV to 8 keV. The LCLS will include two experiment halls as well as x-ray optics and infrastructure necessary to make use of this x-ray beam for research in a variety of disciplines such as atomic physics, materials science, plasma physics and biosciences. This Conceptual Design Report, the authors believe, confirms the feasibility of constructing an x-ray FEL based on the SLAC linac.

Photons and photoneutrons spectra of a Linac of 15 MV

International Nuclear Information System (INIS)

Benites R, J. L.; Carrillo C, A.; Vega C, H. R.; Velazquez F, J. B.

2011-10-01

Using the Monte Carlo code MCNP-5, the photons and photoneutrons spectra generated in the head stock of the lineal accelerator (Linac) Varian of 15 MV of the Cancerology State of Nayarit were determined. For the calculations a heterogeneous head stock was modeled, more compatible with the work conditions. In the center of the head stock a tungsten target was located on a copper support, followed by the flattened filter. The photons and photoneutrons spectra were obtained accelerating electrons and making them collide against the target to produce photons by Bremsstrahlung, these photons were transported inside the head stock and the photons and photoneutrons spectra were calculated in a punctual detector located under the flattened filter and in the isocenter. The spectra were evaluated in punctual detectors that were located in the plane from the isocenter to the long of the X and Y axes each 20 cm, in an equidistant way, up to 2 m, so much in the longitudinal and transversal axes. In the calculations were used histories 5E(6) with the purpose of obtaining smaller uncertainties to 1%. It was found that the photons spectrum in the punctual detector inside the head stock presents a pick of 1.25 MeV in the energy interval of 0.5 and 1.5 MeV, later suffers a filtration and diminishes in asymptote form. This spectrum modifies when the beam reaches the isocenter, diminishing the low energy photons. Inside the head stock the photoneutrons spectrum shows a structure with two picks, one before 1 MeV and other after 1 MeV; this is for effect of the collimators geometry and the distance. Finally an increment of the total neutrons flow to 60 cm of distance of the isocenter on the Y axis was observed, due to the design geometry of the modeling heterogeneous head stock. (Author)

Advanced photon source low-energy undulator test line

International Nuclear Information System (INIS)

Milton, S.V.

1997-01-01

The injector system of the Advanced Photon Source (APS) consists of a linac capable of producing 450-MeV positrons or > 650-MeV electrons, a positron accumulator ring (PAR), and a booster synchrotron designed to accelerate particles to 7 GeV. There are long periods of time when these machines are not required for filling the main storage ring and instead can be used for synchrotron radiation research. We describe here an extension of the linac beam transport called the Low-Energy Undulator Test Line (LEUTL). The LEUTL will have a twofold purpose. The first is to fully characterize innovative, future generation undulators, some of which may prove difficult or impossible to measure by traditional techniques. These might include small-gap and superconducting undulators, very long undulators, undulators with designed-in internal focusing, and helical undulators. This technique also holds the promise of extending the magnetic measurement sensitivity beyond that presently attainable. This line will provide the capability to directly test undulators before their possible insertion into operating storage rings. A second use for the test line will be to investigate the generation of coherent radiation at wavelengths down to a few tens of nanometers

Calibration of an advanced photon source linac beam position monitor used for positron position measurement of a beam containing both positrons and electrons

International Nuclear Information System (INIS)

Sereno, Nicholas S.

1998-01-01

The Advanced Photon Source (APS) linac beam position monitors can be used to monitor the position of a beam containing both positrons and electrons. To accomplish this task, both the signal at the bunching frequency of 2856 MHz and the signal at 2x2856 MHz are acquired and processed for each stripline. The positron beam position is obtained by forming a linear combination of both 2856 and 5712 MHz signals for each stripline and then performing the standard difference over sum computation. The required linear combination of the 2856 and 5712 MHz signals depends on the electrical calibration of each stripline/cable combination. In this paper, the calibration constants for both 2856 MHz and 5712 MHz signals for each stripline are determined using a pure beam of electrons. The calibration constants are obtained by measuring the 2856 and 5712 MHz stripline signals at various electron beam currents and positions. Finally, the calibration constants measured using electrons are used to determine positron beam position for the mixed beam case

Linac4 H− ion sources

International Nuclear Information System (INIS)

Lettry, J.; Aguglia, D.; Andersson, P.; Bertolo, S.; Butterworth, A.; Coutron, Y.; Dallocchio, A.; David, N.; Chaudet, E.; Fink, D. A.; Garlasche, M.; Grudiev, A.; Guida, R.; Hansen, J.; Haase, M.; Jones, A.; Koszar, I.; Lallement, J.-B.; Lombardi, A. M.; Machado, C.

2016-01-01

CERN’s 160 MeV H − linear accelerator (Linac4) is a key constituent of the injector chain upgrade of the Large Hadron Collider that is being installed and commissioned. A cesiated surface ion source prototype is being tested and has delivered a beam intensity of 45 mA within an emittance of 0.3 π ⋅ mm ⋅ mrad. The optimum ratio of the co-extracted electron- to ion-current is below 1 and the best production efficiency, defined as the ratio of the beam current to the 2 MHz RF-power transmitted to the plasma, reached 1.1 mA/kW. The H − source prototype and the first tests of the new ion source optics, electron-dump, and front end developed to minimize the beam emittance are presented. A temperature regulated magnetron H − source developed by the Brookhaven National Laboratory was built at CERN. The first tests of the magnetron operated at 0.8 Hz repetition rate are described

A status update on the Advanced Photon Source Project--Summer 1993

International Nuclear Information System (INIS)

Moncton, D.E.; Fenner, R.B.

1993-01-01

The Advanced Photon Source Project has passed the mid-point in its construction. The linac and synchrotron booster enclosures are complete. A portion of the experiment hall has been completed and put into use to support accelerator component assembly, test, and installation. Plans for the user lab/office modules and the central laboratory/office complex are well advanced. Installation of the linac injection system has been completed and commissioning is beginning. Installation and commissioning of the positron accumulator ring, the booster synchrotron, the storage ring, and the rf power systems will follow. Accelerator operations capable of supporting the commissioning of the experimental beamlines is planned for the summer of 1995. A strong research program is continuing to produce results supportive of both accelerator and beamline construction and operations. Collaborative Access Teams have been formed to conduct research with the initial set of 32 beamlines that will be available at the completion of the first phase of construction

CERN’s Linac4 H− sources: Status and operational results

International Nuclear Information System (INIS)

Lettry, J.; Aguglia, D.; Andersson, P.; Bertolo, S.; Butterworth, A.; Coutron, Y.; Dallocchio, A.; David, N.; Chaudet, E.; Fink, D.; Gil-Flores, J.; Garlasche, M.; Grudiev, A.; Guida, R.; Hansen, J.; Haase, M.; Jones, A.; Koszar, I.; Machado, C.; Mastrostefano, C.

2015-01-01

Two volume sources equipped with DESY and CERN plasma generators and a low voltage electron dump were operated at 45 kV in the Linac4 tunnel and on a dedicated test stand. These volume sources delivered approximately 20 mA and ensured the commissioning of the Radio Frequency Quadrupole accelerator and of the first section of the Drift Tube Linac. CERN’s prototype of a cesiated surface source equipped with this electron dump was operated continuously from November 2013 to April 2014 on the ion source test stand and is being commissioned in the Linac4 tunnel. Before cesiation, the prototype conditioned in volume mode provided up to 30 mA H − beam. Short cesiations, of the order of 10 mg effectively reduced the intensity of co-extracted electrons down to 2 - 8 times the H − current; this cesiated surface operation mode delivered up to 60 mA H − beam. An H − beam of the order of 40 mA was sustained up to four weeks operation with 500 μs pulses at 1.2s spacing. A new extraction was designed to match these beam properties. A copy of BNL’s magnetron produced at CERN was tested at BNL and delivered at 40 kV H − beam exceeding Linac4’s nominal intensity of 80 mA. In this contribution, the performances, dynamic response to cesiation, stability and availability of these prototypes are described. The needed optimization of the emittance of H − beam above 40 mA is presented, which requires an evolution of the front end that encompasses implementation of a large ceramic insulator

X-ray detectors at the Linac Coherent Light Source

International Nuclear Information System (INIS)

Blaj, Gabriel; Caragiulo, Pietro; Carini, Gabriella; Carron, Sebastian; Dragone, Angelo; Freytag, Dietrich; Haller, Gunther; Hart, Philip; Hasi, Jasmine; Herbst, Ryan; Herrmann, Sven; Kenney, Chris; Markovic, Bojan; Nishimura, Kurtis; Osier, Shawn; Pines, Jack; Reese, Benjamin; Segal, Julie; Tomada, Astrid; Weaver, Matt

2015-01-01

This paper offers an overview of area detectors developed for use at the Linac Coherent Light Source (LCLS) with particular emphasis on their impact on science. The experimental needs leading to the development of second-generation cameras for LCLS are discussed and the new detector prototypes are presented. Free-electron lasers (FELs) present new challenges for camera development compared with conventional light sources. At SLAC a variety of technologies are being used to match the demands of the Linac Coherent Light Source (LCLS) and to support a wide range of scientific applications. In this paper an overview of X-ray detector design requirements at FELs is presented and the various cameras in use at SLAC are described for the benefit of users planning experiments or analysts looking at data. Features and operation of the CSPAD camera, which is currently deployed at LCLS, are discussed, and the ePix family, a new generation of cameras under development at SLAC, is introduced

Reliability model of SNS linac (spallation neutron source-ORNL)

International Nuclear Information System (INIS)

Pitigoi, A.; Fernandez, P.

2015-01-01

A reliability model of SNS LINAC (Spallation Neutron Source at Oak Ridge National Laboratory) has been developed using risk spectrum reliability analysis software and the analysis of the accelerator system's reliability has been performed. The analysis results have been evaluated by comparing them with the SNS operational data. This paper presents the main results and conclusions focusing on the definition of design weaknesses and provides recommendations to improve reliability of the MYRRHA ( linear accelerator. The reliability results show that the most affected SNS LINAC parts/systems are: 1) SCL (superconducting linac), front-end systems: IS, LEBT (low-energy beam transport line), MEBT (medium-energy beam transport line), diagnostics and controls; 2) RF systems (especially the SCL RF system); 3) power supplies and PS controllers. These results are in line with the records in the SNS logbook. The reliability issue that needs to be enforced in the linac design is the redundancy of the systems, subsystems and components most affected by failures. For compensation purposes, there is a need for intelligent fail-over redundancy implementation in controllers. Enough diagnostics has to be implemented to allow reliable functioning of the redundant solutions and to ensure the compensation function

Commissioning the Linac Coherent Light Source injector

Directory of Open Access Journals (Sweden)

R. Akre

2008-03-01

Full Text Available The Linac Coherent Light Source is a SASE x-ray free-electron laser (FEL project presently under construction at SLAC [J. Arthur et al., SLAC-R-593, 2002.]. The injector section, from drive laser and rf photocathode gun through first bunch compressor chicane, was installed in the fall of 2006. The initial system commissioning with an electron beam was completed in August of 2007, with the goal of a 1.2-micron emittance in a 1-nC bunch demonstrated. The second phase of commissioning, including second bunch compressor and full linac, is planned for 2008, with FEL commissioning in 2009. We report experimental results and experience gained in the first phase of commissioning, including the photocathode drive laser, rf gun, photocathode, S-band and X-band rf systems, first bunch compressor, and the various beam diagnostics.

A Monte Carlo Study of the Photon Spectrum due to the Different Materials Used in the Construction of Flattening Filters of LINAC

Directory of Open Access Journals (Sweden)

J. S. Estepa Jiménez

2017-01-01

Full Text Available Different types the spectrum of photons were studied; they were emitted from the flattening filter of a LINAC Varian 2100 C/D that operates at 15 MV. The simplified geometry of the LINAC head was calculated using the MCNPX code based on the studies of the materials of the flattening filter, namely, SST, W, Pb, Fe, Ta, Al, and Cu. These materials were replaced in the flattening filter to calculate the photon spectra at the output of this device to obtain the spectrum that makes an impact with the patient. The different spectra obtained were analyzed and compared to the emission from the original spectra configuration of the LINAC, which uses material W. In the study, different combinations of materials were considered in order to establish differences between the use of different materials and the original material, with the objective of establishing advantages and disadvantages from a clinical standpoint.

Linac design study for an intense neutron-source driver

International Nuclear Information System (INIS)

Lynch, M.T.; Browman, A.; DeHaven, R.; Jameson, R.; Jason, A.; Neuschaefer, G.; Tallerico, P.; Regan, A.

1993-01-01

The 1-MW spallation-neutron source under design study at Los Alamos is driven by a linac-compressor-ring scheme that utilizes a large portion of the existing Los Alamos Meson Physics Facility (LAMPF) linac, as well as the facility infrastructure. The project is referred to as the National Center for Neutron Research (NCNR). A second phase of the proposal will upgrade the driver power to 5 MW. A description of the 1-MW scheme is given in this paper. In addition, the upgrade path to the substantial increase of beam power required for the 5 MW scenario is discussed

Photonic crystal light source

Science.gov (United States)

Fleming, James G [Albuquerque, NM; Lin, Shawn-Yu [Albuquerque, NM; Bur, James A [Corrales, NM

2004-07-27

A light source is provided by a photonic crystal having an enhanced photonic density-of-states over a band of frequencies and wherein at least one of the dielectric materials of the photonic crystal has a complex dielectric constant, thereby producing enhanced light emission at the band of frequencies when the photonic crystal is heated. The dielectric material can be a metal, such as tungsten. The spectral properties of the light source can be easily tuned by modification of the photonic crystal structure and materials. The photonic crystal light source can be heated electrically or other heating means. The light source can further include additional photonic crystals that exhibit enhanced light emission at a different band of frequencies to provide for color mixing. The photonic crystal light source may have applications in optical telecommunications, information displays, energy conversion, sensors, and other optical applications.

Source and LINAC3 studies

CERN Document Server

Bellodi, G

2017-01-01

In the framework of the LHC Ion Injector Upgrade pro-gramme (LIU), several activities have been carried out in2016 to improve the ion source and Linac3 performance,with the goal to increase the beam current routinely deliv-ered to LEIR. The extraction region of the GTS-LHC ionsource was upgraded with enlarged vacuum chamber aper-tures and the addition of an einzel lens, yielding highertransmission through the rest of the machine. Also, a seriesof experiments have been performed to study the effects ofdouble frequency mixing on the afterglow performance ofthe source after installation of a Travelling Wave Tube Am-plifier (TWTA) as secondary microwave source at variablefrequency. Measurements have been carried out at a dedi-cated oven test stand for better understanding of the ionsource performance. Finally, several MD sessions werededicated to the study and characterization of the strippingfoils, after evidence of degradation in time was discoveredin the 2015 run.

Microwave source development for 9 MeV RF electron LINAC for cargo scanning

International Nuclear Information System (INIS)

Yadav, V.; Chandan, Shiv; Tillu, A.R.; Bhattacharjee, D.; Chavan, R.B.; Dixit, K.P.; Mittal, K.C.; Gantayet, L.M.

2011-01-01

For cargo scanning, high energy X-rays are required. These X-rays can be generated from accelerated electrons. A 9 MeV Cargo scanning RF LINAC has been developed at ECIL, Hyderabad. The Microwave power source required for RF Linac is a klystron-based system generating 5.5 MW peak, 10 kW average, at 2.856 GHz. Various components required for microwave source were identified, procured, tested and integrated into the source. Microwave source was tested on water load, then it was connected to LINAC and RF conditioning and e-beam trials were successfully done. For operating the microwave source, a PC based remote handling system was also designed and developed for operating various power supplies and instruments of the microwave source, including the Klystron modulator, Signal generator and other devices. The accelerator operates in pulse mode, requiring synchronous operation of the Klystron modulator, RF driver amplifier and E-gun modulator. For this purpose, a synchronous trigger generator was designed and developed. This paper describes the development and testing of microwave source and its remote operating system. The results of beam trials are also discussed in this paper. (author)

Measuring linac photon beam energy through EPID image analysis of physically wedged fields

Energy Technology Data Exchange (ETDEWEB)

Dawoud, S. M., E-mail: samir.dawoud@leedsth.nhs.uk; Weston, S. J.; Bond, I.; Ward, G. C.; Rixham, P. A.; Mason, J.; Huckle, A. [Department of Medical Physics and Engineering, St. James Institute of Oncology, St. James University Hospital, Leeds LS9 7TF (United Kingdom); Sykes, J. R. [Institute of Medical Physics, School of Physics, The University of Sydney, New South Wales 2006, Australia and Department of Medical Physics and Engineering, St. James Institute of Oncology, St. James University Hospital, Leeds LS9 7TF (United Kingdom)

2014-02-15

Purpose: Electronic portal imaging devices (EPIDs) have proven to be useful tools for measuring several parameters of interest in linac quality assurance (QA). However, a method for measuring linac photon beam energy using EPIDs has not previously been reported. In this report, such a method is devised and tested, based on fitting a second order polynomial to the profiles of physically wedged beams, where the metric of interest is the second order coefficientα. The relationship between α and the beam quality index [percentage depth dose at 10 cm depth (PDD{sub 10})] is examined to produce a suitable calibration curve between these two parameters. Methods: Measurements were taken in a water-tank for beams with a range of energies representative of the local QA tolerances about the nominal value 6 MV. In each case, the beam quality was found in terms of PDD{sub 10} for 100 × 100 mm{sup 2} square fields. EPID images of 200 × 200 mm{sup 2} wedged fields were then taken for each beam and the wedge profile was fitted in MATLAB 2010b (The MathWorks, Inc., Natick, MA). α was then plotted against PDD{sub 10} and fitted with a linear relation to produce the calibration curve. The uncertainty in α was evaluated by taking five repeat EPID images of the wedged field for a beam of 6 MV nominal energy. The consistency of measuring α was found by taking repeat measurements on a single linac over a three month period. The method was also tested at 10 MV by repeating the water-tank crosscalibration for a range of energies centered approximately about a 10 MV nominal value. Finally, the calibration curve from the test linac and that from a separate clinical machine were compared to test consistency of the method across machines in a matched fleet. Results: The relationship betweenα and PDD{sub 10} was found to be strongly linear (R{sup 2} = 0.979) while the uncertainty in α was found to be negligible compared to that associated with measuring PDD{sub 10} in the water-tank (�

Single-photon sources

International Nuclear Information System (INIS)

Lounis, Brahim; Orrit, Michel

2005-01-01

The concept of the photon, central to Einstein's explanation of the photoelectric effect, is exactly 100 years old. Yet, while photons have been detected individually for more than 50 years, devices producing individual photons on demand have only appeared in the last few years. New concepts for single-photon sources, or 'photon guns', have originated from recent progress in the optical detection, characterization and manipulation of single quantum objects. Single emitters usually deliver photons one at a time. This so-called antibunching of emitted photons can arise from various mechanisms, but ensures that the probability of obtaining two or more photons at the same time remains negligible. We briefly recall basic concepts in quantum optics and discuss potential applications of single-photon states to optical processing of quantum information: cryptography, computing and communication. A photon gun's properties are significantly improved by coupling it to a resonant cavity mode, either in the Purcell or strong-coupling regimes. We briefly recall early production of single photons with atomic beams, and the operation principles of macroscopic parametric sources, which are used in an overwhelming majority of quantum-optical experiments. We then review the photophysical and spectroscopic properties and compare the advantages and weaknesses of various single nanometre-scale objects used as single-photon sources: atoms or ions in the gas phase and, in condensed matter, organic molecules, defect centres, semiconductor nanocrystals and heterostructures. As new generations of sources are developed, coupling to cavities and nano-fabrication techniques lead to improved characteristics, delivery rates and spectral ranges. Judging from the brisk pace of recent progress, we expect single photons to soon proceed from demonstrations to applications and to bring with them the first practical uses of quantum information

Photon factory activity report, 1993

International Nuclear Information System (INIS)

1994-01-01

This issue is the annual report of the Photon Factory, National Laboratory of High Energy Physics. First the outline of the Photon Factory is presented. Injector linac, light source, beamlines and instrumentation, synchrotron radiation facility at the Tristan accumulation ring, and the Tristan super light facility are described in detail. The facility is open to researchers. The user's reports are collected as well. (J.P.N.)

Improved beam extraction for a negative hydrogen ion source for the LHC injector chain upgrade, Linac4

CERN Document Server

Midttun, Øystein; Scrivens, Richard

In the scope of an upgrade of the injector chain of CERN’s accelerator complex, a new linear accelerator, Linac4, is under construction. This accelerator will replace the existing 50 MeV proton linac, Linac2. By increasing the beam energy to 160 MeV, Linac4 makes it possible to double the brightness in the PSB, and ultimately increase the luminosity in the LHC. Linac4 will accelerate beams of negative hydrogen (H-) to be injected into the PSB by multi-turn, charge exchange injection. The ion source was initially based on the non-caesiated RF-volume source from DESY. However, the beam extraction from this source could not handle the 45 keV beam energy required by the RFQ. A new beam extraction system has therefore been designed, via IBSimu simulations [1], to extract and transport the H- ion beam respecting the Linac4 requirements. Key features of the extraction system is a tuneable puller voltage to adapt the extraction field to the ion and electron beam currents, and a magnetized Einzel lens to dump the co...

MCMEG: Simulations of both PDD and TPR for 6 MV LINAC photon beam using different MC codes

International Nuclear Information System (INIS)

Fonseca, T.C.F.; Mendes, B.M.; Lacerda, M.A.S.; Silva, L.A.C.; Paixão, L.

2017-01-01

The Monte Carlo Modelling Expert Group (MCMEG) is an expert network specializing in Monte Carlo radiation transport and the modelling and simulation applied to the radiation protection and dosimetry research field. For the first inter-comparison task the group launched an exercise to model and simulate a 6 MV LINAC photon beam using the Monte Carlo codes available within their laboratories and validate their simulated results by comparing them with experimental measurements carried out in the National Cancer Institute (INCA) in Rio de Janeiro, Brazil. The experimental measurements were performed using an ionization chamber with calibration traceable to a Secondary Standard Dosimetry Laboratory (SSDL). The detector was immersed in a water phantom at different depths and was irradiated with a radiation field size of 10×10 cm 2 . This exposure setup was used to determine the dosimetric parameters Percentage Depth Dose (PDD) and Tissue Phantom Ratio (TPR). The validation process compares the MC calculated results to the experimental measured PDD20,10 and TPR20,10. Simulations were performed reproducing the experimental TPR20,10 quality index which provides a satisfactory description of both the PDD curve and the transverse profiles at the two depths measured. This paper reports in detail the modelling process using MCNPx, MCNP6, EGSnrc and Penelope Monte Carlo codes, the source and tally descriptions, the validation processes and the results. - Highlights: • MCMEG is an expert network specializing in Monte Carlo radiation transport. • MCNPx, MCNP6, EGSnrc and Penelope Monte Carlo codes are used. • Exercise to model and simulate a 6 MV LINAC photon beam using the Monte Carlo codes. • The PDD 20,10 and TPR 20,10 dosimetric parameters were compared with real data. • The paper reports in the modelling process using different Monte Carlo codes.

Spiraling contaminant electrons increase doses to surfaces outside the photon beam of an MRI-linac with a perpendicular magnetic field.

Science.gov (United States)

Hackett, Sara L; van Asselen, Bram; Wolthaus, Jochem W H; Bluemink, J J; Ishakoglu, Kübra; Kok, Jan G M; Lagendijk, Jan J W; Raaymakers, Bas W

2018-03-29

The transverse magnetic field of an MRI-linac sweeps contaminant electrons away from the radiation beam. Films oriented perpendicular to the magnetic field and 5cm from the radiation beam edge show a projection of the divergent beam, indicating that contaminant electrons spiral along magnetic field lines and deposit dose on surfaces outside the primary beam perpendicular to the magnetic field. These spiraling contaminant electrons (SCE) could increase skin doses to protruding regions of the patient along the cranio-caudal axis. This study investigated doses from SCE for an MRI-linac comprising a 7MV linac and a 1.5T MRI scanner. Surface doses to films perpendicular to the magnetic field and 5cm from the radiation beam edge showed increased dose within the projection of the primary beam, whereas films parallel to the magnetic field and 5cm from the beam edge showed no region of increased dose. However, the dose from contaminant electrons is absorbed within a few millimeters. For large fields, the SCE dose is within the same order of magnitude as doses from scattered and leakage photons. Doses for both SCE and scattered photons decrease rapidly with decreasing beam size and increasing distance from the beam edge. © 2018 Institute of Physics and Engineering in Medicine.

Photon factory activity report, 1992

International Nuclear Information System (INIS)

1993-01-01

This issue is the annual report of the Photon Factory, National laboratory of High Energy Physics. First, the outline of the Photon Factory is presented. Injector linac, light source, beamlines and instrumentation, the Tristan synchrotron radiation facility at the accumulation ring, and the Tristan super light facility are described in detail. The facility is open to researchers. The user's reports are collected as well. (J.P.N.) (435 refs.)

A 100 MeV linac for the SR light source

International Nuclear Information System (INIS)

Iwata, H.; Takahashi, T.; Kaneko, N.; Nakashizu, T.; Hara, O.

1992-01-01

A 4 m long linear accelerator has been designed to operate with the energy gain of 100 MeV and a beam current of 100 mA. It is scheduled to be installed into the compact synchrotron radiation light source (LUNA) in near future. In this report, several pre-tests and the design of this linac are discussed. High power testing by a 0.5 m long test linac shows that it takes 110 hr aging to reach no arcing condition at an electric field strength of 25 MeV/m. Another diffusion bonding test shows that it is possible to make the deformation less than 5μm per cell under optimum conditions of temperature and pressure. This linac is composed of 5 units, made by diffusion bonding. Each unit is bolted together to form a 4 m long linear accelerator. The entire assembly is placed within a cylinder which serves both as a vacuum envelope and as the support structure. (Author) 5 figs., 2 tabs

Diagnostic expert system in the PF LINAC

International Nuclear Information System (INIS)

Abe, Isamu; Nakahara, Kazuo; Kitamura, Masaharu.

1992-01-01

A prototype diagnostic expert system (ES) was developed for the Photon Factory 2.5-GeV electron/positron LINAC injector system. The ES has been on-lined with the conventional linac computer network for receiving real data. This project was undertaken in an attempt to reduce the linac operator's mental workload, diagnosis duties, and to explore Artificial Intelligence (AI) technologies. The outlook for ES and its problems, and what has been achieved are outlined in this presentation. (author)

Photons and photoneutrons spectra of a Linac of 15 MV; Espectros de fotones y fotoneutrones de un LINAC de 15 MV

Energy Technology Data Exchange (ETDEWEB)

Benites R, J. L.; Carrillo C, A. [Centro Estatal de Cancerologia de Nayarit, Av. Enfermeria, Fracc. Fray Junipero Serra, 63000 Tepic, Nayarit (Mexico); Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Velazquez F, J. B., E-mail: jlbenitesr@prodigy.net.mx [Universidad Autonoma de Nayarit, Posgrado CBAP, Carretera Tepic Compostela Km. 9, Xalisco, Nayarit (Mexico)

2011-10-15

Using the Monte Carlo code MCNP-5, the photons and photoneutrons spectra generated in the head stock of the lineal accelerator (Linac) Varian of 15 MV of the Cancerology State of Nayarit were determined. For the calculations a heterogeneous head stock was modeled, more compatible with the work conditions. In the center of the head stock a tungsten target was located on a copper support, followed by the flattened filter. The photons and photoneutrons spectra were obtained accelerating electrons and making them collide against the target to produce photons by Bremsstrahlung, these photons were transported inside the head stock and the photons and photoneutrons spectra were calculated in a punctual detector located under the flattened filter and in the isocenter. The spectra were evaluated in punctual detectors that were located in the plane from the isocenter to the long of the X and Y axes each 20 cm, in an equidistant way, up to 2 m, so much in the longitudinal and transversal axes. In the calculations were used histories 5E(6) with the purpose of obtaining smaller uncertainties to 1%. It was found that the photons spectrum in the punctual detector inside the head stock presents a pick of 1.25 MeV in the energy interval of 0.5 and 1.5 MeV, later suffers a filtration and diminishes in asymptote form. This spectrum modifies when the beam reaches the isocenter, diminishing the low energy photons. Inside the head stock the photoneutrons spectrum shows a structure with two picks, one before 1 MeV and other after 1 MeV; this is for effect of the collimators geometry and the distance. Finally an increment of the total neutrons flow to 60 cm of distance of the isocenter on the Y axis was observed, due to the design geometry of the modeling heterogeneous head stock. (Author)

Multi-photon absorption limits to heralded single photon sources

Science.gov (United States)

Husko, Chad A.; Clark, Alex S.; Collins, Matthew J.; De Rossi, Alfredo; Combrié, Sylvain; Lehoucq, Gaëlle; Rey, Isabella H.; Krauss, Thomas F.; Xiong, Chunle; Eggleton, Benjamin J.

2013-01-01

Single photons are of paramount importance to future quantum technologies, including quantum communication and computation. Nonlinear photonic devices using parametric processes offer a straightforward route to generating photons, however additional nonlinear processes may come into play and interfere with these sources. Here we analyse spontaneous four-wave mixing (SFWM) sources in the presence of multi-photon processes. We conduct experiments in silicon and gallium indium phosphide photonic crystal waveguides which display inherently different nonlinear absorption processes, namely two-photon (TPA) and three-photon absorption (ThPA), respectively. We develop a novel model capturing these diverse effects which is in excellent quantitative agreement with measurements of brightness, coincidence-to-accidental ratio (CAR) and second-order correlation function g(2)(0), showing that TPA imposes an intrinsic limit on heralded single photon sources. We build on these observations to devise a new metric, the quantum utility (QMU), enabling further optimisation of single photon sources. PMID:24186400

Neutron dose measurements of Varian and Elekta linacs by TLD600 and TLD700 dosimeters and comparison with MCNP calculations.

Science.gov (United States)

Nedaie, Hassan Ali; Darestani, Hoda; Banaee, Nooshin; Shagholi, Negin; Mohammadi, Kheirollah; Shahvar, Arjang; Bayat, Esmaeel

2014-01-01

High-energy linacs produce secondary particles such as neutrons (photoneutron production). The neutrons have the important role during treatment with high energy photons in terms of protection and dose escalation. In this work, neutron dose equivalents of 18 MV Varian and Elekta accelerators are measured by thermoluminescent dosimeter (TLD) 600 and TLD700 detectors and compared with the Monte Carlo calculations. For neutron and photon dose discrimination, first TLDs were calibrated separately by gamma and neutron doses. Gamma calibration was carried out in two procedures; by standard 60Co source and by 18 MV linac photon beam. For neutron calibration by (241)Am-Be source, irradiations were performed in several different time intervals. The Varian and Elekta linac heads and the phantom were simulated by the MCNPX code (v. 2.5). Neutron dose equivalent was calculated in the central axis, on the phantom surface and depths of 1, 2, 3.3, 4, 5, and 6 cm. The maximum photoneutron dose equivalents which calculated by the MCNPX code were 7.06 and 2.37 mSv.Gy(-1) for Varian and Elekta accelerators, respectively, in comparison with 50 and 44 mSv.Gy(-1) achieved by TLDs. All the results showed more photoneutron production in Varian accelerator compared to Elekta. According to the results, it seems that TLD600 and TLD700 pairs are not suitable dosimeters for neutron dosimetry inside the linac field due to high photon flux, while MCNPX code is an appropriate alternative for studying photoneutron production.

Overview of the Spallation Neutron Source Linac Low-Level RF Control System

CERN Document Server

Champion, Mark; Doolittle, Lawrence; Kasemir, Kay-Uwe; Ma, Hengjie; Piller, Maurice; Ratti, Alessandro

2005-01-01

The design and production of the Spallation Neutron Source Linac Low-Level RF control system is complete, and installation will be finished in Spring 2005. The warm linac beam commissioning run in Fall 2004 was the most extensive test to date of the LLRF control system, with fourteen (of an eventual 96) systems operating simultaneously. In this paper we present an overview of the LLRF control system, the experience in designing, building and installing the system, and operational results.

Vacuum simulation and characterization for the Linac4 H- source

Science.gov (United States)

Pasquino, C.; Chiggiato, P.; Michet, A.; Hansen, J.; Lettry, J.

2013-02-01

At CERN, the 160 MeV H- Linac4 will soon replace the 50 MeV proton Linac2. In the H- source two major sources of gas are identified. The first is the pulsed injection at about 0.1 mbar in the plasma chamber. The second is the constant H2 injection up to 10-5 mbar in the LEBT for beam space charge compensation. In addition, the outgassing of materials exposed to vacuum can play an important role in contamination control and global gas balance. To evaluate the time dependent partial pressure profiles in the H- ion source and the RFQ, electrical network - vacuum analogy and test particle Monte Carlo simulation have been used. The simulation outcome indicates that the pressure requirements are in the reach of the proposed vacuum pumping system. Preliminary results show good agreement between the experimental and the simulated pressure profiles; a calibration campaign is in progress to fully benchmark the implemented calculations. Systematic outgassing rate measurements are on-going for critical components in the ion source and RFQ. Amongst them those for the Cu-coated SmCo magnet located in the vacuum system of the biased electron dump electrode, show results lower to stainless steel at room temperature.

A photocathode rf gun design for a mm-wave linac-based FEL

Energy Technology Data Exchange (ETDEWEB)

Nassiri, A.; Berenc, T,; Foster, J.; Waldschmidt, G.; Zhou, J.

1995-07-01

In recent years, advances in the rf gun technology have made it possible to produce small beam emittances suitable for short period microundulators which take advantage of the low emittance beam to reduce the wavelength of FELs. At the Advanced Photon Source, we are studying the design of a compact 50-MeV superconducting mm-wave linac-based FEL for the production of short wavelengths ({approximately}300 nm) to carry out FEL demonstration experiments. The electron source considered for the linac is a 30- GHz, 3 1/2-cell {pi}-mode photocathode rf gun. For cold model rf measurements a 15-GHz prototype structure was fabricated. Here we report on the design, numerical modelling and the initial cold-model rf measurement results on the 15-GHz prototype structure.

A photocathode rf gun design for a mm-wave linac-based FEL

International Nuclear Information System (INIS)

Nassiri, A.; Berenc, T.; Foster, J.; Waldschmidt, G.; Zhou, J.

1995-01-01

In recent years, advances in the rf gun technology have made it possible to produce small beam emittances suitable for short period microundulators which take advantage of the low emittance beam to reduce the wavelength of FELs. At the Advanced Photon Source, we are studying the design of a compact 50-MeV superconducting mm-wave linac-based FEL for the production of short wavelengths (∼300 nm) to carry out FEL demonstration experiments. The electron source considered for the linac is a 30- GHz, 3 1/2-cell π-mode photocathode rf gun. For cold model rf measurements a 15-GHz prototype structure was fabricated. Here we report on the design, numerical modelling and the initial cold-model rf measurement results on the 15-GHz prototype structure

Annex to 7-GeV Advanced Photon Source Conceptual Design Report

International Nuclear Information System (INIS)

1988-05-01

The Annex to the 7-GeV Advanced Photon Source Conceptual Design Report updates the Conceptual Design Report of 1987 (CDR-87) to include the results of further optimization and changes of the design during the past year. The design changes can be summarized as affecting three areas: the accelerator system, conventional facilities, and experimental systems. Most of the changes in the accelerator system result from inclusion of a positron accumulator ring (PAR), which was added at the suggestion of the 1987 DOE Review Committee, to speed up the filling rate of the storage ring. The addition of the PAR necessitates many minor changes in the linac system, the injector synchrotron, and the low-energy beam transport lines. 63 figs., 18 tabs

Overview and status of the advanced photon source at Argonne National Laboratory

International Nuclear Information System (INIS)

White, M.

1994-01-01

The Advanced Photon Source (APS) is a state-of-the-art synchrotron light source facility dedicated to the production of extremely brilliant X-ray beams for research. Its super-intense X-ray beams will be used for many areas of research including industrial research, biological and medical research, defense-related research, and basic research. The APS X-ray beams will allow scientists to study smaller samples, more complex systems, faster reactions and processes, and gather data at a greater level of detail than has been possible to date. Creation of these beams begins with electron production by an electron with a thermionic cathode. The electrons are accelerated to 200 MeV by a linear accelerator (linac) and then impinge on a tungsten target. resulting in electron-positron pair production. The positrons are accelerated to 450 MeV in the remainder of the linac, then accumulated, damped, and transferred to a synchrotron which increases their energy to 7-GeV. The 7-GeV positrons are injected into a storage ring, where they pass through special magnets and emit X-rays of the desired quality. The APS is under construction at ANL at this time, and will begin operating for users in 1996. The accelerator and experimental facilities are described in this paper, and an overview of some of the experimental programs is given

Ion Sources and Injectors for HIF Induction Linacs

International Nuclear Information System (INIS)

Kwan, J.W.; Ahle, L.; Beck, D.N.; Bieniosek, F. M.; Faltens, A.; Grote, D.P.; Halaxa, E.; Henestroza, E.; Herrmannsfeldt, W.B.; Karpenko, V.; Sangster, T.C.

2000-01-01

Ion source and injector development is one of the major parts of the HIF program in the USA. Our challenge is to design a cost effective driver-scale injector and to build a multiple beam module within the next couple of years. In this paper, several current-voltage scaling laws are summarized for guiding the injector design. Following the traditional way of building injectors for HIF induction linac, we have produced a preliminary design for a multiple beam driver-scale injector. We also developed an alternate option for a high current density injector that is much smaller in size. One of the changes following this new option is the possibility of using other kinds of ion sources than the surface ionization sources. So far, we are still looking for an ideal ion source candidate that can readily meet all the essential requirements

First MR images obtained during megavoltage photon irradiation from a prototype integrated linac-MR system

International Nuclear Information System (INIS)

Fallone, B. G.; Murray, B.; Rathee, S.; Stanescu, T.; Steciw, S.; Vidakovic, S.; Blosser, E.; Tymofichuk, D.

2009-01-01

The authors report the first magnetic resonance (MR) images produced by their prototype MR system integrated with a radiation therapy source. The prototype consists of a 6 MV linac mounted onto the open end of a biplanar 0.2 T permanent MR system which has 27.9 cm pole-to-pole opening with flat gradients (40 mT/m) running under a TMX NRC console. The distance from the magnet isocenter to the linac target is 80 cm. The authors' design has resolved the mutual interferences between the two devices such that the MR magnetic field does not interfere with the trajectory of the electron in the linac waveguide, and the radiofrequency (RF) signals from each system do not interfere with the operation of the other system. Magnetic and RF shielding calculations were performed and confirmed with appropriate measurements. The prototype is currently on a fixed gantry; however, in the very near future, the linac and MR magnet will rotate in unison such that the linac is always aimed through the opening in the biplanar magnet. MR imaging was found to be fully operational during linac irradiation and proven by imaging a phantom with conventional gradient echo sequences. Except for small changes in SNR, MR images produced during irradiation were visually and quantitatively very similar to those taken with the linac turned off. This prototype system provides proof of concept that the design has decreased the mutual interferences sufficiently to allow the development of real-time MR-guided radiotherapy. Low field-strength systems (0.2-0.5 T) have been used clinically as diagnostic tools. The task of the linac-MR system is, however, to provide MR guidance to the radiotherapy beam. Therefore, the 0.2 T field strength would provide adequate image quality for this purpose and, with the addition of fast imaging techniques, has the potential to provide 4D soft-tissue visualization not presently available in image-guided radiotherapy systems. The authors' initial design incorporates a

Autopilot regulation for the Linac4 H- ion source

Science.gov (United States)

Voulgarakis, G.; Lettry, J.; Mattei, S.; Lefort, B.; Costa, V. J. Correia

2017-08-01

Linac4 is a 160 MeV H- linear accelerator part of the upgrade of the LHC injector chain. Its cesiated surface H- source is designed to provide a beam intensity of 40-50mA. It is operated with periodical Cs-injection at typically 30 days intervals [1] and this implies that the beam parameters will slowly evolve during operation. Autopilot is a control software package extending CERN developed Inspector framework. The aim of Autopilot is to automatize the mandatory optimization and cesiation processes and to derive performance indicators, thus keeping human intervention minimal. Autopilot has been developed by capitalizing on the experience from manually operating the source. It comprises various algorithms running in real-time, which have been devised to: • Optimize the ion source performance by regulation of H2 injection, RF power and frequency. • Describe the performance of the source with performance indicators, which can be easily understood by operators. • Identify failures, try to recover the nominal operation and send warning in case of deviation from nominal operation. • Make the performance indicators remotely available through Web pages.Autopilot is at the same level of hierarchy as an operator, in the CERN infrastructure. This allows the combination of all ion source devices, providing the required flexibility. Autopilot is executed in a dedicated server, ensuring unique and centralized control, yet allowing multiple operators to interact at runtime, always coordinating between them. Autopilot aims at flexibility, adaptability, portability and scalability, and can be extended to other components of CERN's accelerators. In this paper, a detailed description of the Autopilot algorithms is presented, along with first results of operating the Linac4 H- Ion Source with Autopilot.

Linac4 H{sup −} ion sources

Energy Technology Data Exchange (ETDEWEB)

Lettry, J., E-mail: Jacques.lettry@cern.ch; Aguglia, D.; Andersson, P.; Bertolo, S.; Butterworth, A.; Coutron, Y.; Dallocchio, A.; David, N.; Chaudet, E.; Fink, D. A.; Garlasche, M.; Grudiev, A.; Guida, R.; Hansen, J.; Haase, M.; Jones, A.; Koszar, I.; Lallement, J.-B.; Lombardi, A. M.; Machado, C. [CERN-ABP, 1211 Geneva 23 (Switzerland); and others

2016-02-15

CERN’s 160 MeV H{sup −} linear accelerator (Linac4) is a key constituent of the injector chain upgrade of the Large Hadron Collider that is being installed and commissioned. A cesiated surface ion source prototype is being tested and has delivered a beam intensity of 45 mA within an emittance of 0.3 π ⋅ mm ⋅ mrad. The optimum ratio of the co-extracted electron- to ion-current is below 1 and the best production efficiency, defined as the ratio of the beam current to the 2 MHz RF-power transmitted to the plasma, reached 1.1 mA/kW. The H{sup −} source prototype and the first tests of the new ion source optics, electron-dump, and front end developed to minimize the beam emittance are presented. A temperature regulated magnetron H{sup −} source developed by the Brookhaven National Laboratory was built at CERN. The first tests of the magnetron operated at 0.8 Hz repetition rate are described.

An Optimized Low-Charge Configuration of the LINAC Coherent Light Source

CERN Document Server

Emma, Paul; Huang, Zhirong; Limborg-Deprey, Cecile; Reiche, Sven; Wu, Juhao; Zolotorev, Max S

2005-01-01

The Linac Coherent Light Source (LCLS) is an x-ray free-electron laser (FEL) project based on the SLAC linac. The nominal parameter set is founded on a 1-nC bunch charge and normalized emittance of about 1 micron. The most challenging issues, such as emittance generation, wakefields, and coherent synchrotron radiation (CSR), are associated with the high bunch charge. In the LCLS in particular, with its strong linac wakefields, the bunch compression process produces sharp temporal horns at the head and tail of the bunch with degraded local emittance, effectively wasting much of the charge. The sharp horns intensify CSR in the bends and further drive a strong resistive-wall wakefield in the long FEL undulator. Although these issues are not insurmountable, they suggest a lower bunch charge may be more suitable. This study uses a 0.2-nC bunch charge and 0.85-micron emittance with only 30 A of peak current in the injector, producing the same FEL saturation length. The resulting performance is more stable, has negl...

On scaling and optimization of high-intensity, low-beam-loss RF linacs for neutron source drivers

International Nuclear Information System (INIS)

Jameson, R.A.

1992-01-01

RF linacs providing cw proton beams of 30--250 mA at 800--1600 MeV, and cw deuteron beams of 100--250 mA at 35--40 MeV, are needed as drivers for factory neutron sources applied to radioactive waste transmutation, advanced energy production, materials testing facilities, and spallation neutron sources. The maintenance goals require very low beam loss along the linac. Optimization of such systems is complex; status of beam dynamics aspects presently being investigated is outlined

A Compact 5 MeV S-Band Electron Linac Based X-Ray Source for Industrial Radiography

CERN Document Server

Auditore, Lucrezia; De Pasquale, Domenico; Emanuele, Umberto; Italiano, Antonio; Trifirò, Antonio; Trimarchi, Marina

2005-01-01

A compact and reliable X-ray source, based on a 5 MeV, 1 kW, S-band electron linac, has been set up at the Dipartimento di Fisica, Universit\\'a di Messina. This source, coupled with a GOS scintillator screen and a CCD camera, represents an innovative transportable system for industrial radiography and X-ray tomography. Optimization of the parameters influencing the e-gamma conversion and the X-ray beam characteristics have been studied by means of the MCNP-4C2 code. The converter choice is the result of the study of the e-gamma conversion performances for different materials and materials thicknesses. Also the converter position with respect to the linac exit window was studied. The chosen converter consists in a Ta-Cu target inserted close to the linac window. The Cu layer acts as a filter both on the electrons from the source and on the low energy X-rays. The X-ray beam angular profile was studied by means of GafChromic films with and without collimation. In the final source project, a collimation system pr...

Positron annihilation spectroscopy using high-energy photons

International Nuclear Information System (INIS)

Butterling, Maik; Jungmann, Marco; Krause-Rehberg, Reinhard; Krille, Arnold; Anwand, Wolfgang; Brauer, Gerhard; Cowan, Thomas E.; Hartmann, Andreas; Kosev, Krasimir; Schwengner, Ronald; Wagner, Andreas

2010-01-01

The superconducting electron accelerator ELBE (Electron Linac with high Brilliance and low Emittance) at the Research Centre Dresden-Rossendorf (Germany) serves as a high-intensity bremsstrahlung photon-source delivering a pulsed beam (26 MHz) with very short bunches (<5 ps). The photons are being converted into positrons by means of pair production inside the target material thus forming an intense positron source. The accelerator machine pulse is used as time reference allowing positron lifetime spectroscopy. We performed positron annihilation spectroscopy by pair production in different sample materials and used coincidence techniques to reduce the background due to scattered photons significantly in order resulting in spectra of extraordinary high quality. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

Photon sources for absorptiometric measurements

International Nuclear Information System (INIS)

Witt, R.M.; Sandrik, J.M.; Cameron, J.R.

1976-01-01

Photon absorptiometry is defined and the requirements of photon sources for these measurements are described. Both x-ray tubes and radionuclide sources are discussed, including the advantages of each in absorptiometric systems

Fault-tolerant superconducting linac design for a 5-MW neutron spallation source

International Nuclear Information System (INIS)

Swain, G.R.

1993-01-01

An 805-MHz superconducting linac is proposed which could accelerate protons from 0.1 to 2.0 GeV in less than 730 m for a peak surface field in the cavities of 17 MV/m. The linac would furnish 5 MW of beam for a neutron spallation source, plus up to 10 additional MW of beam for other purposes. The design uses 454 elliptical cavities arranged in twelve groups, identical cavities being used within each group. Characterization of elliptical cavities for betas from 0.44 to 0.94 and the steps of the design procedure are presented. The effective peak power fed by each rf coupler would be less than 100 kW for all of the cavities. 6.5 kW of power at 2 deg K would need to be extracted by the cryogenic system. Space charge was found to have a negligible effect on emittance growth. The design is such that one cavity per group could be inoperable, and the gradient in the remaining cavities could be increased to compensate. The longitudinal and transverse acceptances of the linac would not be significantly degraded under such fault conditions. A corresponding 402.5 MHz linac design is being developed

Optimization of the beam extraction systems for the Linac4 H{sup −} ion source

Energy Technology Data Exchange (ETDEWEB)

Fink, D. A.; Lettry, J.; Scrivens, R.; Steyaert, D. [CERN, 1211 Geneva 23 (Switzerland); Midttun, Ø. [University of Oslo, P.O. Box 1048, 0316 Oslo (Norway); CERN, 1211 Geneva 23 (Switzerland); Valerio-Lizarraga, C. A. [Departamento de Investigación en Fisica, Universidad de Sonora, Hermosillo (Mexico); CERN, 1211 Geneva 23 (Switzerland)

2015-04-08

The development of the Linac 4 and its integration into CERN’s acceleration complex is part of the foreseen luminosity upgrade of the Large Hadron Collider (LHC). The goal is to inject a 160 MeV H{sup −} beam into the CERN PS Booster (PSB) in order to increase the beam brightness by a factor of 2 compared to the 50 MeV proton linac, Linac 2, that is currently in operation. The requirements for the ion source are a 45 keV H{sup −} beam of 80 mA intensity, 2 Hz repetition rate and 0.5 ms pulse length within a normalized rms-emittance of 0.25 mm· mrad. The previously installed beam extraction system has been designed for an H{sup −} ion beam intensity of 20 mA produced by an RF-volume source with an electron to H{sup −} ratio of up to 50. For the required intensity upgrades of the Linac4 ion source, a new beam extraction system is being produced and tested; it is optimized for a cesiated surface RF-source with a nominal beam current of 40 mA and an electron to H{sup −} ratio of 4. The simulations, based on the IBSIMU code, are presented. At the Brookhaven National Laboratory (BNL), a peak beam current of more than 100 mA was demonstrated with a magnetron H{sup −} source at an energy of 35 keV and a repetition rate of 2 Hz. A new extraction system is required to operate at an energy of 45 keV; simulation of a two stage extraction system dedicated to the magnetron is presented.

Tailoring single-photon and multiphoton probabilities of a single-photon on-demand source

International Nuclear Information System (INIS)

Migdall, A.L.; Branning, D.; Castelletto, S.

2002-01-01

As typically implemented, single-photon sources cannot be made to produce single photons with high probability, while simultaneously suppressing the probability of yielding two or more photons. Because of this, single-photon sources cannot really produce single photons on demand. We describe a multiplexed system that allows the probabilities of producing one and more photons to be adjusted independently, enabling a much better approximation of a source of single photons on demand

Alternate Tunings for the Linac Coherent Light Source Photoinjector

CERN Document Server

Limborg-Deprey, Cecile

2005-01-01

The Linac Coherent Light Source (LCLS) is an x-ray free-electron laser (FEL) project based on the SLAC linac. The LCLS Photoinjector beamline has been designed to deliver 10 ps long electron bunches of 1nC with a normalized transverse emittance of less than 1 mm.mrad for 80% of the slices constituting the core of the bunch at 135 MeV. Tolerances and regulation requirements are tight for this tuning. The main contribution to emittance is the "cathode emittance which counts for 0.72 mm.mrad for the nominal tuning. As the "cathode emittance" scales linearly with laser spot radius, the emittance will be dramatically reduced for smaller radius, but this is only possible at lower charge. In particular, for a 0.2nC, we believe we can achieve an emittance closer to 0.4 mm.mrad. This working point will be easier to tune and the beam quality should be much easier to maintain than for the nominal one. In this paper, we also discuss how emittance could be further reduced by using the appropriate laser pulse shaping.

Photon Factory activity report, 1991

International Nuclear Information System (INIS)

1992-01-01

The Photon Factory is a national synchrotron radiation research facility affiliated with the National Laboratory for High Energy Physics located in Tsukuba Science City. The Photon Factory consists of a 2.5 GeV electron/positron linear accelerator, a 2.5 GeV electron/positron storage ring, beam lines and experimental stations. All the facilities for synchrotron radiation research are open to scientists. A part of the accumulation ring of the TRISTAN main ring has been used as a synchrotron radiation source in the energy range from 5.8 to 6.5 GeV. The Photon Factory is composed of three divisions of Injector Linac, Light Source and Instrumentation. The researches of each divisions are reviewed, and the users' short reports are collected. The list of published papers with author index is also included in the publication. (K.I.) 233 refs

Characterization techniques for the high-brightness particle beams of the Advanced Photon Source (APS)

International Nuclear Information System (INIS)

Lumpkin, A.H.

1993-01-01

The Advanced Photon Source (APS) will be a third-generation synchrotron radiation (SR) user facility in the hard x-ray regime (10--100 keV). The design objectives for the 7-GeV storage ring include a positron beam natural emittance of 8 x 10 -9 m-rad at an average current of 100 mA. Proposed methods for measuring the transverse and longitudinal profiles will be described. Additionally, a research and development effort using an rf gun as a low-emittance source of electrons for injection into the 200- to 650-MeV linac subsystem is underway. This latter system is projected to produce electron beams with a normalized, rms emittance of ∼2 π mm-mrad at peak currents of near one hundred amps. This interesting characterization problem will also be briefly discussed. The combination of both source types within one laboratory facility will stimulate the development of diagnostic techniques in these parameter spaces

Cumulative beam break-up study of the spallation neutron source superconducting linac

CERN Document Server

Jeon, D; Krafft, G A; Yunn, B; Sundelin, R; Delayen, J; Kim, S; Doleans, M

2002-01-01

Beam instabilities due to High Order Modes (HOMs) are a concern to superconducting (SC) linacs such as the Spallation Neutron Source (SNS) linac. The effects of pulsed mode operation on transverse and longitudinal beam breakup instability are studied for H sup - beam in a consistent manner for the first time. Numerical simulation indicates that cumulative transverse beam breakup instabilities are not a concern in the SNS SC linac, primarily due to the heavy mass of H sup - beam and the HOM frequency spread resulting from manufacturing tolerances. As little as +-0.1 MHz HOM frequency spread stabilizes all the instabilities from both transverse HOMs, and also acts to stabilize the longitudinal HOMs. Such an assumed frequency spread of +-0.1 MHz HOM is small, and hence conservative compared with measured values of sigma=0.00109(f sub H sub O sub M -f sub 0)/f sub 0 obtained from Cornell and the Jefferson Lab Free Electron Laser cavities. However, a few cavities may hit resonance lines and generate a high heat lo...

Optimized sub thermal neutron source to Linac of CAB

International Nuclear Information System (INIS)

Torres, L; Granada, R

2006-01-01

We present the results of calculations performed with the code M C N P relative to the neutron field behavior within the moderator for the Bariloche-Linac cold neutron source, using polyethylene as pre moderator and solid mesitylene as moderating material at 90 K.The optimum dimensions for a moderator were obtained, with and without a pre moderator, from the point of view of neutron production and time-width of the neutron pulse.Finally, we adopted for our cold neutron source, a slab pre moderator of P L E at room temperature, and a cylindrical moderator of mesitylene at 90 K with a cooler system of stainless steel with windows of Zircaloy-4 [es

Photon statistics characterization of a single-photon source

International Nuclear Information System (INIS)

Alleaume, R; Treussart, F; Courty, J-M; Roch, J-F

2004-01-01

In a recent experiment, we reported the time-domain intensity noise measurement of a single-photon source relying on single-molecule fluorescence control. In this paper, we present data processing starting from photocount timestamps. The theoretical analytical expression of the time-dependent Mandel parameter Q(T) of an intermittent single-photon source is derived from ON↔OFF dynamics. Finally, source intensity noise analysis, using the Mandel parameter, is quantitatively compared with the usual approach relying on the time autocorrelation function, both methods yielding the same molecular dynamical parameters

Linac Coherent Light Source (LCLS) design study report

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-04-01

The Stanford Linear Accelerator Center (SLAC), in collaboration with Los Alamos National Laboratory, Lawrence Livermore National Laboratory, and the University of California at Los Angeles, is proposing to build a Free-Electron-Laser (FEL) R and D facility operating in the self-amplified spontaneous emission (SASE) mode in the wavelength range 1.5--15 {angstrom}. This FEL, called Linac Coherent Light Source (LCLS), utilizes the SLAC linac and produces sub-picosecond pulses of short wavelength x-rays with very high peak brightness and full transverse coherence. In this report, the Design Team has established performance parameters for all the major components of the LCLS and developed a layout of the entire system. Chapter 1 is the Executive Summary. Chapter 2 (Overview) provides a brief description of each of the major sections of the LCLS, from the rf photocathode gun, through the experimental stations and electron beam dump. Chapter 3 describes the scientific case for the LCLS. Chapter 4 provides a review of the principles of the FEL physics that the LCLS is based on, and Chapter 5 discusses the choice of the system's physical parameters. Chapters 6 through 10 describe in detail each major element of the system. Chapters 11 through 13 respectively cover undulator controls, mechanical alignment, and radiation issues.

Linac Coherent Light Source (LCLS) design study report

International Nuclear Information System (INIS)

1998-04-01

The Stanford Linear Accelerator Center (SLAC), in collaboration with Los Alamos National Laboratory, Lawrence Livermore National Laboratory, and the University of California at Los Angeles, is proposing to build a Free-Electron-Laser (FEL) R and D facility operating in the self-amplified spontaneous emission (SASE) mode in the wavelength range 1.5--15 angstrom. This FEL, called Linac Coherent Light Source (LCLS), utilizes the SLAC linac and produces sub-picosecond pulses of short wavelength x-rays with very high peak brightness and full transverse coherence. In this report, the Design Team has established performance parameters for all the major components of the LCLS and developed a layout of the entire system. Chapter 1 is the Executive Summary. Chapter 2 (Overview) provides a brief description of each of the major sections of the LCLS, from the rf photocathode gun, through the experimental stations and electron beam dump. Chapter 3 describes the scientific case for the LCLS. Chapter 4 provides a review of the principles of the FEL physics that the LCLS is based on, and Chapter 5 discusses the choice of the system's physical parameters. Chapters 6 through 10 describe in detail each major element of the system. Chapters 11 through 13 respectively cover undulator controls, mechanical alignment, and radiation issues

High brightness single photon sources based on photonic wires

DEFF Research Database (Denmark)

Claudon, J.; Bleuse, J.; Bazin, M.

2009-01-01

We present a novel single-photon-source based on the emission of a semiconductor quantum dot embedded in a single-mode photonic wire. This geometry ensures a very large coupling (> 95%) of the spontaneous emission to the guided mode. Numerical simulations show that a photon collection efficiency...

Linac Coherent Light Source Undulator RF BPM System

International Nuclear Information System (INIS)

Lill, R.M.; Morrison, L.H.; Waldschmidt, G.J.; Walters, D.R.; Argonne; Johnson, R.; Li, Z.; Smith, S.; Straumann, T.; SLAC

2007-01-01

The Linac Coherent Light Source (LCLS) will be the world's first x-ray free-electron laser (FEL) when it becomes operational in 2009. The LCLS is currently in the construction phase. The beam position monitor (BPM) system planned for the LCLS undulator will incorporate a high-resolution X-band cavity BPM system described in this paper. The BPM system will provide high-resolution measurements of the electron beam trajectory on a pulse-to-pulse basis and over many shots. The X-band cavity BPM size, simple fabrication, and high resolution make it an ideal choice for LCLS beam position detection. We will discuss the system specifications, design, and prototype test results

Thermal Analysis of the Linac3 GTS-LHC ECR Ion Source

CERN Document Server

Fichera, Claudio; Toivanen, Ville Aleksi; Kuchler, Detlef; CERN. Geneva. ATS Department

2017-01-01

The Linac3 ion source produces lead beams by the vaporization of solid samples inside internal ovens. The geometry, materials and surface state of the oven elements are critical parameters influencing the temperature distribution in the environment, and thus the performance of the source. A finite element approach is proposed to evaluate the thermal response of the system at increasing heating powers. Comparisons between the simulations results and experimental measurements are given in order to validate the numerical model. Based on the obtained results, improvements to the existing setup are suggested.

Highly efficient sources of single indistinguishable photons

DEFF Research Database (Denmark)

Gregersen, Niels

2013-01-01

be electrically driven. Several design strategies addressing these requirements have been proposed. In the cavity-based source, light emission is controlled using resonant cavity quantum electrodynamics effects, whereas in the waveguide-based source, broadband electric field screening effects are employed......Solid-state sources capable of emitting single photons on demand are of great interest in quantum information applications. Ideally, such a source should emit exactly one photon into the collection optics per trigger, the emitted photons should be indistinguishable and the source should...

The Advanced Photon Source injection timing system

International Nuclear Information System (INIS)

Lenkszus, F.R.; Laird, R.

1995-01-01

The Advanced Photon Source consists of five accelerators. The injection timing system provides the signals required to cause a bunch emitted from the electron gun to navigate through intermediate accelerators to a specific bucket (1 out of 1296) within the storage ring. Two linacs and a positron accumulator ring operate at 60Hz while a booster synchrotron ramps and injects into the storage ring at 2Hz. The distributed, modular VME/VXI-based injection timing system is controlled by two EPICS-based input/output controllers (IOCs). Over 40 VME/VXI cards have been developed to implement the system. Card types range from 352MHz VXI timing modules to VME-based fiber optic fanouts and logic translators/drivers. All timing is distributed with fiber optics. Timing references are derived directly from machine low-level rf of 9.77MHz and 352MHz. The timing references provide triggers to programmable delay generators. Three grades of timing are provided. Precision timing is derived from commercial digital delay generators, intermediate precision timing is obtained from VXI 8-channel digital delay generators which provide timing with 25ns peak-to-peak jitter, and modest precision timing is provided by the APS event system. The timing system is fully integrated into the APS EPICS-based control system

Light ion linacs for medical applications

International Nuclear Information System (INIS)

Bradbury, J.N.; Knapp, E.A.; Nagle, D.E.

1975-01-01

Recent advances in linear accelerator technology point to the feasibility of designing and developing practical medical linacs for producing protons, neutrons, or π mesons for the radiation therapy of cancer. Additional uses of such linacs could include radioisotope production and charged particle radiography. For widespread utilization medical linacs must exhibit reasonable cost, compactness, reliability, and simplicity of operation. Possible extensions of current accelerator technology which might provide these characteristics are discussed in connection with linac design, fabrication techniques, materials, power sources, injectors, and particle collection and delivery systems. Parameters for a medical proton linac for producing pions are listed. (U.S.)

Testing and Implementation Progress on the Advanced Photon Source (APS) Linear Accelerator (Linac) High-Power S-band Switching System

OpenAIRE

Grelick, A. E.; Arnold, N.; Berg, S.; Dohan, D.; Goeppner, G.; Kang, Y. W.; Nassiri, A.; Pasky, S.; Pile, G.; Smith, T.; Stein, S. J.

2000-01-01

An S-band linear accelerator is the source of particles and the front end of the Advanced Photon Source injector. In addition, it supports a low-energy undulator test line (LEUTL) and drives a free-electron laser (FEL). A waveguide-switching and distribution system is now under construction. The system configuration was revised to be consistent with the recent change to electron-only operation. There are now six modulator-klystron subsystems, two of which are being configured to act as hot sp...

Inverse Compton scattering X-ray source yield optimization with a laser path folding system inserted in a pre-existent RF linac

Energy Technology Data Exchange (ETDEWEB)

Chaleil, A.; Le Flanchec, V.; Binet, A.; Nègre, J.P.; Devaux, J.F.; Jacob, V.; Millerioux, M.; Bayle, A.; Balleyguier, P. [CEA DAM DIF, F-91297 Arpajon (France); Prazeres, R. [CLIO/LCP, Bâtiment 201, Université Paris-Sud, F-91450 Orsay (France)

2016-12-21

An inverse Compton scattering source is under development at the ELSA linac of CEA, Bruyères-le-Châtel. Ultra-short X-ray pulses are produced by inverse Compton scattering of 30 ps-laser pulses by relativistic electron bunches. The source will be able to operate in single shot mode as well as in recurrent mode with 72.2 MHz pulse trains. Within this framework, an optical multipass system that multiplies the number of emitted X-ray photons in both regimes has been designed in 2014, then implemented and tested on ELSA facility in the course of 2015. The device is described from both geometrical and timing viewpoints. It is based on the idea of folding the laser optical path to pile-up laser pulses at the interaction point, thus increasing the interaction probability. The X-ray output gain measurements obtained using this system are presented and compared with calculated expectations.

Linac4: injecting new life into the LHC

CERN Multimedia

Antonella Del Rosso

2015-01-01

Construction work is nearing completion on the ion source for Linac4, the new linear accelerator that forms part of the LHC injector upgrade programme. Here we find out more about this essential component of the accelerator chain, designed and built at CERN.     The image shows the Linac4 H- source. The red light is the alpha line of the visible hydrogen emission spectrum. The ion source is a key component of Linac4, the linear accelerator that from 2018 will supply H- ions (hydrogen atoms with an extra electron) at 160 MeV for injection into the accelerator complex. As the only ion source at CERN, Linac4 must be highly reliable, which requires a full understanding of the production mechanisms, the simulation of physical processes and the validation of those processes through experimentation. “This source is the result of much fruitful collaboration,” says Jacques Lettry of the BE department. “Its design was inspired by the many sources of th...

SU-E-T-119: Dosimetric and Mechanical Characteristics of Elekta Infinity LINAC with Agility MLC

International Nuclear Information System (INIS)

Park, J; Xu, Q; Xue, J; Zhai, Y; An, L; Chen, Y

2014-01-01

Purpose: Elekta Infinity is the one of the latest generation LINAC with unique features. Two Infinity LINACs are recently commissioned at our institution. The dosimetric and mechanical characteristics of the machines are presented. Methods: Both Infinity LINACs with Agility MLC (160 leaves with 0.5 cm leaf width) are configured with five electron energies (6, 9, 12, 15, and 18 MeV) and two photon energies (6 and 15 MV). One machine has additional photon energy (10 MV). The commissioning was performed by following the manufacturer's specifications and AAPM TG recommendations. Beam data of both electron and photon beams are measured with scanning ion chambers and linear diode array. Machines are adjusted to have the dosimetrically equivalent characteristics. Results: The commissioning of mechanical and imaging system meets the tolerances by TG recommendations. The PDD 10 of various field sizes for 6 and 15 MV shows < 0.5% difference between two machines. For each electron beams, R 80 matches with < 0.4 mm difference. The symmetry and flatness agree within 0.8% and 0.9% differences for photon beams, respectively. For electron beams, the differences of the symmetry and flatness are within 1.2% and 0.8%, respectively. The mean inline penumbras for 6, 10, and 15 MV are respectively 5.1±0.24, 5.6±0.07, and 5.9±0.10 mm for 10x10 cm at 10 cm depth. The crossline penumbras are larger than inline penumbras by 2.2, 1.4, and 1.0 mm, respectively. The MLC transmission factor with interleaf leakage is 0.5 % for all photon energies. Conclusion: The dosimetric and mechanical characteristics of two Infinity LINACs show good agreements between them. Although the Elekta Infinity has been used in many institutions, the detailed characteristics of the machine have not been reported. This study provides invaluable information to understand the Infinity LINAC and to compare the quality of commissioning data for other LINACs

Design and simulation of an optimized e-linac based neutron source for BNCT research

International Nuclear Information System (INIS)

Durisi, E.; Alikaniotis, K.; Borla, O.; Bragato, F.; Costa, M.; Giannini, G.; Monti, V.; Visca, L.; Vivaldo, G.; Zanini, A.

2015-01-01

The paper is focused on the study of a novel photo-neutron source for BNCT preclinical research based on medical electron Linacs. Previous studies by the authors already demonstrated the possibility to obtain a mixed thermal and epithermal neutron flux of the order of 10"7 cm"−"2 s"−"1. This paper investigates possible Linac’s modifications and a new photo-converter design to rise the neutron flux above 5 10"7 cm"−"2 s"−"1, also reducing the gamma contamination. - Highlights: • Proposal of a mixed thermal and epithermal (named hyperthermal) neutron source based on medical high energy electron Linac. • Photo-neutron production via Giant Dipole Resonance on high Z materials. • MCNP4B-GN simulations to design the photo-converter geometry maximizing the hyperthermal neutron flux and minimizing the fast neutron and gamma contaminations. Hyperthermal neutron field suitable for BNCT preclinical research.

The Development of the Linac Coherent Light Source RF Gun

International Nuclear Information System (INIS)

Dowell, D

2008-01-01

The Linac Coherent Light Source (LCLS) is the first x-ray laser user facility based upon a free electron laser (FEL) requiring extraordinary beam quality to saturate at 1.5 angstroms within a 100 meter undulator.[1] This new type of light source is using the last kilometer of the three kilometer linac at SLAC to accelerate the beam to an energy as high as 13.6 GeV and required a new electron gun and injector to produce a very bright beam for acceleration. At the outset of the project it was recognized that existing RF guns had the potential to produce the desired beam but none had demonstrated it. Therefore a new RF gun or at least the modification of an existing gun was necessary. The parameters listed in Table 1 illustrate the unique characteristics of LCLS which drive the requirements for the electron gun as given in Table 2. The gun beam quality needs to accommodate emittance growth as the beam is travels through approximately one kilometer of linac and two bunch compressors before reaching the undulator. These beam requirements were demonstrated during the recent commissioning runs of the LCLS injector and linac [2] due to the successful design, fabrication, testing and operation of the LCLS gun. The goal of this paper is to relate the technical background of how the gun was able to achieve and in some cases exceed these requirements by understanding and correcting the deficiencies of the prototype s-band RF photocathode gun, the BNL/SLAC/UCLA Gun III. This paper begins with a brief history and technical description of Gun III and the Gun Test Facility (GTF) at SLAC, and studies of the gun's RF and emittance compensation solenoid. The work at the GTF identified the gun and solenoid deficiencies, and helped to define the specifications for the LCLS gun. Section 1.1.5 describes the modeling used to compute and correct the gun RF fields and Section 1.1.6 describes the use of these fields in the electron beam simulations. The magnetic design and measurements of

A bright single-photon source based on a photonic trumpet

DEFF Research Database (Denmark)

Munsch, Mathieu; Malik, Nitin S.; Bleuse, Joël

Fiber-like photonic nanowires, which are optical waveguides made of a high refractive index material n, have recently emerged as non-resonant systems providing an efficient spontaneous emission (SE) control. When they embed a quantum emitter like a quantum dot (QD), they find application to the r......Fiber-like photonic nanowires, which are optical waveguides made of a high refractive index material n, have recently emerged as non-resonant systems providing an efficient spontaneous emission (SE) control. When they embed a quantum emitter like a quantum dot (QD), they find application...... to the realization of bright sources of quantum light and, reversibly, provide an efficient interface between propagating photons and the QD. For a wire diameter ∼ λ/n (λ is the operation wavelength), the fraction of QD SE coupled to the fundamental guided mode exceeds 90%. The collection of the photons can...... be brought close to unity with a proper engineering of the wire ends. In particular, a tapering of the top wire end is necessary to achieve a directive far-field emission pattern [1]. Recently, we have realized a single-photon source featuring a needle-like taper. The source efficiency, though record...

Performance of a beam-multiplexing diamond crystal monochromator at the Linac Coherent Light Source

DEFF Research Database (Denmark)

Zhu, Diling; Feng, Yiping; Stoupin, Stanislav

2014-01-01

A double-crystal diamond monochromator was recently implemented at the Linac Coherent Light Source. It enables splitting pulses generated by the free electron laser in the hard x-ray regime and thus allows the simultaneous operations of two instruments. Both monochromator crystals are High-Pressu...

Linac-augmented light sources : an incremental concept for enhancing the capabilities of existing 3rd-generation storage rings

International Nuclear Information System (INIS)

Lewellen, J. W.

2003-01-01

Planned and proposed 4th-generation x-ray sources, such as energy-recovery linacs (ERLs) and single-pass x-ray free-electron lasers (X-FELs) offer a number of potential advantages, including small source size, higher peak brightness, ultrashort pulses, and potentially temporally and transversely coherent pulses. While offering unique capabilities, such facilities will also offer several important limitations, including limited numbers of user beamlines (for FELs) and a pulse-repetition rate that may be too high for many dynamics experiments (ERLs). In addition, there are many technical challenges associated with both types of facilities. A third type of facility, exemplified by the Short Pulse Photon Source (SPPS) at SLAC [1], would support neither a large number of users simultaneously nor generate coherent pulses, but would generate very intense, short x-ray pulses. Such a facility could serve as the starting point for either an ERL or an X-FEL, or a combined, hybrid machine. For the foreseeable future, however, existing 3rd-generation light source storage rings, such as the Advanced Photon Source, will continue to play important roles in supporting scientific research utilizing high-brightness x-rays. Existing facilities offer the powerful combination of a large number of user beamlines, efficient use of electron beam energy, and established user communities, and a program of incremental investment in, and improvements to, these facilities should continue to pay dividends into the future. This document discusses potential upgrade paths based on the Advanced Photon Source (APS) as a model 3rd-generation facility. If existing 3rd-generation facilities are to remain centers of excellence for light source-based research into the future, they must not only maintain and enhance their support of their existing user base, but also seek to expand their capabilities to support additional classes of users. There are several paths available toward this goal. The APS is

The quasi-monochromatic photon beam used in photoneutron experiments from 20-120 MeV at the 600 MeV Saclay Linac

International Nuclear Information System (INIS)

Veyssiere, A.; Beil, H.; Bergere, R.; Carlos, P.; Fagot, J.; Lepretre, A.; Ahrens, J.

1979-01-01

A beam of 20-130 MeV positrons, with average intensities between 10 nA and 50 nA, is used at the 600 MeV Saclay Linac to create a quasi-monochromatic photon beam with a continuously variable energy. This beam was used to measure photoneutron cross sections and the corresponding photonuclear facility is first described. The computer-controlled methods, implemented to measure the energy spectrum and the emittance of the positron beam are described. The quasi-monochromatic photon lines are produced by the annihilation in flight of monoenergetic positrons in two annihilation radiators with different Z successively. The photon beam emission angle theta is shown to be the most critical parameter in the search for an optimum overall signal to background ratio for a specific photoneutron experiment. The choice of an angle theta approximately 4 0 is explained for absolute measurements of sigma(γ, xn) cross-sections, for which the used average intensities of monochromatic photons were thus purposely reduced to approximately 5 X 10 3 s -1 , with an energy resolution approximately 12%. (Auth.)

Progress in design of the SNS linac

International Nuclear Information System (INIS)

Hardekopf, R.

2001-01-01

The Spallation Neutron Source (SNS) is a six-laboratory collaboration to build an intense pulsed neutron facility at Oak Ridge, TN. The linac design has evolved from the conceptual design presented in 1997 in order to achieve higher initial performance and to incorporate desirable upgrade features. The linac is now designed to produce 2-MW beam power using a combination of radio-frequency quadrupole (RFQ) linac, drift-tube linac (DTL), coupled-cavity linac (CCL), and superconducting-RF (SRF) linac. Designs of each of these elements support he high peak intensity and high quality beam required for injection into the SNS accumulator ring. This paper will trace the evolution of the linac design and the progress made in the R and D program. (author)

A digital controlled negative high voltage power source for LINAC of HLS

International Nuclear Information System (INIS)

Gao Hui; Chen Jun; Hong Jun; Wang Weibing

2005-01-01

This paper introduces the working principle of a 10-80 kV negative high voltage power source for the electronic gun of the 200 MeV LINAC of NSRL, especially how to realize the switch power, voltage/current sampling, feedback control and microcontroller module. The firmware design for the SOC microcontroller of ADuC8xx and the application software design for PC are also presented. (authors)

Gas Injection And Fast Pressure-Rise Measurements For The Linac4 H− Source

CERN Document Server

Mahner, E; Lettry, J; Mattei, S; O'Neil, M; Neupert, H; Pasquino, C; Schmitzer, C

2013-01-01

In the era of the Large Hadron Collider, the CERN injector complex comprising the 34 years old Linac2 with its primary proton source, is presently upgraded with a new linear accelerator for H− (Linac4). The design, construction, and test of volume production and cesiated RF-driven H− ion sources is presently ongoing with the final goal of producing an H− beam with 80 mA beam current, 45 keV beam energy, 500 s pulse length, and a repetition rate of 2 Hz. In order to have quantitative information of the hydrogen gas density at the moment of plasma ignition the dynamic vacuum properties of the plasma generator were studied experimentally. We describe the experimental setup and present fast pressure-rise measurements for different parameters of the gas injection system, such as gas species (H2, He, N2, Ar), piezo valve voltage pulse length (200 - 500 s), and injection pressure (400 - 2800 mbar). The obtained data are compared with a conductance model of the plasma generator.

Linac coherent light source (LCLS) undulator RF BPM system

International Nuclear Information System (INIS)

Lill, R.; Waldschmidt, G.; Morrison, L.; Smith, S.; Straumann, T; Li, Z.; Johnson, R.

2006-01-01

The Linac Coherent Light Source (LCLS) will be the world's first x-ray free-electron laser (FEL) when it becomes operational in 2009. The LCLS is currently in the construction phase. The beam position monitor (BPM) system planned for the LCLS undulator will incorporate a high-resolution X-band cavity BPM system described in this paper. The BPM system will provide high-resolution measurements of the electron beam trajectory on a pulse-to-pulse basis and over many shots. The X-band cavity BPM size, simple fabrication, and high resolution make it an ideal choice for LCLS beam position detection. We will discuss the system specifications, design, and prototype test results.

Assessment of Impact of Monoenergetic Photon Sources on Prioritized Nonproliferation Applications: Simulation Study Report

Energy Technology Data Exchange (ETDEWEB)

Geddes, Cameron [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ludewigt, Bernhard [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Valentine, John [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Quiter, Brian [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Descalle, Marie-Anne [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Warren, Glen [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kinlaw, Matt [Idaho National Lab. (INL), Idaho Falls, ID (United States); Thompson, Scott [Idaho National Lab. (INL), Idaho Falls, ID (United States); Chichester, David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Miller, Cameron [Univ. of Michigan, Ann Arbor, MI (United States); Pozzi, Sara [Univ. of Michigan, Ann Arbor, MI (United States)

2016-12-30

Near-monoenergetic photon sources (MPSs) have the potential to improve sensitivity at greatly reduced dose in existing applications and enable new capabilities in other applications. MPS advantages include the ability to select energy, energy spread, flux, and pulse structures to deliver only the photons needed for the application, while suppressing extraneous dose and background. Some MPSs also offer narrow divergence photon beams which can target dose and/or mitigate scattering contributions to image contrast degradation. Current broad-band, bremsstrahlung photon sources (e.g., linacs and betatrons) deliver unnecessary dose that in some cases also interferes with the signature to be detected and/or restricts operations, and must be collimated (reducing flux) to generate narrow divergence beams. While MPSs can in principle resolve these issues, they are technically challenging to produce. Candidate MPS technologies for nonproliferation applications are now being developed, each of which have different properties (e.g. broad divergence vs. narrow). Within each technology, source parameters trade off against one another (e.g. flux vs. energy spread), representing a large operation space. To guide development, requirements for each application of interest must be defined and simulations conducted to define MPS parameters that deliver benefit relative to current systems. The present project conducted a broad assessment of potential nonproliferation applications where MPSs may provide new capabilities or significant performance enhancement (reported separately), which led to prioritization of several applications for detailed analysis. The applications prioritized were: cargo screening and interdiction of Special Nuclear Materials (SNM), detection of hidden SNM, treaty/dismantlement verification, and spent fuel dry storage cask content verification. High resolution imaging for stockpile stewardship was considered as a sub-area of the treaty topic, as it is also of

Variable Gap Undulator for 1.5-48 Kev Free Electron Laser at Linac Coherent Light Source

International Nuclear Information System (INIS)

2011-01-01

We study the feasibility of generating femtosecond duration Free-Electron Laser with a variable photon energy from 1.5 to 48 keV, using an electron bunch with the same characteristics of the LINAC Coherent Light Source (LCLS) bunch, and a planar undulator with additional focusing. We assume that the electron bunch energy can be changed, and the undulator has a variable gap, allowing a variable undulator parameter. It is assumed to be operated in an ultra-low charge and ultra-short pulse regime. We study the feasibility of a tunable, short pulse, X-ray FEL with photon energy from 1.5 to 48 keV, using an electron beam like the one in the LCLS and a 2:5 cm period, variable gap, planar undulator. The beam energy changes from 4.6 to 13.8 GeV, the electorn charge is kept at 10 pC, and the undulator parameter varies from 1 to 3. The undulator length needed to saturate the 48 keV FEL is about 55 m, with a peak power around 5 GW. At longer wavelength the saturation length is as short as 15 m, and the peak power around 20 GW. The results from the analytical models and the GENESIS simulations show that the system is feasible. The large wavelength range, full tunability and short, few femtosecond pulses, together with the large peak power, would provide a powerful research tool.

Photon energy tunability of advanced photon source undulators

International Nuclear Information System (INIS)

Viccaro, P.J.; Shenoy, G.K.

1987-08-01

At a fixed storage ring energy, the energy of the harmonics of an undulator can be shifted or ''tuned'' by changing the magnet gap of the device. The possible photon energy interval spanned in this way depends on the undulator period, minimum closed gap, minimum acceptable photon intensity and storage ring energy. The minimum magnet gap depends directly on the stay clear particle beam aperture required for storage ring operation. The tunability of undulators planned for the Advanced Photon Source with first harmonic photon energies in the range of 5 to 20 keV are discussed. The results of an analysis used to optimize the APS ring energy is presented and tunability contours and intensity parameters are presented for two typical classes of devices

Magnetron based high energy S-band linac system

International Nuclear Information System (INIS)

Tiwari, T.; Krishnan, R.; Phatangare, Manoj

2012-01-01

This paper deals with the study of magnetron based high energy S-band linear accelerator (linac) system operating at spot frequency 2.998 GHz. The energy and dose are two important parameters of linac system which depend on input power of microwave source and length of linac tube. Here the author has studied how these parameters can be improved for side coupled standing wave S-band linac system

1-GeV Linac Upgrade Study at Fermilab

International Nuclear Information System (INIS)

Popovic, M.; Moretti, A.; Noble, R.; Schmidt, C.W.

1998-09-01

A linac injector for a new proton source complex at Fermilab is assumed to have a kinetic energy of 1 GeV. This linac would be sized to accelerate 100 mA of H - beam in a 200 microsecond pulse at a 15 Hz repetition rate. This would be adequate to produce ∼10 14 protons per pulse allowing for future improvements of the new proton source complex. An alternate proposal is to add 600 MeV of side coupled cavity linac at 805 MHz to the existing 400 MeV Linac. This addition may either be in a new location or use the present Booster tunnel. A discussion of these possibilities will be given

Photon collisions as a glueball source

International Nuclear Information System (INIS)

Liu, H.C.

1984-01-01

Photon-photon and photon-nucleon collisions are suggested as a glueball source at small x in the collision center-of-mass frame. The glueball-production cross section is estimated through the two-gluon-fusion mechanism in perturbative quantum chromodynamics. The pointlike component of the photon structure function has a distinctive feature in that it consists almost purely of gluons at small x, which turns out to be very effective in producing glueballs. A much larger signal-to-noise ratio is expected in the glueball search in high-energy photon-photon and photon-nucleon collisions compared with hadron-hadron collisions. It is argued that the background due to soft collisions of the photons can be effectively reduced

Advanced Photon Source (APS)

Data.gov (United States)

Federal Laboratory Consortium — The Advanced Photon Source (APS) at the U.S. Department of Energy's Argonne National Laboratoryprovides this nation's (in fact, this hemisphere's) brightest storage...

Integrated design of the SSC linac injector

International Nuclear Information System (INIS)

Evans, D.; Valiecnti, R.; Wood, F.

1992-01-01

The Ion Source, Low Energy Beam Transport (LEBT), and Radio Frequency Quadrupole (RFQ) of the Superconducting Super Collider (SSC) Linac act as a unit (referred to as the Linac Injector), the Ion Source and LEBT being cantilevered off of the RFQ. Immediately adjacent to both ends of the RFQ cavity proper are endwall chambers containing beam instrumentation and independently-operated vacuum isolation valves. The Linac Injector delivers 30 mA of H - beam at 2.5 MeV. This paper describes the design constraints imposed on the endwalls, aspects of the integration of the Ion Source and LEBT including attachment to the RFQ, maintainability and interchangeability of LEBTs, vacuum systems for each component, and the design of necessary support structure. (Author) 2 tab

High field electron linacs

International Nuclear Information System (INIS)

Le Duff, J.

1985-12-01

High field electron linacs are considered as potential candidates to provide very high energies beyond LEP. Since almost twenty years not much improvement has been made on linac technologies as they have been mostly kept at low and medium energies to be used as injectors for storage rings. Today, both their efficiency and their performances are being reconsidered, and for instance the pulse compression sheme developed at SLAC and introduced to upgrade the energy of that linac is a first step towards a new generation of linear accelerators. However this is not enough in terms of power consumption and more development is needed to improve both the efficiency of accelerating structures and the performances of RF power sources

Scoping studies - photon and low energy neutron interrogation

Energy Technology Data Exchange (ETDEWEB)

Becker, G.; Harker, Y.; Jones, J. [LMITCo, Idaho Falls, ID (United States); Harmon, F. [Idaho State Univ., Pocatello, ID (United States)

1997-11-01

High energy photon interrogation of waste containers, with the aim of producing photo nuclear reactions, in specific materials, holds the potential of good penetration and rapid analysis. Compact high energy ({le} 10 MeV) photon sources in the form of electron linacs producing bremstrahlung radiation are readily available. Work with the Varitron variable energy accelerator at ISU will be described. Advantages and limitations of the technique will be discussed. Using positive ion induced neutron producing reactions, it is possible to generate neutrons in a specific energy range. By this means, variable penetration and specific reactions can be excited in the assayed material. Examples using the {sup 3}H(p,n) and {sup 7}Li(p,n) reactions as neutron sources will be discussed. 4 refs., 7 figs.

Klystron modulator operation and upgrades for the APS linac

International Nuclear Information System (INIS)

Russell, T.J.; Cours, A.

1995-01-01

The Advanced Photon Source (APS) linac requires five 100-MW modulators to achieve its required energy. In-house construction of these modulators was under an extremely compressed time schedule and, while the original design was successful, it had a few shortcomings. The operation of the modulators was hindered by excessively sensitive controls and overheating during the hot summer months. The system underwent minor changes that resulted in major improvements. Additionally, improvements have been made to the high voltage circuits to improve the rise time of the output pulse shape. reduce the initial ringing of the pulse, and enhance the reliability of the system. This paper will outline the changes and explain the results of the improvements

Controlling light emission from single-photon sources using photonic nanowires

DEFF Research Database (Denmark)

Gregersen, Niels; Chen, Yuntian; Mørk, Jesper

2012-01-01

The photonic nanowire has recently emerged as an promising alternative to microcavity-based single-photon source designs. In this simple structure, a geometrical effect ensures a strong coupling between an embedded emitter and the optical mode of interest and a combination of tapers and mirrors a...

Electron linac injector developments

International Nuclear Information System (INIS)

Fraser, J.S.

1986-01-01

There is a continuing demand for improved injectors for electron linacs. Free-electron laser (FEL) oscillators require pulse trains of high brightness and, in some applications, high average power at the same time. Wakefield-accelerator and laser-acceleration experiments require isolated bunches of high peak brightness. Experiments with alkali-halide photoemissive and thermionic electron sources in rf cavities for injector applications are described. For isolated pulses, metal photocathodes (illuminated by intense laser pulses) are being employed. Reduced emittance growth in high-peak-current electron injectors may be achieved by linearizing the cavity electric field's radial component and by using high field strengths at the expense of lower shunt impedance. Harmonically excited cavities have been proposed for enlarging the phase acceptance of linac cavities and thereby reducing the energy spread produced in the acceleration process. Operation of injector linacs at a subharmonic of the main linac frequency is also proposed for enlarging the phase acceptance

High gradient linac for proton therapy

Directory of Open Access Journals (Sweden)

S. Benedetti

2017-04-01

Full Text Available Proposed for the first time almost 30 years ago, the research on radio frequency linacs for hadron therapy experienced a sparkling interest in the past decade. The different projects found a common ground on a relatively high rf operating frequency of 3 GHz, taking advantage of the availability of affordable and reliable commercial klystrons at this frequency. This article presents for the first time the design of a proton therapy linac, called TULIP all-linac, from the source up to 230 MeV. In the first part, we will review the rationale of linacs for hadron therapy. We then divided this paper in two main sections: first, we will discuss the rf design of the different accelerating structures that compose TULIP; second, we will present the beam dynamics design of the different linac sections.

Efficient fiber-coupled single-photon source based on quantum dots in a photonic-crystal waveguide

DEFF Research Database (Denmark)

Daveau, Raphaël S.; Balram, Krishna C.; Pregnolato, Tommaso

2017-01-01

Many photonic quantum information processing applications would benefit from a high brightness, fiber-coupled source of triggered single photons. Here, we present a fiber-coupled photonic-crystal waveguide (PCWG) singlephoton source relying on evanescent coupling of the light field from a tapered...

Dosimetry quality audit of high energy photon beams in greek radiotherapy centers

International Nuclear Information System (INIS)

Hourdakis, Constantine J.; Boziari, A.

2008-01-01

Background and purpose: Dosimetry quality audits and intercomparisons in radiotherapy centers is a useful tool in order to enhance the confidence for an accurate therapy and to explore and dissolve discrepancies in dose delivery. This is the first national comprehensive study that has been carried out in Greece. During 2002 - 2006 the Greek Atomic Energy Commission performed a dosimetry quality audit of high energy external photon beams in all (23) Greek radiotherapy centers, where 31 linacs and 13 Co-60 teletherapy units were assessed in terms of their mechanical performance characteristics and relative and absolute dosimetry. Materials and Methods: The quality audit in dosimetry of external photon beams took place by means of on-site visits, where certain parameters of the photon beams were measured, calculated and assessed according to a specific protocol and the IAEA TRS 398 dosimetry code of practice. In each radiotherapy unit (Linac or Co-60), certain functional parameters were measured and the results were compared to tolerance values and limits. Doses in water under reference and non reference conditions were measured and compared to the stated values. Also, the treatment planning systems (TPS) were evaluated with respect to irradiation time calculations. Results: The results of the mechanical tests, dosimetry measurements and TPS evaluation have been presented in this work and discussed in detail. This study showed that Co-60 units had worse performance mechanical characteristics than linacs. 28% of all irradiation units (23% of linacs and 42% of Co-60 units) exceeded the acceptance limit at least in one mechanical parameter. Dosimetry accuracy was much worse in Co60 units than in linacs. 61% of the Co60 units exhibited deviations outside ±3% and 31% outside ±5%. The relevant percentages for the linacs were 24% and 7% respectively. The results were grouped for each hospital and the sources of errors (functional and human) have been investigated and

Dosimetry quality audit of high energy photon beams in greek radiotherapy centers.

Science.gov (United States)

Hourdakis, Constantine J; Boziari, A

2008-04-01

Dosimetry quality audits and intercomparisons in radiotherapy centers is a useful tool in order to enhance the confidence for an accurate therapy and to explore and dissolve discrepancies in dose delivery. This is the first national comprehensive study that has been carried out in Greece. During 2002--2006 the Greek Atomic Energy Commission performed a dosimetry quality audit of high energy external photon beams in all (23) Greek radiotherapy centers, where 31 linacs and 13 Co-60 teletherapy units were assessed in terms of their mechanical performance characteristics and relative and absolute dosimetry. The quality audit in dosimetry of external photon beams took place by means of on-site visits, where certain parameters of the photon beams were measured, calculated and assessed according to a specific protocol and the IAEA TRS 398 dosimetry code of practice. In each radiotherapy unit (Linac or Co-60), certain functional parameters were measured and the results were compared to tolerance values and limits. Doses in water under reference and non reference conditions were measured and compared to the stated values. Also, the treatment planning systems (TPS) were evaluated with respect to irradiation time calculations. The results of the mechanical tests, dosimetry measurements and TPS evaluation have been presented in this work and discussed in detail. This study showed that Co-60 units had worse performance mechanical characteristics than linacs. 28% of all irradiation units (23% of linacs and 42% of Co-60 units) exceeded the acceptance limit at least in one mechanical parameter. Dosimetry accuracy was much worse in Co60 units than in linacs. 61% of the Co60 units exhibited deviations outside +/-3% and 31% outside +/-5%. The relevant percentages for the linacs were 24% and 7% respectively. The results were grouped for each hospital and the sources of errors (functional and human) have been investigated and discussed in details. This quality audit proved to be a

Operating experience with the ALS linac

International Nuclear Information System (INIS)

Selph, F.; Massoletti, D.

1991-05-01

The linac injector for the Advanced Light Source (ALS) at LBL was recently put into operation. Energy is 50 MeV, frequency 3 GHz. The electron gun delivers up to 6nC in a 3.0-ns bunch at 120 kV. A train of bunches is injected into a 1-Hz booster and accelerated to 1.5 GHz for storage ring injection. A magnetic analysis system is used for optimizing the linac. Measured beam properties from the gun and after acceleration in the linac are described. 9 refs., 3 figs

Single photon sources with single semiconductor quantum dots

Science.gov (United States)

Shan, Guang-Cun; Yin, Zhang-Qi; Shek, Chan Hung; Huang, Wei

2014-04-01

In this contribution, we briefly recall the basic concepts of quantum optics and properties of semiconductor quantum dot (QD) which are necessary to the understanding of the physics of single-photon generation with single QDs. Firstly, we address the theory of quantum emitter-cavity system, the fluorescence and optical properties of semiconductor QDs, and the photon statistics as well as optical properties of the QDs. We then review the localization of single semiconductor QDs in quantum confined optical microcavity systems to achieve their overall optical properties and performances in terms of strong coupling regime, efficiency, directionality, and polarization control. Furthermore, we will discuss the recent progress on the fabrication of single photon sources, and various approaches for embedding single QDs into microcavities or photonic crystal nanocavities and show how to extend the wavelength range. We focus in particular on new generations of electrically driven QD single photon source leading to high repetition rates, strong coupling regime, and high collection efficiencies at elevated temperature operation. Besides, new developments of room temperature single photon emission in the strong coupling regime are reviewed. The generation of indistinguishable photons and remaining challenges for practical single-photon sources are also discussed.

Modelling of electron contamination in clinical photon beams for Monte Carlo dose calculation

International Nuclear Information System (INIS)

Yang, J; Li, J S; Qin, L; Xiong, W; Ma, C-M

2004-01-01

The purpose of this work is to model electron contamination in clinical photon beams and to commission the source model using measured data for Monte Carlo treatment planning. In this work, a planar source is used to represent the contaminant electrons at a plane above the upper jaws. The source size depends on the dimensions of the field size at the isocentre. The energy spectra of the contaminant electrons are predetermined using Monte Carlo simulations for photon beams from different clinical accelerators. A 'random creep' method is employed to derive the weight of the electron contamination source by matching Monte Carlo calculated monoenergetic photon and electron percent depth-dose (PDD) curves with measured PDD curves. We have integrated this electron contamination source into a previously developed multiple source model and validated the model for photon beams from Siemens PRIMUS accelerators. The EGS4 based Monte Carlo user code BEAM and MCSIM were used for linac head simulation and dose calculation. The Monte Carlo calculated dose distributions were compared with measured data. Our results showed good agreement (less than 2% or 2 mm) for 6, 10 and 18 MV photon beams

Resonant excitation of high order modes in the 3.9 GHz cavity of the Linac Coherent Light Source

Science.gov (United States)

Lunin, A.; Khabiboulline, T.; Solyak, N.; Sukhanov, A.; Yakovlev, V.

2018-02-01

Construction of the Linac Coherent Light Source II (LCLS-II) is underway for the world's first hard x-ray free-electron laser. A central part of the LCLS-II project is a 4 GeV superconducting radio frequency electron linac that will operate in the continuous wave (cw) mode. The linac is segmented into four sections named as L 0 , L 1 , L 2 , and L 3 . Two 3.9 GHz cryomodules, each housing of eight third-harmonic cavities similar to the cavities developed for the European X-ray Free Electron Laser (XFEL), will be used in section L 1 of the linac for linearizing the longitudinal beam profile. In this paper, we present a study of trapped high order modes (HOMs) excited by a cw electron beam in the third-harmonic cavities of the LCLS-II linac. A detailed comparison of the original XFEL design and the LCLS-II design with a modified end group is performed in order to estimate the effect of a reduced beam pipe aperture on the efficiency of HOM damping. Furthermore, we apply a statistical analysis of the eigenmode spectrum for the estimation of the probability of resonant HOM losses and influence of HOMs on beam dynamics.

Modeling and Design of High-Efficiency Single-Photon Sources

DEFF Research Database (Denmark)

Gregersen, Niels; Nielsen, Per Kær; Mørk, Jesper

2013-01-01

be electrically driven. Several design strategies addressing these requirements have been proposed. In the cavity-based source, light emission is controlled using resonant cavity quantum electrodynamics effects, whereas in the waveguide-based source, broadband electric field screening effects are employed......Solid-state sources capable of emitting single photons on demand are of great interest in quantum information applications. Ideally, such a source should emit exactly one photon into the collection optics per trigger, the emitted photons should be indistinguishable, and the source should...

MCMEG: Simulations of both PDD and TPR for 6 MV LINAC photon beam using different MC codes

Science.gov (United States)

Fonseca, T. C. F.; Mendes, B. M.; Lacerda, M. A. S.; Silva, L. A. C.; Paixão, L.; Bastos, F. M.; Ramirez, J. V.; Junior, J. P. R.

2017-11-01

The Monte Carlo Modelling Expert Group (MCMEG) is an expert network specializing in Monte Carlo radiation transport and the modelling and simulation applied to the radiation protection and dosimetry research field. For the first inter-comparison task the group launched an exercise to model and simulate a 6 MV LINAC photon beam using the Monte Carlo codes available within their laboratories and validate their simulated results by comparing them with experimental measurements carried out in the National Cancer Institute (INCA) in Rio de Janeiro, Brazil. The experimental measurements were performed using an ionization chamber with calibration traceable to a Secondary Standard Dosimetry Laboratory (SSDL). The detector was immersed in a water phantom at different depths and was irradiated with a radiation field size of 10×10 cm2. This exposure setup was used to determine the dosimetric parameters Percentage Depth Dose (PDD) and Tissue Phantom Ratio (TPR). The validation process compares the MC calculated results to the experimental measured PDD20,10 and TPR20,10. Simulations were performed reproducing the experimental TPR20,10 quality index which provides a satisfactory description of both the PDD curve and the transverse profiles at the two depths measured. This paper reports in detail the modelling process using MCNPx, MCNP6, EGSnrc and Penelope Monte Carlo codes, the source and tally descriptions, the validation processes and the results.

The Superconducting Super Collider (SSC) linac

International Nuclear Information System (INIS)

Watson, J.M.

1990-09-01

The preliminary design of the 600 MeV H - linac for the Superconducting Super Collider injector is described. The linac must provide a 25 mA beam during 7--35 μs macropulses at Hz within injection bursts. Normalized transverse emittances of less than 0.5 π mm-mrad (rms) are required for injection into the Low Energy Booster synchrotron. Cost, ease of commissioning, and operational reliability are important considerations. The linac will consists of an H - source with electrostatic LEBT, 2.5 MeV radiofrequency quadrupole accelerator, a 70 MeV drift-tube linac, and 530 MeV and the side-coupled linac operates at 1284 MHz. A modest total length of 150 m results from the tradeoff between cost optimization and reliability. The expected performance from beam dynamics simulations and the status of the project are described. 11 refs., 1 fig., 6 tabs

Large aperture contact ionized Cs+1 ion source for an induction linac

International Nuclear Information System (INIS)

Abbott, S.; Chupp, W.; Faltens, A.; Herrmannsfeldt, W.; Hoyer, E.; Keefe, D.; Kim, C.H.; Rosenblum, S.; Shiloh, J.

1979-03-01

A 500 KeV one-ampere Cs +1 ion beam has been generated by contact ionization with a 30 cm dia. iridium hot plate. Reproducibility of space charge limited ion current wave forms at repetition rates up to 1 Hz has been verified. The beam is characterized to be very bright and suitable as an ion source for the induction linac based heavy ion fusion scheme. The hot anode plate was found to be reliable and self-cleaning during the operation

Experimental benchmark of the NINJA code for application to the Linac4 H- ion source plasma

Science.gov (United States)

Briefi, S.; Mattei, S.; Rauner, D.; Lettry, J.; Tran, M. Q.; Fantz, U.

2017-10-01

For a dedicated performance optimization of negative hydrogen ion sources applied at particle accelerators, a detailed assessment of the plasma processes is required. Due to the compact design of these sources, diagnostic access is typically limited to optical emission spectroscopy yielding only line-of-sight integrated results. In order to allow for a spatially resolved investigation, the electromagnetic particle-in-cell Monte Carlo collision code NINJA has been developed for the Linac4 ion source at CERN. This code considers the RF field generated by the ICP coil as well as the external static magnetic fields and calculates self-consistently the resulting discharge properties. NINJA is benchmarked at the diagnostically well accessible lab experiment CHARLIE (Concept studies for Helicon Assisted RF Low pressure Ion sourcEs) at varying RF power and gas pressure. A good general agreement is observed between experiment and simulation although the simulated electron density trends for varying pressure and power as well as the absolute electron temperature values deviate slightly from the measured ones. This can be explained by the assumption of strong inductive coupling in NINJA, whereas the CHARLIE discharges show the characteristics of loosely coupled plasmas. For the Linac4 plasma, this assumption is valid. Accordingly, both the absolute values of the accessible plasma parameters and their trends for varying RF power agree well in measurement and simulation. At varying RF power, the H- current extracted from the Linac4 source peaks at 40 kW. For volume operation, this is perfectly reflected by assessing the processes in front of the extraction aperture based on the simulation results where the highest H- density is obtained for the same power level. In surface operation, the production of negative hydrogen ions at the converter surface can only be considered by specialized beam formation codes, which require plasma parameters as input. It has been demonstrated that

Status of the RF-driven H− ion source for J-PARC linac

International Nuclear Information System (INIS)

Oguri, H.; Ohkoshi, K.; Ikegami, K.; Takagi, A.; Asano, H.; Ueno, A.; Shibata, T.

2016-01-01

For the upgrade of the Japan Proton Accelerator Research Complex linac beam current, a cesiated RF-driven negative hydrogen ion source was installed during the 2014 summer shutdown period, with subsequent operations commencing on September 29, 2014. The ion source has been successfully operating with a beam current and duty factor of 33 mA and 1.25% (500 μs and 25 Hz), respectively. The result of recent beam operation has demonstrated that the ion source is capable of continuous operation for approximately 1100 h. The spark rate at the beam extractor was observed to be at a frequency of less than once a day, which is an acceptable level for user operation. Although an antenna failure occurred during operation on October 26, 2014, no subsequent serious issues have occurred since then

Single-photon sources based on single molecules in solids

International Nuclear Information System (INIS)

Moerner, W E

2004-01-01

Single molecules in suitable host crystals have been demonstrated to be useful single-photon emitters both at liquid-helium temperatures and at room temperature. The low-temperature source achieved controllable emission of single photons from a single terrylene molecule in p-terphenyl by an adiabatic rapid passage technique. In contrast with almost all other single-molecule systems, terrylene single molecules show extremely high photostability under continuous, high-intensity irradiation. A room-temperature source utilizing this material has been demonstrated, in which fast pumping into vibrational sidebands of the electronically excited state achieved efficient inversion of the emissive level. This source yielded a single-photon emission probability p(1) of 0.86 at a detected count rate near 300 000 photons s -1 , with very small probability of emission of more than one photon. Thus, single molecules in solids can be considered as contenders for applications of single-photon sources such as quantum key distribution

Accelerator study note: An attempt of 1 GeV linac

International Nuclear Information System (INIS)

Kato, Takao.

1987-01-01

A hypothetical 1 GeV linac is described, including its structure (which includes an ion source, radio frequency quadrupole linac, drift type linac, and coupled cavity linac), criteria for optimized design, cost optimization, frequency dependability of high frequency electric power loss, tuning during operation, the general rf system, computer codes and example calculations, beam dynamics simulation, and reduction of energy spread through the use of a debuncher

Research and development toward a 4.5-1.5{angstrom} linac coherent light source (LCLS) at SLAC

Energy Technology Data Exchange (ETDEWEB)

Tatchyn, R.; Arthur, J.; Baltay, M. [Stanford Univ., CA (United States)] [and others

1995-12-31

In recent years significant studies have been initiated on the theoretical and technical feasibility of utilizing a portion of the 3km S-band accelerator at the Stanford Linear Accelerator Center (SLAC) to drive a short wavelength (4.5-1.5 {Angstrom}) Linac Coherent Light Source (LCLS), a Free-Electron Laser (FEL) operating in the Self-Amplified Spontaneous Emission (SASE) regime. Electron beam requirements for single-pass saturation include: (1) a peak current in the 3-7 kA range, (2) a relative energy spread of <0.05%, ad (3) a transverse emittance, {epsilon}{le}{lambda}/4{pi}, where {lambda}[m] is the output wavelength. Requirements on the insertion device include field error levels of 0.1-0.2% for keeping the electron bunch centered on and in phase with the amplified photons, and a focusing beta of 4-8 m for inhibiting the dilution of its transverse density. Although much progress techniques necessary for LCLS operation down to {approximately}20 {angstrom}, a substantial amount of research and development is still required in a number of theoretical and experimental areas leading to the construction and operation of a 4.5-1.5 {angstrom} LCLS. In this paper we report on a research and development program underway and in planning at SLAC for addressing critical questions in these areas. These include the construction and operation of a linac test stand for developing laser-driven photocathode rf guns with normalized emittances approaching 1 mm-mr; development of advanced beam compression, stability, an emittance control techniques at multi-GeV energies; the construction and operation of a FEL Amplifier Test Experiment (FATE) for theoretical and experimental studies of SASE at IR wavelengths; an undulator development program to investigate superconducting, hybrid/permanent magnet (hybrid/PM), and pulsed-Cu technologies; theoretical and computational studies of high-gain FEL physics and LCLS component designs.

SLAC Linac Preparations for FACET

International Nuclear Information System (INIS)

Erickson, Roger

2011-01-01

The SLAC 3km linear electron accelerator has been cut at the two-thirds point to provide beams to two independent programs. The last third provides the electron beam for the Linac Coherent Light Source (LCLS), leaving the first two-thirds available for FACET, the new experimental facility for accelerator science and test beams. In this paper, we describe this separation and projects to prepare the linac for the FACET experimental program.

A high-efficiency electrically-pumped single-photon source based on a photonics nanowire

DEFF Research Database (Denmark)

Gregersen, Niels; Nielsen, Torben Roland; Mørk, Jesper

An electrically-pumped single-photon source design with a predicted efficiency of 89% is proposed. The design is based on a quantum dot embedded in a photonic nanowire with tailored ends and optimized contact electrodes. Unlike cavity-based approaches, the photonic nanowire features broadband...

A time-of-flight detector for thermal neutrons from radiotherapy Linacs

Energy Technology Data Exchange (ETDEWEB)

Conti, V. [Universita degli Studi di Milano and INFN di Milano (Italy)], E-mail: conti.Valentina@gmail.com; Bartesaghi, G. [Universita degli Studi di Milano and INFN di Milano (Italy); Bolognini, D.; Mascagna, V.; Perboni, C.; Prest, M.; Scazzi, S. [Universita dell' Insubria, Como and INFN di Milano (Italy); Mozzanica, A. [Universita degli Studi di Brescia and INFN sezione di Pavia (Italy); Cappelletti, P.; Frigerio, M.; Gelosa, S.; Monti, A.; Ostinelli, A. [Fisica Sanitaria, Ospedale S. Anna di Como (Italy); Giannini, G.; Vallazza, E. [INFN, sezione di Trieste and Universita degli Studi di Trieste (Italy)

2007-10-21

Boron Neutron Capture Therapy (BNCT) is a therapeutic technique exploiting the release of dose inside the tumour cell after a fission of a {sup 10}B nucleus following the capture of a thermal neutron. BNCT could be the treatment for extended tumors (liver, stomach, lung), radio-resistant ones (melanoma) or tumours surrounded by vital organs (brain). The application of BNCT requires a high thermal neutron flux (>5x10{sup 8}ncm{sup -2}s{sup -1}) with the correct energy spectrum (neutron energy <10keV), two requirements that for the moment are fulfilled only by nuclear reactors. The INFN PhoNeS (Photo Neutron Source) project is trying to produce such a neutron beam with standard radiotherapy Linacs, maximizing with a dedicated photo-neutron converter the neutrons produced by Giant Dipole Resonance by a high energy (>8MeV) photon beam. In this framework, we have developed a real-time detector to measure the thermal neutron time-of -flight to compute the flux and the energy spectrum. Given the pulsed nature of Linac beams, the detector is a single neutron counting system made of a scintillator detecting the photon emitted after the neutron capture by the hydrogen nuclei. The scintillator signal is sampled by a dedicated FPGA clock thus obtaining the exact arrival time of the neutron itself. The paper will present the detector and its electronics, the feasibility measurements with a Varian Clinac 1800/2100CD and comparison with a Monte Carlo simulation.

SU-E-T-238: Deriving Electron Contamination Spectra From Pure and Clinical Photon Beams

International Nuclear Information System (INIS)

Smit, C; Plessis, F du

2015-01-01

Purpose: To extract the electron contamination energy spectra for an Elekta Precise Linac, based on pure photon and measured clinical beam percentage depth dose data. And to include this as an additional source in isource 4 in DOSXYZnrc. Methods: A pure photon beam was simulated for the Linac using isource 4 in the DOSXYZnrc Monte Carlo (MC) code. Percentage depth dose (PDD) data were extracted afterwards for a range of field sizes (FS). These simulated dose data were compared to actual measured dose PDD data, with the data normalized at 10 cm depth. The resulting PDD data resembled the electron contamination depth dose. Since the dose fall-off is a strictly decreasing function, a method was adopted to derive the contamination electron spectrum. Afterwards this spectrum was used in a DOSXYZnrc MC simulation run to verify that the original electron depth dose could be replicated. Results: Various square aperture FS’s for 6, 8 and 15 megavolt (MV) photon beams were modeled, simulated and compared to their respective actual measured PDD data. As FS increased, simulated pure photon depth-dose profiles shifted deeper, thus requiring electron contamination to increase the surface dose. The percentage of electron weight increased with increase in FS. For a FS of 15×15 cm 2 , the percentage electron weight is 0.1%, 0.2% and 0.4% for 6, 8 and 15 MV beams respectively. Conclusion: From the PDD results obtained, an additional electron contamination source was added to the photon source model so that simulation and measured PDD data could match within 2 % / 2 mm gamma-index criteria. The improved source model could assure more accurate simulations of surface doses. This research project was funded by the South African Medical Research Council (MRC) with funds from National Treasury under its Economic Competitiveness and Support package

SU-E-T-238: Deriving Electron Contamination Spectra From Pure and Clinical Photon Beams

Energy Technology Data Exchange (ETDEWEB)

Smit, C; Plessis, F du [University of the Free State, Bloemfontein, Free State (South Africa)

2015-06-15

Purpose: To extract the electron contamination energy spectra for an Elekta Precise Linac, based on pure photon and measured clinical beam percentage depth dose data. And to include this as an additional source in isource 4 in DOSXYZnrc. Methods: A pure photon beam was simulated for the Linac using isource 4 in the DOSXYZnrc Monte Carlo (MC) code. Percentage depth dose (PDD) data were extracted afterwards for a range of field sizes (FS). These simulated dose data were compared to actual measured dose PDD data, with the data normalized at 10 cm depth. The resulting PDD data resembled the electron contamination depth dose. Since the dose fall-off is a strictly decreasing function, a method was adopted to derive the contamination electron spectrum. Afterwards this spectrum was used in a DOSXYZnrc MC simulation run to verify that the original electron depth dose could be replicated. Results: Various square aperture FS’s for 6, 8 and 15 megavolt (MV) photon beams were modeled, simulated and compared to their respective actual measured PDD data. As FS increased, simulated pure photon depth-dose profiles shifted deeper, thus requiring electron contamination to increase the surface dose. The percentage of electron weight increased with increase in FS. For a FS of 15×15 cm{sup 2}, the percentage electron weight is 0.1%, 0.2% and 0.4% for 6, 8 and 15 MV beams respectively. Conclusion: From the PDD results obtained, an additional electron contamination source was added to the photon source model so that simulation and measured PDD data could match within 2 % / 2 mm gamma-index criteria. The improved source model could assure more accurate simulations of surface doses. This research project was funded by the South African Medical Research Council (MRC) with funds from National Treasury under its Economic Competitiveness and Support package.

Beam Loss in Linacs

CERN Document Server

Plum, M.A.

2016-01-01

Beam loss is a critical issue in high-intensity accelerators, and much effort is expended during both the design and operation phases to minimize the loss and to keep it to manageable levels. As new accelerators become ever more powerful, beam loss becomes even more critical. Linacs for H- ion beams, such as the one at the Oak Ridge Spallation Neutron Source, have many more loss mechanisms compared to H+ (proton) linacs, such as the one being designed for the European Spallation Neutron Source. Interesting H- beam loss mechanisms include residual gas stripping, H+ capture and acceleration, field stripping, black-body radiation and the recently discovered intra-beam stripping mechanism. Beam halo formation, and ion source or RF turn on/off transients, are examples of beam loss mechanisms that are common for both H+ and H- accelerators. Machine protection systems play an important role in limiting the beam loss.

High-quality asynchronous heralded single-photon source at telecom wavelength

International Nuclear Information System (INIS)

Fasel, Sylvain; Alibart, Olivier; Tanzilli, Sebastien; Baldi, Pascal; Beveratos, Alexios; Gisin, Nicolas; Zbinden, Hugo

2004-01-01

We report on the experimental realization and characterization of an asynchronous heralded single-photon source based on spontaneous parametric down-conversion. Photons at 1550 nm are heralded as being inside a single-mode fibre with more than 60% probability, and the multi-photon emission probability is reduced by a factor of up to more than 500 compared to Poissonian light sources. These figures of merit, together with the choice of telecom wavelength for the heralded photons, are compatible with practical applications needing very efficient and robust single-photon sources

Photon Factory activity report, 1990

International Nuclear Information System (INIS)

1991-01-01

The Photon Factory has grown at a considerable rate, and 600 experiments are carried out in 1991, while the number of users is now 2300 including about 500 from industrial sectors. The use of synchrotron radiation increased from fundamental research to industrial development. The development at the Photon Factory is supported by the capability of the accelerators. At present, the 2.5 GeV PF ring is operated with positrons at the initial beam current of 350 mA. The total operation time was 3500 hours in the fiscal year 1990. The development of an avalanche mode photodiode, the observation of quantum beat in the experiment of nuclear Bragg scattering, the measurement of photo-electron and photo-ion spectroscopy were carried out. The conversion of TRISTAN main ring to an ultrahigh brilliance and high coherence source is planned for the future. The annual PF Symposium was held, and Professor H. Winick gave the lecture 'Ultrahigh brightness and coherent radiation from large storage rings'. In this report, the outline of the Photon Factory and the activities in Divisions of Injector Linac, Light Source and Instrumentation are described. (K.I.)

The LINAC4 Project at CERN

CERN Document Server

Arnaudon, L; Bertone, C; Body, Y; Broere, J; Brunner, O; Buzio, M; Carli, C; Caspers, F; Corso, JP; Coupard, J; Dallocchio, A; Dos Santos, N; Garoby, R; Gerigk, F; Hammouti, L; Hanke, K; Jones, M; Kozsar, I; Lettry, J; Lallement, JB; Lombardi, A; Lopez-Hernandez, LA; Maglioni, C; Mathot, S; Maury, S; Mikulec, B; Nisbet, D; Noels, C; Paoluzzi, M; Puccio, B; Raich, U; Ramberger, S; Rossi, C; Schwerg, N; Scrivens, R; Vandoni, G; Weisz, S; Vollaire, J; Vretenar, M; Zickler, T

2011-01-01

As the first step of a long-term programme aiming at an increase in the LHC luminosity, CERN is building a new 160 MeV H¯ linear accelerator, Linac4, to replace the ageing 50 MeV Linac2 as injector to the PS Booster (PSB). Linac4 is an 86-m long normal-conducting linac made of an H¯ source, a Radio Frequency Quadrupole (RFQ), a chopping line and a sequence of three accelerating structures: a Drift-Tube Linac (DTL), a Cell-Coupled DTL (CCDTL) and a Pi-Mode Structure (PIMS). The civil engineering has been recently completed, and construction of the main accelerator components has started with the support of a network of international collaborations. The low-energy section up to 3 MeV including a 3-m long 352 MHz RFQ entirely built at CERN is in the final construction phase and is being installed on a dedicated test stand. The present schedule foresees beam commissioning of the accelerator in the new tunnel in 2013/14; the moment of connection of the new linac to the CERN accelerator chain will depend on the L...

Resonant excitation of high order modes in the 3.9 GHz cavity of the Linac Coherent Light Source

Directory of Open Access Journals (Sweden)

A. Lunin

2018-02-01

Full Text Available Construction of the Linac Coherent Light Source II (LCLS-II is underway for the world’s first hard x-ray free-electron laser. A central part of the LCLS-II project is a 4 GeV superconducting radio frequency electron linac that will operate in the continuous wave (cw mode. The linac is segmented into four sections named as L0, L1, L2, and L3. Two 3.9 GHz cryomodules, each housing of eight third-harmonic cavities similar to the cavities developed for the European X-ray Free Electron Laser (XFEL, will be used in section L1 of the linac for linearizing the longitudinal beam profile. In this paper, we present a study of trapped high order modes (HOMs excited by a cw electron beam in the third-harmonic cavities of the LCLS-II linac. A detailed comparison of the original XFEL design and the LCLS-II design with a modified end group is performed in order to estimate the effect of a reduced beam pipe aperture on the efficiency of HOM damping. Furthermore, we apply a statistical analysis of the eigenmode spectrum for the estimation of the probability of resonant HOM losses and influence of HOMs on beam dynamics.

Single-photon source engineering using a Modal Method

DEFF Research Database (Denmark)

Gregersen, Niels

Solid-state sources of single indistinguishable photons are of great interest for quantum information applications. The semiconductor quantum dot embedded in a host material represents an attractive platform to realize such a single-photon source (SPS). A near-unity efficiency, defined as the num...... nanowire SPSs...

Accelerator-driven X-ray Sources

Energy Technology Data Exchange (ETDEWEB)

Nguyen, Dinh Cong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2015-11-09

After an introduction which mentions x-ray tubes and storage rings and gives a brief review of special relativity, the subject is treated under the following topics and subtopics: synchrotron radiation (bending magnet radiation, wiggler radiation, undulator radiation, brightness and brilliance definition, synchrotron radiation facilities), x-ray free-electron lasers (linac-driven X-ray FEL, FEL interactions, self-amplified spontaneous emission (SASE), SASE self-seeding, fourth-generation light source facilities), and other X-ray sources (energy recovery linacs, Inverse Compton scattering, laser wakefield accelerator driven X-ray sources. In summary, accelerator-based light sources cover the entire electromagnetic spectrum. Synchrotron radiation (bending magnet, wiggler and undulator radiation) has unique properties that can be tailored to the users’ needs: bending magnet and wiggler radiation is broadband, undulator radiation has narrow spectral lines. X-ray FELs are the brightest coherent X-ray sources with high photon flux, femtosecond pulses, full transverse coherence, partial temporal coherence (SASE), and narrow spectral lines with seeding techniques. New developments in electron accelerators and radiation production can potentially lead to more compact sources of coherent X-rays.

Beam Characterization of 10-MV Photon Beam from Medical Linear Accelerator without Flattening Filter.

Science.gov (United States)

Shimozato, Tomohiro; Aoyama, Yuichi; Matsunaga, Takuma; Tabushi, Katsuyoshi

2017-01-01

This work investigated the dosimetric properties of a 10-MV photon beam emitted from a medical linear accelerator (linac) with no flattening filter (FF). The aim of this study is to analyze the radiation fluence and energy emitted from the flattening filter free (FFF) linac using Monte Carlo (MC) simulations. The FFF linac was created by removing the FF from a linac in clinical use. Measurements of the depth dose (DD) and the off-axis profile were performed using a three-dimensional water phantom with an ionization chamber. A MC simulation for a 10-MV photon beam from this FFF linac was performed using the BEAMnrc code. The off-axis profiles for the FFF linac exhibited a chevron-like distribution, and the dose outside the irradiation field was found to be lower for the FFF linac than for a linac with an FF (FF linac). The DD curves for the FFF linac included many contaminant electrons in the build-up region. Therefore, for clinical use, a metal filter is additionally required to reduce the effects of the electron contamination. The mean energy of the FFF linac was found to be lower than that of the FF linac owing to the absence of beam hardening caused by the FF.

Photon acceleration-based radiation sources

International Nuclear Information System (INIS)

Hoffman, J. R.; Muggli, P.; Katsouleas, T.; Mori, W. B.; Joshi, C.

1999-01-01

The acceleration and deceleration of photons in a plasma provides the means for a series of new radiation sources. Previous work on a DC to AC Radiation Converter (DARC source) has shown variable acceleration of photons having zero frequency (i.e., an electrostatic field) to between 6 and 100 GHz (1-3). These sources all had poor guiding characteristics resulting in poor power coupling from the source to the load. Continuing research has identified a novel way to integrate the DARC source into a waveguide. The so called ''pin structure'' uses stainless steel pins inserted through the narrow side of an X band waveguide to form the electrostatic field pattern (k≠0, ω=0). The pins are spaced such that the absorption band resulting from this additional periodic structure is outside of the X band range (8-12 GHz), in which the normal waveguide characteristics are left unchanged. The power of this X band source is predicted theoretically to scale quadratically with the pin bias voltage as -800 W/(kV) 2 and have a pulse width of -1 ns. Cold tests and experimental results are presented. Applications for a high power, short pulse radiation source extends to the areas of landmine detection, improved radar resolution, and experimental investigations of molecular systems

Protecting single-photon entanglement with practical entanglement source

Science.gov (United States)

Zhou, Lan; Ou-Yang, Yang; Wang, Lei; Sheng, Yu-Bo

2017-06-01

Single-photon entanglement (SPE) is important for quantum communication and quantum information processing. However, SPE is sensitive to photon loss. In this paper, we discuss a linear optical amplification protocol for protecting SPE. Different from the previous protocols, we exploit the practical spontaneous parametric down-conversion (SPDC) source to realize the amplification, for the ideal entanglement source is unavailable in current quantum technology. Moreover, we prove that the amplification using the entanglement generated from SPDC source as auxiliary is better than the amplification assisted with single photons. The reason is that the vacuum state from SPDC source will not affect the amplification, so that it can be eliminated automatically. This protocol may be useful in future long-distance quantum communications.

Finite element thermal study of the Linac4 plasma generator

International Nuclear Information System (INIS)

Faircloth, D.; Kronberger, M.; Kuechler, D.; Lettry, J.; Scrivens, R.

2010-01-01

The temperature distribution and heat flow at equilibrium of the plasma generator of the rf-powered noncesiated Linac4 H - ion source have been studied with a finite element model. It is shown that the equilibrium temperatures obtained in the Linac4 nominal operation mode (100 kW rf power, 2 Hz repetition rate, and 0.4 ms pulse duration) are within material specifications except for the magnet cage, where a redesign may be necessary. To assess the upgrade of the Linac4 source for operation in the high-power operation mode of the Superconducting Proton Linac (SPL), an extrapolation of the heat load toward 100 kW rf power, 50 Hz repetition rate, and 0.4 ms pulse duration has been performed. The results indicate that a significant improvement of the source cooling is required to allow for operation in the high-power mode of SPL.

Finite element thermal study of the Linac4 plasma generator

Energy Technology Data Exchange (ETDEWEB)

Faircloth, D. [STFC, Rutherford Appleton Laboratory, Chilton, Oxon OX11 0QX (United Kingdom); Kronberger, M.; Kuechler, D.; Lettry, J.; Scrivens, R. [BE-ABP, Hadron Sources and Linacs, CERN, CH-1211 Geneva (Switzerland)

2010-02-15

The temperature distribution and heat flow at equilibrium of the plasma generator of the rf-powered noncesiated Linac4 H{sup -} ion source have been studied with a finite element model. It is shown that the equilibrium temperatures obtained in the Linac4 nominal operation mode (100 kW rf power, 2 Hz repetition rate, and 0.4 ms pulse duration) are within material specifications except for the magnet cage, where a redesign may be necessary. To assess the upgrade of the Linac4 source for operation in the high-power operation mode of the Superconducting Proton Linac (SPL), an extrapolation of the heat load toward 100 kW rf power, 50 Hz repetition rate, and 0.4 ms pulse duration has been performed. The results indicate that a significant improvement of the source cooling is required to allow for operation in the high-power mode of SPL.

High-field strong-focusing undulator designs for X-ray Linac Coherent Light Source (LCLS) applications

International Nuclear Information System (INIS)

Caspi, S.; Schlueter, R.; Tatchyn, R.

1995-01-01

Linac-driven X-Ray Free Electron Lasers (e.g., Linac Coherent Light Sources (LCLSs)), operating on the principle of single-pass saturation in the Self-Amplified Spontaneous Emission (SASE) regime typically require multi-GeV beam energies and undulator lengths in excess of tens of meters to attain sufficient gain in the 1 angstrom--0.1 angstrom range. In this parameter regime, the undulator structure must provide: (1) field amplitudes B 0 in excess of 1T within periods of 4cm or less, (2) peak on-axis focusing gradients on the order of 30T/m, and (3) field quality in the 0.1%--0.3% range. In this paper the authors report on designs under consideration for a 4.5--1.5 angstrom LCLS based on superconducting (SC), hybrid/PM, and pulsed-Cu technologies

LINAC4 low energy beam measurements

CERN Document Server

Hein, L M; Lallement, J B; Lombardi, A M; Midttun, O; Posocco, P; Scrivens, R

2012-01-01

Linac4 is a 160 MeV normal-conducting linear accelerator for negative Hydrogen ions (H−), which will replace the 50 MeV proton Linac (Linac2) as linear injector for the CERN accelerators. The low energy part, comprising a 45 keV Low Energy Beam Transport system (LEBT), a 3 MeV Radiofrequency Quadrupole (RFQ) and a Medium Energy Beam Transport (MEBT) is being assembled in a dedicated test stand for pre-commissioning with a proton beam. During 2011 extensive measurements were done after the source and after the LEBT with the aim of preparing the RFQ commissioning and validating the simulation tools, indispensable for future source upgrades. The measurements have been thoroughly simulated with a multi-particle code, including 2D magnetic field maps, error studies, steering studies and the generation of beam distribution from measurements. Emittance, acceptance and transmission measurements will be presented and compared to the results of the simulations.

Development of C6+ laser ion source and RFQ linac for carbon ion radiotherapy

Science.gov (United States)

Sako, T.; Yamaguchi, A.; Sato, K.; Goto, A.; Iwai, T.; Nayuki, T.; Nemoto, K.; Kayama, T.; Takeuchi, T.

2016-02-01

A prototype C6+ injector using a laser ion source has been developed for a compact synchrotron dedicated to carbon ion radiotherapy. The injector consists of a laser ion source and a 4-vane radio-frequency quadrupole (RFQ) linac. Ion beams are extracted from plasma and directly injected into the RFQ. A solenoid guides the low-energy beams into the RFQ. The RFQ is designed to accelerate high-intensity pulsed beams. A structure of monolithic vanes and cavities is adopted to reduce its power consumption. In beam acceleration tests, a solenoidal magnetic field set between the laser ion source and the RFQ helped increase both the peak currents before and after the RFQ by a factor of 4.

Development of C6+ laser ion source and RFQ linac for carbon ion radiotherapy

International Nuclear Information System (INIS)

Sako, T.; Yamaguchi, A.; Sato, K.; Goto, A.; Iwai, T.; Nayuki, T.; Nemoto, K.; Kayama, T.; Takeuchi, T.

2016-01-01

A prototype C 6+ injector using a laser ion source has been developed for a compact synchrotron dedicated to carbon ion radiotherapy. The injector consists of a laser ion source and a 4-vane radio-frequency quadrupole (RFQ) linac. Ion beams are extracted from plasma and directly injected into the RFQ. A solenoid guides the low-energy beams into the RFQ. The RFQ is designed to accelerate high-intensity pulsed beams. A structure of monolithic vanes and cavities is adopted to reduce its power consumption. In beam acceleration tests, a solenoidal magnetic field set between the laser ion source and the RFQ helped increase both the peak currents before and after the RFQ by a factor of 4

Linac design for the LCLS project at SLAC

International Nuclear Information System (INIS)

Bharadwaj, V.K.; Bane, K.; Clendenin, J.

1997-05-01

The Linac Coherent Light Source (LCLS) at SLAC is being designed to produce intense, coherent 0.15-nm x-rays. These x-rays will be produced by a single pass of a 15 GeV bunched electron beam through a long undulator. Nominally, the bunches have a charge of 1 nC, normalized transverse emittances of less than 1.5π mm-mr and an rms bunch length of 20 μm. The electron beam will be produced using the last third of the SLAC 3-km linac in a manner compatible with simultaneous operation of the remainder of the linac for PEP-II. The linac design necessary to produce an electron beam with the required brightness for LCLS is discussed, and the specific linac modifications are described

Optimization of Beam Transmission of PAL-PNF Electron Linac

Energy Technology Data Exchange (ETDEWEB)

Shin, S. G.; Kim, S. K.; Kim, E. A. [Pohang University of Science and Technology, Pohang (Korea, Republic of)

2012-05-15

The PNF (Pohang Neutron Facility) electron Linac is providing converted neutrons and photons from electron beams to users for nuclear physics experiments and high energy gamma-ray exposures. This linac is capable of producing 100 MeV electron beams with a beam current of pulsed 100 mA. The pulse length is 2 {mu}s and the pulse repetition rate is typically 30 Hz. This linac consists of two SLAC-type S-band accelerating columns and the thermionic RF gun. They are powered by one klystron and the matching pulse modulator. The electron beams emitted from the RF gun are bunched as they pass through the alpha magnet and are injected into the accelerating column thereafter. In this paper, we discuss procedures and results of the beam transmission optimization with technical details of the accelerator system. We also briefly discuss the future upgrade plan to obtain short-pulse or electron beams for neutron TOF experiments by adopting a triode type thermionic DC electron gun

Nonclassical light sources for silicon photonics

Science.gov (United States)

Bajoni, Daniele; Galli, Matteo

2017-09-01

Quantum photonics has recently attracted a lot of attention for its disruptive potential in emerging technologies like quantum cryptography, quantum communication and quantum computing. Driven by the impressive development in nanofabrication technologies and nanoscale engineering, silicon photonics has rapidly become the platform of choice for on-chip integration of high performing photonic devices, now extending their functionalities towards quantum-based applications. Focusing on quantum Information Technology (qIT) as a key application area, we review recent progress in integrated silicon-based sources of nonclassical states of light. We assess the state of the art in this growing field and highlight the challenges that need to be overcome to make quantum photonics a reliable and widespread technology.

Photon spectrometry for the determination of the dose-rate constant of low-energy photon-emitting brachytherapy sources

International Nuclear Information System (INIS)

Chen, Zhe Jay; Nath, Ravinder

2007-01-01

Accurate determination of dose-rate constant (Λ) for interstitial brachytherapy sources emitting low-energy photons (<50 keV) has remained a challenge in radiation dosimetry because of the lack of a suitable absolute dosimeter for accurate measurement of the dose rates near these sources. Indeed, a consensus value of Λ taken as the arithmetic mean of the dose-rate constants determined by different research groups and dosimetry techniques has to be used at present for each source model in order to minimize the uncertainties associated with individual determinations of Λ. Because the dosimetric properties of a source are fundamentally determined by the characteristics of the photons emitted by the source, a new technique based on photon spectrometry was developed in this work for the determination of dose-rate constant. The photon spectrometry technique utilized a high-resolution gamma-ray spectrometer to measure source-specific photon characteristics emitted by the low-energy sources and determine their dose-rate constants based on the measured photon-energy spectra and known dose-deposition properties of mono-energetic photons in water. This technique eliminates many of the difficulties arising from detector size, the energy dependence of detector sensitivity, and the use of non-water-equivalent solid phantoms in absolute dose rate measurements. It also circumvents the uncertainties that might be associated with the source modeling in Monte Carlo simulation techniques. It was shown that the estimated overall uncertainty of the photon spectrometry technique was less than 4%, which is significantly smaller than the reported 8-10% uncertainty associated with the current thermo-luminescent dosimetry technique. In addition, the photon spectrometry technique was found to be stable and quick in Λ determination after initial setup and calibration. A dose-rate constant can be determined in less than two hours for each source. These features make it ideal to determine

Conformal intensity-modulated radiotherapy (IMRT) delivered by robotic linac-conformality versus efficiency of dose delivery

International Nuclear Information System (INIS)

Webb, Steve

2000-01-01

Intensity-modulated radiotherapy (IMRT) may be delivered with a high-energy-photon linac mounted on a robotic gantry and executing a complex trajectory. In a previous paper an inverse-planning technique was developed for such an application. Here the work is extended to demonstrate the dependence of conformality on the size of the elemental pencil beam, on the complexity of the trajectory and on the sampling of azimuth and elevation of the collimated source. The improved conformality of complex trajectories is demonstrated and benchmarked relative to simpler trajectories, more representative of existing non-robotic IMRT techniques. Specifically, by choosing a very fine pencil beam, exquisitely conformal dose distributions have been obtained. Important sampling considerations have been determined. Expressions have been derived for the dosimetry and monitor-unit efficiency of robotic IMRT. Equivalent trajectories were computed for executing the complex robotic trajectories instead by using a conventional linac. The work benchmarks an ideal in IMRT against which more practical and more common techniques may be measured. (author)

Characterizing multi-photon quantum interference with practical light sources and threshold single-photon detectors

Science.gov (United States)

Navarrete, Álvaro; Wang, Wenyuan; Xu, Feihu; Curty, Marcos

2018-04-01

The experimental characterization of multi-photon quantum interference effects in optical networks is essential in many applications of photonic quantum technologies, which include quantum computing and quantum communication as two prominent examples. However, such characterization often requires technologies which are beyond our current experimental capabilities, and today's methods suffer from errors due to the use of imperfect sources and photodetectors. In this paper, we introduce a simple experimental technique to characterize multi-photon quantum interference by means of practical laser sources and threshold single-photon detectors. Our technique is based on well-known methods in quantum cryptography which use decoy settings to tightly estimate the statistics provided by perfect devices. As an illustration of its practicality, we use this technique to obtain a tight estimation of both the generalized Hong‑Ou‑Mandel dip in a beamsplitter with six input photons and the three-photon coincidence probability at the output of a tritter.

Commissioning of the Superconducting Linac at the Spallation Neutron Source (SNS)

International Nuclear Information System (INIS)

Kim, Sang-Ho; Campisi, Isidoro E.

2007-01-01

The use of superconducting radiofrequency (SRF) cavities in particle accelerator is becoming more widespread. Among the projects that make use of that technology is the Spallation Neutron Source, where H-ions are accelerated to about 1 GeV, mostly making use of niobium elliptical cavities. SNS will use the accelerated short (about 700 ns) sub-bunches of protons to generate neutrons by spallation, which will in turn allow probing structural and magnetic properties of new and existing materials. The SNS superconducting linac is the largest application of RF superconductivity to come on-line in the last decade. The SRF cavities, operated at 805 MHz, were designed, built and integrated into cryomodules at Jefferson Lab and installed and tested at SNS. SNS is also the first proton-like accelerator which uses SRF cavities in a pulse mode. Many of the details of the cavity performance are peculiar to this mode of operation, which is also being applied to lepton accelerators (TESLA test facility and X-FEL at DESY and the international linear collider project). Thanks to the low frequency of the SNS superconducting cavities, operation at 4.2 K has been possible without beam energy degradation, even though the cavities and cryogenic systems were originally designed for 2.1 K operation. The testing of the superconducting cavities, the operating experience with beam and the performance of the superconducting linac will be presented

Analysis of phase velocity designing on superconducting section of proton Linac for spallation neutron source

International Nuclear Information System (INIS)

Ouyang Huafu; Xu Taoguang; Yu Qingchang; Guan Xialing; Luo Zihua

2001-01-01

A preliminary design of superconducting section of proton linac for spallation neutron source is made, which includes the design and optimization of the cavity shape and the architecture design of the superconducting section. In addition, the choice of the cell number of the superconducting cavity, the value of the geometric β G , the optimization principles of cavity and the beam dynamic properties are discussed

The TAC Radiation Source for Bremsstrahlung Application

International Nuclear Information System (INIS)

Demir, N.

2008-01-01

The TAC is a project for the first Turkish radiation source and currently design study is produced with funding from the DPT (State Planning Unity). Two main part of the project will be IR-FEL and Bremsstrahlung facility. Each LINAC will provide max. electron energy of 20 MeV. The Bremsstrahlung facility at TAC will consist two of the LINAC module and will be obtained 35 MeV photon energy. This would provide a chance to investigate nuclear structure at this energy range and also some application of photonuclear physics. In this work the main parameter and plans for those of facility will be detailed

Design and performance of the 40 MeV linac and beam transport system for the 1 GeV synchrotron radiation source at SORTEC

International Nuclear Information System (INIS)

Shiota, M.; Hiraki, A.; Mizota, M.; Iida, T.; Haraguchi, M.; Kuno, K.; Nakamura, S.; Ohno, M.; Tomimasu, T.

1990-01-01

A 1 Gev synchrotron radiation source (SOR) system has been installed and is now being adjusted at SORTEC corporation. This paper reports the configuration and the beam test results of the 40 MeV electron linac (pre-injector) and the beam transport line to the electron synchrotron used in this system. The output beam from the linac must be low emittance, small energy spread, and stable in energy. The beam transport line must also efficiently lead the beam from the linac to the electron synchrotron. This linac produced the beam current of 130 mA, with an energy spread of 1.3 % (FWHM), and an emittance of 0.7 πmm·mrad. The beam characteristics were verified by various beam monitors on the beam transport line. (author)

Radiation Protection Aspects of the Linac Coherent Light Source Front End Enclosure

Energy Technology Data Exchange (ETDEWEB)

Vollaire, J.; Fasso, A.; Liu, J.C.; Mao, X.S.; Prinz, A.; Rokni, S.H.; Leitner, M.Santana; /SLAC

2010-08-26

The Front End Enclosure (FEE) of the Linac Coherent Light Source (LCLS) is a shielding housing located between the electron dump area and the first experimental hutch. The upstream part of the FEE hosts the commissioning diagnostics for the FEL beam. In the downstream part of the FEE, two sets of grazing incidence mirror and several collimators are used to direct the beam to one of the experimental stations and reduce the bremsstrahlung background and the hard component of the spontaneous radiation spectrum. This paper addresses the beam loss assumptions and radiation sources entering the FEE used for the design of the FEE shielding using the Monte-Carlo code FLUKA. The beam containment system prevents abnormal levels of radiations inside the FEE and ensures that the beam remains in its intended path is also described.

Highly efficient photonic nanowire single-photon sources for quantum information applications

DEFF Research Database (Denmark)

Gregersen, Niels; Claudon, J.; Munsch, M.

2013-01-01

to a collection efficiency of only 1-2 %, and efficient light extraction thus poses a major challenge in SPS engineering. Initial efforts to improve the efficiency have exploited cavity quantum electrodynamics (cQED) to efficiently couple the emitted photons to the optical cavity mode. An alternative approach......Within the emerging field of optical quantum information processing, the current challenge is to construct the basic building blocks for the quantum computing and communication systems. A key component is the singlephoton source (SPS) capable of emitting single photons on demand. Ideally, the SPS...... must feature near-unity efficiency, where the efficiency is defined as the number of detected photons per trigger, the probability g(2)(τ=0) of multi-photon emission events should be 0 and the emitted photons are required to be indistinguishable. An optically or electrically triggered quantum light...

The Design of a Moderator for a Cold Neutron Source for the LINAC of the Centro Atomico Bariloche

International Nuclear Information System (INIS)

Torres, Lourdes; Gilette, Victor

2003-01-01

The results obtained in the design of a moderator to a cold neutron source for LINAC are given. Light water ice at 100 deg K was used as a moderator and we calculated its optimum dimension.We also calculated a grid moderator

Monte Carlo simulation of Varian Linac for 6 MV photon beam with BEAMnrc code

Science.gov (United States)

Mohammed, Maged; El Bardouni, T.; Chakir, E.; Boukhal, H.; Saeed, M.; Ahmed, Abdul-Aziz

2018-03-01

The purpose of this study is to investigate the effects of the initial electron beam parameters on the absorbed dose distribution calculated with EGSnrc Monte Carlo code, for 6 MV photon beam. A proposed methodology for benchmarking the BEAMnrc model of Varian Linac has been used. Also, a new photon cross section data based on ENDF/B-VII release 8 evaluation has been employed. The parameters tested include mean energy, radial intensity distribution and angular spread of the initial electron beam. Mean energy and angular spread were tested for a square irradiation field 10 × 10 cm2, whereas beam width of the electron beam was studied for 10 × 10 cm2 at different depths and 30 × 30 cm2 at depth of 10 cm. The results obtained are compared with measurement data to select the optimal electron beam parameters. The differences between MC calculation and measurements data are analyzed using gamma index criteria which fixed within 1% -1 mm accuracy. The obtained results indicated that the depth-dose and dose-profile curves were considerably influenced by the mean energy of the electron beam. The depth-dose curves were unaffected by the beam width of the electron beam, for both irradiation fields. On the contrary, lateral dose-profile curves were affected by the beam width of initial electron beam. Both dose-profile and depth-dose curves were unaffected to the angular spread of the electron beam. A deep depth of 10 × 10 cm2 is very accurate to tune the beam width. Mean energy and beam width must be tuned precisely, to get the MC does distribution with acceptable accuracy.

Control system for Siam photon source

CERN Document Server

Apiwatwaja, R; Isoyama, G; Ishii, T; Pairsuwan, W

2003-01-01

A new computer control system has been developed for Siam photon source, which is the first synchrotron light source in Thailand, personal computers and PLC's have been employed which are connected together through Ethernet. Man Machine Interface Stations (MMIS) at the front end act as a graphical user interface within Windows environment. The monitoring and controlling of individual devices is handled through several pairs of digital control station and the device interface located in each part of the synchrotron complex. The installation of the control system has been completed. The commissioning test of the control system is underway and the reliability of the system is on the positive side. Details of commissioning tests as well as characteristics of this newly built control system for the Siam photon source are described in this report.

Electron linacs

Energy Technology Data Exchange (ETDEWEB)

Loew, G A; Schriber, S O [ed.

1976-11-01

A study was made of the present status of the thousand or so electron linacs in the world, and future trends in the field. These machines were classified according to their use: medical, industrial, and nuclear physics. In the medical category, two types of electron linacs are discussed: the conventional ones which are used for x-ray and electron therapy, and those which may in the future be used for negative pion therapy. Industrial machines discussed include linacs for radiographic and other specialized applications. In the nuclear physics category, the status of conventional low- and medium-energy as well as high duty cycle linacs is reviewed. The question of how one might obtain a c-w, 1 GeV, 100..mu..A electron linac is raised, and various options using recirculation and stretchers are examined. In this connection, the status of rf superconductivity is summarized. A review is given of linacs for injectors into synchrotrons and e/sup +-/ storage rings, and recent work done to upgrade the only multi-GeV linac, namely SLAC, is described.

Electron linacs

International Nuclear Information System (INIS)

Loew, G.A.

1976-01-01

To study the present status of the thousand or so electron linacs in the world, and future trends in the field, we have classified these machines according to their use: medical, industrial, and nuclear physics. In the medical category, two types of electron linacs are discussed: the conventional ones which are used for X-ray and electron therapy, and those which may in the future be used for negative pion therapy. The section on industrial machines includes linacs for radiographic and other specialized applications. In the nuclear physics category, the status of conventional low- and medium-energy as well as high duty cycle linacs is reviewed. The question of how one might obtain a C.W., 1 GeV, 100 μA electron linac is raised and various options using recirculation and stretchers are examined. In this connection, the status of RF superconductivity is summarized. Following, there is a review of linacs for injectors into synchrotrons and e +- storage rings. The paper ends with a description of recent work done to upgrade the only multi-GeV linac, namely SLAC. (author)

Linac Coherent Light Source II (LCLS-II) Conceptual Design Report

International Nuclear Information System (INIS)

Stohr, J.

2011-01-01

The LCLS-II Project is designed to support the DOE Office of Science mission, as described in the 22 April 2010 Mission Need Statement. The scope of the Project was chosen to provide an increase in capabilities and capacity for the facility both at project completion in 2017 and in the subsequent decade. The Project is designed to address all points of the Mission Need Statement (MNS): (1) Expanded spectral reach; (2) Capability to provide x-ray beams with controllable polarization; (3) Capability to provide 'pump' pulses over a vastly extended range of photon energies to a sample, synchronized to LCLS-II x-ray probe pulses with controllable inter-pulse time delay; and (4) Increase of user access through parallel rather than serial x-ray beam use within the constraint of a $300M-$400M Total Project Cost (TPC) range. The LCLS-II Project will construct: (1) A hard x-ray undulator source (2-13 keV); (2) A soft x-ray undulator source (250-2,000 eV); (3) A dedicated, independent electron source for these new undulators, using sectors 10-20 of the SLAC linac; (4) Modifications to existing SLAC facilities for the injector and new shielded enclosures for the undulator sources, beam dumps and x-ray front ends; (5) A new experiment hall capable of accommodating four experiment stations; and (6) Relocation of the two soft x-ray instruments in the existing Near Experiment Hall (NEH) to the new experiment hall (Experiment Hall-II). A key objective of LCLS-II is to maintain near-term international leadership in the study of matter on the fundamental atomic length scale and the associated ultrafast time scales of atomic motion and electronic transformation. Clearly, such studies promise scientific breakthroughs in key areas of societal needs like energy, environment, health and technology, and they are uniquely enabled by forefront X-ray Free Electron Laser (X-FEL) facilities. While the implementation of LCLS-II extends to about 2017, it is important to realize that LCLS-II only

A compact rf driven H- ion source for linac injection

International Nuclear Information System (INIS)

Rymer, J.P.; Engeman, G.A.; Hamm, R.W.; Potter, J.M.

1991-01-01

A compact rf driven H - ion source has been developed for use as an injector for the AccSys radio frequency quadrupole (RFQ) linacs. A multicusp magnetic bucket geometry developed at Lawrence Berkeley Laboratory confines the plasma created by an antenna driven by 35 kW (peak) of pulsed rf power at 1.8 MHz. A three electrode system is used to extract and accelerate the H - beam, which is then focused into the RFQ by an einzel lens. Permanent magnets in the extraction region sweep electrons onto the second electrode at energies up to half of the full acceleration voltage. A fast pulsed valve allows the hydrogen gas supply to be pulsed, thus minimizing the average gas flow rate into the system. The design features and performance data from the prototype are discussed

Poster - 42: TB - ARC: A Total Body photon ARC technique using a commercially available linac

Energy Technology Data Exchange (ETDEWEB)

Evans, Michael D. C.; Ruo, Russell; Patrocinio, Horacio J.; Poon, Emily; Freeman, Carolyn; Hijal, Tarek; Parker, William [McGill University Health Centre (Canada)

2016-08-15

We have developed a total body photon irradiation technique using multiple overlapping open field arcs (TB-ARC). This simple technique uses predetermined arc-weights, with MUs calculated as a function of prescription depth only. Patients lie on a stretcher, in the prone/supine treatment position with AP/PA arcs. This treatment position has many advantages including ease of delivery (especially for tall, pediatric or compromised patients), dose uniformity, simplicity for organ shielding, and imaging capabilities. Using a Varian TrueBeam linac, 14 arcs using 40×40 cm{sup 2} 6 MV open photon beams, sweeping across 10 degrees each, complete a 140 degree arc. The nominal SSD at zero degrees is 200 cm. Arcs at the sweep limits (+/− 70 degrees) are differentially weighted and deliver a dose within 10% of the prescription on central axis, at a depth of 10 cm over a superior-inferior length of 275 cm. CT planning using Varian Eclipse enables dose evaluation. A custom made beam spoiler, consisting of a 2.5 m sheet of polycarbonate (6 mm thick) increases the surface dose from 45% to 90%. This beam spoiler also serves as a support in the event that differential attenuation is required for organs such as lung, heart, liver, kidneys. The geometry of the sweeping beam technique limits organ dose (using varying thicknesses of melting alloy) to about 20% and 40% of prescription at dmax and midplane respectively. Digital imaging with a portable DR cassette enables proper attenuator location prior to treatment.

Monte Carlo modeling of small photon fields: Quantifying the impact of focal spot size on source occlusion and output factors, and exploring miniphantom design for small-field measurements

International Nuclear Information System (INIS)

Scott, Alison J. D.; Nahum, Alan E.; Fenwick, John D.

2009-01-01

The accuracy with which Monte Carlo models of photon beams generated by linear accelerators (linacs) can describe small-field dose distributions depends on the modeled width of the electron beam profile incident on the linac target. It is known that the electron focal spot width affects penumbra and cross-field profiles; here, the authors explore the extent to which source occlusion reduces linac output for smaller fields and larger spot sizes. A BEAMnrc Monte Carlo linac model has been used to investigate the variation in penumbra widths and small-field output factors with electron spot size. A formalism is developed separating head scatter factors into source occlusion and flattening filter factors. Differences between head scatter factors defined in terms of in-air energy fluence, collision kerma, and terma are explored using Monte Carlo calculations. Estimates of changes in kerma-based source occlusion and flattening filter factors with field size and focal spot width are obtained by calculating doses deposited in a narrow 2 mm wide virtual ''milliphantom'' geometry. The impact of focal spot size on phantom scatter is also explored. Modeled electron spot sizes of 0.4-0.7 mm FWHM generate acceptable matches to measured penumbra widths. However the 0.5 cm field output factor is quite sensitive to electron spot width, the measured output only being matched by calculations for a 0.7 mm spot width. Because the spectra of the unscattered primary (Ψ Π ) and head-scattered (Ψ Σ ) photon energy fluences differ, miniphantom-based collision kerma measurements do not scale precisely with total in-air energy fluence Ψ=(Ψ Π +Ψ Σ ) but with (Ψ Π +1.2Ψ Σ ). For most field sizes, on-axis collision kerma is independent of the focal spot size; but for a 0.5 cm field size and 1.0 mm spot width, it is reduced by around 7% mostly due to source occlusion. The phantom scatter factor of the 0.5 cm field also shows some spot size dependence, decreasing by 6% (relative) as

Important aspects of linac beams for food irradiation

International Nuclear Information System (INIS)

McKeown, J.; Jones, R.T.

1987-01-01

Linac based irradiators will require careful design before they can be routinely adopted for the radiation processing of food. The transverse emittance and energy spread from simple injectors provide a significant challenge to the design of a beam delivery system which must handle high power especially in photon mode. Any nonuniform current distribution at the plane of the product is further complicated by large dose variations near the air/product interface, even with simple geometries. The paper describes the use of methods developed at AECL to control and monitor linac behaviour as well as electron interactions at the product surface. It also reports on activation cross-section measurements and particularly on neutron yields from composite targets, designed to monitor the energy of accelerators used in food applications. (orig.)

Experimental quantum teleportation and multiphoton entanglement via interfering narrowband photon sources

International Nuclear Information System (INIS)

Yang Jian; Zhang Han; Peng Chengzhi; Chen Zengbing; Bao Xiaohui; Chen Shuai; Pan Jianwei

2009-01-01

In this paper, we report a realization of synchronization-free quantum teleportation and narrowband three-photon entanglement through interfering narrowband photon sources. Since both the single-photon and the entangled photon pair utilized are completely autonomous, it removes the requirement of high-demanding synchronization techniques in long-distance quantum communication with pulsed spontaneous parametric down-conversion sources. The frequency linewidth of the three-photon entanglement realized is on the order of several MHz, which matches the requirement of atomic ensemble based quantum memories. Such a narrowband multiphoton source will have applications in some advanced quantum communication protocols and linear optical quantum computation.

Linac-beam characterizations at 600 MeV using optical transition radiation diagnostics.

Energy Technology Data Exchange (ETDEWEB)

Lumpkin, A. H.

1998-05-27

Selected optical diagnostics stations were upgraded in anticipation of low-emittance, bright electron beams from a thermionic rf gun or a photoelectric rf gun on the Advanced Photon Source (APS) injector linac. These upgrades include installation of optical transition radiation (OTR) screens, transport lines, and cameras for use in transverse beam size measurements and longitudinal profile measurements. Using beam from the standard thermionic gun, tests were done at 50 MeV and 400 to 650 MeV. Data were obtained on the limiting spatial ({sigma} {approximately} 200 {micro}m) and temporal resolution (300 ms) of the Chromox (Al{sub 2}O{sub 3} : Cr) screen (250-{micro}n thick) in comparison to the OTR screens. Both charge-coupled device (CCD) and charge-injection device (CID) video cameras were used as well as the Hamamatsu C5680 synchroscan streak camera operating at a vertical deflection rate of 119.0 MHz (the 24th subharmonic of the S-band 2856-MHz frequency). Beam transverse sizes as small as {sigma}{sub x} = 60 {micro}m for a 600-MeV beam and micropulse bunch lengths of {sigma}{sub {tau}}<3 ps have been recorded for macropulse-averaged behavior with charges of about 2 to 3 nC per macropulse. These techniques are applicable to linac-driven, fourth-generation light source R and D experiments including the APS's SASE FEL experiment.

Operational experience with the CERN hadron linacs

International Nuclear Information System (INIS)

Charmot, H.; Dutriat, C.; Hill, C.E.; Langbein, K.; Lombardi, A.M.; O'Neil, M.; Tanke, E.; Vretenar, M.

1996-01-01

The present CERN proton linac (Linac2) was commissioned in 1978 and since that date has been the primary source of protons to the CERN accelerator complex. During the past 18 years, the machine has had a very good reliability record in spite of the demands made upon it. Modifications have been made with the view of maintaining this reliability with reduced resources and new requirements from the users. Further demands will be made in the future for LHC operation. In 1994, a new linac for heavy ion production was put into service replacing the original CERN proton linac. As this machine was built within an international collaboration, operation had to take into account the novelty of the techniques used and the variety of equipment supplied by outside collaborators. Even so, the new machine has also had very good reliability. (author)

Recent Advances for High-Efficiency Sources of Single Photons Based on Photonic Nanowires

DEFF Research Database (Denmark)

Gerard, J. M.; Claudon, J.; Munsch, M.

2012-01-01

Photonic nanowires have recently been used to tailor the spontaneous emission of embedded quantum dots, and to develop record efficiency single-photon sources. We will present recent developments in this field mainly 1) the observation of a strong inhibition of the spontaneous emission of quantum...

Single Photon Sources in Silicon Carbide

International Nuclear Information System (INIS)

Brett Johnson

2014-01-01

Single photon sources in semiconductors are highly sought after as they constitute the building blocks of a diverse range of emerging technologies such as integrated quantum information processing, quantum metrology and quantum photonics. In this presentation, we show the first observation of single photon emission from deep level defects in silicon carbide (SiC). The single photon emission is photo-stable at room temperature and surprisingly bright. This represents an exciting alternative to diamond color centers since SiC possesses well-established growth and device engineering protocols. The defect is assigned to the carbon vacancy-antisite pair which gives rise to the AB photoluminescence lines. We discuss its photo-physical properties and their fabrication via electron irradiation. Preliminary measurements on 3C SiC nano-structures will also be discussed. (author)

A Silicon-Chip Source of Bright Photon-Pair Comb

Science.gov (United States)

2012-10-16

quantum light sources. Nature Photon. 1, 215 (2007). 14 Kwait, P. G., Mattle, K., Weinfurter, H., & Zeilinger , A. New High-Intensity Source of...Jennewein, T., & Zeilinger , A. A wavelength-tunable fiber-coupled 26 source of narrowband entangled photons. Opt. Express 15, 15377 (2007). 18 Chen...Lett. 101, 051108 (2012). 47 Ramelow, S., Ratschbacher, L., Fedrizzi, A., Langford, N. K., & Zeilinger , A. Discrete tunable color entanglement. Phys

Efficient fiber-coupled single-photon sources based on quantum dots

DEFF Research Database (Denmark)

Daveau, Raphaël Sura

refrigeration with coupled quantum wells. Many photonic quantum information processing applications would benet from a highbrightness, ber-coupled source of triggered single photons. This thesis presents a study of such sources based on quantum dots coupled to unidirectional photonic-crystal waveguide devices.......6 %. This latter method opens a promising future for increasing the eciency and reliability of planar chip-based single-photon sources. Refrigeration of a solid-state system with light has potential applications for cooling small-scale electronic and photonic circuits. We show theoretically that two coupled...... semiconductor quantum wells are ecient cooling media because they support long-lived indirect electron-hole pairs. These pairs can be thermally excited to distinct higher-energy states with faster radiative recombination, thereby creating an ecient escape channel to remove thermal energy from the system. From...

Michelson interferometer design for Linac Coherent Light Source (LCLS) applications in the 15-1.5 Aa wavelength range

International Nuclear Information System (INIS)

Tatchyn, Roman

2000-01-01

In recent years the continuing development of linac-driven X-Ray Free Electron Laser (XRFEL) designs has significantly expanded the parameter space associated with 3rd and earlier-generation synchrotron radiation sources. In particular, in contrast to the >100 ps pulse durations typical of storage rings, temporal lengths extending down to the <100 fs regime will become available. For example, for the SLAC Linac Coherent Light Source (LCLS) a pulse duration of ∼200-300 fs with finer temporal features extending down to ∼1 fs is anticipated. The characterization of the phase space distributions of such pulses poses a significant challenge for instrumentation design both with regard to the brevity of the pulse structure as well as the X-ray (15-1.5 Aa) wavelength range of the FEL line. In this paper we assess a Michelson interferometer design aimed at characterizing the coherence length of the SLAC LCLS and discuss considerations related to its operation

Preliminary Characterization of the O4+ Beam in Linac 3

CERN Document Server

Dumas, L; Scrivens, R; CERN. Geneva. AB Department

2007-01-01

The new GTS-LHC ECR ion source was installed in 2005. An oxygen 4+ beam was delivered to LEIR both for injection line (June 2005) and for the ring commissioning (September to December 2005). During these runs, studies were made of the beam transport in the Linac and towards LEIR. Some of the most significant results concerning the Linac are presented in this report. From 2006 the ECR source and the Linac3 delivered a lead beam for the LEIR commissioning, leaving some questions open for the oxygen beam transport. This report serves as a summary of the status of the investigations on the oxygen beam.

Three-color Sagnac source of polarization-entangled photon pairs.

Science.gov (United States)

Hentschel, Michael; Hübel, Hannes; Poppe, Andreas; Zeilinger, Anton

2009-12-07

We demonstrate a compact and stable source of polarization-entangled pairs of photons, one at 810 nm wavelength for high detection efficiency and the other at 1550 nm for long-distance fiber communication networks. Due to a novel Sagnac-based design of the interferometer no active stabilization is needed. Using only one 30 mm ppKTP bulk crystal the source produces photons with a spectral brightness of 1.13 x 10(6) pairs/s/mW/THz with an entanglement fidelity of 98.2%. Both photons are single-mode fiber coupled and ready to be used in quantum key distribution (QKD) or transmission of photonic quantum states over large distances.

Energy-Recovery Linacs for Commercial Radioisotope Production

International Nuclear Information System (INIS)

Johnson, Rolland Paul

2016-01-01

Most radioisotopes are produced by nuclear reactors or positive ion accelerators, which are expensive to construct and to operate. Photonuclear reactions using bremsstrahlung photon beams from less-expensive electron linacs can generate isotopes of critical interest, but much of the beam energy in a conventional electron linac is dumped at high energy, making unwanted radioactivation. The largest part of this radioactivation may be completely eliminated by applying energy recovery linac technology to the problem with an additional benefit that the energy cost to produce a given amount of isotope is reduced. Consequently, a Superconducting Radio Frequency (SRF) Energy Recovery Linac (ERL) is a path to a more diverse and reliable domestic supply of short-lived, high-value, high-demand isotopes at a cost lower than that of isotopes produced by reactors or positive-ion accelerators. A Jefferson Lab approach to this problem involves a thin photon production radiator, which allows the electron beam to recirculate through rf cavities so the beam energy can be recovered while the spent electrons are extracted and absorbed at a low enough energy to minimize unwanted radioactivation. The thicker isotope photoproduction target is not in the beam. MuPlus, with Jefferson Lab and Niowave, proposed to extend this ERL technology to the commercial world of radioisotope production. In Phase I we demonstrated that 1) the ERL advantage for producing radioisotopes is at high energies (~100 MeV), 2) the range of acceptable radiator thickness is narrow (too thin and there is no advantage relative to other methods and too thick means energy recovery is too difficult), 3) using optics techniques developed under an earlier STTR for collider low beta designs greatly improves the fraction of beam energy that can be recovered (patent pending), 4) many potentially useful radioisotopes can be made with this ERL technique that have never before been available in significant commercial quantities

Energy-Recovery Linacs for Commercial Radioisotope Production

Energy Technology Data Exchange (ETDEWEB)

Johnson, Rolland Paul [Muplus, Inc., Newport News, VA (United States)

2016-11-19

Most radioisotopes are produced by nuclear reactors or positive ion accelerators, which are expensive to construct and to operate. Photonuclear reactions using bremsstrahlung photon beams from less-expensive electron linacs can generate isotopes of critical interest, but much of the beam energy in a conventional electron linac is dumped at high energy, making unwanted radioactivation. The largest part of this radioactivation may be completely eliminated by applying energy recovery linac technology to the problem with an additional benefit that the energy cost to produce a given amount of isotope is reduced. Consequently, a Superconducting Radio Frequency (SRF) Energy Recovery Linac (ERL) is a path to a more diverse and reliable domestic supply of short-lived, high-value, high-demand isotopes at a cost lower than that of isotopes produced by reactors or positive-ion accelerators. A Jefferson Lab approach to this problem involves a thin photon production radiator, which allows the electron beam to recirculate through rf cavities so the beam energy can be recovered while the spent electrons are extracted and absorbed at a low enough energy to minimize unwanted radioactivation. The thicker isotope photoproduction target is not in the beam. MuPlus, with Jefferson Lab and Niowave, proposed to extend this ERL technology to the commercial world of radioisotope production. In Phase I we demonstrated that 1) the ERL advantage for producing radioisotopes is at high energies (~100 MeV), 2) the range of acceptable radiator thickness is narrow (too thin and there is no advantage relative to other methods and too thick means energy recovery is too difficult), 3) using optics techniques developed under an earlier STTR for collider low beta designs greatly improves the fraction of beam energy that can be recovered (patent pending), 4) many potentially useful radioisotopes can be made with this ERL technique that have never before been available in significant commercial quantities

Development of C{sup 6+} laser ion source and RFQ linac for carbon ion radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Sako, T., E-mail: takayuki1.sako@toshiba.co.jp; Yamaguchi, A.; Sato, K. [Toshiba Corporation, Yokohama 235-8522 (Japan); Goto, A.; Iwai, T.; Nayuki, T.; Nemoto, K.; Kayama, T. [Cancer Research Center, Yamagata University Faculty of Medicine, Yamagata 990-9585 (Japan); Takeuchi, T. [Accelerator Engineering Corporation, Chiba 263-0043 (Japan)

2016-02-15

A prototype C{sup 6+} injector using a laser ion source has been developed for a compact synchrotron dedicated to carbon ion radiotherapy. The injector consists of a laser ion source and a 4-vane radio-frequency quadrupole (RFQ) linac. Ion beams are extracted from plasma and directly injected into the RFQ. A solenoid guides the low-energy beams into the RFQ. The RFQ is designed to accelerate high-intensity pulsed beams. A structure of monolithic vanes and cavities is adopted to reduce its power consumption. In beam acceleration tests, a solenoidal magnetic field set between the laser ion source and the RFQ helped increase both the peak currents before and after the RFQ by a factor of 4.

Development of C⁶⁺ laser ion source and RFQ linac for carbon ion radiotherapy.

Science.gov (United States)

Sako, T; Yamaguchi, A; Sato, K; Goto, A; Iwai, T; Nayuki, T; Nemoto, K; Kayama, T; Takeuchi, T

2016-02-01

A prototype C(6+) injector using a laser ion source has been developed for a compact synchrotron dedicated to carbon ion radiotherapy. The injector consists of a laser ion source and a 4-vane radio-frequency quadrupole (RFQ) linac. Ion beams are extracted from plasma and directly injected into the RFQ. A solenoid guides the low-energy beams into the RFQ. The RFQ is designed to accelerate high-intensity pulsed beams. A structure of monolithic vanes and cavities is adopted to reduce its power consumption. In beam acceleration tests, a solenoidal magnetic field set between the laser ion source and the RFQ helped increase both the peak currents before and after the RFQ by a factor of 4.

Rf-synchronized imaging for particle and photon beam characterizations

Energy Technology Data Exchange (ETDEWEB)

Lumpkin, A.H.

1993-07-01

The usefulness of imaging electro-optics for rf-driven accelerators can be enhanced by synchronizing the instruments to the system fundamental frequency or an appropriate subharmonic. This step allows one to obtain micropulse bunch length and phase during a series of linac bunches or storage ring passes. Several examples now exist of the use of synchroscan and dual-sweep streak cameras and/or image dissector tubes to access micropulse scale phenomena (10 to 30 ps) during linac and storage ring operations in the US, Japan, and Europe. As space permits, selections will be presented from the list of phase stability phenomena on photoelectric injectors, micropulse length during a macropulse, micropulse elongation effects, transverse Wakefield effects within a micropulse, and submicropulse phenomena on a stored beam. Potential applications to the subsystems of the Advanced Photon Source (APS) will be briefly addressed.

A low-neutron background slow-positron source

International Nuclear Information System (INIS)

White, M. M.

1998-01-01

The addition of a thermionic rf gun [1] and a photocathode rf gun will allow the Advanced Photon Source (APS) linear accelerator (linac) [2] [3] to become a free-electron laser (FEL) driver [4]. As the FEL project progresses, the existing high-charge DC thermionic gun will no longer be critical to APS operation and could be used to generate high-energy or low-energy electrons to drive a slow-positron source. We investigated possibilities to create a useful low-energy source that could operate semi-independently and would have a low neutron background

H$^{-}$ ion source for CERN's Linac4 accelerator: simulation, experimental validation and optimization of the hydrogen plasma

CERN Document Server

Mattei, Stefano; Lettry, Jacques

2017-07-25

Linac4 is the new negative hydrogen ion (H$^-$) linear accelerator of the European Organization for Nuclear Research (CERN). Its ion source operates on the principle of Radio-Frequency Inductively Coupled Plasma (RF-ICP) and it is required to provide 50~mA of H$^-$ beam in pulses of 600~$\\mu$s with a repetition rate up to 2 Hz and within an RMS emittance of 0.25~$\\pi$~mm~mrad in order to fullfil the requirements of the accelerator. This thesis is dedicated to the characterization of the hydrogen plasma in the Linac4 H$^-$ ion source. We have developed a Particle-In-Cell Monte Carlo Collision (PIC-MCC) code to simulate the RF-ICP heating mechanism and performed measurements to benchmark the fraction of the simulation outputs that can be experimentally accessed. The code solves self-consistently the interaction between the electromagnetic field generated by the RF coil and the resulting plasma response, including a kinetic description of charged and neutral species. A fully-implicit implementation allowed to si...

Evaluation of the effects of different filters and helium bag on the reduction of electron contamination in photon beam of Neptune linac

International Nuclear Information System (INIS)

Bahreyni Toosi, M. T.; Saberi, H.; Momen Nejad, M.

2005-01-01

Skin sparing is one of the most desirable characteristics of high energy photon beams. However, the photons emerging from the target of linacs are contaminated by secondary electrons as a result of their interactions with air, collimators, flattening filter and any other objects in their path. This phenomenon tends to increase the skin dose received by the patients. A practical and simple way to reduce the contribution of electron contamination is to place a sheet of medium to high Z material just after the secondary collimator. In this study, filters having different thickness and atomic number were applied and their effectiveness on the reduction of skin dose was evaluated. Materials and Methods: The filters of different thickness and atomic number were applied. The percent depth dose values were determined by the direct measurements made in a Scanditronix water phantom using a PTW 31006 Pin Point chamber having a sensitive volume of 0.015 cm 3 . A Perspex filter holder was made to be installed on the accessory slot. A plastic bag containing helium was also made using thin plastic sheet to study the effect of the helium bag when it replaces the air column between the head of the linac and the phantom. All of the measurements were carried out for the three field sizes of 10*10, 20*20 and 25*25 cm 2 . The setups were adjusted for SSD 100 cm. The ratio of the surface dose to maximum dose (Ds) was used as the criterion to determine the optimum filter. Results: The dosimetry results obtained in the water phantom indicated that a 0.4 mm thick Pb filter is the most effective one. This filter reduces the Ds for the field sizes of 10*10, 20*20 and 25*25 cm 2 by 5.7, 7.9 and 9.6%, respectively. Also the simultaneous use of the optimum filter and He bag is more effective than the filter alone. It reduces the Ds by 6.3, 10.1 and 12.3% for the field sizes of 10*10,20*20 and 25*25 cm 2 , respectively. Discussion and Conclusion: Based on the results of this work it is evident

Conversion of the AGS linac to H- acceleration

International Nuclear Information System (INIS)

Witkover, R.L.; Barton, D.S.; Reece, R.K.

1983-01-01

The AGS 200 MeV linac was converted to an H - accelerator during the summer of 1982 using a magnetron-type source in the column of the second pre-injector pit. Because of the re-entrant electrode design, a 20 keV transport line was required to carry the beam to the first electrode. Several changes were made to the source which enhanced its performance over previous designs. The same H - beam current is available at 2.75 times the duty factor with reduced deterioration of its output over several months of operation. The source, 750 keV transport, and linac modifications and performance will be presented

The application of statistical process control in linac quality assurance

International Nuclear Information System (INIS)

Li Dingyu; Dai Jianrong

2009-01-01

Objective: To improving linac quality assurance (QA) program with statistical process control (SPC) method. Methods: SPC is applied to set the control limit of QA data, draw charts and differentiate the random and systematic errors. A SPC quality assurance software named QA M ANAGER has been developed by VB programming for clinical use. Two clinical cases are analyzed with SPC to study daily output QA of a 6MV photon beam. Results: In the clinical case, the SPC is able to identify the systematic errors. Conclusion: The SPC application may be assistant to detect systematic errors in linac quality assurance thus it alarms the abnormal trend to eliminate the systematic errors and improves quality control. (authors)

Tabulated square-shaped source model for linear accelerator electron beam simulation.

Science.gov (United States)

Khaledi, Navid; Aghamiri, Mahmood Reza; Aslian, Hossein; Ameri, Ahmad

2017-01-01

Using this source model, the Monte Carlo (MC) computation becomes much faster for electron beams. The aim of this study was to present a source model that makes linear accelerator (LINAC) electron beam geometry simulation less complex. In this study, a tabulated square-shaped source with transversal and axial distribution biasing and semi-Gaussian spectrum was investigated. A low energy photon spectrum was added to the semi-Gaussian beam to correct the bremsstrahlung X-ray contamination. After running the MC code multiple times and optimizing all spectrums for four electron energies in three different medical LINACs (Elekta, Siemens, and Varian), the characteristics of a beam passing through a 10 cm × 10 cm applicator were obtained. The percentage depth dose and dose profiles at two different depths were measured and simulated. The maximum difference between simulated and measured percentage of depth doses and dose profiles was 1.8% and 4%, respectively. The low energy electron and photon spectrum and the Gaussian spectrum peak energy and associated full width at half of maximum and transversal distribution weightings were obtained for each electron beam. The proposed method yielded a maximum computation time 702 times faster than a complete head simulation. Our study demonstrates that there was an excellent agreement between the results of our proposed model and measured data; furthermore, an optimum calculation speed was achieved because there was no need to define geometry and materials in the LINAC head.

High-efficiency single-photon source: The photonic wire geometry

DEFF Research Database (Denmark)

Claudon, J.; Bazin, Maela; Malik, Nitin S.

2009-01-01

We present a single-photon-source design based on the emission of a quantum dot embedded in a semiconductor (GaAs) nanowire. The nanowire ends are engineered (efficient metallic mirror and tip taper) to reach a predicted record-high collection efficiency of 90% with a realistic design. Preliminar...

Study of localized photon source in space of measures

International Nuclear Information System (INIS)

Lisi, M.

2010-01-01

In this paper we study a three-dimensional photon transport problem in an interstellar cloud, with a localized photon source inside. The problem is solved indirectly, by defining the adjoint of an operator acting on an appropriate space of continuous functions. By means of sun-adjoint semi groups theory of operators in a Banach space of regular Borel measures, we prove existence and uniqueness of the solution of the problem. A possible approach to identify the localization of the photon source is finally proposed.

RF Plasma modeling of the Linac4 H− ion source

CERN Document Server

Mattei, S; Hatayama, A; Lettry, J; Kawamura, Y; Yasumoto, M; Schmitzer, C

2013-01-01

This study focuses on the modelling of the ICP RF-plasma in the Linac4 H− ion source currently being constructed at CERN. A self-consistent model of the plasma dynamics with the RF electromagnetic field has been developed by a PIC-MCC method. In this paper, the model is applied to the analysis of a low density plasma discharge initiation, with particular interest on the effect of the external magnetic field on the plasma properties, such as wall loss, electron density and electron energy. The use of a multi-cusp magnetic field effectively limits the wall losses, particularly in the radial direction. Preliminary results however indicate that a reduced heating efficiency results in such a configuration. The effect is possibly due to trapping of electrons in the multi-cusp magnetic field, preventing their continuous acceleration in the azimuthal direction.

Applications of photon-in, photon-out spectroscopy with third-generation, synchrotron-radiation sources

International Nuclear Information System (INIS)

Lindle, D.W.; Perera, R.C.C.

1991-01-01

This report discusses the following topics: Mother nature's finest test probe; soft x-ray emission spectroscopy with high-brightness synchrotron radiation sources; anisotropy and polarization of x-ray emission from atoms and molecules; valence-hole fluorescence from molecular photoions as a probe of shape-resonance ionization: progress and prospects; structural biophysics on third-generation synchrotron sources; ultra-soft x-ray fluorescence-yield XAFS: an in situ photon-in, photon-out spectroscopy; and x-ray microprobe: an analytical tool for imaging elemental composition and microstructure

Effect of photon energy spectrum on dosimetric parameters of brachytherapy sources.

Science.gov (United States)

Ghorbani, Mahdi; Mehrpouyan, Mohammad; Davenport, David; Ahmadi Moghaddas, Toktam

2016-06-01

The aim of this study is to quantify the influence of the photon energy spectrum of brachytherapy sources on task group No. 43 (TG-43) dosimetric parameters. Different photon spectra are used for a specific radionuclide in Monte Carlo simulations of brachytherapy sources. MCNPX code was used to simulate 125I, 103Pd, 169Yb, and 192Ir brachytherapy sources. Air kerma strength per activity, dose rate constant, radial dose function, and two dimensional (2D) anisotropy functions were calculated and isodose curves were plotted for three different photon energy spectra. The references for photon energy spectra were: published papers, Lawrence Berkeley National Laboratory (LBNL), and National Nuclear Data Center (NNDC). The data calculated by these photon energy spectra were compared. Dose rate constant values showed a maximum difference of 24.07% for 103Pd source with different photon energy spectra. Radial dose function values based on different spectra were relatively the same. 2D anisotropy function values showed minor differences in most of distances and angles. There was not any detectable difference between the isodose contours. Dosimetric parameters obtained with different photon spectra were relatively the same, however it is suggested that more accurate and updated photon energy spectra be used in Monte Carlo simulations. This would allow for calculation of reliable dosimetric data for source modeling and calculation in brachytherapy treatment planning systems.

Entangling quantum-logic gate operated with an ultrabright semiconductor single-photon source.

Science.gov (United States)

Gazzano, O; Almeida, M P; Nowak, A K; Portalupi, S L; Lemaître, A; Sagnes, I; White, A G; Senellart, P

2013-06-21

We demonstrate the unambiguous entangling operation of a photonic quantum-logic gate driven by an ultrabright solid-state single-photon source. Indistinguishable single photons emitted by a single semiconductor quantum dot in a micropillar optical cavity are used as target and control qubits. For a source brightness of 0.56 photons per pulse, the measured truth table has an overlap with the ideal case of 68.4±0.5%, increasing to 73.0±1.6% for a source brightness of 0.17 photons per pulse. The gate is entangling: At a source brightness of 0.48, the Bell-state fidelity is above the entangling threshold of 50% and reaches 71.0±3.6% for a source brightness of 0.15.

Induction linacs

International Nuclear Information System (INIS)

Keefe, D.

1986-07-01

The principle of linear induction acceleration is described, and examples are given of practical configurations for induction linacs. These examples include the Advanced Technology Accelerator, Long Pulse Induction Linac, Radial Line Accelerator (RADLAC), and Magnetically-Insulated Electron-Focussed Ion Linac. A related concept, the auto accelerator, is described in which the high-current electron-beam technology in the sub-10 MeV region is exploited to produce electron beams at energies perhaps as high as the 100 to 1000 MeV range. Induction linacs for ions are also discussed. The efficiency of induction linear acceleration is analyzed

Guidelines for the calibration of low energy photon sources at beta-ray brachytherapy sources

International Nuclear Information System (INIS)

2000-01-01

With the development of improved methods of implanting brachytherapy sources in a precise manner for treating prostate cancer and other disease processes, there has been a tremendous growth in the use of low energy photon sources, such as 125 I and 103 Pd brachytherapy seeds. Low energy photon sources have the advantage of easier shielding and also lowering the dose to normal tissue. However, the dose distributions around these sources are affected by the details in construction of the source and its encapsulation more than other sources used for brachytherapy treatments, such as 192 Ir. With increasing number of new low energy photon sources on the market, care should be taken with regard to its traceability to primary standards. It cannot be assumed that a calibration factor for an ionization chamber that is valid for one type of low energy photon source, automatically is valid for another source even if both would use the same isotope. Moreover, the method used to calculate the dose must also take into account the structure of the source and the encapsulation. The dose calculation algorithm that is valid for one type of low energy source may not be valid for another source even if in both cases the same radionuclide is used. Simple ''point source'' approximations, i.e. where the source is modeled as a point, should be avoided, as such methods do not account for any details in the source construction. In this document, the dose calculation formalism adopted for low energy photon sources is that recommended by the American Association of Physicists in Medicine (AAPM) as outlined by Task Group-43 (TG-43). This method accounts for the source and capsule geometry. The AAPM recommends brachytherapy photon sources to be specified in terms of 'Air Kerma Strength' that is also used in the formalism mentioned above. On the other hand, the International Commission on Radiation Units and Measurements (ICRU) recommends that the specification be done in terms of Reference Air

Deterministic and Storable Single-Photon Source Based on a Quantum Memory

International Nuclear Information System (INIS)

Chen Shuai; Chen, Y.-A.; Strassel, Thorsten; Zhao Bo; Yuan Zhensheng; Pan Jianwei; Schmiedmayer, Joerg

2006-01-01

A single-photon source is realized with a cold atomic ensemble ( 87 Rb atoms). A single excitation, written in an atomic quantum memory by Raman scattering of a laser pulse, is retrieved deterministically as a single photon at a predetermined time. It is shown that the production rate of single photons can be enhanced considerably by a feedback circuit while the single-photon quality is conserved. Such a single-photon source is well suited for future large-scale realization of quantum communication and linear optical quantum computation

Finite Element Thermal Study of the Linac4 Plasma Generatora

CERN Document Server

Faircloth, D; Kuchler, D; Lettry, L; Scrivens, R; CERN. Geneva. BE Department

2010-01-01

The temperature distribution and heat flow at equilibrium of the plasma generator of the RF-powered non-cesiated Linac4 H- ion source have been studied with a finite element model. It is shown that the equilibrium temperatures obtained in the Linac4 nominal operation mode (100 kW RF power, 2 Hz, 0.4 ms pulse duration) are within material specifications except for the magnet cage, where a redesign may be necessary. To assess the upgrade of the Linac4 source for operation in the high-power operation mode of SPL, an extrapolation of the heat load towards 100 kW RF power, 50 Hz repetition rate and 0.4 ms pulse duration has been performed. The results indicate that a significant improvement of the source cooling is required to allow for operation in HP-SPL.

Single bunch transfer system for the National Synchrotron Light Source

International Nuclear Information System (INIS)

Sheehan, J.; Singh, O.; Rambo, W.

1983-01-01

The accelerator system at the National Synchrotron Light Source consists of an S-band 85 MeV linac and three synchrotron rings. The electron beam from the linac is accelerated by the booster ring to 600 MeV and transferred to one of the two storage rings. The smaller of the two rings operates between 300 and 800 MeV emtting photons in the vacuum ultraviolet (VUV), while the larger storage ring operates up to 2.5 GeV and emits photons in the x-ray spectrum. A system is described for loading the storage rings by filling a single-phase space bunch in the booster ring and transferring it at the end of each booster cycle into a selected bucket in one of the storage rings. By controlling the timing of the transfer on successive transfer cycles, many fill patterns may be obtained

A tunable, linac based, intense, broad-band THz source forpump-probe experiments

Energy Technology Data Exchange (ETDEWEB)

Schmerge, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Adolphsen, C. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Corbett, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Dolgashev, V. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Durr, H. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Fazio, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Fisher, A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Frisch, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Gaffney, K. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Guehr, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hastings, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hettel, B. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hoffmann, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hogan, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Holtkamp, N. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Huang, X. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Huang, Z. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Kirchmann, P. [SLAC National Accelerator Lab., Menlo Park, CA (United States); LaRue, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Limborg, C. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Lindenberg, A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Loos, H. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Maxwell, T. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Nilsson, A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Raubenheimer, T. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Reis, D. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Ross, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Shen, Z. -X. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stupakov, G. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Tantawi, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Tian, K. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Wu, Z. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Xiang, D. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Yakimenko, V. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

2015-02-02

We propose an intense THz source with tunable frequency and bandwidth that can directly interact with the degrees of freedom that determine the properties of materials and thus provides a new tool for controlling and directing these ultrafast processes as well as aiding synthesis of new materials with new functional properties. This THz source will broadly impact our understanding of dynamical processes in matter at the atomic-scale and in real time. Established optical pumping schemes using femtosecond visible frequency laser pulses for excitation are extended into the THz frequency regime thereby enabling resonant excitation of bonds in correlated solid state materials (phonon pumping), to drive low energy electronic excitations, to trigger surface chemistry reactions, and to all-optically bias a material with ultrashort electric fields or magnetic fields. A linac-based THz source can supply stand-alone experiments with peak intensities two orders of magnitude stronger than existing laser-based sources, but when coupled with atomic-scale sensitive femtosecond x-ray probes it opens a new frontier in ultrafast science with broad applications to correlated materials, interfacial and liquid phase chemistry, and materials in extreme conditions.

Linac Coherent Light Source II (LCLS-II) Conceptual Design Report

Energy Technology Data Exchange (ETDEWEB)

Stohr, J

2011-11-16

The LCLS-II Project is designed to support the DOE Office of Science mission, as described in the 22 April 2010 Mission Need Statement. The scope of the Project was chosen to provide an increase in capabilities and capacity for the facility both at project completion in 2017 and in the subsequent decade. The Project is designed to address all points of the Mission Need Statement (MNS): (1) Expanded spectral reach; (2) Capability to provide x-ray beams with controllable polarization; (3) Capability to provide 'pump' pulses over a vastly extended range of photon energies to a sample, synchronized to LCLS-II x-ray probe pulses with controllable inter-pulse time delay; and (4) Increase of user access through parallel rather than serial x-ray beam use within the constraint of a $300M-$400M Total Project Cost (TPC) range. The LCLS-II Project will construct: (1) A hard x-ray undulator source (2-13 keV); (2) A soft x-ray undulator source (250-2,000 eV); (3) A dedicated, independent electron source for these new undulators, using sectors 10-20 of the SLAC linac; (4) Modifications to existing SLAC facilities for the injector and new shielded enclosures for the undulator sources, beam dumps and x-ray front ends; (5) A new experiment hall capable of accommodating four experiment stations; and (6) Relocation of the two soft x-ray instruments in the existing Near Experiment Hall (NEH) to the new experiment hall (Experiment Hall-II). A key objective of LCLS-II is to maintain near-term international leadership in the study of matter on the fundamental atomic length scale and the associated ultrafast time scales of atomic motion and electronic transformation. Clearly, such studies promise scientific breakthroughs in key areas of societal needs like energy, environment, health and technology, and they are uniquely enabled by forefront X-ray Free Electron Laser (X-FEL) facilities. While the implementation of LCLS-II extends to about 2017, it is important to realize that

Preinjector for Linac 1, accelerating column

CERN Multimedia

1974-01-01

For a description of the Linac 1 preinjector, please see first 7403070X. High up on the wall of the Faraday cage (7403073X) is this drum-shaped container of the ion source (7403083X). It is mounted at the HV end of the accelerating column through which the ions (usually protons; many other types of ions in the course of its long history) proceed through the Faraday cage wall to the low-energy end (at ground potential) of Linac 1. The 520 kV accelerating voltage was supplied by a SAMES generator (7403074X).

Discussion of superconducting and room-temperature high-intensity ion linacs

International Nuclear Information System (INIS)

Jameson, R.A.

1996-01-01

The point of view taken in this discussion is that the basic technology base exists in all essential respects for both superconducting or room-temperature rf linac accelerators and associated power and control systems, and thus a project can make a choice between these technologies on overall system considerations. These include performance, cost, availability, flexibility, and upgradability. Large high-intensity neutron source proposals involving light-ion rf linacs in three categories are reviewed in this context. The categories arc cw linacs to high (∼1 GeV) and low (∼40 MeV) output energy, and pulsed linacs to energy ∼1 GeV

Low power rf system for the ALS Linac

International Nuclear Information System (INIS)

Lo, C.C.; Taylor, B.; Lancaster, H.

1991-05-01

The Linear Accelerator (Linac) in the Advanced Light Source (ALS) is designed to provide either single or multiple bunchers of 50 MeV electrons for the booster synchrotron. Three cavities are used in the Linac for electron bunching. The two subharmonic bunching cavities operate at 124.914 MHz and 499.654 MHz respectively. The S Band buncher operates at 2.997924 GHz. The low level RF system includes a master signal source, RF burst generators, signal phase control, timing trigger generators and a water temperature control system. The design and performance of the system will be described. 7 refs., 3 figs

Production of slow-positron beams with an electron linac

International Nuclear Information System (INIS)

Howell, R.H.; Alvarez, R.A.; Stanek, M.

1982-01-01

Intense, pulsed beams of low-energy positrons have been produced by a high-energy beam from an electron linac. The production efficiency for low-energy positrons has been determined for electrons with 60 to 120 MeV energy, low-energy positron beams from a linac can be of much higher intensity than those beams currently derived from radioactive sources

Operational experiences of the spallation neutron source superconducting linac and power ramp-up

International Nuclear Information System (INIS)

Kim, Sang-Ho

2009-01-01

The spallation neutron source (SNS) is a second generation pulsed neutron source and designed to provide a 1-GeV, 1.44-MW proton beam to a mercury target for neutron production. Since the commissioning of the accelerator complex in 2006, the SNS has started its operation for neutron production and beam power ramp-up has been in progress toward the design goal. All subsystems of the SNS were designed and developed for substantial improvements compared to existing accelerators because the design beam power is almost an order of magnitude higher compared to existing neutron facilities and the achievable neutron scattering performance will exceed present sources by more than a factor of 20 to 100. In this paper, the operational experiences with the SNS Superconducting Linac (SCL), Power Ramp-up Plan to reach the design goal and the Power Upgrade Plan (PUP) will be presented including machine, subsystem and beam related issues.

A magnetized Einzel lens electron dump for the Linac4 H− ion source

CERN Document Server

Midttun, O; Kronberger, M; Lettry, J; Pereira, H; Scrivens, R

2013-01-01

Linac4 is a 160 MeV linear accelerator which will inject negative hydrogen ions (H−) into CERN’s Proton Synchrotron Booster, a required upgrade to improve the beam brightness in the LHC injector chain. A volume production RF ion source, based on the design of the DESY RF source was implemented, but showed considerable electron dump ablation during operation at 45 keV beam energy. To reduce the electron beam power density in the dump, a magnetized Einzel lens is designed that reduces the beam energy to 10 keV before permanentmagnets dump the electrons on a tungsten surface. Presented in this paper are simulations of the design using IBSimu, the tunable range of parameters depending on the extracted H− and electron current, as well as details of the implementation, the choice of pulsed power converters and the electrode alignment system. In addition, simulations of proton extraction from this source will be shown.

Numerical simulations of stripping effects in high-intensity hydrogen ion linacs

Directory of Open Access Journals (Sweden)

J.-P. Carneiro

2009-04-01

Full Text Available Numerical simulations of H^{-} stripping losses from blackbody radiation, electromagnetic fields, and residual gas have been implemented into the beam dynamics code TRACK. Estimates of the stripping losses along two high-intensity H^{-} linacs are presented: the Spallation Neutron Source linac currently being operated at Oak Ridge National Laboratory and an 8 GeV superconducting linac currently being designed at Fermi National Accelerator Laboratory.

Aims of advanced photon science research

International Nuclear Information System (INIS)

Kimura, Toyoaki

2004-01-01

The Advanced Photon Research Center (APRC) of Japan Atomic Energy Research Institute is pursing the research and development of advanced photon sources such as a compact, ultra-short, high intensity laser, x-ray laser, and a superconducting linac-based free electron laser (FEL) and their applications. These compact and high-intensity lasers have various capabilities of producing radiations with distinguishing characteristics of ultra-short pulse, high coherence, etc. Hence, they can provide novel means of research in the field of nuclear energy applications and industrial and medical technologies. It is important for us to promote these researches on these high-intensity laser applications comprehensively and effectively under the collaborations with nationwide universities and industry. From this point of view it is expected that the APRC plays a role as a COE for these researches. Through these research activities for development of high-intensity lasers and their applications, we will develop ''photon science and technology'' as a leading key technology in the 21st century and contribute the development of science and technology including nuclear energy technology and production of new industries. (author)

Argonne tandem as injector to a superconducting linac

International Nuclear Information System (INIS)

Yntema, J.L.; Den Hartog, P.K.; Henning, W.; Kutschera, W.

1980-01-01

The Argonne Tandem uses Pelletron chains, NEC accelerator tubes, and a dual closed-corona system. Its main function is to be an injector for a superconducting linear accelerator. As long as the transverse and longitudinal emittances are within the acceptance of the linac, the output beam quality of the tandem-linac system is essentially determined by the tandem. The sensitivity of the linac to the longitudinal emittance ΔEΔt of the incident beam makes the output beam quality dependent on the negative-ion velocity distribution in the source, transit-time effects in the tandem, molecular-beam dissociation, and stripper-foil uniformity. This paper discusses these beam-degrading effects

Heavy ion induction linacs for fusion

International Nuclear Information System (INIS)

Bangerter, R.O.; Ho, D.D.M.

1991-01-01

In 1976 Denis Keefe proposed the heavy ion induction linac as a driver for inertial confinement fusion (ICF) power plants. Subsequent research has established that heavy ion fusion (HIF) is potentially an attractive energy source and has identified the issues that must be resolved to make HIF a reality. The principal accelerator issues are achieving adequately low transverse and longitudinal emittance and acceptable cost. Results from the single and multiple beam experiments at LBL on transverse emittance are encouraging. A predicted high current longitudinal instability that can affect longitudinal emittance is currently being studied. This paper presents an overview of economics and ICF target requirements and their relationship to accelerator design. It also presents a summary of the status of heavy ion induction linac research. It concludes with a discussion of research plans, including plans for the proposed Induction Linac Systems Experiments (ILSE)

Photon Factory activity report, 1988

International Nuclear Information System (INIS)

1989-01-01

Since the foundation of Photon Factory a decade age, it has played an important role as a unique synchrotron X-ray radiation source in Japan. Installation of various insertion devices, storage of intense positron beam and reduction of beam emittance were the substantial achievements in the last several years. The exploitation of the TRISTAN Accumulation Ring as a synchrotron radiation source has paved the way for a new potential of development. All these activities have brought about the increase of beamlines and the expansion of scientific fronts. Third International Conference on Synchrotron Radiation Instrumentation held in Tsukuba was one of the most highlighted events for the facility. In coming years, it is intended to open new research fields using the promising single bunch beam and circularly polarized wiggler radiation. The TRISTAN Main Ring also will be applied to synchrotron radiation research. The Photon Factory in a national synchrotron radiation research facility affiliated to the National Laboratory for High Energy Physics, and it consists of a 2.5 GeV electron linac, a 2.5 GeV storage ring as a synchrotron light source, beam lines and experimental stations. The operation, improvement and development in respective departments are reported. (Kako, I.)

Research and Development Toward a 4.5-1.5 Angstrom Linac Coherent Light Source (LCLS) at SLAC

International Nuclear Information System (INIS)

Tatchyn, R.; Arthur, J.; Baltay, M.

1995-08-01

In recent years significant studies have been initiated on the feasibility of utilizing a portion of the 3km S-band accelerator at SLAC to drive a short wavelength (4.5-1.5 A) Linac Coherent Light Source (LCLS), a Free Electron Laser (FEL) operating in the Self- Amplified Spontaneous Emission (SASE) regime. Electron beam requirements for single-pass saturation in a minimal time include: (1) a peak current in the 7 kA range, (2) a relative energy spread of <0.05%, and (3) a transverse emittance, ε[r-m], approximating the diffraction limit condition ε = λ / 4π, where lambda(m) is the output wavelength. Requirements on the insertion device include field error levels of 0.02% for keeping the electron bunch centered on and in phase with the amplified photons, and a focusing beta of 8 m/rad for inhibiting the dilution of its transverse density. Although much progress has been made in developing individual components and beam processing techniques necessary for LCLS operation down to approx. 20 A, a substantial amount of research and development is still required in a number of theoretical and experimental areas leading to the construction and operation of a 4.5-1.5 A LCLS. In this paper we report on a research and development program underway and in planning at SLAC for addressing critical questions in these areas

Sub-megahertz linewidth single photon source

Directory of Open Access Journals (Sweden)

Markus Rambach

2016-12-01

Full Text Available We report 100% duty cycle generation of sub-MHz single photon pairs at the rubidium D1 line using cavity-enhanced spontaneous parametric downconversion. The temporal intensity cross correlation function exhibits a bandwidth of 666±16 kHz for the single photons, an order of magnitude below the natural linewidth of the target transition. A half-wave plate inside our cavity helps to achieve triple resonance between pump, signal, and idler photon, reducing the bandwidth and simplifying the locking scheme. Additionally, stabilisation of the cavity to the pump frequency enables the 100% duty cycle. The quantum nature of the source is confirmed by the idler-triggered second-order autocorrelation function at τ=0 to be gs,s(2(0= 0.016±0.002 for a heralding rate of 5 kHz. The generated photons are well-suited for storage in quantum memory schemes with sub-natural linewidths, such as gradient echo memories.

Re-circulating linac vacuum system

International Nuclear Information System (INIS)

Wells, Russell P.; Corlett, John N.; Zholents, Alexander A.

2003-01-01

The vacuum system for a proposed 2.5 GeV, 10ΜA recirculating linac synchrotron light source [1] is readily achievable with conventional vacuum hardware and established fabrication processes. Some of the difficult technical challenges associated with synchrotron light source storage rings are sidestepped by the relatively low beam current and short beam lifetime requirements of a re-circulating linac. This minimal lifetime requirement leads directly to relatively high limits on the background gas pressure through much of the facility. The 10ΜA average beam current produces very little synchrotron radiation induced gas desorption and thus the need for an ante-chamber in the vacuum chamber is eliminated. In the arc bend magnets, and the insertion devices, the vacuum chamber dimensions can be selected to balance the coherent synchrotron radiation and resistive wall wakefield effects, while maintaining the modest limits on the gas pressure and minimal outgassing

A highly efficient single-photon source based on a quantum dot in a photonic nanowire

DEFF Research Database (Denmark)

Claudon, Julien; Bleuse, Joel; Malik, Nitin Singh

2010-01-01

–4 or a semiconductor quantum dot5–7. Achieving a high extraction efficiency has long been recognized as a major issue, and both classical solutions8 and cavity quantum electrodynamics effects have been applied1,9–12. We adopt a different approach, based on an InAs quantum dot embedded in a GaAs photonic nanowire......The development of efficient solid-state sources of single photons is a major challenge in the context of quantum communication,optical quantum information processing and metrology1. Such a source must enable the implementation of a stable, single-photon emitter, like a colour centre in diamond2...

MO-F-CAMPUS-T-04: Implementation of a Standardized Monthly Quality Check for Linac Output Management in a Large Multi-Site Clinic

Energy Technology Data Exchange (ETDEWEB)

Xu, H; Yi, B; Prado, K [Univ. of Maryland School Of Medicine, Baltimore, MD (United States)

2015-06-15

Purpose: This work is to investigate the feasibility of a standardized monthly quality check (QC) of LINAC output determination in a multi-site, multi-LINAC institution. The QC was developed to determine individual LINAC output using the same optimized measurement setup and a constant calibration factor for all machines across the institution. Methods: The QA data over 4 years of 7 Varian machines over four sites, were analyzed. The monthly output constancy checks were performed using a fixed source-to-chamber-distance (SCD), with no couch position adjustment throughout the measurement cycle for all the photon energies: 6 and 18MV, and electron energies: 6, 9, 12, 16 and 20 MeV. The constant monthly output calibration factor (Nconst) was determined by averaging the machines’ output data, acquired with the same monthly ion chamber. If a different monthly ion chamber was used, Nconst was then re-normalized to consider its different NDW,Co-60. Here, the possible changes of Nconst over 4 years have been tracked, and the precision of output results based on this standardized monthly QA program relative to the TG-51 calibration for each machine was calculated. Any outlier of the group was investigated. Results: The possible changes of Nconst varied between 0–0.9% over 4 years. The normalization of absorbed-dose-to-water calibration factors corrects for up to 3.3% variations of different monthly QA chambers. The LINAC output precision based on this standardized monthly QC relative to the TG-51 output calibration is within 1% for 6MV photon energy and 2% for 18MV and all the electron energies. A human error in one TG-51 report was found through a close scrutiny of outlier data. Conclusion: This standardized QC allows for a reasonably simplified, precise and robust monthly LINAC output constancy check, with the increased sensitivity needed to detect possible human errors and machine problems.

6 MeV RF Linac for cargo scanning and industrial radiography

International Nuclear Information System (INIS)

2017-01-01

RF Linac-based X-ray sources are very widely used for cargo-scanning and industrial X-ray radiography applications. A 6 MeV on-axis coupled-cavity S-band RF linac has been designed, developed and tested successfully at Electron Beam Centre, Navi Mumbai. This facility falls under the purview of BARC Safety Council, which has conducted safety reviews and awarded regulatory clearances for the operation of the linac system. This paper outlines the salient features of the 6 MeV linac, its safety aspects and test results. A brief history of regulatory aspects is also presented

Advanced Photon Source accelerator ultrahigh vacuum guide

International Nuclear Information System (INIS)

Liu, C.; Noonan, J.

1994-03-01

In this document the authors summarize the following: (1) an overview of basic concepts of ultrahigh vacuum needed for the APS project, (2) a description of vacuum design and calculations for major parts of APS, including linac, linac waveguide, low energy undulator test line, positron accumulator ring (PAR), booster synchrotron ring, storage ring, and insertion devices, and (3) cleaning procedures of ultrahigh vacuum (UHV) components presently used at APS

Single-photon sources for quantum technologies - Results of the joint research project SIQUTE

DEFF Research Database (Denmark)

Kück, S.; López, M.; Rodiek, B.

2017-01-01

In this presentation, the results of the joint research project “Single-Photon Sources for Quantum Technologies” (SIQUTE) [1] will be presented. The focus will be on the development of absolutely characterized single-photon sources, on the realization of an efficient waveguide-based single-photon......-photon source at the telecom wavelengths of 1.3 µm and 1.55 µm, on the implementation of the quantum-enhanced resolution in confocal fluorescence microscopy and on the development of a detector for very low photon fluxes...

Advanced Photon Source research: Volume 1, Number 1, April 1998

International Nuclear Information System (INIS)

1998-04-01

The following articles are included in this publication: (1) The Advanced Photon Source: A Brief Overview; (2) MAD Analysis of FHIT at the Structural Biology Center; (3) Advances in High-Energy-Resolution X-ray Scattering at Beamline 3-ID; (4) X-ray Imaging and Microspectroscopy of the Mycorrhyizal Fungus-Plant Symbiosis; (5) Measurement and Control of Particle-beam Trajectories in the Advanced Photon Storage Ring; (6) Beam Acceleration and Storage at the Advanced Photon Source; and (7) Experimental Facilities Operations and Current Status

MEIC Proton Beam Formation with a Low Energy Linac

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yuhong [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

2015-09-01

The MEIC proton and ion beams are generated, accumulated, accelerated and cooled in a new green-field ion injector complex designed specifically to support its high luminosity goal. This injector consists of sources, a linac and a small booster ring. In this paper we explore feasibility of a short ion linac that injects low-energy protons and ions into the booster ring.

Wakefields in SLAC linac collimators

Directory of Open Access Journals (Sweden)

A. Novokhatski

2014-12-01

Full Text Available When a beam travels near collimator jaws, it gets an energy loss and a transverse kick due to the backreaction of the beam field diffracted from the jaws. The effect becomes very important for an intense short bunch when a tight collimation of the background beam halo is required. In the Linac Coherent Light Source at SLAC a collimation system is used to protect the undulators from radiation due to particles in the beam halo. The halo is most likely formed from gun dark current or dark current in some of the accelerating sections. However, collimators are also responsible for the generation of wake fields. The wake field effect from the collimators not only brings an additional energy jitter and change in the trajectory of the beam, but it also rotates the beam on the phase plane, which consequently leads to a degradation of the performance of the Free Electron Laser at the Linac Coherent Light Source. In this paper, we describe a model of the wake field radiation in the SLAC linac collimators. We use the results of a numerical simulation to illustrate the model. Based on the model, we derive simple formulas for the bunch energy loss and the average kick. We also present results from experimental measurements that confirm our model.

Validation of a virtual source model of medical linac for Monte Carlo dose calculation using multi-threaded Geant4

Science.gov (United States)

Aboulbanine, Zakaria; El Khayati, Naïma

2018-04-01

The use of phase space in medical linear accelerator Monte Carlo (MC) simulations significantly improves the execution time and leads to results comparable to those obtained from full calculations. The classical representation of phase space stores directly the information of millions of particles, producing bulky files. This paper presents a virtual source model (VSM) based on a reconstruction algorithm, taking as input a compressed file of roughly 800 kb derived from phase space data freely available in the International Atomic Energy Agency (IAEA) database. This VSM includes two main components; primary and scattered particle sources, with a specific reconstruction method developed for each. Energy spectra and other relevant variables were extracted from IAEA phase space and stored in the input description data file for both sources. The VSM was validated for three photon beams: Elekta Precise 6 MV/10 MV and a Varian TrueBeam 6 MV. Extensive calculations in water and comparisons between dose distributions of the VSM and IAEA phase space were performed to estimate the VSM precision. The Geant4 MC toolkit in multi-threaded mode (Geant4-[mt]) was used for fast dose calculations and optimized memory use. Four field configurations were chosen for dose calculation validation to test field size and symmetry effects, , , and for squared fields, and for an asymmetric rectangular field. Good agreement in terms of formalism, for 3%/3 mm and 2%/3 mm criteria, for each evaluated radiation field and photon beam was obtained within a computation time of 60 h on a single WorkStation for a 3 mm voxel matrix. Analyzing the VSM’s precision in high dose gradient regions, using the distance to agreement concept (DTA), showed also satisfactory results. In all investigated cases, the mean DTA was less than 1 mm in build-up and penumbra regions. In regards to calculation efficiency, the event processing speed is six times faster using Geant4-[mt] compared to sequential

Conformal intensity-modulated radiotherapy (IMRT) delivered by robotic linac - testing IMRT to the limit?

International Nuclear Information System (INIS)

Webb, S.

1999-01-01

In this paper it is proposed that intensity-modulated radiotherapy (IMRT) could be delivered optimally by a short-length linac mounted on a robotic arm. The robot would allow the linac to 'plant' narrow pencils of photon radiation with any orientation (excluding zones within which the linac and couch might collide) relative to the planning target volume (PTV). The treatment is specified by the trajectory of the robot and by the number of monitor units (MUs) delivered at each robotic orientation. An inverse-planning method to determine the optimum robotic trajectory is presented. It is shown that for complex PTVs, specifically those with concavities in their outline, the conformality of the treatment is improved by the use of a complex trajectory in comparison with a less complex constrained trajectory and this improvement is quantified. It is concluded that robotic linac delivery would lead to a great flexibility in those IMRT treatments requiring very complicated dose distributions with complex 3D shapes. However, even using very fast computers, the goal of determining whether robotic linac delivery is the ultimate IMRT cannot be conclusively reached at present. (author)

Major projects for the use of high power linacs

International Nuclear Information System (INIS)

Prome, M.

1996-01-01

A review of the major projects for high power linacs is given. The field covers the projects aiming at the transmutation of nuclear waste or the production of tritium, as well as the production of neutrons for hybrid reactors or basic research with neutron sources. The technologies which arc common to all the projects are discussed. Comments are made on the technical difficulties encountered by all the projects, and the special problems of the pulsed linacs are mentioned. Elements for a comparison of normal conducting linacs versus superconducting ones are given. Finally the technical developments being made in various laboratories are reviewed. (author)

Quantum Communication with a High-Rate Entangled Photon Source

Science.gov (United States)

Wilson, Nathaniel C.; Chaffee, Dalton W.; Lekki, John D.; Wilson, Jeffrey D.

2016-01-01

A high generation rate photon-pair source using a dual element periodically-poled potassium titanyl phosphate (PP KTP) waveguide is described. The photon-pair source features a high pair generation rate, a compact power-efficient package, and continuous wave (CW) or pulsed operation. Characterization and test results are presented. Details and preliminary results of a laboratory free-space QKD experiment with the B92 protocol are also presented.

High energy photon reference for radiation protection: technical design of the LINAC beam and ionization chambers; and calculation of monoenergetic conversion coefficients

Directory of Open Access Journals (Sweden)

Dusciac D.

2016-01-01

Full Text Available In this work, we present the results of the first part of a research project aimed at offering a complete response to dosimeters providers and nuclear physicists’ demands for high-energy (6 – 9 MeV photon beams for radiation protection purposes. Classical facilities allowing the production of high-energy photonic radiation (proton accelerators, nuclear reactors are very rare and need large investment for development and use. A novel solution is proposed, consisting in the use of a medical linear accelerator, allowing a significant decrease of all costs.Using Monte Carlo simulations (MCNP5 and PENELOPE codes, a specifically designed electron-photon conversion target allowing for obtaining a high energy photon beam (with an average energy weighted by fluence of about 6 MeV has been built for radiation protection purposes. Due to the specific design of the target, this “realistic” radiation protection high-energy photon beam presents a uniform distribution of air kerma rate at a distance of 1 m, over a 30 × 30 cm2 surface. Two graphite cavity ionizing chambers for ionometric measurements have been built. For one of these chambers, the charge collection volume has been measured allowing for its use as a primary standard. The second ionizing chamber is used as a transfer standard; as such it has been calibrated in a 60Co beam, and in the high energy photon beam for radiation protection.The measurements with these ionizing chambers allowed for an evaluation of the air kerma rate in the LINAC based high-energy photon beam for radiation protection: the values cover a range between 36 mGy/h and 210 mGy/h, compatible with radiation protection purposes.Finally, using Monte Carlo simulations, conversion coefficients from air kerma to dose equivalent quantities have been calculated in the range between 10 keV and 22.4 MeV, for the spectral distribution of the fluence corresponding to the beam produced by the linear accelerator of the LNE-LNHB.

Cosmogenic photons strongly constrain UHECR source models

Directory of Open Access Journals (Sweden)

van Vliet Arjen

2017-01-01

Full Text Available With the newest version of our Monte Carlo code for ultra-high-energy cosmic ray (UHECR propagation, CRPropa 3, the flux of neutrinos and photons due to interactions of UHECRs with extragalactic background light can be predicted. Together with the recently updated data for the isotropic diffuse gamma-ray background (IGRB by Fermi LAT, it is now possible to severely constrain UHECR source models. The evolution of the UHECR sources especially plays an important role in the determination of the expected secondary photon spectrum. Pure proton UHECR models are already strongly constrained, primarily by the highest energy bins of Fermi LAT’s IGRB, as long as their number density is not strongly peaked at recent times.

The LBL [Lawrence Berkeley Laboratory] 1-2 GeV synchrotron radiation source

International Nuclear Information System (INIS)

Cornacchia, M.

1987-03-01

A description is presented of the conceptual design of the 1 to 2 GeV Synchrotron Radiation Source proposed for construction at Lawrence Berkeley Laboratory. This facility is designed to produce ultraviolet and soft x-ray radiation. The accelerator complex consists of an injection system (linac plus booster synchrotron) and a low-emittance storage ring optimized for insertion devices. Eleven straight sections are available for undulators and wigglers, and up to 48 photon beam lines may ultimately emanate from bending magnets. Design features of the radiation source are the high brightness of the photon beams, the very short pulses (tens of picoseconds), and the tunability of the radiation

On the e-linac-based neutron yield

International Nuclear Information System (INIS)

Bunatyan, G.G.; Nikolenko, V.G.; Popov, A.B.

2010-01-01

We treat neutron generating in high atomic number materials due to the photonuclear reactions induced by the Bremsstrahlung of an electron beam produced by linear electron accelerator (e-linac). The dependence of neutron yield on the electron energy and the irradiated sample size is considered for various sample materials. The calculations are performed without resort to the so-called 'numerical Monte Carlo simulation'. The acquired neutron yields are well correlated with the data asserted in investigations performed at a number of the e-linac-driven neutron sources

Femtosecond Laser--Pumped Source of Entangled Photons for Quantum Cryptography Applications

International Nuclear Information System (INIS)

Pan, D.; Donaldson, W.; Sobolewski, R.

2007-01-01

We present an experimental setup for generation of entangled-photon pairs via spontaneous parametric down-conversion, based on the femtosecond-pulsed laser. Our entangled-photon source utilizes a 76-MHz-repetition-rate, 100-fs-pulse-width, mode-locked, ultrafast femtosecond laser, which can produce, on average, more photon pairs than a cw laser of an equal pump power. The resulting entangled pairs are counted by a pair of high-quantum-efficiency, single-photon, silicon avalanche photodiodes. Our apparatus s intended as an efficient source/receiver system for the quantum communications and quantum cryptography applications

Status and plans for Linac4 installation and commissioning

CERN Document Server

Vretenar, M; Arnaudon, L; Baudrenghien, P; Bellodi, G; Broere, J; Brunner, O; Comblin, J F; Coupard, J; Dimov, V A; Fuchs, J F; Funken, A; Gerigk, F; Granemann Souza, E; Hanke, K; Hansen, J; Yarmohammadi Satri, M; Kozsar, I; Lallement, J B; Lenardon, F; Lettry, J; Lombardi, A M; Maglioni, C; Midtun, O; Mikulec, B; Nisbet, D; Paoluzzi, M; Raich, U; Ramberger, S; Roncarolo, F; Rossi, C; Sanchez Alvarez, J L; Scrivens, R; Tan, J; Valerio-Lizarraga, C A; Vollaire, J; Wegner, R; Weisz, S; Zocca, F

2014-01-01

Linac4 is a normal conducting 160 MeV Hˉ linear accelerator presently being installed and progressively commissioned at CERN. It will replace the ageing 50 MeV Linac2 as injector of the PS Booster (PSB), increasing at the same time its brightness by a factor of two thanks to the higher injection energy. This will be the first step of a program to increase the beam brightness in the LHC injectors for the needs of the High-Luminosity LHC project. After a series of beam measurements on a dedicated test stand the 3 MeV Linac4 front-end, including ion source, RFQ and a beam chopping line, has been recommissioned at its final position in the Linac4 tunnel. Commissioning of the following section, the Drift Tube Linac, is starting. Beam commissioning will take place in steps of increasing energy, to reach the final 160 MeV in 2015. An extended beam measurement phase including testing of stripping equipment for the PSB and a year-long test run to assess and improve Linac4 reliability will take place in 2016, prior to...

Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-03-01

Research results of hard photon technology have been summarized as a part of novel technology development highly utilizing the quantum nature of photon. Hard photon technology refers to photon beam technologies which use photon in the 0.1 to 200 nm wavelength region. Hard photon has not been used in industry due to the lack of suitable photon sources and optical devices. However, hard photon in this wavelength region is expected to bring about innovations in such areas as ultrafine processing and material synthesis due to its atom selective reaction, inner shell excitation reaction, and spatially high resolution. Then, technological themes and possibility have been surveyed. Although there are principle proposes and their verification of individual technologies for the technologies of hard photon generation, regulation and utilization, they are still far from the practical applications. For the photon source technology, the laser diode pumped driver laser technology, laser plasma photon source technology, synchrotron radiation photon source technology, and vacuum ultraviolet photon source technology are presented. For the optical device technology, the multi-layer film technology for beam mirrors and the non-spherical lens processing technology are introduced. Also are described the reduction lithography technology, hard photon excitation process, and methods of analysis and measurement. 430 refs., 165 figs., 23 tabs.

Characterization of the radiation environment at the UNLV accelerator facility during operation of the Varian M6 linac

Science.gov (United States)

Hodges, M.; Barzilov, A.; Chen, Y.; Lowe, D.

2016-10-01

The bremsstrahlung photon flux from the UNLV particle accelerator (Varian M6 model) was determined using MCNP5 code for 3 MeV and 6 MeV incident electrons. Human biological equivalent dose rates due to accelerator operation were evaluated using the photon flux with the flux-to-dose conversion factors. Dose rates were computed for the accelerator facility for M6 linac use under different operating conditions. The results showed that the use of collimators and linac internal shielding significantly reduced the dose rates throughout the facility. It was shown that the walls of the facility, in addition to the earthen berm enveloping the building, provide equivalent shielding to reduce dose rates outside to below the 2 mrem/h limit.

A Very Intense Neutrino Super Beam Experiment for Leptonic CP Violation Discovery based on the European Spallation Source Linac: A Snowmass 2013 White Paper

CERN Document Server

Baussan, E; Bogomilov, M.; Bouquerel, E.; Cederkäll, J.; Christiansen, P.; Coloma, P.; Cupial, P.; Danared, H.; Densham, C.; Dracos, M.; Ekelöf, T.; Eshraqi, M.; Fernandez Martinez, E.; Gaudiot, G.; Hall-Wilton, R.; Koutchouk, J.P.; Lindroos, M.; Matev, R.; McGinnis, D.; Mezzetto, M.; Miyamoto, R.; Mosca, L.; Ohlsson, T.; Öhman, H.; Osswald, F.; Peggs, S.; Poussot, P.; Ruber, R.; Tang, J.Y.; Tsenov, R.; Vankova-Kirilova, G.; Vassilopoulos, N.; Wildner, E.; Wurtz, J.

2014-01-01

Very intense neutrino beams and large neutrino detectors will be needed in order to enable the discovery of CP violation in the leptonic sector. We propose to use the proton linac of the European Spallation Source currently under construction in Lund, Sweden to deliver, in parallel with the spallation neutron production, a very intense, cost effective and high performance neutrino beam. The baseline program for the European Spallation Source linac is that it will be fully operational at 5 MW average power by 2022, producing 2 GeV 2.86 ms long proton pulses at a rate of 14 Hz. Our proposal is to upgrade the linac to 10 MW average power and 28 Hz, producing 14 pulses/s for neutron production and 14 pulses/s for neutrino production. Furthermore, because of the high current required in the pulsed neutrino horn, the length of the pulses used for neutrino production needs to be compressed to a few $\\mu$s with the aid of an accumulator ring. A long baseline experiment using this Super Beam and a megaton underground ...

High duty factor Plasma Generator for CERN’s Superconducting Proton Linac

CERN Document Server

Lettry, J; Scrivens, R; Chaudet, E; Faircloth, D; Favre, G; Geisser, JM; Kuchler, D; Mathot, S; Midttun, O; Paoluzzi, M; Schmitzer, C; Steyaert, D

2010-01-01

CERN’s Linac4 is a 160 MeV linear accelerator currently under construction. It will inject negatively charged hydrogen ions into CERN’s PS-Booster. Its ion source is a non-cesiated RF driven H- volume source directly inspired from the one of DESY and is aimed to deliver pulses of 80 mA of H- during 0.4 ms at a 2 Hz repetition rate. The Superconducting Proton Linac (SPL) project is part of the luminosity upgrade of the LHC, it consists of an extension of Linac4 up to 5 GeV and is foreseen to deliver protons to a future 50 GeV Synchrotron (PS2). For the SPL high power option (HP-SPL), the ion source would deliver pulses of 80 mA of H- during 1.2 ms and operate at a 50 Hz repetition rate. This significant upgrade motivates the design of the new water cooled plasma generator presented in this paper. Its engineering is based on the results of a finite element thermal study of the Linac4 H- plasma generator that identified critical components and thermal barriers. A cooling system is proposed which achieves the...

X-RAY ACTIVE MATRIX PIXEL SENSORS BASEDON J-FET TECHNOLOGY DEVELOPED FOR THE LINAC COHERENT LIGHT SOURCE.

Energy Technology Data Exchange (ETDEWEB)

CARINI,G.A.; CHEN, W.; LI, Z.; REHAK, P.; SIDDONS, D.P.

2007-10-29

An X-ray Active Matrix Pixel Sensor (XAMPS) is being developed for recording data for the X-ray Pump Probe experiment at the Linac Coherent Light Source (LCLS). Special attention has to be paid to some technological challenges that this design presents. New processes were developed and refined to address problems encountered during previous productions of XAMPS. The development of these critical steps and corresponding tests results are reported here.

LINAC5 - A Quasi-Alvarez Linac for BioLEIR

International Nuclear Information System (INIS)

Garland, J M; Lallement, J-B; Lombardi, A

2017-01-01

LINAC5 is a new linac proposed for the acceleration of light ions with Q/A = 1/3 to 1/4 for medical applications within the BioLEIR (Low Energy Ion Ring) design study at CERN. We propose a novel quasi-Alvarez drift-tube linac (DTL) accelerating structure design for LINAC5, which can reduce the length of a more conventional DTL structure, yet allows better beam focussing control and flexibility than the inter-digital H (IH) structures typically used for modern ion acceleration. We present the main sections of the linac with total length ∼12 m, including a 202 MHz radio frequency quadrupole (RFQ) a matching medium energy beam transport (MEBT) and a 405 MHz quasi-Alvarez accelerating section with an output energy of 4.2 MeV/u. Permanent magnet quadrupoles are proposed for use in the quasi-Alvarez structure to improve the compactness of the design and increase the efficiency. Lattice design considerations, multi-particle beam dynamics simulations and RFQ and radio frequency (RF) cavity designs are presented. (paper)

Characterization of the radiation environment at the UNLV accelerator facility during operation of the Varian M6 linac

International Nuclear Information System (INIS)

Hodges, M.; Barzilov, A.; Chen, Y.; Lowe, D.

2016-01-01

The bremsstrahlung photon flux from the UNLV particle accelerator (Varian M6 model) was determined using MCNP5 code for 3 MeV and 6 MeV incident electrons. Human biological equivalent dose rates due to accelerator operation were evaluated using the photon flux with the flux-to-dose conversion factors. Dose rates were computed for the accelerator facility for M6 linac use under different operating conditions. The results showed that the use of collimators and linac internal shielding significantly reduced the dose rates throughout the facility. It was shown that the walls of the facility, in addition to the earthen berm enveloping the building, provide equivalent shielding to reduce dose rates outside to below the 2 mrem/h limit. - Highlights: • A 3/6 MeV electron accelerator equipped with a high energy x-ray target was studied. • Monte Carlo modeling of photon flux was carried out for three accelerator configurations. • Human biological equivalent doses were evaluated within the accelerator facility building.

Measurements of Linac4 H$^{-}$ ion source beam with a magnetized Einzel lens electron dump

CERN Document Server

Midttun, O; Scrivens, R

2014-01-01

Linac4 is a part of the upgrade of CERN’s accelerator complex for increased luminosity in the LHC. A new system to extract the ion beam from the plasma generator has been designed and tested, in order to improve the reliability and beam optics of the pulsed H- ion source. This paper presents the successfully implemented extraction system and three different beam measurements. The simulations compare well to the measurements and show that the plasma density was too low for the extraction system design during the measurements.

The photonic nanowire: an emerging platform for highly efficient single-photon sources for quantum information applications

DEFF Research Database (Denmark)

Gregersen, Niels; Munsch, Mathieu; Malik, Nitin S.

2013-01-01

Efficient coupling between a localized quantum emitter and a well defined optical channel represents a powerful route to realize single-photon sources and spin-photon interfaces. The tailored fiber-like photonic nanowire embedding a single quantum dot has recently demonstrated an appealing...... potential. However, the device requires a delicate, sharp needle-like taper with performance sensitive to minute geometrical details. To overcome this limitation we demonstrate the photonic trumpet, exploiting an opposite tapering strategy. The trumpet features a strongly Gaussian far-field emission...

Superconducting linac

International Nuclear Information System (INIS)

Bollinger, L.M.; Shepard, K.W.; Wangler, T.P.

1978-01-01

This project has two goals: to design, build, and test a small superconducting linac to serve as an energy booster for heavy ions from an FN tandem electrostatic accelerator, and to investigate various aspects of superconducting rf technology. The main design features of the booster are described, a status report on various components (resonators, rf control system, linac control system, cryostats, buncher) is given, and plans for the near future are outlined. Investigations of superconducting-linac technology concern studies on materials and fabrication techniques, resonator diagnostic techniques, rf-phase control, beam dynamics computer programs, asymmetry in accelerating field, and surface-treatment techniques. The overall layout of the to-be-proposed ATLAS, the Argonne Tandem-Linac Accelerator System, is shown; the ATLAS would use superconducting technology to produce beams of 5 to 25 MeV/A. 6 figures

Operation of the tandem-linac accelerator

International Nuclear Information System (INIS)

Anon.

1985-01-01

The tandem-linac accelerator system is operated as a source of energetic heavy-ion projectiles for research in several areas of nuclear physics and occasionally in other areas of science. The accelerator system consists of a 9-MV tandem electrostatic accelerator and a superconducting-linac energy booster that can provide an additional 20 MV of acceleration. A figure shows the layout of this system, which will be operated in its present form until September 1985, when it will be incorporated into the larger ATLAS system. In both the present and future forms the accelerator is designed to provide the exceptional beam quality and overall versatility required for precision nuclear-structure research

SU-F-BRE-11: Neutron Measurements Around the Varian TrueBeam Linac

Energy Technology Data Exchange (ETDEWEB)

Maglieri, R; Seuntjens, J; Kildea, J [McGill University, Montreal, QC (Canada); Liang, L; DeBlois, F [Jewish General Hospital, Montreal, QC (Canada); Evans, M [Montreal General Hospital, Montreal, QC (Canada); Licea, A [Canadian Nuclear Safety Comission, Ottawa, Ontario (Canada); Dubeau, J; Witharana, S [Detec, Gatineau, QC (Canada)

2014-06-15

Purpose: With the emergence of flattening filter free (FFF) photon beams, several authors have noted many advantages to their use. One such advantage is the decrease in neutron production by photonuclear reactions in the linac head. In the present work we investigate the reduction in neutrons from a Varian TrueBeam linac using the Nested Neutron Spectrometer (NNS, Detec). The neutron spectrum, total fluence and source strength were measured and compared for 10 MV with and without flattening filter and the effect of moderation by the room and maze was studied for the 15 MV beam. Methods: The NNS, similar to traditional Bonner sphere detectors but operated in current mode, was used to measure the neutron fluence and spectrum. The NNS was validated for use in high dose rate environments using Monte Carlo simulations and calibrated at NIST and NRC Canada. Measurements were performed at several positions within the treatment room and maze with the linac jaws closed to maximize neutron production. Results: The measurements showed a total fluence reduction between 35-40% in the room and maze when the flattening filter was removed. The neutron source strength Qn was calculated from in-room fluence measurements and was found to be 0.042 × 10{sup 2} n/Gy, 0.026 × 10{sup 2} n/Gy and 0.59 × 101{sup 2} n/Gy for the 10 MV, the 10 MV FFF and 15 MV beams, respectively. We measured ambient equivalent doses of 11 mSv/hr, 7 mSv/hr and 218 mSv/hr for the 10 MV, 10 MV FFF and 15 MV by the head. Conclusion: Our measurements revealed a decrease in total fluence, neutron source strength and equivalent dose of approximately 35-40% across the treatment room for the FFF compared to FF modes. This demonstrates, as expected, that the flattening filter is a major component of the neutron production for the TrueBeam. The authors greatly acknowledge support form the Canadian Nuclear Commission and the Natural Sciences and Engineering Research Council of Canada through the CREATE program. Co

CERN Linac4 - The Space Charge Challenge Design and Commission

CERN Document Server

Hein, Lutz Matthias; Holzer, Bernhard

In the first phase of the upgrade program of the CERN accelerator complex the proton injector Linac2 will be replaced by a new, normal-conducting $H^-$ ion Linac, Linac4, allowing a significant increase of the proton flux intensity along the downstream accelerator complex. In the design of Linac4 three beam transport sections are implemented to match the beam between the different accelerator elements and to model the longitudinal pulse structure. These three beam transport sections, which are the most critical locations in terms of beam quality preservation, are in the focus of this thesis. During the work of this thesis the low energy beam transport (LEBT), which is required to match the source beam to the radiofrequency quadrupole (RFQ), has been commissioned and its beam dynamics re-constructed. The measurement campaign used to re-construct the LEBT beam dynamics was performed with the aim to prepare the RFQ commissioning and to maximise the LEBT performance. Downstream of the Linac4 accelerator the beam...

SU-E-T-270: Optimized Shielding Calculations for Medical Linear Accelerators (LINACs).

Science.gov (United States)

Muhammad, W; Lee, S; Hussain, A

2012-06-01

The purpose of radiation shielding is to reduce the effective equivalent dose from a medical linear accelerator (LINAC) to a point outside the room to a level determined by individual state/international regulations. The study was performed to design LINAC's room for newly planned radiotherapy centers. Optimized shielding calculations were performed for LINACs having maximum photon energy of 20 MV based on NCRP 151. The maximum permissible dose limits were kept 0.04 mSv/week and 0.002 mSv/week for controlled and uncontrolled areas respectively by following ALARA principle. The planned LINAC's room was compared to the already constructed (non-optimized) LINAC's room to evaluate the shielding costs and the other facilities those are directly related to the room design. In the evaluation process it was noted that the non-optimized room size (i.e., 610 × 610 cm 2 or 20 feet × 20 feet) is not suitable for total body irradiation (TBI) although the machine installed inside was having not only the facility of TBI but the license was acquired. By keeping this point in view, the optimized INAC's room size was kept 762 × 762 cm 2. Although, the area of the optimized rooms was greater than the non-planned room (i.e., 762 × 762 cm 2 instead of 610 × 610 cm 2), the shielding cost for the optimized LINAC's rooms was reduced by 15%. When optimized shielding calculations were re-performed for non-optimized shielding room (i.e., keeping room size, occupancy factors, workload etc. same), it was found that the shielding cost may be lower to 41 %. In conclusion, non- optimized LINAC's room can not only put extra financial burden on the hospital but also can cause of some serious issues related to providing health care facilities for patients. © 2012 American Association of Physicists in Medicine.

Source of single photons and interferometry with one photon. From the Young's slit experiment to the delayed choice

International Nuclear Information System (INIS)

Jacques, V.

2007-11-01

This manuscript is divided in two independent parts. In the first part, we study the wave-particle duality for a single photon emitted by the triggered photoluminescence of a single NV color center in a diamond nano-crystal. We first present the realization of a single-photon interference experiment using a Fresnel's bi-prism, in a scheme equivalent to the standard Young's double-slit textbook experiment. We then discuss the complementarity between interference and which-path information in this two-path interferometer. We finally describe the experimental realization of Wheeler's delayed-choice Gedanken experiment, which is a fascinating and subtle illustration of wave-particle duality. The second part of the manuscript is devoted to the efficiency improvement of single-photon sources. We first describe the implementation of a new single-photon source based on the photoluminescence of a single nickel-related defect center in diamond. The photophysical properties of such defect make this single-photon source well adapted to open-air quantum cryptography. We finally demonstrate an original method that leads to an improvement of single-molecule photo stability at room temperature. (author)

CAS CERN Accelerator School: Cyclotrons, linacs and their applications. Proceedings

International Nuclear Information System (INIS)

Turner, S.

1996-01-01

These proceedings present the lectures given at the eighth specialized course organized by the CERN Accelerator School (CAS), the topic this time being 'Cyclotrons, Linacs and Their Applications'. Following an introductory lecture on linacs, the fundamental features of electron, ion and induction linacs are described together with their RF systems and particle sources. Cyclotrons are then introduced followed by details of their different types, their magnet and RF design, and their injection and extraction systems, with a glance towards exotic and possible future machines. Chapters are then presented on the use of linacs and cyclotrons for medical, fission, fusion and material applications, as well as for isotope production. Finally, descriptions of the design of a radioisotope facility, the matching of accelerators to their task and the computational tools used in their design are included. (orig.)

CAS CERN Accelerator School: Cyclotrons, linacs and their applications. Proceedings

Energy Technology Data Exchange (ETDEWEB)

Turner, S [ed.

1996-03-04

These proceedings present the lectures given at the eighth specialized course organized by the CERN Accelerator School (CAS), the topic this time being `Cyclotrons, Linacs and Their Applications`. Following an introductory lecture on linacs, the fundamental features of electron, ion and induction linacs are described together with their RF systems and particle sources. Cyclotrons are then introduced followed by details of their different types, their magnet and RF design, and their injection and extraction systems, with a glance towards exotic and possible future machines. Chapters are then presented on the use of linacs and cyclotrons for medical, fission, fusion and material applications, as well as for isotope production. Finally, descriptions of the design of a radioisotope facility, the matching of accelerators to their task and the computational tools used in their design are included. (orig.).

SU-E-T-409: Evaluation of Tissue Composition Effect On Dose Distribution in Radiotherapy with 6 MV Photon Beam of a Medical Linac

Energy Technology Data Exchange (ETDEWEB)

Ghorbani, M; Tabatabaei, Z; Noghreiyan, A Vejdani [Mashhad University of Medical Sciences, Mashhad (Iran, Islamic Republic of); Meigooni, A Soleimani [Comprehensive Cancer Center of Nevada, Las Vegas, NV (United States)

2015-06-15

Purpose: The aim of this study is to evaluate soft tissue composition effect on dose distribution for various soft tissues and various depths in radiotherapy with 6 MV photon beam of a medical linac. Methods: A phantom and Siemens Primus linear accelerator were simulated using MCNPX Monte Carlo code. In a homogeneous cubic phantom, six types of soft tissue and three types of tissue-equivalent materials were defined separately. The soft tissues were muscle (skeletal), adipose tissue, blood (whole), breast tissue, soft tissue (9-component) and soft tissue (4-component). The tissue-equivalent materials included: water, A-150 tissue-equivalent plastic and perspex. Photon dose relative to dose in 9-component soft tissue at various depths on the beam’s central axis was determined for the 6 MV photon beam. The relative dose was also calculated and compared for various MCNPX tallies including,F8, F6 and,F4. Results: The results of the relative photon dose in various materials relative to dose in 9-component soft tissue and using different tallies are reported in the form of tabulated data. Minor differences between dose distributions in various soft tissues and tissue-equivalent materials were observed. The results from F6 and F4 were practically the same but different with,F8 tally. Conclusion: Based on the calculations performed, the differences in dose distributions in various soft tissues and tissue-equivalent materials are minor but they could be corrected in radiotherapy calculations to upgrade the accuracy of the dosimetric calculations.

Beam emittance of the Stony Brook Tandem-LINAC booster

International Nuclear Information System (INIS)

Scholldorf, A.H.

1984-01-01

This dissertation is primarily a study of the longitudinal and transverse beam emittance of the Stony Brook Heavy Ion Tandem LINAC Accelerator Facility, with a secondary emphasis on the beam dynamical design of two key elements of the system: a low energy double-drift buncher, and an achromatic double-90 0 LINAC injection system. A transverse emittance measuring system consisting of two translation stages controlled by stepper motors is described. Each stage carried a pair of beam defining slits mounted so that both horizontal and vertical emittances could be measured with only linear motion of the stage assembly. Beam currents were measured directly by a low-noise, high-sensitivity electrometer circuit integrated with the second slit-stage assembly. A mini-computer controlled the motors and acquired and displayed the data. Transverse emittance areas of beams of 12 C, 16 O, 32 S, and 58 Ni were measured at ion source extraction potential, after ion source acceleration, after tandem acceleration, and after LINAC acceleration. The results were analyzed in terms of source sputter-cone geometry, angle straggling in gas and foil strippers, and a variety of other factors

The advanced photon source

International Nuclear Information System (INIS)

Galayda, J.N.

1995-01-01

The Advanced Photon Source (APS) is a 7-GeV third-generation synchrotron radiation storage ring and full-energy positron injector. Construction project funding began in 1989, and ground breaking took place on 5 May 1990. Construction of all accelerator facilities was completed in January 1995 and storage ring commissioning is underway. First observation of x-rays from a bending magnet source took place on 26 March 1995. Nearly all performance specifications of the injector have been reached, and first observations indicate that the reliability, dynamic aperture, emittance, and orbit stability in the storage ring are satisfactory. Observation of radiation from the first of 20 insertion device beamlines is scheduled for October 1995. Start of regular operations is expected to take place well before the APS Project target date of December 1996

Integrated photon sources for quantum information science applications

Science.gov (United States)

Fanto, M. L.; Tison, C. C.; Steidle, J. A.; Lu, T.; Wang, Z.; Mogent, N. A.; Rizzo, A.; Thomas, P. M.; Preble, S. F.; Alsing, P. M.; Englund, D. R.

2017-10-01

Ring resonators are used as photon pair sources by taking advantage of the materials second or third order non- linearities through the processes of spontaneous parametric downconversion and spontaneous four wave mixing respectively. Two materials of interest for these applications are silicon for the infrared and aluminum nitride for the ultraviolet through the infrared. When fabricated into ring type sources they are capable of producing pairs of indistinguishable photons but typically suffer from an effective 50% loss. By slightly decoupling the input waveguide from the ring, the drop port coincidence ratio can be significantly increased with the trade-off being that the pump is less efficiently coupled into the ring. Ring resonators with this design have been demonstrated having coincidence ratios of 96% but requiring a factor of 10 increase in the pump power. Through the modification of the coupling design that relies on additional spectral dependence, it is possible to achieve similar coincidence ratios without the increased pumping requirement. This can be achieved by coupling the input waveguide to the ring multiple times, thus creating a Mach-Zehnder interferometer. This coupler design can be used on both sides of the ring resonator so that resonances supported by one of the couplers are suppressed by the other. This is the ideal configuration for a photon-pair source as it can only support the pump photons at the input side while only allowing the generated photons to leave through the output side. Recently, this device has been realized with preliminary results exhibiting the desired spectral dependence and with a coincidence ratio as high as 97% while allowing the pump to be nearly critically coupled to the ring. The demonstrated near unity coincidence ratio infers a near maximal heralding efficiency from the fabricated device. This device has the potential to greatly improve the scalability and performance of quantum computing and communication systems.

Construction and use of an intense positron source at new linac facilities in Germany. Conceptual report

International Nuclear Information System (INIS)

Brauer, G.

2000-07-01

In this conceptual report the idea to establish an European positron source for applied research (''EPOS'') based on new LINAC facilities in Germany (ELBE/Rossendorf or TTF-DESY/Hamburg) is considered. The report contains not only the outline of obvious applications in atomic physics, materials science and surface physics, but also several new methodical developments which are only possible with an intense positron beam. This opportunity will also allow the use and further development of imaging techniques being of special interest for industrial applications. (orig.)

Proton linacs for boron neutron capture therapy

International Nuclear Information System (INIS)

Lennox, A.J.

1993-08-01

Recent advances in the ability to deliver boron-containing drugs to brain tumors have generated interest in ∼4 MeV linacs as sources of epithermal neutrons for radiation therapy. In addition, fast neutron therapy facilities have been studying methods to moderate their beams to take advantage of the high cross section for epithermal neutrons on boron-10. This paper describes the technical issues involved in each approach and presents the motivation for undertaking such studies using the Fermilab linac. the problems which must be solved before therapy can begin are outlined. Status of preparatory work and results of preliminary measurements are presented

Design considerations for high-current superconducting ion linacs

International Nuclear Information System (INIS)

Delayen, J.R.; Bohn, C.L.; Micklich, B.J.; Roche, C.T.; Sagalovsky, L.

1993-01-01

Superconducting linacs may be a viable option for high-current applications such as fusion materials irradiation testing, spallation neutron source, transmutation of radioactive waste, tritium production, and energy production. These linacs must run reliably for many years and allow easy routine maintenance. Superconducting cavities operate efficiently with high cw gradients, properties which help to reduce operating and capital costs, respectively. However, cost-effectiveness is not the sole consideration in these applications. For example, beam impingement must be essentially eliminated to prevent unsafe radioactivation of the accelerating structures, and thus large apertures are needed through which to pass the beam. Because of their high efficiency, superconducting cavities can be designed with very large bore apertures, thereby reducing the effect of beam impingement. Key aspects of high-current cw superconducting linac designs are explored in this context

LFSC - Linac Feedback Simulation Code

Energy Technology Data Exchange (ETDEWEB)

Ivanov, Valentin; /Fermilab

2008-05-01

The computer program LFSC (<Linac Feedback Simulation Code>) is a numerical tool for simulation beam based feedback in high performance linacs. The code LFSC is based on the earlier version developed by a collective of authors at SLAC (L.Hendrickson, R. McEwen, T. Himel, H. Shoaee, S. Shah, P. Emma, P. Schultz) during 1990-2005. That code was successively used in simulation of SLC, TESLA, CLIC and NLC projects. It can simulate as pulse-to-pulse feedback on timescale corresponding to 5-100 Hz, as slower feedbacks, operating in the 0.1-1 Hz range in the Main Linac and Beam Delivery System. The code LFSC is running under Matlab for MS Windows operating system. It contains about 30,000 lines of source code in more than 260 subroutines. The code uses the LIAR ('Linear Accelerator Research code') for particle tracking under ground motion and technical noise perturbations. It uses the Guinea Pig code to simulate the luminosity performance. A set of input files includes the lattice description (XSIF format), and plane text files with numerical parameters, wake fields, ground motion data etc. The Matlab environment provides a flexible system for graphical output.

High duty factor plasma generator for CERN's Superconducting Proton Linac.

Science.gov (United States)

Lettry, J; Kronberger, M; Scrivens, R; Chaudet, E; Faircloth, D; Favre, G; Geisser, J-M; Küchler, D; Mathot, S; Midttun, O; Paoluzzi, M; Schmitzer, C; Steyaert, D

2010-02-01

CERN's Linac4 is a 160 MeV linear accelerator currently under construction. It will inject negatively charged hydrogen ions into CERN's PS-Booster. Its ion source is a noncesiated rf driven H(-) volume source directly inspired from the one of DESY and is aimed to deliver pulses of 80 mA of H(-) during 0.4 ms at a 2 Hz repetition rate. The Superconducting Proton Linac (SPL) project is part of the luminosity upgrade of the Large Hadron Collider. It consists of an extension of Linac4 up to 5 GeV and is foreseen to deliver protons to a future 50 GeV synchrotron (PS2). For the SPL high power option (HP-SPL), the ion source would deliver pulses of 80 mA of H(-) during 1.2 ms and operate at a 50 Hz repetition rate. This significant upgrade motivates the design of the new water cooled plasma generator presented in this paper. Its engineering is based on the results of a finite element thermal study of the Linac4 H(-) plasma generator that identified critical components and thermal barriers. A cooling system is proposed which achieves the required heat dissipation and maintains the original functionality. Materials with higher thermal conductivity are selected and, wherever possible, thermal barriers resulting from low pressure contacts are removed by brazing metals on insulators. The AlN plasma chamber cooling circuit is inspired from the approach chosen for the cesiated high duty factor rf H(-) source operating at SNS.

Beam dynamics and commissioning of low and medium energy H- beam at Linac4

CERN Document Server

Satri, Masoomeh Yarmohammadi; Lombardi, Alessandra; Lamehi-Rachti , Mohammad

The First step of the CERN Large Hadron Collider injectors upgrade (LIU) project is Linac4. It accelerates H- ions to 160 MeV in an 80 m long accelerator housed in a tunnel 12 m underground, presently under construction. It will replace the present 50 MeV proton Linac2 as injector of the proton accelerator complex to increase the LHC luminosity. It consists of a 45 keV RF volume source, a twosolenoid Low Energy Beam Transport (LEBT), a 352.2 MHz Radio Frequency Quadrupole (RFQ) accelerating the beam to 3 MeV, a Medium Energy Beam Transport (MEBT) line. The MEBT houses a fast chopper to selectively remove unwanted micro-bunches in the 352 MHz sequence and avoid losses at capture in the CERN PSB (1 MHz). After chopping, the beam acceleration continues by a 50 MeV Drift Tube Linac (DTL), a 100 MeV Cell-Coupled Drift Tube Linac and a Pi-Mode Structure bringing the beam to the final energy of 160 MeV. Linac4 has been commissioned with a temporary source up to 12 MeV. The beam commissioning stages of Linac4 in LEBT...

High-beta linac structures

International Nuclear Information System (INIS)

Schriber, S.O.

1979-01-01

Accelerating structures for high-beta linacs that have been and are in use are reviewed in terms of their performance. Particular emphasis is given to room-temperature structures and the disk-and-washer structure. The disk-and-washer structure has many attractive features that are discussed for pulsed high-gradient linacs, for 100% duty-cycle medium-gradient linacs and for high-current linacs requiring maximal amounts of stored energy in the electric fields available to the beam

Beam energy variability and other system considerations for a deuteron linac materials research neutron source

International Nuclear Information System (INIS)

Jameson, R.A.

1989-01-01

There are many overall system aspects and tradeoffs that must be considered in the design of a deuteron linac based neutron source for materials research, in order to obtain a facility with the best possible response to the user's needs, efficient and reliable operation and maintenance, at the optimum construction and operating cost. These considerations should be included in the facility design from the earliest conceptual stages, and rechecked at each stage to insure consistency and balance. Some of system requirements, particularly that of beam energy variability and its implications, are outlined in this talk. (author)

Plasma ignition and steady state simulations of the Linac4 H$^{-}$ ion source

CERN Document Server

Mattei, S; Yasumoto, M; Hatayama, A; Lettry, J; Grudiev, A

2014-01-01

The RF heating of the plasma in the Linac4 H- ion source has been simulated using an Particle-in-Cell Monte Carlo Collision method (PIC-MCC). This model is applied to investigate the plasma formation starting from an initial low electron density of 1012 m-3 and its stabilization at 1018 m-3. The plasma discharge at low electron density is driven by the capacitive coupling with the electric field generated by the antenna, and as the electron density increases the capacitive electric field is shielded by the plasma and induction drives the plasma heating process. Plasma properties such as e-/ion densities and energies, sheath formation and shielding effect are presented and provide insight to the plasma properties of the hydrogen plasma.

Spallation Neutron Source Drift Tube Linac Resonance Control Cooling System Modeling

CERN Document Server

Tang, Johnny Y; Champion, Marianne M; Feschenko, Alexander; Gibson, Paul; Kiselev, Yuri; Kovalishin, A S; Kravchuk, Leonid V; Kvasha, Adolf; Schubert, James P

2005-01-01

The Resonance Control Cooling System (RCCS) for the warm linac of the Spallation Neutron Source was designed by Los Alamos National Laboratory. The primary design focus was on water cooling of individual component contributions. The sizing the RCCS water skid was accomplished by means of a specially created SINDA/FLUINT model tailored to these system requirements. A new model was developed in Matlab Simulink and incorporates actual operational values and control valve interactions. Included is the dependence of RF input power on system operation, cavity detuning values during transients, time delays that result from water flows through the heat exchanger, the dynamic process of water warm-up in the cooling system due to dissipated RF power on the cavity surface, differing contributions on the cavity detuning due to drift tube and wall heating, and a dynamic model of the heat exchanger with characteristics in close agreement to the real unit. Because of the Matlab Simulink model, investigation of a wide range ...

Linac 1, inner structure

CERN Multimedia

1968-01-01

This photo shows the inner structure of Linac 1. As injector to the PS, and later to the Booster, Linac 1 accelerated protons to 50 MeV, but it has also accelerated heavier ions. Fitted with a 520 keV RFQ pre-injector (instead of the original Cockcroft-Walton generator), it delivered protons and heavy ions to LEAR, from 1982 to 1992. After 33 years of faithful service, Linac 1 was dismantled in 1992 to make room for Linac 3 (Pb ions).

High current induction linacs

International Nuclear Information System (INIS)

Barletta, W.; Faltens, A.; Henestroza, E.; Lee, E.

1994-07-01

Induction linacs are among the most powerful accelerators in existence. They have accelerated electron bunches of several kiloamperes, and are being investigated as drivers for heavy ion driven inertial confinement fusion (HIF), which requires peak beam currents of kiloamperes and average beam powers of some tens of megawatts. The requirement for waste transmutation with an 800 MeV proton or deuteron beam with an average current of 50 mA and an average power of 40 MW lies midway between the electron machines and the heavy ion machines in overall difficulty. Much of the technology and understanding of beam physics carries over from the previous machines to the new requirements. The induction linac allows use of a very large beam aperture, which may turn out to be crucial to reducing beam loss and machine activation from the beam halo. The major issues addressed here are transport of high intensity beams, availability of sources, efficiency of acceleration, and the state of the needed technology for the waste treatment application. Because of the transformer-like action of an induction core and the accompanying magnetizing current, induction linacs make the most economic sense and have the highest efficiencies with large beam currents. Based on present understanding of beam transport limits, induction core magnetizing current requirements, and pulse modulators, the efficiencies could be very high. The study of beam transport at high intensities has been the major activity of the HIF community. Beam transport and sources are limiting at low energies but are not significant constraints at the higher energies. As will be shown, the proton beams will be space-charge-dominated, for which the emittance has only a minor effect on the overall beam diameter but does determine the density falloff at the beam edge

LINAC4 - Views of the 3 MeV Front-end (H- Source, LEBT, RFQ, MEBT) with Test Bench.

CERN Multimedia

Anna Pantelia

2013-01-01

The Linac4 is the new linear accelerator that will replace Linac2 as proton low energy injector in the LHC accelerator chain. On 14 November, members of the Linac4 collaboration and the CERN Operation Group were brought together for their first “real day” in the Linac4 Control Room. Together, they successfully accelerated their first hydrogen ion beam to 3 MeV. It was an exciting moment for everyone involved marked the start of one of the most critical commissioning phases for the new accelerator.

Interference contrast in multi-source few photon optics

OpenAIRE

Laskowski, Wieslaw; Wiesniak, Marcin; Zukowski, Marek; Bourennane, Mohamed; Weinfurter, Harald

2009-01-01

Many recent experiments employ several parametric down conversion (PDC) sources to get multiphoton interference. Such interference has applications in quantum information. We study here how effects due to photon statistics, misalignment, and partial distinguishability of the PDC pairs originating from different sources may lower the interference contrast in the multiphoton experiments.

Temporal interference with frequency-controllable long photons from independent cold atomic sources

Science.gov (United States)

Qian, Peng; Gu, Zhenjie; Wen, Rong; Zhang, Weiping; Chen, J. F.

2018-01-01

The interference of single photons from independent sources is an essential tool in quantum information processing. However, the interfering of photons with long temporal states in a time-resolved manner has rarely been studied. This is because without transmitting spectral filters or coupling to a cavity mode single photons generated in traditional nonlinear crystals suffer from a short temporal profile below 1 ns. With spectral correlation maintained in the biphotons generated from spontaneous four-wave mixing process in cold atom clouds, here we demonstrate the temporal interference of two frequency-tunable long photons from two independent cold atomic sources. We observe and analyze the interference of frequency-mismatched photons, where the phenomenon of the quantum beat at megahertz separation is displayed. Our paper provides more details for the quantum beat of two independent narrow-band single photons, which may find potential application in frequency-encoded photonic qubits in quantum information processing.

Design of a cold-neutron source for the Bariloche LINAC with solid mesitylene as moderator material

International Nuclear Information System (INIS)

Torres, Lourdes; Granada, J.R.

2006-01-01

We present the results of calculations performed with the code MCNP-4C relative to the neutron-field behaviour within the moderator for the Bariloche-LINAC cold-neutron source, using mesitylene at 89 K as moderating material. Throughout the design calculations we used preliminary nuclear-data libraries for that material that were previously generated and partially validated. The optimum dimensions for a slab and a cylindrical moderator were obtained, with and without a premoderator, from the point of view of neutron production and time-width of the neutron pulse

Bright quantum dot single photon source based on a low Q defect cavity

DEFF Research Database (Denmark)

Maier, Sebastian; Gold, Peter; Forchel, A.

2014-01-01

The quasi-planar single photon source presented in this paper shows an extraction efficiency of 42% without complex photonic resonator geometries or lithography steps as well as a high purity with a g2(0) value of 0.023.......The quasi-planar single photon source presented in this paper shows an extraction efficiency of 42% without complex photonic resonator geometries or lithography steps as well as a high purity with a g2(0) value of 0.023....

Drift tubes of Linac 2

CERN Multimedia

CERN PhotoLab

1977-01-01

With the advent of the 800 MeV PS Booster in 1972, the original injector of the PS, a 50 MeV Alvarez-type proton linac, had reached its limits, in terms of intensity and stability. In 1973 one therefore decided to build a new linac (Linac 2), also with a drift-tube Alvarez structure and an energy of 50 MeV. It had a new Cockcroft-Walton preinjector with 750 keV, instead of the previous one with 500 keV. Linac 2 was put into service in 1980. The old Linac 1 was then used for the study of, and later operation with, various types of ions. This picture shows Linac 2 drift-tubes, suspended on stems coming from the top, in contrast to Linac 1, where the drift-tubes stood on stems coming from the bottom.

SU-E-T-506: Dosimetric Verification of Photon MLC Delivered Electron Fields for Implementing MERT On An Artiste Linac

International Nuclear Information System (INIS)

Jin, L; Eldib, A; Li, J; Wang, L; Ma, C; Fan, J

2014-01-01

Purpose: To verify the dose accuracy of photon MLC delivered electron fields for implementing energy-intensity modulated electron radiotherapy (MERT) on an Artiste linac. Methods: It was proposed to deliver MERT on an Artiste linac at a short SSD (60 cm) to reduce beam penumbra caused by electron scatters. An in-house developed Monte Carlo (MC)-based dose calculation/optimization planning code was used for treatment planning. Our previous study showed that the measured dose distribution of a breast plan showed good agreement with the calculations in low-medium dose regions while the differences in high dose regions were outstanding. A continuous work found that the discrepancy is mainly caused by improper modeling in MC for the single focused MLC in the Artiste which was simplified as double focused in the previous MC simulations. With this remodeled MLC in the calculations, an energy-intensity modulated electron plan using 6, 9, 12 and 15 MeV was generated for a breast treatment on a breast phantom at a 60 cm SSD and recalculated regarding a solid water phantom. For a test study, four of MLC segments (each with a different energy) generated in the plan were delivered to the phantom and a film measurement was performed at the depth of 2 cm. The measured 2D dose distribution was then compared with calculations. Results: For composite doses of the four segments, measured 2D dose distributions overall agree well with the calculations (3mm/3%) in most area. The separate measurement for a single MLC segment for each of energies also showed the consistence with the calculations. Conclusion: After remodeling MLC in the MC calculations, the measured dose distribution for a subset of MLC segments from a MERT plan showed good agreement. Further detailed verification for the full plan will be the work in the next step

Lattice Study for the Taiwan Photon Source

CERN Document Server

Kuo, Chin-Cheng; Chen Chien Te; Luo, Gwo-Huei; Tsai, Hung-Jen; Wang, Min-Huey

2005-01-01

The feasibility study for the new 3.0~3.3 GeV Taiwan synchrotron light source, dubbed Taiwan Photon Source, was initiated in July, 2004. The goal is to construct a high performance light source with extremely bright X-ray in complementary to the existing 1.5 GeV light source in Taiwan. The ring circumference is 518.4 m and a 24-cell DBA lattice structure is chosen. The natural emittance with distributed dispersion is less than 2 nm-rad. A large booster ring of 499.2 m sharing the storage ring tunnel will be adopted.

Radio frequency linear accelerators for NDT applications: Basic overview of RF linacs

International Nuclear Information System (INIS)

Hansen, H.J.

1998-01-01

High energy X-ray radiography can be an important part of a quality control program. In this article the author will present an overview of the technology found in a typical high energy X-ray source, the radio frequency (RF) linear accelerator. In NDT, linacs are used primarily for the inspection of thick sections of materials. Linacs are also used in applications such as high energy computed tomography of specimens greater than 1 m thick and cargo container inspection. Recent developments in reliable portable linacs are opening up other applications such as field inspection of pipelines, ships, bridges, and other civil infrastructure. The replacement of isotopes (such as Co-60) by the linac is an area for growth in the future. The shorter exposure times, improved image capabilities, and greatly reduced regulatory requirements of the linac make a persuasive argument for the replacement of isotopes with a portable linac. The linacs discussed here are those with X-ray energies from 1 to 20 MeV intended for use in NDT applications. The discussion will be in very broad terms; it will be impossible to discuss every variation in linac design. In addition, some topics have been necessarily simplified to increase the comprehensibility for a wider audience

CERN Linac4. The space charge challenge

Energy Technology Data Exchange (ETDEWEB)

Hein, Lutz Matthias

2013-08-06

In the first phase of the upgrade program of the CERN accelerator complex the proton injector Linac2 will be replaced by a new, normal-conducting H-ion Linac, Linac4, allowing a significant increase of the proton flux intensity along the downstream accelerator complex. In the design of Linac4 three beam transport sections are implemented to match the beam between the different accelerator elements and to model the longitudinal pulse structure. These three beam transport sections, which are the most critical locations in terms of beam quality preservation, are in the focus of this thesis. During the work of this thesis the Low Energy Beam Transport (LEBT), which is required to match the source beam to the radiofrequency quadrupole (RFQ), has been commissioned and its beam dynamics re-constructed. The measurement campaign used to reconstruct the LEBT beam dynamics was performed with the aim to prepare the RFQ commissioning and to maximise the LEBT performance. Downstream of the Linac4 accelerator the beam is transported along a 180 m long transfer line to the Proton Synchrotron Booster (PS-Booster). The transfer line optics was studied, optimised and sections were completely re-designed. The new transfer line optics is characterised by an improved preservation of the beam emittance, higher stability of the optical solution with respect to alignment errors and field jitters of the transfer line magnets and it is matched to each of the PS-Booster injection schemes. In a concluding ''Start-To-End'' simulation based on the measured beam characteristics at the LEBT exit the beam dynamics of the downstream Linac, including the transfer line, was calculated. To minimise particle losses within acceptable emittance preservation the beam optics of the Medium Energy Beam Transport (MEBT) was adapted to the measured beam parameters. This ''Start-To-End'' simulation was performed to identify critical sections of the Linac4 beam dynamics and

A Monte Carlo investigation of low-Z target image quality generated in a linear accelerator using Varian's VirtuaLinac

International Nuclear Information System (INIS)

Parsons, David; Robar, James L.; Sawkey, Daren

2014-01-01

Purpose: The focus of this work was the demonstration and validation of VirtuaLinac with clinical photon beams and to investigate the implementation of low-Z targets in a TrueBeam linear accelerator (Linac) using Monte Carlo modeling. Methods: VirtuaLinac, a cloud based web application utilizing Geant4 Monte Carlo code, was used to model the Linac treatment head components. Particles were propagated through the lower portion of the treatment head using BEAMnrc. Dose distributions and spectral distributions were calculated using DOSXYZnrc and BEAMdp, respectively. For validation, 6 MV flattened and flattening filter free (FFF) photon beams were generated and compared to measurement for square fields, 10 and 40 cm wide and at d max for diagonal profiles. Two low-Z targets were investigated: a 2.35 MeV carbon target and the proposed 2.50 MeV commercial imaging target for the TrueBeam platform. A 2.35 MeV carbon target was also simulated in a 2100EX Clinac using BEAMnrc. Contrast simulations were made by scoring the dose in the phosphor layer of an IDU20 aSi detector after propagating through a 4 or 20 cm thick phantom composed of water and ICRP bone. Results: Measured and modeled depth dose curves for 6 MV flattened and FFF beams agree within 1% for 98.3% of points at depths greater than 0.85 cm. Ninety three percent or greater of points analyzed for the diagonal profiles had a gamma value less than one for the criteria of 1.5 mm and 1.5%. The two low-Z target photon spectra produced in TrueBeam are harder than that from the carbon target in the Clinac. Percent dose at depth 10 cm is greater by 3.6% and 8.9%; the fraction of photons in the diagnostic energy range (25–150 keV) is lower by 10% and 28%; and contrasts are lower by factors of 1.1 and 1.4 (4 cm thick phantom) and 1.03 and 1.4 (20 cm thick phantom), for the TrueBeam 2.35 MV/carbon and commercial imaging beams, respectively. Conclusions: VirtuaLinac is a promising new tool for Monte Carlo modeling of novel

Compendium of Scientific Linacs

Energy Technology Data Exchange (ETDEWEB)

Clendenin, James E

2003-05-16

The International Committee supported the proposal of the Chairman of the XVIII International Linac Conference to issue a new Compendium of linear accelerators. The last one was published in 1976. The Local Organizing Committee of Linac96 decided to set up a sub-committee for this purpose. Contrary to the catalogues of the High Energy Accelerators which compile accelerators with energies above 1 GeV, we have not defined a specific limit in energy. Microtrons and cyclotrons are not in this compendium. Also data from thousands of medical and industrial linacs has not been collected. Therefore, only scientific linacs are listed in the present compendium. Each linac found in this research and involved in a physics context was considered. It could be used, for example, either as an injector for high energy accelerators, or in nuclear physics, materials physics, free electron lasers or synchrotron light machines. Linear accelerators are developed in three continents only: America, Asia, and Europe. This geographical distribution is kept as a basis. The compendium contains the parameters and status of scientific linacs. Most of these linacs are operational. However, many facilities under construction or design studies are also included. A special mention has been made at the end for the studies of future linear colliders.

Soft X-ray production by photon scattering in pulsating binary neutron star sources

International Nuclear Information System (INIS)

Bussard, R.W.; Meszaros, P.; Alexander, S.

1985-01-01

A new mechanism is proposed as a source of soft (less than 1 keV) radiation in binary pulsating X-ray sources, in the form of photon scattering which leaves the electron in an excited Landau level. In a plasma with parameters typical of such sources, the low-energy X-ray emissivity of this mechanism far exceeds that of bremsstrahlung. This copious source of soft photons is quite adequate to provide the seed photons needed to explain the power-law hard X-ray spectrum by inverse Comptonization on the hot electrons at the base of the accretion column. 13 references

Source of single photons and interferometry with one photon. From the Young's slit experiment to the delayed choice; Source de photons uniques et interferences a un seul photon. De l'experience des fentes d'Young au choix retarde

Energy Technology Data Exchange (ETDEWEB)

Jacques, V

2007-11-15

This manuscript is divided in two independent parts. In the first part, we study the wave-particle duality for a single photon emitted by the triggered photoluminescence of a single NV color center in a diamond nano-crystal. We first present the realization of a single-photon interference experiment using a Fresnel's bi-prism, in a scheme equivalent to the standard Young's double-slit textbook experiment. We then discuss the complementarity between interference and which-path information in this two-path interferometer. We finally describe the experimental realization of Wheeler's delayed-choice Gedanken experiment, which is a fascinating and subtle illustration of wave-particle duality. The second part of the manuscript is devoted to the efficiency improvement of single-photon sources. We first describe the implementation of a new single-photon source based on the photoluminescence of a single nickel-related defect center in diamond. The photophysical properties of such defect make this single-photon source well adapted to open-air quantum cryptography. We finally demonstrate an original method that leads to an improvement of single-molecule photo stability at room temperature. (author)

Linac4 RFQ assembly is carried out before installation in Building 152

CERN Multimedia

Anna Pantelia

2012-01-01

This series of pictures documents the assembly phase of the Linac4 RFQ (Radio Frequency Quadrupole), performed at the end of July 2012. The Linac4 RFQ is made of 3 modules, 1 meter each, assembled together to accelerate the H- or proton beam from the ion source extraction at 45 kV to the energy of 3 MeV. The RFQ is the first of the Linac4 accelerating structures, which will increase to 160 MeV the beam injection energy into the PS Booster as from the end of LS2.

SU-F-T-371: Development of a Linac Monte Carlo Model to Calculate Surface Dose

Energy Technology Data Exchange (ETDEWEB)

Prajapati, S; Yan, Y; Gifford, K [UT MD Anderson Cancer Center, Houston, TX (United States)

2016-06-15

Purpose: To generate and validate a linac Monte Carlo (MC) model for surface dose prediction. Methods: BEAMnrc V4-2.4.0 was used to model 6 and 18 MV photon beams for a commercially available linac. DOSXYZnrc V4-2.4.0 calculated 3D dose distributions in water. Percent depth dose (PDD) and beam profiles were extracted for comparison to measured data. Surface dose and at depths in the buildup region was measured with radiochromic film at 100 cm SSD for 4 × 4 cm{sup 2} and 10 × 10 cm{sup 2} collimator settings for open and MLC collimated fields. For the 6 MV beam, films were placed at depths ranging from 0.015 cm to 2 cm and for 18 MV, 0.015 cm to 3.5 cm in Solid Water™. Films were calibrated for both photon energies at their respective dmax. PDDs and profiles were extracted from the film and compared to the MC data. The MC model was adjusted to match measured PDD and profiles. Results: For the 6 MV beam, the mean error(ME) in PDD between film and MC for open fields was 1.9%, whereas it was 2.4% for MLC. For the 18 MV beam, the ME in PDD for open fields was 2% and was 3.5% for MLC. For the 6 MV beam, the average root mean square(RMS) deviation for the central 80% of the beam profile for open fields was 1.5%, whereas it was 1.6% for MLC. For the 18 MV beam, the maximum RMS for open fields was 3%, and was 3.1% for MLC. Conclusion: The MC model of a linac agreed to within 4% of film measurements for depths ranging from the surface to dmax. Therefore, the MC linac model can predict surface dose for clinical applications. Future work will focus on adjusting the linac MC model to reduce RMS error and improve accuracy.

Development of the High Energy Linac Systems

International Nuclear Information System (INIS)

Cho, Yong Sub; Kwon, Hyeok Jung; Kim, Han Sung; Chung, Byung Chul; Jang, Ji Ho; Gao, Changgi; Li, Yingmin; Sun, An; Tang, Yazhe; Zhang, Lipoing; Hwang, Yong Seok

2008-05-01

The main purpose of this project is studying the extension plan of the proton engineering frontier project (PEFP) 100-MeV Linac. It includes three categories. One is studying operation plan of the PEFP linac and its extended accelerators, and developing a distribution system of 100-MeV proton beams with a laser striping. Other is designing superconducting RF (SRF) modules and fabricating and testing a copper cavity model. The other is designing a rapid cycling synchrotron (RCS). The operation scheme of the PEFP linac is related to the optimization in the operation of the 100-MeV linac, 200-MeV SRF, and RCS. We studied several operational method to increase the validity of the accelerators. The beam distribution system has two roles. One is supplying proton beams of 100 MeV to the user group. The laser stripping of the negative hydrogen atoms is used in this case. The other beams are directed to the next high energy accelerators. This study contributes to increase the availability of the proton beams. The SRF is one of candidates to extend the PEFP linac system. Since the accelerating gradient of the SRF is much higher than the normal conducting accelerator, a lot of institutes over the world are developing the SRF structure. Main purposes are designing an SRF module, fabricating and testing an copper model which has similar material properties as Nb of the usual SRF cavity material. The RCS is a synchrotron whose injector is the PEFP 100-MeV linac. Main purposes are determining the lattice structure, studying the fast and slow extraction system, simulating beam behavior in the designed synchrotron. The RCS will be used as the spallation neutron source and tools in the basic and applied science including medical application

Production of Medical Isotopes with Electron Linacs

Energy Technology Data Exchange (ETDEWEB)

Rotsch, D A; Alford, K.; Bailey, J. L.; Bowers, D. L.; Brossard, T.; Brown, M. A.; Chemerisov, S. D.; Ehst, D.; Greene, J.; Gromov, R. G.; Grudzinski, J.J.; Hafenrichter, L.; Hebden, A. S.; Henning, W.; Heltemes, T. A.; Jerden, J.; Jonah, C. D.; Kalensky, M.; Krebs, J. F.; Makarashvili, V.; Micklich, B.; Nolen, J.; Quigley, K. J.; Schneider, J. F.; Smith, N. A.; Stepinski, D. C.; Sun, Z.; Tkac, P.; Vandegrift, G. F.; Virgo, M J; Wesolowski, K. A.; Youker, A. J.

2017-06-01

Radioisotopes play important roles in numerous areas ranging from medical treatments to national security and basic research. Radionuclide production technology for medical applications has been pursued since the early 1900s both commercially and in nuclear science centers. Many medical isotopes are now in routine production and are used in day-to-day medical procedures. Despite these advancements, research is accelerating around the world to improve the existing production methodologies as well as to develop novel radionuclides for new medical appli-cations. Electron linear accelerators (linacs) represent a unique method for the production of radioisotopes. Even though the basic technology has been around for decades, only recently have electron linacs capable of producing photons with sufficient energy and flux for radioisotope production become available. Housed in Argonne Nation-al Laboratory’s Low Energy Accelerator Facility (LEAF) is a newly upgraded 55 MeV/25-kW electron linear ac-celerator, capable of producing a wide range of radioiso-topes. This talk will focus on the work being performed for the production of the medical isotopes 99Mo (99Mo/99mTc generator), 67Cu, and 47Sc.

FEM design and simulation of a short, 10 MV, S-band Linac with Monte Carlo dose simulations

International Nuclear Information System (INIS)

Baillie, Devin; Aubin, J. St.; Steciw, S.; Fallone, B. G.

2015-01-01

Purpose: Current commercial 10 MV Linac waveguides are 1.5 m. The authors’ current 6 MV linear accelerator–magnetic resonance imager (Linac–MR) system fits in typical radiotherapy vaults. To allow 10 MV treatments with the Linac–MR and still fit within typical vaults, the authors design a 10 MV Linac with an accelerator waveguide of the same length (27.5 cm) as current 6 MV Linacs. Methods: The first design stage is to design a cavity such that a specific experimental measurement for breakdown is applicable to the cavity. This is accomplished through the use of finite element method (FEM) simulations to match published shunt impedance, Q factor, and ratio of peak to mean-axial electric field strength from an electric breakdown study. A full waveguide is then designed and tuned in FEM simulations based on this cavity design. Electron trajectories are computed through the resulting radio frequency fields, and the waveguide geometry is modified by shifting the first coupling cavity in order to optimize the electron beam properties until the energy spread and mean energy closely match values published for an emulated 10 MV Linac. Finally, Monte Carlo dose simulations are used to compare the resulting photon beam depth dose profile and penumbra with that produced by the emulated 10 MV Linac. Results: The shunt impedance, Q factor, and ratio of peak to mean-axial electric field strength are all matched to within 0.1%. A first coupling cavity shift of 1.45 mm produces an energy spectrum width of 0.347 MeV, very close to the published value for the emulated 10 MV of 0.315 MeV, and a mean energy of 10.53 MeV, nearly identical to the published 10.5 MeV for the emulated 10 MV Linac. The depth dose profile produced by their new Linac is within 1% of that produced by the emulated 10 MV spectrum for all depths greater than 1.5 cm. The penumbra produced is 11% narrower, as measured from 80% to 20% of the central axis dose. Conclusions: The authors have successfully

Linac4 45 keV Proton Beam Measurements

CERN Document Server

Bellodi, G; Hein, L M; Lallement, J-B; Lombardi, A M; Midttun, O; Scrivens, R; Posocco, P A

2013-01-01

Linac4 is a 160 MeV normal-conducting H- linear accelerator, which will replace the 50 MeV proton Linac2 as injector for the CERN proton complex. Commissioning of the low energy part - comprising the H - source, a 45 keV Low Energy Beam Transport line (LEBT), a 3 MeV Radiofrequency Quadrupole (RFQ) and a Medium Energy Beam Transport (MEBT) - will start in fall 2012 on a dedicated test stand installation. In preparation to this, preliminary measurements were taken using a 45 keV proton source and a temporary LEBT setup, with the aim of characterising the output beam by comparison with the predictions of simulations. At the same time this allowed a first verification of the functionalities of diagnostics instrumentation and acquisition software tools. Measurements of beam profile, emittance and intensity were taken in three different setups: right after the source, after the first and after the second LEBT solenoids respectively. Particle distributions were reconstructed from emittance scan...

Conceptual designs of beam choppers for RFQ linacs

International Nuclear Information System (INIS)

Nath, S.; Stevens, S.R. Jr.; Wangler, T.P.

1995-01-01

A design study at Los Alamos of a linac/accumulator ring facility for a pulsed neutron spallation source calls for an H - beam with a chopped structure of approximately 200-ns beam-free segments every 600-ns. The required angular impulse can easily be provided with existing pulse power technology and traveling wave structures with a transverse electric field similar to those now available. The deflected beam is then restored by suitable collimation. Chopping is relatively easily done at sufficiently low energies, where the beam is easily deflected, and beam powers are not too large. However, the energy should be high enough so that the space-charge blow-up of the beam can be controlled with adequate focusing. LAMPF presently uses a traveling-wave beam chopper at 750 keV, before injection into the drift tube linac (DTL). In the new linac designs, a radiofrequency quadrupole (RFQ) linac would typically bunch and accelerate the high intensity H - beam from 100 keV to 7 MeV. In this paper, the authors present concepts for beam-chopper systems both before and after the RFQ. The beam-optics designs are presented, together with numerical simulation results

SRF LINAC for future extension of the PEFP

Energy Technology Data Exchange (ETDEWEB)

Kim, Han Sung; Kwon, Hyeok Jung; Seol, Kyoung Tae; Jang, Ji Ho; Cho, Yong Sub [Proton Engineering Frontier Project, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-04-15

A study on the superconducting RF linac is underway in order to increase the beam energy up to 1 GeV by extending the Proton Engineering Frontier Project (PEFP) 100-MeV linac. The operating frequency of the PEFP superconducting linac (SCL) is 700 MHz, which is determined by the fact that the frequency of the existing normal conducting linac is 350 MHz. A preliminary study on the beam dynamics showed that two types of cavities with geometrical betas of 0.50 and 0.74 could cover the entire energy range from 100 MeV to 1 GeV. An inductive output tube (IOT) based RF system is under consideration as a high-power RF source for the SCL due to its low operating voltage and high efficiency. As a prototyping activity for a reduced beta cavity, a five-cell cavity with a geometrical beta of 0.42 was designed and fabricated. A vertical test of the prototype cavity at low temperatures was performed to check the performance of the cavity. The design study and the prototyping activity for the PEFP SCL will be presented in this paper.

SRF LINAC for future extension of the PEFP

International Nuclear Information System (INIS)

Kim, Han Sung; Kwon, Hyeok Jung; Seol, Kyoung Tae; Jang, Ji Ho; Cho, Yong Sub

2014-01-01

A study on the superconducting RF linac is underway in order to increase the beam energy up to 1 GeV by extending the Proton Engineering Frontier Project (PEFP) 100-MeV linac. The operating frequency of the PEFP superconducting linac (SCL) is 700 MHz, which is determined by the fact that the frequency of the existing normal conducting linac is 350 MHz. A preliminary study on the beam dynamics showed that two types of cavities with geometrical betas of 0.50 and 0.74 could cover the entire energy range from 100 MeV to 1 GeV. An inductive output tube (IOT) based RF system is under consideration as a high-power RF source for the SCL due to its low operating voltage and high efficiency. As a prototyping activity for a reduced beta cavity, a five-cell cavity with a geometrical beta of 0.42 was designed and fabricated. A vertical test of the prototype cavity at low temperatures was performed to check the performance of the cavity. The design study and the prototyping activity for the PEFP SCL will be presented in this paper.

SU-E-T-272: Direct Verification of a Treatment Planning System Megavoltage Linac Beam Photon Spectra Models, and Analysis of the Effects On Patient Plans

Energy Technology Data Exchange (ETDEWEB)

Leheta, D; Shvydka, D; Parsai, E [University of Toledo Medical Center, Toledo, OH (United States)

2015-06-15

Purpose: For the photon dose calculation Philips Pinnacle Treatment Planning System (TPS) uses collapsed cone convolution algorithm, which relies on energy spectrum of the beam in computing the scatter component. The spectrum is modeled based on Linac’s standard commissioning data and typically is not independently verified. We explored a methodology of using transmission measurements in combination with regularization data processing to unfold Linac spectra. The measured spectra were compared to those modeled by the TPS, and the effect on patient plans was evaluated. Methods: Transmission measurements were conducted in narrow-beam geometry using a standard Farmer ionization chamber. Two attenuating materials and two build -up caps, having different atomic numbers, served to enhance discrimination between absorption of low and high-energy portions of the spectra, thus improving the accuracy of the results. The data was analyzed using a regularization technique implemented through spreadsheet-based calculations. Results: The unfolded spectra were found to deviate from the TPS beam models. The effect of such deviations on treatment planning was evaluated for patient plans through dose distribution calculations with either TPS modeled or measured energy spectra. The differences were reviewed through comparison of isodose distributions, and quantified based on maximum dose values for critical structures. While in most cases no drastic differences in the calculated doses were observed, plans with deviations of 4 to 8% in the maximum dose values for critical structures were discovered. The anatomical sites with large scatter contributions are the most vulnerable to inaccuracies in the modeled spectrum. Conclusion: An independent check of the TPS model spectrum is highly desirable and should be included as part of commissioning of a new Linac. The effect is particularly important for dose calculations in high heterogeneity regions. The developed approach makes

Superconducting heavy-ion linacs

International Nuclear Information System (INIS)

Bollinger, L.M.

1977-01-01

A summary is given of plans developed by four different groups for the construction of small superconducting linacs to boost the energy of heavy ions from existing tandem electrostatic accelerators. The projects considered are the linac under construction at Argonne and the design efforts at Karlsruhe, at Stanford, and by a Cal Tech-Stony Brook collaboration. The intended uses of the accelerator systems are stated. Beam dynamics of linacs formed of short independently-phased resonators are reviewed, and the implications for performance are discussed. The main parameters of the four linacs are compared, and a brief analysis of accelerating structures is given

Making electron beams for the SLC linac

International Nuclear Information System (INIS)

Clendenin, J.E.; Ecklund, S.D.; James, M.B.; Miller, R.H.; Sheppard, J.C.; Sodja, J.; Truher, J.B.; Minten, A.

1984-01-01

A source of high-intensity, single-bunch electron beams has been developed at SLAC for the SLC. The properties of these beams have been studied extensively utilizing the first 100-m of the SLAC linac and the computer-based control system being developed for the SLC. The source is described and the properties of the beams are summarized. 9 references, 2 figures, 1 table

Superconducting linac booster

International Nuclear Information System (INIS)

Srinivasan, B.; Betigeri, M.G.; Pandey, M.K.; Pillay, R.G.; Kurup, M.B.

1997-01-01

The report on superconducting LINAC booster, which is a joint project of Bhabha Atomic Research Centre (BARC) and Tata Institute of Fundamental Research (TIFR), brings out the work accomplished so far towards the development of the technology of superconducting LINAC to boost the energy of ions from the 14UD Pelletron. The LINAC is modular in construction with each module comprising of a helium cryostat housing four lead-plated quarter wave resonators. The resonators are superconducting for temperatures below 7.19K. An energy boost of 2 MeV/q per module is expected to be achieved. The first module and the post-tandem superbuncher have been fabricated and tested on the LINAC beam line. This report gives a summary of the technological achievements and also brings out the difficulties encountered during the R and D phase. (author)

An overview of BARC-TIFR pelletron linac facility

International Nuclear Information System (INIS)

Gupta, A.K.

2014-01-01

The 14UD Pelletron Accelerator at Mumbai has recently completed twenty five years of successful operation. The accelerator is primarily used for basic research in the fields of nuclear, atomic, condensed matter and material science. The superconducting Linac booster provides additional acceleration to the ions from Pelletron injector up to A∼60 region with E∼5 MeV/A. Further, an alternate injector system to the Superconducting LINAC booster is planned as an augmentation programme, comprising of a superconducting ECR ion source, room temperature RFQ and superconducting low-beta cavity resonators. This talk will provide an overview of the recent developmental activities carried out at the Pelletron Accelerator Facility, resulting in enhanced overall performance and uptime of the accelerator. The application oriented programs initiated at Pelletron Accelerator and the current status of the alternate injector system at the Pelletron-Linac facility will also be discussed. (author)

An overview of BARC-TIFR Pelletron-Linac Facility

International Nuclear Information System (INIS)

Gupta, A. K.

2015-01-01

The 14UD Pelletron Accelerator at Mumbai has recently completed twenty five years of successful operation. The accelerator is primarily used for basic research in the fields of nuclear, atomic, condensed matter and material science. The superconducting Linac booster provides additional acceleration to the ions from Pelletron injector up to A~60 region with E~5 MeV/A. Further, an alternate injector system to the Superconducting LINAC booster is planned as an augmentation programme, comprising of a superconducting ECR ion source, room temperature RFQ and superconducting low-beta cavity resonators. This talk will provide an overview of the recent developmental activities carried out at the Pelletron Accelerator Facility, resulting in enhanced overall performance and uptime of the accelerator. The application oriented programs initiated at Pelletron Accelerator and the current status of the alternate injector system at the Pelletron-Linac facility will also be discussed. (author)

Production of high energy photon beam at TAC

International Nuclear Information System (INIS)

Akkurt, I.; Tekin, H. O.; Demir, N.; Cakirli, R. B.; Akkus, B.; Kupa, I.

2010-01-01

When an electron pass through an electric field, the electron loose its part of energy and photon is generated. This process is known as Bremsstrahlung (means 'radiation breaking' in German) and this photon can be used in a variety of different application. The TAC will be first Turkish Accelerator Center (TAC) where a IR-FEL and Beamstrahlung photon beam facilities will be established in first stage. The electrons will be accelerated up to 40 MeV by two LINAC and these beam will be used to generate Bremsstrahlung photon. In this study, the main parameters for Bremsstrahlung photon beam facility will be established at TAC will be detailed and fields to be used Bremsstrahlung beam will also be presented.

Distributed quantum computing with single photon sources

International Nuclear Information System (INIS)

Beige, A.; Kwek, L.C.

2005-01-01

Full text: Distributed quantum computing requires the ability to perform nonlocal gate operations between the distant nodes (stationary qubits) of a large network. To achieve this, it has been proposed to interconvert stationary qubits with flying qubits. In contrast to this, we show that distributed quantum computing only requires the ability to encode stationary qubits into flying qubits but not the conversion of flying qubits into stationary qubits. We describe a scheme for the realization of an eventually deterministic controlled phase gate by performing measurements on pairs of flying qubits. Our scheme could be implemented with a linear optics quantum computing setup including sources for the generation of single photons on demand, linear optics elements and photon detectors. In the presence of photon loss and finite detector efficiencies, the scheme could be used to build large cluster states for one way quantum computing with a high fidelity. (author)

Proton linac for hospital-based fast neutron therapy and radioisotope production

International Nuclear Information System (INIS)

Lennox, A.J.; Hendrickson, F.R.; Swenson, D.A.; Winje, R.A.; Young, D.E.

1989-09-01

Recent developments in linac technology have led to the design of a hospital-based proton linac for fast neutron therapy. The 180 microamp average current allows beam to be diverted for radioisotope production during treatments while maintaining an acceptable dose rate. During dedicated operation, dose rates greater than 280 neutron rads per minute are achievable at depth, DMAX = 1.6 cm with source to axis distance, SAD = 190 cm. Maximum machine energy is 70 MeV and several intermediate energies are available for optimizing production of isotopes for Positron Emission Tomography and other medical applications. The linac can be used to produce a horizontal or a gantry can be added to the downstream end of the linac for conventional patient positioning. The 70 MeV protons can also be used for proton therapy for ocular melanomas. 17 refs., 1 fig., 1 tab

Mode Engineering of Single Photons from Cavity Spontaneous Parametric Down-Conversion Source and Quantum Dots

Science.gov (United States)

Paudel, Uttam

Over the past decade, much effort has been made in identifying and characterizing systems that can form a building block of quantum networks, among which semiconductor quantum dots (QD) and spontaneous parametric down-conversion (SPDC) source are two of the most promising candidates. The work presented in this thesis will be centered on investigating and engineering the mentioned systems for generating customizable single photons. A type-II SPDC source can generate a highly flexible pair of entangled photons that can be used to interface disparate quantum systems. In this thesis, we have successfully implemented a cavity-SPDC source that emits polarization correlated photons at 942 nm with a lifetime of 950-1050ps that mode matches closely with InAs/GaAs QD photons. The source emits 80 photon pairs per second per mW pump power within the 150MHz bandwidth. Though the detection of idler photons, the source is capable of emitting heralded photons with g2?0.5 for up to 40 mW pump power. For a low pump power of 5 mW, the heralded g2 is 0.06, indicating that the system is an excellent heralded single photon source. By directly exciting a single QD with cavity-SPDC photons, we have demonstrated a heralded-absorption of SPDC photons by QD, resulting in the coupling of the two systems. Due to the large pump bandwidth, the emitted source is highly multimode in nature, requiring us to post-filter the downconverted field, resulting in a lower photon pair emission rate. We propose placing an intra-cavity etalon to suppress the multi-mode emissions and increase the photon count rate. Understanding and experimentally implementing two-photon interference (HOM) measurements will be crucial for building a scalable quantum network. A detailed theoretical description of HOM measurements is given and is experimentally demonstrated using photons emitted by QD. Through HOM measurements we demonstrated that the QD sample in the study is capable of emitting indistinguishable photons, with

Characterization of our source of polarization-entangled photons

Science.gov (United States)

Adenier, Guillaume

2012-12-01

We present our source of polarization entangled photons, which consist of orthogonally polarized and collinear parametric down converted photons sent to the same input of a nonpolarizing beam splitter. We show that a too straightforward characterization of the quantum state cannot account for all the experimental observations, in particular for the behavior of the doublecounts, which are the coincidences produced whenever both photons are dispatched by the beam splitter to the same measuring station (either Alice or Bob). We argue that in order to account for all observations, the state has to be entangled in polarization before the non-polarizing beam splitter, and we discuss the intriguing and nevertheless essential role of the time-compensation required to obtain such a polarization entanglement.

Qubit entanglement between ring-resonator photon-pair sources on a silicon chip

Science.gov (United States)

Silverstone, J. W.; Santagati, R.; Bonneau, D.; Strain, M. J.; Sorel, M.; O'Brien, J. L.; Thompson, M. G.

2015-01-01

Entanglement—one of the most delicate phenomena in nature—is an essential resource for quantum information applications. Scalable photonic quantum devices must generate and control qubit entanglement on-chip, where quantum information is naturally encoded in photon path. Here we report a silicon photonic chip that uses resonant-enhanced photon-pair sources, spectral demultiplexers and reconfigurable optics to generate a path-entangled two-qubit state and analyse its entanglement. We show that ring-resonator-based spontaneous four-wave mixing photon-pair sources can be made highly indistinguishable and that their spectral correlations are small. We use on-chip frequency demultiplexers and reconfigurable optics to perform both quantum state tomography and the strict Bell-CHSH test, both of which confirm a high level of on-chip entanglement. This work demonstrates the integration of high-performance components that will be essential for building quantum devices and systems to harness photonic entanglement on the large scale. PMID:26245267

Report of the design study on the proton linac of the Japanese Hadron Project, 2

International Nuclear Information System (INIS)

1990-06-01

The design study on the proton linac of the Japanese Hadron Project began in May 1987, in the collaboration of Institute for Nuclear Study, University of Tokyo and National Laboratory for High Energy Physics. This is the second report of the design study on the 1-GeV proton linac, which includes the developments of the ion source, RFQ, DTL, CCL and RF sources. (author)

Status report on the Advanced Photon Source Project at Argonne National Laboratory

International Nuclear Information System (INIS)

Huebner, R.H. Sr.

1989-01-01

The Advanced Photon Source at Argonne National Laboratory is designed as a national synchrotron radiation user facility which will provide extremely bright, highly energetic x-rays for multidisciplinary research. When operational, the Advanced Photon Source will accelerate positrons to a nominal energy of 7 GeV. The positrons will be manipulated by insertion devices to produce x-rays 10,000 times brighter than any currently available for research. Accelerator components, insertion devices, optical elements, and optical-element cooling schemes have been and continue to be the subjects of intensive research and development. A call for Letters of Intent from prospective users of the Advanced Photon Source has resulted in a substantial response from industrial, university, and national laboratory researchers

Interference with a quantum dot single-photon source and a laser at telecom wavelength

Energy Technology Data Exchange (ETDEWEB)

Felle, M. [Toshiba Research Europe Limited, Cambridge Research Laboratory, 208 Cambridge Science Park, Milton Road, Cambridge CB4 0GZ (United Kingdom); Centre for Advanced Photonics and Electronics, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Huwer, J., E-mail: jan.huwer@crl.toshiba.co.uk; Stevenson, R. M.; Skiba-Szymanska, J.; Ward, M. B.; Shields, A. J. [Toshiba Research Europe Limited, Cambridge Research Laboratory, 208 Cambridge Science Park, Milton Road, Cambridge CB4 0GZ (United Kingdom); Farrer, I.; Ritchie, D. A. [Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Penty, R. V. [Centre for Advanced Photonics and Electronics, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0FA (United Kingdom)

2015-09-28

The interference of photons emitted by dissimilar sources is an essential requirement for a wide range of photonic quantum information applications. Many of these applications are in quantum communications and need to operate at standard telecommunication wavelengths to minimize the impact of photon losses and be compatible with existing infrastructure. Here, we demonstrate for the first time the quantum interference of telecom-wavelength photons from an InAs/GaAs quantum dot single-photon source and a laser; an important step towards such applications. The results are in good agreement with a theoretical model, indicating a high degree of indistinguishability for the interfering photons.

Interference with a quantum dot single-photon source and a laser at telecom wavelength

International Nuclear Information System (INIS)

Felle, M.; Huwer, J.; Stevenson, R. M.; Skiba-Szymanska, J.; Ward, M. B.; Shields, A. J.; Farrer, I.; Ritchie, D. A.; Penty, R. V.

2015-01-01

The interference of photons emitted by dissimilar sources is an essential requirement for a wide range of photonic quantum information applications. Many of these applications are in quantum communications and need to operate at standard telecommunication wavelengths to minimize the impact of photon losses and be compatible with existing infrastructure. Here, we demonstrate for the first time the quantum interference of telecom-wavelength photons from an InAs/GaAs quantum dot single-photon source and a laser; an important step towards such applications. The results are in good agreement with a theoretical model, indicating a high degree of indistinguishability for the interfering photons

The Advanced Photon Source: Performance and results from early operation

International Nuclear Information System (INIS)

Moncton, D.E.

1997-01-01

The Advanced Photon Source at Argonne National Laboratory is now providing researchers with extreme-brilliance undulator radiation in the hard x-ray region of the spectrum. All technical facilities and components are operational and have met design specifications. Fourteen research teams, occupying 20 sectors on the APS experiment hall floor, are currently installing beamline instrumentation or actively taking data. An overview is presented for the first operational years of the Advanced Photon Source. Emphasis is on the performance of accelerators and insertion devices, as well as early scientific results and future plans

A novel high-efficiency single-mode quantum dot single photon source

DEFF Research Database (Denmark)

Gerard, J.M.; Gregersen, Niels; Nielsen, Torben Roland

2008-01-01

We present a novel single-mode single photon source exploiting the emission of a semiconductor quantum dot (QD) located inside a photonic wire. Besides an excellent coupling (>95%) of QD spontaneous emission to the fundamental guided mode [1], we show that a single photon collection efficiency...... above 80% within a 0.5 numerical aperture can be achieved using a bottom Bragg mirror and a tapering of the nanowire tip. Because this photon collection strategy does not exploit the Purcell effect, it could also be efficiently applied to broadband single photon emitters such as F-centers in diamond....

Performance of a beam-multiplexing diamond crystal monochromator at the Linac Coherent Light Source

International Nuclear Information System (INIS)

Zhu, Diling; Feng, Yiping; Lemke, Henrik T.; Fritz, David M.; Chollet, Matthieu; Glownia, J. M.; Alonso-Mori, Roberto; Sikorski, Marcin; Song, Sanghoon; Williams, Garth J.; Messerschmidt, Marc; Boutet, Sébastien; Robert, Aymeric; Stoupin, Stanislav; Shvyd'ko, Yuri V.; Terentyev, Sergey A.; Blank, Vladimir D.; Driel, Tim B. van

2014-01-01

A double-crystal diamond monochromator was recently implemented at the Linac Coherent Light Source. It enables splitting pulses generated by the free electron laser in the hard x-ray regime and thus allows the simultaneous operations of two instruments. Both monochromator crystals are High-Pressure High-Temperature grown type-IIa diamond crystal plates with the (111) orientation. The first crystal has a thickness of ∼100 μm to allow high reflectivity within the Bragg bandwidth and good transmission for the other wavelengths for downstream use. The second crystal is about 300 μm thick and makes the exit beam of the monochromator parallel to the incoming beam with an offset of 600 mm. Here we present details on the monochromator design and its performance

Construction of SPring-8 LINAC

International Nuclear Information System (INIS)

Yokomizo, Hideaki; Yoshikawa, Hiroshi; Suzuki, Shinsuke; Yanagida, Ken-ichi; Mizuno, Akihiko; Hori, Toshihiko; Tamezane, Kenji; Kodera, Masahiko; Sakaki, Hironao; Mashiko, Katsuo

1993-01-01

Construction of the linac building has been started in February 1993. The components of the linac are under manufacturing. The preinjector of linac was already constructed and temporarily installed in Tokai Establishment in order to test the beam quality. (author)

Third order mode laser diode: design of a twin photon source

International Nuclear Information System (INIS)

Ducci, S.; Berger, V.; Rossi, A. de; Ortiz, V.; Calligaro, M.; Vinter, B.; Nagle, J.; Berger, V.

2004-01-01

We demonstrate the lasing action on a third order waveguide mode in a laser diode. The AlGaAs heterostructure has been designed to achieve a parametric emission of photons pairs through modal phase matching. This device is very compact and does not generate coupling loss between the laser source and the non-linear waveguide. It is the first step on the way to design a twin photon micro-source. (A.C.)

Post-processing with linear optics for improving the quality of single-photon sources

International Nuclear Information System (INIS)

Berry, Dominic W; Scheel, Stefan; Myers, Casey R; Sanders, Barry C; Knight, Peter L; Laflamme, Raymond

2004-01-01

Triggered single-photon sources produce the vacuum state with non-negligible probability, but produce a much smaller multiphoton component. It is therefore reasonable to approximate the output of these photon sources as a mixture of the vacuum and single-photon states. We show that it is impossible to increase the probability for a single photon using linear optics and photodetection on fewer than four modes. This impossibility is due to the incoherence of the inputs; if the inputs were pure-state superpositions, it would be possible to obtain a perfect single-photon output. In the more general case, a chain of beam splitters can be used to increase the probability for a single photon, but at the expense of adding an additional multiphoton component. This improvement is robust against detector inefficiencies, but is degraded by distinguishable photons, dark counts or multiphoton components in the input

Linac pre-injector

CERN Multimedia

CERN PhotoLab

1965-01-01

New accelerating column of the linac pre-injector, supporting frame and pumping system. This new system uses two mercury diffusion pumps (in the centre) and forms part of the modifications intended to increase the intensity of the linac. View taken during assembly in the workshop.

On-demand semiconductor single-photon source with near-unity indistinguishability.

Science.gov (United States)

He, Yu-Ming; He, Yu; Wei, Yu-Jia; Wu, Dian; Atatüre, Mete; Schneider, Christian; Höfling, Sven; Kamp, Martin; Lu, Chao-Yang; Pan, Jian-Wei

2013-03-01

Single-photon sources based on semiconductor quantum dots offer distinct advantages for quantum information, including a scalable solid-state platform, ultrabrightness and interconnectivity with matter qubits. A key prerequisite for their use in optical quantum computing and solid-state networks is a high level of efficiency and indistinguishability. Pulsed resonance fluorescence has been anticipated as the optimum condition for the deterministic generation of high-quality photons with vanishing effects of dephasing. Here, we generate pulsed single photons on demand from a single, microcavity-embedded quantum dot under s-shell excitation with 3 ps laser pulses. The π pulse-excited resonance-fluorescence photons have less than 0.3% background contribution and a vanishing two-photon emission probability. Non-postselective Hong-Ou-Mandel interference between two successively emitted photons is observed with a visibility of 0.97(2), comparable to trapped atoms and ions. Two single photons are further used to implement a high-fidelity quantum controlled-NOT gate.

Experiments and prospects for induction linac drivers

International Nuclear Information System (INIS)

Keefe, D.

1986-05-01

In the last three years, the US program in Heavy Ion Fusion has concentrated on understanding the induction linac approach to a power-plant driver. In this method it is important that the beam current be maximized throughout the accelerator. Consequently, it is crucial to understand the space-charge limit in the AG transport system in the linac and, also, to achieve current amplification during acceleration to keep pace with the kinematical increase of this limit with energy. Experimental results on both these matters and also on the use of multiple beams (inside the same accelerating structure) will be described. A new examination of the most attractive properties of the induction linac for a fusion driver has clearly pointed to the advantage of using heavy ions with a charge-state greater than unity - perhaps q = 3 may be an optimum. This development places even greater importance on understanding space-charge limits and mechanisms for emittance growth; also, it will require a new emphasis on the development of a suitable ion source

Experiments and prospects for induction linac drivers

International Nuclear Information System (INIS)

Keefe, D.

1986-12-01

In the last three years, the US program in Heavy Ion Fusion has concentrated on understanding the induction linac approach to a power-plant driver. In this method it is important that the beam current be maximized throughout the accelerator. Consequently, it is crucial to understand the space-charge limit in the AG transport system in the linac and, also, to achieve current amplification during acceleration to keep pace with the kinematical increase of this limit with energy. Experimental results on both these matters and also on the use of multiple beams (inside the same accelerating structure) will be described. A new examination of the most attractive properties of the induction linac for a fusion driver has clearly pointed to the advantage of using heavy ions with a charge-state greater than unity - perhaps q = 3 may be an optimum. This development places even greater importance on understanding space-charge limits and mechanisms for emittance growth; also, it will require a new emphasis on the development of a suitable ion source

Redesign of the low energy section of the Fermilab linac to improve beam brightness

International Nuclear Information System (INIS)

Schmidt, C.; Noble, R.; Palkovic, J.; Mills, F.E.

1988-10-01

The critical parameters which limit the luminosity of the Fermilab Tevatron Collider are the beam emittances, both longitudinal and transverse, at each stage in the acceleration sequence. Improvements to reduce invariant emittance growth at earlier acceleration stages necessarily encourage improvements in all downstream stages. Recent advances in linac technology should permit a significant increase in the beam brightness of the Fermilab linac. A redesign of the low energy section of the linac is envisioned to include a circular aperture H/sup /minus// source, a short 30-keV transport line (solenoids, Gabor lenses or einzel lenses) for matching to a radio frequency quadrupole linac (RFQ), and injection at approximately 2 MeV into a new 200 MHz Alvarez linac tank for acceleration to 10 MeV. 9 refs., 1 fig

Linacs for medical isotope production

International Nuclear Information System (INIS)

Pramudita, A.

2012-01-01

This paper reviews efforts on using high energy (25-30 MeV) and high power (10-20 kW) electron linacs and lower energy (7 MeV) proton linacs for medical radioisotope production. Using high energy x-rays from the electron linacs, PET (Positron Emission Tomography) radioisotopes are produced through photonuclear reactions such as 19 F(γ,n) 18 F, which also allow production of other PET radionuclides 11 C, 13 N, and 15 O. Other mostly used medical radionuclides 99m Tc can also be obtained by using the electron linacs, through photofission or photonuclear reactions. Proton linacs for PET have also been recently developed and the product has been available in the market since 2005. The linacs have been tested for 18 F production. As a proton accelerator, the target systems and nuclear reactions are similar to the ones used in PET cyclotrons. (author)

LCLS in—photon out: fluorescence measurement of neon using soft x-rays

Science.gov (United States)

Obaid, Razib; Buth, Christian; Dakovski, Georgi L.; Beerwerth, Randolf; Holmes, Michael; Aldrich, Jeff; Lin, Ming-Fu; Minitti, Michael; Osipov, Timur; Schlotter, William; Cederbaum, Lorenz S.; Fritzsche, Stephan; Berrah, Nora

2018-02-01

We measured the fluorescence photon yield of neon upon soft x-ray ionization (∼1200 eV) from the x-ray free-electron laser at Linac Coherent Light Source, and demonstrated the usage of a grazing incidence spectrometer with a variable line spacing grating to perform x-ray fluorescence spectroscopy on a gas phase system. Our measurements also allowed us to estimate the focal size of the beam from the theoretical description developed, in terms of the rate equation approximation accounting for photoionization shake off of neutral neon and double auger decay of single core holes.

Linac4 Technical Design Report

CERN Document Server

Arnaudon, L; Baylac, M; Bellodi, G; Body, Y; Borburgh, J; Bourquin, P; Broere, J; Brunner, O; Bruno, L; Carli, C; Caspers, Friedhelm; Cousineau, S M; Cuvet, Y; De Almeida Martins, C; Dobers, T; Fowler, T; Garoby, R; Gerigk, F; Goddard, B; Hanke, K; Hori, M; Jones, M; Kahle, K; Kalbreier, Willi; Kroyer, T; Küchler, D; Lombardi, A M; López-Hernandez, L A; Magistris, M; Martini, M; Maury, S; Page, E; Paoluzzi, M; Pasini, M; Raich, U; Rossi, C; Royer, J P; Sargsyan, E; Serrano, J; Scrivens, R; Silari, M; Timmins, M; Venturini-Delsolaro, W; Vretenar, M; Wegner, R; Weterings, W; Zickler, T

2006-01-01

Linac4 is an H- linear accelerator, intended to replace Linac2 as injector to the PS Booster (PSB). By delivering to the PSB a beam at 160 MeV energy, Linac4 will provide the conditions to double the brightness and intensity of the beam from the PSB, thus removing the first bottleneck towards higher brightness for the LHC and simplifying operation. Moreover, this new linac constitutes an essential component of any of the envisaged LHC upgrade scenarios and could open the way to future extensions of the CERN accelerator complex towards higher performance. This Technical Design Report presents a detailed technical overview of the Linac4 design as it stands at end 2006.

Bright nanoscale source of deterministic entangled photon pairs violating Bell's inequality

NARCIS (Netherlands)

Jöns, K.D.; Schweickert, L.S.; Versteegh, M.A.M.; Dalacu, Dan; Poole, Philip J.; Gulinatti, Angelo; Giudice, Andrea; Zwiller, V.G.; Reimer, M.E.

2017-01-01

Global, secure quantum channels will require efficient distribution of entangled photons. Long distance, low-loss interconnects can only be realized using photons as quantum information carriers. However, a quantum light source combining both high qubit fidelity and on-demand bright emission has

TOP LINAC design; Progetto del TOP LINAC

Energy Technology Data Exchange (ETDEWEB)

Picardi, L; Ronsivalle, C; Vignati, A [ENEA, Centro Ricerche Frascati, Rome (Italy). Dip. Innovazione

1997-11-01

The report describes a linear accelerator for protons named TOP LINAC designed for the TOP (Terapia Oncologica con Protoni, Oncological Protontherapy) project launched by the Italian National Institute of Health (Istituto Superiore di Sanita`, ISS) to explore in collaboration with the biggest Oncological Hospital in Rome (Istituto Regina Elena, IRE) the potentialities of the therapy with accelerated protons and establish guide lines for the application of this new type of radiotherapy in comparison with the more traditional electron and x-rays radiotherapy. The concept of a compact accelerator for protontherapy applications bore within the Italian Hadrontherapy Collaboration (TERA Collaboration) with the aim to diffuse the protontherapy on the National territory. The ISS program plans to use the TOP linac proton beam also for production of PET (Positron Emission Tomography) radioisotopes and radiobiology studies. Official agreements are in course between ISS and ENEA which provides its experience in the industrial and medical accelerators for the design and the construction of the TOP linac. The accelerator that will be the first 3 GHz proton linac in the world, will be composed of a 428.3 MHz 7 Me V RFQ + DTL injector followed by a 7-65 Me V section of a 3 GHz SCDTL structure and a 65 - 200 Me V variable energy SCL 3 GHz structure. In particular the SCDTL section uses a highly innovative accelerating structure patented by ENEA. In this report the clinical and physical requests are discussed and a preliminary design of the whole machine is given.

LINAC based stereotactic radiotherapy of uveal melanoma: 4 years clinical experience

International Nuclear Information System (INIS)

Dieckmann, Karin; Georg, Dietmar; Zehetmayer, Martin; Bogner, Joachim; Georgopoulos, Michael; Poetter, Richard

2003-01-01

Purpose: To study local tumor control and radiogenic side effects after fractionated LINAC based stereotactic radiotherapy for selected uveal melanoma. Patients and methods: Between June 1997 and March 2001, 90 patients suffering from uveal melanoma were treated at a LINAC with 6 MV. The head was immobilized with a modified stereotactic frame system (BrainLAB). For stabilization of the eye position a light source was integrated into the mask system in front of the healthy or the diseased eye. A mini-video camera was used for on-line eye movement control. Tumors included in the study were either located unfavorably with respect to macula and optical disc ( 7 mm. Median tumor volume was 305±234 mm 3 (range 70-1430 mm 3 ), and mean tumor height was 5.4±2.3 mm (range 2.7-15.9 mm). Total doses of 70 (single dose 14 Gy at 80% isodose) or 60 Gy (single dose 12 Gy at 80% isodose) were applied in five fractions within 10 days. The first fractionation results in total dose (TD) (2 Gy) of 175 Gy for tumor and 238 Gy for normal tissue, corresponding values for the second fractionation schedule are 135 and 180 Gy, respectively. Results: After a median follow-up of 20 months (range 1-48 months) local control was achieved in 98% (n=88). The mean relative tumor reductions were 24, 27, and 37% after 12, 24 and 36 months. Three patients (3.3%) developed metastases. Secondary enucleation was performed in seven patients (7.7%). Long term side effects were retinopathy (25.5%), cataract (18.9%), optic neuropathy (20%), and secondary neovascular glaucoma (8.8%). Conclusion: Fractionated LINAC based stereotactic photon beam therapy in conjunction with a dedicated eye movement control system is a highly effective method to treat unfavorably located uveal melanoma. Total doses of 60 Gy (single dose 12 Gy) are considered to be sufficient to achieve good local tumor control

Inner structure of Linac 2

CERN Multimedia

CERN PhotoLab

1977-01-01

With the advent of the 800 MeV Booster in 1972, the original injector of the PS, a 50 MeV Alvarez-type proton linac, had reached its limits, in terms of intensity and stability. In 1973 one therefore decided to build a new linac (Linac 2), also with a drift-tube Alvarez structure and an energy of 50 MeV. It had a new Cockcroft-Walton preinjector with 750 keV, instead of the previous one with 500 keV. Linac 2 was put into service in 1980. The old Linac 1 was then used for the study of, and later operation with, various types of ions. This picture shows the inner structure of Linac 2, with drift-tubes hanging on stems under a rigid support structure, soon to be mounted inside tank 1 (750 keV to 10 MeV, the lowest-energy one of 3). Frank Malthouse is standing in the background.

Photon spectrum and absorbed dose in brain tumor

Energy Technology Data Exchange (ETDEWEB)

Silva S, A. [General Electric Healthcare, Antonio Dovali Jaime 70, Torre A 3er. piso, Col. Santa Fe, 01210 Mexico D. F. (Mexico); Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico); Rivera M, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria No. 694, 11500 Mexico D. F. (Mexico)

2015-10-15

Using Monte Carlo methods a BOMAB phantom inside a treatment hall with a brain tumor nearby the pituitary gland was treated with photons produced by a Varian 6 MV linac. The photon spectrum and the absorbed dose were calculated in the tumor, pituitary gland and the head. The treatment beam was collimated to illuminate only the tumor volume; however photons were noticed in the gland. Photon fluence reaching the tumor is 78.1 times larger than the fluence in the pituitary gland, on the other hand the absorbed dose in the tumor is 188 times larger than the dose in the gland because photons that reach the pituitary gland are scattered, by the head and the tumor, through Compton effect. (Author)

Photon spectrum and absorbed dose in brain tumor

International Nuclear Information System (INIS)

Silva S, A.; Vega C, H. R.; Rivera M, T.

2015-10-01

Using Monte Carlo methods a BOMAB phantom inside a treatment hall with a brain tumor nearby the pituitary gland was treated with photons produced by a Varian 6 MV linac. The photon spectrum and the absorbed dose were calculated in the tumor, pituitary gland and the head. The treatment beam was collimated to illuminate only the tumor volume; however photons were noticed in the gland. Photon fluence reaching the tumor is 78.1 times larger than the fluence in the pituitary gland, on the other hand the absorbed dose in the tumor is 188 times larger than the dose in the gland because photons that reach the pituitary gland are scattered, by the head and the tumor, through Compton effect. (Author)

On-demand generation of background-free single photons from a solid-state source

Science.gov (United States)

Schweickert, Lucas; Jöns, Klaus D.; Zeuner, Katharina D.; Covre da Silva, Saimon Filipe; Huang, Huiying; Lettner, Thomas; Reindl, Marcus; Zichi, Julien; Trotta, Rinaldo; Rastelli, Armando; Zwiller, Val

2018-02-01

True on-demand high-repetition-rate single-photon sources are highly sought after for quantum information processing applications. However, any coherently driven two-level quantum system suffers from a finite re-excitation probability under pulsed excitation, causing undesirable multi-photon emission. Here, we present a solid-state source of on-demand single photons yielding a raw second-order coherence of g(2 )(0 )=(7.5 ±1.6 )×10-5 without any background subtraction or data processing. To this date, this is the lowest value of g(2 )(0 ) reported for any single-photon source even compared to the previously reported best background subtracted values. We achieve this result on GaAs/AlGaAs quantum dots embedded in a low-Q planar cavity by employing (i) a two-photon excitation process and (ii) a filtering and detection setup featuring two superconducting single-photon detectors with ultralow dark-count rates of (0.0056 ±0.0007 ) s-1 and (0.017 ±0.001 ) s-1, respectively. Re-excitation processes are dramatically suppressed by (i), while (ii) removes false coincidences resulting in a negligibly low noise floor.

Quantum key distribution with entangled photon sources

International Nuclear Information System (INIS)

Ma Xiongfeng; Fung, Chi-Hang Fred; Lo, H.-K.

2007-01-01

A parametric down-conversion (PDC) source can be used as either a triggered single-photon source or an entangled-photon source in quantum key distribution (QKD). The triggering PDC QKD has already been studied in the literature. On the other hand, a model and a post-processing protocol for the entanglement PDC QKD are still missing. We fill in this important gap by proposing such a model and a post-processing protocol for the entanglement PDC QKD. Although the PDC model is proposed to study the entanglement-based QKD, we emphasize that our generic model may also be useful for other non-QKD experiments involving a PDC source. Since an entangled PDC source is a basis-independent source, we apply Koashi and Preskill's security analysis to the entanglement PDC QKD. We also investigate the entanglement PDC QKD with two-way classical communications. We find that the recurrence scheme increases the key rate and the Gottesman-Lo protocol helps tolerate higher channel losses. By simulating a recent 144-km open-air PDC experiment, we compare three implementations: entanglement PDC QKD, triggering PDC QKD, and coherent-state QKD. The simulation result suggests that the entanglement PDC QKD can tolerate higher channel losses than the coherent-state QKD. The coherent-state QKD with decoy states is able to achieve highest key rate in the low- and medium-loss regions. By applying the Gottesman-Lo two-way post-processing protocol, the entanglement PDC QKD can tolerate up to 70 dB combined channel losses (35 dB for each channel) provided that the PDC source is placed in between Alice and Bob. After considering statistical fluctuations, the PDC setup can tolerate up to 53 dB channel losses

Pleiades: A Sub-picosecond Tunable X-ray Source at the LLNL Electron Linac

International Nuclear Information System (INIS)

Slaughter, Dennis; Springer, Paul; Le Sage, Greg; Crane, John; Ditmire, Todd; Cowan, Tom; Anderson, Scott G.; Rosenzweig, James B.

2002-01-01

The use of ultra fast laser pulses to generate very high brightness, ultra short (fs to ps) pulses of x-rays is a topic of great interest to the x-ray user community. In principle, femto-second-scale pump-probe experiments can be used to temporally resolve structural dynamics of materials on the time scale of atomic motion. The development of sub-ps x-ray pulses will make possible a wide range of materials and plasma physics studies with unprecedented time resolution. A current project at LLNL will provide such a novel x-ray source based on Thomson scattering of high power, short laser pulses with a high peak brightness, relativistic electron bunch. The system is based on a 5 mm-mrad normalized emittance photo-injector, a 100 MeV electron RF linac, and a 300 mJ, 35 fs solid-state laser system. The Thomson x-ray source produces ultra fast pulses with x-ray energies capable of probing into high-Z metals, and a high flux per pulse enabling single shot experiments. The system will also operate at a high repetition rate (∼ 10 Hz). (authors)

Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

For the application of photon to industrial technologies, in particular, a hard photon technology was surveyed which uses photon beams of 0.1-200nm in wavelength. Its features such as selective atom reaction, dense inner shell excitation and spacial high resolution by quantum energy are expected to provide innovative techniques for various field such as fine machining, material synthesis and advanced inspection technology. This wavelength region has been hardly utilized for industrial fields because of poor development of suitable photon sources and optical devices. The developmental meaning, usable time and issue of a hard photon reduction lithography were surveyed as lithography in ultra-fine region below 0.1{mu}m. On hard photon analysis/evaluation technology, the industrial use of analysis, measurement and evaluation technologies by micro-beam was viewed, and optimum photon sources and optical systems were surveyed. Prediction of surface and surface layer modification by inner shell excitation, the future trend of this process and development of a vacuum ultraviolet light source were also surveyed. 383 refs., 153 figs., 17 tabs.

Linacs for medical and industrial applications

International Nuclear Information System (INIS)

Hamm, R.W.

1986-01-01

Linear accelerators for medical and industrial applications have become an important commercial business. Microwave electron linacs for cancer radiation therapy and high-energy industrial radiography form the bulk of this market, but these, as well as induction linacs, are now being offered for radiation processing applications such as sterilization of disposable medical products, food preservation and material modifications. The radio frequency quadrupole (RFQ) linac has now made the ion linac also practical for commercial applications in medicine and industry, including radiation therapy, isotope production, neutron production, materials modification, and energy transfer processes. Ion linacs for several of these applications will soon be commercially available. The market for both ion and electron linacs is expected to significantly grow in several exciting and important areas

Photon contributions from the 252Cf and 241Am–Be neutron sources at the PSI Calibration Laboratory

International Nuclear Information System (INIS)

Hoedlmoser, H.; Boschung, M.; Meier, K.; Stadtmann, H.; Hranitzky, C.; Figel, M.; Mayer, S.

2012-01-01

At the accredited PSI Calibration Laboratory neutron reference fields traceable to the national standards of the Physikalisch-Technische Bundesanstalt (PTB) in Germany are available for the calibration of ambient and personal dose equivalent (rate) meters and passive dosimeters. The photon contribution to the ambient dose equivalent in the neutron fields of the 252 Cf and 241 Am–Be sources was measured using various photon dose rate meters and active and passive dosimeters. Measuring photons from a neutron source usually involves considerable uncertainties due to the presence of neutron induced photons in the room, due to a non-zero neutron sensitivity of the photon detector, and last but not least due to the energy response of the photon detectors. Therefore eight independent detectors and methods were used to obtain a reliable estimate for the photon contribution of the two sources as an average of the individual methods. For the 241 Am–Be source a photon contribution of approximately 4.9% was determined and for the 252 Cf source a contribution of 3.6%.

Stable single-photon source in the near infrared

International Nuclear Information System (INIS)

Gaebel, T; Popa, I; Gruber, A; Domhan, M; Jelezko, F; Wrachtrup, J

2004-01-01

Owing to their unsurpassed photostability, defects in solids may be ideal candidates for single-photon sources. Here we report on generation of single photons by optical excitation of a yet unexplored defect in diamond, the nickel-nitrogen complex (NE8) centre. The most striking feature of the defect is its emission bandwidth of 1.2 nm at room temperature. The emission wavelength of the defect is around 800 nm, which is suitable for telecom fibres. In addition, in this spectral region little background light from the diamond bulk material is detected. Consequently, a high contrast in antibunching measurements is achieved

Testing begins on Linac4

CERN Multimedia

Katarina Anthony

2012-01-01

On 3 August 2012, the Linac4 radiofrequency quadrupole (RFQ) module was installed at the accelerator test-stand in Building 152. The site will be the module’s home for almost a year, as the linear accelerator enters the assembly and testing stage.   Final module assembly is carried out before installation in Building 152.  Over the next Long Shutdown (LS2), Linac4 will replace the current Linac2 linear accelerator as the first link in CERN’s accelerator chain. It will deliver particles at 160 MeV to the PS Booster, more than triple the energy currently delivered by Linac2. But before the accelerator team can pop the champagne, the various elements of Linac4 will be tested and re-tested in facilities across CERN. “The first Linac4 tests are currently underway, starting with the CERN-built RFQ,” says Carlo Rossi, a physicist in the RF Group of the Beams (BE) Department and the RFQ project coordinator. “It’s an extremely impre...

Determination of discharge parameters via OES at the Linac4 H− ion source

International Nuclear Information System (INIS)

Briefi, S.; Fink, D.; Mattei, S.; Lettry, J.; Fantz, U.

2016-01-01

Optical emission spectroscopy (OES) measurements of the atomic Balmer series and the molecular Fulcher transition have been carried out at the Linac4 ion source in order to determine plasma parameters. As the spectroscopic system was only relatively calibrated, the data evaluation only yielded rough estimates of the plasma parameters (T e ≈ 1.2 eV, n e ≈ 1 × 10 19 m −3 , and n H /n H 2 ≈ 0.5 at standard operational parameters). The analysis of the Fulcher transition revealed a non-thermal “hockey-stick” rotational population of the hydrogen molecules. At varying RF power, the measurements at the on-axis line of sight (LOS) showed a peak in the rotational temperatures between 25 and 40 kW of RF power, whereas a steady decrease with power was observed at a tilted LOS, indicating the presence of strong plasma parameter gradients

A theoretical model for the production of Ac-225 for cancer therapy by photon-induced transmutation of Ra-226.

Science.gov (United States)

Melville, G; Fan Liu, Sau; Allen, B J

2006-09-01

Radium needles that were once implanted into tumours as a cancer treatment are now obsolete and constitute a radioactive waste problem, as their half-life is 1600 years. We are investigating the reduction of radium by transmutation on a small scale by bombarding Ra-226 with high-energy photons from a medical linear accelerator (linac) to produce Ra-225, which subsequently decays to Ac-225, which can be used as a generator to produce Bi-213 for use in 'targeted alpha therapy' for cancer. This paper examines the possibility of producing Ac-225 with a linac using an accurate theoretical model in which the bremsstrahlung photon spectrum at 18 MV linac electron energy is convoluted with the corresponding photonuclear cross sections of Ra-226. The total integrated yield can then be obtained and is compared with a computer simulation. This study shows that at 18 MV, the photonuclear reaction on Ra-226 can produce low activities of Ac-225 with a linac. However, a high power linac with high current, pulse length and frequency is needed to produce practical amounts of Ac-225 and a useful reduction of Ra-226.

PERLE. Powerful energy recovery linac for experiments. Conceptual design report

Science.gov (United States)

Angal-Kalinin, D.; Arduini, G.; Auchmann, B.; Bernauer, J.; Bogacz, A.; Bordry, F.; Bousson, S.; Bracco, C.; Brüning, O.; Calaga, R.; Cassou, K.; Chetvertkova, V.; Cormier, E.; Daly, E.; Douglas, D.; Dupraz, K.; Goddard, B.; Henry, J.; Hutton, A.; Jensen, E.; Kaabi, W.; Klein, M.; Kostka, P.; Lasheras, N.; Levichev, E.; Marhauser, F.; Martens, A.; Milanese, A.; Militsyn, B.; Peinaud, Y.; Pellegrini, D.; Pietralla, N.; Pupkov, Y.; Rimmer, R.; Schirm, K.; Schulte, D.; Smith, S.; Stocchi, A.; Valloni, A.; Welsch, C.; Willering, G.; Wollmann, D.; Zimmermann, F.; Zomer, F.

2018-06-01

A conceptual design is presented of a novel energy-recovering linac (ERL) facility for the development and application of the energy recovery technique to linear electron accelerators in the multi-turn, large current and large energy regime. The main characteristics of the powerful energy recovery linac experiment facility (PERLE) are derived from the design of the Large Hadron electron Collider, an electron beam upgrade under study for the LHC, for which it would be the key demonstrator. PERLE is thus projected as a facility to investigate efficient, high current (HC) (>10 mA) ERL operation with three re-circulation passages through newly designed SCRF cavities, at 801.58 MHz frequency, and following deceleration over another three re-circulations. In its fully equipped configuration, PERLE provides an electron beam of approximately 1 GeV energy. A physics programme possibly associated with PERLE is sketched, consisting of high precision elastic electron–proton scattering experiments, as well as photo-nuclear reactions of unprecedented intensities with up to 30 MeV photon beam energy as may be obtained using Fabry–Perot cavities. The facility has further applications as a general technology test bed that can investigate and validate novel superconducting magnets (beam induced quench tests) and superconducting RF structures (structure tests with HC beams, beam loading and transients). Besides a chapter on operation aspects, the report contains detailed considerations on the choices for the SCRF structure, optics and lattice design, solutions for arc magnets, source and injector and on further essential components. A suitable configuration derived from the here presented design concept may next be moved forward to a technical design and possibly be built by an international collaboration which is being established.

Dye molecules as single-photon sources and large optical nonlinearities on a chip

International Nuclear Information System (INIS)

Hwang, J; Hinds, E A

2011-01-01

We point out that individual organic dye molecules, deposited close to optical waveguides on a photonic chip, can act as single-photon sources. A thin silicon nitride strip waveguide is expected to collect 28% of the photons from a single dibenzoterrylene molecule. These molecules can also provide large, localized optical nonlinearities, which are enough to discriminate between one photon or two through a differential phase shift of 2 0 per photon. This new atom-photon interface may be used as a resource for processing quantum information.

An electrically driven cavity-enhanced source of indistinguishable photons with 61% overall efficiency

Directory of Open Access Journals (Sweden)

A. Schlehahn

2016-04-01

Full Text Available We report on an electrically driven efficient source of indistinguishable photons operated at pulse-repetition rates f up to 1.2 GHz. The quantum light source is based on a p-i-n-doped micropillar cavity with integrated self-organized quantum dots, which exploits cavity quantum electrodynamics effects in the weak coupling regime to enhance the emission of a single quantum emitter coupled to the cavity mode. We achieve an overall single-photon extraction efficiency of (61 ± 11 % for a device triggered electrically at f = 625 MHz. Analyzing the suppression of multi-photon emission events as a function of excitation repetition rate, we observe single-photon emission associated with g(2HBT(0 values between 0.076 and 0.227 for f ranging from 373 MHz to 1.2 GHz. Hong-Ou-Mandel-type two-photon interference experiments under pulsed current injection at 487 MHz reveal a photon-indistinguishability of (41.1 ± 9.5 % at a single-photon emission rate of (92 ± 23 MHz.

Towards Scalable Entangled Photon Sources with Self-Assembled InAs /GaAs Quantum Dots

Science.gov (United States)

Wang, Jianping; Gong, Ming; Guo, G.-C.; He, Lixin

2015-08-01

The biexciton cascade process in self-assembled quantum dots (QDs) provides an ideal system for realizing deterministic entangled photon-pair sources, which are essential to quantum information science. The entangled photon pairs have recently been generated in experiments after eliminating the fine-structure splitting (FSS) of excitons using a number of different methods. Thus far, however, QD-based sources of entangled photons have not been scalable because the wavelengths of QDs differ from dot to dot. Here, we propose a wavelength-tunable entangled photon emitter mounted on a three-dimensional stressor, in which the FSS and exciton energy can be tuned independently, thereby enabling photon entanglement between dissimilar QDs. We confirm these results via atomistic pseudopotential calculations. This provides a first step towards future realization of scalable entangled photon generators for quantum information applications.

Klystron-modulator system availability of PLS 2 GeV electron linac

International Nuclear Information System (INIS)

Cho, M.H.; Park, S.S.; Oh, J.S.; Namkung, W.

1996-01-01

PLS Linac has been injecting 2 GeV electron beams to the Pohang Light Source (PLS) storage ring since September 1994. PLS 2 GeV linac employs 11 sets of high power klystron-modulator (K and M) system for the main RF source for the beam acceleration. The klystron has rated output peak power of 80 MW at 4 microsec pulse width and at 60 pps. The matching modulator has 200 MW peak output power. The total accumulated high voltage run time of the oldest unit has reached beyond 23,000 hour and the sum of all the high voltage run time is approximately 230,000 hour as of May 1996. In this paper, we review overall system performance of the high-power K and M system. A special attention is paid on the analysis of all failures and troubles of the K and M system which affected the linac high power RF operations as well as beam injection operations for the period of 1994 to May 1996. (author)

Room-Temperature Single-Photon Source for Secure Quantum Communication

Data.gov (United States)

National Aeronautics and Space Administration — We are asking for four years of support for PhD student Justin Winkler's work on a research project entitled "Room temperature single photon source for secure...

Event Registration System for INR Linac

International Nuclear Information System (INIS)

Grekhov, O.V.; Drugakov, A.N.; Kiselev, Yu.V.

2006-01-01

The software of the Event registration system for the linear accelerators is described. This system allows receiving of the information on changes of operating modes of the accelerator and supervising of hundreds of key parameters of various systems of the accelerator. The Event registration system consists of the source and listeners of events. The sources of events are subroutines built in existing ACS Linac. The listeners of events are software Supervisor and Client ERS. They are used for warning the operator about change controlled parameter of the accelerator

Sources of electron contamination for the Clinac-35 25-MV photon beam

International Nuclear Information System (INIS)

Petti, P.L.; Goodman, M.S.; Sisterson, J.M.; Biggs, P.J.; Gabriel, T.A.; Mohan, R.

1983-01-01

A detailed Monte Carlo approach has been employed to investigate the sources of electron contamination for the 25-MV photon beam generated by Varian's Clinac-35. Three sources of contamination were examined: (a) the flattening filter and beam monitor chamber, (b) the fixed primary collimators downstream from the monitor chamber and the adjustable photon jaws, and (c) the air volume separating the treatment head from the observation point. Five source-to-surface distances (SSDs) were considered for a single field size, 28 cm in diameter at 80 cm SSD. It was found that for small SSDs (80-100 cm), the dominant sources of electron contamination were the flattening filter and the beam monitor chamber which accounted for 70% of the unwanted electrons. Thirteen percent of the remaining electrons originated in the downstream primary collimators and the photon jaws, and 17% were produced in air. At larger SSDs, the fraction of unwanted electrons originating in air increased. At 400 cm SSD, 61% of the contaminating electrons present in the beam were produced in air, 34% originated in the flattening filter and beam monitor chamber, and 5% were due to interactions in the fixed collimators downstream from the monitor chamber and the adjustable photon jaws. These calculated results are substantiated by recent experiments

High Voltage Installation of PS Linac 1 Preinjector

CERN Multimedia

CERN PhotoLab

1974-01-01

The high-voltage installation of the linac 1 preinjector in its house-sized Faraday cage. Originally driven by a 520 kV Cockcroft-Walton generator, at the time of this picture the HV came from a 520 kV SAMES generator. The column in the front carries a capacitor. The cubicle in the right background is the electronics platform (see 7403120). The round structure at left houses the ion source, from where the protons (and sometimes other ions), electrostatically accelerated to 520 keV, enter the Alvarez structure of linac 1, to be accelerated to 50 MeV. Jean-Luc Vallet is busy with servicing the installation. See also 7403064X, 7403066X.

Photon spectrum and absorbed dose in brain tumor.

Science.gov (United States)

Vega-Carrillo, Hector Rene; Silva-Sanchez, Angeles; Rivera-Montalvo, Teodoro

2016-11-01

Using Monte Carlo methods a BOMAB phantom inside a treatment hall with a brain tumor nearby the pituitary gland was treated with photons produced by a Varian 6MV linac. The photon spectrum and the absorbed dose were calculated in the tumor, pituitary gland and the head. The treatment beam was collimated to illuminate only the tumor volume; however photons were noticed in the gland. Photon fluence reaching the tumor is and 15.7 times larger than the fluence in the pituitary gland, on the other hand the absorbed dose in the tumor is 37.1 times larger than the dose in the gland because photons that reach the pituitary gland are scattered, by the head and the tumor, through Compton effect. Copyright © 2016 Elsevier Ltd. All rights reserved.

Photon Science at Modern Light Sources

Science.gov (United States)

Arthur, John

2009-12-01

More than 50 large x-ray and UV light sources based on high-energy electron accelerators are in operation around the world, serving a scientific community numbering in the tens of thousands. These sources generate synchrotron radiation from accelerated electrons or positrons. The development of synchrotron light sources over the last 40 years has fueled an exponential increase in x-ray source brightness of more than 10 orders of magnitude. The next large advance in source potential is now underway, with the commissioning of the first x-ray Free-Electron Laser (FEL) sources. Using high-energy electron linear accelerators, these facilities produce sub-picosecond pulses of hard x-rays with peak brightness more than 10 orders of magnitude greater than current synchrotron facilities. FEL x-ray facilities will soon be operational in the US, Japan, and Germany. Research at modern light sources makes use of a wide range of experimental techniques. Many experiments are designed to study the structure of matter at the atomic scale using elastic x-ray scattering. This technique has been particularly effective for determining the structures of biological molecules, such as proteins, viruses, and drugs. Inelastic x-ray scattering, or x-ray absorption followed by emission of electrons or photons, can give information about the electronic structures of atoms, which can be used to deduce local environment information such as atomic species, bonding state, geometry of neighboring atoms, or magnetic state. For some techniques involving x-ray emission from a sample, cryogenic detectors with energy resolution at the ˜10 eV level or better would be very helpful. Shifts in electron energy levels associated with bonding states and magnetic states are typically several eV, while the energy structure associated with Compton inelastic scattering is typically in the range of a few tens of eV. Current energy-resolving detectors used at synchrotron light sources are hampered by either poor

Uncertainty and sensitivity analysis of the effect of the mean energy and FWHM of the initial electron fluence on the Bremsstrahlung photon spectra of linear accelerators

International Nuclear Information System (INIS)

Juste, B.; Miró, R.; Verdú, G.; Macián, R.

2012-01-01

A calculation of the correct dose in radiation therapy requires an accurate description of the radiation source because uncertainties in characterization of the linac photon spectrum are propagated through the dose calculations. Unfortunately, detailed knowledge of the initial electron beam parameters is not readily available, and many researchers adjust the initial electron fluence values by trial-and-error methods. The main goal of this work was to develop a methodology to characterize the fluence of initial electrons before they hit the tungsten target of an Elekta Precise medical linear accelerator. To this end, we used a Monte Carlo technique to analyze the influence of the characteristics of the initial electron beam on the distribution of absorbed dose from a 6 MV linac photon beam in a water phantom. The technique is based on calculations with Software for Uncertainty and Sensitivity Analysis (SUSA) and Monte Carlo simulations with the MCNP5 transport code. The free parameters used in the SUSA calculations were the mean energy and full-width-at-half-maximum (FWHM) of the initial electron distribution. A total of 93 combinations of these parameters gave initial electron fluence configurations. The electron spectra thus obtained were used in a simulation of the electron transport through the target of the linear accelerator, which produced different photon (Bremsstrahlung) spectra. The simulated photon spectra were compared with the 6-MV photon spectrum provided by the linac manufacturer (Elekta). This comparison revealed how the mean energy and FWHM of the initial electron fluence affect the spectrum of the generated photons. This study has made it possible to fine-tune the examined electron beam parameters to obtain the resulted absorbed doses with acceptable accuracy (error <1%). - Highlights: ► Mean energy and radial spread are important parameters for simulating the incident electron beam in radiation therapy. ► Errors in determining the electron

Photonuclear and Radiation Effects Testing with a Refurbished 20 MeV Medical Electron Linac

CERN Document Server

Webb, Timothy; Beezhold, Wendland; De Veaux, Linda C; Harmon, Frank; Petrisko, Jill E; Spaulding, Randy

2005-01-01

An S-band 20 MeV electron linear accelerator formerly used for medical applications has been recommissioned to provide a wide range of photonuclear activation studies as well as various radiation effects on biological and microelectronic systems. Four radiation effect applications involving the electron/photon beams are described. Photonuclear activation of a stable isotope of oxygen provides an active means of characterizing polymer degradation. Biological irradiations of microorganisms including bacteria were used to study total dose and dose rate effects on survivability and the adaptation of these organisms to repeated exposures. Microelectronic devices including bipolar junction transistors (BJTs) and diodes were irradiated to study photocurrent from these devices as a function of peak dose rate with comparisons to computer modeling results. In addition, the 20 MeV linac may easily be converted to a medium energy neutron source which has been used to study neutron damage effects on transistors.

25th anniversary for Linac-2

CERN Multimedia

2003-01-01

On Friday, 3 October 2003, the Linac team celebrated a quarter century of successful operation of one of its linear accelerators: Linac-2, the proton workhorse of the CERN accelerator complex. Linac-2, CERN's linear proton accelerator, has now been running for 25 years - ample reason for a small celebration. About 30 members of the original team (10 of the initially more than 50 are still working at CERN), and other CERN personnel met on 3 October 2003. Linac-2 is the first link in the accelerator chain Linac-2 - PS Booster - PS - SPS and eventually LHC. Beams from Linac-2 are used after further acceleration in the CERN complex for SPS fixed target physics; for antiproton production for the Antiproton Decelerator (AD); for test beams in the East Experimental Hall and in the PS; for nuclear physics at ISOLDE; for LHC test beams and in the past for both ISR physics and Antiproton production (AA/AC) and test beams in LEAR. Linac-2 was built to obtain higher intensities and better stability than with ...

A Monte Carlo multiple source model applied to radiosurgery narrow photon beams

International Nuclear Information System (INIS)

Chaves, A.; Lopes, M.C.; Alves, C.C.; Oliveira, C.; Peralta, L.; Rodrigues, P.; Trindade, A.

2004-01-01

Monte Carlo (MC) methods are nowadays often used in the field of radiotherapy. Through successive steps, radiation fields are simulated, producing source Phase Space Data (PSD) that enable a dose calculation with good accuracy. Narrow photon beams used in radiosurgery can also be simulated by MC codes. However, the poor efficiency in simulating these narrow photon beams produces PSD whose quality prevents calculating dose with the required accuracy. To overcome this difficulty, a multiple source model was developed that enhances the quality of the reconstructed PSD, reducing also the time and storage capacities. This multiple source model was based on the full MC simulation, performed with the MC code MCNP4C, of the Siemens Mevatron KD2 (6 MV mode) linear accelerator head and additional collimators. The full simulation allowed the characterization of the particles coming from the accelerator head and from the additional collimators that shape the narrow photon beams used in radiosurgery treatments. Eight relevant photon virtual sources were identified from the full characterization analysis. Spatial and energy distributions were stored in histograms for the virtual sources representing the accelerator head components and the additional collimators. The photon directions were calculated for virtual sources representing the accelerator head components whereas, for the virtual sources representing the additional collimators, they were recorded into histograms. All these histograms were included in the MC code, DPM code and using a sampling procedure that reconstructed the PSDs, dose distributions were calculated in a water phantom divided in 20000 voxels of 1x1x5 mm 3 . The model accurately calculates dose distributions in the water phantom for all the additional collimators; for depth dose curves, associated errors at 2σ were lower than 2.5% until a depth of 202.5 mm for all the additional collimators and for profiles at various depths, deviations between measured

Workshop: Linac90

Energy Technology Data Exchange (ETDEWEB)

Van Dyck, Olin

1990-12-15

In 1960 the first linear accelerator (linac) conference was organized at Brookhaven by John Blewett. In the few years following, linear accelerator energies jumped from 50 MeV (at Brookhaven and CERN) to 2 GeV at Stanford. With the realization that, at least for electrons, circular accelerators have reached their practical limits, linacs are once more in the spotlight.

Workshop: Linac90

International Nuclear Information System (INIS)

Van Dyck, Olin

1990-01-01

In 1960 the first linear accelerator (linac) conference was organized at Brookhaven by John Blewett. In the few years following, linear accelerator energies jumped from 50 MeV (at Brookhaven and CERN) to 2 GeV at Stanford. With the realization that, at least for electrons, circular accelerators have reached their practical limits, linacs are once more in the spotlight

Boosting up quantum key distribution by learning statistics of practical single-photon sources

International Nuclear Information System (INIS)

Adachi, Yoritoshi; Yamamoto, Takashi; Koashi, Masato; Imoto, Nobuyuki

2009-01-01

We propose a simple quantum-key-distribution (QKD) scheme for practical single-photon sources (SPSs), which works even with a moderate suppression of the second-order correlation g (2) of the source. The scheme utilizes a passive preparation of a decoy state by monitoring a fraction of the signal via an additional beam splitter and a detector at the sender's side to monitor photon-number splitting attacks. We show that the achievable distance increases with the precision with which the sub-Poissonian tendency is confirmed in higher photon-number distribution of the source, rather than with actual suppression of the multiphoton emission events. We present an example of the secure key generation rate in the case of a poor SPS with g (2) =0.19, in which no secure key is produced with the conventional QKD scheme, and show that learning the photon-number distribution up to several numbers is sufficient for achieving almost the same distance as that of an ideal SPS.

Research on backward traveling wave electron linac

International Nuclear Information System (INIS)

Chen Huaibi; Zheng Shuxin; Ding Xiaodong; Lin Yuzheng

1999-01-01

Future electron linacs require high gradient acceleration. The studies on the high shunt impedance backward traveling wave electron linac accelerating structure (BTW) are presented. At first, the characteristics of BTW are researched. The option of mode and optimal design methods of accelerating cavity for BTW are studied. A physical design method for BTW accelerators, including longitudinal and transversal particle dynamics, is given. Based on above studies, a 9 MeV BTW accelerating tube at 3π/4 mode with frequency 2856 MHz for inspecting large container as radiation source at customs is designed, and a comparison with disk-loaded waveguide accelerating tube is made. The result of research leads to the conclusion that backward traveling wave accelerating structure is preferable. Because BTW has higher effective shunt impedance, shorter filling time and more stable operation

Improvement of the 400 kV linac electron source of AmPS

International Nuclear Information System (INIS)

Kroes, F.B.; Beuzekom, M.G. van; Dobbe, N.J.; Es, J.T. van; Jansweijer, P.P.M.; Kruijer, A.H.; Luigjes, G.; Sluijk, T.G.B.

1992-01-01

An existing linac (MEA) injects electrons into the Amsterdam Pulse Stretcher (AmPS) ring. The linac's peak current increases from 20 to 80 mA. This requires the modification of the 400 kV low emittance gun. The fourfold increase of the peak current is obtained by doubling both the gun perveance (new gun part) and the pulsed extractor voltage. To obtain optimum beam quality over this increased current range, the hot deck electronics has been exchanged by a fast high voltage FET switching supply. A built-in microprocessor, coupled to the local computer by optical fibers, is used to monitor and control the gun parameters. The 5 kV gun extractor voltage pulse shape can be monitored by means of an analog fibre transducer with build in calibration. Finally, in order to improve the energy stability of the accelerated electrons, a serial electron-tube stabilizer was added to the 400 kV DC power supply. (K.A.) 4 refs.; 6 figs

Soft x-ray spectroscopy undulator beamline at the Advanced Photon Source

Energy Technology Data Exchange (ETDEWEB)

Randall, K.J.; Xu, Z.; Moore, J.F.; Gluskin, E.

1997-09-01

Construction of the high-resolution soft x ray spectroscopy undulator beamline, 2ID-C, at the Advanced Photon Source (APS) has been completed. The beamline, one of two soft x ray beamlines at the APS, will cover the photon energy range from 500 to 3,000 eV, with a maximum resolving power between 7,000 and 14,000. The optical design is based on a spherical grating monochromator (SGM) giving both high resolution and high flux throughput. Photon flux is calculated to be approximately 10{sup 12}--10{sup 13} photons per second with a beam size of approximately 1 x 1 mm{sup 2} at the sample.

Injector linac of SPring-8

International Nuclear Information System (INIS)

Yoshikawa, H.; Hori, T.; Suzuki, S.; Yanagida, K.; Itoh, Y.; Mizuno, A.; Taniuchi, T.; Sakaki, H.; Kuba, A.; Fukushima, S.; Kobayashi, T.; Asaka, T.; Yokomizo, H.

1996-01-01

The linac that is SPring-8 injector was completed and started operation from August 1. A beam was able to be transported to the final beam dumping at a tail end on August 8. From now on this linac carries out beam adjustment and be scheduled to do a beam injection to a synchrotron in October. The construction and fundamental performance of the linac are described. (author)

Short wavelength FELs using the SLAC linac

International Nuclear Information System (INIS)

Winick, H.; Bane, K.; Boyce, R.

1993-08-01

Recent technological developments have opened the possibility to construct a device which we call a Linac Coherent Light Source (LCLS); a fourth generation light source, with brightness, coherence, and peak power far exceeding other sources. Operating on the principle of the free electron laser (FEL), the LCLS would extend the range of FEL operation to much aborter wavelength than the 240 mn that has so far been reached. We report the results of studies of the use of the SLAC linac to drive an LCLS at wavelengths from about 3-100 nm initially and possibly even shorter wavelengths in the future. Lasing would be achieved in a single pass of a low emittance, high peak current, high energy electron beam through a long undulator. Most present FELs use an optical cavity to build up the intensity of the light to achieve lasing action in a low gain oscillator configuration. By eliminating the optical cavity, which is difficult to make at short wavelengths, laser action can be extended to shorter wavelengths by Self-Amplified-Spontaneous-Emission (SASE), or by harmonic generation from a longer wavelength seed laser. Short wavelength, single pass lasers have been extensively studied at several laboratories and at recent workshops

Electron Linacs for High Energy Physics

International Nuclear Information System (INIS)

Wilson, Perry B.

2011-01-01

The purpose of this article is to introduce some of the basic physical principles underlying the operation of electron linear accelerators (electron linacs). Electron linacs have applications ranging from linacs with an energy of a few MeV, such that the electrons are approximately relativistic, to future electron-positron linear colliders having a collision energy in the several-TeV energy range. For the most part, only the main accelerating linac is treated in this article.

Free-Space Quantum Key Distribution with a High Generation Rate Potassium Titanyl Phosphate Waveguide Photon-Pair Source

Science.gov (United States)

Wilson, Jeffrey D.; Chaffee, Dalton W.; Wilson, Nathaniel C.; Lekki, John D.; Tokars, Roger P.; Pouch, John J.; Roberts, Tony D.; Battle, Philip; Floyd, Bertram M.; Lind, Alexander J.;

Status of the SNS superconducting linac and future plan

International Nuclear Information System (INIS)

Kim, Sang-Ho

2008-01-01

The use of superconducting radiofrequency (SRF) cavities in particle accelerator is becoming more widespread. Among the projects that make use of that technology is the Spallation Neutron Source, where H- ions are accelerated to about 1 GeV, mostly making use of niobium elliptical cavities. SNS generates neutrons by the spallation reaction with the accelerated short (about 700 ns) sub-bunches of protons, which will in turn allow probing structural and magnetic properties of new and existing materials. The SNS superconducting linac is the largest application of RF superconductivity to come on-line in the last decade and has been operating with beam for almost two years. As the first operational pulsed superconducting linac, many of the aspects of its performance were unknown and unpredictable. A lot of experiences and data have been gathered on the pulsed behavior of cavities and cryomodules at various repetition rates and at various temperatures during the commissioning of its components and beam operations. This experience is of great value in determining future optimizations of SNS as well in guiding in the design and operation of future pulsed superconducting linacs. The testing of the superconducting cavities, the operating experience with beam, the performance of the superconducting linac and the future plans will be presented.

Status of the advanced photon source

International Nuclear Information System (INIS)

Galayda, J.

1996-01-01

This report presents general information on the Advanced Photon Source (APS) and then breaks down the APS project into three categories: accelerator systems, experimental facilities, and conventional facilities. The accelerator systems consist of the 7 GeV APS positron storage ring and a 7 GeV positron injector. The experimental facilities include 20 undulator radiation sources and the x-ray beamline components necessary to transport their extraordinarily intense x-ray beams outside the accelerator enclosure. Also included are x-ray beamline components for 20 bending magnet radiation sources. The conventional facilities consist of the accelerator enclosures, a 35,300 m 2 experimental hall to house the x-ray beamlines, an office building for the APS staff and lab/office facilities for the research groups which will construct and operate the first 40 beamlines. APS users are described, and the properties of synchrotron radiation are discussed

Status report on the Advanced Photon Source, Spring 1990

International Nuclear Information System (INIS)

Moncton, D.E.

1990-01-01

The Advanced Photon Source (APS) at Argonne National Laboratory has been designed as a national user facility for synchrotron-radiation researchers from industry, universities, and national laboratories. In fact, the APS user community has been an important source of guidance and expertise throughout the project's planning cycle. By providing x-ray beams more brilliant than those currently available, the APS promises to play a substantial role in any discipline where knowledge of the structure of matter is important, from basic research in materials and chemistry to condensed-matter physics, biology, and medical applications. The science now in progress at existing synchrotron-radiation facilities, and the science being proposed for the APS, underlie virtually all modern technologies. In February of 1986, a conceptual design report (CDR) was issued detailing plans for a next-generation synchrotron-radiation machine, the 6-GeV Synchrotron X-ray Source. In April of 1987, a second CDR formalized the design of the 7-GeV Advanced Photon Source. That design has been refined and carried forward to its current level of construction readiness. On the eve of ground-breaking ceremonies, a review of APS status is appropriate

Performance of the Advanced Photon Source

International Nuclear Information System (INIS)

Decker, G.

1997-01-01

The Advanced Photon Source (APS) positron storage ring is a 100-mA, 7-GeV, third-generation x-ray synchrotron radiation source which began operation in March 1995. Since that time, significant progress on beamline construction and commissioning has taken place, with many of the x-ray user beamlines in operation. Operational design goals which have been met or exceeded include 10-hour lifetime, > 90% availability, > 100-mA average current, > 5-mA single-bunch current, < 10% uncorrected coupling, 8-mm full vertical apertures for insertion devices, and ultra-stable orbit (<4.5 microm rms vertically, 17 microm horizontally). Progress beyond these design goals and a report on development plans, including top-up operation (injection with x-ray beamline shutters open), are presented

Bright single photon source based on self-aligned quantum dot–cavity systems

DEFF Research Database (Denmark)

Maier, Sebastian; Gold, Peter; Forchel, Alfred

2014-01-01

We report on a quasi-planar quantum-dot-based single-photon source that shows an unprecedented high extraction efficiency of 42% without complex photonic resonator geometries or post-growth nanofabrication. This very high efficiency originates from the coupling of the photons emitted by a quantum...... dot to a Gaussian shaped nanohill defect that naturally arises during epitaxial growth in a self-aligned manner. We investigate the morphology of these defects and characterize the photonic operation mechanism. Our results show that these naturally arising coupled quantum dot-defects provide a new...... avenue for efficient (up to 42% demonstrated) and pure (g2(0) value of 0.023) single-photon emission....

Insertion devices at the advanced photon source

International Nuclear Information System (INIS)

Moog, E.R.

1996-01-01

The insertion devices being installed at the Advanced Photon Source cause the stored particle beam to wiggle, emitting x-rays with each wiggle. These x-rays combine to make an intense beam of radiation. Both wiggler and undulator types of insertion devices are being installed; the characteristics of the radiation produced by these two types of insertion devices are discussed, along with the reasons for those characteristics

SU-G-BRB-04: Automated Output Factor Measurements Using Continuous Data Logging for Linac Commissioning

Energy Technology Data Exchange (ETDEWEB)

Zhu, X; Li, S; Zheng, D; Wang, S; Lei, Y; Zhang, M; Ma, R; Fan, Q; Wang, X; Li, X; Verma, V; Enke, C; Zhou, S [University of Nebraska Medical Center, Omaha, NE (United States)

2016-06-15

Purpose: Linac commissioning is a time consuming and labor intensive process, the streamline of which is highly desirable. In particular, manual measurement of output factors for a variety of field sizes and energy greatly hinders the commissioning efficiency. In this study, automated measurement of output factors was demonstrated as ‘one-click’ using data logging of an electrometer. Methods: Beams to be measured were created in the recording and verifying (R&V) system and configured for continuous delivery. An electrometer with an automatic data logging feature enabled continuous data collection for all fields without human intervention. The electrometer saved data into a spreadsheet every 0.5 seconds. A Matlab program was developed to analyze the excel data to monitor and check the data quality. Results: For each photon energy, output factors were measured for five configurations, including open field and four wedges. Each configuration includes 72 fields sizes, ranging from 4×4 to 20×30 cm{sup 2}. Using automation, it took 50 minutes to complete the measurement of 72 field sizes, in contrast to 80 minutes when using the manual approach. The automation avoided the necessity of redundant Linac status checks between fields as in the manual approach. In fact, the only limiting factor in such automation is Linac overheating. The data collection beams in the R&V system are reusable, and the simplified process is less error-prone. In addition, our Matlab program extracted the output factors faithfully from data logging, and the discrepancy between the automatic and manual measurement is within ±0.3%. For two separate automated measurements 30 days apart, consistency check shows a discrepancy within ±1% for 6MV photon with a 60 degree wedge. Conclusion: Automated output factor measurements can save time by 40% when compared with conventional manual approach. This work laid ground for further improvement for the automation of Linac commissioning.

SU-G-BRB-04: Automated Output Factor Measurements Using Continuous Data Logging for Linac Commissioning

International Nuclear Information System (INIS)

Zhu, X; Li, S; Zheng, D; Wang, S; Lei, Y; Zhang, M; Ma, R; Fan, Q; Wang, X; Li, X; Verma, V; Enke, C; Zhou, S

2016-01-01

Purpose: Linac commissioning is a time consuming and labor intensive process, the streamline of which is highly desirable. In particular, manual measurement of output factors for a variety of field sizes and energy greatly hinders the commissioning efficiency. In this study, automated measurement of output factors was demonstrated as ‘one-click’ using data logging of an electrometer. Methods: Beams to be measured were created in the recording and verifying (R&V) system and configured for continuous delivery. An electrometer with an automatic data logging feature enabled continuous data collection for all fields without human intervention. The electrometer saved data into a spreadsheet every 0.5 seconds. A Matlab program was developed to analyze the excel data to monitor and check the data quality. Results: For each photon energy, output factors were measured for five configurations, including open field and four wedges. Each configuration includes 72 fields sizes, ranging from 4×4 to 20×30 cm"2. Using automation, it took 50 minutes to complete the measurement of 72 field sizes, in contrast to 80 minutes when using the manual approach. The automation avoided the necessity of redundant Linac status checks between fields as in the manual approach. In fact, the only limiting factor in such automation is Linac overheating. The data collection beams in the R&V system are reusable, and the simplified process is less error-prone. In addition, our Matlab program extracted the output factors faithfully from data logging, and the discrepancy between the automatic and manual measurement is within ±0.3%. For two separate automated measurements 30 days apart, consistency check shows a discrepancy within ±1% for 6MV photon with a 60 degree wedge. Conclusion: Automated output factor measurements can save time by 40% when compared with conventional manual approach. This work laid ground for further improvement for the automation of Linac commissioning.

Numerical modeling of the Linac4 negative ion source extraction region by 3D PIC-MCC code ONIX

CERN Document Server

Mochalskyy, S; Minea, T; Lifschitz, AF; Schmitzer, C; Midttun, O; Steyaert, D

2013-01-01

At CERN, a high performance negative ion (NI) source is required for the 160 MeV H- linear accelerator Linac4. The source is planned to produce 80 mA of H- with an emittance of 0.25 mm mradN-RMS which is technically and scientifically very challenging. The optimization of the NI source requires a deep understanding of the underling physics concerning the production and extraction of the negative ions. The extraction mechanism from the negative ion source is complex involving a magnetic filter in order to cool down electrons’ temperature. The ONIX (Orsay Negative Ion eXtraction) code is used to address this problem. The ONIX is a selfconsistent 3D electrostatic code using Particles-in-Cell Monte Carlo Collisions (PIC-MCC) approach. It was written to handle the complex boundary conditions between plasma, source walls, and beam formation at the extraction hole. Both, the positive extraction potential (25kV) and the magnetic field map are taken from the experimental set-up, in construction at CERN. This contrib...

RF system developments for CW and/or long pulse linacs

International Nuclear Information System (INIS)

Lynch, M.

1998-01-01

High Power Proton Linacs are under development or proposed for development at Los Alamos and elsewhere. By current standards these linacs all require very large amounts of RF power. The Accelerator for Production of Tritium (APT) is a CW accelerator with an output current and energy of 100 mA and 1,700 MeV, respectively. The Spallation Neutron Source (SNS), in its ultimate configuration, is a pulsed accelerator with an average output power of 4 MW of beam. Other accelerators such as those that address transmutation and upgrades to LANSCE have similar requirements. For these high average power applications, the RF systems represent approximately half of the total cost of the linac and are thus key elements in the design and configuration of the accelerator. Los Alamos is fortunate to be actively working on both APT and SNS. For these programs the author is pursuing a number of component developments which are aimed at one or more of the key issues for large RF systems: technical performance, capital cost, reliability, and operating efficiency. This paper briefly describes some of the linac applications and then provides updates on the key RF developments being pursued

Review of superconducting linacs

International Nuclear Information System (INIS)

Bollinger, L.M.

1992-01-01

This paper summarizes the status of the technology of superconducting (SC) linacs designed for the acceleration of ions. The emphasis is on the technical issues involved, with only brief descriptions of the numerous linacs now in operation or under construction. Recent developments of special interest are treated in more detail, and remaining technical challenges are outlined. The technology required for acceleration of ions with velocity β ∼ 1 is not discussed because it is almost the same as for relativistic electrons. That is, this paper is mainly about SC linacs for low-velocity heavy ions. (Author) 5 tabs., 6 figs., 29 refs

Review of induction LINACS

International Nuclear Information System (INIS)

Faltens, A.; Keefe, D.

1981-10-01

There has been a recent upsurge of activity in the field of induction linacs, with several new machines becoming operational and others in the design stages. The performance levels of electron machines have reached 10's of kiloamps of current and will soon reach 10's of MeV's of energy. Acceleration of ion current has been demonstrated, and the study of a 10 GeV heavy ion induction linac for ICF continues. The operating principles of induction linacs are reviewed with the emphasis on design choices which are important for increasing the maximum beam currents

Review of induction linacs

International Nuclear Information System (INIS)

Faltens, A.; Keefe, D.

1982-01-01

There has been a recent upsurge of activity in the field of induction linacs, with several new machines becoming operational and others in the design stages. The performance levels of electron machines have reached 10's of kiloamps of current and will soon reach 10's of MeV's of energy. Acceleration of several kiloamps of ion current has been demonstrated, and the study of a 10 GeV heavy ion induction linac for ICF continues. The operating principles of induction linacs are reviewed with the emphasis on design choices which are important for increasing the maximum beam currents

Low-charge-state linac

Energy Technology Data Exchange (ETDEWEB)

Shepard, K.W.; Kim, J.W.

1995-08-01

A design is being developed for a low-charge-state linac suitable for injecting ATLAS with a low-charge-state, radioactive beam. Initial work indicates that the existing ATLAS interdigital superconducting accelerating structures, together with the superconducting quadrupole transverse focussing element discussed above, provides a basis for a high-performance low-charge-state linac. The initial 2 or 3 MV of such a linac could be based on a normally-conducting, low-frequency RFQ, possibly combined with 24-MHz superconducting interdigital structures. Beam dynamics studies of the whole low-charge-state post-accelerator section were carried out in early FY 1995.

Development of a Watt-level gamma-ray source based on high-repetition-rate inverse Compton scattering

Energy Technology Data Exchange (ETDEWEB)

Mihalcea, D.; Murokh, A.; Piot, P.; Ruan, J.

2017-07-01

A high-brilliance (~10²² photon s^-1 mm^-2 mrad^-2 /0.1%) gamma-ray source experiment is currently being planned at Fermilab (E_γ≃1.1 MeV). The source implements a high-repetition-rate inverse Compton scattering by colliding electron bunches formed in a ~300-MeV superconducting linac with a high-intensity laser pulse. This paper describes the design rationale along with some of technical challenges associated to producing high-repetition-rate collision. The expected performances of the gamma-ray source are also presented.

Proceedings of the fourth users meeting for the advanced photon source

Energy Technology Data Exchange (ETDEWEB)

1992-02-01

The Fourth Users Meeting for the Advanced Photon Source (APS) was held on May 7--8, 1991 at Argonne National Laboratory. Scientists and engineers from universities, industry, and national laboratories came to review the status of the facility and to look ahead to the types of forefront science that will be possible when the APS is completed. The presentations at the meeting included an overview of the project; critical issues for APS operation; advances in synchrotron radiation applications; users perspectives, and funding perspectives. The actions taken at the 1991 Business Meeting of the Advanced Photon Source Users Organization are also documented.

Proceedings of the fourth users meeting for the advanced photon source

International Nuclear Information System (INIS)

1992-02-01

The Fourth Users Meeting for the Advanced Photon Source (APS) was held on May 7--8, 1991 at Argonne National Laboratory. Scientists and engineers from universities, industry, and national laboratories came to review the status of the facility and to look ahead to the types of forefront science that will be possible when the APS is completed. The presentations at the meeting included an overview of the project; critical issues for APS operation; advances in synchrotron radiation applications; users perspectives, and funding perspectives. The actions taken at the 1991 Business Meeting of the Advanced Photon Source Users Organization are also documented

Single-Photon Source for Quantum Information Based on Single Dye Molecule Fluorescence in Liquid Crystal Host

International Nuclear Information System (INIS)

Lukishova, S.G.; Knox, R.P.; Freivald, P.; McNamara, A.; Boyd, R.W.; Stroud, Jr. C.R.; Schmid, A.W.; Marshall, K.L.

2006-01-01

This paper describes a new application for liquid crystals: quantum information technology. A deterministically polarized single-photon source that efficiently produces photons exhibiting antibunching is a pivotal hardware element in absolutely secure quantum communication. Planar-aligned nematic liquid crystal hosts deterministically align the single dye molecules which produce deterministically polarized single (antibunched) photons. In addition, 1-D photonic bandgap cholesteric liquid crystals will increase single-photon source efficiency. The experiments and challenges in the observation of deterministically polarized fluorescence from single dye molecules in planar-aligned glassy nematic-liquid-crystal oligomer as well as photon antibunching in glassy cholesteric oligomer are described for the first time

Space charge compensation on the low energy beam transport of Linac4

CERN Document Server

AUTHOR|(SzGeCERN)733270; Scrivens, Richard; Jesus Castillo, Santos

Part of the upgrade program in the injector chains of the CERN accelerator complex is the replacement of the the proton accelerator Linac2 for the brand new Linac4 which will accelerate H$^-$ and its main goal is to increase the beam intensity in the next sections of the LHC accelerator chain. The Linac4 is now under commissioning and will use several ion sources to produce high intensity unbunched H$^-$ beams with different properties, and the low energy beam transport (LEBT) is the system in charge of match all these different beams to the Radio frequency quadrupole (RFQ). The space charge forces that spread the beam ions apart of each other and cause emittance growth limits the maximum intensity that can be transported in the LEBT, but the space charge of intense unbunched ion beams can be compensated by the generated ions by the impact ionization of the residual gas, which creates a source of secondary particles inside the beam pipe. For negative ion beams, the effect of the beam electric field is to ex...

Acceleration characteristics of the injector Linacs for the Hyogo Hadrontherapy Center

International Nuclear Information System (INIS)

Inoue, J.; Sawada, K.; Sakata, T.

2000-01-01

Hyogo Hadrontherapy center in Harima Science Garden City is a cancer therapy facility with proton, helium and carbon beams. The beams are supplied by a synchrotron, which has manufactured by Mitsubishi Electric Corporation, with RF 1inacs as an injector, which has manufactured by Sumitomo Heavy Industries Ltd.(SHI). The injector consists of the identical ECR ion sources, a RFQ linac, and an Alvarez linac, which are connected by beam transport systems including vacuum systems, and some kinds of beam monitoring equipments. The results accomplished for the beam conditioning are described in this paper. (author)

Computation of Normal Conducting and Superconducting Linear Accelerator (LINAC) Availabilities

International Nuclear Information System (INIS)

Haire, M.J.

2000-01-01

A brief study was conducted to roughly estimate the availability of a superconducting (SC) linear accelerator (LINAC) as compared to a normal conducting (NC) one. Potentially, SC radio frequency cavities have substantial reserve capability, which allows them to compensate for failed cavities, thus increasing the availability of the overall LINAC. In the initial SC design, there is a klystron and associated equipment (e.g., power supply) for every cavity of an SC LINAC. On the other hand, a single klystron may service eight cavities in the NC LINAC. This study modeled that portion of the Spallation Neutron Source LINAC (between 200 and 1,000 MeV) that is initially proposed for conversion from NC to SC technology. Equipment common to both designs was not evaluated. Tabular fault-tree calculations and computer-event-driven simulation (EDS) computer computations were performed. The estimated gain in availability when using the SC option ranges from 3 to 13% under certain equipment and conditions and spatial separation requirements. The availability of an NC LINAC is estimated to be 83%. Tabular fault-tree calculations and computer EDS modeling gave the same 83% answer to within one-tenth of a percent for the NC case. Tabular fault-tree calculations of the availability of the SC LINAC (where a klystron and associated equipment drive a single cavity) give 97%, whereas EDS computer calculations give 96%, a disagreement of only 1%. This result may be somewhat fortuitous because of limitations of tabular fault-tree calculations. For example, tabular fault-tree calculations can not handle spatial effects (separation distance between failures), equipment network configurations, and some failure combinations. EDS computer modeling of various equipment configurations were examined. When there is a klystron and associated equipment for every cavity and adjacent cavity, failure can be tolerated and the SC availability was estimated to be 96%. SC availability decreased as

Heavy-ion-linac post-accelerators

International Nuclear Information System (INIS)

Bollinger, L.M.

1979-01-01

The main features of the tandem-linac system for heavy-ion acceleration are reviewed and illustrated in terms of the technology and performance of the superconducting heavy-ion energy booster at Argonne. This technology is compared briefly with the corresponding technologies of the superconducting linac at Stony Brook and the room-temperature linac at Heidelberg. The performance possibilities for the near-term future are illustrated in terms of the proposed extension of the Argonne booster to form ATLAS

Peripheral dose in photon beams from a linear accelerator with a multileaf collimator

International Nuclear Information System (INIS)

Lope Lope, R.; Lozano Flores, F.; Gracia Sorrosal, J.; Font Gomez, J.A.; Hernandez Vitoria, A.

2001-01-01

Radiation doses outside the radiotherapy treatment field are of radiation protection interest when anatomical structures with very low dose tolerances might be involved. One of the major sources of peripheral dose, scatter from secondary collimators, depends on the configuration of the collimator. In this study, peripheral dose was measured at two depths for 6 and 18 MV photons from a linac Primus (Siemens) with a multileaf collimator (MLC). Comparative measurements were made both with leaves and with the upper jaw positioned at the field edge near to the detector. Configuring the MLC leaves at the field edge yielded a reduction in peripheral dose. (author)

Exergetic analysis of refrigeration system of the Pelletron-Linac particle accelerator of the University of Sao Paulo

International Nuclear Information System (INIS)

Oliveira Filho, O.B. de

1993-01-01

The Pelletron-Linac accelerator of the University of Sao Paulo will use the existing electrostatic Pelletron accelerator as an injector for the linear superconducting accelerator (Linac), to increase the acceleration of the particles. The Linac uses a forced flow circulation helium system to promote continuous refrigeration for long periods of time, at temperatures below or equal to 4,9 K. This paper shows the exergetic analysis of the Pelletron-linac refrigerator, identifying the main sources of irreversibilities and evaluating energetic consumption of the system. An exergy-enthalpy diagram for the helium shows the thermodynamic processes that take place in the refrigeration plant and the exergy losses. (author)

Upgrading the Fermilab Linac local control system

International Nuclear Information System (INIS)

McCrory, E.S.; Goodwin, R.W.; Shea, M.F.

1991-02-01

A new control system for the Fermilab Linac is being designed, built and implemented. First, the nine-year-old linac control system is being replaced. Second, a control system for the new 805 MHz part of the linac is being built. The two systems are essentially identical, so that when the installations are complete, we will still have a single Linac Control System. 8 refs., 5 figs

Overview of the advanced photon source

International Nuclear Information System (INIS)

Moncton, D.E.; Crosbie, E.; Shenoy, G.K.

1989-01-01

The Advanced Photon Source planned for construction at Argonne National Laboratory is based on a low-emittance storage-ring operated at 7 GeV and capable of providing tunable undulator radiation from 4 to 40 keV (using the first and the third harmonics). A technical description of the accelerator facility and the storage ring is presented in this overview, along with a brief summary of the characteristics of radiation that will be available from the insertion devices. Various plans for user access to this national user facility are also given

Analytical description of photon beam phase spaces in inverse Compton scattering sources

Directory of Open Access Journals (Sweden)

C. Curatolo

2017-08-01

Full Text Available We revisit the description of inverse Compton scattering sources and the photon beams generated therein, emphasizing the behavior of their phase space density distributions and how they depend upon those of the two colliding beams of electrons and photons. The main objective is to provide practical formulas for bandwidth, spectral density, brilliance, which are valid in general for any value of the recoil factor, i.e. both in the Thomson regime of negligible electron recoil, and in the deep Compton recoil dominated region, which is of interest for gamma-gamma colliders and Compton sources for the production of multi-GeV photon beams. We adopt a description based on the center of mass reference system of the electron-photon collision, in order to underline the role of the electron recoil and how it controls the relativistic Doppler/boost effect in various regimes. Using the center of mass reference frame greatly simplifies the treatment, allowing us to derive simple formulas expressed in terms of rms momenta of the two colliding beams (emittance, energy spread, etc. and the collimation angle in the laboratory system. Comparisons with Monte Carlo simulations of inverse Compton scattering in various scenarios are presented, showing very good agreement with the analytical formulas: in particular we find that the bandwidth dependence on the electron beam emittance, of paramount importance in Thomson regime, as it limits the amount of focusing imparted to the electron beam, becomes much less sensitive in deep Compton regime, allowing a stronger focusing of the electron beam to enhance luminosity without loss of mono-chromaticity. A similar effect occurs concerning the bandwidth dependence on the frequency spread of the incident photons: in deep recoil regime the bandwidth comes out to be much less dependent on the frequency spread. The set of formulas here derived are very helpful in designing inverse Compton sources in diverse regimes, giving a

Drift Tube Linac Conditioning of Tank1

CERN Document Server

Shafqat, N; Toor, W A

2014-01-01

Tank1 of the Drift Tube Linac (DTL) of the Linac4 has been conditioned at the Linac4 tunnel. The tank was tuned for resonance at 352.2 MHz, and stable operation has been achieved with 725 µs long RF pulses at a repetition rate of 1 Hz. The maximum RF level that has been reached is 810 kW with a pulse width of 600 µs. Since this was the first RF structure exclusively conditioned in the Linac4 tunnel with the operation and control software of Linac4, some related issues and limitations had to be taken into account.

Photon beam commissioning of an Elekta Synergy linear accelerator

Science.gov (United States)

Al Mashud, Md Abdullah; Tariquzzaman, M.; Jahangir Alam, M.; Zakaria, GA

2017-12-01

The aim of this study is to present the results of commissioning of Elekta Synergy linear accelerator (linac). The acceptance test and commissioning were performed for three photon beams energies 4 MV, 6 MV and 15 MV and for the multileaf collimator (MLC). The percent depth doses (PDDs), in-plane and cross-plane beam profiles, head scatter factors (Sc), relative photon output factors (Scp), universal wedge transmission factor and MLC transmission factors were measured. The size of gantry, collimator, and couch isocenter were also measured.

A novel electron gun for inline MRI-linac configurations

International Nuclear Information System (INIS)

Constantin, Dragoş E.; Fahrig, Rebecca; Holloway, Lois; Keall, Paul J.

2014-01-01

Purpose: This work introduces a new electron gun geometry capable of robust functioning in the presence of a high strength external magnetic field for axisymmetric magnetic resonance imaging (MRI)-linac configurations. This allows an inline MRI-linac to operate without the need to isolate the linear accelerator (linac) using a magnetic shield. This MRI-linac integration approach not only leaves the magnet homogeneity unchanged but also provides the linac flexibility to move along the magnet axis of symmetry if the source to target distance needs to be adjusted. Methods: Simple electron gun geometry modifications of a Varian 600C electron gun are considered and solved in the presence of an external magnetic field in order to determine a set of design principles for the new geometry. Based on these results, a new gun geometry is proposed and optimized in the fringe field of a 0.5 T open bore MRI magnet (GE Signa SP). A computer model for the 6 MeV Varian 600C linac is used to determine the capture efficiency of the new electron gun-linac system in the presence of the fringe field of the same MRI scanner. The behavior of the new electron gun plus the linac system is also studied in the fringe fields of two other magnets, a 1.0 T prototype open bore magnet and a 1.5 T GE Conquest scanner. Results: Simple geometrical modifications of the original electron gun geometry do not provide feasible solutions. However, these tests show that a smaller transverse cathode diameter with a flat surface and a slightly larger anode diameter could alleviate the current loss due to beam interactions with the anode in the presence of magnetic fields. Based on these findings, an initial geometry resembling a parallel plate capacitor with a hole in the anode is proposed. The optimization procedure finds a cathode-anode distance of 5 mm, a focusing electrode angle of 5°, and an anode drift tube length of 17.1 mm. Also, the linac can be displaced with ±15 cm along the axis of the 0.5 T

Cross correlations of quantum key distribution based on single-photon sources

International Nuclear Information System (INIS)

Dong Shuangli; Wang Xiaobo; Zhang Guofeng; Sun Jianhu; Zhang Fang; Xiao Liantuan; Jia Suotang

2009-01-01

We theoretically analyze the second-order correlation function in a quantum key distribution system with real single-photon sources. Based on single-event photon statistics, the influence of the modification caused by an eavesdropper's intervention and the effects of background signals on the cross correlations between authorized partners are presented. On this basis, we have shown a secure range of correlation against the intercept-resend attacks.

MBE-4: an induction linac experiment for heavy ion fusion

International Nuclear Information System (INIS)

Fessenden, T.J.; Avery, R.T.; Brodzik, D.A.

1986-06-01

The multiple-beam induction linac approach to a heavy ion fusion driver features continuous current amplification along the accelerator and a minimum of transverse beam manipulation from source to pellet. Current amplification and bunch length control require careful shaping of the accelerating voltages. This driver approach exploits developments in electron induction linac technology that have occurred within the last 15 years at LBL, LLNL and NBS. MBE-4 is a four beam induction linac that models much of the accelerator physics of the electrostatically focused section of a considerably longer induction accelerator. Four parallel Cs + beams are electrostatically focussed and will be accelerated from 200 keV to approximately one MeV when the experiment is complete in the spring of 1987. The current in each of the four beams will increase from 10 to 40 mA due to both increase in beam speed and shortening of the bunch length. Results of experiments with the injector and first eight accelerating gaps are presented

Thermionic RF Gun and Linac Pre-Injector for SPEAR3

Energy Technology Data Exchange (ETDEWEB)

Park, S.

2003-08-11

Preparations are underway to upgrade the Spear2 to the third generation light source. Installation of all the subsystems will start in April 2003. Although the Spear3 RF system is entirely different from the present form, the pre-injector gun/linac and booster synchrotron will remain the same even after the upgrade. The thermionic rf gun reliability and stability are to be improved to inject 500 mA of stored current in shortest possible time. When a top-up mode is enforced, where the stored beam decay is replenished to maintain the constant current and thus constant light intensity, the Spear3 will take injection every few minutes. In that case the gun, linac, and booster must stay on at all times. In this report we will describe some improvements made on the gun and linac in the recent past, as well as their present performance and future upgrade to be made.

Statistical simulations of machine errors for LINAC4

CERN Document Server

Baylac, M.; Froidefond, E.; Sargsyan, E.

2006-01-01

LINAC 4 is a normal conducting H- linac proposed at CERN to provide a higher proton flux to the CERN accelerator chain. It should replace the existing LINAC 2 as injector to the Proton Synchrotron Booster and can also operate in the future as the front end of the SPL, a 3.5 GeV Superconductingg Proton Linac. LINAC 4 consists of a Radio-Frequency Quadrupole, a chopper line, a Drift Tube Linac (DTL) and a Cell Coupled DTL all operating at 352 MHz and finally a Side Coupled Linac at 704 MHz. Beam dynamics was studied and optimized performing end-to-end simulations. This paper presents statistical simulations of machine errors which were performed in order to validate the proposed design.

Commissioning plans for SSC linac

International Nuclear Information System (INIS)

Hurd, J.W.; Aprile, R.L.; Chang, C.R.; Crist, C.E.; Cutler, R.I.; Funk, L.W.; Guy, F.W.; Leifeste, G.T.; Raparia, D.; Saadatmand, K.; Sethi, R.C.; Swenson, D.A.; Tooker, J.; Yao, C.G.

1992-01-01

Presented are the general description of the SSC linac and the plans for commissioning. Sections of the linac are installed, tested, and beam commissioned in a serial approach. A specialized set of diagnostics is used to characterize the beam through each section. In addition to the standard diagnostic set, plans call for the use of a bunch shape monitor and x-ray spectrometer. Streak camera and digital imaging diagnostics will be developed. The commissioning plan is folded into the general linac project schedule to show the relation between delivery, staging, installation, conditioning, and actual commissioning with beam. These plans form the basis for coordination between the various organizations responsible for different elements of the linac including the technical components, infrastructure, and temporary staging and operation facilities. (Author) 2 figs., 17 refs

Narrowband polarization entangled telecom photon pair source

OpenAIRE

Kaiser , Florian; Issautier , Amandine; Alibart , Olivier; Martin , Anthony; Tanzilli , Sébastien

2011-01-01

Contributed Talk; International audience; During the last decade, quantum entanglement has paved the way out to of the lab modern applications such as quantum computation and communication. Today, small scale quantum networks exist already, but they are limited to a few 100 km distance, due to intrinsic fiber transmission losses and non perfect detectors. These networks are typically established using photon pair sources based on spontaneous parametric down conversion (SPDC). Widely used enta...

APS [Advanced Photon Source] interests in PEP

International Nuclear Information System (INIS)

Moncton, D.E.; Shenoy, G.K.; Mills, D.M.

1987-11-01

As one of the very few high-energy electron storage rings in the world, potentially available for synchrotron radiation studies, PEP represents an opportunity to accomplish certain preconstruction R and D tasks relevant to the successful construction and operation of dedicated user facilities such as the Advanced Photon Source (APS) at Argonne. Three topical areas are discussed: Accelerator R and D, Insertion Devices (ID) R and D, and Beam Line Instrumentation R and D

Front end designs for the 7-GeV advanced photon source

International Nuclear Information System (INIS)

Shu, D.; Barraza, J.; Sanchez, T.; Nielsen, R.W.; Collins, J.T.; Kuzay, T.M.

1992-01-01

The conceptual designs for the insertion device (ID) and bending magnet (BM) front ends have been completed for the 7-GeV Advanced Photon Source (APS) under construction at Argonne National Laboratory. These designs satisfy the generic front end functions. However, the high power and high heat fluxes imposed by the X-ray sources of the 7-GeV APS have presented various design engineering challenges for the front end. Consideration of such challenges and their solutions have led to novel and advanced features including modularized systems, enhanced heat transfer concepts in the fixed mask and the photon shutter designs, a radiation safety philosophy based on multiple photon shutters for a fail-safe operation, a sub-micron resolution beam position monitor for beam monitoring and ring feedback information, and minimal beam filtering concepts to deliver maximized beam power and spectra to the experimenters. The criteria and special features of the front end design are discussed in this paper

The photon energy dependence of the alanine/EPR dosimetry system, an experimental investigation

International Nuclear Information System (INIS)

Bergstrand, E.S.; Hole, E.O.; Shortt, K.R.; Ross, C.K.

2002-01-01

The energy dependence of a dosimetry system based on electron paramagnetic resonance (EPR) spectroscopy of alanine has been studied to determine its suitability for use in dose verification for radiotherapy. A few experiments with high-energy photon irradiation of alanine have been reported in the literature. However, the reported results disagree whether the ratio of dose in alanine to dose in water is independent of the radiation energy or whether there is a small dependence for photon energies of relevance to radiotherapy. The concentration of free radicals in alanine is proportional to the absorbed dose in alanine over a wide dose range covering three decades. The relative number of radicals may be determined by examining the EPR spectrum, and hence it is possible to determine the dose with a system that has been calibrated using a known dose of 60 Co radiation. In the present work, irradiations of alanine dosimeters were performed at the National Research Council (NRC), in Ottawa, Canada. The radiation qualities investigated were 10, 20 and 30 MV x-rays using the NRC linac. For each radiation quality, 30 dosimeters were irradiated in a water phantom with a level of absorbed dose to water ranging from 10 to 50 Gy. For reference purposes, irradiations using the NRC 60 Co source were performed on more or less the same day as the irradiations at each specific linac quality. In all beams, the dose to water was measured using a graphite-walled NE2571 ionisation chamber that was originally calibrated by comparison with a sealed-water calorimeter. The alanine dosimeters were evaluated at the EPR laboratory at the University of Oslo, Norway, using an X-band Bruker ESP300E spectrometer with a rectangular double resonator. One of the resonators contained a Mn 2+ /MgO sample that was read after each dosimeter reading, in order to provide independence from short-term sensitivity fluctuations in the spectrometer. All dosimeters irradiated at one specific linac quality were

A single-source photon source model of a linear accelerator for Monte Carlo dose calculation.

Science.gov (United States)

Nwankwo, Obioma; Glatting, Gerhard; Wenz, Frederik; Fleckenstein, Jens

2017-01-01

To introduce a new method of deriving a virtual source model (VSM) of a linear accelerator photon beam from a phase space file (PSF) for Monte Carlo (MC) dose calculation. A PSF of a 6 MV photon beam was generated by simulating the interactions of primary electrons with the relevant geometries of a Synergy linear accelerator (Elekta AB, Stockholm, Sweden) and recording the particles that reach a plane 16 cm downstream the electron source. Probability distribution functions (PDFs) for particle positions and energies were derived from the analysis of the PSF. These PDFs were implemented in the VSM using inverse transform sampling. To model particle directions, the phase space plane was divided into a regular square grid. Each element of the grid corresponds to an area of 1 mm2 in the phase space plane. The average direction cosines, Pearson correlation coefficient (PCC) between photon energies and their direction cosines, as well as the PCC between the direction cosines were calculated for each grid element. Weighted polynomial surfaces were then fitted to these 2D data. The weights are used to correct for heteroscedasticity across the phase space bins. The directions of the particles created by the VSM were calculated from these fitted functions. The VSM was validated against the PSF by comparing the doses calculated by the two methods for different square field sizes. The comparisons were performed with profile and gamma analyses. The doses calculated with the PSF and VSM agree to within 3% /1 mm (>95% pixel pass rate) for the evaluated fields. A new method of deriving a virtual photon source model of a linear accelerator from a PSF file for MC dose calculation was developed. Validation results show that the doses calculated with the VSM and the PSF agree to within 3% /1 mm.

A single-source photon source model of a linear accelerator for Monte Carlo dose calculation.

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Obioma Nwankwo

Full Text Available To introduce a new method of deriving a virtual source model (VSM of a linear accelerator photon beam from a phase space file (PSF for Monte Carlo (MC dose calculation.A PSF of a 6 MV photon beam was generated by simulating the interactions of primary electrons with the relevant geometries of a Synergy linear accelerator (Elekta AB, Stockholm, Sweden and recording the particles that reach a plane 16 cm downstream the electron source. Probability distribution functions (PDFs for particle positions and energies were derived from the analysis of the PSF. These PDFs were implemented in the VSM using inverse transform sampling. To model particle directions, the phase space plane was divided into a regular square grid. Each element of the grid corresponds to an area of 1 mm2 in the phase space plane. The average direction cosines, Pearson correlation coefficient (PCC between photon energies and their direction cosines, as well as the PCC between the direction cosines were calculated for each grid element. Weighted polynomial surfaces were then fitted to these 2D data. The weights are used to correct for heteroscedasticity across the phase space bins. The directions of the particles created by the VSM were calculated from these fitted functions. The VSM was validated against the PSF by comparing the doses calculated by the two methods for different square field sizes. The comparisons were performed with profile and gamma analyses.The doses calculated with the PSF and VSM agree to within 3% /1 mm (>95% pixel pass rate for the evaluated fields.A new method of deriving a virtual photon source model of a linear accelerator from a PSF file for MC dose calculation was developed. Validation results show that the doses calculated with the VSM and the PSF agree to within 3% /1 mm.

Production of Ac-225 for cancer therapy by photon-induced transmutation of Ra-226.

Science.gov (United States)

Melville, G; Meriarty, H; Metcalfe, P; Knittel, T; Allen, B J

2007-09-01

The increasing application of Ac-225 for cancer therapy indicates the potential need for its increased production and availability. The production of Ac-225 has been achieved using bremsstrahlung photons from an 18 MV medical linear accelerator (linac) to bombard a Ra-226 target. A linac dose of 2800 Gy produced about 64 microCi of Ra-225, which decays to Ac-225. This result, while consistent with the theoretical calculations, is far too low to be of practical use. A more powerful linac is required that runs at a higher current, longer pulse length and higher frequency for practical production. This process could also lead to the reduction of the nuclear waste product Ra-226.

Measurements of the Influence of Thermoplastic Mask in High Energy Photon Beams: Gel Dosimeter or Ionizing Chamber?

Science.gov (United States)

Moreira, M. V.; Petchevist, C. D.; de Almeida, A.

2009-12-01

The influence of the immobilization mask material on the absorbed dose distribution in patients exposed to radiotherapy treatment with photon beams has been investigated for photons from a 60Co source and a 6 MV Linac. Absorbed dose values have been inferred at different depths and in the build-up region. Dose measurements were obtained using Fricke Xylenol Gel dosimeter and the cylindrical PTW Freiburg TM 31016-0.016 cc ionizing micro chamber; their discrepancies are discussed. The affinities of FXG and PTW ICMicro for measurements with high energy photons and the difference in the effective atomic numbers due to their compositions are most likely the most important factors that contribute to the measured dose in the build-up region. The measured values show that the use of the mask material contributes to increase the absorbed doses near the surface of the tissue. The result also shows that the build-up effect for 60Co is significantly smaller than that for 6 MV photons; however, the variations noted in the final doses of the radiotherapic treatments with photons of high energy do not represent alterations in the total doses received by the patients submitted to the radiotherapy.

Vibration analysis of the photon shutter designed for the advanced photon source