http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
A 12-MHz CW RFQ for the AEBL Project
D. L. Schrage,P. N. Ostroumov,A. Barcikowski,D. Fallin,A. A. Kolomiets 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.3
The Advanced Exotic Beam Laboratory (AEBL) at the Argonne National Laboratory (ANL) will provide a research facility for studies of nuclear phenomena by using beams of short-lived isotopes for research on the nature of nucleonic matter and the origin of the elements, for tests of the Standard Model, for applications in medicine and industry, and for other applied physics research. The proposed design of the AEBL driver linac evolved from the Rare Isotope Accelerator (RIA) project. The AEBL will be a CW linac capable of accelerating uranium ions up to 200 MeV/u and protons to 580 MeV with 400 kW beam power. The AEBL facility also includes a post-accelerator which is designed for acceleration of radioactive ions with charge-to-mass ratios in the range from 1/238 to 1/6. Very low charge-state ions can be most eciently bunched and accelerated by using normally-conducting radio-frequency quadrupole (RFQ) for the rst few MV of the post accelerator. A two-meter long, 12-MHz CW RFQ was designed, built, and tested in the late 1990s as the rst section of a three-section RFQ [18]. This RFQ achieved inter-electrode voltages of 110 kV CW (the peak surface eld was 15 MV/m) and accelerated beams with A/q as large as 132 (132Xe). The AEBL requires a similar RFQ for the post-acceleration of singly-charged unstable nuclides. Our plan is to replace the vanes of this RFQ with a design that incorporates a stronger focusing and that will achieve a higher peak surface eld (16 MV/m) at 82.2-kV inter-vane voltage. The objectives of this project are 1. to conrm the possibility of a low injection energy of 0.4 keV/u which signicantly reduces the voltage required for a high-voltage deck; 2. to test the highest possible peak surface eld on the RFQ electrodes designed for the lowest frequency of 12 MHz compared to existing RFQs worldwide; 3. to provide a technical base for the design of a post-accelerator for the future Advanced Exotic Beam Facility. At the present time, the design is complete, and the fabrication of the 12 MHz RFQ is scheduled to commence in October 2007 with testing planned in 2008. The physics and engineering design of the RFQ is discussed. The Advanced Exotic Beam Laboratory (AEBL) at the Argonne National Laboratory (ANL) will provide a research facility for studies of nuclear phenomena by using beams of short-lived isotopes for research on the nature of nucleonic matter and the origin of the elements, for tests of the Standard Model, for applications in medicine and industry, and for other applied physics research. The proposed design of the AEBL driver linac evolved from the Rare Isotope Accelerator (RIA) project. The AEBL will be a CW linac capable of accelerating uranium ions up to 200 MeV/u and protons to 580 MeV with 400 kW beam power. The AEBL facility also includes a post-accelerator which is designed for acceleration of radioactive ions with charge-to-mass ratios in the range from 1/238 to 1/6. Very low charge-state ions can be most eciently bunched and accelerated by using normally-conducting radio-frequency quadrupole (RFQ) for the rst few MV of the post accelerator. A two-meter long, 12-MHz CW RFQ was designed, built, and tested in the late 1990s as the rst section of a three-section RFQ [18]. This RFQ achieved inter-electrode voltages of 110 kV CW (the peak surface eld was 15 MV/m) and accelerated beams with A/q as large as 132 (132Xe). The AEBL requires a similar RFQ for the post-acceleration of singly-charged unstable nuclides. Our plan is to replace the vanes of this RFQ with a design that incorporates a stronger focusing and that will achieve a higher peak surface eld (16 MV/m) at 82.2-kV inter-vane voltage. The objectives of this project are 1. to conrm the possibility of a low injection energy of 0.4 keV/u which signicantly reduces the voltage required for a high-voltage deck; 2. to test the highest possible peak surface eld on the RFQ electrodes designed for the lowest frequency of 12 MHz compared to existing RFQs worldwide; 3. to provide a technical base for the design of a post-accelerator for the future Advanced Exotic Beam Facility. At the present time, the design is complete, and the fabrication of the 12 MHz RFQ is scheduled to commence in October 2007 with testing planned in 2008. The physics and engineering design of the RFQ is discussed.
The bursts of high energy events observed by the telescope array surface detector
Abbasi, R.U.,Abe, M.,Abu-Zayyad, T.,Allen, M.,Anderson, R.,Azuma, R.,Barcikowski, E.,Belz, J.W.,Bergman, D.R.,Blake, S.A.,Cady, R.,Cheon, B.G.,Chiba, J.,Chikawa, M.,Fujii, T.,Fukushima, M.,Goto, T.,Ha North-Holland 2017 Physics letters. Section A. Vol.381 No.32
The Telescope Array (TA) experiment is designed to detect air showers induced by ultra high energy cosmic rays. The TA ground Surface particle Detector (TASD) observed several short-time bursts of air shower like events. These bursts are not likely due to chance coincidence between single shower events. The expectation of chance coincidence is less than 10<SUP>-4</SUP> for five-year's observation. We checked the correlation between these bursts of events and lightning data, and found evidence for correlations in timing and position. Some features of the burst events are similar to those of a normal cosmic ray air shower, and some are not. On this paper, we report the observed bursts of air shower like events and their correlation with lightning.
Abbasi, R. U.,Abe, M.,Abu-Zayyad, T.,Allen, M.,Anderson, R.,Azuma, R.,Barcikowski, E.,Belz, J. W.,Bergman, D. R.,Blake, S. A.,Cady, R.,Chae, M. J.,Cheon, B. G.,Chiba, J.,Chikawa, M.,Cho, W. R.,Fujii, IOP Publishing 2014 ASTROPHYSICAL JOURNAL LETTERS - Vol.790 No.2
<P>We have searched for intermediate-scale anisotropy in the arrival directions of ultrahigh-energy cosmic rays with energies above 57 EeV in the northern sky using data collected over a 5 yr period by the surface detector of the Telescope Array experiment. We report on a cluster of events that we call the hotspot, found by oversampling using 20 degrees radius circles. The hotspot has a Li-Ma statistical significance of 5.1 sigma, and is centered at R. A. = 146 degrees 7, decl. = 43 degrees 2. The position of the hotspot is about 19 degrees off of the supergalactic plane. The probability of a cluster of events of 5.1 sigma significance, appearing by chance in an isotropic cosmic-ray sky, is estimated to be 3.7 x 10(-4) (3.4 sigma).</P>
A 57-MHz CW RFQ for the AEBL Project
D.L. Schrage,A. Barcikowski,A.A. Kolomiets,B. Rusthoven,B. Clifft,F. DePaola,G. Waldschmidt,J.W. Rathke,M. Bracken,N.E. Vinogradov,P.N. Ostroumov,S. Sharma,S.I. Sharamentov,T. Schultheiss,W. F. Toter 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.I
The Advanced Exotic Beam Laboratory (AEBL) at the Argonne National Laboratory (ANL) will provide a research facility for studies of nuclear phenomena by using beams of short-lived isotopes for research in the nature of nucleonic matter, the origin of the elements, tests of the Standard Model along with applications in medicine, industry, and other applied physics research. The proposed design of the AEBL driver linac evolved from the Rare Isotope Accelerator (RIA) project. It is a CW 850 MV linac capable of accelerating uranium ions up to 200 MeV/u and protons to 570 MeV with 400 kW beam power. The first section of the linac is a 57 MHz pseudo split coaxial CW Radio Frequency Quadrupole (RFQ) linac. This is followed by 221 superconducting cavities of various types. A section of the RFQ linac was fabricated and tested under R\&D funding for the RIA Project. This is the first section of the six-section, 392 cm RFQ linac. This paper describes the design, fabrication, and testing of this RFQ.
First upper limits on the radar cross section of cosmic-ray induced extensive air showers
Abbasi, R.U.,Abe, M.,Abou Bakr Othman, M.,Abu-Zayyad, T.,Allen, M.,Anderson, R.,Azuma, R.,Barcikowski, E.,Belz, J.W.,Bergman, D.R.,Besson, D.,Blake, S.A.,Byrne, M.,Cady, R.,Chae, M.J.,Cheon, B.G.,Chib North-Holland 2017 Astroparticle physics Vol.87 No.-
<P>TARA (Telescope Array Radar) is a cosmic ray radar detection experiment colocated with Telescope Array, the conventional surface scintillation detector (SD) and fluorescence telescope detector (FD) near Delta, Utah, U.S.A. The TARA detector combines a 40 kW, 54.1 MHz VHF transmitter and high-gain transmitting antenna which broadcasts the radar carrier over the SD array and within the FD field of view, towards a 250 MS/s DAQ receiver. TARA has been collecting data since 2013 with the primary goal of observing the radar signatures of extensive air showers (EAS). Simulations indicate that echoes are expected to be short in duration (similar to 10 mu s) and exhibit rapidly changing frequency, with rates on the order 1 MHz/mu s. The EAS radar cross-section (RCS) is currently unknown although it is the subject of over 70 years of speculation. A novel signal search technique is described in which the expected radar echo of a particular air shower is used as a matched filter template and compared to waveforms obtained by triggering the radar DAQ using the Telescope Array fluorescence detector. No evidence for the scattering of radio frequency radiation by EAS is obtained to date. We report the first quantitative RCS upper limits using EAS that triggered the Telescope Array Fluorescence Detector. (C) 2016 Elsevier B.V. All rights reserved.</P>
The hybrid energy spectrum of Telescope Array's Middle Drum Detector and surface array
Abbasi, R.U.,Abe, M.,Abu-Zayyad, T.,Allen, M.G.,Anderson, R.,Azuma, R.,Barcikowski, E.,Belz, J.W.,Bergman, D.R.,Blake, S.A.,Cady, R.,Chae, M.J.,Cheon, B.G.,Chiba, J.,Chikawa, M.,Cho, W.R.,Fujii, T.,Fu North-Holland ; Elsevier Science Ltd 2015 Astroparticle physics Vol.68 No.-
The Telescope Array experiment studies ultra high energy cosmic rays using a hybrid detector. Fluorescence telescopes measure the longitudinal development of the extensive air shower generated when a primary cosmic ray particle interacts with the atmosphere. Meanwhile, scintillator detectors measure the lateral distribution of secondary shower particles that hit the ground. The Middle Drum (MD) fluorescence telescope station consists of 14 telescopes from the High Resolution Fly's Eye (HiRes) experiment, providing a direct link back to the HiRes measurements. Using the scintillator detector data in conjunction with the telescope data improves the geometrical reconstruction of the showers significantly, and hence, provides a more accurate reconstruction of the energy of the primary particle. The Middle Drum hybrid spectrum is presented and compared to that measured by the Middle Drum station in monocular mode. Further, the hybrid data establishes a link between the Middle Drum data and the surface array. A comparison between the Middle Drum hybrid energy spectrum and scintillator Surface Detector (SD) spectrum is also shown.
Abbasi, R. U.,Abe, M.,Zayyad, T. Abu-,Allen, M.,Anderson, R.,Azuma, R.,Barcikowski, E.,Belz, J. W.,Bergman, D. R.,Blake, S. A.,Cady, R.,Chae, M. J.,Cheon, B. G.,Chiba, J.,Chikawa, M.,Cho, W. R.,Fujii, IOP Publishing 2015 The Astrophysical journal Vol.804 No.2
<P>We report on the search for steady point-like sources of neutral particles around 10(18) eV between 2008 and 2013 May with the scintillator SD of the Telescope Array experiment. We found overall no significant point-like excess above 0.5 EeV in the northern sky. Subsequently, we also searched for coincidence with the Fermi bright Galactic sources. No significant coincidence was found within the statistical uncertainty. Hence, we set an upper limit on the neutron flux that corresponds to an averaged flux of 0.07 km(-2) yr(-1) for E > 1 EeV in the northern sky at the 95% confidence level. This is the most stringent flux upper limit in a northern sky survey assuming point-like sources. The upper limit at the 95% confidence level on the neutron flux from Cygnus X-3 is also set to 0.2 km(-2) yr(-1) for E > 0.5 EeV. This is an order of magnitude lower than previous flux measurements.</P>
Abu-Zayyad, T.,Aida, R.,Allen, M.,Anderson, R.,Azuma, R.,Barcikowski, E.,Belz, J.W.,Bergman, D.R.,Blake, S.A.,Cady, R.,Cheon, B.G.,Chiba, J.,Chikawa, M.,Cho, E.J.,Cho, W.R.,Fujii, H.,Fujii, T.,Fukuda, North-Holland ; Elsevier Science Ltd 2013 Astroparticle physics Vol.48 No.-
We present a measurement of the energy spectrum of ultra-high-energy cosmic rays performed by the Telescope Array experiment using monocular observations from its two new FADC-based fluorescence detectors. After a short description of the experiment, we describe the data analysis and event reconstruction procedures. Since the aperture of the experiment must be calculated by Monte Carlo simulation, we describe this calculation and the comparisons of simulated and real data used to verify the validity of the aperture calculation. Finally, we present the energy spectrum calculated from the merged monocular data sets of the two FADC-based detectors, and also the combination of this merged spectrum with an independent, previously published monocular spectrum measurement performed by Telescope Array's third fluorescence detector [T. Abu-Zayyad et al., The energy spectrum of Telescope Array's middle drum detector and the direct comparison to the high resolution fly's eye experiment, Astroparticle Physics 39 (2012) 109-119, http://dx.doi.org/10.1016/j.astropartphys.2012.05.012, Available from: <arXiv:1202.5141>]. This combined spectrum corroborates the recently published Telescope Array surface detector spectrum [T. Abu-Zayyad, et al., The cosmic-ray energy spectrum observed with the surface detector of the Telescope Array experiment, ApJ 768 (2013) L1, http://dx.doi.org/10.1088/2041-8205/768/1/L1, Available from: <arXiv:1205.5067>] with independent systematic uncertainties.
Search for EeV protons of galactic origin
Abbasi, R.U.,Abe, M.,Abu-Zayyad, T.,Allen, M.,Azuma, R.,Barcikowski, E.,Belz, J.W.,Bergman, D.R.,Blake, S.A.,Cady, R.,Cheon, B.G.,Chiba, J.,Chikawa, M.,Fujii, T.,Fukushima, M.,Goto, T.,Hanlon, W.,Haya North-Holland 2017 Astroparticle physics Vol.86 No.-
<P>Cosmic rays in the energy range 10(18.0)-10(18.5) eV are thought to have a light, probably protonic, composition. To study their origin one can search for anisotropy in their arrival directions. Extragalactic cosmic rays should be isotropic, but galactic cosmic rays of this type should be seen mostly along the galactic plane, and there should be a shortage of events coming from directions near the galactic anticenter. This is due to the fact that, under the influence of the galactic magnetic field, the transition from ballistic to diffusive behavior is well advanced, and this qualitative picture persists over the whole energy range. Guided by models of the galactic magnetic field that indicate that the enhancement along the galactic plane should have a standard deviation of about 20 degrees in galactic latitude, and the deficit in the galactic anticenter direction should have a standard deviation of about 50 degrees in galactic longitude, we use the data of the Telescope Array surface detector in 10(18.0) to 10(18.5) eV energy range to search for these effects. The data are isotropic. Neither an enhancement along the galactic plane nor a deficit in the galactic anticenter direction is found. Using these data we place an upper limit on the fraction of EeV cosmic rays of galactic origin at 1.3% at 95% confidence level. Published by Elsevier B.V.</P>