105752539
The preliminary explanation of a new working model on 10GHz ECR2 source
A new working model and a new magnetic field configuration were employed on the 10GHz ECR2 source of the heavy ion research facility in Lanzhou(HIRFL). That resulted in an obvious enhancement of beam currents of ECR2 ion source, the beam current of Ar9+ increase from 125 e mu A to 320 e mu A, for Ar11+ ion beam increase from 40 e mu A to 80 e mu A. In this paper, primary analysis and explanation of this working model is presented, we will also discuss the action of low energy electrons in ECR plasma and get an important conclusion, which the low energy electrons injection is more effective in the extraction region of ECR ion sources.
219179959
COMMISSIONING OF IMP 14.5GHZ ECR ION SOURCE
A 14.5 GHz.~ew. ECR ion source has been designed and constructed for the upgraded injection beam line of HIRF1.. SFC(Heavy Ion ~esearch FaCility m Lanzhou, Sector Focus Cyclotron) so that eventually two ECR ion sources could be available on the line. The new ECR Ion source has a compact struClUre with a high magnetic mirror ratio and a long chamber. The maximum axial magnetic field on the axis is around 1.5Tesla and the bexapole field on the chamber wall is I.OTesla. The ion source is being tested on the test bench. The preliminary results are typically 100 eJ1A of 0 7+, 160 eJ1A of Arll+ and 50 eJ1A of Xe26+. The design points, characteristics and commissioning are presented .
117148962
Population study for gama-ray emitting Millisecond Pulsars and Fermi unidentified sources
The $Fermi$-LAT has revealed that rotation powered millisecond pulsars (MSPs) are a major contributor to the Galactic $\gamma$-ray source population. We discuss the $\gamma$-ray emission process within the context of the outer gap accelerator model, and use a Monte-Calro method to simulate the Galactic population of the $\gamma$-ray emitting MSPs. We find that the outer gap accelerator controlled by the magnetic pair-creation process is preferable in explaining the possible correlation between the $\gamma$-ray luminosity and the spin down power. Our Monte-Calro simulation implies that most of the $\gamma$-ray emitting MSPs are radio quiet in the present sensitivity of the radio survey, indicating that most of the $\gamma$-ray MSPs have been unidentified. We argue that the Galactic $Fermi$ unidentified sources located at high latitudes should be dominated by MSPs, whereas the sources in the galactic plane are dominated by radio-quiet canonical pulsars.
6846086
PLANS FOR A 2 ND INSERTION DEVICE IN CAMD
To allow the possible installation of a 2 nd Insertion Device in the CAMD Light Source, the lattice optic needs to be changed. The present configuration has a small vertical beta function in the long straight section containing the 7 Tesla wiggler. The new optic will give a small vertical beta at two long straight sections which are diametrically opposite. Test results with the new optic are presented together with the measured beam parameters. These data are used to predict the photon beam performance for an Insertion Device which could be installed. nd generation facility of moderate brightness using a 4 cell Chasman-Green lattice. The normal beam operating energy is 1.3 GeV. At the injection energy of 200 MeV the lattice is operated in a fully symmetric zero dispersion mode, which is also used during the energy ramp. In 1998 a 3 pole wavelength shifter (3) was installed whose maximum field is 7 Tesla. This is used to provide hard X-rays for ultra-deep lithography, protein crystallography and other hard X-ray science. To increase the brightness, after the energy ramp is completed the optic is changed to one with finite dispersion in the long straights. This reduces the natural horizontal emittance by about a factor of 2 to 150 nm.rads. In addition the optic is configured to produce a small value of the vertical beta function at the center of the wiggler in order to increase the flux density of the source point. This is known as the minibeta optic.(4) The wavelength shifter is located in one of the 4 long straights which each have a free length of about 2.5 m. One of these straights contains the injection septum magnet and another contains the single RF cavity. The remaining straight is not presently used. These features may be seen in fig 1 which is a diagram of the CAMD facility. To enable the lattice to operate in the minibeta configuration, the F and D quadrupoles in the wavelength shifter straight are connected to independent power supplies. In addition these quadrupoles are adjusted to compensate for the focusing effects of the wavelength shifter and so maintain the beta values close to the optimum minibeta. At the end of the energy ramp the settings for the minibeta are applied smoothly in synchronism as the wavelength shifter is energized without loss of beam current.
110807481
Development of a high power 1.2 MW CW L-band klystron
The high power CW L-band klystron has been developed as the RF source of the PNC high power CW electron linac (10 MeV, 100 mA). CW power of 1.2 MW at 1.249135 GHz and efficiencies over 65% were the design goals. RF analysis of the windows using high-frequency simulation codes provided information about power loss distribution in the ceramic and optimizing properties of the RF structure. The prototype klystron window was replaced with a long pill-box type beryllia window as a result of the simulation and hardware tests. The klystron has reached CW power of 885 kW with efficiency above 45%. This paper describes key points of the designs and results of the high power RF tests.
41167320
Status of the CAMD Light Source
In parallel with the increasing diversity of its research program, the CAMD Light Source has improved its beam brightness and quality. Using a well calibrated model of the lattice, the ring optic has been refined to generate a lower beam emittance of 150 nm. rad and this has been confirmed by measuring the beta values with the modulated quadrupole shunt system. The beam sizes have also been measured with an X-ray pinhole camera and compared to the calculated emittance. The beam orbit is corrected to a standard position referenced to the quadrupole centers to a precision better than 0.5 mm, using a suite of well localized bumps which can also flexibly steer the user photon beams to their requirements. Beam reliability has been improved by bringing into use a VME control system for the energy ramp.
41894778
Initial results from the ANITA 2006-2007 Balloon Flight
We report initial results of the Antarctic Impulsive Transient Antenna (ANITA) 2006-2007 Long Duration Balloon flight, which searched for evidence of the flux of cosmogenic neutrinos. ANITA flew for 35 days looking for radio impulses that might be due to the Askaryan effect in neutrino-induced electromagnetic showers within the Antarctic ice sheets. In our initial high-threshold robust analysis, no neutrino candidates are seen, with no physics background. In a non-signal horizontal-polarization channel, we do detect 6 events consistent with radio impulses from extensive air showers, which helps to validate the effectiveness of our method. Upper limits derived from our analysis now begin to eliminate the highest cosmogenic neutrino models.