124789806
INSTALLATION AND OPERATION OF THE BEAMLINES FOR THE 100-MeV PROTON LINAC
Beamlines and 100-MeV proton linac have been developed for 1st phase of KOMAC(Korea Multi-purpose Accelerator Complex) at the Gyeong-ju site. The linac supplies either 20-MeV or 100-MeV proton beams for beam applications. Each proton beam can be transported to 2 beamlines for industrial purpose and 3 beamlines for various researches. At the first phase, 2 beamlines were installed and under test.
126282229
STATUS OF 100-MeV PROTON LINAC DEVELOPMENT FOR PEFP
113201344
Design of Machine Protection System for the PEFP 100MeV Linac
125669672
OPERATION OF THE PEFP 20MEV PROTON LINAC AT KAERI
185078083
THE KOMAC ACCELERATOR FACILITY
The development of the KOMAC (Korea multi-purpose accelerator complex) accelerator facility was finished and will go into the operation period from July 2013. The facility consists of a 100-MeV proton linac including a 50-keV ion source, a 3-MeV RFQ (radio-frequency quadrupole), and a 100-MeV DTL, and 20-MeV and 100MeV beam lines. The linac and beam lines were developed by the Proton Engineering Frontier Project (PEFP), the first phase of KOMAC, from 2002 to 2012 [1]. The goal of the beam commissioning is delivering 100-MeV 1-kW proton beams to a beam bump in a 100MeV target room. After finishing the commissioning, the user beam service will start from July 2013. The KOMAC user facility consists of 2 beam lines in the initial operation stage and it will be increased to 10 beam lines in future. One beam line is for 20-MeV proton beams which are extracted after 20-MeV part of the DTL tanks. A medium energy beam transport (MEBT) is installed there for the 20-MeV beam extraction and the beam matching to the next DTL tank. The other beam line is for 100-MeV proton beams. This work summarized the status of the KOMAC accelerator and beam lines. KOMAC 100-MeV PROTON LINAC The KOMAC accelerator building consists of 3 stories. The first floor includes the linac tunnel, and 20-MeV and 100-MeV beam line halls. There is a klystron gallery in the second floor. The third one is the modulator room. The accelerator building is shown in Figure 1. The main parameter of the linac is summarized in Table 1. Figure 1: Accelerator building which includes the linac and beam lines. The injector of the KOMAC accelerator consists of a microwave ion source [2] with the extraction energy of 50keV, and a low energy beam transport (LEBT) for matching proton beams into the RFQ. The ion source can work in cw (continuous wave) and pulsed modes. The peak beam current is 20 mA. Figure 2 shows the injecotr which was installed and tested in the tunnel. The 20-MeV part of the linac consists of a 3-MeV RFQ and a 20-MeV DTL (drift tube linac) [3]. The peak beam current and the maximum beam duty are respectively 20 mA and 24%. The RFQ is a four vane type with the resonant coupling and dipole rods for field stabilization. The DTL includes four tanks which are driven by a klystron. The FFDD lattice was adopted for the 20-MeV DTL with pool-type quadrupole magnets. Figure 3 is the 3-MeV RFQ which was tested in the linac tunnel. Table 1: Parameters of KOMAC Linac
125989328
INSTALLATION OF 100-MEV PROTON LINAC FOR PEFP
The Proton Engineering Frontier Project (PEFP) [1] at Korea Atomic Energy Research Institute (KAERI) is developing a 100-MeV proton linac in order to supply 20MeV and 100-MeV proton beams to users for proton beam application. The linac consists of a 50-keV injector, a 3-MeV radio frequency quadrupole (RFQ) and a 100MeV drift tube linac (DTL). The operation of the 20-MeV part of linac at Daejeon site was finished on November 2011. It was disassembled and moved to the Gyeongju site for installation as a low energy part of the linac. We completed the fabrication and test of the accelerating structures. The installation of the proton linac started in December 2011 at the new project site. The user service is scheduled for 2013 through the beam commissioning in 2012. This work summarized the installation status of the proton linac.
113398368
Calabi-Yau Manifolds, Hermitian Yang-Mills Instantons, and Mirror Symmetry
We address the issue of why Calabi-Yau manifolds exist with a mirror pair. We observe that the irreducible spinor representation of the Lorentz group requires us to consider the vector spaces of two forms and four forms on an equal footing. The doubling of the two-form vector space due to the Hodge duality doubles the variety of six-dimensional spin manifolds. We explore how the doubling is related to the mirror symmetry of Calabi-Yau manifolds. Via the gauge theory formulation of six-dimensional Riemannian manifolds, we show that the curvature tensor of a Calabi-Yau manifold satisfies the Hermitian Yang-Mills equations on the Calabi-Yau manifold. Therefore, the mirror symmetry of Calabi-Yau manifolds can be recast as the mirror pair of Hermitian Yang-Mills instantons. We discuss the mirror symmetry from the gauge theory perspective.
15073869
Non-Supersymmetric Unattractors in Born-Infeld Black Holes
We investigate unattractor behavior in non-extremal black holes in Einstein-Born-Infeld-Dilaton theory of gravity in four-dimensional asymptotically flat spacetime. We obtain solutions which are non-singular near the horizon and dependent on the value of the dilaton field at the infinity, using perturbation method. It is shown that the value of the scalar field at the horizon is determined by its asymptotic value and the charges carried by the black hole. And we also find it is not true in general that the dilaton value at the horizon is a monotonically increasing function of the first coefficient of its series expansion in non-extremal Born-Infeld black holes.
11614231
Moduli flow and non-supersymmetric AdS attractors
We investigate the attractor mechanism in gauged supergravity in the presence of higher derivative terms. In particular, we discuss the attractor behavior of static black hole horizons in anti-de Sitter spacetime by using the effective potential approach as well as Sen's entropy function formalism. We use the holographic techniques to interpret the moduli flow as an RG flow towards the IR attractor horizon. We find that the holographic c-function obeys the expected properties and point out some subtleties in understanding attractors in AdS.