120454450
Einstein-Maxwell-Dilaton Black Branes with Arbitrary Tension and Dilaton Charge
In this note, we show that special choice of the metric ansatz simplifies the equations of motion for black branes. Then we use the trick to construct charged, dilatonic black branes of Einstein–Maxwell–dilaton gravity in D = n + p + 2 dimensions, which are invariant under translation along p directions and have spherical symmetry of Sn. The solutions are characterized by mass density and tension, magnetic charges, dilaton charge and coupling constant.
118397938
BRANE SOLUTIONS WITH TENSION
In this note, we apply a special metric ansatz to simplify the equations of motion for gravitational systems. Then we construct charged brane solutions in D = n+p+2 dimensions which have spherical symmetry of Sn and translational symmetry along p directions. They are characterized by mass density, uniform tension and electric/magnetic charges, and nonsingular only for specific tension. In particular, we find the limits and the coordinate transformations which reduce the charged brane solutions to M2- and M5-branes. We also obtain the regularity condition for an electrically charged two-brane solution which has two tensions.
118510404
Symmetry Breaking Phase Transitions in ABJM Theory with a Finite U(1) Chemical Potential
We consider the U(1) charged sector of ABJM theory at finite temperature, which corresponds to the Reissner-Nordstrom AdS black hole in the dual type IIA supergravity description. Including back-reaction to the bulk geometry, we show that phase transitions occur to a broken phase where SU(4) R-symmetry of the field theory is broken spontaneously by the condensation of dimension one or two operators. We construct the composite operators out of fields in ABJM theory and describe the phase transition with the dual gravity solutions. We show numerically and analytically that the relevant critical exponents for the dimension one operator agree precisely with those of mean field theory in the strongly coupled regime of the large N planar limit.
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.
118481681
Thermal aspects of the ABJM theory: currents and condensations
To study thermal aspects of the ABJM theory in the strongly coupled regime, we carry out the invariant dimensional reduction of the type IIA supergravity down to four dimensions. We then investigate zero and finite temperature responses of the operators which are dual to the AdS scalar and vector fields. Two scalar operators are shown to have finite-temperature condensations by coupling of the constant source term. The currents dual to the massless and massive gauge fields are not induced by coupling of the constant boundary vector potential, which implies that the phase described by the black brane background is not superconducting. We also discuss a generalization to charged (dyonic) black holes.
16002558
Higher derivative correction to Kaluza–Klein black hole solution
We investigate the attractor mechanism in a Kaluza–Klein black hole solution in the presence of higher derivative terms. In particular, we discuss the attractor behavior of static black holes by using the effective potential approach as well as the entropy function formalism. We consider different higher derivative terms with a general coupling to the moduli field. For the R2 theory, we use an effective potential approach, looking for solutions which are analytic near the horizon and showing that they exist and enjoy attractor behavior. The attractor point is determined by extremization of the modified effective potential at the horizon. We study the effect of the general higher derivative corrections of Rn terms. Using the entropy function we define the modified effective potential and we find the conditions to have the attractor solution. In particular for a single charged Kaluza–Klein black hole solution we show that a higher derivative correction dresses the singularity for an appropriate coupling, and we can find the attractor solution.
62888926
FIVE YEAR OPERATION OF THE 20-MeV PROTON ACCELERATOR AT KAERI*
A 20-MeV proton linear accelerator was operated since 2007 by Proton Engineering Frontier Project (PEFP) at Korea Atomic Energy Research Institute (KAERI), Daejeon site. The performance test of the accelerator itself has been done with limited operation conditions. In addition, the 20-MeV accelerator was used as a test bench of the 100-MeV accelerator components. Besides the machine study itself, it supplied proton beams to more than 1600 samples for users. The 20-MeV accelerator was disassembled at Nov. 2011 and installed at Gyeongju site as an injector for the 100-MeV linac in March 2012. In this paper, five year operation experiences of the 20-MeV linac at Daejeon site are summarized and the technical issues are discussed.
113201344
Design of Machine Protection System for the PEFP 100MeV Linac
37852911
Design of 100 MeV Proton Beam Irradiation Facility for the PEFP 100 MeV Linac
The Proton Engineering Frontier Project (PEFP) will install a 100-MeV proton linear accelerator at Gyeong-ju site. For the beam commissioning of 100 MeV proton linac, the two target rooms (TR 103, TR 23) will be prepared as a starter among 10 target room. To design the irradiation equipment in TR 103, we have investigated general propagation shape and spatial distribution of proton beam, when 100 MeV proton beam extracted from vacuum in the beam lines through beam window by Monte carlo method. On the basis of this result, we have designed beam irradiation components and their configuration. The beam irradiation facility consist of beam window, beam dump, support frame, sample support and beam current monitor. To minimize residual radioactivity induced by incident proton beam, the pure aluminum was selected as the material of beam dump and the aluminum alloy was selected as material of other irradiation equipment. This residual radioactivity of equipment was estimated by Monte carlo method. In this paper, the details of this irradiation equipment design are presented.
140083239
BEAM TESTS OF THE PEFP 20 MEV ACCELERATOR *
Proton Engineering Frontier Project (PEFP) 20MeV proton accelerator has been installed and tested at KAERI (Korea Atomic Energy Research Institute) site. After the radiation license was issued, some parts were modified to increase a peak beam current above 1mA. A proton injector composed of an ion source and a LEBT (Low Energy Beam Transport) was modified for better transmission rate through the LEBT. The field profile of the RFQ was measured to check the dipole field effect. In addition, beam loss was measured along the DTL to check and adjust the operating parameters. In this paper, the modifications of the 20MeV accelerator are summarized and the recent test results are presented.
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.