[en] Highlights: • Two single-frequency 140 GHz gyrotrons are planned to be repaired to restore the performance to a good state for EAST. • The gyrotrons will be upgraded to have the output capability of 0.6 MW/1 MW at 105 GHz/140 GHz. • The upgraded ECRH system will be used for future EAST experiments to explore the range of low q₉₅ and high β_N. The ECRH (Electron Cyclotron Resonance Heating) system was used in the EAST (Experimental Advanced Superconducting Tokamak) experiments for several years, and some good experimental results have been obtained. However, the performance of the gyrotrons is degraded and the ability to stabilize output RF (Radio Frequency) power is reduced. Two single-frequency 140 GHz gyrotrons are planned to be repaired in order to improve the performance of the gyrotrons. At the same time, some internal components of the gyrotrons (such as collectors, electron guns, mode conversion mirrors) will be upgraded to make the gyrotrons have the output capability of 0.6 MW/1 MW at 105 GHz/140 GHz. The MOUs (Matching Optical Units), transmission lines, the low voltage power supplies, the measurement and control system, and the water-cooling system also need to be modified for the dual-frequency operation of the new gyrotrons. The retrofitted design of the EAST ECRH system using dual-frequency gyrotrons is discussed in the paper. The upgraded ECRH system will be used for future EAST experiments to explore the range of low q₉₅ and high β_N, to study the steady-state operation mode for the future nuclear fusion power plants.

[en] The activated carbon prepared from gasified rice husk carbon by gasification power generation (or RHAC), has been researched as a promising electrode materials for supercapacitors. In this work, we show a simple one-step solvothermal synthesis of flower-like RHAC/NiCo₂S₄ composite nanomaterials by an in-situ growth. Moreover, the RHAC/NiCo₂S₄ electrode demonstrates a capacitance of 1680 Fg^-1 and 1118.4 Fg^-1 at current densities of 1 A g⁻¹ and 12 A g⁻¹, respectively, which has excellent Rate performance. In order to improve the energy density of the supercapacitor, the asymmetric supercapacitors were assembled by a RHAC/NiCo₂S₄ electrode and RHAC electrode. The asymmetric supercapacitor delivers super great properties with a specific capacitance of 133.3 F g⁻¹ at the current density of 0.2 A g⁻¹ and the energy density of 41.6 Wh Kg⁻¹ at the power density is 150 W kg⁻¹. Furthermore, the energy density was maintained 29.2 Wh Kg⁻¹ at a high power density of 1500 W kg⁻¹, demonstrating superior rate capability. Additionally, the asymmetric supercapacitor also exhibits better cycling stability with 86% capacitance retention at current density of 1 A g⁻¹ after 5000 cycles. In view of environment-friendly and well capacitance, such RHAC/NiCo₂S₄ electrode would hold a promising application as candidate materials in next-generation high-performance supercapacitor.

[en] A 140GHz electron cyclotron resonance heating and current drive (EC H and CD) project for EAST Tokamak is launched in 2011 with a total power of 4MW and pulse length of 100 s. The main objectives of the system are to provide central H and CD, assist start-up and control of MHD activities. The system comprises four gyrotrons each with nominal output power of 1MW at 140GHz. The RF power, transmitted through four evacuated corrugated waveguides will be injected into plasma from the low field side (radial port). The front steering equatorial launcher directs the RF beam over ±25° toroidally and scans over 38° poloidally. At present, the construction of the first 1MW system is undergoing for the expected campaign in the end of 2013. In this paper, the current status of the development and the design of the 140-GHz ECRH system are presented

[en] Micro-Raman analysis was used to identify the oxidation of a silicon microchannel plate (SiMCP) and it indicated that the bend phenomenon of the SiMCP was related to the release of stress and the volume expending of the silicon wall during the oxidation process. (paper)

[en] A long pulse electron cyclotron resonance heating (ECRH) system has been developed to meet the requirements of steady-state operation for the EAST superconducting tokamak, and the first EC wave was successfully injected into plasma during the 2015 spring campaign. The system is mainly composed of four 140 GHz gyrotron systems, 4 ITER-Like transmission lines, 4 independent channel launchers and corresponding power supplies, a water cooling, control and inter-lock system etc. Each gyrotron is expected to deliver a maximum power of 1 MW and be operated at 100-1000 s pulse lengths. The No.1 and No.2 gyrotron systems have been installed. In the initial commissioning, a series of parameters of 1 MW 1 s, 900 kW 10 s, 800 kW 95 s and 650 kW 753 s have been demonstrated successfully on the No.1 gyrotron system based on calorimetric dummy load measurements. Significant plasma heating and MHD instability suppression effects were observed in EAST experiments. In addition, high confinement (H-mode) discharges triggered by ECRH were obtained. (paper)

[en] Highlights: • The new constructing 140 GHz/1 MW/1000 s ECRH system was briefly introduced and the structure of ECRH launcher was detailedly described. • The transmission characteristics of the RF propagation inside the launcher were calculated and the Gaussian beam radius in the resonance layer of plasma was optimized. • Temperature distribution and thermal-stress of mobile mirror were analyzed. • The inner equivalent diameter of water channel in the mobile mirror and the suggested water velocity were analyzed. - Abstract: EAST is a medium sized superconducting tokamak with major radius R = 1.8 m, minor radius a = 0.45 m, plasma current I_p ≤ 1 MA, toroidal field B_T ≤ 3.5 T and expected plasma pulse length up to 1000 s. An electron cyclotron resonance heating (ECRH) launcher for four-beam injection is being installed on EAST tokamak. Four electron cyclotron wave beams which are generated from four sets of 140 GHz/1 MW/1000 s gyrotrons will be injected into the plasma by the spherical focusing mirrors and plane mobile mirrors. The focusing mirrors are spherical to focus Gaussian beams after reflection. Four plane mobile mirrors independently steer continuously in the poloidal and toroidal direction controlled by motors. With the suitable distance between mirrors and appropriate focal length of focusing mirror, the beam radius in the resonance layer of plasma is 31.145 mm. The heat from plasma radiation and metal losses is loaded on the mobile mirror. In order to decrease the temperature and thermal stress, the inner equivalent diameter of water channels is 8 mm and the suggested water velocity is 4 m/s

[en] Highlights: • The conceptual design of 170 GHz/20 MW electron cyclotron wave system was introduced. • The layout of RF sources was given. • The design and layout of transmission lines were shown and series of microwave components were introduced. • The structure of launcher was described in detail. • By the optic calculation and optimization of RF propagation inside the launcher, the quasi-optical parameters for launcher design were given. And then temperature distribution and thermal-stress of the injection mirror were analyzed. - Abstract: China Fusion Engineering Test Reactor (CFETR) is a test tokamak which is built for magnetically confined fusion plasma experiments. The electron cyclotron (EC) wave system of CFETR is designed to inject 20 MW RF power into the plasma for heating and current drive (H&CD) applications. The EC wave system consists of RF sources, twenty transmission lines (TLs) and one equatorial launcher. RF sources contain twenty gyrotrons with the output power 1 MW. There are series of microwave components distributed along the TL and the percentage of power losses of each TL is about 8.7%. In the equatorial launcher, five RF beams are injected into one focusing mirror and then reflected to the plasma via one injection mirror. The focusing mirror is spherical to focus Gaussian beam and the injection mirror which is flat can steer in the toroidal direction. After optic calculation and optimization, all the quasi-optical parameters for launcher design are given. Combining with the thermal stress analysis, the chosen inner diameter of water channel of injection mirror is 12 mm and the suggested water velocity is 3 m/s

[en] Highlights: • A new launcher mirror unit was developed based on adjusting the water cooling line layout and designing the detachable mirror. • In situ replacement the reflector of the launcher mirror inside the device could be realized with the new design. • The new launcher mirror employs a type of dot-matrix water cooling channel structure. • Temperature distribution and thermal-stress of the new mirror were analyzed by fluid-thermal-solid coupling analysis. Significant progress has been achieved on EAST tokamak with the electron cyclotron resonance heating (ECRH), but the maintenance current EC launcher is very complicated after each campaign period. In order to reduce the maintenance frequency and cut down the maintenance cost, a new launcher mirror unit was developed based on adjusting the water cooling pipe lines layout and designing the detachable mirror. It improves the bending conditions and extends the life of the metal hoses effectively. Meanwhile, in situ replacement of the mirror reflector inside the device could be realized with the new design. The new launcher mirror employs a type of dot-matrix water cooling channel structure. It is demonstrated that the cooling design satisfies ECRH operating requirement with lower mass flow by fluid-thermal-solid coupling analysis.

[en] To evaluate the clinical efficacy and toxicity of stereotactic body radiation therapy (SBRT) using extracranial gamma knife in patients with mainly bulky inoperable early stage non-small cell lung carcinoma (NSCLC). A total of 43 medically inoperable patients with mainly bulky Stage I/II NSCLC received SBRT using gamma knife were reviewed. The fraction dose and the total dose were determined by the radiation oncologist according to patients' general status, tumor location, tumor size and the relationship between tumor and nearby organ at risk (OAR). The total dose of 34~47.5 Gy was prescribed in 4~12 fractions, 3.5~10 Gy per fraction, one fraction per day or every other day. The therapeutic efficacy and toxicity were evaluated. The median follow-up was 22 months (range, 3-102 months). The local tumor response rate was 95.35%, with CR 18.60% (8/43) and PR 76.74% (33/43), respectively. The local control rates at 1, 2, 3, 5 years were 77.54%, 53.02%, 39.77%, and 15.46%, respectively, while the 1- and 2-year local control rates were 75% and 60% for tumor ≤3 cm; 84% and 71% for tumor sized 3~5 cm; 55% and 14.6% for tumor sized 5~7 cm; and 45%, 21% in those with tumor size of >7 cm. The overall survival rate at 1, 2, 3, 5 years were 92.04%, 78.04%, 62.76%, 42.61%, respectively. The toxicity of stereotactic radiation therapy was grade 1-2. Clinical stages were significantly important factor in local control of lung tumors (P = 0.000). Both clinical stages (P = 0.015) and chemotherapy (P = 0.042) were significantly important factors in overall survival of lung tumors. SBRT is an effective and safe therapy for medically inoperable patients with early stage NSCLC. Clinical stage was the significant prognostic factors for both local tumor control and overall survival. The toxicity is mild. The overall local control for bulky tumors is poor. Tumor size is a poor prognostic factor, and the patients for adjuvant chemotherapy need to be carefully selected

[en] The change in the toroidal rotation of plasma caused by electron cyclotron wave (ECW) injection has been observed in EAST. It is found that the response of the rotation is similar for all possible ECW toroidal injection angles. The core toroidal rotation velocity increases in the co-current direction along with a rise in the plasma temperature and stored energy. The profile of the electron temperature, ion temperature and toroidal rotation velocity gradually become peaked. The change in toroidal rotation in the core increases with the ECW injection power. Different behavior is observed when the ECWs are injected into low hybrid current drive (LHCD) target plasmas, where the electron temperature and rotation profile become peaked, while the ion temperature profile flattens after ECW injection, suggesting different transport characteristics in energy and momentum. (paper)