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.

title: A Monitor Having Lots of Functions for a Linac with Feedback
abstract: In our 20 Mev electron linear accelerator with feedback we use a detector in the feedback loop to observe a microwave envelope which includes a lot of information. Under the accelerator operating condition from the micro wave envelope we can monitor the frequency, power, phase and beam loading and calculate the attenuation constant, group velocity, filling time and the field multiplication factor. We can also observe some unstable phenomena.

title: Investigation of neutron spectrum emitted from 44 GeV 12C+Cu interactions with nuclear emulsion
abstract: The Energy Spectrum of fast neutrons produced in 44 GeV 12 C+Cu interactions has been measured and analysed with nuclear emulsion of 8 cm in length, 2.2 cm in width and 400 μm in thickness made in China Institute of Atomic Energy, Beijing, China. The irradiation of the emulsion was carried out at the accelerator SYNCHROPHASOTRON of the Joint Institute for Nuclear Research, Dubna, Russia. The neutron spectrum was obtained through measuring the recoil protons in emulsion and the track parameters of α particles from interactions of 12 C(n,n′)3α in emulsion. The experimental neutron spectrum was compared with the results of a Monte-Carlo calculation, which shows that the shapes of both neutron spectra are identical within the limits of their statistical accuracy.

title: Development of a high power 1.2 MW CW L-band klystron
abstract: 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.

title: Study of neutron generation from relativistic heavy ion interactions
abstract: Study has been carried out on neutron generation in the interactions of 44 and 18 GeV 12 C with Cu-and Pb-targets. The properties studied include, (1) Relative yields of secondary neutrons generated in 44 GeV versus in 18 GeV 12 C bombardment to Cu target and also to Pb target. The ratios of these are 2.12±0.19 and 2.04±0.15, respectively, which is nearly in consistence with but somewhat larger than the values of theoretical calculations for Cu target. (2) Relative yields of secondary neutrons produced in Pb target versus in Cu target. The ratios obtained are 2.54±0.20 and 2.56±0.20 for 44 GeV and 18 GeV, respectively. More neutrons are generated in Pb target than in Cu target.

title: Further evidences for enhanced nuclear cross-sections observed in 44 GeV carbon ion interactions with copper

title: Vacuum monitoring system of HLS storage ring
abstract: The vacuum monitoring system of Hefei Light Source (HLS) storage ring is a subsystem of the upgraded HLS control system, which is based upon EPICS. There are 6 Varian vacuum Multi-Gauges controllers around the storage ring of HLS to monitor the pressure of 15 positions. An Industrial PC is used as Input/Output Controller (IOC) and it connects the 6 Varian vacuum Multi-Gauge controllers with serial communication (RS485 mode). The pressure values are displayed in a PC with Linux, which is used as operator interface (OPI). The pressure values are archived in a database and some data analyses are also done.

title: JUNO: A Multi-Purpose LS-based Experiment
abstract: After the discovery of the non-zero neutrino mixing angle 13 by the Daya Bay experiment and confirmed soon by many others, the most pressing question of neutrino physics is the mass hierarchy. We propose a next generation reactor neutrino experiment using the liquid scintillator to precisely measure the reactor neutrino energy spectrum so to determine the neutrino mass hierarchy. This is a multi-purpose experiment, which can also measure precisely neutrino mixing parameters 122132, and study supernova neutrinos, geo-neutrinos, sterile neutrinos as well as solar and atmospheric neutrinos. This new experiment is now under preparation and its progress is reported here.

title: Development of thermionic-cathode RF electron gun at IHEP
abstract: A thermionic cathode RF electron gun has been developed at the Institute of High Energy Physics, Academia Sinica, China. The gun will accelerate and prebunch electrons emitted from a L/sub a/B/sub 6/ cathode using a high electric field in a resonant cavity. The gun was fabricated and tested, and used in the Beijing free-electron laser project. Results of experimental measurements of the injector performance of a prototype gun are also presented.<<ETX>>

title: Measurements of the reactions C-12 (electron-neutrino, e-) N-12 (g.s.) and C-12 (electron-neutrino, e-) N*-12

title: Excess RF power required for RF control of the Spallation Neutron Source (SNS) linac, a pulsed high-intensity superconducting proton accelerator
abstract: A high-intensity proton linac, such as that being planned for the SNS, requires accurate RF control of cavity fields for the entire pulse in order to avoid beam spill. The current design requirement for the SNS is RF field stability within /spl plusmn/0.5% and /spl plusmn/0.5/spl deg/. This RF control capability is achieved by the control electronics using the excess RF power to correct disturbances. To minimize the initial capital costs, the RF system is designed with 'just enough' RF power. All the usual disturbances exist, such as beam noise, klystron/HVPS noise, coupler imperfections, transport losses, turn-on and turn-off transients, etc. As a superconducting linac, there are added disturbances of large magnitude, including Lorentz detuning and microphonics. The effects of these disturbances and the power required to correct them are estimated, and the result shows that the highest power systems in the SNS have just enough margin, with little or no excess margin.