IHEP Beijing, Beijing
CSNS accelerator mainly consists of an H- linac and a proton rapid cycling synchrotron. It is designed to accelerate proton beam pulses to 1.6 GeV kinetic energy at 25 Hz repetition rate, striking a solid metal target to produce spallation neutrons. The accelerator is designed to deliver a beam power of 120 kW with the upgrade capability up to 500 kW, The CSNS accelerator is the first large-scale, high-power accelerator project to be constructed in China and thus we are facing a lot of challenges in some key technologies. A series of R&D for major prototypes have being conducted since 2006, including an H- ion source, DTL tank, RF power supply for the linac, injection/extraction magnets and its pulse power supplies, dipole and quadrupole prototype magnets in the ring and its power supplies, ferrite-loaded RF prototype cavity, ceramic vacuum chamber, control and some beam diagnostics. This paper will briefly introduce the design and R&D status of the CSNS accelerator.
TUB, Beijing
BNL, Upton, Long Island, New York
Funding: Supported by National Natural Science Foundation of China (No.10735050, No.10875070) and National Basic Research Program of China (973 Program)(No.2007CB815102)
Time-resolved MeV ultra-fast electron diffraction (UED) is a promising tool for studying of structural dynamics on the fundamental temporal and spatial scales of atomic motion. To reach the desired temporal and spatial resolutions, precise control and measurement of ultra-short, low emittance electron pulses are required. A MeV UED system based on an S-band photocathode RF gun is built and optimized at Tsinghua University. We present the experiment results here.
TUB, Beijing
IHEP Beijing, Beijing
CIAE, Beijing
ANL, Argonne
KEK, Tsukuba
Funding: Supported by the “985 Project” of the Minister of Education of China, CAS Bairen Init. (KJCX2-YW-N22), CAS Overseas Outstanding Youth Program, and the National Natural Science Foundation (10628510).
During the past decades, large-scale national neutron sources are developed in Asia, Europe, and USA. Complementing such efforts, compact hadron beam complexes and neutron sources intended for universities and industrial institutes are proposed and established. Responding to the demands in China for multidisciplinary researches and applications using pulsed neutrons and protons, hadron therapy and radiography, and accelerator-driven sub-critical reactor systems (ADS) for nuclear waste transmutation, we here propose a compact yet expandable accelerator complex based on a proton source, a 3 MeV RFQ linac, and a 22 MeV DTL linac. A Be target with solid methane and room-temperature water moderators serve 6 neutron stations for imaging/radiography, irradiation, SANS, engineering powder diffraction, instrumentation, and therapy. The proton platform serves multiple stations for bio-applications, fuel cell and nano-applications, and space irradiation and detection. A rapid cycling synchrotron subsequently accelerates the beam to up to 300 MeV for proton therapy and radiography. Following the DTL linac with a superconducting RF linac and a sub-critical reactor offers an ADS test facility.
TUB, Beijing
LBNL, Berkeley, California
Funding: Supported by National Natural Science Foundation of China (No.10775080)
An S-band RF deflecting cavity has been developed and applied for measuring the bunch length at Tsinghua Thomson-Scattering X-ray Source (TTX). This paper briefly introduces the 3-cell pi-mode standing-wave deflecting cavity and reports the recent experiments of the beam diagnostics for the photo-cathode RF gun, which produces electron bunches with RMS length around 1-ps. It is also observed that the bunches are lengthened while the total charge increases, showing the strong space charge effect at a low beam energy.
TUB, Beijing
Funding: Work supported by National Science Foundation of China (No. 10775079)
On the basis of an X-band 2MeV on-axis standing wave electron linear accelerator, a compact 4MeV/2.5MeV X-band accelerator is being developed at Tsinghua University for non-destructive testing. The single tube can deliver two kinds of x-rays, with dose rate of >100cGy/min@m at 4MeV or >50cGy/min@m at 2.5MeV. To suppress the nearby modes, the coupler is set in the middle of the long coupled cavity chain. The coupled circuit model is applied to analyze the RF characteristic and the dynamic is investigated by CAV code. The prototype has being machined and tuned at our laboratory.
jfhua@mail.tsinghua.edu.cn