Measurement of the Proton Beam Characteristics of Low-energy Accelerators

China JinPing underground Laboratory (CJPL) was established inside the tunnels piercing Jinping Mountain in Sichuan Province, China, which can provide an ideal environment for low background experiment. A new 400 kV accelerator, with high current based on an ECR source, will be placed at this underground laboratory for nuclear astrophysics experiment. The beam characteristics of this accelerator, like absolute energy, energy spread, and long-term energy stability, will be determined by several wellknown resonance and non-resonance reactions. Due to the new accelerator still being under construction, the resonance reaction of ²⁷Al(p, γ)²⁸Si and non-resonance ¹²C(p, γ)¹³N were studied at the 320 kV highvoltage platform in Institute Modern Physics of CAS in Lanzhou. The energy spread of proton beam is about 1.0 keV at proton energy E_p=224 keV and the long-term energy stability of proton beam is much better than 200 eV during 4 hours measurement.