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The External Target Facility (ETF) has been constructed for reaction studies with high-energy secondary beams of several hundred MeV/u. The charged fragment detector system of ETF consists of a dipole magnet, tracking drift chambers, ionization chambers and plastic scintillators for particle identification (PID) via B ρ - Δ E-TOF method. The system is now ready for physics experiments. Before physics runs, it has been tested using 280 MeV/u 18O primary beam as well as the secondary beams produced by projectile fragmentation. The system used as a magnetic spectrometer has exhibited satisfying PID capability in identifying fragments ranging from nitrogen to beryllium.

A drift chamber array at the External Target Facility in HIRFL-CSR has been constructed for three-dimensional particle tracking in high-energy radioactive ion beam experiments. The design, readout, track reconstruction program and calibration procedures for the detector are described. The drift chamber array was tested in a 311 AMeV 40Ar beam experiment. The detector performance based on the measurements of the beam test is presented. A spatial resolution of 230 μ m is achieved.

Heavy-ion fusion reactions, such as 12 C+ 12 C, play crucial roles in stellar evolution and nucleosynthesis in massive stars . However, limited by the low cross section and large background, it is very challenging to study the reactions at stellar energies. We have developed a 1024-channel prototype TPC named MATE (Multi-purpose time projection chamber for nuclear AsTrophysical and Exotic beam experiments) to study these reactions at stellar energies. The design of our prototype TPC and its performance are described, and the preliminary results of a commissioning experiment for measuring the 12 C( 12 C, α 0 ) 20 Ne reaction at E cm = 3.0 MeV are presented. Perspectives of future experiments for the 12 C+ 12 C fusion cross section measurement are also provided.

A Compact Spectrometer for Heavy IoN Experiments (CSHINE) has been recently built for the studies of heavy ion reactions at intermediate energies. CSHINE consists of a Si-Si-CsI telescope array and a parallel plate avalanche counter (PPAC) array. Each telescope consists of a thin single-sided silicon strip detector and a thick double-sided silicon strip detector backed by a 3 × 3 CsI(Tl) crystal hodoscope . The thicknesses of the silicon detectors are optimized in order to identify various types of light charged particles in a wide energy range. PPAC is a large-area two-dimensional position-sensitive gas detector, which records fission fragments with the intrinsic efficiency of approximately 100% but filters out light charged particles at properly selected working conditions. In the phase-II run, four Si-Si-CsI telescopes and three PPACs have been installed and operated in the beam experiment with 25 MeV/u Kr+Pb reactions. Particle identification for isotopes from Hydrogen to Boron has been achieved with the Si-Si-CsI telescopes, while excellent timing and position resolution have been achieved with the PPACs.

A Secondary Electrons Profile Monitor (SEPM) is developed as part of the beam dose delivery system in a clinical gantry of the Heavy Ion Medical Machine (HIMM). With the purpose of less disturbance to the beam, a thin foil with a thickness of 0 . 7 μ m and an accelerating grid with a diameter of 15 μ m are employed to produce and accelerate the secondary electrons, and two microchannel plates (MCPs) are used to multiply the electrons. Providing the real-time information of beam size, position, flatness, and symmetry in front of the scanning magnet, the beam monitor features an active area of 989 mm 2 , beam intensities between 1.0 × 1 0 3 to 1.0 × 1 0 8 particles per pulse (ppp) and a wide range of beam energies. A prototype is tested at the horizontal treatment room of the HIMM. Using different beam positions, sizes, and energies of 12C 6 + beams, test experiments show that the beam monitor maintains good consistency with a Multi-Strip Ionization Chamber (MSIC). Compared to the MSIC, the SEPM shows a better signal-to-noise ratio (SNR) and higher sensitivity to the variation of the beam.

To obtain the angular distributions of 12C + 12C elastic scatterings with the incident energies of 200–400A MeV for the study of three-body forces, a detector system was constructed at second Radioactive Ion Beam Line in Lanzhou (RIBLL2) of Institute of Modern Physics (IMP). This system was composed of five plastic scintillation detectors with two read-outs for each detector, a Multi Wire Proportional Chamber (MWPC) and a 4×4 CsI(Tl) array. The 12C beam with the incident energy of 200A MeV on a natural carbon target was used to test this detector system. It is found that the plastic scintillation detector can give the good energy loss (ΔE) and time of flight (TOF) signals, it can also reflect the position information of scattered 12C events. MWPC can precisely provide the trajectories of scattered particles. This system has a very good particle identification ability and can clearly distinguish the scattered 12C particles from the fragments. It can be used for the study of the three-body forces effect for high energy heavy-ion scattering.

A multiple sampling ionization chamber used as a particle identification device for high energy heavy ions has been developed for the External Target Facility. The performance of this detector was tested with a 239Pu α source and RI beams. A Z resolution (FWHM) of 0.4–0.6 was achieved for nuclear fragments of 18O at 400 AMeV.

A method is presented for the measurement of differential cross-sections of heavy ion elastic scattering induced by Radioactive Ion Beams (RIBs) on the Radioactive Ion Beam Line in Lanzhou (RIBLL) at the Heavy-Ion Research Facility in Lanzhou (HIRFL). The disadvantages of broad beam profiles and limited intensities of the RIBs were overcome using large area detectors, two Parallel-Plate Avalanche Counters (PPACs), two double-sided silicon strip detector (DSSD) telescopes, incorporated with Monte Carlo simulations. The PPACs were used to determine the direction and position of the beam particles. The DSSD telescopes were used to measure scattered particles. Small corrections for the misalignment of detectors and the data normalization were made by assuming the pure Rutherford scattering at very forward angles. The method is suitable for the measurement of the cross-sections on heavy targets at low and intermediate energies, and it has been successfully applied to measure the angular distribution of elastic scattering of 7Be on Pb target at E lab = 17.9 MeV / u .

A BGO hodoscope was developed to detect intermediate mass fragments (IMF) emitted from the intermediate energy heavy ion collisions. It consists of 13 Δ E – E telescopes (Si–BGO). The responses of the BGO detector for charged particles and IMF were tested. The results indicate that charge resolution for helium, IMF and isotope resolution for hydrogen are achieved for this hodoscope. Some applications of this hodoscope are also described.

A BGO crystal (Bi4Ge3O12) as the E detector of ΔE-E for identification of reaction products has been used for detecting the charged particles emitting from the 25 MeV/u 40Ar induced reaction. The responses of the BGO crystal to various light charged particles were measured. A close-packed hexagonal array consisting of thirteen ΔE-E telescopes (Si-BGO) has been developed to detect the light charged particles interfering with each other in intermediate-energy heavy-ion induced reactions. Some applications of this telescope array are also described.