One of our two methods for fast-neutron imaging with spectrometric capability is presented here. It is a neutron-counting technique based on a hydrogenous neutron converter coupled to Gaseous Electron Multipliers (GEM). The principles of the detection techniques and the optimization of the converter, electron amplification and the readout are described. Evaluation of the properties are derived from a experiment in a pulsed neutron beam of spectral distribution between 2 and 10 MeV.

We describe design and simulations of a fast beam chopper for the SARAF accelerator based on an RF deflector preceding the RFQ. The SARAF 176 MHz RFQ, takes a DC proton or deuteron beam and accelerates and bunches the beam to 1.5 MeV/u and bunches of 0.3 ns width (FWHM) every 5.5 ns respectively. The deflector acts on the DC beam and sweeps away all but one of the pre-accelerated (pre)-bunches prior to the actual bunching and acceleration in the RFQ. Simulations were performed for a fast beam chopper, where several deflection voltage pulsing schemes have been investigated. The simulations show effective chopping with alternating positive and negative HV applied to the deflector with a fast HV switch, where the beam is transmitted to the RFQ during the cross-over of the rise(fall) of the HV switching. The simulations show that we can obtain efficient deflection of unwanted bunches, with 60% transmission efficiency for the desired bunch. The present design is for a chopper that will provide 0.3 ns bunches with a repetition rate of ∼10 5 bunches/sec. Plans for a fast chopper with higher repetition rates of ∼ 10 6 Hz are discussed.

Two generations of a novel detector for high-resolution transmission imaging and spectrometry of fast-neutrons are presented. These devices are based on a hydrogenous fiber scintillator screen and single-or multiple-gated intensified camera systems (ICCD). This detector is designed for energy-selective neutron radiography with nanosecond-pulsed broad-energy (1-10 MeV) neutron beams. Utilizing the Time-of-Flight (TOF) method, such a detector is capable of simultaneously capturing several images, each at a different neutron energy (TOF). In addition, a gamma-ray image can also be simultaneously registered, allowing combined neutron/gamma inspection of objects. This permits combining the sensitivity of the fast-neutron resonance method to low-Z elements with that of gamma radiography to high-Z materials. KEYWORDS: Instrumentation and methods for time-of-flight (TOF) spectroscopy; Detection of contraband and drugs; Detection of explosives; Neutron radiography

Phase I of the SARAF superconducting RF linac is under operation at the Soreq Nuclear Research Center. The present status of Phase I main components is reported, as well as, the beam operation experience accumulated in 2013-2014. The latter include acceleration of a 2 mA and 1.6 mA CW proton beams at energies of 2 MeV and 3.9 MeV correspondingly and 1 mA pulsed, duty cycle of few %, deuteron beams up to 5.6 MeV. The recent experiments include operation of intense CW proton beams on the liquid lithium target.

No abstract