Effect of the residual atmosphere pressure on collective acceleration of ions in the Luce diode

Prompt γ and neutron spectrometry of intense nanosecond ion bunches collectively accelerated in a Luce diode

“…Here we report our recent results on a selective γand ToF spectrometry of neutrons generated by ions collectively accelerated with a Luce diode mode of TEMP-4M accelerator which was mostly described in [4][5][6][7][8][9][10]. Usually, two types of dielectric anode inserts with a hole diameter of 12 mm were used: polyethylene 8 mm thick and h-BN 2-4 mm thick.…”

“…For instantaneous control of the number and energy of protons in individual bunches collectively accelerated in a Luce diode, a two-channel γ-spectrometer was proposed and experimentally studied [4], in which time-resolved determination of the energy and number of protons in different proton bunches in each shot is possible due to selective measurement by two fast organic detectors ( with a resolution time of about 2.5 ns and better) of different sizes, placed in lead shielding of different thicknesses (2 and 7 cm) of signals from instantaneous γ quanta with an energy of 429 keV (LE-γ detector) from the nuclear reaction 10 B(p,αγ) 7 Be and γ quanta with Eγ ≥ 2366 keV (HE-γ detector) from the 12 C(p,γ) 13 N and 11 B(p,γ) 12 C reactions excited in the B4C target. The ratio of the signals and their absolute values at the instants of time corresponding to the discharge of bunches of collectively accelerated protons onto the target determine the energy and number of protons in these bunches, respectively [4].…”

“…The ratio of the signals and their absolute values at the instants of time corresponding to the discharge of bunches of collectively accelerated protons onto the target determine the energy and number of protons in these bunches, respectively [4]. The calibration of the instantaneous γ-spectrometer of proton bunches is carried out by the radioactivity 7 Be and 13 N induced in the B4C plates [5]. The use of the γ-spectrometer in combination with a virtual cathode (VC) time-of-flight spectrometer emitting electrons along the normal to the axis of its motion, recorded by VCE1-VCE5 sensors, made it possible to prove that the VC and the main group of ions arrive at the target simultaneously.…”

“…The nToF spectrometer is calibrated by measuring the 11 C radioactivity induced in the refractory B4C targets. In this case, the energy and number of protons of the main group (450-800 keV) are also controlled by the induced activity of 7 Be and 13 N, and the number of 12 C [7] ions is also controlled by the activity of 18 F. The fractions of high-energy protons with energies of ~3.4 MeV during collective acceleration in the Luce diode vary quite widely from shot to shot, and on average over a series of 10 shots they were about 5•10 -5 part of the main group of protons (on average ~10 14 per shot). In the future, of interest for refining the spectrum of protons with energies above 1 MeV is the use of threshold reactions 55 Mn(p,n) 55 Fe (Eth = 1.03 MeV), 93 Nb(p,n) 93m Mo (1.2 MeV), 51 V(p,n) 51 Cr (1.565 MeV)) and 7 Li(p,n) 7 Be (1.88 MeV).…”

“…Such a configuration later received the common name "Luce diode", although some workers argue that the configuration was principally similar to the one used by Plyutto [3]. Our approach to studying the model of collective ion acceleration is to use nuclear analysis methods to diagnose ion bunches accelerated by a Luce diode operated in the same configuration of electrodes at moderate voltage values of about 250 kV [4][5][6][7][8][9][10]. At such voltages, on the one hand, accelerated ions are already capable of generating nuclear reactions in targets made of light elements, but, on the other hand, it is still possible to selectively excite the required analytical reactions and generate selective signals that can be unambiguously attributed to one or another group of accelerated protons and heavy ions (mainly 12 C ions).…”