The design and characteristics of position sensitive detectors implemented in the form of a matrix of individual detectors (modules) with selective registration of electrons and protons are examined. It is proposed that such detectors be used as a basis for considering the possibility of building introscopes with a coded aperture for detecting images of sources of mixed fast-neutron and γ-radiation. Scintillation detectors with digital identification of neutrons and γ-rays according to the pulse shape or Cherenkov detectors registering only electrons (high-energy protons) are used as modular detectors. The registration of analogue pulses of detectors and their conversion into a digital form and subsequent digital processing are performed simultaneously, in parallel, and independently. This is optimal for increasing speed of operation and the loading of the modular scintillation detector to 10 6 counts/sec in the energy range 0.2–15 MeV for neutron radiation, 0.015–7 MeV for γ-radiation, and to 2∙10 8 counts/sec for Cherenkov radiation.

Описан метод измерения спектральных и временных характеристик импульсных смешанных (n, )-полей. Суть метода – последовательность сигналов c (n, )-детекторов от отдельных (n, )-частиц записывается в компьютер с последующим амплитудно-временным анализом параметров сигналов. В качестве (n, )-детекторов используются быстрые сцинтилляционные и черенковские детекторы с полушириной импульсов 1.5 нс и 2.5 нс соответственно. Запись и передача сигналов в компьютер осуществляются с помощью широкополосного цифрового осциллографа TDS-3054 через интерфейс GPIB-USB. Используемая аппаратура обеспечивает эффективную регистрацию (n, )-частиц при загрузках детекторов до 2 · 108 импульсов/c. Эффективность метода апробирована при измерениях характеристик полей (n, )-излучения от импульсного нейтронного генератора ИНГ-031 и из медной мишени, облучаемой пучком ядер углерода с энергией 200 МэВ/а.е.м. ускорительно-накопительного комплекса ТВН-ИТЭФ.

A method for measuring spectral and time characteristics of pulsed mixed ( n, γ ) fields is described. The essence of this method is that a sequence of signals from individual ( n, γ ) particles registered by ( n, γ ) detectors is written in a computer with the subsequent amplitude-time analysis of the signal parameters. Fast scintillation and Cherenkov detectors with FWHM of pulses of ∼1.5 and 2.5 ns, respectively, are used as ( n, γ ) detectors. A TDS-3054 broadband digital oscilloscope records signals and transmits them to the computer through a GPIB-USB interface. The equipment used ensures efficient detection of ( n, γ ) particles at detector counting rates of up to ∼2 × 10 8 pulses/s. The efficiency of this method has been tested in measurements of characteristics of ( n, γ ) radiation fields from an ИНГ-031 pulsed neutron generator and from a copper target irradiated with a beam of carbon nuclei with an energy of 200 MeV/amu from the TVN-ITEF acceleration-storage complex.

A digital method for pulse-shape discrimination between neutrons and γ rays was used in measurements at counting rates of up to ∼106 counts/s in the energy range of ∼2–800 keV. Pulses produced by neutrons and γ rays in a stilbene-based scintillation detector were digitized by a digital oscilloscope and transmitted to a computer for carrying out particle identification. Identification was performed for radiation of radionuclide sources and a pulsed neutron generator operating in a repeated triggering mode. Amplitude spectra of pulses identified as neutrons and γ rays of radiation from the generator were measured. At a detector counting rate of ∼8.5 × 105 counts/s, ∼90% of all recorded pulses were recognized as neutrons. In the energy range of ∼30–800 keV, the γ-ray suppression factor was ∼104–103 at counting rates of ∼1.5×105–5 × 105 counts/s, while the efficiency of identifying neutrons was >0.9. The suppression factor for γ rays with an energy of ∼10 keV was ∼300, and the neutron identification efficiency was ∼0.75.

The paper presents the first experimental results obtained by using new gamma-quantum diagnostics for ion beam induced high energy density matter. Registration of γ-quantum output from the region of beam-target interaction with time resolution enables to pick-up information on density evolution of the target even if the ionization state of matter involved is unknown.

Several laboratories in the world have started or plan to build new powerful ion accelerators. These facilities promise to provide very valuable tools for experiments in fundamental nuclear physics, physics of high energy density in matter and for medical applications as well. One of the most important problems that have to be solved during the design stage is the radiation protection of the accelerator. Due to the complexity it is hardly possible to obtain reliable radionuclide production data for accelerator structure materials from radiation transport codes. Thus, the experimental data which can be measured at the presently existing facilities (SIS-18, Ganil) are necessary for the evaluation of the induced levels of radioactivity around intense heavy ion accelerators. Results of the measurement of activation induced by Argon beam with energies of E = 300, 500, 800 MeV/u in the copper target are presented in this paper. MOTIVATION In recent years, requirements from new technological and research applications for particle accelerators have emerged, giving rise to new radiation shielding aspects and problems. For the new high-power accelerators currently being designed, activation of the accelerator structure has become an important issue. The main emphasis of new heavy ion accelerator projects (SIS-100, TWAC or future HIDIF) focuses on the technical developments needed to increase the achievable beam intensities by up to two orders of magnitude. The activation, however, produced by accelerators of such high power, has not yet been quantified. Hence, novel safety aspects evolving from the increased radioactive inventory of such facilities will obviously play the major role in the design and approval procedure. The experimental investigation of potential radiation risks during normal heavy ion accelerator operation is proposed in a new GSI-INTAS project. Three main topics that have to be investigated in this direction are as follows: 1. Characterization of radiation from selected components of the beam line, especially from the extraction section: production rates of radioactive nuclides