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—This article discusses the results of parallel measurements with two-coordinate position-sensitive He3 detectors with a delay line, which are installed on REFLEX and GRAINS neutron spectrometers of the IBR-2 pulsed reactor with the simultaneous use of three data acquisition systems: DeLiDAQ-1, DeLiDAQ-2, and a system based on the N6730 digitizer produced by CAEN.

Three neutron instruments at the Neutron Physics Laboratory (NPL) in Řež near Prague — small-angle scattering (SANS) MAUD, strain scanner SPN-100 and strain diffractometer TKSN-400 — have been modernized recently with new 2D position-sensitive detectors (PSDs) from JINR, Dubna. Here we report on the progress made in relation to the possibilities of the diffractometers due to the improved performance of the detectors. The first part of the paper is dedicated to a detailed description of the hardware and software of the PSDs, as well as its integration with the in-house experimental control software. Then practical examples of neutron scattering experiments for each of the upgraded facilities are presented.

The Frank Laboratory of Neutron Physics of the Joint Institute for Nuclear Research is one of the leading centers of neutron research in Russia. Within the works on the modernization of detector systems, researchers of the laboratory have designed and fabricated linear and area gas-filled position-sensitive detectors of thermal neutrons and the area monitor detector with a low attenuation of the incoming beam. These devices and their main characteristics have been described.

A one-dimensional position-sensitive detector of thermal neutrons has been developed to equip high-efficiency neutron spectrometers at the ИБР-2 research reactor. The detector is based on a multiwire proportional chamber filled with a mixture of 3He + CF4 and has an active area of 200 × 80 mm and a spatial resolution of 2 mm. The detector has been used to good effect in the REFLEX and HRFD spectrometers of the ИБР-2 reactor, as well as in the diffraction facility of the ИВВ-2M research reactor (Zarechnyi, Russia).

For high rate thermal neutron (and e.g. also synchrotron radiation) detection a PCI data acquisition (DAQ) board for readout of two-dimensional position-sensitive multi-wire proportional chamber (MWPC) detectors with delay line position encoding was developed, and a first series of boards was produced and tested. The MWPC board comprises a deadtime-less 8-channel multihit TDC chip of the F1 type with ∼120 ps LSB, a 40 MHz flash ADC, a FPGA, a FIFO, a 0.9 GFLOP DSP chip TMS320C6711 and a 256 MB histogram memory. For position encoding a position-independent start and four position-dependent stop signals are recorded from the MWPC anode and from either end of X and Y delay lines connected to the MWPC cathodes, respectively. Time-of-flight (TOF) can be measured with reference to a pulsed beam or chopper signal either with ⩾25 ns bin size for TOF ranges of up to ∼420 ms or alternatively with ∼120 ps LSB for ranges ⩽16 ms . The pulse height of the MWPC anode signal is digitized in the flash ADC for neutron-gamma and background discrimination. Hardware event filtering in the FPGA allows event rates up to 1 Mevents/s by disentangling of two events occurring within the delay line time length of e.g. 250 ns . Whilst list mode data are recorded with full rate and full resolution on the host PC disk, 1D–3D histograms can be accumulated online in the on-board HM for a fraction of the data and with reduced resolution.

For very high rate and resolution time-resolved experiments at next generation pulsed spallation neutron sources like ESS large-area hybrid low-pressure micro-strip gas chamber detectors are being developed. Due to theirthin composite converter foil and exponential gas multiplication commencing at the converter surfaces the detectors are free of parallax, and according to detailed modeling the very high transverse and longitudinal localization accuracies in the conversion and gas multiplication processes allow position and time resolutions of ∼100 μm and < 10 ns FWHM for thermal neutrons, respectively, the latter limited by the transit time through the converter. In the European R&D project TECHNI for this detector an advanced delay line readout technology with multi-event readout was developed as an economical solution for the majority of applications, which, however, limits the position resolution and rate capability to

The software package for the YuMO spectrometer has been updated. The MS DOS programs used before the updating are compared to the similar new programs operating in the OS-9 environment. The merits and demerits of each program are discussed. The main features of the new software are described, and the results of the long-term operation of the new software package are analyzed. It is shown that upgrading the software has improved spectrometer control.

The present paper is devoted to the development of methods and software to solve the deconvolution problem in neutron scattering data analysis. The problem itself is improperly posed, and Tikhonov's regularization method is chosen as a basis of the approach. The use of improved regularized solutions increases the effectiveness and accuracy of the calculating algorithm.

This work presents an improvement in the resulting scattering spectra quality due to the use of spectrometer resolution during both wavelet filtering and traditional smoothing the small-angle neutron scattering (SANS) data. This result leads to a better fitting of the form-factor curve at the next step of data analysis. In addition, the wavelet analysis permits one to extract and analyze a background (noisy) component and what is more to carry out instrumental hardware corrections.

Suffering presently from relatively low source strengths compared to synchrotron radiation investigations, neutron scattering methods will greatly benefit from the increase of instantaneous flux attained at the next generation of pulsed spallation neutron sources. In particular at ESS, the strongest projected source, the counting rate load on the detectors will rise by factors of up to 50–150 in comparison with present generic instruments. For these sources the detector requirements overlap partly with those for modern synchrotron radiation detectors as far as counting rate capability and two‐dimensional position resolution are concerned. In this paper, examples of the current and forthcoming detector development, comprising e.g. novel solutions for low‐pressure micro‐strip gas chamber detectors, for silicon micro‐strip detectors and for the related front‐end ASICs and data acquisition (DAQ) systems, are summarized, which will be of interest for detection of synchrotron radiation as well.

The presented work is aimed at the development of tools for data access, visualization, and manipulation of time-of-flight neutron spectrum data acquired from different spectrometers on the IBR-2 fast-pulsed reactor of the Frank Laboratory of Neutron Physics, JINR. Special tools, based on the PV-WAVE software package, for importing neutron data from IBR-2, exporting them in some common format, and data manipulations of such data have been developed by the author. Information about PV-WAVE-based tools for FLNP users is available on the Web.

We have examined numerically the transverse stability of solitons for the Kadomtsev-Petviashvili equation. The transverse stability region has been found in these computer experiments. Our results are consistent with those obtained from the Lyapunov functional method.