V. S. Petrov

Spectrometer with a vertex detector for experiments at the IHEP accelerator

The stages of development and the current status of the versatile “Spectrometer with a Vertex Detector” setup designed for physics experiments at the U-70 accelerator of the Institute for High Energy Physics (Protvino) is described. The main detectors of the setup are the vertex detector based on silicon microstrip detectors, the wide-aperture magnetic spectrometer based on multiwire proportional chambers, and the lead-glass hodoscope γ detector. In the setup, there is a fast two-level trigger system for selecting required particle interactions. The key characteristics of the setup systems are presented, and the physical results obtained on it are briefly listed.

Measurement of the production cross section for charmed baryons in proton–nucleus interactions at 70 GeV

The results of an analysis of data from the SERP-Е-184 experiment devoted to studying mechanisms of the production of charmed particles in proton–nucleus interactions at 70 GeV and their decays are presented. The data in question were obtained upon irradiating the SVD-2 active target consisting of carbon, silicon, and lead plates with a beam of 70-GeV protons. A detailed simulation on the basis of the FRITIOF7.02 and GEANT3.21 code packages made it possible to optimize event-selection criteria and to calculate the detection efficiency for Λc+ baryons. After selecting a signal from the threebody decay of a Λc+ baryon, the inclusive cross section for its production at near-threshold energies, its lifetime, and the parameter of the A dependence of the cross section were found. The Λc+ -baryon yields are tabulated along with data from other experiments and theoretical predictions.

Tokamak DEMO-FNS: Concept of magnet system and vacuum chamber

The level of knowledge accumulated to date in the physics and technologies of controlled thermonuclear fusion (CTF) makes it possible to begin designing fusion—fission hybrid systems that would involve a fusion neutron source (FNS) and which would admit employment for the production of fissile materials and for the transmutation of spent nuclear fuel. Modern Russian strategies for CTF development plan the construction to 2023 of tokamak-based demonstration hybrid FNS for implementing steady-state plasma burning, testing hybrid blankets, and evolving nuclear technologies. Work on designing the DEMO-FNS facility is still in its infancy. The Efremov Institute began designing its magnet system and vacuum chamber, while the Kurchatov Institute developed plasma-physics design aspects and determined basic parameters of the facility. The major radius of the plasma in the DEMO-FNS facility is R = 2.75 m, while its minor radius is a = 1 m; the plasma elongation is k95 = 2. The fusion power is PFUS = 40 MW. The toroidal magnetic field on the plasma-filament axis is Bt0 = 5 T. The plasma current is Ip = 5 MA. The application of superconductors in the magnet system permits drastically reducing the power consumed by its magnets but requires arranging a thick radiation shield between the plasma and magnet system. The central solenoid, toroidal-field coils, and poloidal-field coils are manufactured from, respectively, Nb3Sn, NbTi and Nb3Sn, and NbTi. The vacuum chamber is a double-wall vessel. The space between the walls manufactured from 316L austenitic steel is filled with an iron—water radiation shield (70% of stainless steel and 30% of water).

A multicomputer data acquisition complex based on MISS and SUMMA electronics for the Hyperon-M experiment

A structure of the multicomputer data acquisition complex for the Hyperon-M experiment at the U-70 accelerator (Protvino, Russia) is described. This complex has been designed to collect and merge data from several particle detectors, the electronic systems of which are made either to the MISS or SUMMA standard. The MISS system is autonomously operated under control of a special ЛЭ-74 controller that collects information in its internal buffer storage during a beam spill. The data acquired are combined with the information from the SUMMA electronics and are copied to an external storage device (a hard disk of a computer) in intervals between spills. On the contrary, software control is needed for the SUMMA electronics to read data on each event. Software-and hardware-based methods are used to provide joint operation of the electronic systems made to diverse standards and guarantee that the streams of incoming data are correctly merged. The problems of net interactions between different parts of the multicomputer system and monitoring of this system are analyzed.

A vertex microstrip detector of the SVD setup for experiments on the IHEP accelerator

A precision vertex microstrip detector has been developed for the spectrometer with a vertex detector (SVD) setup on which the properties of hadrons and short-lived unstable particles are investigated on the accelerator of the Institute for High Energy Physics. The structure and the design of the main detector components—microstrip sensors and an active target—are presented, as well as techniques for manufacturing them. The readout electronics, the data acquisition system, and its software are also described. The accuracy in determining the vertex position is 70–250 µm along the beam axis and 8–15 µm in a transverse direction at a throughput of 500–1000 events/s.

A data acquisition system of the “Hyperon-M” experiment on basis of the MISS electronics and controller with internal hardware buffering

The structure of the fast data acquisition system collecting data from multichannel particle detectors for experiments on an accelerator, which is based on MISS electronics, is described. A special feature of the architecture used is the ЛЭ-74 specialized controller that independently reads data from the detectors into the internal memory buffer on a real-time scale in the course of the beam spilling into the target. The stored information is rewritten from the internal buffer on the hard disk of the computer. The data are further transmitted via the local network in intervals between spills. This scheme allows one to avoid accessing slow peripherals in the course of the beam spill and, thus, to attain a speed that is only limited by the response speed of the used circuitry components. In tests conducted as part of the Hyperon-M experiment on the U-70 accelerator, an experimental data collection speed of up to 9 Mbyte/s was attained, which is comparable with the data transmission speed in existing local communication networks.

A light-emitting diode monitoring system of the PHOS photon spectrometer in the ALICE experiment on the large hadron collider

A light-emitting diode (LED) monitoring system of the PHOS photon spectrometer in the ALICE experiment on the CERN large hadron collider is described. The spectrometer includes three modules in the form of 64 × 56 matrices consisting of plumbum tungstate (PWO) crystals. As test light signal sources, Kingbright L934SCC superbright green light-emitting diodes with an individual instrumental regulation of light flash intensities in each channel of the spectrometer are used. The system ensures adjustment and monitoring of the electronics at the stage of preparing for the physical trigger of the PHOS modules and is intended to perform special test measurements with the spectrometer without using high-energy particles. In addition, in the course of the experiment, it allows one to promptly monitor each channel of the spectrometer and keep track of temperature variations of the light yield of the PWO crystals. In this case, the long-term relative channel monitoring stability is ensured at a 1.2 × 10−3 level.

Scaling Modules for the IHEP Experimental Setups

Multichannel scaling modules, which have a high response speed and meet the specific requirements of experiments conducted with the IHEP physical setups, are described. The scaling modules are made to SUMMA, MISS, and Euromechanics standards and use high-speed microcircuits of the 1500 family and programmable logic integrated circuits from Altera.