Time Projection Chamber (TPC) is the main tracker of the Multi-Purpose Detector (MPD) at the Joint Institute for Nuclear Research for the NICA collider (Nuclotron-based Ion Collider fAcility). The ...TPC Front-End Electronics (FEE) will operate with event rate up to 7 kHz. The electronics is based on the novel ASIC SAMPA, FPGAs and high-speed serial links. Each of 24 readout chambers will be served by 62 Front-End Cards (FEC) and one Readout and Control Unit (RCU). The whole system will contain 1488 FECs and 24 RCUs. The total number of registration channels is 95232. The article presents the current status of the FEE development and results of the FEC testing.
The relationship between
sp
2
/
sp
3
hybridizations ratio of atomic bonds in diamond-like carbon (DLC) and its electrical resistivity for coatings with a thickness in the range 22–70 nm prepared by ...vacuum arc deposition on silicon substrate of the SHB-8 brand has been established. It is established, that an increase in the coating thickness from 22 to 70 nm is accompanied by a decrease in the specific transverse electrical resistance of samples from 17 to 2 GΩ m. This effect is explained by an increase in the proportion of carbon atoms with
sp
2
hybridization of electronic orbitals from 86 to 91%, which leads to the appearance of an additional number of π-bonds. A mathematical model describing the spatial distribution of current when measuring the transverse
I–V
characteristic, has been developed. The results obtained will be useful in creating resistive layers on the electrodes of gas-discharge detectors of charged particle to limit the amount of c-urrent in the event of rare spark discharges inside them caused by the registration of random highly ionizing pa-rticles.
The data acquisition system (DAQ) was designed for data taking from the TPC/MPD detector. The detector contains 95232 registration channels, includes 1488 Front-End Cards (FEC) and other modules ...grouped into 24 DAQ subsystems. Each FEC has an individual full-duplex few-gigabit communication channel with Readout and Control Unit (RCU). The RCU manages each FEC within the group, collects the data and then transmits them via a high-speed optical channel. Optical lines from each group of four RCUs are connected to the Local Data Concentrator (LDC) computer via a Data Concentrator Unit (DCU) module installed. Each of the six DCUs controls four RCUs, receives data from them and stores them into the LDC computer memory via the PCIe interface. The DAQ system is operating with a raw TPC event of the size up to 37 MB containing information up to 2000 tracks at the central collision and the event trigger rate of up to 7 kHz in zero suppression mode. The article presents the overall structure of the system and the realized functionality of its main components. Section 1 describes the arrangement of DAQ subsystems and modules inside MPD. Section 2 gives the function, structure and connections of DAQ subsystems. Section 3 describes in detail one of the 24 DAQ subsystems. Section 4 presents the scheme of the local storage of TPC data and communication with MPD DAQ. In Section 5, the system throughput is estimated. Section 6 summarizes the main performance indicators and key technologies used in the construction of the system.
Abstract
A prototype of the WEM (Well Electron Multiplier) detector with an active area of 10 × 10 mm
2
and a resistive DLC anode was tested in terms of robustness to electrical discharges induced by ...highly ionizing particles (
241
Am alpha source). The perforated structure of the WEM detector was produced from a 500 μm thick FR4 with drilled holes of 200 μm in diameter and 500 μm in pitch. The resistive anode was made of 100 nm thick DLC layer with 30 MOhm/square sheet resistance deposited on the anode grid electrode. The anode grid electrode is used to distribute voltage to the resistive layer and provide fast charge evacuation. The detector was operated in Ar:CO
2
(90:10) gas mixture at gas gain of 3,500. The alpha source was placed in the drift gap. The WEM detector with intrinsic capacitance of 34 pF did not show visible damage and changes in performance after 1 million accumulated discharges. To simulate a large area detector, we added a capacitance up to 1 nF in parallel with the test device. The results of the experiments with an additional capacitance revealed that a small WEM prototype can't be directly scaled to the dimensions more than 60 × 60 mm
2
without losing the robustness to discharges. We assume that the observed damage could be caused by the design features of the prototype. The grid anode electrode with a thickness of 35 μm results in a gap between the perforated FR4 board and the resistive anode board. Simulations of the electric field distribution with Comsol Multiphysics software revealed a significant electric field strength in this gap. This could lead to electric discharge path bypassing the protective resistive DLC layer. A possible solution to this problem could be additional insulation of the anode grid electrode with a coverlay similar to that used in bulk MicroMegas production.
Results of an electrical field simulation for various configurations of new 2D position-sensitive detectors based on the gas-filled multiwire electron multiplier (MWEM) are presented. In contrast to ...the multiwire proportional chambers (MWPCs), an avalanche multiplication of the primary charge in the MWEM occurs in between wires
1
, and high loading capability and counting rates with submillimeter spatial resolution can be achieved in this case.
The article is aimed at describing the development status, measuring results and design changes of the TPC front-end electronics. The TPC is placed in the middle of Multi-Purpose Detector (MPD) and ...provides tracing and identifying of charged particles in the pseudorapidity range |η|<1.2. The readout system is one of the most complex parts of the TPC. The electronics of each readout chamber is an independent system. The whole system contains 95232 channels, 1488 64-channel—front-end cards (FEC), 24 readout control units (RCU). The front-end electronics (FEE) is based on ASICs, FPGAs and high-speed serial links. The concept of the TPC front-end electronics has been motivated from one side—by the requirements concerning the NICA accelerator complex which will operate at the luminosity up to 1027 cm−2 s−1 for Au79+ ions over the energy range of 4< SNN<11 GeV with the trigger rate up to 7 kHz and from the other side—by the requirements of the 4-π geometry to minimize the substance on the end-caps of the TPC.
Straw tubes with resistive cathode and cathode readout were successfully manufactured and tested. The straw tubes were manufactured by ultrasonic welding technique. The resistive cathode electrode ...was made of diamond like carbon (DLC). The possibility of cathode signal readout from external strip electrodes was successfully demonstrated. The event coordinate along the straw can be accurately determined by applying center of gravity method to the individual strip signals.
The aim of this work is to determine the effect of the elements, which do not participate in heat transfer, on the mass of the regenerator of a gas turbine plant X, as well as to define the ...re-strictions that are imposed on the regenerator design based on the conditions of manufacturabil-ity, placement at the facility and transportability. This goal is achieved using an algorithm for finding rational geometric parameters of the heat exchange matrix with minimization of the re-generator mass by Newton's method. It has been determined that the mass of the heat exchange matrix can be 0.48–0.58 of the mass of the regenerator. This makes it necessary, even at the initial design stages, to take into account the effect of the above factors on the mass of the re-generator and the choice of the rational geometrical parameters. A significant result of the stud-ies performed is determination of the effect of dimensional restrictions and requirements for the shape of the regenerator to be increased in its mass. The values of the geometrical parameters of the heat exchange matrix were obtained, at which the mass of the regenerator takes on a mini-mum value. The significance of the work is that the obtained relationships between the mass of the regenerator and its geometry makes it possible to reduce the metal consumption of the regen-erator and the gas turbine plant, which allows designing the heat exchangers for power plants
MPD TPC Status Averyanov, A.; Balashov, I.; Bazhazhin, A. ...
Physics of atomic nuclei,
10/2023, Letnik:
86, Številka:
5
Journal Article
Recenzirano
In the framework of the JINR scientific program on study of hot and dense baryonic matter a new accelerator complex Ion Collider fAcility (NICA) based on the Nuclotron-M is under realization. It will ...operate at a luminosity up to
cm
s
for ions up to Au79+. Two interaction points are foreseen at NICA for two detectors which will operate simultaneously. One of these detectors, the Multi-Purpose Detector (MPD), is optimized for investigations of heavy-ion collisions. The Time-Projection Chamber (TPC) is a well-known detector for 3-dimensional tracking and particle identification for high multiplicity events. The conceptual layout of MPD, TPC design and its parameters, the current status of the readout based on multiwire proportional chamber (MWPC) and readout electronics based on SAMPA chip as well as the status of TPC subsystems are presented.
Microscope investigations of new-type thin-wall tubes (straws) produced for NA62 drift chambers revealed that they are semitransparent and allow anode wires to be observed under illumination by ...visible light. In this work it is shown that positions of wires in straws and thus the anode spacing in the drift chambers can be directly determined with a high accuracy (~5–10µm) using a microscope mounted on a high-precision optical bench. These data are important for decreasing errors during reconstruction of charged particle track coordinates in the drift chambers. The proposed technique is much simpler than the X-ray or radioactive source methods.
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