Design of an energetic particle radiation diagnostic spectroscopy system based on national core chips and Qt on Linux in EAST

Energetic particle radiation diagnoses mainly detect the particles(such as neutrons,gamma rays,hard X-rays,and escaping electrons)that are radiated in the discharge process of the experimental advanced superconducting tokamak device to characterize the operating state of the plasma in real time.The upgrading of these diagnoses requires new instruments based on national(here,“national”means developed and produced by a Chinese company)core chips and open-source software with advanced digitization,a high sampling rate,and a high time resolution.The new spectroscopy system designed in this study adopts the national field-programmable gate array(FPGA)and an analog-to-digital converter as the core chip,and it is developed using Qt on Linux.The communication between the FPGA and embedded controller occurs via a high-speed peripheral component interconnect eXtension for instrument express protocol with a direct memory access mode.On this basis,the time resolution of the system is improved from 2 to 1 ms,the maximum channel address is increased to 4096,and the sampling rate is increased from 10 to 80 Msps.Calibration experiments of the spectroscopy system with 152Eu and 137Cs sources demonstrate that the best energy resolution is 0.27%and the measurement error is less than±0.5 keV.

Induction of adaptive response in utero by ionizing radiation:A radiation quality dependent phenomenon

Investigation on possible induction of adaptive response(AR)by high-liner energy transfer(LET)particle radiation for protection against low-LET photon radiation-induced detrimental effects has not yet been performed in utero.This study verified if an AR could be induced by high-LET particle radiation from accelerated heavy ions against low-LET X-ray radiation-induced detrimental effects on fetal mice.Total body irradiation of pregnant C57BL/6J mice were performed by delivering a priming dose ranging from 10 mGy to 320 mGy of particle radiation on gestation day 11 followed one day later by a challenge dose at 3500 mGy from X-ray radiation.The monoenergetic beams of carbon,silicon and iron with the LET values of about 15,55,and 200 KeV/μm,respectively,were examined.Significant suppression by the priming radiation of the detrimental effects(fetal death,malformation,or low body weight)was used as the endpoints for judgment of a successful AR induction on gestation day 18.Existence of AR was not observed.On the other hand,the priming dose of high-LET particle radiation,in some cases,even increased the detrimental effects induced by the challenge dose from low-LET X-ray radiation.Although existence of AR induced by high-LET radiation in cultured mammalian cells in vitro and in certain tissues of laboratory mice in vivo was demonstrated,the present study did not suggest that low dose of high-LET particle radiation could induce an AR in fetal mice in utero under the setup of our experimental system.

Influence of syngas components and ash particles on the radiative heat transfer in a radiant syngas cooler

Radiant syngas cooler(RSC)is widely used as a waste heat recovery equipment in industrial gasification.In this work,an RSC with radiation screens is established and the impact of gaseous radiative property models,gas components,and ash particles on heat transfer is investigated by the numerical simulation method.Considering the syngas components and the pressure environment of the RSC,a modified weighted-sum-of-gray-gases model was developed.The modified model shows high accuracy in validation.In computational fluid dynamics simulation,the calculated steam production is only 0.63%in error with the industrial data.Compared with Smith's model,the temperature decay along the axial direction calculated by the modified model is faster.Syngas components are of great significance to heat recovery capacity,especially when the absorbing gas fraction is less than 10%.After considering the influence of particles,the outlet temperature and the proportion of radiative heat transfer are less affected,but the difference in steam output reaches 2.7 t·h^(-1).The particle deposition on the wall greatly reduces the heat recovery performance of an RSC.

Insights into metals in individual fine particles from municipal solid waste using synchrotron radiation-based micro-analytical techniques

Excessive inter-contamination with heavy metals hampers the application of biological treatment products derived from mixed or mechanically-sorted municipal solid waste（MSW）. In this study, we investigated fine particles of 〈 2 mm, which are small fractions in MSW but constitute a significant component of the total heavy metal content, using bulk detection techniques. A total of 17 individual fine particles were evaluated using synchrotron radiation-based micro-X-ray fluorescence and micro-X-ray diffraction. We also discussed the association, speciation and source apportionment of heavy metals. Metals were found to exist in a diffuse distribution with heterogeneous intensities and intense hot-spots of 〈 10 μm within the fine particles. Zn–Cu, Pb–Fe and Fe–Mn–Cr had significant correlations in terms of spatial distribution. The overlapped enrichment, spatial association, and the mineral phases of metals revealed the potential sources of fine particles from size-reduced waste fractions（such as scraps of organic wastes or ceramics） or from the importation of other particles. The diverse sources of heavy metal pollutants within the fine particles suggested that separate collection and treatment of the biodegradable waste fraction（such as food waste） is a preferable means of facilitating the beneficial utilization of the stabilized products.

An Annular Gap Acceleration Model for γ-ray Emission of Pulsars

If the binding energy of the pulsar＇s surface is not so high （the case of a neutron star）, both negative and positive charges will flow out freely from the surface of the star. An annular free flow model for 7-ray emission of pulsars is suggested. It is emphasized that： （1） Two kinds of acceleration regions （annular and core） need to be taken into account. The annular acceleration region is defined by the magnetic field lines that cross the null charge surface within the light cylinder. （2） If the potential drop in the annular region of a pulsar is high enough （normally the case for young pulsars）, charges in both the annular and the core regions could be accelerated and produce primary gamma-rays. Secondary pairs are generated in both regions and stream outwards to power the broadband radiations. （3） The potential drop grows more rapidly in the annular region than in the core region. The annular acceleration process is a key process for producing the observed wide emission beams. （4） The advantages of both the polar cap and outer gap models are retained in this model. The geometric properties of the 7-ray emission from the annular flow are analogous to that pre-sented in a previous work by Qiao et al., which match the observations well. （5） Since charges with different signs leave the pulsar through the annular and the core regions respectively, the current closure problem can be partially solved.