Research on dose correction method of vehicle-borne environmental radiation measurement equipment

Abstract This study establishes a near-ground reference radiation field based on typical radionuclides of the Fukushima accident in response to the need for vehicle-borne environmental radiation measurement equipment that can accurately evaluate the environmental dose of nuclear accidents. The Monte Carlo code FLUKA is used to study the environmental dose of such equipment in the early and mid-late reference radiation fields of nuclear accidents. Results of the air dose rate at 1 m above the ground were corrected to eliminate data difference between diverse measurement platforms. Simulation results show that t he dose correction factor (CF) fluctuates at approximately 0.8813 in the early reference radiation field and at approximately 0.6711 in the mid-late reference radiation field. This deviation of the dose CF in the early and mid-late reference radiation fields is within 2% and is not affected by the change in detector position. This research can be applied to obtain more accurate measurement of an ambient dose in the near-ground radiation field and support the vehicle-borne environmental radiation measurement technology.

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Microdosimetry of Environmental Radiation Fields

Fundamentals for the Assessment of Risks from Environmental Radiation ◽

10.1007/978-94-011-4585-5_65 ◽

1999 ◽

pp. 497-502

Author(s):

F. Spurny ◽

J.-F. Bottollier-Depois

Keyword(s):

Environmental Radiation ◽

Radiation Fields

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Radiative cooling rates, ion fractions, molecule abundances, and line emissivities including self-shielding and both local and metagalactic radiation fields

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2172 ◽

2020 ◽

Vol 497 (4) ◽

pp. 4857-4883 ◽

Cited By ~ 2

Author(s):

Sylvia Ploeckinger ◽

Joop Schaye

Keyword(s):

Cosmic Rays ◽

Radiation Field ◽

Spectral Synthesis ◽

Cosmic Ray ◽

Cooling Rates ◽

Radiation Fields ◽

Hydrodynamical Simulations ◽

Lower Temperature ◽

X Ray Background ◽

Ionization Balance

ABSTRACT We use the spectral synthesis code cloudy to tabulate the properties of gas for an extensive range in redshift (z = 0–9), temperature (log T[K] = 1–9.5), metallicity (log Z/Z⊙ = −4 – +0.5, Z = 0), and density ($\log n_{\mathrm{H}}[\, \mathrm{cm}^{-3}] = -8$ − +6). This therefore includes gas with properties characteristic of the interstellar, circumgalactic, and intergalactic media. The gas is exposed to a redshift-dependent UV/X-ray background, while for the self-shielded lower-temperature gas (i.e. ISM gas), an interstellar radiation field and cosmic rays are added. The radiation field is attenuated by a density- and temperature-dependent column of gas and dust. Motivated by the observed star formation law, this gas column density also determines the intensity of the interstellar radiation field and the cosmic ray density. The ionization balance, molecule fractions, cooling rates, line emissivities, and equilibrium temperatures are calculated self-consistently. We include dust, cosmic rays, and the interstellar radiation field step-by-step to study their relative impact. These publicly available tables are ideal for hydrodynamical simulations. They can be used stand alone or coupled to a non-equilibrium network for a subset of elements. The release includes a C routine to read in and interpolate the tables, as well as an easy-to-use python graphical user interface to explore the tables.

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Modeling Compact Intracloud Discharge (CID) as a Streamer Burst

Atmosphere ◽

10.3390/atmos11050549 ◽

2020 ◽

Vol 11 (5) ◽

pp. 549

Author(s):

Vernon Cooray ◽

Gerald Cooray ◽

Marcos Rubinstein ◽

Farhad Rachidi

Keyword(s):

Electric Field ◽

Electrical Activity ◽

Radiation Field ◽

Time Derivative ◽

Vertical Direction ◽

Maximum Growth ◽

Nanosecond Duration ◽

Peak Current ◽

Radiation Fields ◽

Large Current

Narrow Bipolar Pulses are generated by bursts of electrical activity in the cloud and these are referred to as Compact Intracloud Discharges (CID) or Narrow Bipolar Events in the current literature. These discharges usually occur in isolation without much electrical activity before or after the event, but sometimes they are observed to initiate lightning flashes. In this paper, we have studied the features of CIDs assuming that they consist of streamer bursts without any conducting channels. A typical CID may contain about 109 streamer heads during the time of its maximum growth. A CID consists of a current front of several nanosecond duration that travels forward with the speed of the streamers. The amplitude of this current front increases initially during the streamer growth and decays subsequently as the streamer burst continues to propagate. Depending on the conductivity of the streamer channels, there could be a low-level current flow behind this current front which transports negative charge towards the streamer origin. The features of the current associated with the CID are very different from those of the radiation field that it generates. The duration of the radiation field of a CID is about 10–20 μs, whereas the duration of the propagating current pulse associated with the CID is no more than a few nanoseconds in duration. The peak current of a CID is the result of a multitude of small currents associated with a large number of streamers and, if all the forward moving streamer heads are located on a single horizontal plane, the cumulative current that radiates at its peak value could be about 108 A. On the other hand, the current associated with an individual streamer is no more than a few hundreds of mA. However, if the location of the forward moving streamer heads are spread in a vertical direction, the peak current can be reduced considerably. Moreover, this large current is spread over an area of several tens to several hundreds of square meters. The study shows that the streamer model of the CID could explain the fine structure of the radiation fields present both in the electric field and electric field time derivative.

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Accretion-Disk Corona Advected by External Radiation Drag

Symposium - International Astronomical Union ◽

10.1017/s0074180900115785 ◽

1998 ◽

Vol 188 ◽

pp. 413-414

Author(s):

Y. Watanabe ◽

J. Fukue

Keyword(s):

Angular Momentum ◽

Radiation Field ◽

Accretion Disk ◽

Accretion Disks ◽

External Radiation ◽

Radiation Fields ◽

Almost All ◽

Strong Radiation ◽

Radiative Interaction ◽

Standard Disk

Accretion-disk corona (ADC) is required from observational as well as theoretical reasons. In almost all of traditional studies, however, a stationary corona has been assumed; i.e., the corona gas corotates with the underlying (Keplerian) accretion disk, and the radial motion is ignored. Recently, in the theory of accretion disks a radiative interaction between the gas and the external radiation field has attracted the attention of researchers. In particular the radiation drag between the gas and the external radiation field becomes important from the viewpoint of the angular-momentum removal. We thus examine the effect of radiation drag on the accretion-disk corona above/below the accretion disk (Watanabe, Fukue 1996a, b). We suppose that an accretion disk can be described by the standard disk, and that radiation fields are produced by the central luminous source and the accretion disk, itself. In general an accretion-disk corona under the influence of strong radiation fields dynamically infalls (advected) toward the center.

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Exact solutions of the field equations: twist-free pure radiation fields

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1962.0224 ◽

1962 ◽

Vol 270 (1342) ◽

pp. 328-334 ◽

Cited By ~ 30

Keyword(s):

General Relativity ◽

Exact Solutions ◽

Radiation Field ◽

Relativity Theory ◽

Vacuum Field ◽

Field Equations ◽

General Relativity Theory ◽

Pure Radiation ◽

Radiation Fields ◽

Null Congruence

This note is intended to give a rough survey of the results obtained in the study of twist-free pure radiation fields in general relativity theory. Here we are using the following Definition. A space-time ( V 4 of signature +2) is called a pure radiation field if it contains a distortion-free geodetic null congruence (a so-called ray congruence ), and if it satisfies certain field equations which we will specify below (e.g. Einstein’s vacuum-field equations). A (null) congruence is called twist-free if it is hypersurface-orthogonal (or ‘normal’). The results listed below were obtained by introducing special (‘canonical’) co-ordinates adapted to the ray congruence. Detailed proofs were given by Robinson & Trautman (1962) and by Jordan, Kundt & Ehlers (1961) (see also Kundt 1961). For the sake of completeness we include in our survey the subclass of expanding fields, and make use of some formulae first obtained by Robinson & Trautman.

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Remote and Feedback Control of the Flap Angle in a Wind Tunnel Test Model by Optical Measurement

Aerospace ◽

10.3390/aerospace7020011 ◽

2020 ◽

Vol 7 (2) ◽

pp. 11

Author(s):

Kazuhisa Chiba ◽

Tatsuro Komatsu ◽

Hiroyuki Kato ◽

Kazuyuki Nakakita

Keyword(s):

Feedback Control ◽

Wind Tunnel ◽

Optical Measurement ◽

Wind Tunnel Test ◽

Measurement Technology ◽

Test Model ◽

Measurement Equipment ◽

Feedback Control System ◽

Aerodynamic Coefficients ◽

Japan Aerospace Exploration Agency

We have developed a remote and precise feedback control system using optical measurement technology to alter the angle of a flap, which is part of a wind tunnel test model, automatically and to earn the aerodynamic data efficiently. To rectify the wasteful circumstance that Japan Aerospace Exploration Agency (JAXA)’s low-turbulence wind tunnel stops ventilation every time to switch model configurations, we repaired hardware for remote operation and generated software for feedback control. As a result, we have accomplished a system that dramatically advances the efficiency of wind tunnel tests. Moreover, the system was able to consider the deformation of the model through optical measurement; the system controlled flap angles with errors less than the minimum resolution of optical measurement equipment. Consequently, we successfully grasped the nonlinearity of three aerodynamic coefficients C L , C D , and C M p that was impossible so far.

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9.17. Accretion disk winds driven by the disk radiation field under radiation drag

Symposium - International Astronomical Union ◽

10.1017/s0074180900085442 ◽

1998 ◽

Vol 184 ◽

pp. 415-416

Author(s):

Y. Tajima ◽

J. Fukue

Keyword(s):

Radiation Field ◽

Accretion Disk ◽

Ionized Gas ◽

Radiation Fields ◽

Intense Radiation

The radiative winds from a geometrically thin accretion disk are studied. The effect of radiation drag which causes in the intense radiation fields around the accretion disk is examined recently. Then, we numerically consider the radiatively-accelerated accretion-disk winds which consist of ionized gas particles, taking into account radiation drag of the order ofv/c.

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Relationship between pneumonitis induced by immune checkpoint inhibitors and the underlying parenchymal status: a retrospective study

ERJ Open Research ◽

10.1183/23120541.00165-2019 ◽

2020 ◽

Vol 6 (1) ◽

pp. 00165-2019 ◽

Cited By ~ 1

Author(s):

Chiara Pozzessere ◽

Hasna Bouchaab ◽

Raphael Jumeau ◽

Igor Letovanec ◽

Cécile Daccord ◽

...

Keyword(s):

Radiation Field ◽

Immune Checkpoint ◽

Immune Checkpoint Inhibitors ◽

Checkpoint Inhibitors ◽

Primary Tumour ◽

Treatment Interruption ◽

Immunosuppressive Drug ◽

Lung Tumour ◽

Radiation Fields ◽

Tumour Metastasis

In patients with primary or secondary lung tumour treated with immune checkpoint inhibitors, immune-related pneumonitis is a rare adverse event but may evolve to respiratory failure. Prompt management is required and usually consists of treatment interruption and immunosuppressive drug administration. The aim of this study was to evaluate relationships between immune-related pneumonitis and pre-existing parenchymal status, especially tumour location and history of chest radiotherapy.Computed tomography (CT) scans of patients with immune-related pneumonitis were retrospectively reviewed. Pattern, distribution and extent of pneumonitis were assessed in six lung regions. In patients who received radiotherapy, the extent of pneumonitis was evaluated according to the radiation field.Among 253 patients treated with immunotherapy, 15 cases of immune-related pneumonitis were identified. 10 had previous or concomitant chest radiotherapy in addition to immunotherapy. At CT scan, 29 (33%) out of 88 regions encompassed the primary tumour (n=4), a lung metastasis (n=4) and/or radiation fields (n=21). A significantly higher prevalence of parenchymal involvement by immune-related pneumonitis occurred within areas of primary or metastatic malignancy and/or radiation field (97%) as compared to other areas (3%, p=0.009). Lung regions affected by the primary tumour, metastasis or radiotherapy had a higher probability of immune-related pneumonitis than others (OR 10.8, p=0.024). An organising pneumonia (OP) pattern was more frequent after radiotherapy (70% versus 0%, p=0.024), whereas nonspecific interstitial pneumonia features were more commonly seen in radiotherapy-naive patients (100% versus 10%, p=0.002).In patients with primary or secondary lung tumour treated with immune checkpoint inhibitors, immune-related pneumonitis is preferentially located within lung areas involved by tumour and/or radiation fields.

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Studies of radiation fields of LCLS-II super conducting radio frequency cavities

International Journal of Modern Physics Conference Series ◽

10.1142/s201019451660209x ◽

2016 ◽

Vol 44 ◽

pp. 1660209 ◽

Cited By ~ 2

Author(s):

M. Santana Leitner ◽

L. Ge ◽

Z. Li ◽

C. Xu ◽

C. Adolphsen ◽

...

Keyword(s):

Radio Frequency ◽

Dark Current ◽

3D Model ◽

Monte Carlo Code ◽

Coherent Light ◽

X Ray ◽

Radiation Fields ◽

Custom Made ◽

Linac Coherent Light Source ◽

Super Conducting

The Linac Coherent Light Source II (LCLS-II) will be a hard X-ray Free Electron Laser whose linac can deliver a 1.2 MW CW electron beam with bunch rates up to 1 MHz. To efficiently generate such a high power beam, Super-Conducting Radio-Frequency (SCRF) cavities will be installed in the upstream portion of the existing 3 km Linac at the SLAC National Accelerator Laboratory. The 9-cell niobium cavities will be cooled at 2K inside 35 cryomodules, each containing a string of eight of those cavities followed by a quadrupole. The strong electromagnetic fields in the SCRF cavities will extract electrons from the cavity walls that may be accelerated. Most such dark current will be deposited locally, although some electrons may reach several neighboring cryomodules, gaining substantial energy before they hit a collimator or other aperture. The power deposited by the field emitted electrons and the associated showers may pose radiation and machine protection issues at the cryomodules and also in other areas of the accelerator. Simulation of these effects is therefore crucial for the design of the machine. The in-house code Track3P was used to simulate field emitted electrons from the LCLS-II cavities, and a sophisticated 3D model of the cryomodules including all cavities was written to transport radiation with the Fluka Monte Carlo code, which was linked to Track3P through custom-made routines. This setup was used to compute power deposition in components, prompt and residual radiation fields, and radioisotope inventories.

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