10 CFR 20.1602 - Control of access to very high radiation areas.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Control of access to very high radiation areas. 20.1602 Section 20.1602 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Control of Exposure From External Sources in Restricted Areas § 20.1602 Control of access to very high radiation areas...

10 CFR 20.1602 - Control of access to very high radiation areas.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Control of access to very high radiation areas. 20.1602 Section 20.1602 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Control of Exposure From External Sources in Restricted Areas § 20.1602 Control of access to very high radiation areas...

10 CFR 20.1602 - Control of access to very high radiation areas.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Control of access to very high radiation areas. 20.1602 Section 20.1602 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Control of Exposure From External Sources in Restricted Areas § 20.1602 Control of access to very high radiation areas...

10 CFR 835.1201 - Sealed radioactive source control.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 4 2010-01-01 2010-01-01 false Sealed radioactive source control. 835.1201 Section 835.1201 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Sealed Radioactive Source Control § 835.1201 Sealed radioactive source control. Sealed radioactive sources shall be used, handled, and...

10 CFR 835.1201 - Sealed radioactive source control.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 4 2011-01-01 2011-01-01 false Sealed radioactive source control. 835.1201 Section 835.1201 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Sealed Radioactive Source Control § 835.1201 Sealed radioactive source control. Sealed radioactive sources shall be used, handled, and...

10 CFR 835.1201 - Sealed radioactive source control.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 4 2013-01-01 2013-01-01 false Sealed radioactive source control. 835.1201 Section 835.1201 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Sealed Radioactive Source Control § 835.1201 Sealed radioactive source control. Sealed radioactive sources shall be used, handled, and...

10 CFR 835.1201 - Sealed radioactive source control.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 4 2014-01-01 2014-01-01 false Sealed radioactive source control. 835.1201 Section 835.1201 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Sealed Radioactive Source Control § 835.1201 Sealed radioactive source control. Sealed radioactive sources shall be used, handled, and...

10 CFR 835.1201 - Sealed radioactive source control.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 4 2012-01-01 2012-01-01 false Sealed radioactive source control. 835.1201 Section 835.1201 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Sealed Radioactive Source Control § 835.1201 Sealed radioactive source control. Sealed radioactive sources shall be used, handled, and...

[Use of ionizing radiation sources in metallurgy: risk assessment].

PubMed

Giugni, U

2012-01-01

Use of ionizing radiation sources in the metallurgical industry: risk assessment. Radioactive sources and fixed or mobile X-ray equipment are used for both process and quality control. The use of ionizing radiation sources requires careful risk assessment. The text lists the characteristics of the sources and the legal requirements, and contains a description of the documentation required and the methods used for risk assessment. It describes how to estimate the doses to operators and the relevant classification criteria used for the purpose of radiation protection. Training programs must be organized in close collaboration between the radiation protection expert and the occupational physician.

10 CFR 835.502 - High and very high radiation areas.

Code of Federal Regulations, 2010 CFR

2010-01-01

... device that functions automatically to prevent use or operation of the radiation source or field while... gain unauthorized or inadvertent access to very high radiation areas. (d) No control(s) shall be...

10 CFR 835.502 - High and very high radiation areas.

Code of Federal Regulations, 2013 CFR

2013-01-01

... device that functions automatically to prevent use or operation of the radiation source or field while... gain unauthorized or inadvertent access to very high radiation areas. (d) No control(s) shall be...

10 CFR 835.502 - High and very high radiation areas.

Code of Federal Regulations, 2011 CFR

2011-01-01

... device that functions automatically to prevent use or operation of the radiation source or field while... gain unauthorized or inadvertent access to very high radiation areas. (d) No control(s) shall be...

10 CFR 835.502 - High and very high radiation areas.

Code of Federal Regulations, 2012 CFR

2012-01-01

... device that functions automatically to prevent use or operation of the radiation source or field while... gain unauthorized or inadvertent access to very high radiation areas. (d) No control(s) shall be...

10 CFR 835.502 - High and very high radiation areas.

Code of Federal Regulations, 2014 CFR

2014-01-01

... device that functions automatically to prevent use or operation of the radiation source or field while... gain unauthorized or inadvertent access to very high radiation areas. (d) No control(s) shall be...

Active noise control using noise source having adaptive resonant frequency tuning through stress variation

NASA Technical Reports Server (NTRS)

Pla, Frederic G. (Inventor); Renshaw, Anthony A. (Inventor); Rajiyah, Harindra (Inventor); Hedeen, Robert A. (Inventor)

1995-01-01

A noise source for an aircraft engine active noise cancellation system in which the resonant frequency of a noise radiating element is tuned to permit noise cancellation over a wide range of frequencies. The resonant frequency of the noise radiating element is tuned by an expandable ring embedded in the noise radiating element. Excitation of the ring causes expansion or contraction of the ring, thereby varying the stress in the noise radiating element. The ring is actuated by a controller which receives input of a feedback signal proportional to displacement of the noise radiating element and a signal corresponding to the blade passage frequency of the engine's fan. In response, the controller determines a control signal which is sent to the ring, causing the ring to expand or contract. Instead of a single ring embedded in the noise radiating panel, a first expandable ring can be bonded to one side of the noise radiating element, and a second expandable ring can be bonded to the other side.

Radiation Protection, Safety and Security Issues in Ghana.

PubMed

Boadu, Mary; Emi-Reynolds, Geoffrey; Amoako, Joseph Kwabena; Akrobortu, Emmanuel; Hasford, Francis

2016-11-01

Although the use of radioisotopes in Ghana began in 1952, the Radiation Protection Board of Ghana was established in 1993 and served as the national competent authority for authorization and inspection of practices and activities involving radiation sources until 2015. The law has been superseded by an Act of Parliament, Act 895 of 2015, mandating the Nuclear Regulatory Authority of Ghana to take charge of the regulation of radiation sources and their applications. The Radiation Protection Institute in Ghana provided technical support to the regulatory authority. Regulatory and service activities that were undertaken by the Institute include issuance of permits for handling of a radiation sources, authorization and inspection of radiation sources, radiation safety assessment, safety assessment of cellular signal towers, and calibration of radiation-emitting equipment. Practices and activities involving application of radiation are brought under regulatory control in the country through supervision by the national competent authority.

10 CFR 835.401 - General requirements.

Code of Federal Regulations, 2010 CFR

2010-01-01

... DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Monitoring of Individuals and Areas § 835.401 General... engineered and administrative controls in containing radioactive material and reducing radiation exposure; and (6) Identify and control potential sources of individual exposure to radiation and/or radioactive...

10 CFR 835.401 - General requirements.

Code of Federal Regulations, 2013 CFR

2013-01-01

... DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Monitoring of Individuals and Areas § 835.401 General... engineered and administrative controls in containing radioactive material and reducing radiation exposure; and (6) Identify and control potential sources of individual exposure to radiation and/or radioactive...

10 CFR 835.401 - General requirements.

Code of Federal Regulations, 2012 CFR

2012-01-01

... DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Monitoring of Individuals and Areas § 835.401 General... engineered and administrative controls in containing radioactive material and reducing radiation exposure; and (6) Identify and control potential sources of individual exposure to radiation and/or radioactive...

10 CFR 835.401 - General requirements.

Code of Federal Regulations, 2011 CFR

2011-01-01

... DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Monitoring of Individuals and Areas § 835.401 General... engineered and administrative controls in containing radioactive material and reducing radiation exposure; and (6) Identify and control potential sources of individual exposure to radiation and/or radioactive...

10 CFR 835.401 - General requirements.

Code of Federal Regulations, 2014 CFR

2014-01-01

... DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Monitoring of Individuals and Areas § 835.401 General... engineered and administrative controls in containing radioactive material and reducing radiation exposure; and (6) Identify and control potential sources of individual exposure to radiation and/or radioactive...

Active noise control using noise source having adaptive resonant frequency tuning through stiffness variation

NASA Technical Reports Server (NTRS)

Rajiyah, Harindra (Inventor); Hedeen, Robert A. (Inventor); Pla, Frederic G. (Inventor); Renshaw, Anthony A. (Inventor)

1995-01-01

A noise source for an aircraft engine active noise cancellation system in which the resonant frequency of a noise radiating element is tuned to permit noise cancellation over a wide range of frequencies. The resonant frequency of the noise radiating element is tuned by a plurality of force transmitting mechanisms which contact the noise radiating element. Each one of the force transmitting mechanisms includes an expandable element and a spring in contact with the noise radiating element so that excitation of the element varies the spring force applied to the noise radiating element. The elements are actuated by a controller which receives input of a signal proportional to displacement of the noise radiating element and a signal corresponding to the blade passage frequency of the engine's fan. In response, the controller determines a control signal which is sent to the elements and causes the spring force applied to the noise radiating element to be varied. The force transmitting mechanisms can be arranged to either produce bending or linear stiffness variations in the noise radiating element.

X-ray source safety shutter

DOEpatents

Robinet, McLouis

1977-05-31

An apparatus is provided for controlling the activation of a high energy radiation source having a shutter. The apparatus includes magnets and magnetically responsive switches appropriately placed and interconnected so that only with the shutter and other parts of the source in proper position can safe emission of radiation out an open shutter occur.

System for inspecting large size structural components

DOEpatents

Birks, Albert S.; Skorpik, James R.

1990-01-01

The present invention relates to a system for inspecting large scale structural components such as concrete walls or the like. The system includes a mobile gamma radiation source and a mobile gamma radiation detector. The source and detector are constructed and arranged for simultaneous movement along parallel paths in alignment with one another on opposite sides of a structural component being inspected. A control system provides signals which coordinate the movements of the source and detector and receives and records the radiation level data developed by the detector as a function of source and detector positions. The radiation level data is then analyzed to identify areas containing defects corresponding to unexpected variations in the radiation levels detected.

Active noise control using noise source having adaptive resonant frequency tuning through variable ring loading

NASA Technical Reports Server (NTRS)

Rajiyah, Harindra (Inventor); Pla, Frederic G. (Inventor); Hedeen, Robert A. (Inventor); Renshaw, Anthony A. (Inventor)

1995-01-01

A noise source for an aircraft engine active noise cancellation system in which the resonant frequency of noise radiating structure is tuned to permit noise cancellation over a wide range of frequencies. The resonant frequency of the noise radiating structure is tuned by a plurality of drivers arranged to contact the noise radiating structure. Excitation of the drivers causes expansion or contraction of the drivers, thereby varying the edge loading applied to the noise radiating structure. The drivers are actuated by a controller which receives input of a feedback signal proportional to displacement of the noise radiating element and a signal corresponding to the blade passage frequency of the engine's fan. In response, the controller determines a control signal which is sent to the drivers, causing them to expand or contract. The noise radiating structure may be either the outer shroud of the engine or a ring mounted flush with an inner wall of the shroud or disposed in the interior of the shroud.

Viability of Acremonium coenophialum in tall fescue seed after ionizing radiation treatments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bagegni, A.M.; Sleper, D.A.; Kerr, H.D.

Planting tall fescue (Festuca arundinacea Schreb.) seed free of the endophyte Acremonium coenophialum Morgan-Jones and Gams allows establishment of swards free of the fungus. Eradication of the fungal endophyte from infected tall fescue seeds containing 130 g kg{sup {minus}1} moisture using ionizing radiation was investigated. Three sources of radiation were used: gamma rays ({sup 60}Co source), neutron particles ({sup 252}Cf source), and a thermal neutron beam. The percent germination of tall fescue seeds among gamma doses did not differ significantly (P < 0.05) from the control treatment and did not show a significant negative response (R{sub 2} = 0.41) tomore » increasing levels of gamma radiation. At 250 Gy of gamma radiation, percent germination after 14 d was still > 90%. Percent seed germination of tall fescue and high levels of radiation were negatively correlated for both sources of neutrons. Gamma radiation was shown to reduce (P < 0.01) the percent of the viable endophyte to {approx} 10% of control. The {sup 252}Cf and thermal neutrons reduced the percent of tall fescue infected by the endophyte to {approx} 30% without deleterious effects on seed germination.« less

Control of excessive lead exposure in radiator repair workers.

PubMed

1991-03-01

In 1988, 83 automotive repair workers with blood lead levels (BLLs) greater than 25 micrograms/dL were reported to state health departments in the seven states that collaborated with CDC's National Institute for Occupational Safety and Health (NIOSH) in maintaining registries of elevated BLLs in adults. In 18 (22%) of these 83 persons, BLLs were greater than 50 micrograms/dL. Among automotive repair workers for whom a job category was specified, radiator repair work was the principal source of lead exposure. The major sources of exposure for radiator repair workers are lead fumes generated during soldering and lead dust produced during radiator cleaning. This report summarizes current BLL surveillance data for radiator repair workers and describes three control technologies that are effective in reducing lead exposures in radiator repair shops.

Increase in Efficiency of Use of Pedestrian Radiation Portal Monitors

NASA Astrophysics Data System (ADS)

Solovev, D. B.; Merkusheva, A. E.

2017-11-01

Most international airports in the world use radiation portal monitors (RPM) for primary radiation control organization. During the exploitation pedestrian radiation portal monitors operators (in the Russian Federation it is a special subdivision of customs officials) have certain problems related to the search of an ionizing radiation source causing the alarm signal of a radiation monitor. Radiation portal monitors at standard (factory) settings have to find out the illegal moving of the radioisotopes moved by physical persons passing through a controlled zone and having a steady radiation by the gamma or neutron channel. The problem is that recently the number of the ownerships who underwent treatment or medical diagnostics with the use of radio pharmaceuticals considerably increased, i.e,. ownerships represent such an ionizing radiation source. The operator of the radiation portal monitor has to define very quickly whether the ownership is a violator (takes unsolved radioisotopes illegally) or is just a patient of the clinic who underwent treatment/diagnostics with the use of radio pharmaceuticals. The research showing the radioisotopes which are most often used in the medical purposes are given in article, it is offered to use the new software developed by the authors allowing the operator of the radiation portal monitor to define the location of the ownership which has such ionizing radiation source by the activity of radiation similar to the radiation from radio pharmaceuticals.

Electromagnetic radiation from filamentary sources in the presence of axially magnetized cylindrical plasma scatterers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Es’kin, V. A.; Ivoninsky, A. V.; Kudrin, A. V., E-mail: kud@rf.unn.ru

Electromagnetic radiation from filamentary electric-dipole and magnetic-current sources of infinite length in the presence of gyrotropic cylindrical scatterers in the surrounding free space is studied. The scatterers are assumed to be infinitely long, axially magnetized circular plasma columns parallel to the axis of the filamentary source. The field and the radiation pattern of each source are calculated in the case where the source frequency is equal to one of the surface plasmon resonance frequencies of the cylindrical scatterers. It is shown that the presence of even a single resonant magnetized plasma scatterer of small electrical radius or a few suchmore » scatterers significantly affects the total fields of the filamentary sources, so that their radiation patterns become essentially different from those in the absence of scatterers or the presence of isotropic scatterers of the same shape and size. It is concluded that the radiation characteristics of the considered sources can efficiently be controlled using their resonance interaction with the neighboring gyrotropic scatterers.« less

The Integrated Radiation Mapper Assistant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carlton, R.E.; Tripp, L.R.

1995-03-01

The Integrated Radiation Mapper Assistant (IRMA) system combines state-of-the-art radiation sensors and microprocessor based analysis techniques to perform radiation surveys. Control of the survey function is from a control station located outside the radiation thus reducing time spent in radiation areas performing radiation surveys. The system consists of a directional radiation sensor, a laser range finder, two area radiation sensors, and a video camera mounted on a pan and tilt platform. THis sensor package is deployable on a remotely operated vehicle. The outputs of the system are radiation intensity maps identifying both radiation source intensities and radiation levels throughout themore » room being surveyed. After completion of the survey, the data can be removed from the control station computer for further analysis or archiving.« less

Distributed optimization system and method

DOEpatents

Hurtado, John E.; Dohrmann, Clark R.; Robinett, III, Rush D.

2003-06-10

A search system and method for controlling multiple agents to optimize an objective using distributed sensing and cooperative control. The search agent can be one or more physical agents, such as a robot, and can be software agents for searching cyberspace. The objective can be: chemical sources, temperature sources, radiation sources, light sources, evaders, trespassers, explosive sources, time dependent sources, time independent sources, function surfaces, maximization points, minimization points, and optimal control of a system such as a communication system, an economy, a crane, and a multi-processor computer.

Distributed Optimization System

DOEpatents

Hurtado, John E.; Dohrmann, Clark R.; Robinett, III, Rush D.

2004-11-30

A search system and method for controlling multiple agents to optimize an objective using distributed sensing and cooperative control. The search agent can be one or more physical agents, such as a robot, and can be software agents for searching cyberspace. The objective can be: chemical sources, temperature sources, radiation sources, light sources, evaders, trespassers, explosive sources, time dependent sources, time independent sources, function surfaces, maximization points, minimization points, and optimal control of a system such as a communication system, an economy, a crane, and a multi-processor computer.

Remote Sensing and Monitoring of Earthen Flood-Control Structures

DTIC Science & Technology

2017-07-01

The source of energy in passive techniques is derived from incident solar radiation or sunlight that reacts with the atmosphere, hydrosphere, and...the energy reflected or emitted from the earth’s surface. The source of energy in passive techniques involves incident solar radiation or sunlight... solar radiation is reflected back into the atmosphere, or where heat energy is emitted from the earth’s surface. As shown by Figure 2-3, certain regions

Laser-controlled optical transconductance varistor system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nguyen, Hoang T.; Stuart, Brent C.

2017-07-11

An optical transconductance varistor system having a modulated radiation source configured to provide modulated stimulus, a wavelength converter operably connected to the modulated radiation source to produce a modulated stimulus having a predetermined wavelength, and a wide bandgap semiconductor photoconductive material in contact between two electrodes. The photoconductive material is operably coupled, such as by a beam transport module, to receive the modulated stimulus having the predetermined wavelength to control a current flowing through the photoconductive material when a voltage potential is present across the electrodes.

10 CFR 835.1202 - Accountable sealed radioactive sources.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 4 2010-01-01 2010-01-01 false Accountable sealed radioactive sources. 835.1202 Section 835.1202 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Sealed Radioactive Source Control § 835.1202 Accountable sealed radioactive sources. (a) Each accountable sealed radioactive source...

10 CFR 835.1202 - Accountable sealed radioactive sources.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 4 2013-01-01 2013-01-01 false Accountable sealed radioactive sources. 835.1202 Section 835.1202 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Sealed Radioactive Source Control § 835.1202 Accountable sealed radioactive sources. (a) Each accountable sealed radioactive source...

10 CFR 835.1202 - Accountable sealed radioactive sources.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 4 2012-01-01 2012-01-01 false Accountable sealed radioactive sources. 835.1202 Section 835.1202 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Sealed Radioactive Source Control § 835.1202 Accountable sealed radioactive sources. (a) Each accountable sealed radioactive source...

10 CFR 835.1202 - Accountable sealed radioactive sources.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 4 2011-01-01 2011-01-01 false Accountable sealed radioactive sources. 835.1202 Section 835.1202 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Sealed Radioactive Source Control § 835.1202 Accountable sealed radioactive sources. (a) Each accountable sealed radioactive source...

10 CFR 835.1202 - Accountable sealed radioactive sources.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 4 2014-01-01 2014-01-01 false Accountable sealed radioactive sources. 835.1202 Section 835.1202 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Sealed Radioactive Source Control § 835.1202 Accountable sealed radioactive sources. (a) Each accountable sealed radioactive source...

Noise control using a plate radiator and an acoustic resonator

NASA Technical Reports Server (NTRS)

Pla, Frederic G. (Inventor)

1996-01-01

An active noise control subassembly for reducing noise caused by a source (such as an aircraft engine) independent of the subassembly. A noise radiating panel is bendably vibratable to generate a panel noise canceling at least a portion of the source noise. A piezoceramic actuator plate is connected to the panel. A front plate is spaced apart from the panel and the first plate, is positioned generally between the source noise and the panel, and has a sound exit port. A first pair of spaced-apart side walls each generally abut the panel and the front plate so as to generally enclose a front cavity to define a resonator.

Efforts to reduce exposure at Japanese PWRs: CVCS improvement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Terada, Ryosuke

1995-03-01

Many reports have been focused on the reduction of radiation sources and related occupational exposures. The radiation sources mainly consist of corrosion products. Radiation dose rate is determined by the amount of the activated corrosion products on the surface of the primary loop components of Pressurized Water Reactor (PWR) plants. Therefore, reducing the amount of the corrosion product will contribute to the reduction of occupational exposures. In order to reduce the corrosion products, Chemical and Volume Control System (CVCS) has been improved in Japanese PWRs as follows: (a) Cation Bed Demineralizer Flowrate Control; (b) Hydrogen Peroxide Injection System; (c) Purificationmore » Flowrate During Plant Shutdown; (d) Fine Mesh Filters Upstream of Mixed Bed Demineralizers.« less

Radiation efficiency of earthquake sources at different hierarchical levels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kocharyan, G. G., E-mail: gevorgkidg@mail.ru; Moscow Institute of Physics and Technology

Such factors as earthquake size and its mechanism define common trends in alteration of radiation efficiency. The macroscopic parameter that controls the efficiency of a seismic source is stiffness of fault or fracture. The regularities of this parameter alteration with scale define several hierarchical levels, within which earthquake characteristics obey different laws. Small variations of physical and mechanical properties of the fault principal slip zone can lead to dramatic differences both in the amplitude of released stress and in the amount of radiated energy.

21 CFR 179.21 - Sources of radiation used for inspection of food, for inspection of packaged food, and for...

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sources of radiation used for inspection of food, for inspection of packaged food, and for controlling food processing. 179.21 Section 179.21 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) IRRADIATION IN...

Examples for the importance of radiophysical measurements in clinical phototherapy.

PubMed

Schneider, Lars Alexander; Wlaschek, Meinhard; Dissemond, Joachim; Scharffetter-Kochanek, Karin

2007-05-01

Optimal UV therapy requires regular surveillance of the variables that influence therapeutic success. In daily practice, phototherapy equipment is often operated with an attitude of "autocontrol." This implies that thorough control measurements of the emission spectra and calibration of UV fluences are not routinely performed. For both quality control and patient safety, it is essential to regularly check whether a UV source is providing the right target spectrum with the correct dose to the skin. We have exemplarily taken three UV sources currently used in clinical practice and performed radiophysical measurements, i. e. determined emission spectra, radiation output and correctness of dose calculation. All three sources revealed either a largely inhomogeneous distribution pattern of radiation intensity, variation of radiation intensity over time or insufficient filtering of the UV lamp emission spectrum. Furthermore the dose calculation procedures had to be revised because of significant differences between the estimated and the administered UV doses. Radiophysical measurement of all UV-equipment in clinical use is a simple and effective way to improve the safety and reliability of phototherapy. Such measurements help to uncover technical flaws in radiation sources and prevent unnecessary side effects and UV exposure risks for the patient.

A review on natural background radiation

PubMed Central

Shahbazi-Gahrouei, Daryoush; Gholami, Mehrdad; Setayandeh, Samaneh

2013-01-01

The world is naturally radioactive and approximately 82% of human-absorbed radiation doses, which are out of control, arise from natural sources such as cosmic, terrestrial, and exposure from inhalation or intake radiation sources. In recent years, several international studies have been carried out, which have reported different values regarding the effect of background radiation on human health. Gamma radiation emitted from natural sources (background radiation) is largely due to primordial radionuclides, mainly 232Th and 238U series, and their decay products, as well as 40K, which exist at trace levels in the earth's crust. Their concentrations in soil, sands, and rocks depend on the local geology of each region in the world. Naturally occurring radioactive materials generally contain terrestrial-origin radionuclides, left over since the creation of the earth. In addition, the existence of some springs and quarries increases the dose rate of background radiation in some regions that are known as high level background radiation regions. The type of building materials used in houses can also affect the dose rate of background radiations. The present review article was carried out to consider all of the natural radiations, including cosmic, terrestrial, and food radiation. PMID:24223380

Active Control of Fan Noise-Feasibility Study. Volume 2: Canceling Noise Source-Design of an Acoustic Plate Radiator Using Piezoceramic Actuators

NASA Technical Reports Server (NTRS)

Pla, F. G.; Rajiyah, H.

1995-01-01

The feasibility of using acoustic plate radiators powered by piezoceramic thin sheets as canceling sources for active control of aircraft engine fan noise is demonstrated. Analytical and numerical models of actuated beams and plates are developed and validated. An optimization study is performed to identify the optimum combination of design parameters that maximizes the plate volume velocity for a given resonance frequency. Fifteen plates with various plate and actuator sizes, thicknesses, and bonding layers were fabricated and tested using results from the optimization study. A maximum equivalent piston displacement of 0.39 mm was achieved with the optimized plate samples tested with only one actuator powered, corresponding to a plate deflection at the center of over 1 millimeter. This is very close to the deflection required for a full size engine application and represents a 160-fold improvement over previous work. Experimental results further show that performance is limited by the critical stress of the piezoceramic actuator and bonding layer rather than by the maximum moment available from the actuator. Design enhancements are described in detail that will lead to a flight-worthy acoustic plate radiator by minimizing actuator tensile stresses and reducing nonlinear effects. Finally, several adaptive tuning methods designed to increase the bandwidth of acoustic plate radiators are analyzed including passive, active, and semi-active approaches. The back chamber pressurization and volume variation methods are investigated experimentally and shown to be simple and effective ways to obtain substantial control over the resonance frequency of a plate radiator. This study shows that piezoceramic-based plate radiators can be a viable acoustic source for active control of aircraft engine fan noise.

Radiation Effects: Overview for Space Environment Specialists

NASA Technical Reports Server (NTRS)

Ladbury, Ray

2017-01-01

Radiation Hardness Assurance (RHA) methodologies need to evolve to capitalize on the increased flexibility introduced by new models of space radiation environments. This presentation examines the characteristics of various radiation threats, the sources of error that RHA methodologies seek to control and the contributions of environment models to those errors. The influence of trends in microelectronic device technology is also considered.

Demonstration and development of control mechanism for radioactive sources in Saudi Arabia

NASA Astrophysics Data System (ADS)

Al-Kheliewi, A. S.

2012-06-01

Saudi Arabia have no nuclear industry. Nevertheless, many radioactive sources, for different purposes, have been used in the country. There is upswing in the number of companies that recruit nuclear technology in their daily work. The National Center for Radiation Protection (NCRP) takes the full commitment and responsibility for monitoring and regulating the movement of radioactive sources in the country. NCRP issues the licenses for import, export, and use of radioactive sources. It, also, protects the country from any trespassing radiation through a sizable net of early warning and radiation monitoring stations along the borders of Saudi Arabia. This paper talks about the procedures of licensing, importing, exporting of radioactive sources. It, also, sheds light on types of implementing radioactive sources in different practices encompass medicine, industry, research. The NCRP has established an electronic web site to ease the communication with all users in the country. This site is yet in the experimental stage.

Radiation protection and instrumentation

NASA Technical Reports Server (NTRS)

Bailey, J. V.

1975-01-01

Radiation was found not to be an operational problem during the Apollo program. Doses received by the crewmen of Apollo missions 7 through 17 were small because no major solar-particle events occurred during those missions. One small event was detected by a radiation sensor outside the Apollo 12 spacecraft, but no increase in radiation dose to the crewmen inside the spacecraft was detected. Radiation protection for the Apollo program was focused on both the peculiarities of the natural space radiation environment and the increased prevalence of manmade radiation sources on the ground and onboard the spacecraft. Radiation-exposure risks to crewmen were assessed and balanced against mission gain to determine mission constraints. Operational radiation evaluation required specially designed radiation detection systems onboard the spacecraft in addition to the use of satellite data, solar observatory support, and other liaison. Control and management of radioactive sources and radiation-generating equipment was important in minimizing radiation exposure of ground-support personnel, researchers, and the Apollo flight and backup crewmen.

Development of a hemispherical rotational modulation collimator system for imaging spatial distribution of radiation sources

NASA Astrophysics Data System (ADS)

Na, M.; Lee, S.; Kim, G.; Kim, H. S.; Rho, J.; Ok, J. G.

2017-12-01

Detecting and mapping the spatial distribution of radioactive materials is of great importance for environmental and security issues. We design and present a novel hemispherical rotational modulation collimator (H-RMC) system which can visualize the location of the radiation source by collecting signals from incident rays that go through collimator masks. The H-RMC system comprises a servo motor-controlled rotating module and a hollow heavy-metallic hemisphere with slits/slats equally spaced with the same angle subtended from the main axis. In addition, we also designed an auxiliary instrument to test the imaging performance of the H-RMC system, comprising a high-precision x- and y-axis staging station on which one can mount radiation sources of various shapes. We fabricated the H-RMC system which can be operated in a fully-automated fashion through the computer-based controller, and verify the accuracy and reproducibility of the system by measuring the rotational and linear positions with respect to the programmed values. Our H-RMC system may provide a pivotal tool for spatial radiation imaging with high reliability and accuracy.

Survey of instrumentation for environmental monitoring: major update. Volume 3. Radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1979-09-01

This is the third volume of a four-volume (seven-part) series, the culmination of a comprehensive survey of instrumentation for environmental monitoring. Consideration is given to instruments and techniques presently in use and to those developed for other purposes but having possible applications to radiation monitoring. The results of the survey are given as descriptions of the physical and operating characteristics of available instruments, critical comparisons among instrumentation methods, and recommendations of promising methodology and development of new instrumentation. Information is also given regarding the pollutants to be monitored, their characteristics and forms, their sources and pathways, their effects on themore » ecosystem, and the means of controlling them through process and regulatory controls. The discussion is presented under sections entitled radiation sources; instrumentation: by type of radiation or instrument type; and, instrumentation for specific radionuclides. (JGB)« less

Radiation exposure control from the application of nuclear gauges in the mining industry in Ghana.

PubMed

Faanu, A; Darko, E O; Awudu, A R; Schandorf, C; Emi-Reynolds, G; Yeboah, J; Glover, E T; Kattah, V K

2010-05-01

The use of nuclear gauges for process control and elemental analysis in the mining industry in Ghana, West Africa, is wide spread and on the increase in recent times. The Ghana Radiation Protection Board regulates nuclear gauges through a system of notification and authorization by registration or licensing, inspection, and enforcement. Safety assessments for authorization and enforcement have been established to ensure the safety and security of radiation sources as well as protection of workers and the general public. Appropriate training of mine staff is part of the efforts to develop the necessary awareness about the safety and security of radiation sources. The knowledge and skills acquired will ensure the required protection and safety at the workplaces. Doses received by workers monitored over a period between 1998 and 2007 are well below the annual dose limit of 20 mSv recommended by the International Commission on Radiological Protection.

NCRP Program Area Committee 2: Operational Radiation Safety

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pryor, Kathryn H.; Goldin, Eric M.

2016-02-29

Program Area Committee 2 of the National Council on Radiation Protection and Measurements provides guidance for radiation safety in occupational settings in a variety of industries and activities. The committee completed three reports in recent years covering recommendations for the development and administration of radiation safety programs for smaller educational institutions, requirements for self-assessment programs that improve radiation safety and identify and correct deficiencies, and a comprehensive process for effective investigation of radiological incidents. Ongoing work includes a report on sealed radioactive source controls and oversight of a report on radioactive nanomaterials focusing on gaps within current radiation safety programs.more » Future efforts may deal with operational radiation safety programs in fields such as the safe use of handheld and portable X-Ray fluorescence analyzers, occupational airborne radioactive contamination, unsealed radioactive sources, or industrial accelerators.« less

Deterministic control of radiative processes by shaping the mode field

NASA Astrophysics Data System (ADS)

Pellegrino, D.; Pagliano, F.; Genco, A.; Petruzzella, M.; van Otten, F. W.; Fiore, A.

2018-04-01

Quantum dots (QDs) interacting with confined light fields in photonic crystal cavities represent a scalable light source for the generation of single photons and laser radiation in the solid-state platform. The complete control of light-matter interaction in these sources is needed to fully exploit their potential, but it has been challenging due to the small length scales involved. In this work, we experimentally demonstrate the control of the radiative interaction between InAs QDs and one mode of three coupled nanocavities. By non-locally moulding the mode field experienced by the QDs inside one of the cavities, we are able to deterministically tune, and even inhibit, the spontaneous emission into the mode. The presented method will enable the real-time switching of Rabi oscillations, the shaping of the temporal waveform of single photons, and the implementation of unexplored nanolaser modulation schemes.

Tritium-powered radiation sensor network

NASA Astrophysics Data System (ADS)

Litz, Marc S.; Russo, Johnny A.; Katsis, Dimos

2016-05-01

Isotope power supplies offer long-lived (100 years using 63Ni), low-power energy sources, enabling sensors or communications nodes for the lifetime of infrastructure. A tritium beta-source (12.5-year half-life) encapsulated in a phosphor-lined vial couples directly to a photovoltaic (PV) to generate a trickle current into an electrical load. An inexpensive design is described using commercial-of-the-shelf (COTS) components that generate 100 μWe for nextgeneration compact electronics/sensors. A matched radiation sensor has been built for long-duration missions utilizing microprocessor-controlled sleep modes, low-power electronic components, and a passive interrupt driven environmental wake-up. The low-power early-warning radiation detector network and isotope power source enables no-maintenance mission lifetimes.

Introduction to meteorological measurements and data handling for solar energy applications. Task IV. Development of an isolation handbook and instrument package

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

The following are covered: the Sun and its radiation, solar radiation and atmospheric interaction, solar radiation measurement methods, spectral irradiance measurements of natural sources, the measurement of infrared radiation, the measurement of circumsolar radiation, some empirical properties of solar radiation and related parameters, duration of sunshine, and meteorological variables related to solar energy. Included in appendices are manufacturers and distributors of solar radiation measuring instruments and an approximate method for quality control of solar radiation instruments. (MHR)

Collaboration and Commitment to Sealed Source Safety, Security, and Disposition - 13627

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jennison, Meaghan; Martin, David W.

2013-07-01

EnergySolutions, the Division of Radiation Control at the Utah Department of Environmental Quality (UDEQ), the Conference of Radiation Control Program Directors (CRCPD), and the Department of Energy's Global Threat Reduction Initiative (GTRI) are collaborating on a truly innovative effort to expand opportunities for cost-effective sealed source disposal. These entities have developed a first-of-its-kind initiative to dispose of certain sealed sources at the EnergySolutions disposal facility near Clive, Utah, which normally cannot accept sealed sources of any type. This creative and collaborative effort to improve radiation health, safety, and security exemplifies the spirit and commitment represented by the Richard S. Hodes,more » M.D. Honor Lecture Award, which is presented annually at the Waste Management Symposia by the Southeast Compact Commission to encourage environmental professionals and political leaders to develop innovative approaches to waste management in the United States. The participants in the collaborative initiative are honored to receive special recognition for their efforts thus far. They also recognize that the hard work remains to be done. (authors)« less

21 CFR 179.21 - Sources of radiation used for inspection of food, for inspection of packaged food, and for...

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sources of radiation used for inspection of food, for inspection of packaged food, and for controlling food processing. 179.21 Section 179.21 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) IRRADIATION IN THE...

Infrared Radiation Filament And Metnod Of Manufacture

DOEpatents

Johnson, Edward A.

1998-11-17

An improved IR radiation source is provided by the invention. A radiation filament has a textured surface produced by seeded ion bombardment of a metal foil which is cut to a serpentine shape and mounted in a windowed housing. Specific ion bombardment texturing techniques tune the surface to maximize emissions in the desired wavelength range and to limit emissions outside that narrow range, particularly at longer wavelengths. A combination of filament surface texture, thickness, material, shape and power circuit feedback control produce wavelength controlled and efficient radiation at much lower power requirements than devices of the prior art.

[Radiative and hygienic certification in Armed Forces, problems of its implementation and ways of perfection].

PubMed

Rusakov, V N; Cherkashin, A V; Shishkanov, A P; Ian'shin, L A; Gracheva, T N

2010-12-01

Radiative and hygienic passportization is one of the most actual pattern of socio and hygienic monitoring in Armed Forces. Radiative and hygienic passport is the main document which characterizes the safety control in military unit and uses the sources of ionizing radiation. Sanitary and epidemiologic institutions were imputed to control the formation of radiative and hygienic passports, analysis and generalization of its data, formation of conclusions about the condition of radiation security in the military units. According to radiative and hygienic passportization, which took place in 2009, the radiation security in the Armed Forces and organizations is satisfactory, but there are some problems of providing of radiation security of personnel under the professional and medical radiation. The salvation of its problems requires the effective work of official functionary of radiac object and institutions of state sanitary and epidemiological supervision in Armed Forces of Russian Federation.

Electronic modulation of infrared radiation in graphene plasmonic resonators.

PubMed

Brar, Victor W; Sherrott, Michelle C; Jang, Min Seok; Kim, Seyoon; Kim, Laura; Choi, Mansoo; Sweatlock, Luke A; Atwater, Harry A

2015-05-07

All matter at finite temperatures emits electromagnetic radiation due to the thermally induced motion of particles and quasiparticles. Dynamic control of this radiation could enable the design of novel infrared sources; however, the spectral characteristics of the radiated power are dictated by the electromagnetic energy density and emissivity, which are ordinarily fixed properties of the material and temperature. Here we experimentally demonstrate tunable electronic control of blackbody emission from graphene plasmonic resonators on a silicon nitride substrate. It is shown that the graphene resonators produce antenna-coupled blackbody radiation, which manifests as narrow spectral emission peaks in the mid-infrared. By continuously varying the nanoresonator carrier density, the frequency and intensity of these spectral features can be modulated via an electrostatic gate. This work opens the door for future devices that may control blackbody radiation at timescales beyond the limits of conventional thermo-optic modulation.

Demonstration and development of control mechanism for radioactive sources in Saudi Arabia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Kheliewi, A. S.

2012-06-06

Saudi Arabia have no nuclear industry. Nevertheless, many radioactive sources, for different purposes, have been used in the country. There is upswing in the number of companies that recruit nuclear technology in their daily work. The National Center for Radiation Protection (NCRP) takes the full commitment and responsibility for monitoring and regulating the movement of radioactive sources in the country. NCRP issues the licenses for import, export, and use of radioactive sources. It, also, protects the country from any trespassing radiation through a sizable net of early warning and radiation monitoring stations along the borders of Saudi Arabia. This papermore » talks about the procedures of licensing, importing, exporting of radioactive sources. It, also, sheds light on types of implementing radioactive sources in different practices encompass medicine, industry, research. The NCRP has established an electronic web site to ease the communication with all users in the country. This site is yet in the experimental stage.« less

Visible and near-infrared laser radiation in a biological tissue. A forward model for medical imaging by optical tomography.

PubMed

Trabelsi, H; Gantri, M; Sediki, E

2010-01-01

We present a numerical model for the study of a general, two-dimensional, time-dependent, laser radiation transfer problem in a biological tissue. The model is suitable for many situations, especially when the external laser source is pulsed or continuous. We used a control volume discrete-ordinate method associated with an implicit, three-level, second-order, time-differencing scheme. In medical imaging by laser techniques, this could be an optical tomography forward model. We considered a very thin rectangular biological tissue-like medium submitted to a visible or a near-infrared laser source. Different cases were treated numerically. The source was assumed to be monochromatic and collimated. We used either a continuous source or a short-pulsed source. The transmitted radiance was computed in detector points on the boundaries. Also, the distribution of the internal radiation intensity for different instants is presented. According to the source type, we examined either the steady-state response or the transient response of the medium. First, our model was validated by experimental results from the literature for a homogeneous biological tissue. The space and angular grid independency of our results is shown. Next, the proposed model was used to study changes in transmitted radiation for a homogeneous background medium in which were imbedded two heterogeneous objects. As a last investigation, we studied a multilayered biological tissue. We simulated near-infrared radiation in human skin, fat and muscle. Some results concerning the effects of fat thickness and positions of the detector source on the reflected radiation are presented.

10 CFR 50.67 - Accident source term.

Code of Federal Regulations, 2014 CFR

2014-01-01

... occupancy of the control room under accident conditions without personnel receiving radiation exposures in... 10 Energy 1 2014-01-01 2014-01-01 false Accident source term. 50.67 Section 50.67 Energy NUCLEAR... Conditions of Licenses and Construction Permits § 50.67 Accident source term. (a) Applicability. The...

10 CFR 50.67 - Accident source term.

Code of Federal Regulations, 2012 CFR

2012-01-01

... occupancy of the control room under accident conditions without personnel receiving radiation exposures in... 10 Energy 1 2012-01-01 2012-01-01 false Accident source term. 50.67 Section 50.67 Energy NUCLEAR... Conditions of Licenses and Construction Permits § 50.67 Accident source term. (a) Applicability. The...

10 CFR 50.67 - Accident source term.

Code of Federal Regulations, 2010 CFR

2010-01-01

... occupancy of the control room under accident conditions without personnel receiving radiation exposures in... 10 Energy 1 2010-01-01 2010-01-01 false Accident source term. 50.67 Section 50.67 Energy NUCLEAR... Conditions of Licenses and Construction Permits § 50.67 Accident source term. (a) Applicability. The...

10 CFR 50.67 - Accident source term.

Code of Federal Regulations, 2013 CFR

2013-01-01

... occupancy of the control room under accident conditions without personnel receiving radiation exposures in... 10 Energy 1 2013-01-01 2013-01-01 false Accident source term. 50.67 Section 50.67 Energy NUCLEAR... Conditions of Licenses and Construction Permits § 50.67 Accident source term. (a) Applicability. The...

10 CFR 50.67 - Accident source term.

Code of Federal Regulations, 2011 CFR

2011-01-01

... occupancy of the control room under accident conditions without personnel receiving radiation exposures in... 10 Energy 1 2011-01-01 2011-01-01 false Accident source term. 50.67 Section 50.67 Energy NUCLEAR... Conditions of Licenses and Construction Permits § 50.67 Accident source term. (a) Applicability. The...

Genotoxicity and carcinogenicity of the light emitted by artificial illumination systems.

PubMed

De Flora, Silvio

2013-03-01

The light delivered by artificial illumination systems, and in particular by halogen quartz bulbs, contains UVA, UVB, and UVC radiation, is genotoxic to both bacterial and human cells and is potently carcinogenic to hairless mice. Since IARC has classified UV radiation in Group 1, any source of UV light poses a carcinogenic hazard to humans. Suitable regulations would be needed in order to control the safety of the light emitted by artificial light sources.

Accuracy control in Monte Carlo radiative calculations

NASA Technical Reports Server (NTRS)

Almazan, P. Planas

1993-01-01

The general accuracy law that rules the Monte Carlo, ray-tracing algorithms used commonly for the calculation of the radiative entities in the thermal analysis of spacecraft are presented. These entities involve transfer of radiative energy either from a single source to a target (e.g., the configuration factors). or from several sources to a target (e.g., the absorbed heat fluxes). In fact, the former is just a particular case of the latter. The accuracy model is later applied to the calculation of some specific radiative entities. Furthermore, some issues related to the implementation of such a model in a software tool are discussed. Although only the relative error is considered through the discussion, similar results can be derived for the absolute error.

Sound reduction by metamaterial-based acoustic enclosure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yao, Shanshan; Li, Pei; Zhou, Xiaoming

In many practical systems, acoustic radiation control on noise sources contained within a finite volume by an acoustic enclosure is of great importance, but difficult to be accomplished at low frequencies due to the enhanced acoustic-structure interaction. In this work, we propose to use acoustic metamaterials as the enclosure to efficiently reduce sound radiation at their negative-mass frequencies. Based on a circularly-shaped metamaterial model, sound radiation properties by either central or eccentric sources are analyzed by numerical simulations for structured metamaterials. The parametric analyses demonstrate that the barrier thickness, the cavity size, the source type, and the eccentricity of themore » source have a profound effect on the sound reduction. It is found that increasing the thickness of the metamaterial barrier is an efficient approach to achieve large sound reduction over the negative-mass frequencies. These results are helpful in designing highly efficient acoustic enclosures for blockage of sound in low frequencies.« less

EVALUATION OF BARRIERS TO THE USE OF RADIATION-CURED COATINGS IN SCREEN PRINTING

EPA Science Inventory

The report gives results of an evaluation of barriers to the use of radiation-cured coatings in screen printing. In support of the Source Reduction Review Project (SRRP), maximum achievable control technology (MACT) standards development, and the Pollution Prevention Act, EPA is ...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zohar, S.; Sterbinsky, G. E.

Here, we propose an experimental technique for extending feedback compensation of dissipative radiation used in nuclear magnetic resonance (NMR) to encompass ferromagnetic resonance (FMR). This method uses a balanced microwave power detector whose output is phase shifted π/2, amplified, and fed back to drive precession. Using classical control theory, we predict an electronically controllable narrowing of field swept FMR line-widths. This technique is predicted to compensate other sources of spin dissipation in addition to radiative loss.

Analysis and control of computer cooling fan noise

NASA Astrophysics Data System (ADS)

Wong, Kam

This thesis is divided into three parts: the study of the source mechanisms and their separation, passive noise control, and active noise control. The mechanisms of noise radiated by a typical computer cooling fan is investigated both theoretically and experimentally focusing on the dominant rotor-stator interaction. The unsteady force generated by the aerodynamic interaction between the rotor blades and struts is phase locked with the blade rotation and radiates tonal noise. Experimentally, synchronous averaging with the rotation signal extracts the tones made by the deterministic part of the rotor-strut interaction mechanism. This averaged signal is called the rotary noise. The difference between the overall noise and rotary noise is defined as random noise which is broadband in the spectrum. The deterministic tonal peaks are certainly more annoying than the broadband, so the suppression of the tones is the focus of this study. Based on the theoretical study of point force formulation, methods are devised to separate the noise radiated by the two components of drag and thrust forces on blades and struts. The source separation is also extended to the leading and higher order modes of the spinning pressure pattern. By using the original fan rotor and installing it in various casings, the noise sources of the original fan are decomposed into elementary sources through directivity measurements. Details of the acoustical directivity for the original fan and its various modifications are interpreted. For the sample fan, two common features account for most of the tonal noise radiated. The two features are the inlet flow distortion caused by the square fan casing, and the large strut carrying the electric wires for the motor. When the inlet bellmouth is installed and the large strut is trimmed down to size, a significant reduction of 12 dB in tonal sound power is achieved. These structural corrections constitute the passive noise control. However, the end product still features the leading mode drag noise. Further reduction of this noise is left to the active noise control. The feasibility of the active noise control technique is demonstrated for the cancellation of both thrust and drag noise radiated at their leading modes. An open loop, feed-forward system is used to maximize the simplicity of the rig in order to deliver an appropriate technology for a small ventilation fan. (Abstract shortened by UMI.)

Equipment for studying soils (in French)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Corossi, J.C.; Chanu, D.; Couchat, P.

1971-06-30

Equipment for studying soils is presented. It consists of a radiation source, a device for detecting radiation after its absorption or scattering by the soil under investigation, and a probe containing the source and detector. Means are provided for displacing the probe (in particular inside a well) and for measuring and determining the intensity of the radiation detected at various positions of the probe, or, that of a parameter dependent on the intensity. In addition, the equipment is provided with means for recording the results furnished by the measurement part and the parameters associated with each measurement together with meansmore » for automatically controlling a cycle, or, a series of cycles of successive measurement-recording operations, each, at least possessing a cortrol over the displacement part (this part displacing the probe through a predetermined distance), and a control over the measurement and recording parts. (FR)« less

Controlled injection using a channel pinch in a plasma-channel-guided laser wakefield accelerator

NASA Astrophysics Data System (ADS)

Liu, Jiaqi; Zhang, Zhijun; Liu, Jiansheng; Li, Wentao; Wang, Wentao; Yu, Changhai; Qi, Rong; Qin, Zhiyong; Fang, Ming; Wu, Ying; Feng, Ke; Ke, Lintong; Wang, Cheng; Li, Ruxin

2018-06-01

Plasma-channel-guided laser plasma accelerators make it possible to drive high-brilliance compact radiation sources and have high-energy physics applications. Achieving tunable internal injection of the electron beam (e beam) inside the plasma channel, which realizes a tunable radiation source, is a challenging method to extend such applications. In this paper, we propose the use of a channel pinch, which is designed as an initial reduction followed by an expansion of the channel radius along the plasma channel, to achieve internal controlled off-axis e beam injection in a channel-guided laser plasma accelerator. The off-axis injection is triggered by bubble deformation in the expansion region. The dynamics of the plasma wake is explored, and the trapping threshold is found to be reduced radially in the channel pinch. Simulation results show that the channel pinch not only triggers injection process localized at the pinch but also modulates the parameters of the e beam by adjusting its density profile, which can additionally accommodate a tunable radiation source via betatron oscillation.

First Test of Fan Active Noise Control (ANC) Completed

NASA Technical Reports Server (NTRS)

2005-01-01

With the advent of ultrahigh-bypass engines, the space available for passive acoustic treatment is becoming more limited, whereas noise regulations are becoming more stringent. Active noise control (ANC) holds promise as a solution to this problem. It uses secondary (added) noise sources to reduce or eliminate the offending noise radiation. The first active noise control test on the low-speed fan test bed was a General Electric Company system designed to control either the exhaust or inlet fan tone. This system consists of a "ring source," an induct array of error microphones, and a control computer. Fan tone noise propagates in a duct in the form of spinning waves. These waves are detected by the microphone array, and the computer identifies their spinning structure. The computer then controls the "ring source" to generate waves that have the same spinning structure and amplitude, but 180 out of phase with the fan noise. This computer generated tone cancels the fan tone before it radiates from the duct and is heard in the far field. The "ring source" used in these tests is a cylindrical array of 16 flat-plate acoustic radiators that are driven by thin piezoceramic sheets bonded to their back surfaces. The resulting source can produce spinning waves up to mode 7 at levels high enough to cancel the fan tone. The control software is flexible enough to work on spinning mode orders from -6 to 6. In this test, the fan was configured to produce a tone of order 6. The complete modal (spinning and radial) structure of the tones was measured with two builtin sets of rotating microphone rakes. These rakes provide a measurement of the system performance independent from the control system error microphones. In addition, the far-field noise was measured with a semicircular array of 28 microphones. This test represents the first in a series of tests that demonstrate different active noise control concepts, each on a progressively more complicated modal structure. The tests are in preparation for a demonstration on a flight-type engine.

What views and uses of radiation sources in the 21st century?

PubMed

Blix, H

2001-04-01

Considering that in 1899 neither biotechnology nor the electronic revolution were foreseen, some humility might be advisable when one looks into the crystal ball for the future role of radiation sources. In the past 50 years, nuclear medicine, nuclear weapons, and nuclear power have had a huge impact in the world. In the next 50 years, nuclear weapons may be phased out, nuclear power revived, and nuclear medicine may continue, especially for diagnostic purposes. Conflicts between great powers and blocks will no longer be about territorial or ideological domination but about trade, finance, information, and the environment and the weapons used will not be bombs but investments, credits, and control of information. Nuclear power-still based on fission-will be relaunched and get more uses, e.g., to propel ships, to produce heat for industry and for space heating, and perhaps to desalinate water. The public will be more at ease with radiation as it is better educated, as nuclear safety continuously improves and new types of nuclear power plants emerge, as waste sites fail to cause any problems, and as no other energy source is found to deliver so much energy at reasonable cost with negligible impact on climate and environment. One kilogram of oil corresponds to 4 kWh of electricity. One kilogram of uranium fuel corresponds to 50,000 kWh, and 1 kg of plutonium 6,000,000 kWh! In nuclear medicine, radiation may give way to other treatments as the understanding of cancer advances. On the other hand, the extreme ease with which sources of radiation can be identified is unmatched and likely to make them useful tools as tracers and markers in medicine-and other fields-for a long time. For certain uses--perhaps food irradiation--radiation sources, such as cobalt, may be replaced by accelerators which may be switched on and off at will. As more sources are used, registration and control of them must be made very effective around the whole world. Very high natural emissions of radon will continue to call for cautionary measures, but many other nonradiating substances will be identified as hazardous to health and call for vigorous intervention.

Bundled monocapillary optics

DOEpatents

Hirsch, Gregory

2002-01-01

A plurality of glass or metal wires are precisely etched to form the desired shape of the individual channels of the final polycapillary optic. This shape is created by carefully controlling the withdrawal speed of a group of wires from an etchant bath. The etched wires undergo a subsequent operation to create an extremely smooth surface. This surface is coated with a layer of material which is selected to maximize the reflectivity of the radiation being used. This reflective surface may be a single layer of material, or a multilayer coating for optimizing the reflectivity in a narrower wavelength interval. The collection of individual wires is assembled into a close-packed multi-wire bundle, and the wires are bonded together in a manner which preserves the close-pack configuration, irrespective of the local wire diameter. The initial wires are then removed by either a chemical etching procedure or mechanical force. In the case of chemical etching, the bundle is generally segmented by cutting a series of etching slots. Prior to removing the wire, the capillary array is typically bonded to a support substrate. The result of the process is a bundle of precisely oriented radiation-reflecting hollow channels. The capillary optic is used for efficiently collecting and redirecting the radiation from a source of radiation which could be the anode of an x-ray tube, a plasma source, the fluorescent radiation from an electron microprobe, a synchrotron radiation source, a reactor or spallation source of neutrons, or some other source.

A brief review of intermediate controlled nuclear syntheses (ICNS) without harmful radiations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lanjewar, R. B.

Hadronic mechanics gave birth to new magnecular fuels. The present day demand is of clean energy source that is cheap and abundant. Clean energy can be obtained by harnessing renewable energy sources like solar, wind etc. Nuclear energy conventionally produced by fission reactions emits hazardous radiation and radioactive waste. The requirements of clean and safe energy gets fulfilled by novel fuel that achieved by elevating the traditional quantum mechanics to hadronic mechanics and to hadronic chemistry. In the present paper, a comprehensive review on both the theoretical and experimental aspect of the Intermediate Controlled Nuclear Synthesis (ICNS) as developed bymore » Italian American Scientist Professor R. M. Santilli.« less

[Organization of monitoring of electromagnetic radiation in the urban environment].

PubMed

Savel'ev, S I; Dvoeglazova, S V; Koz'min, V A; Kochkin, D E; Begishev, M R

2008-01-01

The authors describe new current approaches to monitoring the environment, including the sources of electromagnetic radiation and noise. Electronic maps of the area under study are shown to be made, by constructing the isolines or distributing the actual levels of controlled factors. These current approaches to electromagnetic and acoustic monitoring make it possible to automate a process of measurements, to analyze the established situation, and to simplify the risk controlling methodology.

Apollo experience report: Protection against radiation

NASA Technical Reports Server (NTRS)

English, R. A.; Benson, R. E.; Bailey, J. V.; Barnes, C. M.

1973-01-01

Radiation protection problems on earth and in space are discussed. Flight through the Van Allen belts and into space beyond the geomagnetic shielding was recognized as hazardous before the advent of manned space flight. Specialized dosimetry systems were developed for use on the Apollo spacecraft, and systems for solar-particle-event warning and dose projection were devised. Radiation sources of manmade origin on board the Apollo spacecraft present additional problems. Methods applied to evaluate and control or avoid the various Apollo radiation hazards are discussed.

Development of an X-Ray Catheter Final Report CRADA No. TC-1265-96

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trebes, J.; Schlossberg, M.

2017-11-01

Toe goal of this CRADA project was to develop a catheter-based x-ray source to provide treatment of restenosis in arteries with a radiation source which can be precisely controlled and turned on and off at will.

On the acoustic radiation modes of compact regular polyhedral arrays of independent loudspeakers.

PubMed

Pasqual, Alexander Mattioli; Martin, Vincent

2011-09-01

Compact spherical loudspeaker arrays can be used to provide control over their directivity pattern. Usually, this is made by adjusting the gains of preprogrammed spatial filters corresponding to a finite set of spherical harmonics, or to the acoustic radiation modes of the loudspeaker array. Unlike the former, the latter are closely related to the radiation efficiency of the source and span the subspace of the directivities it can produce. However, the radiation modes depend on frequency for arbitrary distributions of transducers on the sphere, which yields complex directivity filters. This work focuses on the most common loudspeaker array configurations, those following the regular shape of the Platonic solids. It is shown that the radiation modes of these sources are frequency independent, and simple algebraic expressions are derived for their radiation efficiencies. In addition, since such modes are vibration patterns driven by electrical signals, the transduction mechanism of compact multichannel sources is also investigated, which is an important issue, especially if the transducers interact inside a shared cabinet. For Platonic solid loudspeakers, it is shown that the common enclosure does not lead to directivity filters that depend on frequency. © 2011 Acoustical Society of America

Factors controlling high-frequency radiation from extended ruptures

NASA Astrophysics Data System (ADS)

Beresnev, Igor A.

2017-09-01

Small-scale slip heterogeneity or variations in rupture velocity on the fault plane are often invoked to explain the high-frequency radiation from earthquakes. This view has no theoretical basis, which follows, for example, from the representation integral of elasticity, an exact solution for the radiated wave field. The Fourier transform, applied to the integral, shows that the seismic spectrum is fully controlled by that of the source time function, while the distribution of final slip and rupture acceleration/deceleration only contribute to directivity. This inference is corroborated by the precise numerical computation of the full radiated field from the representation integral. We compare calculated radiation from four finite-fault models: (1) uniform slip function with low slip velocity, (2) slip function spatially modulated by a sinusoidal function, (3) slip function spatially modulated by a sinusoidal function with random roughness added, and (4) uniform slip function with high slip velocity. The addition of "asperities," both regular and irregular, does not cause any systematic increase in the spectral level of high-frequency radiation, except for the creation of maxima due to constructive interference. On the other hand, an increase in the maximum rate of slip on the fault leads to highly amplified high frequencies, in accordance with the prediction on the basis of a simple point-source treatment of the fault. Hence, computations show that the temporal rate of slip, not the spatial heterogeneity on faults, is the predominant factor forming the high-frequency radiation and thus controlling the velocity and acceleration of the resulting ground motions.

Optical control of hard X-ray polarization by electron injection in a laser wakefield accelerator

PubMed Central

Schnell, Michael; Sävert, Alexander; Uschmann, Ingo; Reuter, Maria; Nicolai, Maria; Kämpfer, Tino; Landgraf, Björn; Jäckel, Oliver; Jansen, Oliver; Pukhov, Alexander; Kaluza, Malte Christoph; Spielmann, Christian

2013-01-01

Laser-plasma particle accelerators could provide more compact sources of high-energy radiation than conventional accelerators. Moreover, because they deliver radiation in femtosecond pulses, they could improve the time resolution of X-ray absorption techniques. Here we show that we can measure and control the polarization of ultra-short, broad-band keV photon pulses emitted from a laser-plasma-based betatron source. The electron trajectories and hence the polarization of the emitted X-rays are experimentally controlled by the pulse-front tilt of the driving laser pulses. Particle-in-cell simulations show that an asymmetric plasma wave can be driven by a tilted pulse front and a non-symmetric intensity distribution of the focal spot. Both lead to a notable off-axis electron injection followed by collective electron–betatron oscillations. We expect that our method for an all-optical steering is not only useful for plasma-based X-ray sources but also has significance for future laser-based particle accelerators. PMID:24026068

SU-E-T-103: Development and Implementation of Web Based Quality Control Software

DOE Office of Scientific and Technical Information (OSTI.GOV)

Studinski, R; Taylor, R; Angers, C

Purpose: Historically many radiation medicine programs have maintained their Quality Control (QC) test results in paper records or Microsoft Excel worksheets. Both these approaches represent significant logistical challenges, and are not predisposed to data review and approval. It has been our group's aim to develop and implement web based software designed not just to record and store QC data in a centralized database, but to provide scheduling and data review tools to help manage a radiation therapy clinics Equipment Quality control program. Methods: The software was written in the Python programming language using the Django web framework. In order tomore » promote collaboration and validation from other centres the code was made open source and is freely available to the public via an online source code repository. The code was written to provide a common user interface for data entry, formalize the review and approval process, and offer automated data trending and process control analysis of test results. Results: As of February 2014, our installation of QAtrack+ has 180 tests defined in its database and has collected ∼22 000 test results, all of which have been reviewed and approved by a physicist via QATrack+'s review tools. These results include records for quality control of Elekta accelerators, CT simulators, our brachytherapy programme, TomoTherapy and Cyberknife units. Currently at least 5 other centres are known to be running QAtrack+ clinically, forming the start of an international user community. Conclusion: QAtrack+ has proven to be an effective tool for collecting radiation therapy QC data, allowing for rapid review and trending of data for a wide variety of treatment units. As free and open source software, all source code, documentation and a bug tracker are available to the public at https://bitbucket.org/tohccmedphys/qatrackplus/.« less

Radiation dosimetry for quality control of food preservation and disinfestation

NASA Astrophysics Data System (ADS)

McLaughlin, W. L.; Miller, A.; Uribe, R. M.

In the use of x and gamma rays and scanned electron beams to extend the shelf life of food by delay of sprouting and ripening, killing of microbes, and control of insect population, quality assurance is provided by standardized radiation dosimetry. By strategic placement of calibrated dosimeters that are sufficiently stable and reproducible, it is possible to monitor minimum and maximum radiation absorbed dose levels and dose uniformity for a given processed foodstuff. The dosimetry procedure is especially important in the commisioning of a process and in making adjustments of process parameters (e.g. conveyor speed) to meet changes that occur in product and source parameters (e.g. bulk density and radiation spectrum). Routine dosimetry methods and certain corrections of dosimetry data may be selected for the radiations used in typical food processes.

Illumination system having a plurality of movable sources

DOEpatents

Sweatt, William C.; Kubiak, Glenn D.

2002-01-01

An illumination system includes several discharge sources that are multiplexed together to reduce the amount of debris generated. The system includes: (a) a first electromagnetic radiation source array that includes a plurality of first activatable radiation source elements that are positioned on a first movable carriage; (b) a second electromagnetic radiation source array that includes a plurality of second activatable radiation source elements that are positioned on a second movable carriage; (c) means for directing electromagnetic radiation from the first electromagnetic radiation source array and electromagnetic radiation from the second electromagnetic radiation source array toward a common optical path; (d) means for synchronizing (i) the movements of the first movable carriage and of the second movable carriage and (ii) the activation of the first electromagnetic radiation source array and of the second electromagnetic radiation source array to provide an essentially continuous illumination of electromagnetic radiation along the common optical path.

Indirect detection of radiation sources through direct detection of radiolysis products

DOEpatents

Farmer, Joseph C [Tracy, CA; Fischer, Larry E [Los Gatos, CA; Felter, Thomas E [Livermore, CA

2010-04-20

A system for indirectly detecting a radiation source by directly detecting radiolytic products. The radiation source emits radiation and the radiation produces the radiolytic products. A fluid is positioned to receive the radiation from the radiation source. When the fluid is irradiated, radiolytic products are produced. By directly detecting the radiolytic products, the radiation source is detected.

Active control of turbulent boundary layer-induced sound transmission through the cavity-backed double panels

NASA Astrophysics Data System (ADS)

Caiazzo, A.; Alujević, N.; Pluymers, B.; Desmet, W.

2018-05-01

This paper presents a theoretical study of active control of turbulent boundary layer (TBL) induced sound transmission through the cavity-backed double panels. The aerodynamic model used is based on the Corcos wall pressure distribution. The structural-acoustic model encompasses a source panel (skin panel), coupled through an acoustic cavity to the radiating panel (trim panel). The radiating panel is backed by a larger acoustic enclosure (the back cavity). A feedback control unit is located inside the acoustic cavity between the two panels. It consists of a control force actuator and a sensor mounted at the actuator footprint on the radiating panel. The control actuator can react off the source panel. It is driven by an amplified velocity signal measured by the sensor. A fully coupled analytical structural-acoustic model is developed to study the effects of the active control on the sound transmission into the back cavity. The stability and performance of the active control system are firstly studied on a reduced order model. In the reduced order model only two fundamental modes of the fully coupled system are assumed. Secondly, a full order model is considered with a number of modes large enough to yield accurate simulation results up to 1000 Hz. It is shown that convincing reductions of the TBL-induced vibrations of the radiating panel and the sound pressure inside the back cavity can be expected. The reductions are more pronounced for a certain class of systems, which is characterised by the fundamental natural frequency of the skin panel larger than the fundamental natural frequency of the trim panel.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cabrera-Palmer, Belkis

Predicting the performance of radiation detection systems at field sites based on measured performance acquired under controlled conditions at test locations, e.g., the Nevada National Security Site (NNSS), remains an unsolved and standing issue within DNDO’s testing methodology. Detector performance can be defined in terms of the system’s ability to detect and/or identify a given source or set of sources, and depends on the signal generated by the detector for the given measurement configuration (i.e., source strength, distance, time, surrounding materials, etc.) and on the quality of the detection algorithm. Detector performance is usually evaluated in the performance and operationalmore » testing phases, where the measurement configurations are selected to represent radiation source and background configurations of interest to security applications.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stavrov, Andrei; Yamamoto, Eugene

Radiation Portal Monitors (RPM) with plastic detectors represent the main instruments used for primary border (customs) radiation control. RPM are widely used because they are simple, reliable, relatively inexpensive and have a high sensitivity. However, experience using the RPM in various countries has revealed the systems have some grave shortcomings. There is a dramatic decrease of the probability of detection of radioactive sources under high suppression of the natural gamma background (radiation control of heavy cargoes, containers and, especially, trains). NORM (Naturally Occurring Radioactive Material) existing in objects under control trigger the so-called 'nuisance alarms', requiring a secondary inspection formore » source verification. At a number of sites, the rate of such alarms is so high it significantly complicates the work of customs and border officers. This paper presents a brief description of new variant of algorithm ASIA-New (New Advanced Source Identification Algorithm), which was developed by the Rapiscan company. It also demonstrates results of different tests and the capability of a new system to overcome the shortcomings stated above. New electronics and ASIA-New enables RPM to detect radioactive sources under a high background suppression (tested at 15-30%) and to verify the detected NORM (KCl) and the artificial isotopes (Co- 57, Ba-133 and other). New variant of ASIA is based on physical principles, a phenomenological approach and analysis of some important parameter changes during the vehicle passage through the monitor control area. Thanks to this capability main advantage of new system is that this system can be easily installed into any RPM with plastic detectors. Taking into account that more than 4000 RPM has been installed worldwide their upgrading by ASIA-New may significantly increase probability of detection and verification of radioactive sources even masked by NORM. This algorithm was tested for 1,395 passages of different transports (cars, trucks and trailers) without radioactive sources. It also was tested for 4,015 passages of these transports with radioactive sources of different activity (Co-57, Ba-133, Cs-137, Co-60, Ra-226, Th-232) and these sources masked by NORM (K-40) as well. (authors)« less

Deep-level stereoscopic multiple traps of acoustic vortices

NASA Astrophysics Data System (ADS)

Li, Yuzhi; Guo, Gepu; Ma, Qingyu; Tu, Juan; Zhang, Dong

2017-04-01

Based on the radiation pattern of a planar piston transducer, the mechanisms underlying the generation of axially controllable deep-level stereoscopic multiple traps of acoustic vortices (AV) using sparse directional sources were proposed with explicit formulae. Numerical simulations for the axial and cross-sectional distributions of acoustic pressure and phase were conducted for various ka (product of the wave number and the radius of transducer) values at the frequency of 1 MHz. It was demonstrated that, for bigger ka, besides the main-AV (M-AV) generated by the main lobes of the sources, cone-shaped side-AV (S-AV) produced by the side lobes were closer to the source plane at a relatively lower pressure. Corresponding to the radiation angles of pressure nulls between the main lobe and the side lobes of the sources, vortex valleys with nearly pressure zero could be generated on the central axis to form multiple traps, based on Gor'kov potential theory. The number and locations of vortex valleys could be controlled accurately by the adjustment of ka. With the established eight-source AV generation system, the existence of the axially controllable multiple traps was verified by the measured M-AV and S-AVs as well as the corresponding vortex valleys. The favorable results provided the feasibility of deep-level stereoscopic control of AV and suggested potential application of multiple traps for particle manipulation in the area of biomedical engineering.

Motility and gravitactic orientation of the flagellate, Euglena gracilis, impaired by artificial and solar UV-B radiation.

PubMed

Hader, D P; Liu, S M

1990-09-01

The effects of ultraviolet radiation on the gravitactic orientation of the freshwater flagellate, Euglena gracilis, were determined by a real time image analysis system. Both artificial UV radiation and solar radiation in a temperature-controlled growth chamber were employed. Histograms of gravitaxis showed that the degree of orientation decreased with increasing exposure time; this can be quantified using the Rayleigh test and upper quadrant summation. The effects of artificial UV radiation on the orientation are considerably stronger than those of solar radiation, probably because the radiation source emits higher fluence rates below 300 nm than found in solar radiation. The effects of monochromatic ultraviolet radiation on motility have been determined, and an action spectrum has been calculated.

Survey of Industrial, Agricultural, and Medical Applications of Radiometric Gauging and Process Control

PubMed Central

Hubbell, J. H.

1990-01-01

Photon and particle radiations (gamma rays, x rays, brems-strahlung, electrons and other charged particles, and neutrons) from radioactive isotopes, x-ray tubes, and accelerators are now widely used in gauging, production control, and other monitoring and metrology devices where avoidance of mechanical contact is desirable. The general principles of radiation gauges, which rely on detection of radiation transmitted by the sample, or on detection of scattered or other secondary radiations produced in the sample, are discussed. Examples of such devices currently used or at least shown to be feasible in industrial, transportation, building, mining, agricultural, medical, and other metrology situations are presented, drawing from a total of 146 selected technical and review paper reference sources here cited. PMID:28179800

Strategies for Radiation Hardness Testing of Power Semiconductor Devices

NASA Technical Reports Server (NTRS)

Soltis, James V. (Technical Monitor); Patton, Martin O.; Harris, Richard D.; Rohal, Robert G.; Blue, Thomas E.; Kauffman, Andrew C.; Frasca, Albert J.

2005-01-01

Plans on the drawing board for future space missions call for much larger power systems than have been flown in the past. These systems would employ much higher voltages and currents to enable more powerful electric propulsion engines and other improvements on what will also be much larger spacecraft. Long term human outposts on the moon and planets would also require high voltage, high current and long life power sources. Only hundreds of watts are produced and controlled on a typical robotic exploration spacecraft today. Megawatt systems are required for tomorrow. Semiconductor devices used to control and convert electrical energy in large space power systems will be exposed to electromagnetic and particle radiation of many types, depending on the trajectory and duration of the mission and on the power source. It is necessary to understand the often very different effects of the radiations on the control and conversion systems. Power semiconductor test strategies that we have developed and employed will be presented, along with selected results. The early results that we have obtained in testing large power semiconductor devices give a good indication of the degradation in electrical performance that can be expected in response to a given dose. We are also able to highlight differences in radiation hardness that may be device or material specific.

LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Control of the angular distribution of the radiation emitted by phase-locked laser arrays

NASA Astrophysics Data System (ADS)

Kachurin, O. R.; Lebedev, F. V.; Napartovich, M. A.; Khlynov, M. E.

1991-03-01

A numerical investigation was made of the influence of the number and packing density of a linear array of periodically arranged coherent sources on the efficiency of redistributing the radiation power from the side lobes to the main lobe of the angular distribution of the emitted radiation by using a binary phase corrector mounted in the image-doubling plane. The results are given of experimental investigations of a new device for improving the radiation pattern of phase-locked laser arrays.

10 CFR 36.61 - Inspection and maintenance.

Code of Federal Regulations, 2010 CFR

2010-01-01

... for radioactive contamination in pool water required by § 36.59(b) using a radiation check source, if... emergency source return control required by § 36.31(c). (7) Leak-tightness of systems through which pool water circulates (visual inspection). (8) Operability of the heat and smoke detectors and extinguisher...

A proposed method for electronic feedback compensation of damping in ferromagnetic resonance

DOE PAGES

Zohar, S.; Sterbinsky, G. E.

2017-07-10

Here, we propose an experimental technique for extending feedback compensation of dissipative radiation used in nuclear magnetic resonance (NMR) to encompass ferromagnetic resonance (FMR). This method uses a balanced microwave power detector whose output is phase shifted π/2, amplified, and fed back to drive precession. Using classical control theory, we predict an electronically controllable narrowing of field swept FMR line-widths. This technique is predicted to compensate other sources of spin dissipation in addition to radiative loss.

A proposed method for electronic feedback compensation of damping in ferromagnetic resonance

NASA Astrophysics Data System (ADS)

Zohar, S.; Sterbinsky, G. E.

2017-12-01

We propose an experimental technique for extending feedback compensation of dissipative radiation used in nuclear magnetic resonance (NMR) to encompass ferromagnetic resonance (FMR). This method uses a balanced microwave power detector whose output is phase shifted π / 2 , amplified, and fed back to drive precession. Using classical control theory, we predict an electronically controllable narrowing of field swept FMR line-widths. This technique is predicted to compensate other sources of spin dissipation in addition to radiative loss.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stavrov, Andrei; Yamamoto, Eugene

Radiation Portal Monitors (RPM) with plastic detectors represent the main instruments used for primary border (customs) radiation control. RPM are widely used because they are simple, reliable, relatively inexpensive and have a high sensitivity. However, experience using the RPM in various countries has revealed the systems have some grave shortcomings. There is a dramatic decrease of the probability of detection of radioactive sources under high suppression of the natural gamma background (radiation control of heavy cargoes, containers and, especially, trains). NORM (Naturally Occurring Radioactive Material) existing in objects under control trigger the so-called 'nuisance alarms', requiring a secondary inspection formore » source verification. At a number of sites, the rate of such alarms is so high it significantly complicates the work of customs and border officers. This paper presents a brief description of new variant of algorithm ASIA-New (New Advanced Source Identification Algorithm), which was developed by the authors and based on some experimental test results. It also demonstrates results of different tests and the capability of a new system to overcome the shortcomings stated above. New electronics and ASIA-New enables RPM to detect radioactive sources under a high background suppression (tested at 15-30%) and to verify the detected NORM (KCl) and the artificial isotopes (Co-57, Ba-133 and other). New variant of ASIA is based on physical principles and does not require a lot of special tests to attain statistical data for its parameters. That is why this system can be easily installed into any RPM with plastic detectors. This algorithm was tested for 1,395 passages of different transports (cars, trucks and trailers) without radioactive sources. It also was tested for 4,015 passages of these transports with radioactive sources of different activity (Co-57, Ba-133, Cs-137, Co-60, Ra-226, Th-232) and these sources masked by NORM (K-40) as well. (authors)« less

Design of a heat pipe governed thermal control system for the Solar Electric Propulsion Stage /SEPS/

NASA Technical Reports Server (NTRS)

Ruttner, L. E.; Wright, J. P.

1975-01-01

A 2200-w capacity spacecraft heat rejection system designed for the SEPS and utilizing heat pipe radiator panels has been investigated. The total thermal control system consists of two radiator panels connected to the heat source by variable conductance heat pipes (VCHP's). The system was designed to operate in the 223 to 333 temperature range. The radiators have an emittance of 0.88 at their operational temperature and a fin efficiency of approximately 80 percent. The radiators are thermally isolated from the SEPS and environment by multilayer insulation and thermal shields. Butane was selected as the working fluid for the VCHP because of its low freezing point (135), which is necessary to prevent diffusion freezeout of the liquid during the cold outbond missions. Helium was selected for the control gas. This paper describes the VCHP system, discusses the system design parameters and presents the results of the analyses.

Design of a radiation facility for very small specimens used in radiobiology studies

NASA Astrophysics Data System (ADS)

Rodriguez, Manuel; Jeraj, Robert

2008-06-01

A design of a radiation facility for very small specimens used in radiobiology is presented. This micro-irradiator has been primarily designed to irradiate partial bodies in zebrafish embryos 3-4 mm in length. A miniature x-ray, 50 kV photon beam, is used as a radiation source. The source is inserted in a cylindrical brass collimator that has a pinhole of 1.0 mm in diameter along the central axis to produce a pencil photon beam. The collimator with the source is attached underneath a computer-controlled movable table which holds the specimens. Using a 45° tilted mirror, a digital camera, connected to the computer, takes pictures of the specimen and the pinhole collimator. From the image provided by the camera, the relative distance from the specimen to the pinhole axis is calculated and coordinates are sent to the movable table to properly position the samples in the beam path. Due to its monitoring system, characteristic of the radiation beam, accuracy and precision of specimen positioning, and automatic image-based specimen recognition, this radiation facility is a suitable tool to irradiate partial bodies in zebrafish embryos, cell cultures or any other small specimen used in radiobiology research.

A Radiation Laboratory Curriculum Development at Western Kentucky University

NASA Astrophysics Data System (ADS)

Barzilov, Alexander P.; Novikov, Ivan S.; Womble, Phil C.

2009-03-01

We present the latest developments for the radiation laboratory curriculum at the Department of Physics and Astronomy of Western Kentucky University. During the last decade, the Applied Physics Institute (API) at WKU accumulated various equipment for radiation experimentation. This includes various neutron sources (computer controlled d-t and d-d neutron generators, and isotopic 252 Cf and PuBe sources), the set of gamma sources with various intensities, gamma detectors with various energy resolutions (NaI, BGO, GSO, LaBr and HPGe) and the 2.5-MeV Van de Graaff particle accelerator. XRF and XRD apparatuses are also available for students and members at the API. This equipment is currently used in numerous scientific and teaching activities. Members of the API also developed a set of laboratory activities for undergraduate students taking classes from the physics curriculum (Nuclear Physics, Atomic Physics, and Radiation Biophysics). Our goal is to develop a set of radiation laboratories, which will strengthen the curriculum of physics, chemistry, geology, biology, and environmental science at WKU. The teaching and research activities are integrated into real-world projects and hands-on activities to engage students. The proposed experiments and their relevance to the modern status of physical science are discussed.

Expression of NF-κB p50 in Tumor Stroma Limits the Control of Tumors by Radiation Therapy

PubMed Central

Crittenden, Marka R.; Cottam, Benjamin; Savage, Talicia; Nguyen, Cynthia; Newell, Pippa; Gough, Michael J.

2012-01-01

Radiation therapy aims to kill cancer cells with a minimum of normal tissue toxicity. Dying cancer cells have been proposed to be a source of tumor antigens and may release endogenous immune adjuvants into the tumor environment. For these reasons, radiation therapy may be an effective modality to initiate new anti-tumor adaptive immune responses that can target residual disease and distant metastases. However, tumors engender an environment dominated by M2 differentiated tumor macrophages that support tumor invasion, metastases and escape from immune control. In this study, we demonstrate that following radiation therapy of tumors in mice, there is an influx of tumor macrophages that ultimately polarize towards immune suppression. We demonstrate using in vitro models that this polarization is mediated by transcriptional regulation by NFκB p50, and that in mice lacking NFκB p50, radiation therapy is more effective. We propose that despite the opportunity for increased antigen-specific adaptive immune responses, the intrinsic processes of repair following radiation therapy may limit the ability to control residual disease. PMID:22761754

Active Control of Sound Radiation due to Subsonic Wave Scattering from Discontinuities on Thin Elastic Beams.

NASA Astrophysics Data System (ADS)

Guigou, Catherine Renee J.

1992-01-01

Much progress has been made in recent years in active control of sound radiation from vibrating structures. Reduction of the far-field acoustic radiation can be obtained by directly modifying the response of the structure by applying structural inputs rather than by adding acoustic sources. Discontinuities, which are present in many structures are often important in terms of sound radiation due to wave scattering behavior at their location. In this thesis, an edge or boundary type discontinuity (clamped edge) and a point discontinuity (blocking mass) are analytically studied in terms of sound radiation. When subsonic vibrational waves impinge on these discontinuities, large scattered sound levels are radiated. Active control is then achieved by applying either control forces, which approximate shakers, or pairs of control moments, which approximate piezoelectric actuators, near the discontinuity. Active control of sound radiation from a simply-supported beam is also examined. For a single frequency, the flexural response of the beam subject to an incident wave or an input force (disturbance) and to control forces or control moments is expressed in terms of waves of both propagating and near-field types. The far-field radiated pressure is then evaluated in terms of the structural response, using Rayleigh's formula or a stationary phase approach, depending upon the application. The control force and control moment magnitudes are determined by optimizing a quadratic cost function, which is directly related to the control performance. On determining the optimal control complex amplitudes, these can be resubstituted in the constitutive equations for the system under study and the minimized radiated fields can be evaluated. High attenuation in radiated sound power and radiated acoustic pressure is found to be possible when one or two active control actuators are located near the discontinuity, as is shown to be mostly associated with local changes in beam response near the discontinuity. The effect of the control actuators on the far-field radiated pressure, the wavenumber spectrum, the flexural displacement and the near-field time averaged intensity and pressure distributions are studied in order to further understand the control mechanisms. The influence of the near-field structural waves is investigated as well. Some experimental results are presented for comparison.

Solution of multi-element LED light sources development automation problem

NASA Astrophysics Data System (ADS)

Chertov, Aleksandr N.; Gorbunova, Elena V.; Korotaev, Valery V.; Peretyagin, Vladimir S.

2014-09-01

The intensive development of LED technologies resulted in the creation of multicomponent light sources in the form of controlled illumination devices based on usage of mentioned LED technologies. These light sources are used in different areas of production (for example, in the food industry for sorting products or in the textile industry for quality control, etc.). The use of LED lighting products in the devices used in specialized lighting, became possible due to wide range of colors of light, LED structures (which determines the direction of radiation, the spatial distribution and intensity of the radiation, electrical, heat, power and other characteristics), and of course, the possibility of obtaining any shade in a wide dynamic range of brightness values. LED-based lighting devices are notable for the diversity of parameters and characteristics, such as color radiation, location and number of emitters, etc. Although LED technologies have several advantages, however, they require more attention if you need to ensure a certain character of illumination distribution and/or distribution of the color picture at a predetermined distance (for example, at flat surface, work zone, area of analysis or observation). This paper presents software designed for the development of the multicomponent LED light sources. The possibility of obtaining the desired color and energy distribution at the zone of analysis by specifying the spatial parameters of the created multicomponent light source and using of real power, spectral and color parameters and characteristics of the LEDs is shown as well.

Debris- and radiation-induced damage effects on EUV nanolithography source collector mirror optics performance

NASA Astrophysics Data System (ADS)

Allain, J. P.; Nieto, M.; Hendricks, M.; Harilal, S. S.; Hassanein, A.

2007-05-01

Exposure of collector mirrors facing the hot, dense pinch plasma in plasma-based EUV light sources to debris (fast ions, neutrals, off-band radiation, droplets) remains one of the highest critical issues of source component lifetime and commercial feasibility of nanolithography at 13.5-nm. Typical radiators used at 13.5-nm include Xe and Sn. Fast particles emerging from the pinch region of the lamp are known to induce serious damage to nearby collector mirrors. Candidate collector configurations include either multi-layer mirrors (MLM) or single-layer mirrors (SLM) used at grazing incidence. Studies at Argonne have focused on understanding the underlying mechanisms that hinder collector mirror performance at 13.5-nm under fast Sn or Xe exposure. This is possible by a new state-of-the-art in-situ EUV reflectometry system that measures real time relative EUV reflectivity (15-degree incidence and 13.5-nm) variation during fast particle exposure. Intense EUV light and off-band radiation is also known to contribute to mirror damage. For example offband radiation can couple to the mirror and induce heating affecting the mirror's surface properties. In addition, intense EUV light can partially photo-ionize background gas (e.g., Ar or He) used for mitigation in the source device. This can lead to local weakly ionized plasma creating a sheath and accelerating charged gas particles to the mirror surface and inducing sputtering. In this paper we study several aspects of debris and radiation-induced damage to candidate EUVL source collector optics materials. The first study concerns the use of IMD simulations to study the effect of surface roughness on EUV reflectivity. The second studies the effect of fast particles on MLM reflectivity at 13.5-nm. And lastly the third studies the effect of multiple energetic sources with thermal Sn on 13.5-nm reflectivity. These studies focus on conditions that simulate the EUVL source environment in a controlled way.

Radiation in controlled environments: influence of lamp type and filter material

NASA Technical Reports Server (NTRS)

Bubenheim, D. L.; Bugbee, B.; Salisbury, F. B.

1988-01-01

Radiation in controlled environments was characterized using fluorescent and various high-intensity-discharge (HID) lamps, including metal halide, low-pressure sodium, and high-pressure sodium as the radiation source. The effects of water, glass, or Plexiglas filters on radiation were determined. Photosynthetic photon flux (PPF, 400 to 700 nm), spectra (400 to 1000 nm), shortwave radiation (285-2800 nm), and total radiation (300 to 100,000 nm) were measured, and photosynthetically active radiation (PAR, 400 to 700 nm) and longwave radiation (2800 to 100,000 nm) were calculated. Measurement of PPF alone was not an adequate characterization of the radiation environment. Total radiant flux varied among lamp types at equal PPF. HID lamps provided a lower percentage of longwave radiation than fluorescent lamps, but, when HID lamps provided PPF levels greater than that possible with fluorescent lamps, the amount of longwave radiation was high. Water was the most effective longwave radiation filter. Glass and Plexiglas similarly filtered longwave more than shortwave radiation, but transmission of nonphotosynthetic shortwave radiation was less with Plexiglas than glass. The filter materials tested would not be expected to influence photomorphogenesis because radiation in the action spectrum of phytochrome was not altered, but this may not be the only pigment involved.

Preliminary experiments on active control of fan noise from a turbofan engine

NASA Technical Reports Server (NTRS)

Thomas, R. H.; Burdisso, R. A.; Fuller, C. R.; O'Brien, W. F.

1993-01-01

In the preliminary experiments reported here, active acoustic sources positioned around the circumference of a turbofan engine were used to control the fan noise radiated forward through the inlet. The main objective was to demonstrate the potential of active techniques to alleviate the noise pollution that will be produced by the next generation of larger engines. A reduction of up to 19 dB in the radiation directivity was demonstrated in a zone that encompasses a 30-deg angle, near the error sensor, while spillover effects were observed toward the lateral direction. The simultaneous control of two tones was also demonstrated using two identical controllers in a parallel control configuration.

Chemical investigation of three plutonium–beryllium neutron sources

DOE PAGES

Byerly, Benjamin; Kuhn, Kevin; Colletti, Lisa; ...

2017-02-03

Thorough physical and chemical characterization of plutonium–beryllium (PuBe) neutron sources is an important capability with applications ranging from material accountancy to nuclear forensics. Furthermore, characterization of PuBe sources is not trivial owing to range of existing source designs and the need for adequate infrastructure to deal with radiation and protect the analyst. Our study demonstrates a method for characterization of three PuBe sources that includes physical inspection and imaging followed by controlled disassembly and destructive analysis.

Chemical investigation of three plutonium–beryllium neutron sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Byerly, Benjamin; Kuhn, Kevin; Colletti, Lisa

Thorough physical and chemical characterization of plutonium–beryllium (PuBe) neutron sources is an important capability with applications ranging from material accountancy to nuclear forensics. Furthermore, characterization of PuBe sources is not trivial owing to range of existing source designs and the need for adequate infrastructure to deal with radiation and protect the analyst. Our study demonstrates a method for characterization of three PuBe sources that includes physical inspection and imaging followed by controlled disassembly and destructive analysis.

Illumination control apparatus for compensating solar light

NASA Technical Reports Server (NTRS)

Owens, L. J. (Inventor)

1978-01-01

An illumination control apparatus is presented for supplementing light from solar radiation with light from an artificial light source to compensate for periods of insufficient levels of solar light. The apparatus maintains a desired illumination level within an interior space comprising an artificial light source connected to an electrical power source with a switch means for selectively energizing said light source. An actuator means for controlling the on-off operation of the switch means is connected to a light sensor which responses to the illumination level of the interior space. A limit switch carried adjacent to the actuator limits the movement of the actuator within a predetermined range so as to prevent further movement thereof during detection of erroneous illumination conditions.

An intelligent inspection and survey robot. Volume 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-12-15

Radioactive materials make up a significant part of the hazardous-material inventory of the Department of Energy. Much of the radioactive material will be inspected or handled by robotic systems that contain electronic circuits that may be damaged by gamma radiation and other particles emitted from radioactive material. This report examines several scenarios, the damage that may be inflicted, and methods that may be used to protect radiation-hardened robot control systems. Commercial sources of components and microcomputers that can withstand high radiation exposure are identified.

Widely tunable narrow-band coherent Terahertz radiation from an undulator at THU

NASA Astrophysics Data System (ADS)

Su, X.; Wang, D.; Tian, Q.; Liang, Y.; Niu, L.; Yan, L.; Du, Y.; Huang, W.; Tang, C.

2018-01-01

There is anxious demand for intense widely tunable narrow-band Terahertz (THz) radiation in scientific research, which is regarded as a powerful tool for the coherent control of matter. We report the generation of widely tunable THz radiation from a planar permanent magnet undulator at Tsinghua University (THU). A relativistic electron beam is compressed by a magnetic chicane into sub-ps bunch length to excite THz radiation in the undulator coherently. The THz frequency can be tuned from 0.4 THz to 10 THz continuously with narrow-band spectrums when the undulator gap ranges from 23 mm to 75 mm. The measured pulse THz radiation energy from 220 pC bunch is 3.5 μJ at 1 THz and tens of μJ pulse energy (corresponding peak power of 10 MW) can be obtained when excited by 1 nC beam extrapolated from the property of coherent radiation. The experimental results agree well with theoretical predictions, which demonstrates a suitable THz source for the many applications that require intense and widely tunable THz sources.

Enhancement of output power in a two-section periodical circular waveguide structure using magnetized plasma and a relativistic electron beam

NASA Astrophysics Data System (ADS)

Hasanbeigi, A.; Ashrafi, A.; Mehdian, H.

2018-02-01

In the present paper, the excitation of electromagnetic wave by relativistic electron beam, as a radiation source, in a two-section periodical plasma waveguide is investigated. The dispersion relation of TM wave is derived and then solved numerically. Next, the effect of plasma, as an extra controlling parameter, on this radiation source is investigated. Results show that the presence of magnetized plasma can lead to significant increase in output power and it can be an extra parameter for tuning the frequency by varying the plasma density.

Development of a directivity-controlled piezoelectric transducer for sound reproduction

NASA Astrophysics Data System (ADS)

Bédard, Magella; Berry, Alain

2008-04-01

Present sound reproduction systems do not attempt to simulate the spatial radiation of musical instruments, or sound sources in general, even though the spatial directivity has a strong impact on the psychoacoustic experience. A transducer consisting of 4 piezoelectric elemental sources made from curved PVDF films is used to generate a target directivity pattern in the horizontal plane, in the frequency range of 5-20 kHz. The vibratory and acoustical response of an elemental source is addressed, both theoretically and experimentally. Two approaches to synthesize the input signals to apply to each elemental source are developed in order to create a prescribed, frequency-dependent acoustic directivity. The circumferential Fourier decomposition of the target directivity provides a compromise between the magnitude and the phase reconstruction, whereas the minimization of a quadratic error criterion provides a best magnitude reconstruction. This transducer can improve sound reproduction by introducing the spatial radiation aspect of the original source at high frequency.

Signal conditioner circuit for photomultiplier tube

NASA Technical Reports Server (NTRS)

Cellier, A.; Hoover, W. M.

1970-01-01

Miniaturized circuit improves measurement of radiation dose absorbed in a scintillation crystal. The temperature coefficient of the field-effect transistor gate-source voltage in the isolation amplifier can be readily controlled.

Adaptors for radiation detectors

DOEpatents

Livesay, Ronald Jason

2014-04-22

Described herein are adaptors and other devices for radiation detectors that can be used to make accurate spectral measurements of both small and large bulk sources of radioactivity, such as building structures, soils, vessels, large equipment, and liquid bodies. Some exemplary devices comprise an adaptor for a radiation detector, wherein the adaptor can be configured to collimate radiation passing through the adapter from an external radiation source to the radiation detector and the adaptor can be configured to enclose a radiation source within the adapter to allow the radiation detector to measure radiation emitted from the enclosed radiation source.

Adaptors for radiation detectors

DOEpatents

Livesay, Ronald Jason

2015-07-28

Described herein are adaptors and other devices for radiation detectors that can be used to make accurate spectral measurements of both small and large bulk sources of radioactivity, such as building structures, soils, vessels, large equipment, and liquid bodies. Some exemplary devices comprise an adaptor for a radiation detector, wherein the adaptor can be configured to collimate radiation passing through the adapter from an external radiation source to the radiation detector and the adaptor can be configured to enclose a radiation source within the adapter to allow the radiation detector to measure radiation emitted from the enclosed radiation source.

Opportunity for Collaboration Between Radiation Injury Treatment Network Centers and Medical Toxicology Specialists.

PubMed

Davlantes, Elizabeth; Shartar, Samuel; Venero, Jennifer; Steck, Alaina; Langston, Amelia; Kazzi, Ziad N

2017-08-01

The Radiation Injury Treatment Network (RITN) comprises >50 centers across the United States that are poised to care for victims of a radiation emergency. The network is organized around bone marrow transplant centers because these facilities excel in both radiation medicine and the care of patients with severe bone marrow depression. A radiation emergency may cause not only irradiation from an external source but also internal contamination with radioactive material. Because medical toxicologists are trained in radiation injury management and have expertise in the management of internal contamination, RITN centers may benefit from partnerships with medical toxicology resources, which may be located at academic medical centers, hospital inpatient clinical services, outpatient clinics, or poison control centers. We determined the locations of existing RITN centers and assessed their proximity to various medical toxicology resources, including medical toxicology fellowship programs, inpatient toxicology services, outpatient toxicology clinics, and poison control centers. Data were derived from publicly available Internet sources in March 2015. The majority of RITN centers do not have a medical toxicology fellowship, an inpatient toxicology service, or an outpatient toxicology clinic within the same institution. Fifty-seven percent of RITN centers have at least one of these resources located in the same city, however, and 73% of centers have at least one of these resources or a poison control center within the same city. Ninety-five percent of RITN centers have at least one medical toxicology resource within the state. Most RITN centers are located in the same city as at least one medical toxicology resource. Establishing relationships between RITN centers and medical toxicologists needs to be explored further.

76 FR 6692 - Radiation Sources on Army Land

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-08

...-AA58 Radiation Sources on Army Land AGENCY: Department of the Army, DoD. ACTION: Final rule. SUMMARY: The Department of the Army is finalizing revisions to its regulation concerning radiation sources on... Radiation Permit (ARP) from the garrison commander to use, store, or possess ionizing radiation sources on...

Closed Brayton Cycle Power Conversion Unit for Fission Surface Power Phase I Final Report

NASA Technical Reports Server (NTRS)

Fuller, Robert L.

2010-01-01

A Closed Brayton cycle power conversion system has been developed to support the NASA fission surface power program. The goal is to provide electricity from a small nuclear reactor heat source for surface power production for lunar and Mars environments. The selected media for a heat source is NaK 78 with water as a cooling source. The closed Brayton cycle power was selected to be 12 kWe output from the generator terminals. A heat source NaK temperature of 850 K plus or minus 25 K was selected. The cold source water was selected at 375 K plus or minus 25 K. A vacuum radiation environment of 200 K is specified for environmental operation. The major components of the system are the power converter, the power controller, and the top level data acquisition and control unit. The power converter with associated sensors resides in the vacuum radiation environment. The power controller and data acquisition system reside in an ambient laboratory environment. Signals and power are supplied across the pressure boundary electrically with hermetic connectors installed on the vacuum vessel. System level analyses were performed on working fluids, cycle design parameters, heater and cooling temperatures, and heat exchanger options that best meet the needs of the power converter specification. The goal is to provide a cost effective system that has high thermal-to-electric efficiency in a compact, lightweight package.

Nuclear Physics Meets the Sources of the Ultra-High Energy Cosmic Rays.

PubMed

Boncioli, Denise; Fedynitch, Anatoli; Winter, Walter

2017-07-07

The determination of the injection composition of cosmic ray nuclei within astrophysical sources requires sufficiently accurate descriptions of the source physics and the propagation - apart from controlling astrophysical uncertainties. We therefore study the implications of nuclear data and models for cosmic ray astrophysics, which involves the photo-disintegration of nuclei up to iron in astrophysical environments. We demonstrate that the impact of nuclear model uncertainties is potentially larger in environments with non-thermal radiation fields than in the cosmic microwave background. We also study the impact of nuclear models on the nuclear cascade in a gamma-ray burst radiation field, simulated at a level of complexity comparable to the most precise cosmic ray propagation code. We conclude with an isotope chart describing which information is in principle necessary to describe nuclear interactions in cosmic ray sources and propagation.

Ground-motion signature of dynamic ruptures on rough faults

NASA Astrophysics Data System (ADS)

Mai, P. Martin; Galis, Martin; Thingbaijam, Kiran K. S.; Vyas, Jagdish C.

2016-04-01

Natural earthquakes occur on faults characterized by large-scale segmentation and small-scale roughness. This multi-scale geometrical complexity controls the dynamic rupture process, and hence strongly affects the radiated seismic waves and near-field shaking. For a fault system with given segmentation, the question arises what are the conditions for producing large-magnitude multi-segment ruptures, as opposed to smaller single-segment events. Similarly, for variable degrees of roughness, ruptures may be arrested prematurely or may break the entire fault. In addition, fault roughness induces rupture incoherence that determines the level of high-frequency radiation. Using HPC-enabled dynamic-rupture simulations, we generate physically self-consistent rough-fault earthquake scenarios (M~6.8) and their associated near-source seismic radiation. Because these computations are too expensive to be conducted routinely for simulation-based seismic hazard assessment, we thrive to develop an effective pseudo-dynamic source characterization that produces (almost) the same ground-motion characteristics. Therefore, we examine how variable degrees of fault roughness affect rupture properties and the seismic wavefield, and develop a planar-fault kinematic source representation that emulates the observed dynamic behaviour. We propose an effective workflow for improved pseudo-dynamic source modelling that incorporates rough-fault effects and its associated high-frequency radiation in broadband ground-motion computation for simulation-based seismic hazard assessment.

Examination system utilizing ionizing radiation and a flexible, miniature radiation detector probe

DOEpatents

Majewski, S.; Kross, B.J.; Zorn, C.J.; Majewski, L.A.

1996-10-22

An optimized examination system and method based on the Reverse Geometry X-Ray{trademark} (RGX{trademark}) radiography technique are presented. The examination system comprises a radiation source, at least one flexible, miniature radiation detector probe positioned in appropriate proximity to the object to be examined and to the radiation source with the object located between the source and the probe, a photodetector device attachable to an end of the miniature radiation probe, and a control unit integrated with a display device connected to the photodetector device. The miniature radiation detector probe comprises a scintillation element, a flexible light guide having a first end optically coupled to the scintillation element and having a second end attachable to the photodetector device, and an opaque, environmentally-resistant sheath surrounding the flexible light guide. The probe may be portable and insertable, or may be fixed in place within the object to be examined. An enclosed, flexible, liquid light guide is also presented, which comprises a thin-walled flexible tube, a liquid, preferably mineral oil, contained within the tube, a scintillation element located at a first end of the tube, closures located at both ends of the tube, and an opaque, environmentally-resistant sheath surrounding the flexible tube. The examination system and method have applications in non-destructive material testing for voids, cracks, and corrosion, and may be used in areas containing hazardous materials. In addition, the system and method have applications for medical and dental imaging. 5 figs.

Examination system utilizing ionizing radiation and a flexible, miniature radiation detector probe

DOEpatents

Majewski, Stanislaw; Kross, Brian J.; Zorn, Carl J.; Majewski, Lukasz A.

1996-01-01

An optimized examination system and method based on the Reverse Geometry X-Ray.RTM. (RGX.RTM.) radiography technique are presented. The examination system comprises a radiation source, at least one flexible, miniature radiation detector probe positioned in appropriate proximity to the object to be examined and to the radiation source with the object located between the source and the probe, a photodetector device attachable to an end of the miniature radiation probe, and a control unit integrated with a display device connected to the photodetector device. The miniature radiation detector probe comprises a scintillation element, a flexible light guide having a first end optically coupled to the scintillation element and having a second end attachable to the photodetector device, and an opaque, environmentally-resistant sheath surrounding the flexible light guide. The probe may be portable and insertable, or may be fixed in place within the object to be examined. An enclosed, flexible, liquid light guide is also presented, which comprises a thin-walled flexible tube, a liquid, preferably mineral oil, contained within the tube, a scintillation element located at a first end of the tube, closures located at both ends of the tube, and an opaque, environmentally-resistant sheath surrounding the flexible tube. The examination system and method have applications in non-destructive material testing for voids, cracks, and corrosion, and may be used in areas containing hazardous materials. In addition, the system and method have applications for medical and dental imaging.

Light emitting diodes as a plant lighting source

NASA Technical Reports Server (NTRS)

Bula, R. J.; Tennessen, D. J.; Morrow, R. C.; Tibbitts, T. W.

1994-01-01

Electroluminescence in solid materials is defined as the generation of light by the passage of an electric current through a body of solid material under an applied electric field. A specific type of electroluminescence, first noted in 1923, involves the generation of photons when electrons are passed through a p-n junction of certain solid materials (junction of a n-type semiconductor, an electron donor, and a p-type semiconductor, an electron acceptor). The development of this light emitting semiconductor technology dates back less than 30 years. During this period of time, the LED has evolved from a rare and expensive light generating device to one of the most widely used electronic components. A number of LED characteristics are of considerable importance in selecting a light source for plant lighting in a controlled environment facility. Of particular importance is the characteristic that light is generated by an LED at a rate far greater than the corresponding thermal radiation predicted by the bulk temperature of the device as defined by Plank's radiation law. This is in sharp contrast to other light sources, such as an incandescent or high intensity discharge lamp. A plant lighting system for controlled environments must provide plants with an adequate flux of photosynthetically active radiation, plus providing photons in the spectral regions that are involved in the photomorphogenic and phototropic responses that result in normal plant growth and development. Use of light sources that emit photons over a broad spectral range generally meet these two lighting requirements. Since the LED's emit over specific spectral regions, they must be carefully selected so that the levels of photsynthetically active and photomorphogenic and phototropic radiation meet these plant requirements.

Radiation response of industrial materials: Dose-rate and morphology implications

NASA Astrophysics Data System (ADS)

Berejka, Anthony J.

2007-08-01

Industrial uses of ionizing radiation mostly rely upon high current, high dose-rate (100 kGy/s) electron beam (EB) accelerators. To a lesser extent, industry uses low dose-rate (2.8 × 10-3 kGy/s) radioactive Cobalt-60 as a gamma source, generally for some rather specific purposes, as medical device sterilization and the treatment of food and foodstuffs. There are nearly nine times as many (∼1400) high current EB units in commercial operation than gamma sources (∼160). However, gamma sources can be easily scaled-down so that much research on materials effects is conducted using gamma radiation. Likewise, laboratories are more likely to have very low beam current and consequently low dose-rate accelerators such as Van de Graaff generators and linear accelerators. With the advent of very high current EB accelerators, X-ray processing has become an industrially viable option. With X-rays from high power sources, dose-rates can be modulated based upon accelerator power and the attenuation of the X-ray by the distance of the material from the X-ray target. Dose and dose-rate dependence has been found to be of consequence in several commercial applications which can employ the use of ionizing radiation. The combination of dose and dose-rate dependence of the polymerization and crosslinking of wood impregnants and of fiber composite matrix materials can yield more economically viable results which have promising commercial potential. Monomer and oligomer structure also play an important role in attaining these desirable results. The influence of morphology is shown on the radiation response of olefin polymers, such as ethylene, propylene and isobutylene polymers and their copolymers. Both controlled morphology and controlled dose-rate have commercial consequences. These are also impacted both by the adroit selection of materials and through the possible use of X-ray processing.

The space experiment CERASP: Definition of a space-suited radiation source and growth conditions for human cells

NASA Astrophysics Data System (ADS)

Hellweg, Christine E.; Baumstark-Khan, Christa; Spitta, Luis; Thelen, Melanie; Arenz, Andrea; Franz, Markus; Schulze-Varnholt, Dirk; Berger, Thomas; Reitz, Günther

The combined action of ionizing radiation and microgravity will continue to influence future space missions, with special risks for astronauts on the Moon surface or for long duration missions to Mars. It has been estimated that on a 3-year mission to Mars about 3% of the bodies' cell nuclei would have been hit by one iron ion with the consequence that nuclear DNA will be heavily damaged. There is increasing evidence that basic cellular functions are sensitive not only to radiation but also to microgravity. DNA repair studies in space on bacteria, yeast cells and human fibroblasts, which were irradiated before, flight, gave contradictory results: from inhibition of repair by microgravity to enhancement, whereas others did not detect any influence of microgravity on repair. The space experiment CERASP (CEllular Responses to RAdiation in SPace) to be performed at the International Space Station (ISS) is aimed to supply basic information on the cellular response in microgravity to radiation applied during flight. It makes use of a recombinant human cell line as reporter for cellular signal transduction modulation by genotoxic environmental conditions. The main biological endpoints under investigation will be gene activation based on enhanced green fluorescent protein (EGFP, originally isolated from the bioluminescent jellyfish Aequorea victoria) expression controlled by a DNA damage-dependent promoter element which reflects the activity of the nuclear factor kappa B (NF- κB) pathway. The NF- κB family of proteins plays a major role in the inflammatory and immune response, cell proliferation and differentiation, anti-apoptosis and tumorgenesis. For radiation exposure during space flight a radiation source has been constructed as damage accumulation by cosmic radiation will certainly be insufficient for analysis. The space experiment specific hardware consists of a specially designed radiation source made up of the β-emitter promethium-147, combined with a miniaturized culture vessel and a seeding apparatus. With this prototype hardware, the requirements of CERASP can be fulfilled with cells growing on the polytetrafluoroethylene foil. The radiation source can be enveloped with additional titanium foils for safety issues. The results from the preparatory experimental phase clearly show that the Pm-147 radiation source meets the requirements for the space experiment CERASP.

Source Physics Experiment: Research in Support of Verification and Nonproliferation

DTIC Science & Technology

2011-09-01

designed to provide a carefully controlled seismic and strong motion data set from buried explosions at the Nevada National Security Site (NNSS). The...deposition partitioned into internal (heat and plastic strain) and kinetic (e.g., radiated seismic ) energy, giving more confidence in predicted free...ample information to study dry and water-saturated fractures, local lithology and topography on the radiated seismic wavefield. Spallation on

Control of the Earth's electric field intensity through solar wind modulation of galactic cosmic radiation: Support for a proposed atmospheric electrical sun-weather mechanism

NASA Technical Reports Server (NTRS)

Markson, R.

1980-01-01

The ionospheric potential and galactic cosmic radiation, found to be inversely correlated with the solar wind velocity are examined as being germane to weather modification. Since the ionospheric potential is proportional to the fair weather electric field intensity and cosmic radiation is the dominant source of atmospheric ionization, it is concluded that the Earth's overall electric field varies in phase with atmospheric ionization and that the latter is modulated by the solar wind. A proposed mechanism, in which solar control of ionizing radiation influences atmospheric electrification and thus possibly cloud physical processes is discussed. An experimental approach to critically test the proposed mechanism through comparison of the temporal variation of the Earth's electric field with conditions in the interplanetary medium is outlined.

Development of the integrated control system for the microwave ion source of the PEFP 100-MeV proton accelerator

NASA Astrophysics Data System (ADS)

Song, Young-Gi; Seol, Kyung-Tae; Jang, Ji-Ho; Kwon, Hyeok-Jung; Cho, Yong-Sub

2012-07-01

The Proton Engineering Frontier Project (PEFP) 20-MeV proton linear accelerator is currently operating at the Korea Atomic Energy Research Institute (KAERI). The ion source of the 100-MeV proton linac needs at least a 100-hour operation time. To meet the goal, we have developed a microwave ion source that uses no filament. For the ion source, a remote control system has been developed by using experimental physics and the industrial control system (EPICS) software framework. The control system consists of a versa module europa (VME) and EPICS-based embedded applications running on a VxWorks real-time operating system. The main purpose of the control system is to control and monitor the operational variables of the components remotely and to protect operators from radiation exposure and the components from critical problems during beam extraction. We successfully performed the operation test of the control system to confirm the degree of safety during the hardware performance.

Simulating X-ray bursts with a radiation hydrodynamics code

NASA Astrophysics Data System (ADS)

Seong, Gwangeon; Kwak, Kyujin

2018-04-01

Previous simulations of X-ray bursts (XRBs), for example, those performed by MESA (Modules for Experiments in Stellar Astrophysics) could not address the dynamical effects of strong radiation, which are important to explain the photospheric radius expansion (PRE) phenomena seen in many XRBs. In order to study the effects of strong radiation, we propose to use SNEC (the SuperNova Explosion Code), a 1D Lagrangian open source code that is designed to solve hydrodynamics and equilibrium-diffusion radiation transport together. Because SNEC is able to control modules of radiation-hydrodynamics for properly mapped inputs, radiation-dominant pressure occurring in PRE XRBs can be handled. Here we present simulation models for PRE XRBs by applying SNEC together with MESA.

Samarium-145 and its use as a radiation source

DOEpatents

Fairchild, Ralph G.; Laster, Brenda H.; Packer, Samuel

1989-09-05

The present invention covers a new radiation source, samarium-145, with radiation energies slightly above those of I-125 and a half-life of 340 days. The samarium-145 source is produced by neutron irradiation of SM-144. This new source is useful as the implanted radiation source in photon activation therapy of malignant tumors to activate the stable I-127 contained in the IdUrd accumulated in the tumor, causing radiation sensitization and Auger cascades that irreperably damage the tumor cells. This new source is also useful as a brachytherapy source.

Samarium-145 and its use as a radiation source

DOEpatents

Fairchild, Ralph G.; Laster, Brenda H.; Packer, Samuel

1989-01-01

The present invention covers a new radiation source, samarium-145, with radiation energies slightly above those of I-125 and a half-life of 340 days. The samarium-145 source is produced by neutron irradiation of SM-144. This new source is useful as the implanted radiation source in photon activation therapy of malignant tumors to activate the stable I-127 contained in the IdUrd accumulated in the tumor, causing radiation sensitization and Auger cascades that irreperably damage the tumor cells. This new source is also useful as a brachytherapy source.

Control system of mobile radiographic complex to study equations of state of substances

NASA Astrophysics Data System (ADS)

Belov, O. V.; Valekzhanin, R. V.; Kustov, D. V.; Shamro, O. A.; Sharov, T. V.

2017-05-01

A source of x-ray radiation is one of the tools to study equations of state of substances in dynamics. The mobile radiographic bench based on BIM-1500 [1] was developed in RFNC-VNIIEF to increase output parameters of the x-ray radiation source. From automated control system side, BIM-1500 is a set of six high-voltage generators based on the capacitive energy storage, technological equipment, and elements of a blocking system. This paper considers automated control system of the mobile radiographic bench MCA BIM 1500. It consists of six high-voltage generator control circuits, synchronization subsystem, and block subsystem. The object of control has some peculiarities: high level of electromagnetic noise, remoteness of the control panel from the object of control. In connection with this, the coupling devices are arranged closer to the object of control and performed in the form of a set of galvanically insulated control units, which are combined into a net. The operator runs MCA BIM using the operator’s screens on PC or by means of manual control on the equipment in the mode of debugging. The control software provides performance of the experiment in automatic regime in accordance with preset settings. The operator can stop the experiment at the stage of charging the capacitive storage.

Controlling radiation fields in siemans designed light water reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riess, R.; Marchl, T.

1995-03-01

An essential item for the control of radiation fields is the minimization of the use of satellites in the reactor systems of Light Water Reactors (LWRs). A short description of the qualification of Co-replacement materials will be followed by an illustration of the locations where these materials were implemented in Siemens designed LWRs. Especially experiences in PWRs show the immense influence of reduction of cobalt sources on dose rate buildup. The corrosion and the fatique and wear behavior of the replacement materials has not created concern up to now. A second tool to keep occupational radiation doses at a lowmore » level in PWRs is the use of the modified B/Li-chemistry. This is practized in Siemens designed plants by keeping the Li level at a max. value of 2 ppm until it reaches a pH (at 300{degrees}C) of {approximately}7.4. This pH is kept constant until the end of the cycle. The substitution of cobalt base alloys and thus the removal of the Co-59 sources from the system had the largest impact on the radiation levels. Nonetheless, the effectiveness of the coolant chemistry should not be neglected either. Several years of successful operation of PWRs with the replacement materials resulted in an occupational radiation exposure which is below 0.5 man-Sievert/plant and year.« less

21 CFR 892.5700 - Remote controlled radionuclide applicator system.

Code of Federal Regulations, 2011 CFR

2011-04-01

... source into the body or to the surface of the body for radiation therapy. This generic type of device may include patient and equipment supports, component parts, treatment planning computer programs, and...

Active Vibration Control for Helicopter Interior Noise Reduction Using Power Minimization

NASA Technical Reports Server (NTRS)

Mendoza, J.; Chevva, K.; Sun, F.; Blanc, A.; Kim, S. B.

2014-01-01

This report describes work performed by United Technologies Research Center (UTRC) for NASA Langley Research Center (LaRC) under Contract NNL11AA06C. The objective of this program is to develop technology to reduce helicopter interior noise resulting from multiple gear meshing frequencies. A novel active vibration control approach called Minimum Actuation Power (MAP) is developed. MAP is an optimal control strategy that minimizes the total input power into a structure by monitoring and varying the input power of controlling sources. MAP control was implemented without explicit knowledge of the phasing and magnitude of the excitation sources by driving the real part of the input power from the controlling sources to zero. It is shown that this occurs when the total mechanical input power from the excitation and controlling sources is a minimum. MAP theory is developed for multiple excitation sources with arbitrary relative phasing for single or multiple discrete frequencies and controlled by a single or multiple controlling sources. Simulations and experimental results demonstrate the feasibility of MAP for structural vibration reduction of a realistic rotorcraft interior structure. MAP control resulted in significant average global vibration reduction of a single frequency and multiple frequency excitations with one controlling actuator. Simulations also demonstrate the potential effectiveness of the observed vibration reductions on interior radiated noise.

A theoretical study on directivity control of multiple-loudspeaker system with a quadrupole radiation pattern in low frequency range

NASA Astrophysics Data System (ADS)

Irwansyah, Kuse, Naoyuki; Usagawa, Tsuyoshi

2017-08-01

Directivity pattern of an ordinary loudspeaker becomes more directive at higher frequencies. However, because a single loudspeaker tends to radiate uniformly in all directions at low frequencies, reverberation from surrounding building walls may affect speech intelligibility when installing a multiple-loudspeaker system at crossroads. As an alternative, a sharply directive sound source is recommended to be used, but in many cases the directivity of an ordinary loudspeaker is less sharp at lower frequencies. Therefore, in order to overcome such a limitation, this paper discusses the possibility of using four loudspeakers under active control to realize a quadrupole radiation pattern in low frequency range. In this study, the radiation pattern of a primary loudspeaker and three secondary loudspeakers has been modelled. By placing the loudspeakers close together in the direction of 0°, 90°, 180°, and 270°, it was theoretically demonstrated that a quadrupole radiation pattern can be shaped in the target frequency range up to 600 Hz by simply controlling the directivity in three of four directions which are 45°, 135°, 225°, and 315°. Although, the radiation pattern model is far from realistic configurations and conditions, it is possible to realize a quadrupole radiation pattern in the low frequency range.

Multiple layer optical memory system using second-harmonic-generation readout

DOEpatents

Boyd, Gary T.; Shen, Yuen-Ron

1989-01-01

A novel optical read and write information storage system is described which comprises a radiation source such as a laser for writing and illumination, the radiation source being capable of radiating a preselected first frequency; a storage medium including at least one layer of material for receiving radiation from the radiation source and capable of being surface modified in response to said radiation source when operated in a writing mode and capable of generating a pattern of radiation of the second harmonic of the preselected frequency when illuminated by the radiation source at the preselected frequency corresponding to the surface modifications on the storage medium; and a detector to receive the pattern of second harmonic frequency generated.

Potential radiation control of biofouling bacteria on intake filters

NASA Astrophysics Data System (ADS)

Eichholz, Geoffrey G.; Jones, Cynthia G.; Haynes, Harold E.

The biofouling of filters at deep wells supplying water for industrial and drinking water purposes by various iron- and sulfur-reducing bacteria is a wide-spread problem in the United States and can cause serious economic losses. Among the means of control, steam heating or chemical additives can be applied only intermittently and have their own environmental impact. Preliminary studies have shown that installation of a sealed gamma radiation source may provide an alternative solution. Analysis of a range of water samples from contaminated wells identified many of the samples as rich in barsiderocapsa and barpseudomona bacteria. Static and dynamic experiments on water samples at various does and dose rates have shown that these organisms are relatively radiation-sensitive, with a lethal dose in the range of 200-400Gy (20-40kR). Since the main objective is to restrict growth or deposit of plaque on filters, dose rates of the order of 50-75 Gy/hr would be adequate. Such dose rates could be obtained with relatively weak sources, depending on filter dimensions. A conceptual design for such systems has been proposed.

Sirepo for Synchrotron Radiation Workshop

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nagler, Robert; Moeller, Paul; Rakitin, Maksim

Sirepo is an open source framework for cloud computing. The graphical user interface (GUI) for Sirepo, also known as the client, executes in any HTML5 compliant web browser on any computing platform, including tablets. The client is built in JavaScript, making use of the following open source libraries: Bootstrap, which is fundamental for cross-platform web applications; AngularJS, which provides a model–view–controller (MVC) architecture and GUI components; and D3.js, which provides interactive plots and data-driven transformations. The Sirepo server is built on the following Python technologies: Flask, which is a lightweight framework for web development; Jinja, which is a secure andmore » widely used templating language; and Werkzeug, a utility library that is compliant with the WSGI standard. We use Nginx as the HTTP server and proxy, which provides a scalable event-driven architecture. The physics codes supported by Sirepo execute inside a Docker container. One of the codes supported by Sirepo is the Synchrotron Radiation Workshop (SRW). SRW computes synchrotron radiation from relativistic electrons in arbitrary magnetic fields and propagates the radiation wavefronts through optical beamlines. SRW is open source and is primarily supported by Dr. Oleg Chubar of NSLS-II at Brookhaven National Laboratory.« less

An engineering approach to controlling indoor air quality.

PubMed

Woods, J E

1991-11-01

Evidence is accumulating that indicates air quality problems in residential and commercial buildings are nearly always associated with inadequacies in building design and methods of operation. Thus, the very systems depended on to control the indoor environment can become indirect sources of contamination if diligence is not exercised at each stage of a building's life: a) planning and design, b) construction and commissioning, c) operation, and d) demolition or renovation. In this paper, an engineering perspective is presented in which the existing building stock is characterized in terms of its environmental performance. Preliminary data indicate that 20 to 30% of the existing buildings have sufficient problems to manifest as sick-building syndrome or building-related illness, while another 10 to 20% may have undetected problems. Thus, only about 50 to 70% of the existing buildings qualify as healthy buildings. Two methods and three mechanisms of control are described to achieve "acceptable" indoor air quality: source control and exposure control. If sources cannot be removed, some level of occupant exposure will result. To control exposures with acceptable values, the primary sensory receptors of the occupants (i.e., thermal, ocular, auditory, and olfactory) cannot be excessively stimulated. The three exposure control mechanisms are conduction, radiation, and convection. To achieve acceptable occupant responses, it is often practical to integrate the mechanisms of radiation and convection in heating, ventilating, and air conditioning systems that are designed to provide acceptable thermal, acoustic, and air quality conditions within occupied spaces.(ABSTRACT TRUNCATED AT 250 WORDS)

An engineering approach to controlling indoor air quality.

PubMed Central

Woods, J E

1991-01-01

Evidence is accumulating that indicates air quality problems in residential and commercial buildings are nearly always associated with inadequacies in building design and methods of operation. Thus, the very systems depended on to control the indoor environment can become indirect sources of contamination if diligence is not exercised at each stage of a building's life: a) planning and design, b) construction and commissioning, c) operation, and d) demolition or renovation. In this paper, an engineering perspective is presented in which the existing building stock is characterized in terms of its environmental performance. Preliminary data indicate that 20 to 30% of the existing buildings have sufficient problems to manifest as sick-building syndrome or building-related illness, while another 10 to 20% may have undetected problems. Thus, only about 50 to 70% of the existing buildings qualify as healthy buildings. Two methods and three mechanisms of control are described to achieve "acceptable" indoor air quality: source control and exposure control. If sources cannot be removed, some level of occupant exposure will result. To control exposures with acceptable values, the primary sensory receptors of the occupants (i.e., thermal, ocular, auditory, and olfactory) cannot be excessively stimulated. The three exposure control mechanisms are conduction, radiation, and convection. To achieve acceptable occupant responses, it is often practical to integrate the mechanisms of radiation and convection in heating, ventilating, and air conditioning systems that are designed to provide acceptable thermal, acoustic, and air quality conditions within occupied spaces.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1821369

21 CFR 886.5100 - Ophthalmic beta radiation source.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ophthalmic beta radiation source. 886.5100 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5100 Ophthalmic beta radiation source. (a) Identification. An ophthalmic beta radiation source is a device intended to apply superficial...

21 CFR 886.5100 - Ophthalmic beta radiation source.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ophthalmic beta radiation source. 886.5100 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5100 Ophthalmic beta radiation source. (a) Identification. An ophthalmic beta radiation source is a device intended to apply superficial...

21 CFR 886.5100 - Ophthalmic beta radiation source.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ophthalmic beta radiation source. 886.5100 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5100 Ophthalmic beta radiation source. (a) Identification. An ophthalmic beta radiation source is a device intended to apply superficial...

21 CFR 886.5100 - Ophthalmic beta radiation source.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ophthalmic beta radiation source. 886.5100 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5100 Ophthalmic beta radiation source. (a) Identification. An ophthalmic beta radiation source is a device intended to apply superficial...

21 CFR 886.5100 - Ophthalmic beta radiation source.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic beta radiation source. 886.5100 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5100 Ophthalmic beta radiation source. (a) Identification. An ophthalmic beta radiation source is a device intended to apply superficial...

10 CFR 35.647 - Additional technical requirements for mobile remote afterloader units.

Code of Federal Regulations, 2010 CFR

2010-01-01

... on the remote afterloader unit, on the control console, and in the facility; (3) Viewing and intercom... monitors used to indicate room exposures; (6) Source positioning (accuracy); and (7) Radiation monitors...

Non-thermal effects of 94 GHz radiation on bacterial metabolism

NASA Astrophysics Data System (ADS)

Raitt, Brittany J.

Bacillus subtilis, Escherichia coli, Staphylococcus aureus, and Klebsiella pneumoniae were used to investigate the non-thermal effects of terahertz (THz) radiation exposure on bacterial cells. The THz source used was a 94 GHz (0.94 THz) Millitech Gunn Diode Oscillator with a power density of 1.3 mW/cm2. The cultures were placed in the middle sixty wells of two 96-well microplates, one serving as the experimental plate and one serving as a control. The experimental plate was placed on the radiation source for either two, eighteen, or twenty-four hours and the metabolism of the cells was measured in a spectrophotometer using the tetrazolium dye XTT. The results showed no consistent significant differences in either the growth rates or the metabolism of any of the bacterial species at this frequency and power density.

Controlling the spectral shape of nonlinear Thomson scattering with proper laser chirping

DOE PAGES

Rykovanov, S. G.; Geddes, C. G. R.; Schroeder, C. B.; ...

2016-03-18

Effects of nonlinearity in Thomson scattering of a high intensity laser pulse from electrons are analyzed. Analytic expressions for laser pulse shaping in frequency (chirping) are obtained which control spectrum broadening for high laser pulse intensities. These analytic solutions allow prediction of the spectral form and required laser parameters to avoid broadening. Results of analytical and numerical calculations agree well. The control over the scattered radiation bandwidth allows narrow bandwidth sources to be produced using high scattering intensities, which in turn greatly improves scattering yield for future x- and gamma-ray sources.

An accelerated exposure and testing apparatus for building joint sealants

NASA Astrophysics Data System (ADS)

White, C. C.; Hunston, D. L.; Tan, K. T.; Hettenhouser, J.; Garver, J. D.

2013-09-01

The design, fabrication, and implementation of a computer-controlled exposure and testing apparatus for building joint sealants are described in this paper. This apparatus is unique in its ability to independently control and monitor temperature, relative humidity, ultraviolet (UV) radiation, and mechanical deformation. Each of these environmental factors can be controlled precisely over a wide range of conditions during periods of a month or more. Moreover, as controlled mechanical deformations can be generated, in situ mechanical characterization tests can be performed without removing specimens from the chamber. Temperature and humidity were controlled during our experiments via a precision temperature regulator and proportional mixing of dry and moisture-saturated air; while highly uniform UV radiation was attained by attaching the chamber to an integrating sphere-based radiation source. A computer-controlled stepper motor and a transmission system were used to provide precise movement control. The reliability and effectiveness of the apparatus were demonstrated on a model sealant material. The results clearly show that this apparatus provides an excellent platform to study the long-term durability of building joint sealants.

An accelerated exposure and testing apparatus for building joint sealants.

PubMed

White, C C; Hunston, D L; Tan, K T; Hettenhouser, J; Garver, J D

2013-09-01

The design, fabrication, and implementation of a computer-controlled exposure and testing apparatus for building joint sealants are described in this paper. This apparatus is unique in its ability to independently control and monitor temperature, relative humidity, ultraviolet (UV) radiation, and mechanical deformation. Each of these environmental factors can be controlled precisely over a wide range of conditions during periods of a month or more. Moreover, as controlled mechanical deformations can be generated, in situ mechanical characterization tests can be performed without removing specimens from the chamber. Temperature and humidity were controlled during our experiments via a precision temperature regulator and proportional mixing of dry and moisture-saturated air; while highly uniform UV radiation was attained by attaching the chamber to an integrating sphere-based radiation source. A computer-controlled stepper motor and a transmission system were used to provide precise movement control. The reliability and effectiveness of the apparatus were demonstrated on a model sealant material. The results clearly show that this apparatus provides an excellent platform to study the long-term durability of building joint sealants.

A high-power synthesized ultrawideband radiation source

NASA Astrophysics Data System (ADS)

Efremov, A. M.; Koshelev, V. I.; Plisko, V. V.; Sevostyanov, E. A.

2017-09-01

A high-power ultrawideband radiation source has been developed which is capable of synthesizing electromagnetic pulses with different frequency bands in free space. To this end, a new circuit design comprising a four-channel former of bipolar pulses of durations 2 and 3 ns has been elaborated and conditions for the stable operation of gas gaps of independent channels without external control pulses have been determined. Each element of the 2 × 2 array of combined antennas is driven from an individual channel of the pulse former. Antennas excited by pulses of the same duration are arranged diagonally. Two radiation synthesis modes have been examined: one aimed to attain ultimate field strength and the other aimed to attain an ultimate width of the radiation spectrum. The modes were changed by changing the time delay between the 2-ns and 3-ns pulses. For the first mode, radiation pulses with a frequency band of 0.2-0.8 GHz and an effective potential of 500 kV have been obtained. The synthesized radiation pulses produced in the second mode had an extended frequency band (0.1-1 GHz) and an effective potential of 220 kV. The pulse repetition frequency was 100 Hz.

Optical Properties of Aerosols and Implications for Radiative Effects in Beijing During the Asia-Pacific Economic Cooperation Summit 2014

NASA Astrophysics Data System (ADS)

Zhou, Yaqing; Wang, Qiyuan; Huang, Rujin; Liu, Suixin; Tie, Xuexi; Su, Xiaoli; Niu, Xinyi; Zhao, Zhuzi; Ni, Haiyan; Wang, Meng; Zhang, Yonggang; Cao, Junji

2017-09-01

An intensive measurement campaign was conducted in Beijing during the Asia-Pacific Economic Cooperation (APEC) Summit 2014 to investigate the effectiveness of stringent emission controls on aerosol optical properties and direct radiative forcing (DRF). Average values of PM2.5, light scattering (bscat), and light absorption (babs) coefficients decreased by 40, 64, and 56%, respectively, during the APEC control period compared with noncontrol periods. For the APEC control period, the PM2.5 mass scattering and absorption efficiencies were both smaller than the noncontrol period by a factor of 2. Calculations based on a revised IMPROVE method and linear regression showed that sulfate, nitrate, organic matter, elemental carbon, and fine soil contributed comparably to the light extinction coefficient (bext) in both periods, but the bext values were 27-64% lower during the APEC period. A positive matrix factorization receptor model showed that bext from two secondary aerosol sources, biomass burning, traffic-related emissions, and coal burning decreased by 26-87% during the APEC control period. The average DRF calculated from the Tropospheric Ultraviolet and Visible radiation model was -11.9 and -4.6 W m-2 at the surface during the noncontrol and APEC control periods, respectively, suggesting an overall cooling effect. The reduction of DRF from each emission source ranged from 30-80% during the APEC control period. The results suggest that the pollution control measures implemented for APEC substantially reduced air pollution and could help mitigate the cooling effects of aerosols at the surface in Beijing.

A wavenumber approach to analysing the active control of plane waves with arrays of secondary sources

NASA Astrophysics Data System (ADS)

Elliott, Stephen J.; Cheer, Jordan; Bhan, Lam; Shi, Chuang; Gan, Woon-Seng

2018-04-01

The active control of an incident sound field with an array of secondary sources is a fundamental problem in active control. In this paper the optimal performance of an infinite array of secondary sources in controlling a plane incident sound wave is first considered in free space. An analytic solution for normal incidence plane waves is presented, indicating a clear cut-off frequency for good performance, when the separation distance between the uniformly-spaced sources is equal to a wavelength. The extent of the near field pressure close to the source array is also quantified, since this determines the positions of the error microphones in a practical arrangement. The theory is also extended to oblique incident waves. This result is then compared with numerical simulations of controlling the sound power radiated through an open aperture in a rigid wall, subject to an incident plane wave, using an array of secondary sources in the aperture. In this case the diffraction through the aperture becomes important when its size is compatible with the acoustic wavelength, in which case only a few sources are necessary for good control. When the size of the aperture is large compared to the wavelength, and diffraction is less important but more secondary sources need to be used for good control, the results then become similar to those for the free field problem with an infinite source array.

Radiation exposures due to fossil fuel combustion

NASA Astrophysics Data System (ADS)

Beck, Harold L.

The current consensus regarding the potential radiation exposures resulting from the combustion of fossil fuels is examined. Sources, releases and potential doses to humans are discussed, both for power plants and waste materials. It is concluded that the radiation exposure to most individuals from any pathway is probably insignificant, i.e. only a tiny fraction of the dose received from natural sources in soil and building materials. Any small dose that may result from power-plant emissions will most likely be from inhalation of the small insoluble ash particles from the more poorly controlled plants burning higher than average activity fuel, rather than from direct or indirect ingestion of food grown on contaminated soil. One potentially significant pathway for exposure to humans that requires further evaluation is the effect on indoor external γ-radiation levels resulting from the use of flyash in building materials. The combustion of natural gas in private dwellings is also discussed, and the radiological consequences are concluded to be generally insignificant, except under certain extraordinary circumstances.

Compact optical transconductance varistor

DOEpatents

Sampayan, Stephen

2015-09-22

A compact radiation-modulated transconductance varistor device having both a radiation source and a photoconductive wide bandgap semiconductor material (PWBSM) integrally formed on a substrate so that a single interface is formed between the radiation source and PWBSM for transmitting PWBSM activation radiation directly from the radiation source to the PWBSM.

High-speed furnace uses infrared radiation for controlled brazing

NASA Technical Reports Server (NTRS)

Eckles, P. N.

1966-01-01

Furnace produces controlled heat for brazing and heat treating metals over a wide range of temperatures by using a near-infrared heat source positioned at one focus of an ellipsoidal reflector mounted below a cylindrical quartz chamber. This furnace maintains a pure atmosphere, has rapid heatup and cooldown, and permits visual observation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaffney, Jeffrey

This is the final technical report. The project description is as follows: to determine the role of aerosol radiative forcing on climate, the processes that control their atmospheric concentrations must be understood, and aerosol sources need to be determined for mitigation. Measurements of naturally occurring radionuclides and stable isotopic signatures allow the sources, removal and transport processes, as well as atmospheric lifetimes of fine carbonaceous aerosols, to be evaluated.

Injecting Artificial Memory Errors Into a Running Computer Program

NASA Technical Reports Server (NTRS)

Bornstein, Benjamin J.; Granat, Robert A.; Wagstaff, Kiri L.

2008-01-01

Single-event upsets (SEUs) or bitflips are computer memory errors caused by radiation. BITFLIPS (Basic Instrumentation Tool for Fault Localized Injection of Probabilistic SEUs) is a computer program that deliberately injects SEUs into another computer program, while the latter is running, for the purpose of evaluating the fault tolerance of that program. BITFLIPS was written as a plug-in extension of the open-source Valgrind debugging and profiling software. BITFLIPS can inject SEUs into any program that can be run on the Linux operating system, without needing to modify the program s source code. Further, if access to the original program source code is available, BITFLIPS offers fine-grained control over exactly when and which areas of memory (as specified via program variables) will be subjected to SEUs. The rate of injection of SEUs is controlled by specifying either a fault probability or a fault rate based on memory size and radiation exposure time, in units of SEUs per byte per second. BITFLIPS can also log each SEU that it injects and, if program source code is available, report the magnitude of effect of the SEU on a floating-point value or other program variable.

Growth and photomorphogenesis of pepper plants under red light-emitting diodes with supplemental blue or far-red lighting

NASA Technical Reports Server (NTRS)

Brown, C. S.; Schuerger, A. C.; Sager, J. C.

1995-01-01

Light-emitting diodes (LEDs) are a potential irradiation source for intensive plant culture systems and photobiological research. They have small size, low mass, a long functional life, and narrow spectral output. In this study, we measured the growth and dry matter partitioning of 'Hungarian Wax' pepper (Capsicum annuum L.) plants grown under red LEDs compared with similar plants grown under red LEDs with supplemental blue or far-red radiation or under broad spectrum metal halide (MH) lamps. Additionally, we describe the thermal and spectral characteristics of these sources. The LEDs used in this study had a narrow bandwidth at half peak height (25 nm) and a focused maximum spectral output at 660 nm for the red and 735 nm for the far-red. Near infrared radiation (800 to 3000 nm) was below detection and thermal infrared radiation (3000 to 50,000 nm) was lower in the LEDs compared to the MH source. Although the red to far-red ratio varied considerably, the calculated phytochrome photostationary state (phi) was only slightly different between the radiation sources. Plant biomass was reduced when peppers were grown under red LEDs in the absence of blue wavelengths compared to plants grown under supplemental blue fluorescent lamps or MH lamps. The addition of far-red radiation resulted in taller plants with greater stem mass than red LEDs alone. There were fewer leaves under red or red plus far-red radiation than with lamps producing blue wavelengths. These results indicate that red LEDs may be suitable, in proper combination with other wavelengths of light, for the culture of plants in tightly controlled environments such as space-based plant culture systems.

Implementation of ionizing radiation environment requirements for Space Station

NASA Technical Reports Server (NTRS)

Boeder, Paul A.; Watts, John W.

1993-01-01

Proper functioning of Space Station hardware requires that the effects of high-energy ionizing particles from the natural environment and (possibly) from man-made sources be considered during design. At the Space Station orbit of 28.5-deg inclination and 330-440 km altitude, geomagnetically trapped protons and electrons contribute almost all of the dose, while galactic cosmic rays and anomalous cosmic rays may produce Single Event Upsets (SEUs), latchups, and burnouts of microelectronic devices. Implementing ionizing radiation environment requirements for Space Station has been a two part process, including the development of a description of the environment for imposing requirements on the design and the development of a control process for assessing how well the design addresses the effects of the ionizing radiation environment. We will review both the design requirements and the control process for addressing ionizing radiation effects on Space Station.

Frequency-controls of electromagnetic multi-beam scanning by metasurfaces.

PubMed

Li, Yun Bo; Wan, Xiang; Cai, Ben Geng; Cheng, Qiang; Cui, Tie Jun

2014-11-05

We propose a method to control electromagnetic (EM) radiations by holographic metasurfaces, including to producing multi-beam scanning in one dimension (1D) and two dimensions (2D) with the change of frequency. The metasurfaces are composed of subwavelength metallic patches on grounded dielectric substrate. We present a combined theory of holography and leaky wave to realize the multi-beam radiations by exciting the surface interference patterns, which are generated by interference between the excitation source and required radiation waves. As the frequency changes, we show that the main lobes of EM radiation beams could accomplish 1D or 2D scans regularly by using the proposed holographic metasurfaces shaped with different interference patterns. This is the first time to realize 2D scans of antennas by changing the frequency. Full-wave simulations and experimental results validate the proposed theory and confirm the corresponding physical phenomena.

Investigation of Carbonaceous Aerosol Optical Properties to Understand Impacts on Air Quality and Composition

NASA Astrophysics Data System (ADS)

Olson, Michael R.

The optical properties of carbonaceous aerosols were investigated to understand the impact source emissions and ambient particulate matter (PM) have on atmospheric radiative forcing. Black carbon (BC) is a strong absorber of visible light and contributes highly to atmospheric radiative forcing, therefore it is important to link BC properties to combustion emission sources. Brown carbon (BrC) is poorly understood and may be an important contributor to both positive and negative radiative forcing. The research investigates these primary knowledge gaps. The optical properties of carbonaceous aerosols were investigated to understand the impact source emissions and ambient particulate matter (PM) have on atmospheric radiative forcing. Black carbon (BC) is a strong absorber of visible light and contributes highly to atmospheric radiative forcing, therefore it is important to link BC properties to combustion emission sources. Brown carbon (BrC) is poorly understood and may be an important contributor to both positive and negative radiative forcing. The research investigates these primary knowledge gaps. Multiple methods were developed and applied to quantify the mass absorption cross-section (MAC) at multiple wavelengths of source and ambient samples. The MAC of BC was determined to be approximately 7.5 m2g-1 at 520nm. However, the MAC was highly variable with OC fraction and wavelength. The BrC MAC was similar for all sources, with the highest absorption in the UV at 370nm; the MAC quickly decreases at larger wavelengths. In the UV, the light absorption by BrC could exceed BC contribution by over 100 times, but only when the OC fraction is large (>90%) as compared to the total carbon. BrC was investigated by measuring the light absorption of solvent extracted fractions in water, dichloromethane, and methanol. Source emissions exhibited greater light absorption in methanol extractions as compared to water and DCM extracts. The BrC MAC was 2.4 to 3.7 m2g-1 at 370nm in methanol. Ambient samples showed similar MACs for the water and methanol extracts. Dichloromethane extracts did not have a significant light absorption characteristics for ambient samples. BrC and BC were measured in Beijing, China. Both were reduced significantly when restrictive air pollution controls were put in place. The industrial regions south and east of Beijing were the highest contributors to ambient BrC and BC. The controls reduced BrC more than BC as compared to observations during the regions heating period. Using the color characteristics of ambient PM, a model was developed to estimate elemental and organic carbon (EC/OC). The method will allow fast and cost effective quantification of PM composition in combination with large climate and health studies, especially in the developing world.

Apparatus and method for detecting gamma radiation

DOEpatents

Sigg, Raymond A.

1994-01-01

A high efficiency radiation detector for measuring X-ray and gamma radiation from small-volume, low-activity liquid samples with an overall uncertainty better than 0.7% (one sigma SD). The radiation detector includes a hyperpure germanium well detector, a collimator, and a reference source. The well detector monitors gamma radiation emitted by the reference source and a radioactive isotope or isotopes in a sample source. The radiation from the reference source is collimated to avoid attenuation of reference source gamma radiation by the sample. Signals from the well detector are processed and stored, and the stored data is analyzed to determine the radioactive isotope(s) content of the sample. Minor self-attenuation corrections are calculated from chemical composition data.

How to Integrate Variable Power Source into a Power Grid

NASA Astrophysics Data System (ADS)

Asano, Hiroshi

This paper discusses how to integrate variable power source such as wind power and photovoltaic generation into a power grid. The intermittent renewable generation is expected to penetrate for less carbon intensive power supply system, but it causes voltage control problem in the distribution system, and supply-demand imbalance problem in a whole power system. Cooperative control of customers' energy storage equipment such as water heater with storage tank for reducing inverse power flow from the roof-top PV system, the operation technique using a battery system and the solar radiation forecast for stabilizing output of variable generation, smart charging of plug-in hybrid electric vehicles for load frequency control (LFC), and other methods to integrate variable power source with improving social benefits are surveyed.

Radioactive source security: the cultural challenges.

PubMed

Englefield, Chris

2015-04-01

Radioactive source security is an essential part of radiation protection. Sources can be abandoned, lost or stolen. If they are stolen, they could be used to cause deliberate harm and the risks are varied and significant. There is a need for a global security protection system and enhanced capability to achieve this. The establishment of radioactive source security requires 'cultural exchanges'. These exchanges include collaboration between: radiation protection specialists and security specialists; the nuclear industry and users of radioactive sources; training providers and regulators/users. This collaboration will facilitate knowledge and experience exchange for the various stakeholder groups, beyond those already provided. This will promote best practice in both physical and information security and heighten security awareness generally. Only if all groups involved are prepared to open their minds to listen to and learn from, each other will a suitable global level of control be achieved. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Modeling of neutrals in the Linac4 H- ion source plasma: Hydrogen atom production density profile and Hα intensity by collisional radiative model

NASA Astrophysics Data System (ADS)

Yamamoto, T.; Shibata, T.; Ohta, M.; Yasumoto, M.; Nishida, K.; Hatayama, A.; Mattei, S.; Lettry, J.; Sawada, K.; Fantz, U.

2014-02-01

To control the H0 atom production profile in the H- ion sources is one of the important issues for the efficient and uniform surface H- production. The purpose of this study is to construct a collisional radiative (CR) model to calculate the effective production rate of H0 atoms from H2 molecules in the model geometry of the radio-frequency (RF) H- ion source for Linac4 accelerator. In order to validate the CR model by comparison with the experimental results from the optical emission spectroscopy, it is also necessary for the model to calculate Balmer photon emission rate in the source. As a basic test of the model, the time evolutions of H0 production and the Balmer Hα photon emission rate are calculated for given electron energy distribution functions in the Linac4 RF H- ion source. Reasonable test results are obtained and basis for the detailed comparisons with experimental results have been established.

Space shuttle heat pipe thermal control systems

NASA Technical Reports Server (NTRS)

Alario, J.

1973-01-01

Heat pipe (HP) thermal control systems designed for possible space shuttle applications were built and tested under this program. They are: (1) a HP augmented cold rail, (2) a HP/phase change material (PCM) modular heat sink and (3) a HP radiating panel for compartment temperature control. The HP augmented cold rail is similar to a standard two-passage fluid cold rail except that it contains an integral, centrally located HP throughout its length. The central HP core helps to increase the local power density capability by spreading concentrated heat inputs over the entire rail. The HP/PCM modular heat sink system consists of a diode HP connected in series to a standard HP that has a PCM canister attached to its mid-section. It is designed to connect a heat source to a structural heat sink during normal operation, and to automatically decouple from it and sink to the PCM whenever structural temperatures are too high. The HP radiating panel is designed to conductively couple the panel feeder HPs directly to a fluid line that serves as a source of waste heat. It is a simple strap-on type of system that requires no internal or external line modifications to distribute the heat to a large radiating area.

Tapered monocapillary-optics for point source applications

DOEpatents

Hirsch, Gregory

2000-01-01

A glass or metal wire is precisely etched to form the paraboloidal or ellipsoidal shape of the final desired capillary optic. This shape is created by carefully controlling the withdrawal speed of the wire from an etchant bath. In the case of a complete ellipsoidal capillary, the etching operation is performed twice in opposite directions on adjacent wire segments. The etched wire undergoes a subsequent operation to create an extremely smooth surface. This surface is coated with a layer of material which is selected to maximize the reflectivity of the radiation. This reflective surface may be a single layer for wideband reflectivity, or a multilayer coating for optimizing the reflectivity in a narrower wavelength interval. The coated wire is built up with a reinforcing layer, typically by a plating operation. The initial wire is removed by either an etching procedure or mechanical force. Prior to removing the wire, the capillary is typically bonded to a support substrate. One option for attaching the wire to the substrate produces a monolithic structure by essentially burying it under a layer of plating which covers both the wire and the substrate. The capillary optic is used for efficiently collecting and redirecting the divergent radiation from a source which could be the anode of an x-ray tube, a plasma source, the fluorescent radiation from an electron microprobe, or some other source of radiation.

Method and system for determining radiation shielding thickness and gamma-ray energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klann, Raymond T.; Vilim, Richard B.; de la Barrera, Sergio

2015-12-15

A system and method for determining the shielding thickness of a detected radiation source. The gamma ray spectrum of a radiation detector is utilized to estimate the shielding between the detector and the radiation source. The determination of the shielding may be used to adjust the information from known source-localization techniques to provide improved performance and accuracy of locating the source of radiation.

Radiological protection, safety and security issues in the industrial and medical applications of radiation sources

NASA Astrophysics Data System (ADS)

Vaz, Pedro

2015-11-01

The use of radiation sources, namely radioactive sealed or unsealed sources and particle accelerators and beams is ubiquitous in the industrial and medical applications of ionizing radiation. Besides radiological protection of the workers, members of the public and patients in routine situations, the use of radiation sources involves several aspects associated to the mitigation of radiological or nuclear accidents and associated emergency situations. On the other hand, during the last decade security issues became burning issues due to the potential malevolent uses of radioactive sources for the perpetration of terrorist acts using RDD (Radiological Dispersal Devices), RED (Radiation Exposure Devices) or IND (Improvised Nuclear Devices). A stringent set of international legally and non-legally binding instruments, regulations, conventions and treaties regulate nowadays the use of radioactive sources. In this paper, a review of the radiological protection issues associated to the use of radiation sources in the industrial and medical applications of ionizing radiation is performed. The associated radiation safety issues and the prevention and mitigation of incidents and accidents are discussed. A comprehensive discussion of the security issues associated to the global use of radiation sources for the aforementioned applications and the inherent radiation detection requirements will be presented. Scientific, technical, legal, ethical, socio-economic issues are put forward and discussed.

An improved DPSM technique for modelling ultrasonic fields in cracked solids

NASA Astrophysics Data System (ADS)

Banerjee, Sourav; Kundu, Tribikram; Placko, Dominique

2007-04-01

In recent years Distributed Point Source Method (DPSM) is being used for modelling various ultrasonic, electrostatic and electromagnetic field modelling problems. In conventional DPSM several point sources are placed near the transducer face, interface and anomaly boundaries. The ultrasonic or the electromagnetic field at any point is computed by superimposing the contributions of different layers of point sources strategically placed. The conventional DPSM modelling technique is modified in this paper so that the contributions of the point sources in the shadow region can be removed from the calculations. For this purpose the conventional point sources that radiate in all directions are replaced by Controlled Space Radiation (CSR) sources. CSR sources can take care of the shadow region problem to some extent. Complete removal of the shadow region problem can be achieved by introducing artificial interfaces. Numerically synthesized fields obtained by the conventional DPSM technique that does not give any special consideration to the point sources in the shadow region and the proposed modified technique that nullifies the contributions of the point sources in the shadow region are compared. One application of this research can be found in the improved modelling of the real time ultrasonic non-destructive evaluation experiments.

32 CFR 655.10 - Use of radiation sources by non-Army entities on Army land (AR 385-11).

Code of Federal Regulations, 2010 CFR

2010-07-01

... radioisotope; or (5) A machine-produced ionizing-radiation source capable of producing an area, accessible to... NARM and machine-produced ionizing radiation sources, the applicant has an appropriate State... 32 National Defense 4 2010-07-01 2010-07-01 true Use of radiation sources by non-Army entities on...

Determination of Jet Noise Radiation Source Locations using a Dual Sideline Cross-Correlation/Spectrum Technique

NASA Technical Reports Server (NTRS)

Allen, C. S.; Jaeger, S. M.

1999-01-01

The goal of our efforts is to extrapolate nearfield jet noise measurements to the geometric far field where the jet noise sources appear to radiate from a single point. To accomplish this, information about the location of noise sources in the jet plume, the radiation patterns of the noise sources and the sound pressure level distribution of the radiated field must be obtained. Since source locations and radiation patterns can not be found with simple single microphone measurements, a more complicated method must be used.

Transmission and scattering of acoustic energy in turbulent flows

NASA Astrophysics Data System (ADS)

Gaitonde, Datta; Unnikrishnan, S.

2017-11-01

Sound scattering and transmission in turbulent jets are explored through a control volume analysis of a Large-Eddy Simulation. The fluctuating momentum flux across any control surface is first split into its rotational turbulent ((ρu)'H) and the irrotational-isentropic acoustic ((ρu)'A) components using momentum potential theory (MPT). The former has low spatio-temporal coherence, while the latter exhibits a persistent wavepacket form. The energy variable, specifically, total fluctuating enthalpy, is also split into its turbulent and acoustic modes, HH' and HA' respectively. Scattering of acoustic energy is then (ρu)'HHA' , and transmission is (ρu)'AHA' . This facilitates a quantitative comparison of scattering versus transmission in the presence of acoustic energy sources, also obtained from MPT, in any turbulent scenario. The wavepacket converts stochastic sound sources into coherent sound radiation. Turbulent eddies are not only sources of sound, but also play a strong role in scattering, particularly near the lipline. The net acoustic flux from the jet is the transport of HA' by the wavepacket, whose axisymmetric and higher azimuthal modes contribute to downstream and sideline radiation respectively.

Specificity and Heterogeneity of Terahertz Radiation Effect on Gene Expression in Mouse Mesenchymal Stem Cells

DOE PAGES

Alexandrov, Boian S.; Phipps, M. Lisa; Alexandrov, Ludmil B.; ...

2013-01-31

In this paper, we report that terahertz (THz) irradiation of mouse mesenchymal stem cells (mMSCs) with a single-frequency (SF) 2.52 THz laser or pulsed broadband (centered at 10 THz) source results in irradiation specific heterogenic changes in gene expression. The THz effect depends on irradiation parameters such as the duration and type of THz source, and on the degree of stem cell differentiation. Our microarray survey and RT-PCR experiments demonstrate that prolonged broadband THz irradiation drives mMSCs toward differentiation, while 2-hour irradiation (regardless of THz sources) affects genes transcriptionally active in pluripotent stem cells. The strictly controlled experimental environment indicatesmore » minimal temperature changes and the absence of any discernable response to heat shock and cellular stress genes imply a non-thermal response. Computer simulations of the core promoters of two pluripotency markers reveal association between gene upregulation and propensity for DNA breathing. Finally, we propose that THz radiation has potential for non-contact control of cellular gene expression.« less

Trans-oral miniature X-ray radiation delivery system with endoscopic optical feedback.

PubMed

Boese, Axel; Johnson, Fredrick; Ebert, Till; Mahmoud-Pashazadeh, Ali; Arens, Christoph; Friebe, Michael

2017-11-01

Surgery, chemo- and/or external radiation therapy are the standard therapy options for the treatment of laryngeal cancer. Trans-oral access for the surgery reduces traumata and hospitalization time. A new trend in treatment is organ-preserving surgery. To avoid regrowth of cancer, this type of surgery can be combined with radiation therapy. Since external radiation includes healthy tissue surrounding the cancerous zone, a local and direct intraoral radiation delivery would be beneficial. A general concept for a trans-oral radiation system was designed, based on clinical need identification with a medical user. A miniaturized X-ray tube was used as the radiation source for the intraoperative radiation delivery. To reduce dose distribution on healthy areas, the X-ray source was collimated by a newly designed adjustable shielding system as part of the housing. For direct optical visualization of the radiation zone, a miniature flexible endoscope was integrated into the system. The endoscopic light cone and the field of view were aligned with the zone of the collimated radiation. The intraoperative radiation system was mounted on a semi-automatic medical holder that was combined with a frontal actuator for rotational and translational movement using piezoelectric motors to provide precise placement. The entire technical set-up was tested in a simulated environment. The shielding of the X-ray source was verified by performing conventional detector-based dose measurements. The delivered dose was estimated by an ionization chamber. The adjustment of the radiation zone was performed by a manual controlling mechanism integrated into the hand piece of the device. An endoscopic fibre was also added to offer visualization and illumination of the radiation zone. The combination of the radiation system with the semi-automatic holder and actuator offered precise and stable positioning of the device in range of micrometres and will allow for future combination with a radiation planning system. The presented system was designed for radiation therapy of the oral cavity and the larynx. This first set-up tried to cover all clinical aspects that are necessary for a later use in surgery. The miniaturized X-ray tube offers the size and the power for intraoperative radiation therapy. The adjustable shielding system in combination with the holder and actuator provides a precise placement. The visualization of radiation zone allows a targeting and observation of the radiation zone.

Apparatus and method for detecting gamma radiation

DOEpatents

Sigg, R.A.

1994-12-13

A high efficiency radiation detector is disclosed for measuring X-ray and gamma radiation from small-volume, low-activity liquid samples with an overall uncertainty better than 0.7% (one sigma SD). The radiation detector includes a hyperpure germanium well detector, a collimator, and a reference source. The well detector monitors gamma radiation emitted by the reference source and a radioactive isotope or isotopes in a sample source. The radiation from the reference source is collimated to avoid attenuation of reference source gamma radiation by the sample. Signals from the well detector are processed and stored, and the stored data is analyzed to determine the radioactive isotope(s) content of the sample. Minor self-attenuation corrections are calculated from chemical composition data. 4 figures.

[Application of THz technology to nondestructive detection of agricultural product quality].

PubMed

Jiang, Yu-ying; Ge, Hong-yi; Lian, Fei-yu; Zhang, Yuan; Xia, Shan-hong

2014-08-01

With recent development of THz sources and detector, applications of THz radiation to nondestructive testing and quality control have expanded in many fields, such as agriculture, safety inspection and quality control, medicine, biochemistry, communication etc. Compared with other detection technique, being a new kind of technique, THz radiation has low energy, good perspectivity, and high signal-to-noise ratio, and thus can obtain physical, chemical and biological information. This paper first introduces the basic concept of THz radiation and the major properties, then gives an extensive review of recent research progress in detection of the quality of agricultural products via THz technique, analyzes the existing shortcomings of THz detection and discusses the outlook of potential application, finally proposes the new application of THz technique to detection of quality of stored grain.

Cluster beam targets for laser plasma extreme ultraviolet and soft x-ray sources

DOEpatents

Kublak, G.D.; Richardson, M.C.

1996-11-19

Method and apparatus for producing extreme ultraviolet (EUV) and soft x-ray radiation from an ultra-low debris plasma source are disclosed. Targets are produced by the free jet expansion of various gases through a temperature controlled nozzle to form molecular clusters. These target clusters are subsequently irradiated with commercially available lasers of moderate intensity (10{sup 11}--10{sup 12} watts/cm{sup 2}) to produce a plasma radiating in the region of 0.5 to 100 nanometers. By appropriate adjustment of the experimental conditions the laser focus can be moved 10--30 mm from the nozzle thereby eliminating debris produced by plasma erosion of the nozzle. 5 figs.

Cluster beam targets for laser plasma extreme ultraviolet and soft x-ray sources

DOEpatents

Kublak, Glenn D.; Richardson, Martin C. (CREOL

1996-01-01

Method and apparatus for producing extreme ultra violet (EUV) and soft x-ray radiation from an ultra-low debris plasma source are disclosed. Targets are produced by the free jet expansion of various gases through a temperature controlled nozzle to form molecular clusters. These target clusters are subsequently irradiated with commercially available lasers of moderate intensity (10.sup.11 -10.sup.12 watts/cm.sup.2) to produce a plasma radiating in the region of 0.5 to 100 nanometers. By appropriate adjustment of the experimental conditions the laser focus can be moved 10-30 mm from the nozzle thereby eliminating debris produced by plasma erosion of the nozzle.

Solid-state radiation-emitting compositions and devices

DOEpatents

Ashley, Carol S.; Brinker, C. Jeffrey; Reed, Scott; Walko, Robert J.

1992-01-01

The invention relates to a composition for the volumetric generation of radiation, wherein a first substance functions as a source of exciting radiation, and a second substance interacts with the exciting radiation to provide a second radiation. The compositions comprise a porous substrate which is loaded with: a source of exciting radiation, a component capable of emitting radiation upon interaction with the exciting radiation, or both. Preferably, the composition is an aerogel substrate loaded with both a source of exciting radiation, such as tritium, and a component capable of interacting with the exciting radiation, e.g., a phosphor, to produce radiation of a second energy.

Solid-state radiation-emitting compositions and devices

DOEpatents

Ashley, C.S.; Brinker, C.J.; Reed, S.; Walko, R.J.

1992-08-11

The invention relates to a composition for the volumetric generation of radiation, wherein a first substance functions as a source of exciting radiation, and a second substance interacts with the exciting radiation to provide a second radiation. The compositions comprise a porous substrate which is loaded with: a source of exciting radiation, a component capable of emitting radiation upon interaction with the exciting radiation, or both. Preferably, the composition is an aerogel substrate loaded with both a source of exciting radiation, such as tritium, and a component capable of interacting with the exciting radiation, e.g., a phosphor, to produce radiation of a second energy. 4 figs.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rogers, D.M.; Coggins, T.L.; Marsh, J.

Numerous efforts are funded by US agencies (DOE, DoD, DHS) for development of novel radiation sensing and measurement systems. An effort has been undertaken to develop a flexible shielding system compatible with a variety of sources (beta, X-ray, gamma, and neutron) that can be highly characterized using conventional radiation detection and measurement systems. Sources available for use in this system include americium-beryllium (AmBe), plutonium-beryllium (PuBe), strontium-90 (Sr-90), californium-252 (Cf-252), krypton-85 (Kr-85), americium-241 (Am-241), and depleted uranium (DU). Shielding can be varied by utilization of materials that include lexan, water, oil, lead, and polyethylene. Arrangements and geometries of source(s) and shieldingmore » can produce symmetrical or asymmetrical radiation fields. The system has been developed to facilitate accurately repeatable configurations. Measurement positions are similarly capable of being accurately re-created. Stand-off measurement positions can be accurately re-established using differential global positioning system (GPS) navigation. Instruments used to characterize individual measurement locations include a variety of sodium iodide (NaI(Tl)) (3 x 3 inch, 4 x 4 x 16 inch, Fidler) and lithium iodide (LiI(Eu)) detectors (for use with multichannel analyzer software) and detectors for use with traditional hand held survey meters such as boron trifluoride (BF{sub 3}), helium-3 ({sup 3}He), and Geiger-Mueller (GM) tubes. Also available are Global Dosimetry thermoluminescent dosimeters (TLDs), CR39 neutron chips, and film badges. Data will be presented comparing measurement techniques with shielding/source configurations. The system is demonstrated to provide a highly functional process for comparison/characterization of various detector types relative to controllable radiation types and levels. Particular attention has been paid to use of neutron sources and measurements. (authors)« less

The influence of high intensity terahertz radiation on mammalian cell adhesion, proliferation and differentiation.

PubMed

Williams, Rachel; Schofield, Amy; Holder, Gareth; Downes, Joan; Edgar, David; Harrison, Paul; Siggel-King, Michele; Surman, Mark; Dunning, David; Hill, Stephen; Holder, David; Jackson, Frank; Jones, James; McKenzie, Julian; Saveliev, Yuri; Thomsen, Neil; Williams, Peter; Weightman, Peter

2013-01-21

Understanding the influence of exposure of biological systems to THz radiation is becoming increasingly important. There is some evidence to suggest that THz radiation can influence important activities within mammalian cells. This study evaluated the influence of the high peak power, low average power THz radiation produced by the ALICE (Daresbury Laboratory, UK) synchrotron source on human epithelial and embryonic stem cells. The cells were maintained under standard tissue culture conditions, during which the THz radiation was delivered directly into the incubator for various exposure times. The influence of the THz radiation on cell morphology, attachment, proliferation and differentiation was evaluated. The study demonstrated that there was no difference in any of these parameters between irradiated and control cell cultures. It is suggested that under these conditions the cells are capable of compensating for any effects caused by exposure to THz radiation with the peak powers levels employed in these studies.

Spectral and spatial shaping of Smith-Purcell radiation

NASA Astrophysics Data System (ADS)

Remez, Roei; Shapira, Niv; Roques-Carmes, Charles; Tirole, Romain; Yang, Yi; Lereah, Yossi; Soljačić, Marin; Kaminer, Ido; Arie, Ady

2017-12-01

The Smith-Purcell effect, observed when an electron beam passes in the vicinity of a periodic structure, is a promising platform for the generation of electromagnetic radiation in previously unreachable spectral ranges. However, most of the studies of this radiation were performed on simple periodic gratings, whose radiation spectrum exhibits a single peak and its higher harmonics predicted by a well-established dispersion relation. Here, we propose a method to shape the spatial and spectral far-field distribution of the radiation using complex periodic and aperiodic gratings. We show, theoretically and experimentally, that engineering multiple peak spectra with controlled widths located at desired wavelengths is achievable using Smith-Purcell radiation. Our method opens the way to free-electron-driven sources with tailored angular and spectral responses, and gives rise to focusing functionality for spectral ranges where lenses are unavailable or inefficient.

75 FR 19302 - Radiation Sources on Army Land

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-14

... Nuclear Regulatory Commission (NRC) license or Army Radiation Authorization (ARA). The purpose of the ARP...-0001] Radiation Sources on Army Land AGENCY: Department of the Army, DoD. ACTION: Proposed rule... radiation sources on Army land. The Army requires Non-Army agencies (including their civilian contractors...

Solar cosmic rays as a specific source of radiation risk during piloted space flight.

PubMed

Petrov, V M

2004-01-01

Solar cosmic rays present one of several radiation sources that are unique to space flight. Under ground conditions the exposure to individuals has a controlled form and radiation risk occurs as stochastic radiobiological effects. Existence of solar cosmic rays in space leads to a stochastic mode of radiation environment as a result of which any radiobiological consequences of exposure to solar cosmic rays during the flight will be probabilistic values. In this case, the hazard of deterministic effects should also be expressed in radiation risk values. The main deterministic effect under space conditions is radiation sickness. The best dosimetric functional for its analysis is the blood forming organs dose equivalent but not an effective dose. In addition, the repair processes in red bone marrow affect strongly on the manifestation of this pathology and they must be taken into account for radiation risk assessment. A method for taking into account the mentioned above peculiarities for the solar cosmic rays radiation risk assessment during the interplanetary flights is given in the report. It is shown that radiation risk of deterministic effects defined, as the death probability caused by radiation sickness due to acute solar cosmic rays exposure, can be comparable to risk of stochastic effects. Its value decreases strongly because of the fractional mode of exposure during the orbital movement of the spacecraft. On the contrary, during the interplanetary flight, radiation risk of deterministic effects increases significantly because of the residual component of the blood forming organs dose from previous solar proton events. The noted quality of radiation responses must be taken into account for estimating radiation hazard in space. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

An environmental dose experiment

NASA Astrophysics Data System (ADS)

Peralta, Luis

2017-11-01

Several radiation sources worldwide contribute to the delivered dose to the human population. This radiation also acts as a natural background when detecting radiation, for instance from radioactive sources. In this work a medium-sized plastic scintillation detector is used to evaluate the dose delivered by natural radiation sources. Calibration of the detector involved the use of radioactive sources and Monte Carlo simulation of the energy deposition per disintegration. A measurement of the annual dose due to background radiation to the body was then estimated. A dose value compatible with the value reported by the United Nations Scientific Committee on the Effects of Atomic Radiation was obtained.

Theoretical overview and modeling of the sodium and potassium atmospheres of mercury

NASA Technical Reports Server (NTRS)

Smyth, William H.; Marconi, M. L.

1995-01-01

A general theoretical overview for the sources, sinks, gas-surface interactions, and transport dynamics of sodium and potassium in the exospheric atmsophere of Mercury is given. Information for these four factors, which control the spatial distribution of these two alkali-group gases about the planet, is incorporated in numerical models. The spatial nature and relative importance of the initial source atom atmosphere and the ambient (ballistic hopping) atom atmosphere are then examined and are shown to be controlled and coupled to a great extent by the extremely large and variable solar radiation acceleration experienced by sodium and potassium as they resonantly scatter solar photons. The lateral (antisunward) transport rate of thermally accommodated sodium and potassium ambient atoms is shown to be driven by the solar radiation acceleration and, over a significant portion of Mercury's orbit about the Sun, is sufficiently rapid to be competitive with the short photoionization lifetimes for these atoms when they are located on the summit surface near or within about 30 deg of the terminator. The lateral transport rate is characterized by a migration time determined by model calculations for an ensemble of atoms initially starting at a point source on the surface (i.e., a numerical spacetime dependent Green's function). Four animations for the spacetime evolution of the sodium (or potassium) atmosphere produced by a point source on the surface are presented on a videotape format. For extended surface sources for sodium and potassium, the local column density is determined by competition between the photoionization lifetimes and the lateral transport times of atoms originating from different surface source locations. Sodium surface source fluxes (referenced to Mercury at perihelion) that are required on the sunlit hemisphere to reproduce the typically observed several megarayleighs of D2 emission-line brightness and the inferred column densities of 1-2 x 10(exp 11) atoms per sq cm range from approximately 2-5 x 10(exp 7) atoms/sq cm/sec. The sodium model is applied to study observational data that document an anticorrelation in the average sodium column density and solar radiation acceleration. Lateral transport driven by the solar radiation acceleration is shown to produce this behavior for combinations of different sources and surface accomodation coefficients. The best fit model fits to the observational data require a significant degree of thermal accommodation of the ambient sodium atoms to the surface and a source rate that decreases as an inverse power of 1.5 to 2 in heliocentric distance.

Lithographic VCSEL array multimode and single mode sources for sensing and 3D imaging

NASA Astrophysics Data System (ADS)

Leshin, J.; Li, M.; Beadsworth, J.; Yang, X.; Zhang, Y.; Tucker, F.; Eifert, L.; Deppe, D. G.

2016-05-01

Sensing applications along with free space data links can benefit from advanced laser sources that produce novel radiation patterns and tight spectral control for optical filtering. Vertical-cavity surface-emitting lasers (VCSELs) are being developed for these applications. While oxide VCSELs are being produced by most companies, a new type of oxide-free VCSEL is demonstrating many advantages in beam pattern, spectral control, and reliability. These lithographic VCSELs offer increased power density from a given aperture size, and enable dense integration of high efficiency and single mode elements that improve beam pattern. In this paper we present results for lithographic VCSELs and describes integration into military systems for very low cost pulsed applications, as well as continuouswave applications in novel sensing applications. The VCSELs are being developed for U.S. Army for soldier weapon engagement simulation training to improve beam pattern and spectral control. Wavelengths in the 904 nm to 990 nm ranges are being developed with the spectral control designed to eliminate unwanted water absorption bands from the data links. Multiple beams and radiation patterns based on highly compact packages are being investigated for improved target sensing and transmission fidelity in free space data links. These novel features based on the new VCSEL sources are also expected to find applications in 3-D imaging, proximity sensing and motion control, as well as single mode sensors such as atomic clocks and high speed data transmission.

Radiation Dose-effects on Cell Cycle, Apoptosis, and Marker Expression of Ataxia Telangiectasia-Heterozygous Human Breast Epithelial Cells

NASA Technical Reports Server (NTRS)

Cruz, A.; Bors, K.; Jansen, H.; Richmond, R.

2003-01-01

Ataxia-telangiectasia (A-T) is a radiation-sensitive genetic condition. AT-heterozygous human mammary epithelial cells (HMEC) were irradiated using a Cs137 source in order to compare cell cycle, apoptosis, and marker expression responses across 3 radiation doses. No differences in cell cycle and apoptosis were found with any of the radiation doses used (30, 60, and 90 rads) compared with the unirradiated control (0 rad). At the same doses, however, differences were found in marker expression, such as keratin 18 (kl8), keratin 14 (k14), insulin-like growth factor I receptor (IGF-IR), and connexin 43 (cx43). This may indicate that radiation sensitivity in the heterozygous state may be initiated through signal transduction responses.

40 CFR 85.1402 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM MOBILE SOURCES Urban Bus Rebuild Requirements § 85.1402 Definitions. The definitions of this... of Mobile Sources—Office of Air and Radiation of the Environmental Protection Agency. Office Director...

Collimator of multiple plates with axially aligned identical random arrays of apertures

NASA Technical Reports Server (NTRS)

Hoover, R. B.; Underwood, J. H. (Inventor)

1973-01-01

A collimator is disclosed for examining the spatial location of distant sources of radiation and for imaging by projection, small, near sources of radiation. The collimator consists of a plurality of plates, all of which are pierced with an identical random array of apertures. The plates are mounted perpendicular to a common axis, with like apertures on consecutive plates axially aligned so as to form radiation channels parallel to the common axis. For near sources, the collimator is interposed between the source and a radiation detector and is translated perpendicular to the common axis so as to project radiation traveling parallel to the common axis incident to the detector. For far sources the collimator is scanned by rotating it in elevation and azimuth with a detector to determine the angular distribution of the radiation from the source.

Laser-plasma accelerator and femtosecond photon sources-based ultrafast radiation chemistry and biophysics

NASA Astrophysics Data System (ADS)

Gauduel, Y. A.

2017-02-01

The initial distribution of energy deposition triggered by the interaction of ionizing radiations (far UV and X rays, electron, proton and accelerated ions) with molecular targets or integrated biological systems is often decisive for the spatio-temporal behavior of radiation effects that take place on several orders of magnitude. This contribution deals with an interdisciplinary approach that concerns cutting-edge advances on primary radiation events, considering the potentialities of innovating strategies based on ultrafast laser science, from femtosecond photon sources to laser-driven relativistic particles acceleration. Recent advances of powerful TW laser sources (~ 1019 Wcm-2) and laser-plasma interactions providing ultrashort relativistic particle beams in the energy domain 2.5-150 MeV open exciting opportunities for the development of high-energy radiation femtochemistry (HERF). Early radiation damages being dependent on the survival probability of secondary electrons and radial distribution of short-lived radicals inside ionization clusters, a thorough knowledge of these processes involves the real-time probing of primary events in the temporal range 10-14-10-11 s. In the framework of a closed synergy between low-energy radiation femtochemistry (LERF) and the emerging domain of HERF, the paper focuses on early phenomena that occur in the prethermal regime of low-energy secondary electrons, considering very short-lived quantum effects in aqueous environments. A high dose-rate delivered by femtosecond electron beam (~ 1011-1013 Gy s-1) can be used to investigate early radiation processes in native ionization tracks, down to 10-12 s and 10-9 m. We explain how this breakthrough favours the innovating development of real-time nanodosimetry in biologically relevant environments and open new perspectives for spatio-temporal radiation biophysics. The emerging domain of HERF would provide guidance for understanding the specific bioeffects of ultrashort particle bunches. This domain represents also a prerequisite for the control of in vitro and in vivo irradiation at ultrahigh dose-rates or the investigation of ultrafast dose-fractionating phenomena.

Wave field synthesis of moving virtual sound sources with complex radiation properties.

PubMed

Ahrens, Jens; Spors, Sascha

2011-11-01

An approach to the synthesis of moving virtual sound sources with complex radiation properties in wave field synthesis is presented. The approach exploits the fact that any stationary sound source of finite spatial extent radiates spherical waves at sufficient distance. The angular dependency of the radiation properties of the source under consideration is reflected by the amplitude and phase distribution on the spherical wave fronts. The sound field emitted by a uniformly moving monopole source is derived and the far-field radiation properties of the complex virtual source under consideration are incorporated in order to derive a closed-form expression for the loudspeaker driving signal. The results are illustrated via numerical simulations of the synthesis of the sound field of a sample moving complex virtual source.

Device and Method of Scintillating Quantum Dots for Radiation Imaging

NASA Technical Reports Server (NTRS)

Burke, Eric R. (Inventor); DeHaven, Stanton L. (Inventor); Williams, Phillip A. (Inventor)

2017-01-01

A radiation imaging device includes a radiation source and a micro structured detector comprising a material defining a surface that faces the radiation source. The material includes a plurality of discreet cavities having openings in the surface. The detector also includes a plurality of quantum dots disclosed in the cavities. The quantum dots are configured to interact with radiation from the radiation source, and to emit visible photons that indicate the presence of radiation. A digital camera and optics may be used to capture images formed by the detector in response to exposure to radiation.

Thermal Image Sensing Model for Robotic Planning and Search.

PubMed

Castro Jiménez, Lídice E; Martínez-García, Edgar A

2016-08-08

This work presents a search planning system for a rolling robot to find a source of infra-red (IR) radiation at an unknown location. Heat emissions are observed by a low-cost home-made IR passive visual sensor. The sensor capability for detection of radiation spectra was experimentally characterized. The sensor data were modeled by an exponential model to estimate the distance as a function of the IR image's intensity, and, a polynomial model to estimate temperature as a function of IR intensities. Both theoretical models are combined to deduce a subtle nonlinear exact solution via distance-temperature. A planning system obtains feed back from the IR camera (position, intensity, and temperature) to lead the robot to find the heat source. The planner is a system of nonlinear equations recursively solved by a Newton-based approach to estimate the IR-source in global coordinates. The planning system assists an autonomous navigation control in order to reach the goal and avoid collisions. Trigonometric partial differential equations were established to control the robot's course towards the heat emission. A sine function produces attractive accelerations toward the IR source. A cosine function produces repulsive accelerations against the obstacles observed by an RGB-D sensor. Simulations and real experiments of complex indoor are presented to illustrate the convenience and efficacy of the proposed approach.

Solid-state radiation-emitting compositions and devices

DOEpatents

Ashley, Carol S.; Brinker, C. Jeffrey; Reed, Scott; Shepodd, Timothy J.; Leonard, Leroy E.; Ellefson, Robert E.; Gill, John T.; Walko, Robert J.; Renschler, Clifford L.

1992-01-01

The invention relates to a composition for the volumetric generation of radiation, wherein a first substance functions as a source of exciting radiation, and a second substance interacts with the exciting radiation to provide a second radiation. The compositions comprise a porous substrate which is loaded with: a source of exciting radiation, a component capable of emitting radiation upon interaction with the exciting radiation, or both. In the composition, a composite is formed from a carrier material and at least one of the source of the exciting radiation or the component which is capable of interacting with the exciting radiation. The composite is then employed for loading a porous substrate, preferably an aerogel substrate.

An improved radiation metric. [for radiation pressure in strong gravitational fields

NASA Technical Reports Server (NTRS)

Noerdlinger, P. D.

1976-01-01

An improved radiation metric is obtained in which light rays make a small nonzero angle with the radius, thus representing a source of finite size. Kaufmann's previous solution is criticized. The stabilization of a scatterer near a source of gravitational field and radiation is slightly enhanced for sources of finite size.

Multichannel Spectrometer of Time Distribution

NASA Astrophysics Data System (ADS)

Akindinova, E. V.; Babenko, A. G.; Vakhtel, V. M.; Evseev, N. A.; Rabotkin, V. A.; Kharitonova, D. D.

2015-06-01

For research and control of characteristics of radiation fluxes, radioactive sources in particular, for example, in paper [1], a spectrometer and methods of data measurement and processing based on the multichannel counter of time intervals of accident events appearance (impulses of particle detector) MC-2A (SPC "ASPECT") were created. The spectrometer has four independent channels of registration of time intervals of impulses appearance and correspondent amplitude and spectrometric channels for control along the energy spectra of the operation stationarity of paths of each of the channels from the detector to the amplifier. The registration of alpha-radiation is carried out by the semiconductor detectors with energy resolution of 16-30 keV. Using a spectrometer there have been taken measurements of oscillations of alpha-radiation 239-Pu flux intensity with a subsequent autocorrelative statistical analysis of the time series of readings.

Synchrotron Radiation Research--An Overview.

ERIC Educational Resources Information Center

Bienenstock, Arthur; Winick, Herman

1983-01-01

Discusses expanding user community seeking access to synchrotron radiation sources, properties/sources of synchrotron radiation, permanent-magnet technology and its impact on synchrotron radiation research, factors limiting power, the density of synchrotron radiation, and research results illustrating benefit of higher flux and brightness. Also…

Light Source

NASA Technical Reports Server (NTRS)

1993-01-01

Research on food growth for long duration spacecraft has resulted in a light source for growing plants indoors known as Qbeam, a solid state light source consisting of a control unit and lamp. The light source, manufactured by Quantum Devices, Inc., is not very hot, although it generates high intensity radiation. When Ron Ignatius, an industrial partner of WCSAR, realized that terrestrial plant research lighting was not energy efficient enough for space use, he and WCSAR began to experiment with light emitting diodes. A line of LED products was developed, and QDI was formed to market the technology. An LED-based cancer treatment device is currently under development.

[Applications of electromagnetic radiation in medicine].

PubMed

Miłowska, Katarzyna; Grabowska, Katarzyna; Gabryelak, Teresa

2014-05-08

Recent decades have been devoted to the intense search for the response to questions related to the impact of radiation on the human body. Due to the growing fashion for a healthy lifestyle, increasing numbers of works about the alleged dangers of electromagnetic waves and diseases that they cause appeared. However, the discoveries of 20th century, and knowledge of the properties of electromagnetic radiation have allowed to broaden the horizons of the use of artificial sources of radiation in many fields of science and especially in medicine. The aim of this paper is to show that although excessive radiation or high doses are dangerous to the human body, its careful and controlled use, does not pose a threat, and it is often necessary in therapy. The possibility of using ionizing radiation in radiotherapy, isotope diagnostics or medical imaging, and non-ionizing radiation in the treatment for dermatological disorders and cancers will be presented. The unique properties of synchrotron radiation result in using it on a large scale in the diagnosis of pathological states by imaging methods.

A decade of changes in radiation protection.

PubMed

Moulder, J E

1992-04-01

Although radiation protection standards have changed remarkably little over the past decade, there have been changes in our understanding of radiation hazards that may affect the practice of radiation medicine over the next decade. With recognition of indoor radon exposure has come a new focus for public health concerns, because it is now clear that radon rather than medical exposure is the largest controllable source of radiation exposure to the general public. Continued follow-up of irradiated populations has led to an increase in our estimate of the cancer risk for high-dose exposures; this increased risk estimate is, in turn, leading to decreases in radiation exposure limits. Although our concern about the carcinogenic risk for radiation exposure has increased, our concern about genetic consequences has decreased, because no genetic effects have yet been observed in the offspring of atomic bomb survivors. Studies of atomic bomb survivors have also led to a change in the focus of concern over prenatal radiation exposure; the principle risk now appears to be mental retardation rather than childhood cancer.

Uncertainty in Arctic climate projections traced to variability of downwelling longwave radiation

NASA Astrophysics Data System (ADS)

Krikken, Folmer; Bintanja, Richard; Hazeleger, WIlco; van Heerwaarden, Chiel

2017-04-01

The Arctic region has warmed rapidly over the last decades, and this warming is projected to increase. The uncertainty in these projections, i.e. intermodel spread, is however very large and a clear understanding of the sources behind the spread is so far still lacking. Here we use 31 state-of-the-art global climate models to show that variability of May downwelling radiation (DLR) in the models' control climate, primarily located at the land surrounding the Arctic ocean, explains 2/3 of the intermodel spread in projected Arctic warming under the RPC85 scenario. This variability is related to the combined radiative effect of the cloud radiative forcing (CRF) and the albedo response due to snowfall, which varies strongly between the models in these regions. This mechanism dampens or enhances yearly variability of DLR in the control climate but also dampens or enhances the climate response of DLR, sea ice cover and near surface temperature.

Applications of Coherent Radiation from Electrons traversing Crystals

NASA Astrophysics Data System (ADS)

Überall, H.

2000-04-01

Historically, the first types of coherent radiation from electrons traversing crystals studied were coherent bremsstrahlung (CB: Dyson and Überall 1955; Überall 1956, 1962) and channeling radiation (CR: Kumakhov, 1976) which produce quasimonochromatic X-rays and γ-rays, as well as parametric X-rays (Baryshevsky and Feranchuk, 1983). Related non-crystal sources are transition radiation and synchrotron radiation. We here present a comparison of radiation types from these sources, and we discuss a series of their possible applications, namely (a) CR: X-ray lithography, angiography, structure analysis of macromolecules, and trace element analysis, and (b) for CB: Radiography, use as a neutron source, elemental analysis, radiation therapy, and radioisotope production for commercial or medical use. CR and CB are very intense sources, needing only low-energy, moderately-priced electron linacs for their generation, hence competing with (or surpassing) more conventional X-ray sources intensity-wise and from a cost standpoint.

Method and apparatus for shadow aperture backscatter radiography (SABR) system and protocol

NASA Technical Reports Server (NTRS)

Shedlock, Daniel (Inventor); Jacobs, Alan M. (Inventor); Jacobs, Sharon Auerback (Inventor); Dugan, Edward (Inventor)

2010-01-01

A shadow aperture backscatter radiography (SABR) system includes at least one penetrating radiation source for providing a penetrating radiation field, and at least one partially transmissive radiation detector, wherein the partially transmissive radiation detector is interposed between an object region to be interrogated and the radiation source. The partially transmissive radiation detector transmits a portion of the illumination radiation field. A shadow aperture having a plurality of radiation attenuating regions having apertures therebetween is disposed between the radiation source and the detector. The apertures provide illumination regions for the illumination radiation field to reach the object region, wherein backscattered radiation from the object is detected and generates an image by the detector in regions of the detector that are shadowed by the radiation attenuation regions.

A multimode terahertz-Orotron with the special Smith–Purcell radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Weihao, E-mail: liuwhao@ustc.edu.cn; Lu, Yalin; Wang, Lin

2016-05-02

We proposed and investigated a terahertz Orotron, which is based on the recently revealed special Smith–Purcell radiation. It overcomes the main obstacles of the traditional Orotron in the terahertz region—unreachable high starting-current-density and low radiation power. With the experimentally available electron beam and facilities, its average output power can reach hundreds of milliwatts and even several watts in terahertz region, which is many orders of magnitude higher than that of the traditional Orotron. Additionally, it can be controlled to operate in ether the first or the second order mode, and the radiation frequency can extend from 0.1 THz to 1more » THz. These remarkable advantages make it a promising terahertz source for practical applications.« less

Device for calibrating a radiation detector system

DOEpatents

McFee, M.C.; Kirkham, T.J.; Johnson, T.H.

1994-12-27

A device is disclosed for testing a radiation detector system that includes at least two arrays of radiation detectors that are movable with respect to each other. The device includes a ''shield plate'' or shell, and an opposing ''source plate'' containing a source of ionizing radiation. Guides are attached to the outer surface of the shell for engaging the forward ends of the detectors, thereby reproducibly positioning the detectors with respect to the source and with respect to each other, thereby ensuring that a predetermined portion of the radiation emitted by the source passes through the shell and reaches the detectors. The shell is made of an hydrogenous material having approximately the same radiological attenuation characteristics as composite human tissue. The source represents a human organ such as the lungs, heart, kidneys, liver, spleen, pancreas, thyroid, testes, prostate, or ovaries. The source includes a source of ionizing radiation having a long half-life and an activity that is within the range typically searched for in human subjects. 3 figures.

Device for calibrating a radiation detector system

DOEpatents

Mc Fee, Matthew C.; Kirkham, Tim J.; Johnson, Tippi H.

1994-01-01

A device for testing a radiation detector system that includes at least two arrays of radiation detectors that are movable with respect to each other. The device includes a "shield plate" or shell, and an opposing "source plate" containing a source of ionizing radiation. Guides are attached to the outer surface of the shell for engaging the forward ends of the detectors, thereby reproducibly positioning the detectors with respect to the source and with respect to each other, thereby ensuring that a predetermined portion of the radiation emitted by the source passes through the shell and reaches the detectors. The shell is made of an hydrogenous material having approximately the same radiological attenuation characteristics as composite human tissue. The source represents a human organ such as the lungs, heart, kidneys, heart, liver, spleen, pancreas, thyroid, testes, prostate, or ovaries. The source includes a source of ionizing radiation having a long half-life and an activity that is within the range typically searched for in human subjects.

A compact tunable polarized X-ray source based on laser-plasma helical undulators

PubMed Central

Luo, J.; Chen, M.; Zeng, M.; Vieira, J.; Yu, L. L.; Weng, S. M.; Silva, L. O.; Jaroszynski, D. A.; Sheng, Z. M.; Zhang, J.

2016-01-01

Laser wakefield accelerators have great potential as the basis for next generation compact radiation sources because of their extremely high accelerating gradients. However, X-ray radiation from such devices still lacks tunability, especially of the intensity and polarization distributions. Here we propose a tunable polarized radiation source based on a helical plasma undulator in a plasma channel guided wakefield accelerator. When a laser pulse is initially incident with a skew angle relative to the channel axis, the laser and accelerated electrons experience collective spiral motions, which leads to elliptically polarized synchrotron-like radiation with flexible tunability on radiation intensity, spectra and polarization. We demonstrate that a radiation source with millimeter size and peak brilliance of 2 × 1019 photons/s/mm2/mrad2/0.1% bandwidth can be made with moderate laser and electron beam parameters. This brilliance is comparable with third generation synchrotron radiation facilities running at similar photon energies, suggesting that laser plasma based radiation sources are promising for advanced applications. PMID:27377126

3-dimensional imaging system using crystal diffraction lenses

DOEpatents

Smither, R.K.

1999-02-09

A device for imaging a plurality of sources of x-ray and gamma-ray radiation is provided. Diffracting crystals are used for focusing the radiation and directing the radiation to a detector which is used for analyzing their addition to collect data as to the location of the source of radiation. A computer is used for converting the data to an image. The invention also provides for a method for imaging x-ray and gamma radiation by supplying a plurality of sources of radiation; focusing the radiation onto a detector; analyzing the focused radiation to collect data as to the type and location of the radiation; and producing an image using the data. 18 figs.

78 FR 21567 - Installation of Radiation Alarms for Rooms Housing Neutron Sources

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-11

... [Docket No. PRM-73-15; NRC-2011-0251] Installation of Radiation Alarms for Rooms Housing Neutron Sources... amend its regulations to require the installation of radiation alarms for rooms housing neutron sources... alarms for rooms housing neutron sources. The petitioner stated that the use of alarms can be effective...

WORK SAFETY CONDITIONS WITH CLOSED RADIATION SOURCES (in Polish)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brosziewicz, R.

1963-01-01

A discussion is presented of principles of radiological protection observed in the Radiation Chemistry Dept. of the Nuclear Research Inst., during operation of large sources of ionizing radiation. It has been revealed that a properly designed servicing system of these sources ensures full protection of personnel even with not fully protected sources. (auth)

Induction of Cell Death through Alteration of Oxidants and Antioxidants in Epithelial Cells Exposed to High Energy Protons

NASA Technical Reports Server (NTRS)

Ramesh, Govindarajan; Wu, Honglu

2012-01-01

Radiation affects several cellular and molecular processes including double strand breakage, modifications of sugar moieties and bases. In outer space, protons are the primary radiation source which poses a range of potential health risks to astronauts. On the other hand, the use of proton radiation for tumor radiation therapy is increasing as it largely spares healthy tissues while killing tumor tissues. Although radiation related research has been conducted extensively, the molecular toxicology and cellular mechanisms affected by proton radiation remain poorly understood. Therefore, in the present study, we irradiated rat epithelial cells (LE) with different doses of protons and investigated their effects on cell proliferation and cell death. Our data showed an inhibition of cell proliferation in proton irradiated cells with a significant dose dependent activation and repression of reactive oxygen species (ROS) and antioxidants, glutathione and superoxide dismutase respectively as compared to control cells. In addition, apoptotic related genes such as caspase-3 and -8 activities were induced in a dose dependent manner with corresponding increased levels of DNA fragmentation in proton irradiated cells than control cells. Together, our results show that proton radiation alters oxidant and antioxidant levels in the cells to activate apoptotic pathway for cell death.

The non-radiating component of the field generated by a finite monochromatic scalar source distribution

NASA Astrophysics Data System (ADS)

Hoenders, Bernhard J.; Ferwerda, Hedzer A.

1998-09-01

We separate the field generated by a spherically symmetric bounded scalar monochromatic source into a radiative and non-radiative part. The non-radiative part is obtained by projecting the total field on the space spanned by the non-radiating inhomogeneous modes, i.e. the modes which satisfy the inhomogeneous wave equation. Using residue techniques, introduced by Cauchy, we obtain an explicit analytical expression for the non-radiating component. We also identify the part of the source distribution which corresponds to this non-radiating part. The analysis is based on the scalar wave equation.

Landscape fires dominate terrestrial natural aerosol - climate feedbacks

NASA Astrophysics Data System (ADS)

Scott, C.; Arnold, S.; Monks, S. A.; Asmi, A.; Paasonen, P.; Spracklen, D. V.

2017-12-01

The terrestrial biosphere is an important source of natural aerosol including landscape fire emissions and secondary organic aerosol (SOA) formed from biogenic volatile organic compounds (BVOCs). Atmospheric aerosol alters the Earth's climate by absorbing and scattering radiation (direct radiative effect; DRE) and by perturbing the properties of clouds (aerosol indirect effect; AIE). Natural aerosol sources are strongly controlled by, and can influence, climate; giving rise to potential natural aerosol-climate feedbacks. Earth System Models (ESMs) include a description of some of these natural aerosol-climate feedbacks, predicting substantial changes in natural aerosol over the coming century with associated radiative perturbations. Despite this, the sensitivity of natural aerosols simulated by ESMs to changes in climate or emissions has not been robustly tested against observations. Here we combine long-term observations of aerosol number and a global aerosol microphysics model to assess terrestrial natural aerosol-climate feedbacks. We find a strong positive relationship between the summertime anomaly in observed concentration of particles greater than 100 nm diameter and the anomaly in local air temperature. This relationship is reproduced by the model and driven by variability in dynamics and meteorology, as well as natural sources of aerosol. We use an offline radiative transfer model to determine radiative effects due to changes in two natural aerosol sources: landscape fire and biogenic SOA. We find that interannual variability in the simulated global natural aerosol radiative effect (RE) is negatively related to the global temperature anomaly. The magnitude of global aerosol-climate feedback (sum of DRE and AIE) is estimated to be -0.15 Wm-2 K-1 for landscape fire aerosol and -0.06 Wm-2 K-1 for biogenic SOA. These feedbacks are comparable in magnitude, but opposite in sign to the snow albedo feedback, highlighting the need for natural aerosol feedbacks to be included in climate simulations.

[The spectra of a laser-produced plasma source with CO2, O2 and CF4 liquid aerosol spray target].

PubMed

Ni, Qi-Liang; Chen, Bo

2008-11-01

A laser-produced plasma (LPP) source with liquid aerosol spray target and nanosecond laser was developed, based on both soft X-ray radiation metrology and extreme ultraviolet projection lithography (EUVL). The LPP source is composed of a stainless steel solenoid valve whose temperature can be continuously controlled, a Nd : YAG laser with pulse width, working wavelength and pulse energy being 7 ns, 1.064 microm and 1J respectively, and a pulse generator which can synchronously control the valve and the laser. A standard General Valve Corporation series 99 stainless steel solenoid valve with copper gasket seals and a Kel-F poppet are used in order to minimize leakage and poppet deformation during high-pressure cryogenic operation. A close fitting copper cooling jacket surrounds the valve body. The jacket clamps a copper coolant carrying tube 3 mm in diameter, which is fed by an automatically pressurized liquid nitrogen-filled dewar. The valve temperature can be controlled between 77 and 473 K. For sufficiently high backing pressure and low temperature, the valve reservoir gas can undergo a gas-to-liquid phase transition. Upon valve pulsing, the liquid is ejected into a vacuum and breaks up into droplets, which is called liquid aerosol spray target. For the above-mentioned LPP source, firstly, by the use of Cowan program on the basis of non-relativistic quantum mechanics, the authors computed the radiative transition wavelengths and probabilities in soft X-ray region for O4+, O5+, O6+, O7+, F5+, F6+ and F7+ ions which were correspondingly produced from the interaction of the 10(11)-10(12) W x cm(-2) power laser with liquid O2, CO2 and CF4 aerosol spray targets. Secondly, the authors measured the spectra of liquid O2, CO2 and CF4 aerosol spray target LPP sources in the 6-20 nm band for the 8 x 10(11) W x cm(-2) laser irradiance. The measured results were compared with the Cowan calculated results ones, and the radiative transition wavelength and probability for the measured spectral lines were obtained.

Comparing the Hematopoetic Syndrome Time Course in the NHP Animal Model to Radiation Accident Cases From the Database Search.

PubMed

Graessle, Dieter H; Dörr, Harald; Bennett, Alexander; Shapiro, Alla; Farese, Ann M; MacVittie, Thomas J; Meineke, Viktor

2015-11-01

Since controlled clinical studies on drug administration for the acute radiation syndrome are lacking, clinical data of human radiation accident victims as well as experimental animal models are the main sources of information. This leads to the question of how to compare and link clinical observations collected after human radiation accidents with experimental observations in non-human primate (NHP) models. Using the example of granulocyte counts in the peripheral blood following radiation exposure, approaches for adaptation between NHP and patient databases on data comparison and transformation are introduced. As a substitute for studying the effects of administration of granulocyte-colony stimulating factor (G-CSF) in human clinical trials, the method of mathematical modeling is suggested using the example of G-CSF administration to NHP after total body irradiation.

10 CFR 36.23 - Access control.

Code of Federal Regulations, 2010 CFR

2010-01-01

... REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR IRRADIATORS Design and Performance... irradiator must have a door or other physical barrier to prevent inadvertent entry of personnel if the sources are not in the shielded position. Product conveyor systems may serve as barriers as long as they...

Response of humpback whales (Megaptera novaeangliae) to ramp-up of a small experimental air gun array.

PubMed

Dunlop, Rebecca A; Noad, Michael J; McCauley, Robert D; Kniest, Eric; Slade, Robert; Paton, David; Cato, Douglas H

2016-02-15

'Ramp-up', or 'soft start', is a mitigation measure used in seismic surveys and involves increasing the radiated sound level over 20-40 min. This study compared the behavioural response in migrating humpback whales to the first stages of ramp-up with the response to a 'constant' source, 'controls' (in which the array was towed but not operated) with groups in the absence of the source vessel used as the 'baseline'. Although the behavioural response, in most groups, resulted in an increase in distance from the source (potential avoidance), there was no evidence that either 'ramp-up' or the constant source at a higher level was superior for triggering whales to move away from the source vessel. 'Control' groups also responded suggesting the presence of the source vessel had some effect. However, the majority of groups appeared to avoid the source vessel at distances greater than the radius of most mitigation zones. Copyright © 2016 Elsevier Ltd. All rights reserved.

A Design of a Modular GPHS-Stirling Power System for a Lunar Habitation Module

NASA Technical Reports Server (NTRS)

Schmitz, Paul C.; Penswick, L. Barry; Shaltens, Richard K.

2005-01-01

Lunar habitation modules need electricity and potentially heat to operate. Because of the low amounts of radiation emitted by General Purpose Heat Source (GPHS) modules, power plants incorporating these as heat sources could be placed in close proximity to habitation modules. A design concept is discussed for a high efficiency power plant based on a GPHS assembly integrated with a Stirling convertor. This system could provide both electrical power and heat, if required, for a lunar habitation module. The conceptual GPHS/Stirling system is modular in nature and made up of a basic 5.5 KWe Stirling convertor/GPHS module assembly, convertor controller/PMAD electronics, waste heat radiators, and associated thermal insulation. For the specific lunar application under investigation eight modules are employed to deliver 40 KWe to the habitation module. This design looks at three levels of Stirling convertor technology and addresses the issues of integrating the Stirling convertors with the GPHS heat sources assembly using proven technology whenever possible. In addition, issues related to the high-temperature heat transport system, power management, convertor control, vibration isolation, and potential system packaging configurations to ensure safe operation during all phases of deployment will be discussed.

Noise suppression of a dipole source by tensioned membrane with side-branch cavities

PubMed Central

Liu, Y.; Choy, Y. S.; Huang, L.; Cheng, L.

2012-01-01

Reducing the ducted-fan noise at the low frequency range remains a big technical challenge. This study presents a passive approach to directly suppress the dipole sound radiation from an axial-flow fan housed by a tensioned membrane with cavity backing. The method aims at achieving control of low frequency noise with an appreciable bandwidth. The use of the membrane not only eliminates the aerodynamic loss of flow, but also provides flexibility in controlling the range of the stopband with high insertion loss by varying its tension and mass. A three-dimensional model is presented which allows the performance of the proposed device to be explored analytically. With the proper design, this device can achieve a noise reduction of 5 dB higher than the empty expansion cavity recently proposed by Huang et al. [J. Acoust. Soc. Am. 128, 152–163 (2010)]. Through the detailed modal analysis, even in vacuo modes of the membrane vibration are found to play an important role in the suppression of sound radiation from the dipole source. Experimental validation is conducted with a loudspeaker as the dipole source and good agreement between the predicted and measured insertion loss is achieved. PMID:22978868

Gamma greenhouse: A chronic facility for crops improvement and agrobiotechnology

NASA Astrophysics Data System (ADS)

Azhar, M.; Ahsanulkhaliqin, A. W.

2014-02-01

Gamma irradiation is one of the most common procedures in plant mutagenesis and agrobiotechnology activities. The procedures consist of chronic and acute gamma radiation. Generally, 60Co and 137Cs are gamma radiation sources for radiation processing with relatively high energy (half-life 5.27 years for 60Co and 30.1 years for 137Cs). The energy associated with gamma radiation is high enough to break the molecular bonds and ionize atoms without affecting structure of the atomic nucleus (avoiding induction of radioactivity). The Gamma Green House (GGH) is the only chronic irradiation facility in Malaysia, located at Malaysian Nuclear Agency (Nuclear Malaysia). GGH is used for induction of mutation in plants and other biological samples at low dose radiation over period of time depending on the nature and sensitivity of the plant species. The GGH consist of circular green house with 30 meters radius, control room and irradiator with interlock system. The irradiator produces low dose gamma radiation derived from Caesium-137 radioactive source. The biological samples can be exposed to low dose radiation in days, weeks, months or years. The current irradiation rate for GGH is 2.67 Gy/hr at 1 meter from the source. Chronic gamma irradiation produces a wider mutation spectrum and useful for minimizing radiation damages towards obtaining new improved traits for research and commercial values. The prospect of the gamma greenhouse is its uses in research, educations and services on induced mutation techniques for the improvement of plant varieties and microbes. In generating awareness and attract users to the facility, Nuclear Malaysia provides wide range of irradiation services for plant species and mutagenesis consultancies to academicians, students scientists, and plant breeders, from local universities, other research institutes, and growers. Charges for irradiation and consultancy services are at nominal rates. The utilization activities of the gamma greenhouse mainly cover Research and Development, Research Collaboration, Exchange of Information, Irradiation Services, Training Programs, Education, Exchange of Scientists and Seminars/ Conferences.

Experimental verification of isotropic radiation from a coherent dipole source via electric-field-driven LC resonator metamaterials.

PubMed

Tichit, Paul-Henri; Burokur, Shah Nawaz; Qiu, Cheng-Wei; de Lustrac, André

2013-09-27

It has long been conjectured that isotropic radiation by a simple coherent source is impossible due to changes in polarization. Though hypothetical, the isotropic source is usually taken as the reference for determining a radiator's gain and directivity. Here, we demonstrate both theoretically and experimentally that an isotropic radiator can be made of a simple and finite source surrounded by electric-field-driven LC resonator metamaterials designed by space manipulation. As a proof-of-concept demonstration, we show the first isotropic source with omnidirectional radiation from a dipole source (applicable to all distributed sources), which can open up several possibilities in axion electrodynamics, optical illusion, novel transformation-optic devices, wireless communication, and antenna engineering. Owing to the electric- field-driven LC resonator realization scheme, this principle can be readily applied to higher frequency regimes where magnetism is usually not present.

Delayed Effects of Acute Radiation Exposure in a Murine Model of the H-ARS: Multiple-Organ Injury Consequent to <10 Gy Total Body Irradiation.

PubMed

Unthank, Joseph L; Miller, Steven J; Quickery, Ariel K; Ferguson, Ethan L; Wang, Meijing; Sampson, Carol H; Chua, Hui Lin; DiStasi, Matthew R; Feng, Hailin; Fisher, Alexa; Katz, Barry P; Plett, P Artur; Sandusky, George E; Sellamuthu, Rajendran; Vemula, Sasidhar; Cohen, Eric P; MacVittie, Thomas J; Orschell, Christie M

2015-11-01

The threat of radiation exposure from warfare or radiation accidents raises the need for appropriate animal models to study the acute and chronic effects of high dose rate radiation exposure. The goal of this study was to assess the late development of fibrosis in multiple organs (kidney, heart, and lung) in survivors of the C57BL/6 mouse model of the hematopoietic-acute radiation syndrome (H-ARS). Separate groups of mice for histological and functional studies were exposed to a single uniform total body dose between 8.53 and 8.72 Gy of gamma radiation from a Cs radiation source and studied 1-21 mo later. Blood urea nitrogen levels were elevated significantly in the irradiated mice at 9 and 21 mo (from ∼22 to 34 ± 3.8 and 69 ± 6.0 mg dL, p < 0.01 vs. non-irradiated controls) and correlated with glomerosclerosis (29 ± 1.8% vs. 64 ± 9.7% of total glomeruli, p < 0.01 vs. non-irradiated controls). Glomerular tubularization and hypertrophy and tubular atrophy were also observed at 21 mo post-total body irradiation (TBI). An increase in interstitial, perivascular, pericardial and peribronchial fibrosis/collagen deposition was observed from ∼9-21 mo post-TBI in kidney, heart, and lung of irradiated mice relative to age-matched controls. Echocardiography suggested decreased ventricular volumes with a compensatory increase in the left ventricular ejection fraction. The results indicate that significant delayed effects of acute radiation exposure occur in kidney, heart, and lung in survivors of the murine H-ARS TBI model, which mirrors pathology detected in larger species and humans at higher radiation doses focused on specific organs.

Generation of tunable radially polarized array beams by controllable coherence

NASA Astrophysics Data System (ADS)

Wang, Jing; Zhang, Jipeng; Zhu, Shijun; Li, Zhenhua

2017-05-01

In this paper, a new method for converting a single radial polarization beam into an arbitrary radially polarized array (RPA) beam such as a radial or rectangular symmetry array in the focal plane by modulating a periodic correlation structure is introduced. The realizability conditions for such source and the beam condition for radiation generated by such source are derived. It is illustrated that both the amplitude and the polarization are controllable by means of initial correlation structure and coherence parameter. Furthermore, by designing the source correlation structure, a tunable NUST-shaped RPA beam is demonstrated, which can find widespread applications in micro-nano engineering. Such a method for generation of arbitrary vector array beams is useful in beam shaping and optical tweezers.

Data-based Considerations in Portal Radiation Monitoring of Cargo Vehicles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weier, Dennis R.; O'Brien, Robert F.; Ely, James H.

2004-07-01

Radiation portal monitoring of cargo vehicles often includes a configuration of four-panel monitors that record gamma and neutron counts from vehicles transporting cargo. As vehicles pass the portal monitors, they generate a count profile over time that can be compared to the average panel background counts obtained just prior to the time the vehicle entered the area of the monitors. Pacific Northwest National Laboratory has accumulated considerable data regarding such background radiation and vehicle profiles from portal installations, as well as in experimental settings using known sources and cargos. Several considerations have a bearing on how alarm thresholds are setmore » in order to maintain sensitivity to radioactive sources while also controlling to a manageable level the rate of false or nuisance alarms. False alarms are statistical anomalies while nuisance alarms occur due to the presence of naturally occurring radioactive material (NORM) in cargo, for example, kitty litter. Considerations to be discussed include: • Background radiation suppression due to the shadow shielding from the vehicle. • The impact of the relative placement of the four panels on alarm decision criteria. • Use of plastic scintillators to separate gamma counts into energy windows. • The utility of using ratio criteria for the energy window counts rather than simply using total window counts. • Detection likelihood for these various decision criteria based on computer simulated injections of sources into vehicle profiles.« less

Study of the thermal distribution in vocal cords irradiated by an optical source for the treatment of voice disabilities

NASA Astrophysics Data System (ADS)

Arce-Diego, José L.; Fanjul-Vélez, Félix; Borragán-Torre, Alfonso

2006-02-01

Vocal cords disorders constitute an important problem for people suffering from them. Particularly the reduction of mucosal wave movement is not appropriately treated by conventional therapies, like drugs administration or surgery. In this work, an alternative therapy, consisting in controlled temperature increases by means of optical sources is proposed. The distribution of heat inside vocal cords when an optical source illuminates them is studied. Optical and thermal properties of tissue are discussed, as a basis for the appropriate knowledge of its behaviour. Propagation of light is shown using the Radiation Transfer Theory (RTT) and a numerical Monte Carlo model. A thermal transfer model, that uses the results of the propagation of radiation, determines the distribution of temperature in the tissue. Two widely used lasers are considered, Nd:YAG (1064 nm) and KTP (532 nm). Adequate amounts of radiation, resulting in temperature rise, must be achieved in order to avoid damage in vocal cords and so to assure an improvement in the vocal functions of the patient. The limits in temperature should be considered with a combined temperature-time and Arrhenius analysis.

Method for measuring integrated sensitivity of solar cells and multielement photoconverters using an X-Y scanner

NASA Astrophysics Data System (ADS)

Naumov, V. V.; Grebenshchikov, O. A.; Zalesskii, V. B.

2006-09-01

We describe a method for automated measurement of the integrated sensitivity of solar cells (SCs) and multielement photoconverters (MPCs) using an experimental apparatus including a Pentium III personal computer (PC), an HP-34401A digital multimeter (DM), a stabilized radiation source (SRS), a controllable focusing system, an X-Y positioning device based on CD-RW optical disk storage devices. The method provides high accuracy in measuring the size of photosensitive areas of the solar cells and multielement photoconverters and inhomogeneities in their active regions, which makes it possible to correct the production process in the development stage and during fabrication of test prototypes for the solar cells and multielement photoconverters. The radiation power from the stabilized radiation source was ≤1 W; the ranges of the scanning steps along the X, Y coordinates were 10 100 µm, the range of the transverse cross sectional diameters of the focused radiation beam was 10 100 µm, the measurable photocurrents were 10-9 A to 2 A; scanning rate along the X, Y coordinates, ≤100 mm/sec; relative mean-square error (RMSE) for measurement of the integrated sensitivity of the solar cells, 0.2 ≤ γS int ≤ 0.9% in the ranges of measurable photocurrents 1 mA ≤ Iph ≤ 750 mA and areas 0.1 ≤ A ≤ 25 cm2 for number of measurements equal to ≤ 2· 105; instability of the radiation power (luminosity) ≤ 0.08% for 1 h or ≤ 0.4% for 8 h continuous operation; stabilized power range for the stabilized radiation source, 10-2 102 W. The software was written in Delphi 7.0.

Control of jet noise

NASA Technical Reports Server (NTRS)

Schreck, Stefan

1993-01-01

This reports describes experiments conducted at the High-Speed Jet Facility at the University of Southern California on supersonic jets. The goal of the study was to develop methods for controlling the noise emitted from supersonic jets by passive and/or active means. Work by Seiner et al (1991) indicates that eddy Mach wave radiation is the dominant noise source in a heated high speed jet. Eddy Mach radiation is caused by turbulent eddies traveling at supersonic speed in the shear layer of the jet. The convection velocity of the eddies decays with increasing distance from the nozzle exit due to the mixing of the jet stream with the ambient fluid. Once the convection speed reaches subsonic velocities, eddy Mach wave radiation ceases. To control noise, a rapid decay of the convection velocity is desired. This may be accomplished by enhanced mixing in the jet. In this study, small aspect ratio rectangular jet nozzles were tested. A flapping mode was noticed in the jets. By amplifying screech components of the jets and destabilizing the jet columns with a collar device, the flapping mode was excited. The result was a rapid decay of the jet velocity. A reduction in eddy Mach radiation in rectangular supersonic jets may be achieved with this device.

Non-solar ultraviolet radiation and the risk of basal and squamous cell skin cancer.

PubMed Central

Bajdik, C. D.; Gallagher, R. P.; Astrakianakis, G.; Hill, G. B.; Fincham, S.; McLean, D. I.

1996-01-01

A case-control study of non-melanocytic skin cancer was conducted among men in the province of Alberta, Canada. Two hundred and twenty-six cases of basal cell carcinoma (BCC), 180 cases of squamous cell carcinoma (SCC) and 406 age-matched controls provided information concerning skin pigmentation, occupational history, recreational activity, exposure to sunlight and sources of non-solar ultraviolet radiation (NSUVR) and other potential risk factors. Our analyses show no evidence of elevated risk for BCC or SCC among subjects exposed to various types of NSUVR. This is in opposition to studies of melanoma that have shown elevated risks for exposure to fluorescent lighting, sunlamps and sunbeds. PMID:8664139

A Pilot Examination of the Methods Used to Counteract Insider Threat Security Risks Associated with the Use of Radioactive Materials in the Research and Clinical Setting.

PubMed

Tsenov, B G; Emery, R J; Whitehead, L W; Gonzalez, J Reingle; Gemeinhardt, G L

2018-03-01

While many organizations maintain multiple layers of security control methodologies to prevent outsiders from gaining unauthorized access, persons such as employees or contractors who have been granted legitimate access can represent an "insider threat" risk. Interestingly, some of the most notable radiological events involving the purposeful contamination or exposure of individuals appear to have been perpetrated by insiders. In the academic and medical settings, radiation safety professionals focus their security efforts on (1) ensuring controls are in place to prevent unauthorized access or removal of sources, and (2) increasing security controls for the unescorted accessing of large sources of radioactivity (known as "quantities of concern"). But these controls may not completely address the threat insiders represent when radioactive materials below these quantities are present. The goal of this research project was to characterize the methodologies currently employed to counteract the insider security threat for the misuse or purposeful divergence of radioactive materials used in the academic and medical settings. A web-based survey was used to assess how practicing radiation safety professionals in academic and medical settings anticipate, evaluate, and control insider threat security risks within their institutions. While all respondents indicated that radioactive sources are being used in amounts below quantities of concern, only 6 % consider insider threat security issues as part of the protocol review for the use of general radioactive materials. The results of this survey identify several opportunities for improvement for institutions to address security gaps.

Directional radiation detectors

DOEpatents

Dowell, Jonathan L.

2017-09-12

Directional radiation detectors and systems, methods, and computer-readable media for using directional radiation detectors to locate a radiation source are provided herein. A directional radiation detector includes a radiation sensor. A radiation attenuator partially surrounds the radiation sensor and defines an aperture through which incident radiation is received by the radiation sensor. The aperture is positioned such that when incident radiation is received directly through the aperture and by the radiation sensor, a source of the incident radiation is located within a solid angle defined by the aperture. The radiation sensor senses at least one of alpha particles, beta particles, gamma particles, or neutrons.

Transport, charge exchange and loss of energetic heavy ions in the earth's radiation belts - Applicability and limitations of theory

NASA Technical Reports Server (NTRS)

Spjeldvik, W. N.

1981-01-01

Computer simulations of processes which control the relative abundances of ions in the trapping regions of geospace are compared with observations from discriminating ion detectors. Energy losses due to Coulomb collisions between ions and exospheric neutrals are considered, along with charge exchange losses and internal charge exchanges. The time evolution of energetic ion fluxes of equatorially mirroring ions under radial diffusion is modelled to include geomagnetic and geoelectric fluctutations. Limits to the validity of diffusion transport theory are discussed, and the simulation is noted to contain provisions for six ionic charge states and the source effect on the radiation belt oxygen ion distributions. Comparisons are made with ion flux data gathered on Explorer 45 and ISEE-1 spacecraft and results indicate that internal charge exchanges cause the radiation belt ion charge state to be independent of source charge rate characteristics, and relative charge state distribution is independent of the radially diffusive transport rate below the charge state redistribution zone.

A system for protecting the environment from ionising radiation: selecting reference fauna and flora, and the possible dose models and environmental geometries that could be applied to them.

PubMed

Pentreath, R J; Woodhead, D S

2001-09-28

In order to demonstrate, explicitly, that the environment can be protected with respect to controlled sources of ionising radiation, it is essential to have a systematic framework within which dosimetry models for fauna and flora can be used. And because of the practical limitations on what could reasonably be modelled and the amount of information that could reasonably be obtained, it is also necessary to limit the application of such models to a 'set' of fauna and flora within a reference' context. This paper, therefore, outlines the factors that will need to be considered to select such 'reference' fauna and flora, and describes some of the factors and constraints necessary to develop the associated dosimetry models. It also describes some of the most basic environmental geometrics within which the dose models could be set in order to make comparisons amongst different radiation sources.

Multiwavelength pyrometer for gray and non-gray surfaces in the presence of interfering radiation

NASA Technical Reports Server (NTRS)

Ng, Daniel L. P. (Inventor)

1994-01-01

A method and apparatus for detecting the temperature of gray and non-gray bodies in the presence of interfering radiation are presented. A gray body has a constant emissivity less than 1 and a non-gray body has an emissivity which varies with wavelength. The emissivity and reflectivity of the surface is determined over a range of wavelengths. Spectra are also measured of the extraneous interference radiation source and the surface of the object to be measured in the presence of the extraneous interference radiation source. An auxiliary radiation source is used to determine the reflectivity of the surface and also the emissivity. The measured spectrum of the surfaces in the presence of the extraneous interference radiation source is set equal to the emissivity of the surface multiplied by a Planck function containing a temperature term T plus the surface reflectivity multiplied by the spectrum of the extraneous interference radiation source. The equation is then solved for T to determine the temperature of the surface.

NMR-based Metabolomics Analysis of Liver from C57BL/6 Mouse Exposed to Ionizing Radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiao, Xiongjie; Hu, Mary; Zhang, Xu

The health effects of exposing to ionizing radiation are attracting great interest in the space exploration community and patients considering radiotherapy. However, the impact to metabolism after exposure to high dose radiation has not yet been clearly defined in livers. In the present study, 1H nuclear magnetic resonance (NMR) based metabolomics combined with multivariate data analysis are applied to study the changes of metabolism in the liver of C57BL/6 mouse after whole body exposure to either gamma (3.0 and 7.8 Gy) or proton (3.0 Gy) radiation. Principal component analysis (PCA) and orthogonal projection to latent structures analysis (OPLS) are employedmore » for classification and identification of potential biomarkers associated with gamma and proton irradiation. The results show that the radiation exposed groups can be well separated from the control group. At the same radiation dosage, the group exposed to proton radiation is well separated from the group exposed to gamma radiation, indicating different radiation sources induce different alterations based on metabolic profiling. Common to both gamma and proton radiation at the high radiation doses studied in this work, compared with the control groups the concentrations of choline, O-phosphocholine and trimethylamine N-oxide are decreased statistically, while those of glutamine, glutathione, malate, creatinine, phosphate, betaine and 4-hydroxyphenylacetate are statistically and significantly elevated after exposure to radiation. Since these altered metabolites are associated with multiple biological pathways, the changes suggest that the exposure to radiation induce abnormality in multiple biological pathways. In particular, metabolites such as 4-hydroxyphenylacetate, betaine, glutamine, choline and trimethylamine N-oxide may be good candidates of pre-diagnose biomarkers for ionizing radiation in liver.« less

Optical radiation measurements: instrumentation and sources of error.

PubMed

Landry, R J; Andersen, F A

1982-07-01

Accurate measurement of optical radiation is required when sources of this radiation are used in biological research. The most difficult measurements of broadband noncoherent optical radiations usually must be performed by a highly trained specialist using sophisticated, complex, and expensive instruments. Presentation of the results of such measurement requires correct use of quantities and units with which many biological researchers are unfamiliar. The measurement process, physical quantities and units, measurement systems with instruments, and sources of error and uncertainties associated with optical radiation measurements are reviewed.

Active control of noise on the source side of a partition to increase its sound isolation

NASA Astrophysics Data System (ADS)

Tarabini, Marco; Roure, Alain; Pinhede, Cedric

2009-03-01

This paper describes a local active noise control system that virtually increases the sound isolation of a dividing wall by means of a secondary source array. With the proposed method, sound pressure on the source side of the partition is reduced using an array of loudspeakers that generates destructive interference on the wall surface, where an array of error microphones is placed. The reduction of sound pressure on the incident side of the wall is expected to decrease the sound radiated into the contiguous room. The method efficiency was experimentally verified by checking the insertion loss of the active noise control system; in order to investigate the possibility of using a large number of actuators, a decentralized FXLMS control algorithm was used. Active control performances and stability were tested with different array configurations, loudspeaker directivities and enclosure characteristics (sound source position and absorption coefficient). The influence of all these parameters was investigated with the factorial design of experiments. The main outcome of the experimental campaign was that the insertion loss produced by the secondary source array, in the 50-300 Hz frequency range, was close to 10 dB. In addition, the analysis of variance showed that the active noise control performance can be optimized with a proper choice of the directional characteristics of the secondary source and the distance between loudspeakers and error microphones.

The effects of simulated low Earth orbit environments on spacecraft thermal control coatings

NASA Technical Reports Server (NTRS)

Dever, Joyce A.; Rutledge, Sharon K.; Bruckner, Eric J.; Stidham, Curtis R.; Stueber, Thomas J.; Booth, Roy E.

1993-01-01

Candidate Space Station Freedom radiator coatings including Z-93, YB-71, anodized aluminum and SiO(x) coated silvered Teflon have been characterized for optical properties degradation upon exposure to environments containing atomic oxygen, vacuum ultraviolet (VUV) radiation, and/or silicone contamination. YB-71 coating showed a blue-gray discoloration, which has not been observed in space, upon exposure in atomic oxygen facilities which also provide exaggerated VUV radiation. This is evidence that damage mechanisms occur in these ground laboratory facilities which are different from those which occur in space. Radiator coatings exposed to an electron cyclotron resonance (ECR) atomic oxygen source in the presence of silicone-containing samples showed severe darkening from the intense VUV radiation provided by the ECR and from silicone contamination. Samples exposed to atomic oxygen from the ECR source and to VUV lamps, simultaneously, with in situ reflectance measurement, showed that significantly greater degradation occurred when samples received line-of-site ECR beam exposure than when samples were exposed to atomic oxygen scattered off of quartz surfaces without line-of-site view of the ECR beam. For white paints, exposure to air following atomic oxygen/VUV exposure reversed the darkening due to VUV damage. This illustrates the importance of in situ reflectance measurement.

Glass Membrane For Controlled Diffusion Of Gases

DOEpatents

Shelby, James E.; Kenyon, Brian E.

2001-05-15

A glass structure for controlled permeability of gases includes a glass vessel. The glass vessel has walls and a hollow center for receiving a gas. The glass vessel contains a metal oxide dopant formed with at least one metal selected from the group consisting of transition metals and rare earth metals for controlling diffusion of the gas through the walls of the glass vessel. The vessel releases the gas through its walls upon exposure to a radiation source.

A source-attractor approach to network detection of radiation sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Qishi; Barry, M. L..; Grieme, M.

Radiation source detection using a network of detectors is an active field of research for homeland security and defense applications. We propose Source-attractor Radiation Detection (SRD) method to aggregate measurements from a network of detectors for radiation source detection. SRD method models a potential radiation source as a magnet -like attractor that pulls in pre-computed virtual points from the detector locations. A detection decision is made if a sufficient level of attraction, quantified by the increase in the clustering of the shifted virtual points, is observed. Compared with traditional methods, SRD has the following advantages: i) it does not requiremore » an accurate estimate of the source location from limited and noise-corrupted sensor readings, unlike the localizationbased methods, and ii) its virtual point shifting and clustering calculation involve simple arithmetic operations based on the number of detectors, avoiding the high computational complexity of grid-based likelihood estimation methods. We evaluate its detection performance using canonical datasets from Domestic Nuclear Detection Office s (DNDO) Intelligence Radiation Sensors Systems (IRSS) tests. SRD achieves both lower false alarm rate and false negative rate compared to three existing algorithms for network source detection.« less

Plutonium radiation surrogate

DOEpatents

Frank, Michael I [Dublin, CA

2010-02-02

A self-contained source of gamma-ray and neutron radiation suitable for use as a radiation surrogate for weapons-grade plutonium is described. The source generates a radiation spectrum similar to that of weapons-grade plutonium at 5% energy resolution between 59 and 2614 keV, but contains no special nuclear material and emits little .alpha.-particle radiation. The weapons-grade plutonium radiation surrogate also emits neutrons having fluxes commensurate with the gamma-radiation intensities employed.

A Modelica-based Model Library for Building Energy and Control Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wetter, Michael

2009-04-07

This paper describes an open-source library with component models for building energy and control systems that is based on Modelica, an equation-based objectoriented language that is well positioned to become the standard for modeling of dynamic systems in various industrial sectors. The library is currently developed to support computational science and engineering for innovative building energy and control systems. Early applications will include controls design and analysis, rapid prototyping to support innovation of new building systems and the use of models during operation for controls, fault detection and diagnostics. This paper discusses the motivation for selecting an equation-based object-oriented language.more » It presents the architecture of the library and explains how base models can be used to rapidly implement new models. To demonstrate the capability of analyzing novel energy and control systems, the paper closes with an example where we compare the dynamic performance of a conventional hydronic heating system with thermostatic radiator valves to an innovative heating system. In the new system, instead of a centralized circulation pump, each of the 18 radiators has a pump whose speed is controlled using a room temperature feedback loop, and the temperature of the boiler is controlled based on the speed of the radiator pump. All flows are computed by solving for the pressure distribution in the piping network, and the controls include continuous and discrete time controls.« less

Analytical study of acoustic response of a semireverberant enclosure with application to active noise control

NASA Technical Reports Server (NTRS)

Parrott, T. L.; Schein, D. B.; Gridley, D.

1985-01-01

The acoustic response of a semireverberant enclosure with two interacting, velocity-prescribed source distributions was analyzed using standard modal analysis techniques with a view toward a better understanding of active noise control. Different source and enclosure dimensions, source separations, and single-wall admittances were studied over representative frequency bandwidths of 10 Hz with source relative phase as a parameter. Results indicate that power radiated into the enclosure agree qualitatively with the spatial average of the mean square pressure, even though the reverberant field is nondiffuse. Decreases in acoustic power can therefore be used to estimate global noise reduction in a nondiffuse semireverberant environment. As might be expected, parametric studies indicate that maximum power reductions of up to 25 dB can be achieved when secondary and primary sources are compact and closely spaced. Although less success is achieved with increasing frequency and source separation or size, significant suppression of up to 8 dB still occurs over the 1 to 2 Hz bandwidth.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hillmer, Kurt T.

radioactive source is material used for its emitted radiation. Sources are sealed or unsealed and are classified as accountable or exempt. Radioactive sources are used for response checks, functional checks, and the calibration of instruments and monitors to traceable standards. To ensure the safety and welfare of all personnel, it is important to maintain control of radioactive sources to minimize the potential for the spread of contamination, unnecessary exposure to personnel, loss or theft, and improper disposal. This course will prepare the student with the skills necessary for RCT qualification by passing quizzes, tests, and the RCT Comprehensive Phase 1,more » Unit 2 Examination (TEST 27566) and will provide in-the-field skills.« less

Thermal Image Sensing Model for Robotic Planning and Search

PubMed Central

Castro Jiménez, Lídice E.; Martínez-García, Edgar A.

2016-01-01

This work presents a search planning system for a rolling robot to find a source of infra-red (IR) radiation at an unknown location. Heat emissions are observed by a low-cost home-made IR passive visual sensor. The sensor capability for detection of radiation spectra was experimentally characterized. The sensor data were modeled by an exponential model to estimate the distance as a function of the IR image’s intensity, and, a polynomial model to estimate temperature as a function of IR intensities. Both theoretical models are combined to deduce a subtle nonlinear exact solution via distance-temperature. A planning system obtains feed back from the IR camera (position, intensity, and temperature) to lead the robot to find the heat source. The planner is a system of nonlinear equations recursively solved by a Newton-based approach to estimate the IR-source in global coordinates. The planning system assists an autonomous navigation control in order to reach the goal and avoid collisions. Trigonometric partial differential equations were established to control the robot’s course towards the heat emission. A sine function produces attractive accelerations toward the IR source. A cosine function produces repulsive accelerations against the obstacles observed by an RGB-D sensor. Simulations and real experiments of complex indoor are presented to illustrate the convenience and efficacy of the proposed approach. PMID:27509510

Vertical intensity modulation for improved radiographic penetration and reduced exclusion zone

NASA Astrophysics Data System (ADS)

Bendahan, J.; Langeveld, W. G. J.; Bharadwaj, V.; Amann, J.; Limborg, C.; Nosochkov, Y.

2016-09-01

In the present work, a method to direct the X-ray beam in real time to the desired locations in the cargo to increase penetration and reduce exclusion zone is presented. Cargo scanners employ high energy X-rays to produce radiographic images of the cargo. Most new scanners employ dual-energy to produce, in addition to attenuation maps, atomic number information in order to facilitate the detection of contraband. The electron beam producing the bremsstrahlung X-ray beam is usually directed approximately to the center of the container, concentrating the highest X-ray intensity to that area. Other parts of the container are exposed to lower radiation levels due to the large drop-off of the bremsstrahlung radiation intensity as a function of angle, especially for high energies (>6 MV). This results in lower penetration in these areas, requiring higher power sources that increase the dose and exclusion zone. The capability to modulate the X-ray source intensity on a pulse-by-pulse basis to deliver only as much radiation as required to the cargo has been reported previously. This method is, however, controlled by the most attenuating part of the inspected slice, resulting in excessive radiation to other areas of the cargo. A method to direct a dual-energy beam has been developed to provide a more precisely controlled level of required radiation to highly attenuating areas. The present method is based on steering the dual-energy electron beam using magnetic components on a pulse-to-pulse basis to a fixed location on the X-ray production target, but incident at different angles so as to direct the maximum intensity of the produced bremsstrahlung to the desired locations. The details of the technique and subsystem and simulation results are presented.

Basics of particle therapy I: physics

PubMed Central

Park, Seo Hyun

2011-01-01

With the advance of modern radiation therapy technique, radiation dose conformation and dose distribution have improved dramatically. However, the progress does not completely fulfill the goal of cancer treatment such as improved local control or survival. The discordances with the clinical results are from the biophysical nature of photon, which is the main source of radiation therapy in current field, with the lower linear energy transfer to the target. As part of a natural progression, there recently has been a resurgence of interest in particle therapy, specifically using heavy charged particles, because these kinds of radiations serve theoretical advantages in both biological and physical aspects. The Korean government is to set up a heavy charged particle facility in Korea Institute of Radiological & Medical Sciences. This review introduces some of the elementary physics of the various particles for the sake of Korean radiation oncologists' interest. PMID:22984664

Optical Radiation from Shock-Compressed Materials. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Svendsen, Robert F., Jr.

1987-01-01

Recent observations of shock-induced radiation from oxides, silicates, and metals of geophysical interest constrain the shock-compressed temperature of these materials. The relationships between the temperature inferred from the observed radiation and the temperature of the shock-compressed film or foil and/or window were investigated. Changes of the temperature field in each target component away from that of their respective shock-compressed states occur because of: shock-impedance mismatch between target components; thermal mismatch between target components; surface roughness at target interfaces; and conduction within and between target components. In particular, conduction may affect the temperature of the film/foil window interface on the time scale of the experiments, and so control the intensity and history of the dominant thermal radiation sources in the target. This type of model was used to interpret the radiation emitted by a variety of shock-compressed materials and interfaces.

Recent advances in radiation cancer therapy

NASA Astrophysics Data System (ADS)

Ma, C.-M. Charlie

2007-03-01

This paper presents the recent advances in radiation therapy techniques for the treatment of cancer. Significant improvement has been made in imaging techniques such as CT, MRI, MRS, PET, ultrasound, etc. that have brought marked advances in tumor target and critical structure delineation for treatment planning and patient setup and target localization for accurate dose delivery in radiation therapy of cancer. Recent developments of novel treatment modalities including intensity-modulated x-ray therapy (IMXT), energy- and intensity modulated electron therapy (MERT) and intensity modulated proton therapy (IMPT) together with the use of advanced image guidance have enabled precise dose delivery for dose escalation and hypofractionation studies that may result in better local control and quality of life. Particle acceleration using laser-induced plasmas has great potential for new cost-effective radiation sources that may have a great impact on the management of cancer using radiation therapy.

ReactorHealth Physics operations at the NIST center for neutron research.

PubMed

Johnston, Thomas P

2015-02-01

Performing health physics and radiation safety functions under a special nuclear material license and a research and test reactor license at a major government research and development laboratory encompasses many elements not encountered by industrial, general, or broad scope licenses. This article reviews elements of the health physics and radiation safety program at the NIST Center for Neutron Research, including the early history and discovery of the neutron, applications of neutron research, reactor overview, safety and security of radiation sources and radioactive material, and general health physics procedures. These comprise precautions and control of tritium, training program, neutron beam sample processing, laboratory audits, inventory and leak tests, meter calibration, repair and evaluation, radioactive waste management, and emergency response. In addition, the radiation monitoring systems will be reviewed including confinement building monitoring, ventilation filter radiation monitors, secondary coolant monitors, gaseous fission product monitors, gas monitors, ventilation tritium monitor, and the plant effluent monitor systems.

Adaptive prospective ECG-triggered sequence coronary angiography in dual-source CT without heart rate control: Image quality and diagnostic performance.

PubMed

Pan, Chang-Jie; Qian, Nong; Wang, Tao; Tang, Xiao-Qiang; Xue, Yue-Jun

2013-02-01

The aim of this study was to evaluate the accuracy of using second generation dual-source CT (DSCT) to obtain high quality images and diagnostic performance and to reduce the radiation dose in adaptive prospective electrocardiography (ECG)-triggered sequence (CorAdSeq) CT coronary angiography (CTCA) without heart rate control. No prescan β-blockers were administered. Un-enhanced CT and CTCA with adaptive prospective CorAdSeq scanning without heart rate control were performed in 683 consecutive patients divided into two body mass index (BMI) groups: BMI <25 kg/m(2) (group A, n=412) and BMI ≥25 kg/m(2) (group B, n=271). The image quality and quantitative stenosis of all coronary segments with a diameter ≥1 mm were assessed. The mean heart rate (MHR), heart rate variability (HRV) and radiation dose values were recorded. In 426 cases, the diagnostic performance was evaluated using quantitative conventional coronary angiography as the reference standard. Diagnostic image quality was obtained in 98.5% of segments in group A and in 98.8% of segments in group B, with no significant differences between the groups. No correlations were observed between the image quality score and MHR or HRV (P=0.492, P=0.564, respectively). The effective radiation doses in groups A and B were 2.57±1.01 mSv and 6.36±1.88 mSv, respectively. The sensitivities and specificities of diagnosing coronary heart disease per patient were 99.6% and 97.8% in group A and 99.5% and 97.5% in group B, respectively (P>0.05). Adaptive prospective CorAdSeq scanning, without heart rate control, by second generation DSCT had a high image quality and diagnostic performance for coronary artery stenosis with lower radiation doses.

Radioactive materials in recycled metals.

PubMed

Lubenau, J O; Yusko, J G

1995-04-01

In recent years, the metal recycling industry has become increasingly aware of an unwanted component in metal scrap--radioactive material. Worldwide, there have been 35 instances where radioactive sources were unintentionally smelted in the course of recycling metal scrap. In some cases contaminated metal consumer products were distributed internationally. In at least one case, serious radiation exposures of workers and the public occurred. Radioactive material appearing in metal scrap includes sources subject to licensing under the Atomic Energy Act and also naturally occurring radioactive material. U.S. mills that have smelted a radioactive source face costs resulting from decontamination, waste disposal, and lost profits that range from 7 to 23 million U.S. dollars for each event. To solve the problem, industry and the government have jointly undertaken initiatives to increase awareness of the problem within the metal recycling industry. Radiation monitoring of recycled metal scrap is being performed increasingly by mills and, to a lesser extent, by scrap processors. The monitoring does not, however, provide 100% protection. Improvements in regulatory oversight by the government could stimulate improved accounting and control of licensed sources. However, additional government effort in this area must be reconciled with competing priorities in radiation safety and budgetary constraints. The threat of radioactive material in recycled metal scrap will continue for the foreseeable future and, thus, poses regulatory policy challenges for both developed and developing nations.

THz and Sub-THz Capabilities of a Table-Top Radiation Source Driven by an RF Thermionic Electron Gun

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smirnov, Alexei V.; Agustsson, R.; Boucher, S.

Design features and experimental results are presented for a sub-mm wave source [1] based on APS RF thermionic electron gun. The setup includes compact alpha-magnet, quadrupoles, sub-mm-wave radiators, and THz optics. The sub-THz radiator is a planar, oversized structure with gratings. Source upgrade for generation frequencies above 1 THz is discussed. The THz radiator will use a short-period undulator having 1 T field amplitude, ~20 cm length, and integrated with a low-loss oversized waveguide. Both radiators are integrated with a miniature horn antenna and a small ~90°-degree in-vacuum bending magnet. The electron beamline is designed to operate different modes includingmore » conversion to a flat beam interacting efficiently with the radiator. The source can be used for cancer diagnostics, surface defectoscopy, and non-destructive testing. Sub-THz experiment demonstrated a good potential of a robust, table-top system for generation of a narrow bandwidth THz radiation. This setup can be considered as a prototype of a compact, laser-free, flexible source capable of generation of long trains of Sub-THz and THz pulses with repetition rates not available with laser-driven sources.« less

Ultra Low-Dose Radiation: Stress Responses and Impacts Using Rice as a Grass Model

PubMed Central

Rakwal, Randeep; Agrawal, Ganesh Kumar; Shibato, Junko; Imanaka, Tetsuji; Fukutani, Satoshi; Tamogami, Shigeru; Endo, Satoru; Sahoo, Sarata Kumar; Masuo, Yoshinori; Kimura, Shinzo

2009-01-01

We report molecular changes in leaves of rice plants (Oryza sativa L. - reference crop plant and grass model) exposed to ultra low-dose ionizing radiation, first using contaminated soil from the exclusion zone around Chernobyl reactor site. Results revealed induction of stress-related marker genes (Northern blot) and secondary metabolites (LC-MS/MS) in irradiated leaf segments over appropriate control. Second, employing the same in vitro model system, we replicated results of the first experiment using in-house fabricated sources of ultra low-dose gamma (γ) rays and selected marker genes by RT-PCR. Results suggest the usefulness of the rice model in studying ultra low-dose radiation response/s. PMID:19399245

Modeling of Ultrasonic and Terahertz Radiations in Defective Tiles for Condition Monitoring of Thermal Protection Systems

DTIC Science & Technology

2013-04-01

different ultrasonic and electromagnetic field modeling problems for NDE (nondestructive evaluation) applications [5- 14]. 2d . Use of the...transient ultrasonic wave propagation using the Distributed Point Source Method”, IEEE Transactions on Ultrasonics, Ferroelectric and Frequency Control...Cavity”, IEEE Transactions on Ultrasonics, Ferroelectric and Frequency Control, Vol. 57(6), pp. 1396-1404, 2010. [10] A. Shelke, S. Das and T. Kundu

Detailed observations of the source of terrestrial narrowband electromagnetic radiation

NASA Technical Reports Server (NTRS)

Kurth, W. S.

1982-01-01

Detailed observations are presented of a region near the terrestrial plasmapause where narrowband electromagnetic radiation (previously called escaping nonthermal continuum radiation) is being generated. These observations show a direct correspondence between the narrowband radio emissions and electron cyclotron harmonic waves near the upper hybrid resonance frequency. In addition, electromagnetic radiation propagating in the Z-mode is observed in the source region which provides an extremely accurate determination of the electron plasma frequency and, hence, density profile of the source region. The data strongly suggest that electrostatic waves and not Cerenkov radiation are the source of the banded radio emissions and define the coupling which must be described by any viable theory.

Enhanced radiation resistant fiber optics

DOEpatents

Lyons, Peter B.; Looney, Larry D.

1993-01-01

A process for producing an optical fiber having enhanced radiation resitance is provided, the process including maintaining an optical fiber within a hydrogen-containing atmosphere for sufficient time to yield a hydrogen-permeated optical fiber having an elevated internal hydrogen concentration, and irradiating the hydrogen-permeated optical fiber at a time while the optical fiber has an elevated internal hydrogen concentration with a source of ionizing radiation. The radiation source is typically a cobalt-60 source and the fiber is pre-irradiated with a dose level up to about 1000 kilorads of radiation.

Enhanced radiation resistant fiber optics

DOEpatents

Lyons, P.B.; Looney, L.D.

1993-11-30

A process for producing an optical fiber having enhanced radiation resistance is provided, the process including maintaining an optical fiber within a hydrogen-containing atmosphere for sufficient time to yield a hydrogen-permeated optical fiber having an elevated internal hydrogen concentration, and irradiating the hydrogen-permeated optical fiber at a time while the optical fiber has an elevated internal hydrogen concentration with a source of ionizing radiation. The radiation source is typically a cobalt-60 source and the fiber is pre-irradiated with a dose level up to about 1000 kilorads of radiation. 4 figures.

EXPERIMENTS - APOLLO 17

NASA Image and Video Library

1972-11-17

S72-53470 (November 1972) --- The Far-Ultraviolet Spectrometer, Experiment S-169, one of the lunar orbital science experiments which will be mounted in the SIM bay of the Apollo 17 Service Module. Controls for activating and deactivating the experiment and for opening and closing a protective cover are located in the Command Module. Atomic composition, density and scale height for several constituents of the lunar atmosphere will be measured by the far-ultraviolet spectrometer. Solar far-UV radiation reflected from the lunar surface as well as UV radiation emitted by galactic sources also will be detected by the instrument.

A radiation quality correction factor k for well-type ionization chambers for the measurement of the reference air kerma rate of (60)Co HDR brachytherapy sources.

PubMed

Schüller, Andreas; Meier, Markus; Selbach, Hans-Joachim; Ankerhold, Ulrike

2015-07-01

The aim of this study was to investigate whether a chamber-type-specific radiation quality correction factor kQ can be determined in order to measure the reference air kerma rate of (60)Co high-dose-rate (HDR) brachytherapy sources with acceptable uncertainty by means of a well-type ionization chamber calibrated for (192)Ir HDR sources. The calibration coefficients of 35 well-type ionization chambers of two different chamber types for radiation fields of (60)Co and (192)Ir HDR brachytherapy sources were determined experimentally. A radiation quality correction factor kQ was determined as the ratio of the calibration coefficients for (60)Co and (192)Ir. The dependence on chamber-to-chamber variations, source-to-source variations, and source strength was investigated. For the PTW Tx33004 (Nucletron source dosimetry system (SDS)) well-type chamber, the type-specific radiation quality correction factor kQ is 1.19. Note that this value is valid for chambers with the serial number, SN ≥ 315 (Nucletron SDS SN ≥ 548) onward only. For the Standard Imaging HDR 1000 Plus well-type chambers, the type-specific correction factor kQ is 1.05. Both kQ values are independent of the source strengths in the complete clinically relevant range. The relative expanded uncertainty (k = 2) of kQ is UkQ = 2.1% for both chamber types. The calibration coefficient of a well-type chamber for radiation fields of (60)Co HDR brachytherapy sources can be calculated from a given calibration coefficient for (192)Ir radiation by using a chamber-type-specific radiation quality correction factor kQ. However, the uncertainty of a (60)Co calibration coefficient calculated via kQ is at least twice as large as that for a direct calibration with a (60)Co source.

Measurement of wood/plant cell or composite material attributes with computer assisted tomography

DOEpatents

West, Darrell C.; Paulus, Michael J.; Tuskan, Gerald A.; Wimmer, Rupert

2004-06-08

A method for obtaining wood-cell attributes from cellulose containing samples includes the steps of radiating a cellulose containing sample with a beam of radiation. Radiation attenuation information is collected from radiation which passes through the sample. The source is rotated relative to the sample and the radiation and collecting steps repeated. A projected image of the sample is formed from the collected radiation attenuation information, the projected image including resolvable features of the cellulose containing sample. Cell wall thickness, cell diameter (length) and cell vacoule diameter can be determined. A system for obtaining physical measures from cellulose containing samples includes a radiation source, a radiation detector, and structure for rotating the source relative to said sample. The system forms an image of the sample from the radiation attenuation information, the image including resolvable features of the sample.

10 CFR 32.74 - Manufacture and distribution of sources or devices containing byproduct material for medical use.

Code of Federal Regulations, 2013 CFR

2013-01-01

... accidents; (iv) For devices containing byproduct material, the radiation profile of a prototype device; (v... source or device pertinent to an evaluation of its radiation safety, including: (i) The byproduct...) Instructions for handling and storing the source or device from the radiation safety standpoint; these...

10 CFR 32.74 - Manufacture and distribution of sources or devices containing byproduct material for medical use.

Code of Federal Regulations, 2014 CFR

2014-01-01

... accidents; (iv) For devices containing byproduct material, the radiation profile of a prototype device; (v... source or device pertinent to an evaluation of its radiation safety, including: (i) The byproduct...) Instructions for handling and storing the source or device from the radiation safety standpoint; these...

Analog synthesized fast-variable linear load

NASA Technical Reports Server (NTRS)

Niedra, Janis M.

1991-01-01

A several kilowatt power level, fast-variable linear resistor was synthesized by using analog components to control the conductance of power MOSFETs. Risetimes observed have been as short as 500 ns with respect to the control signal and 1 to 2 microseconds with respect to the power source voltage. A variant configuration of this load that dissipates a constant power set by a control signal is indicated. Replacement of the MOSFETs by static induction transistors (SITs) to increase power handling, speed and radiation hardness is discussed.

The generation of gravitational waves. I - Weak-field sources

NASA Technical Reports Server (NTRS)

Thorne, K. S.; Kovacs, S. J.

1975-01-01

This paper derives and summarizes a 'plug-in-and-grind' formalism for calculating the gravitational waves emitted by any system with weak internal gravitational fields. If the internal fields have negligible influence on the system's motions, the formalism reduces to standard 'linearized theory'. Independent of the effects of gravity on the motions, the formalism reduces to the standard 'quadrupole-moment formalism' if the motions are slow and internal stresses are weak. In the general case, the formalism expresses the radiation in terms of a retarded Green's function for slightly curved spacetime and breaks the Green's function integral into five easily understood pieces: direct radiation, produced directly by the motions of the source; whump radiation, produced by the 'gravitational stresses' of the source; transition radiation, produced by a time-changing time delay ('Shapiro effect') in the propagation of the nonradiative 1/r field of the source; focusing radiation, produced when one portion of the source focuses, in a time-dependent way, the nonradiative field of another portion of the source; and tail radiation, produced by 'back-scatter' of the nonradiative field in regions of focusing.

The generation of gravitational waves. 1. Weak-field sources: A plug-in-and-grind formalism

NASA Technical Reports Server (NTRS)

Thorne, K. S.; Kovacs, S. J.

1974-01-01

A plug-in-and-grind formalism is derived for calculating the gravitational waves emitted by any system with weak internal gravitational fields. If the internal fields have negligible influence on the system's motions, then the formalism reduces to standard linearized theory. Whether or not gravity affects the motions, if the motions are slow and internal stresses are weak, then the new formalism reduces to the standard quadrupole-moment formalism. In the general case the new formalism expresses the radiation in terms of a retarded Green's function for slightly curved spacetime, and then breaks the Green's-function integral into five easily understood pieces: direct radiation, produced directly by the motions of the sources; whump radiation, produced by the the gravitational stresses of the source; transition radiation, produced by a time-changing time delay (Shapiro effect) in the propagation of the nonradiative, 1/r field of the source; focussing radiation produced when one portion of the source focusses, in a time-dependent way, the nonradiative field of another portion of the source, and tail radiation, produced by backscatter of the nonradiative field in regions of focussing.

Radiation Protection

NASA Astrophysics Data System (ADS)

Grupen, Claus

Radiation protection is a very important aspect for the application of particle detectors in many different fields, like high energy physics, medicine, materials science, oil and mineral exploration, and arts, to name a few. The knowledge of radiation units, the experience with shielding, and information on biological effects of radiation are vital for scientists handling radioactive sources or operating accelerators or X-ray equipment. This article describes the modern radiation units and their conversions to older units which are still in use in many countries. Typical radiation sources and detectors used in the field of radiation protection are presented. The legal regulations in nearly all countries follow closely the recommendations of the International Commission on Radiological Protection (ICRP). Tables and diagrams with relevant information on the handling of radiation sources provide useful data for the researcher working in this field.

Synchronous identification of friendly targets

DOEpatents

Telle, John M.; Roger, Stutz A.

1998-01-01

A synchronous communication targeting system for use in battle. The present invention includes a transceiver having a stabilizing oscillator, a synchronous amplifier and an omnidirectional receiver, all in electrical communication with each other. A remotely located beacon is attached to a blackbody radiation source and has an amplitude modulator in electrical communication with a optical source. The beacon's amplitude modulator is set so that the optical source transmits radiation frequency at approximately the same or lower amplitude than that of the blackbody radiation source to which the beacon is attached. The receiver from the transceiver is adapted to receive frequencies approximately at or below blackbody radiation signals and sends such signals to the synchronous amplifier. The synchronous amplifier then rectifies and amplifies those signals which correspond to the predetermined frequency to therefore identify whether the blackbody radiation source is friendly or not.

Spontaneous Raman scattering as a high resolution XUV radiation source

NASA Technical Reports Server (NTRS)

Rothenberg, J. E.; Young, J. F.; Harris, S. E.

1983-01-01

A type of high resolution XUV radiation source is described which is based upon spontaneous anti-Stokes scattering of tunable incident laser radiation from atoms excited to metastable levels. The theory of the source is summarized and two sets of experiments using He (1s2s)(1)S atoms, produced in a cw hollow cathode and in a pulsed high power microwave discharge, are discussed. The radiation source is used to examine transitions originating from the 3p(6) shell of potassium. The observed features include four previously unreported absorption lines and several sharp interferences of closely spaced autoionizing lines. A source linewidth of about 1.9 cm(-1) at 185,000 cm(-1) is demonstrated.

Optical Imaging of Ionizing Radiation from Clinical Sources

PubMed Central

Shaffer, Travis M.; Drain, Charles Michael

2016-01-01

Nuclear medicine uses ionizing radiation for both in vivo diagnosis and therapy. Ionizing radiation comes from a variety of sources, including x-rays, beam therapy, brachytherapy, and various injected radionuclides. Although PET and SPECT remain clinical mainstays, optical readouts of ionizing radiation offer numerous benefits and complement these standard techniques. Furthermore, for ionizing radiation sources that cannot be imaged using these standard techniques, optical imaging offers a unique imaging alternative. This article reviews optical imaging of both radionuclide- and beam-based ionizing radiation from high-energy photons and charged particles through mechanisms including radioluminescence, Cerenkov luminescence, and scintillation. Therapeutically, these visible photons have been combined with photodynamic therapeutic agents preclinically for increasing therapeutic response at depths difficult to reach with external light sources. Last, new microscopy methods that allow single-cell optical imaging of radionuclides are reviewed. PMID:27688469

Implementation of irradiation of pork for trichina control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Engel, R.E.; Post, A.R.; Post, R.C.

1988-07-01

This article describes the attempts to develop adequate regulatory framework for the use of ionizing radiations in the preservation of food. To be successful, a uniform set of guidelines are needed for the selection, calibration, and application of dosimetry systems; clearance of packaging materials; labeling information; and consumer education programs are essential. The primary regulatory agency that food processors must satisfy is the US FDA. In 1985, in response to an industry petition, the FDA amended its food additive regulations to permit the use of gamma radiation sources to irradiate fresh, non-heat processed pork cuts or carcasses to control Trichinellaspiralis.more » The regulation permits irradiation of only fresh pork within a dose range of 0.3 to 1 kGy.« less

The Natural Radiation Environment, Understanding the Atom Series.

ERIC Educational Resources Information Center

Kastner, Jacob

The somatic and genetic effects of naturally occurring radiation are described in this illustrated booklet. Internal sources of radiation from food, water, and air and external sources including radioisotopes in rock, brick, water, and air and cosmic radiation are tabulated. Detection methods are described, and their use in biological and physical…

10 CFR 34.21 - Limits on external radiation levels from storage containers and source changers.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Limits on external radiation levels from storage... INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Equipment § 34.21 Limits on external radiation levels from storage containers and source changers. The maximum...

10 CFR 34.21 - Limits on external radiation levels from storage containers and source changers.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Limits on external radiation levels from storage... INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Equipment § 34.21 Limits on external radiation levels from storage containers and source changers. The maximum...

10 CFR 34.21 - Limits on external radiation levels from storage containers and source changers.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Limits on external radiation levels from storage... INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Equipment § 34.21 Limits on external radiation levels from storage containers and source changers. The maximum...

10 CFR 34.21 - Limits on external radiation levels from storage containers and source changers.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Limits on external radiation levels from storage... INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Equipment § 34.21 Limits on external radiation levels from storage containers and source changers. The maximum...

10 CFR 34.21 - Limits on external radiation levels from storage containers and source changers.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Limits on external radiation levels from storage... INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Equipment § 34.21 Limits on external radiation levels from storage containers and source changers. The maximum...

Non-Thermal Electromagnetic Radiation Damage to Lens Epithelium

PubMed Central

Bormusov, Elvira; P.Andley, Usha; Sharon, Naomi; Schächter, Levi; Lahav, Assaf; Dovrat, Ahuva

2008-01-01

High frequency microwave electromagnetic radiation from mobile phones and other modern devices has the potential to damage eye tissues, but its effect on the lens epithelium is unknown at present. The objective of this study was to investigate the non-thermal effects of high frequency microwave electromagnetic radiation (1.1GHz, 2.22 mW) on the eye lens epithelium in situ. Bovine lenses were incubated in organ culture at 35°C for 10-15 days. A novel computer-controlled microwave source was used to investigate the effects of microwave radiation on the lenses. 58 lenses were used in this study. The lenses were divided into four groups: (1) Control lenses incubated in organ culture for 10 to15 days. (2) Electromagnetic radiation exposure group treated with 1.1 GHz, 2.22 mW microwave radiation for 90 cycles of 50 minutes irradiation followed by 10 minutes pause and cultured up to 10 days. (3) Electromagnetic radiation exposure group treated as group 2 with 192 cycles of radiation and cultured for 15 days. (4) Lenses exposed to 39.5ºC for 2 hours 3 times with 24 hours interval after each treatment beginning on the second day of the culture and cultured for 11 days. During the culture period, lens optical quality was followed daily by a computer-operated scanning laser beam. At the end of the culture period, control and treated lenses were analyzed morphologically and by assessment of the lens epithelial ATPase activity. Exposure to 1.1 GHz, 2.22 mW microwaves caused a reversible decrease in lens optical quality accompanied by irreversible morphological and biochemical damage to the lens epithelial cell layer. The effect of the electromagnetic radiation on the lens epithelium was remarkably different from those of conductive heat. The results of this investigation showed that electromagnetic fields from microwave radiation have a negative impact on the eye lens. The lens damage by electromagnetic fields was distinctly different from that caused by conductive heat. PMID:19517034

The electromagnetic radiation from simple sources in the presence of a homogeneous dielectric sphere

NASA Technical Reports Server (NTRS)

Mason, V. B.

1973-01-01

In this research, the effect of a homogeneous dielectric sphere on the electromagnetic radiation from simple sources is treated as a boundary value problem, and the solution is obtained by the technique of dyadic Green's functions. Exact representations of the electric fields in the various regions due to a source located inside, outside, or on the surface of a dielectric sphere are formulated. Particular attention is given to the effect of sphere size, source location, dielectric constant, and dielectric loss on the radiation patterns and directivity of small spheres (less than 5 wavelengths in diameter) using the Huygens' source excitation. The computed results are found to closely agree with those measured for waveguide-excited plexiglas spheres. Radiation patterns for an extended Huygens' source and for curved electric dipoles located on the sphere's surface are also presented. The resonance phenomenon associated with the dielectric sphere is studied in terms of the modal representation of the radiated fields. It is found that when the sphere is excited at certain frequencies, much of the energy is radiated into the sidelobes. The addition of a moderate amount of dielectric loss, however, quickly attenuates this resonance effect. A computer program which may be used to calculate the directivity and radiation pattern of a Huygens' source located inside or on the surface of a lossy dielectric sphere is listed.

Monte Carlo simulation of radiation transport and dose deposition from locally released gold nanoparticles labeled with 111In, 177Lu or 90Y incorporated into tissue implantable depots

NASA Astrophysics Data System (ADS)

Lai, Priscilla; Cai, Zhongli; Pignol, Jean-Philippe; Lechtman, Eli; Mashouf, Shahram; Lu, Yijie; Winnik, Mitchell A.; Jaffray, David A.; Reilly, Raymond M.

2017-11-01

Permanent seed implantation (PSI) brachytherapy is a highly conformal form of radiation therapy but is challenged with dose inhomogeneity due to its utilization of low energy radiation sources. Gold nanoparticles (AuNP) conjugated with electron emitting radionuclides have recently been developed as a novel form of brachytherapy and can aid in homogenizing dose through physical distribution of radiolabeled AuNP when injected intratumorally (IT) in suspension. However, the distribution is unpredictable and precise placement of many injections would be difficult. Previously, we reported the design of a nanoparticle depot (NPD) that can be implanted using PSI techniques and which facilitates controlled release of AuNP. We report here the 3D dose distribution resulting from a NPD incorporating AuNP labeled with electron emitters (90Y, 177Lu, 111In) of different energies using Monte Carlo based voxel level dosimetry. The MCNP5 Monte Carlo radiation transport code was used to assess differences in dose distribution from simulated NPD and conventional brachytherapy sources, positioned in breast tissue simulating material. We further compare these dose distributions in mice bearing subcutaneous human breast cancer xenografts implanted with 177Lu-AuNP NPD, or injected IT with 177Lu-AuNP in suspension. The radioactivity distributions were derived from registered SPECT/CT images and time-dependent dose was estimated. Results demonstrated that the dose distribution from NPD reduced the maximum dose 3-fold when compared to conventional seeds. For simulated NPD, as well as NPD implanted in vivo, 90Y delivered the most homogeneous dose distribution. The tumor radioactivity in mice IT injected with 177Lu-AuNP redistributed while radioactivity in the NPD remained confined to the implant site. The dose distribution from radiolabeled AuNP NPD were predictable and concentric in contrast to IT injected radiolabeled AuNP, which provided irregular and temporally variant dose distributions. The use of NPD may serve as an intermediate between PSI and radiation delivered by radiolabeled AuNP by providing a controlled method to improve delivery of prescribed doses as well as homogenize dose from low penetrating electron sources.

Fast coincidence counting with active inspection systems

NASA Astrophysics Data System (ADS)

Mullens, J. A.; Neal, J. S.; Hausladen, P. A.; Pozzi, S. A.; Mihalczo, J. T.

2005-12-01

This paper describes 2nd and 3rd order time coincidence distributions measurements with a GHz processor that synchronously samples 5 or 10 channels of data from radiation detectors near fissile material. On-line, time coincidence distributions are measured between detectors or between detectors and an external stimulating source. Detector-to-detector correlations are useful for passive measurements also. The processor also measures the number of times n pulses occur in a selectable time window and compares this multiplet distribution to a Poisson distribution as a method of determining the occurrence of fission. The detectors respond to radiation emitted in the fission process induced internally by inherent sources or by external sources such as LINACS, DT generators either pulsed or steady state with alpha detectors, etc. Data can be acquired from prompt emission during the source pulse, prompt emissions immediately after the source pulse, or delayed emissions between source pulses. These types of time coincidence measurements (occurring on the time scale of the fission chain multiplication processes for nuclear weapons grade U and Pu) are useful for determining the presence of these fissile materials and quantifying the amount, and are useful for counter terrorism and nuclear material control and accountability. This paper presents the results for a variety of measurements.

Setup and Calibration of SLAC's Peripheral Monitoring Stations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cooper, C.

2004-09-03

The goals of this project were to troubleshoot, repair, calibrate, and establish documentation regarding SLAC's (Stanford Linear Accelerator Center's) PMS (Peripheral Monitoring Station) system. The PMS system consists of seven PMSs that continuously monitor skyshine (neutron and photon) radiation levels in SLAC's environment. Each PMS consists of a boron trifluoride (BF{sub 3}) neutron detector (model RS-P1-0802-104 or NW-G-20-12) and a Geiger Moeller (GM) gamma ray detector (model TGM N107 or LND 719) together with their respective electronics. Electronics for each detector are housed in Nuclear Instrument Modules (NIMs) and are plugged into a NIM bin in the station. All communicationmore » lines from the stations to the Main Control Center (MCC) were tested prior to troubleshooting. To test communication with MCC, a pulse generator (Systron Donner model 100C) was connected to each channel in the PMS and data at MCC was checked for consistency. If MCC displayed no data, the communication cables to MCC or the CAMAC (Computer Automated Measurement and Control) crates were in need of repair. If MCC did display data, then it was known that the communication lines were intact. All electronics from each station were brought into the lab for troubleshooting. Troubleshooting usually consisted of connecting an oscilloscope or scaler (Ortec model 871 or 775) at different points in the circuit of each detector to record simulated pulses produced by a pulse generator; the input and output pulses were compared to establish the location of any problems in the circuit. Once any problems were isolated, repairs were done accordingly. The detectors and electronics were then calibrated in the field using radioactive sources. Calibration is a process that determines the response of the detector. Detector response is defined as the ratio of the number of counts per minute interpreted by the detector to the amount of dose equivalent rate (in mrem per hour, either calculated or measured). Detector response for both detectors is dependent upon the energy of the incident radiation; this trend had to be accounted for in the calibration of the BF{sub 3} detector. Energy dependence did not have to be taken into consideration when calibrating the GM detectors since GM detector response is only dependent on radiation energy below 100 keV; SLAC only produces a spectrum of gamma radiation above 100 keV. For the GM detector, calibration consisted of bringing a {sup 137}Cs source and a NIST-calibrated RADCAL Radiation Monitor Controller (model 9010) out to the field; the absolute dose rate was determined by the RADCAL device while simultaneously irradiating the GM detector to obtain a scaler reading corresponding to counts per minute. Detector response was then calculated. Calibration of the BF{sub 3} detector was done using NIST certified neutron sources of known emission rates and energies. Five neutron sources ({sup 238}PuBe, {sup 238}PuB, {sup 238}PuF4, {sup 238}PuLi and {sup 252}Cf) with different energies were used to account for the energy dependence of the response. The actual neutron dose rate was calculated by date-correcting NIST source data and considering the direct dose rate and scattered dose rate. Once the total dose rate (sum of the direct and scattered dose rates) was known, the response vs. energy curve was plotted. The first station calibrated (PMS6) was calibrated with these five neutron sources; all subsequent stations were calibrated with one neutron source and the energy dependence was assumed to be the same.« less

10 CFR 39.77 - Notification of incidents and lost sources; abandonment procedures for irretrievable sources.

Code of Federal Regulations, 2013 CFR

2013-01-01

..., radiation overexposures, excessive levels and concentrations of radiation, and certain other accidents as... RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Security, Records, Notifications § 39.77 Notification of...

10 CFR 39.77 - Notification of incidents and lost sources; abandonment procedures for irretrievable sources.

Code of Federal Regulations, 2012 CFR

2012-01-01

..., radiation overexposures, excessive levels and concentrations of radiation, and certain other accidents as... RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Security, Records, Notifications § 39.77 Notification of...

10 CFR 39.77 - Notification of incidents and lost sources; abandonment procedures for irretrievable sources.

Code of Federal Regulations, 2011 CFR

2011-01-01

..., radiation overexposures, excessive levels and concentrations of radiation, and certain other accidents as... RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Security, Records, Notifications § 39.77 Notification of...

10 CFR 39.77 - Notification of incidents and lost sources; abandonment procedures for irretrievable sources.

Code of Federal Regulations, 2010 CFR

2010-01-01

..., radiation overexposures, excessive levels and concentrations of radiation, and certain other accidents as... RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Security, Records, Notifications § 39.77 Notification of...

10 CFR 39.77 - Notification of incidents and lost sources; abandonment procedures for irretrievable sources.

Code of Federal Regulations, 2014 CFR

2014-01-01

..., radiation overexposures, excessive levels and concentrations of radiation, and certain other accidents as... RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Security, Records, Notifications § 39.77 Notification of...

MO-G-BRE-08: Taxonomy of Corrective Actions in Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sutlief, S; Brown, D

2014-06-15

Purpose: Various causal taxonomies have been developed for healthcare incidents and for radiation therapy in particular. The causal analysis of incidents leads to corrective actions which can also be organized into a taxonomy. Such a corrective action classification system would provide information about the situational context, the action type, and the leverage of the action in order to detect patterns in the corrective actions frequently employed in radiation therapy. It would also provide practical guidance to the radiation therapy community for determining the appropriateness and potential effectiveness of proposed corrective actions. Materials: A review of causal analysis reports and correctivemore » action plans was conducted using the following sources: US NRC medical event reports, IAEA reports, ROSIS submissions, US Veterans Health Administration reports, and singleincident report sources. The corrective actions presented in the published sources were then mapped onto four corrective action taxonomy prototypes: role-based, safety-context-based, responsibility-based, and hierarchy of hazard control. The resulting corrective action taxonomy was then validated through use of the published sources. Results: The responsibility-based taxonomy and hierarchy of hazard taxonomy provided more intuitive and sensible categories than the role-based taxonomy or the safety-context taxonomy. The most frequent corrective actions were added safety barriers, training, process standardization, and development of a quality improvement program where one was lacking. Conclusion: Published corrective action statements in radiation therapy emphasize what to do more so than whom the recipient is or which process step is affected. The hierarchy of hazard taxonomy provides a suitable framework for radiation therapy and has the advantage of providing insight into the likelihood that a particular corrective action will mitigate the recurrence of the error it was meant to correct. This information would be useful to medical center administration, safety personnel, and regulators who must assess the projected efficacy of corrective actions. Derek Brown is a director of TreatSafely, LLC.« less

Alpha-ray spectrometry at high temperature by using a compound semiconductor detector.

PubMed

Ha, Jang Ho; Kim, Han Soo

2013-11-01

The use of conventional radiation detectors in harsh environments is limited by radiation damage to detector materials and by temperature constraints. We fabricated a wide-band gap semiconductor radiation detector based on silicon carbide. All the detector components were considered for an application in a high temperature environment like a nuclear reactor core. The radiation response, especially to alpha particles, was measured using an (241)Am source at variable operating voltages at room temperature in the air. The temperature on detector was controlled from 30°C to 250°C. The alpha-particle spectra were measured at zero bias operation. Even though the detector is operated at high temperature, the energy resolution as a function of temperature is almost constant within 3.5% deviation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Laser-plasma-based Space Radiation Reproduction in the Laboratory

PubMed Central

Hidding, B.; Karger, O.; Königstein, T.; Pretzler, G.; Manahan, G. G.; McKenna, P.; Gray, R.; Wilson, R.; Wiggins, S. M.; Welsh, G. H.; Beaton, A.; Delinikolas, P.; Jaroszynski, D. A.; Rosenzweig, J. B.; Karmakar, A.; Ferlet-Cavrois, V.; Costantino, A.; Muschitiello, M.; Daly, E.

2017-01-01

Space radiation is a great danger to electronics and astronauts onboard space vessels. The spectral flux of space electrons, protons and ions for example in the radiation belts is inherently broadband, but this is a feature hard to mimic with conventional radiation sources. Using laser-plasma-accelerators, we reproduced relativistic, broadband radiation belt flux in the laboratory, and used this man-made space radiation to test the radiation hardness of space electronics. Such close mimicking of space radiation in the lab builds on the inherent ability of laser-plasma-accelerators to directly produce broadband Maxwellian-type particle flux, akin to conditions in space. In combination with the established sources, utilisation of the growing number of ever more potent laser-plasma-accelerator facilities worldwide as complementary space radiation sources can help alleviate the shortage of available beamtime and may allow for development of advanced test procedures, paving the way towards higher reliability of space missions. PMID:28176862

Accelerator-based validation of shielding codes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeitlin, Cary; Heilbronn, Lawrence; Miller, Jack

2002-08-12

The space radiation environment poses risks to astronaut health from a diverse set of sources, ranging from low-energy protons and electrons to highly-charged, high-energy atomic nuclei and their associated fragmentation products, including neutrons. The low-energy protons and electrons are the source of most of the radiation dose to Shuttle and ISS crews, while the more energetic particles that comprise the Galactic Cosmic Radiation (protons, He, and heavier nuclei up to Fe) will be the dominant source for crews on long-duration missions outside the earth's magnetic field. Because of this diversity of sources, a broad ground-based experimental effort is required tomore » validate the transport and shielding calculations used to predict doses and dose-equivalents under various mission scenarios. The experimental program of the LBNL group, described here, focuses principally on measurements of charged particle and neutron production in high-energy heavy-ion fragmentation. Other aspects of the program include measurements of the shielding provided by candidate spacesuit materials against low-energy protons (particularly relevant to extra-vehicular activities in low-earth orbit), and the depth-dose relations in tissue for higher-energy protons. The heavy-ion experiments are performed at the Brookhaven National Laboratory's Alternating Gradient Synchrotron and the Heavy-Ion Medical Accelerator in Chiba in Japan. Proton experiments are performed at the Lawrence Berkeley National Laboratory's 88'' Cyclotron with a 55 MeV beam, and at the Loma Linda University Proton Facility with 100 to 250 MeV beam energies. The experimental results are an important component of the overall shielding program, as they allow for simple, well-controlled tests of the models developed to handle the more complex radiation environment in space.« less

Diffraction spectral filter for use in extreme-UV lithography condenser

DOEpatents

Sweatt, William C.; Tichenor, Daniel A.; Bernardez, Luis J.

2002-01-01

A condenser system for generating a beam of radiation includes a source of radiation light that generates a continuous spectrum of radiation light; a condenser comprising one or more first optical elements for collecting radiation from the source of radiation light and for generating a beam of radiation; and a diffractive spectral filter for separating first radiation light having a particular wavelength from the continuous spectrum of radiation light. Cooling devices can be employed to remove heat generated. The condenser system can be used with a ringfield camera in projection lithography.

Radiation-induced synthesis of poly(acrylic acid) nanogels

NASA Astrophysics Data System (ADS)

Matusiak, Malgorzata; Kadlubowski, Slawomir; Ulanski, Piotr

2018-01-01

Nanogel is a two-component system of a diameter in the range of tens of nanometers, consisting of an intramolecularly crosslinked polymer chain and solvent, typically water, filling the space between segments of the macromolecule. Microgels are bigger than nanogels and their size range is between 100 nm to 100 μm. One of the methods used for synthesizing nanogels is linking the segments of a single macromolecule with the use of ionizing radiation, by intramolecular recombination of radiation-generated polymer radicals. The main advantage of this technique is absence of monomers, catalysts, surfactants or crosslinking agents. This method is an interesting alternative way of synthesizing polymeric carriers for biomedical applications. The aim of the study was radiation synthesis and characterization of poly(acrylic acid) - PAA - nanogels and microgels. The physico-chemical properties were described by determination of weight-average molecular weight and dimensions (radius of gyration, hydrodynamic radius) of the nanogels and microgels. Influence of polymer concentration and dose on these parameters was analyzed. Adjusting the PAA concentration and absorbed dose, one can control the molecular weight and dimensions of nanogels. The solutions of PAA were irradiated with two sources of ionizing radiation: γ-source and electron accelerator. The former method yields mainly microgels due to prevailing intermolecular crosslinking, while the latter promotes intramolecular recombination of PAA-derived radicals and in consequence formation of nanogels. In the future radiation-synthesized PAA nanogels, after functionalization, will be tested as carriers for delivering radionuclides to the tumor cells.

Small unmanned aircraft system for remote contour mapping of a nuclear radiation field

NASA Astrophysics Data System (ADS)

Guss, Paul; McCall, Karen; Malchow, Russell; Fischer, Rick; Lukens, Michael; Adan, Mark; Park, Ki; Abbott, Roy; Howard, Michael; Wagner, Eric; Trainham, Clifford P.; Luke, Tanushree; Mukhopadhyay, Sanjoy; Oh, Paul; Brahmbhatt, Pareshkumar; Henderson, Eric; Han, Jinlu; Huang, Justin; Huang, Casey; Daniels, Jon

2017-09-01

For nuclear disasters involving radioactive contamination, small unmanned aircraft systems (sUASs) equipped with nuclear radiation detection and monitoring capability can be very important tools. Among the advantages of a sUAS are quick deployment, low-altitude flying that enhances sensitivity, wide area coverage, no radiation exposure health safety restriction, and the ability to access highly hazardous or radioactive areas. Additionally, the sUAS can be configured with the nuclear detecting sensor optimized to measure the radiation associated with the event. In this investigation, sUAS platforms were obtained for the installation of sensor payloads for radiation detection and electro-optical systems that were specifically developed for sUAS research, development, and operational testing. The sensor payloads were optimized for the contour mapping of a nuclear radiation field, which will result in a formula for low-cost sUAS platform operations with built-in formation flight control. Additional emphases of the investigation were to develop the relevant contouring algorithms; initiate the sUAS comprehensive testing using the Unmanned Systems, Inc. (USI) Sandstorm platforms and other acquired platforms; and both acquire and optimize the sensors for detection and localization. We demonstrated contour mapping through simulation and validated waypoint detection. We mounted a detector on a sUAS and operated it initially in the counts per second (cps) mode to perform field and flight tests to demonstrate that the equipment was functioning as designed. We performed ground truth measurements to determine the response of the detector as a function of source-to-detector distance. Operation of the radiation detector was tested using different unshielded sources.

High-Field High-Repetition-Rate Sources for the Coherent THz Control of Matter

PubMed Central

Green, B.; Kovalev, S.; Asgekar, V.; Geloni, G.; Lehnert, U.; Golz, T.; Kuntzsch, M.; Bauer, C.; Hauser, J.; Voigtlaender, J.; Wustmann, B.; Koesterke, I.; Schwarz, M.; Freitag, M.; Arnold, A.; Teichert, J.; Justus, M.; Seidel, W.; Ilgner, C.; Awari, N.; Nicoletti, D.; Kaiser, S.; Laplace, Y.; Rajasekaran, S.; Zhang, L.; Winnerl, S.; Schneider, H.; Schay, G.; Lorincz, I.; Rauscher, A. A.; Radu, I.; Mährlein, S.; Kim, T. H.; Lee, J. S.; Kampfrath, T.; Wall, S.; Heberle, J.; Malnasi-Csizmadia, A.; Steiger, A.; Müller, A. S.; Helm, M.; Schramm, U.; Cowan, T.; Michel, P.; Cavalleri, A.; Fisher, A. S.; Stojanovic, N.; Gensch, M.

2016-01-01

Ultrashort flashes of THz light with low photon energies of a few meV, but strong electric or magnetic field transients have recently been employed to prepare various fascinating nonequilibrium states in matter. Here we present a new class of sources based on superradiant enhancement of radiation from relativistic electron bunches in a compact electron accelerator that we believe will revolutionize experiments in this field. Our prototype source generates high-field THz pulses at unprecedented quasi-continuous-wave repetition rates up to the MHz regime. We demonstrate parameters that exceed state-of-the-art laser-based sources by more than 2 orders of magnitude. The peak fields and the repetition rates are highly scalable and once fully operational this type of sources will routinely provide 1 MV/cm electric fields and 0.3 T magnetic fields at repetition rates of few 100 kHz. We benchmark the unique properties by performing a resonant coherent THz control experiment with few 10 fs resolution. PMID:26924651

High-Field High-Repetition-Rate Sources for the Coherent THz Control of Matter

DOE PAGES

Green, B.; Kovalev, S.; Asgekar, V.; ...

2016-02-29

Ultrashort flashes of THz light with low photon energies of a few meV, but strong electric or magnetic field transients have recently been employed to prepare various fascinating nonequilibrium states in matter. Here we present a new class of sources based on superradiant enhancement of radiation from relativistic electron bunches in a compact electron accelerator that we believe will revolutionize experiments in this field. Our prototype source generates high-field THz pulses at unprecedented quasi-continuous-wave repetition rates up to the MHz regime. We demonstrate parameters that exceed state-of-the-art laser-based sources by more than 2 orders of magnitude. The peak fields andmore » the repetition rates are highly scalable and once fully operational this type of sources will routinely provide 1 MV/cm electric fields and 0.3 T magnetic fields at repetition rates of few 100 kHz. In conclusion, we benchmark the unique properties by performing a resonant coherent THz control experiment with few 10 fs resolution.« less

Acoustic centering of sources measured by surrounding spherical microphone arrays.

PubMed

Hagai, Ilan Ben; Pollow, Martin; Vorländer, Michael; Rafaely, Boaz

2011-10-01

The radiation patterns of acoustic sources have great significance in a wide range of applications, such as measuring the directivity of loudspeakers and investigating the radiation of musical instruments for auralization. Recently, surrounding spherical microphone arrays have been studied for sound field analysis, facilitating measurement of the pressure around a sphere and the computation of the spherical harmonics spectrum of the sound source. However, the sound radiation pattern may be affected by the location of the source inside the microphone array, which is an undesirable property when aiming to characterize source radiation in a unique manner. This paper presents a theoretical analysis of the spherical harmonics spectrum of spatially translated sources and defines four measures for the misalignment of the acoustic center of a radiating source. Optimization is used to promote optimal alignment based on the proposed measures and the errors caused by numerical and array-order limitations are investigated. This methodology is examined using both simulated and experimental data in order to investigate the performance and limitations of the different alignment methods. © 2011 Acoustical Society of America

Effect of inflow control on inlet noise of a cut-on fan. [in an anechoic chamber

NASA Technical Reports Server (NTRS)

Woodward, R. P.; Glaser, F. W.

1980-01-01

The control of turbulence and other inflow disturbances in anechoic chambers for static turbofan noise studies was studied. A cut-on, high tip speed fan stage was acoustically tested with three configurations of an inflow control device in an anechoic chamber. Although this was a cut-on design, rotor inflow interaction appeared to be a much stronger source of blade passing tone radiated from the inlet than rotor stator interaction for the 1.6 mean rotor chord separation. Aft external suction applied to the area where the inflow control device joined the inlet produced a further reduction in blade passing tone, suggesting that disturbances in the forward flow on the outside of the inlet were superimposed on the inlet boundary layer and were a significant source of tone noise.

Systems, Apparatuses and Methods for Beamforming RFID Tags

NASA Technical Reports Server (NTRS)

Fink, Patrick W. (Inventor); Lin, Gregory Y. (Inventor); Ngo, Phong H. (Inventor); Kennedy, Timothy F. (Inventor)

2017-01-01

A radio frequency identification (RFID) system includes an RFID interrogator and an RFID tag having a plurality of information sources and a beamforming network. The tag receives electromagnetic radiation from the interrogator. The beamforming network directs the received electromagnetic radiation to a subset of the plurality of information sources. The RFID tag transmits a response to the received electromagnetic radiation, based on the subset of the plurality of information sources to which the received electromagnetic radiation was directed. Method and other embodiments are also disclosed.

Effect of radiation on female Ae. aegypti pupae for SIT

USDA-ARS?s Scientific Manuscript database

Aedes aegypti is a vector mosquito that can transmit pathogens that can cause disease in humans and animals. However, it is difficult to control them through larvicides and/or source reduction because they can develop in a wide range of water holding containers. One method that has been explored is ...

The rotary subwoofer: a controllable infrasound source.

PubMed

Park, Joseph; Garcés, Milton; Thigpen, Bruce

2009-04-01

The rotary subwoofer is a novel acoustic transducer capable of projecting infrasonic signals at high sound pressure levels. The projector produces higher acoustic particle velocities than conventional transducers which translate into higher radiated sound pressure levels. This paper characterizes measured performance of a rotary subwoofer and presents a model to predict sound pressure levels.

Tomographic gamma ray apparatus and method

DOEpatents

Anger, Hal O.

1976-09-07

This invention provides a radiation detecting apparatus for imaging the distribution of radioactive substances in a three-dimensional subject such as a medical patient. Radiating substances introduced into the subject are viewed by a radiation image detector that provides an image of the distribution of radiating sources within its field of view. By viewing the area of interest from two or more positions, as by scanning the detector over the area, the radiating sources seen by the detector have relative positions that are a function of their depth in the subject. The images seen by the detector are transformed into first output signals which are combined in a readout device with second output signals that indicate the position of the detector relative to the subject. The readout device adjusts the signals and provides multiple radiation distribution readouts of the subject, each readout comprising a sharply resolved picture that shows the distribution and intensity of radiating sources lying in a selected plane in the subject, while sources lying on other planes are blurred in that particular readout.

Observation of microwave absorption and emission from incoherent electron tunneling through a normal-metal-insulator-superconductor junction.

PubMed

Masuda, Shumpei; Tan, Kuan Y; Partanen, Matti; Lake, Russell E; Govenius, Joonas; Silveri, Matti; Grabert, Hermann; Möttönen, Mikko

2018-03-02

We experimentally study nanoscale normal-metal-insulator-superconductor junctions coupled to a superconducting microwave resonator. We observe that bias-voltage-controllable single-electron tunneling through the junctions gives rise to a direct conversion between the electrostatic energy and that of microwave photons. The measured power spectral density of the microwave radiation emitted by the resonator exceeds at high bias voltages that of an equivalent single-mode radiation source at 2.5 K although the phonon and electron reservoirs are at subkelvin temperatures. Measurements of the generated power quantitatively agree with a theoretical model in a wide range of bias voltages. Thus, we have developed a microwave source which is compatible with low-temperature electronics and offers convenient in-situ electrical control of the incoherent photon emission rate with a predetermined frequency, without relying on intrinsic voltage fluctuations of heated normal-metal components or suffering from unwanted losses in room temperature cables. Importantly, our observation of negative generated power at relatively low bias voltages provides a novel type of verification of the working principles of the recently discovered quantum-circuit refrigerator.

Centring radiological protection on today's global challenges in energy, climate change, environment and health--with nuclear energy playing a key role.

PubMed

Saint-Pierre, Sylvain

2011-07-01

The climate change issue includes meeting the growing demand for electricity while reducing the impacts from energy sources. Applying carbon capture and storage technology to fossil fuel energy and increasing renewable energy pose greater challenges than increasing nuclear energy. International Energy Agency's (IEA) electricity demand of 30 000 TWh by 2030 can be met with 10 000 TWh each from renewable, nuclear and fossil fuel energy. However, the ill-imposed very strict control of tiny public exposure to ionising radiation from nuclear energy continues to pose a serious hindrance. Effort needs to be re-balanced to produce an even-handed control of public exposure with emphasis on the most significant sources (i.e. natural background radiation and medical use) and vice versa. The on-going revision of the International Atomic Energy Agency Basic Safety Standards (BSS) provides an opportunity to achieve this internationally so that national regulations can be subsequently remediated. There can be no urgency in a BSS revision that fails to encompass such perspective.

Radar detection of radiation-induced ionization in air

DOEpatents

Gopalsami, Nachappa; Heifetz, Alexander; Chien, Hual-Te; Liao, Shaolin; Koehl, Eugene R.; Raptis, Apostolos C.

2015-07-21

A millimeter wave measurement system has been developed for remote detection of airborne nuclear radiation, based on electromagnetic scattering from radiation-induced ionization in air. Specifically, methods of monitoring radiation-induced ionization of air have been investigated, and the ionized air has been identified as a source of millimeter wave radar reflection, which can be utilized to determine the size and strength of a radiation source.

Critical radiation fluxes and luminosities of black holes and relativistic stars

NASA Technical Reports Server (NTRS)

Lamb, Frederick K.; Miller, M. Coleman

1995-01-01

The critial luminosity at which the outward force of radiation balances the inward force of gravity plays an important role in many astrophysical systems. We present expressions for the radiation force on particles with arbitrary cross sections and analyze the radiation field produced by radiating matter, such as a disk, ring, boundary layer, or stellar surface, that rotates slowly around a slowly rotating gravitating mass. We then use these results to investigate the critical radiation flux and, where possible, the critical luminosity of such a system in genral relativity. We demonstrate that if the radiation source is axisymmetric and emission is back-front symmetric with repect to the local direction of motion of the radiating matter, as seen in the comoving frame, then the radial component of the radiation flux and the diagonal components of the radiation stress-energy tensor outside the source are the same, to first order in the rotation rates, as they would be if the radiation source and gravitating mass were not rotating. We argue that the critical radiation flux for matter at rest in the locally nonrotating frame is often satisfactory as an astrophysical benchmark flux and show that if this benchmark is adopted, many of the complications potentially introduced by rotation of the radiation source and the gravitating mass are avoided. We show that if the radiation field in the absence of rotation would be spherically symmetric and the opacity is independent of frequency and direction, one can define a critical luminosity for the system that is independent of frequency and direction, one can define a critical luminosity for the system that is independent of the spectrum and angular size of the radiation source and is unaffected by rotation of the source and mass and orbital motion of the matter, to first order. Finally, we analyze the conditions under which the maximum possible luminosity of a star or black hole powered by steady spherically symmetric radial accretion is the same in general relativity as in the Newtonian limit.

Optical Imaging of Ionizing Radiation from Clinical Sources.

PubMed

Shaffer, Travis M; Drain, Charles Michael; Grimm, Jan

2016-11-01

Nuclear medicine uses ionizing radiation for both in vivo diagnosis and therapy. Ionizing radiation comes from a variety of sources, including x-rays, beam therapy, brachytherapy, and various injected radionuclides. Although PET and SPECT remain clinical mainstays, optical readouts of ionizing radiation offer numerous benefits and complement these standard techniques. Furthermore, for ionizing radiation sources that cannot be imaged using these standard techniques, optical imaging offers a unique imaging alternative. This article reviews optical imaging of both radionuclide- and beam-based ionizing radiation from high-energy photons and charged particles through mechanisms including radioluminescence, Cerenkov luminescence, and scintillation. Therapeutically, these visible photons have been combined with photodynamic therapeutic agents preclinically for increasing therapeutic response at depths difficult to reach with external light sources. Last, new microscopy methods that allow single-cell optical imaging of radionuclides are reviewed. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

A new storage-ring light source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chao, Alex

2015-06-01

A recently proposed technique in storage ring accelerators is applied to provide potential high-power sources of photon radiation. The technique is based on the steady-state microbunching (SSMB) mechanism. As examples of this application, one may consider a high-power DUV photon source for research in atomic and molecular physics or a high-power EUV radiation source for industrial lithography. A less challenging proof-of-principle test to produce IR radiation using an existing storage ring is also considered.

External beam ionizing radiation for inhibition of myointimal hyperplasia after dilatation and anastomoses: experimental models and results.

PubMed

Ducasse, Eric; Cosset, Jean-Marc; Eschwege, François; Creusy, Colette; Chevalier, Jacques; Puppinck, Paul; Lartigau, Eric

2004-01-01

In recent years there has been intensive research on the use of ionizing radiation for inhibition of intimal hyperplasia (IH). Results have clearly established that beta ionizing radiation delivered from an endoluminal source after angioplasty inhibits intimal restenosis. This effect has been confirmed by recent multicenter clinical trials in patients undergoing coronary dilatation. The purpose of this study was to determine if gamma radiation therapy delivered superficially from an external source also reduced smooth muscle cell proliferation in two animals models-the first involving experimentally induced restenosis and the second involving anastomosis between a prosthesis and artery. Ultimately we hope to develop a therapeutic application for patients undergoing peripheral anastomoses, especially in the lower extremities. Two different animal models were used in this two-stage study. The first-stage rabbit model (model 1) involved balloon injury of the aorta to validate the dose effect of external beam irradiation. The second-stage porcine model (model 2) involved aortic bypass followed by external beam irradiation of the distal anastomosis site. In model 1 a total of 56 rabbits were studied. They were divided into five groups including one control group in which external radiation was not applied after balloon injury and four test groups in which external radiation was applied in a single fraction on day 0 at four different doses: 10 grays, 15 grays, 20 grays, and 25 grays. In model 2, a total of 24 pigs underwent aortic bypass with a 6-mm PTFE graft followed by irradiation of the distal end-to-side anastomosis at a dose of 20 grays on day 0. In both models specimens were harvested after 6 weeks and studied histologically after staining with HES and orcein, histomorphometrically by measuring intimal hyperplasia, and immunohistochemically using actin and factor VIII/von Willebrand factor (F VIII/vWF). The zones of study on the anastomosis were separated into base of the artery to the tip and heel of the anastomosis and the edge of the arteriotomy. Measurements were compared using the Mann Whitney test. In the first-stage model designed to study IH in rabbits, mean intimal and medial thickness values and the intima-to-media ratio showed no difference between the control group and the groups irradiated at doses of 10 grays and 15 grays (p = 0.111, p = 0.405, and p = 0.14); (p = 0.301, p = 0.206, and p = 0.199). Conversely, there was a significant difference between the control group and the groups irradiated at 20 grays and 25 grays (p < 0.0001, p = 0.107 and p = 0.008; p = 0.008, p = 0.155, and p = 0.008). Histological examination demonstrated extensive changes in the wall with high-grade fibrosis after application of ionizing radiation. In the second-stage swine model, irradiation significantly inhibited development of IH at the level of anastomosis both at the base of the artery (p < 0.01) (tip 0.06 vs. 0.27 mm and heel 0.04 vs. 0.36) and at the level of the arteriotomy at the suture site (p < 0.001) (0.13 vs. 0.86 mm). Immunochemical analysis of the thickened zones showed a positive reaction of endothelial cells to smooth muscle actin and F VII/vWF. Like irradiation applied using an endoluminal source, superficial gamma ionizing radiation from an external source inhibits IH. Analysis of the dose effect showed that the overall dose must be between 15 and 20 grays. External radiation also reduces overall IH at the anastomosis between a prosthesis and artery. Although these experimental data are promising, further study will probably be necessary before attempting to undertake clinical trials using external beam radiation therapy for patients undergoing peripheral anastomoses.

An Evaluation of a Passively Cooled Cylindrical Spectrometer Array in Lunar Orbit

NASA Technical Reports Server (NTRS)

Waggoner, Jason

2014-01-01

This thesis will evaluate a passively cooled cylindrical spectrometer array in lunar orbit characterizing the thermal response in order to provide context for decision-making to scientists and engineers. To provide perspective on thermal issues and controls of space science instruments, a background search of historical lunar missions is provided. Next, a trial science mission is designed and analyzed which brings together the elements of the background search, lunar orbit environment and passive cooling. Finally, the trial science mission analysis results are provided along with the conclusions drawn. Scintillators are materials that when struck by particle radiation, absorb the particle energy which is then reemitted as light in or near the visible range. Nuclear astrophysics utilizes scintillating materials for observation of high-energy photons which are generated by sources such as solar flares, supernovae and neutron stars. SPMs are paired with inorganic scintillators to detect the light emitted which is converted into electronic signals. The signals are captured and analyzed in order to map the number and location of the high-energy sources. The SPM is utilized as it has single photon sensitivity, low voltage requirements and a fast response. SPMs are also compact, relatively inexpensive and allow the usage of lower-cost scintillating materials within the spectrometer. These characteristics permit large-area arrays while lowering cost and power requirements. The ability of a spectrometer to record and identify the interaction of high-energy photons for scientific return is not a trivial matter. Background noise is generated when particles that have not originated from the desired distant source impact the spectrometer. Additionally, thermally induced electrical signals are randomly generated within the SPM even in the absence of light which is referred to as dark current. Overcoming these obstacles requires greater light emittance and energy resolution with reduced dark current. Strong scintillation photon emittance ensures that low energy impacts will produce enough visible photons to be detected by the SPM. Higher energy resolution will ensure that single photon impacts can be distinguished from others of similar wavelength and energy; reduced dark current decreases the generation of random signals not associated with a photon impact. Increasing efficiency in each of these properties in a spectrometer comprised of inorganic scintillators and SPMs requires low temperatures. Low temperature maintenance in a lunar environment presents many unique challenges of its own. Even with the accumulated successes of past missions, the lunar environment remains a thermal challenge for engineers. The lunar orbit thermal environment is driven by radiation from three sources, direct solar radiation, reflected solar radiation from the lunar surface (albedo) and lunar radiation (Clawson 2002). Direct solar radiation values are consistent with those seen in Earth orbit (1325 W/m2) (Clawson 2002). The percentage of solar radiation reflected from the moon is consistently very low with the moon's dark regolith covered surface absorbing nearly 90% of the incident light (Clawson 2002). Yet, it is this absorption that gives the lunar orbit environment one of its most difficult thermal attributes as the absorbed solar radiation is released from the lunar surface as infrared radiation (IR). IR is of a wavelength that is readily absorbed by surfaces designed to function as radiation emitters. It is practical to therefore "choose radiator locations and spacecraft attitude to minimize radiator views to the lunar surface, when possible...pointing the radiator towards the sun to some extent, to minimize its view to the lunar surface, is frequently preferable. (Clawson 2002)" Additionally, the amount of direct solar radiation, lunar IR and albedo an orbiting satellite receives varies from one side of the moon to the other as the moon blocks the sun from view. This environment produces large temperature variations in a satellite's instrumentation, control electronics and propulsion systems which must be understood to characterize operating temperature envelopes.

A generalized theory on the noise generation from supersonic shear layers.

NASA Technical Reports Server (NTRS)

Pao, S. P.

1971-01-01

A generalization is presented of Phillips' (1960) theory of noise generation by supersonic turbulent shear layers. Both Mach wave radiation and non-Mach wave noise radiation mechanisms are considered. The range of validity of Phillips' theory has been expanded to include the low supersonic and transonic ranges. These generalizations are important not only for their analytical rigor, but also for their prospective applications to practical problems in jet noise prediction and control. The noise generation mechanisms in a supersonic jet are found to differ from those in a subsonic jet. The theory is considered to offer some prospects of answering important questions in supersonic jet noise, such as noise source distribution, mean flow refraction effects, directivity, spectrum, and efficiency of noise radiation.

Impurity mixing and radiation asymmetry in massive gas injection simulations of DIII-D

DOE Office of Scientific and Technical Information (OSTI.GOV)

Izzo, V. A.

Simulations of neon massive gas injection into DIII-D are performed with the 3D MHD code NIMROD. The poloidal and toroidal distribution of the impurity source is varied. This report will focus on the effects of the source variation on impurity mixing and radiated power asymmetry. Even toroidally symmetric impurity injection is found to produce asymmetric radiated power due to asymmetric convective heat flux produced by the 1/1 mode. When the gas source is toroidally localized, the phase relationship between the mode and the source location is important, affecting both radiation peaking and impurity mixing. Under certain circumstances, a single, localizedmore » gas jet could produce better radiation symmetry during the disruption thermal quench than evenly distributed impurities.« less

Analysis of space reactor system components: Investigation through simulation and non-nuclear testing

NASA Astrophysics Data System (ADS)

Bragg-Sitton, Shannon M.

The use of fission energy in space power and propulsion systems offers considerable advantages over chemical propulsion. Fission provides over six orders of magnitude higher energy density, which translates to higher vehicle specific impulse and lower specific mass. These characteristics enable ambitious space exploration missions. The natural space radiation environment provides an external source of protons and high energy, high Z particles that can result in the production of secondary neutrons through interactions in reactor structures. Applying the approximate proton source in geosynchronous orbit during a solar particle event, investigation using MCNPX 2.5.b for proton transport through the SAFE-400 heat pipe cooled reactor indicates an incoming secondary neutron current of (1.16 +/- 0.03) x 107 n/s at the core-reflector interface. This neutron current may affect reactor operation during low power maneuvers (e.g., start-up) and may provide a sufficient reactor start-up source. It is important that a reactor control system be designed to automatically adjust to changes in reactor power levels, maintaining nominal operation without user intervention. A robust, autonomous control system is developed and analyzed for application during reactor start-up, accounting for fluctuations in the radiation environment that result from changes in vehicle location or to temporal variations in the radiation field. Development of a nuclear reactor for space applications requires a significant amount of testing prior to deployment of a flight unit. High confidence in fission system performance can be obtained through relatively inexpensive non-nuclear tests performed in relevant environments, with the heat from nuclear fission simulated using electric resistance heaters. A series of non-nuclear experiments was performed to characterize various aspects of reactor operation. This work includes measurement of reactor core deformation due to material thermal expansion and implementation of a virtual reactivity feedback control loop; testing and thermal hydraulic characterization of the coolant flow paths for two space reactor concepts; and analysis of heat pipe operation during start-up and steady state operation.

Optimum Water Chemistry in radiation field buildup control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Chien, C.

1995-03-01

Nuclear utilities continue to face the challenGE of reducing exposure of plant maintenance personnel. GE Nuclear Energy has developed the concept of Optimum Water Chemistry (OWC) to reduce the radiation field buildup and minimize the radioactive waste production. It is believed that reduction of radioactive sources and improvement of the water chemistry quality should significantly reduce both the radiation exposure and radwaste production. The most important source of radioactivity is cobalt and replacement of cobalt containing alloy in the core region as well as in the entire primary system is considered the first priority to achieve the goal of lowmore » exposure and minimized waste production. A plant specific computerized cobalt transport model has been developed to evaluate various options in a BWR system under specific conditions. Reduction of iron input and maintaining low ionic impurities in the coolant have been identified as two major tasks for operators. Addition of depleted zinc is a proven technique to reduce Co-60 in reactor water and on out-of-core piping surfaces. The effect of HWC on Co-60 transport in the primary system will also be discussed.« less

Selective THz control of magnetic order: new opportunities from superradiant undulator sources

NASA Astrophysics Data System (ADS)

Kovalev, S.; Wang, Zhe; Deinert, J.-C.; Awari, N.; Chen, M.; Green, B.; Germanskiy, S.; de Oliveira, T. V. A. G.; Lee, J. S.; Deac, A.; Turchinovich, D.; Stojanovic, N.; Eisebitt, S.; Radu, I.; Bonetti, S.; Kampfrath, T.; Gensch, M.

2018-03-01

Recent advancements of accelerator technology enable the generation of carrier-envelope-phase stable THz pulses with high fields at adjustable high repetition rates. The appropriate choice of THz radiator allows generation of narrow-band, spectrally dense, multicycle THz transients of tunable THz frequency which are ideally suited to selectively excite low-energy excitations such as magnons or phonons. They also allow one to study the frequency dependence of nonresonant THz-field interactions with various order parameters with high dynamic range. In this paper, we discuss the future prospects of this new type of THz light source for studying the coherent control of magnetic order based on recent results.

Atmospheric State, Cloud Microphysics and Radiative Flux

DOE Data Explorer

Mace, Gerald

2008-01-15

Atmospheric thermodynamics, cloud properties, radiative fluxes and radiative heating rates for the ARM Southern Great Plains (SGP) site. The data represent a characterization of the physical state of the atmospheric column compiled on a five-minute temporal and 90m vertical grid. Sources for this information include raw measurements, cloud property and radiative retrievals, retrievals and derived variables from other third-party sources, and radiative calculations using the derived quantities.

Controlled-source seismic interferometry with one way wave fields

NASA Astrophysics Data System (ADS)

van der Neut, J.; Wapenaar, K.; Thorbecke, J. W.

2008-12-01

In Seismic Interferometry we generally cross-correlate registrations at two receiver locations and sum over an array of sources to retrieve a Green's function as if one of the receiver locations hosts a (virtual) source and the other receiver location hosts an actual receiver. One application of this concept is to redatum an area of surface sources to a downhole receiver location, without requiring information about the medium between the sources and receivers, thus providing an effective tool for imaging below complex overburden, which is also known as the Virtual Source method. We demonstrate how elastic wavefield decomposition can be effectively combined with controlled-source Seismic Interferometry to generate virtual sources in a downhole receiver array that radiate only down- or upgoing P- or S-waves with receivers sensing only down- or upgoing P- or S- waves. For this purpose we derive exact Green's matrix representations from a reciprocity theorem for decomposed wavefields. Required is the deployment of multi-component sources at the surface and multi- component receivers in a horizontal borehole. The theory is supported with a synthetic elastic model, where redatumed traces are compared with those of a directly modeled reflection response, generated by placing active sources at the virtual source locations and applying elastic wavefield decomposition on both source and receiver side.

Broad band waveguide spectrometer

DOEpatents

Goldman, Don S.

1995-01-01

A spectrometer for analyzing a sample of material utilizing a broad band source of electromagnetic radiation and a detector. The spectrometer employs a waveguide possessing an entry and an exit for the electromagnetic radiation emanating from the source. The waveguide further includes a surface between the entry and exit portions which permits interaction between the electromagnetic radiation passing through the wave guide and a sample material. A tapered portion forms a part of the entry of the wave guide and couples the electromagnetic radiation emanating from the source to the waveguide. The electromagnetic radiation passing from the exit of the waveguide is captured and directed to a detector for analysis.

Methyl halide fluxes from tropical plants under controlled radiation and temperature regimes

NASA Astrophysics Data System (ADS)

Blei, Emanuel; Yokouchi, Yoko; Saito, Takuya; Nozoe, Susumu

2015-04-01

Methyl halides (CH3Cl, CH3Br, CH3I) contribute significantly to the halogen burden of the atmosphere and have the potential to influence the stratospheric ozone layer through their catalytic effect in the Chapman cycle. As such they have been studied over the years, and many plants and biota have been examined for their potential to act as a source of these gases. One of the potentially largest terrestrial sources identified was tropical vegetation such as tropical ferns and Dipterocarp trees. Most of these studies concentrated on the identification and quantification of such fluxes rather than their characteristics and often the chambers used in these studies were either opaque or only partially transparent to the full solar spectrum. Therefore it is not certain to which degree emissions of methyl halides are innate to the plants and how much they might vary due to radiation or temperature conditions inside the enclosures. In a separate development it had been proposed that UV-radiation could cause live plant materials to be become emitters of methane even under non-anoxic conditions. As methane is chemically very similar to methyl halides and had been proposed to be produced from methyl-groups ubiquitously found in plant cell material there is a relatively good chance that such a production mechanism would also apply to methyl halides. To test whether radiation can affect elevated emissions of methyl halides from plant materials and to distinguish this from temperature effects caused by heat build-up in chambers a set of controlled laboratory chamber enclosures under various radiation and temperature regimes was conducted on four different tropical plant species (Magnolia grandiflora, Cinnamonum camphora, Cyathea lepifera, Angiopteris lygodiifolia), the latter two of which had previously been identified as strong methyl halide emitters. Abscised leaf samples of these species were subjected to radiation treatments such UV-B, UV-A and broad spectrum radiation similar to natural sunlight without the UV-component and the emissions were compared to dark enclosures. Parallel to this temperature effects were studied in dark enclosures as well. The presentation will discuss the outcome of these experiments and what conclusions can be drawn from them.

SYNCHROTRON RADIATION, FREE ELECTRON LASER, APPLICATION OF NUCLEAR TECHNOLOGY, ETC.: Study on the characteristics of linac based THz light source

NASA Astrophysics Data System (ADS)

Zhu, Xiong-Wei; Wang, Shu-Hong; Chen, Sen-Yu

2009-10-01

There are many methods based on linac for THz radiation production. As one of the options for the Beijing Advanced Light, an ERL test facility is proposed for THz radiation. In this test facility, there are 4 kinds of methods to produce THz radiation: coherent synchrotron radiation (CSR), synchrotron radiation (SR), low gain FEL oscillator, and high gain SASE FEL. In this paper, we study the characteristics of the 4 kinds of THz light sources.

Radiation Protection

MedlinePlus

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32 CFR 655.10 - Oversight of radiation sources brought on Army land by non-Army entities (AR 385-10).

Code of Federal Regulations, 2012 CFR

2012-07-01

... land by non-Army entities (AR 385-10). 655.10 Section 655.10 National Defense Department of Defense... Oversight of radiation sources brought on Army land by non-Army entities (AR 385-10). (a) As used in this... possession of ionizing radiation sources by non-Army entities (including their civilian contractors) on an...

32 CFR 655.10 - Oversight of radiation sources brought on Army land by non-Army entities (AR 385-10).

Code of Federal Regulations, 2011 CFR

2011-07-01

... land by non-Army entities (AR 385-10). 655.10 Section 655.10 National Defense Department of Defense... Oversight of radiation sources brought on Army land by non-Army entities (AR 385-10). (a) As used in this... possession of ionizing radiation sources by non-Army entities (including their civilian contractors) on an...

32 CFR 655.10 - Oversight of radiation sources brought on Army land by non-Army entities (AR 385-10).

Code of Federal Regulations, 2013 CFR

2013-07-01

... land by non-Army entities (AR 385-10). 655.10 Section 655.10 National Defense Department of Defense... Oversight of radiation sources brought on Army land by non-Army entities (AR 385-10). (a) As used in this... possession of ionizing radiation sources by non-Army entities (including their civilian contractors) on an...

32 CFR 655.10 - Oversight of radiation sources brought on Army land by non-Army entities (AR 385-10).

Code of Federal Regulations, 2014 CFR

2014-07-01

... land by non-Army entities (AR 385-10). 655.10 Section 655.10 National Defense Department of Defense... Oversight of radiation sources brought on Army land by non-Army entities (AR 385-10). (a) As used in this... possession of ionizing radiation sources by non-Army entities (including their civilian contractors) on an...

Reactor for simulation and acceleration of solar ultraviolet damage

NASA Technical Reports Server (NTRS)

Laue, E.; Gupta, A.

1979-01-01

An environmental test chamber providing acceleration of UV radiation and precise temperature control (+ or -)1 C was designed, constructed and tested. This chamber allows acceleration of solar ultraviolet up to 30 suns while maintaining temperature of the absorbing surface at 30 C - 60 C. This test chamber utilizes a filtered medium pressure mercury arc as the source of radiation, and a combination of selenium radiometer and silicon radiometer to monitor solar ultraviolet (295-340 nm) and total radiant power output, respectively. Details of design and construction and operational procedures are presented along with typical test data.

Efficient terahertz wave generation from GaP crystals pumped by chirp-controlled pulses from femtosecond photonic crystal fiber amplifier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Jiang; Shi, Junkai; Xu, Baozhong

2014-01-20

A chirp-tunable femtosecond 10 W, 42 MHz photonic-crystal-fiber oscillator-amplifier system that is capable of delivering sub-60 fs light pulses at 1040 nm is used to demonstrate high-efficiency terahertz radiation generation via optical rectification in GaP crystals only a few millimeters in length. The optimization of the chirp of the fiber-laser pulses is shown to radically enhance the terahertz output, indicating one possible way to more efficiently use these extended nonlinear crystals in compact fiber-pumped terahertz radiation sources.

International Standardization of the Clinical Dosimetry of Beta Radiation Brachytherapy Sources: Progress of an ISO Standard

NASA Astrophysics Data System (ADS)

Soares, Christopher

2006-03-01

In 2004 a new work item proposal (NWIP) was accepted by the International Organization for Standardization (ISO) Technical Committee 85 (TC85 -- Nuclear Energy), Subcommittee 2 (Radiation Protection) for the development of a standard for the clinical dosimetry of beta radiation sources used for brachytherapy. To develop this standard, a new Working Group (WG 22 - Ionizing Radiation Dosimetry and Protocols in Medical Applications) was formed. The standard is based on the work of an ad-hoc working group initiated by the Dosimetry task group of the Deutsches Insitiut für Normung (DIN). Initially the work was geared mainly towards the needs of intravascular brachytherapy, but with the decline of this application, more focus has been placed on the challenges of accurate dosimetry for the concave eye plaques used to treat ocular melanoma. Guidance is given for dosimetry formalisms, reference data to be used, calibrations, measurement methods, modeling, uncertainty determinations, treatment planning and reporting, and clinical quality control. The document is currently undergoing review by the ISO member bodies for acceptance as a Committee Draft (CD) with publication of the final standard expected by 2007. There are opportunities for other ISO standards for medical dosimetry within the framework of WG22.

Contextual Information for the Potential Enhancement of Annual Radiation Protection Program Review Reports.

PubMed

Emery, Robert J; Gutiérrez, Janet M

2017-08-01

Organizations possessing sources of ionizing radiation are required to develop, document, and implement a "radiation protection program" that is commensurate with the scope and extent of permitted activities and sufficient to ensure compliance with basic radiation safety regulations. The radiation protection program must also be reviewed at least annually, assessing program content and implementation. A convenience sample assessment of web-accessible and voluntarily-submitted radiation protection program annual review reports revealed that while the reports consistently documented compliance with necessary regulatory elements, very few included any critical contextual information describing how important the ability to possess radiation sources was to the central mission of the organization. Information regarding how much radioactive material was currently possessed as compared to license limits was also missing. Summarized here are suggested contextual elements that can be considered for possible inclusion in annual radiation protection program reviews to enhance stakeholder understanding and appreciation of the importance of the ability to possess radiation sources and the importance of maintaining compliance with associated regulatory requirements.

Radioactivity: A Natural Phenomenon.

ERIC Educational Resources Information Center

Ronneau, C.

1990-01-01

Discussed is misinformation people have on the subject of radiation. The importance of comparing artificial source levels of radiation to natural levels is emphasized. Measurements of radioactivity, its consequences, and comparisons between the risks induced by radiation in the environment and from artificial sources are included. (KR)

Modeling Urban Scenarios & Experiments: Fort Indiantown Gap Data Collections Summary and Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Archer, Daniel E.; Bandstra, Mark S.; Davidson, Gregory G.

This report summarizes experimental radiation detector, contextual sensor, weather, and global positioning system (GPS) data collected to inform and validate a comprehensive, operational radiation transport modeling framework to evaluate radiation detector system and algorithm performance. This framework will be used to study the influence of systematic effects (such as geometry, background activity, background variability, environmental shielding, etc.) on detector responses and algorithm performance using synthetic time series data. This work consists of performing data collection campaigns at a canonical, controlled environment for complete radiological characterization to help construct and benchmark a high-fidelity model with quantified system geometries, detector response functions,more » and source terms for background and threat objects. This data also provides an archival, benchmark dataset that can be used by the radiation detection community. The data reported here spans four data collection campaigns conducted between May 2015 and September 2016.« less

Metals as radio-enhancers in oncology: The industry perspective

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pottier, Agnés, E-mail: agnes.pottier@nanobiotix.com; Borghi, Elsa; Levy, Laurent

Radio-enhancers, metal-based nanosized agents, could play a key role in oncology. They may unlock the potential of radiotherapy by enhancing the radiation dose deposit within tumors when the ionizing radiation source is ‘on’, while exhibiting chemically inert behavior in cellular and subcellular systems when the radiation beam is ‘off’. Important decision points support the development of these new type of therapeutic agents originated from nanotechnology. Here, we discuss from an industry perspective, the interest of developing radio-enhancer agents to improve tumor control, the relevance of nanotechnology to achieve adequate therapeutic attributes, and present some considerations for their development in oncology.more » - Highlights: • Oncology is a field of high unmet medical need. • Despites of its widespread usage, radiation therapy presents a narrow therapeutic window. • High density material at the nanoscale may enhance radiation dose deposit from cancer cells. • Metal-based nanosized radio-enhancers could unlock the potential of radiotherapy.« less

Effects of Free Molecular Heating on the Space Shuttle Active Thermal Control System

NASA Technical Reports Server (NTRS)

McCloud, Peter L.; Wobick, Craig A.

2007-01-01

During Space Transportation System (STS) flight 121, higher than predicted radiator outlet temperatures were experienced from post insertion and up until nominal correction (NC) burn two. Effects from the higher than predicted heat loads on the radiator panels led to an additional 50 lbm of supply water consumed by the Flash Evaporator System (FES). Post-flight analysis and research revealed that the additional heat loads were due to Free Molecular Heating (FMH) on the radiator panels, which previously had not been considered as a significant environmental factor for the Space Shuttle radiators. The current Orbiter radiator heat flux models were adapted to incorporate the effects of FMH in addition to solar, earth infrared and albedo sources. Previous STS flights were also examined to find additional flight data on the FMH environment. Results of the model were compared to flight data and verified against results generated by the National Aeronautics and Space Administration (NASA), Johnson Space Center (JSC) Aero-sciences group to verify the accuracy of the model.

Development of an omnidirectional gamma-ray imaging Compton camera for low-radiation-level environmental monitoring

NASA Astrophysics Data System (ADS)

Watanabe, Takara; Enomoto, Ryoji; Muraishi, Hiroshi; Katagiri, Hideaki; Kagaya, Mika; Fukushi, Masahiro; Kano, Daisuke; Satoh, Wataru; Takeda, Tohoru; Tanaka, Manobu M.; Tanaka, Souichi; Uchida, Tomohisa; Wada, Kiyoto; Wakamatsu, Ryo

2018-02-01

We have developed an omnidirectional gamma-ray imaging Compton camera for environmental monitoring at low levels of radiation. The camera consisted of only six CsI(Tl) scintillator cubes of 3.5 cm, each of which was readout by super-bialkali photo-multiplier tubes (PMTs). Our camera enables the visualization of the position of gamma-ray sources in all directions (∼4π sr) over a wide energy range between 300 and 1400 keV. The angular resolution (σ) was found to be ∼11°, which was realized using an image-sharpening technique. A high detection efficiency of 18 cps/(µSv/h) for 511 keV (1.6 cps/MBq at 1 m) was achieved, indicating the capability of this camera to visualize hotspots in areas with low-radiation-level contamination from the order of µSv/h to natural background levels. Our proposed technique can be easily used as a low-radiation-level imaging monitor in radiation control areas, such as medical and accelerator facilities.

Multimodal nonlinear nanophotonics (Conference Presentation)

NASA Astrophysics Data System (ADS)

Kivshar, Yuri S.

2017-05-01

Nonlinear nanophotonics is a rapidly developing field of research with many potential applications for the design of nonlinear nanoantennas, light sources, nanolasers, and ultrafast miniature metadevices. A tight confinement of the local electromagnetic fields in resonant photonic nanostructures can boost nonlinear optical effects, thus offering versatile opportunities for the subwavelength control of light. To achieve the desired functionalities, it is essential to gain flexible control over the near- and far-field properties of nanostructures. To engineer nonlinear scattering from resonant nanoscale elements, both modal and multipolar control of the nonlinear response are widely exploited for enhancing the near-field interaction and optimizing the radiation directionality. Motivated by the recent progress of all-dielectric nanophotonics, where the electric and magnetic multipolar contributions may become comparable, here we review the advances in the recently emerged field of multipolar nonlinear nanophotonics, starting from earlier relevant studies of metallic and metal-dielectric structures supporting localized plasmonic resonances to then discussing the latest results for all-dielectric nanostructures driven by Mie-type multipolar resonances and optically induced magnetic response. These recent developments suggest intriguing opportunities for a design of nonlinear subwavelength light sources with reconfigurable radiation characteristics and engineering large effective optical nonlinearities at the nanoscale, which could have important implications for novel nonlinear photonic devices operating beyond the diffraction limit.

Human exposure to high natural background radiation: what can it teach us about radiation risks?

PubMed Central

Hendry, Jolyon H; Simon, Steven L; Wojcik, Andrzej; Sohrabi, Mehdi; Burkart, Werner; Cardis, Elisabeth; Laurier, Dominique; Tirmarche, Margot; Hayata, Isamu

2014-01-01

Natural radiation is the major source of human exposure to ionising radiation, and its largest contributing component to effective dose arises from inhalation of 222Rn and its radioactive progeny. However, despite extensive knowledge of radiation risks gained through epidemiologic investigations and mechanistic considerations, the health effects of chronic low-level radiation exposure are still poorly understood. The present paper reviews the possible contribution of studies of populations living in high natural background radiation (HNBR) areas (Guarapari, Brazil; Kerala, India; Ramsar, Iran; Yangjiang, China), including radon-prone areas, to low dose risk estimation. Much of the direct information about risk related to HNBR comes from case–control studies of radon and lung cancer, which provide convincing evidence of an association between long-term protracted radiation exposures in the general population and disease incidence. The success of these studies is mainly due to the careful organ dose reconstruction (with relatively high doses to the lung), and to the fact that large-scale collaborative studies have been conducted to maximise the statistical power and to ensure the systematic collection of information on potential confounding factors. In contrast, studies in other (non-radon) HNBR areas have provided little information, relying mainly on ecological designs and very rough effective dose categorisations. Recent steps taken in China and India to establish cohorts for follow-up and to conduct nested case–control studies may provide useful information about risks in the future, provided that careful organ dose reconstruction is possible and information is collected on potential confounding factors. PMID:19454802

On beam shaping of the field radiated by a line source coupled to finite or infinite photonic crystals.

PubMed

Ceccuzzi, Silvio; Jandieri, Vakhtang; Baccarelli, Paolo; Ponti, Cristina; Schettini, Giuseppe

2016-04-01

Comparison of the beam-shaping effect of a field radiated by a line source, when an ideal infinite structure constituted by two photonic crystals and an actual finite one are considered, has been carried out by means of two different methods. The lattice sums technique combined with the generalized reflection matrix method is used to rigorously investigate the radiation from the infinite photonic crystals, whereas radiation from crystals composed of a finite number of rods along the layers is analyzed using the cylindrical-wave approach. A directive radiation is observed with the line source embedded in the structure. With an increased separation distance between the crystals, a significant edge diffraction appears that provides the main radiation mechanism in the finite layout. Suitable absorbers are implemented to reduce the above-mentioned diffraction and the reflections at the boundaries, thus obtaining good agreement between radiation patterns of a localized line source coupled to finite and infinite photonic crystals, when the number of periods of the finite structure is properly chosen.

Active Control of Fan-Generated Tone Noise

NASA Technical Reports Server (NTRS)

Gerhold, Carl H.

1995-01-01

This paper reports on an experiment to control the noise radiated from the inlet of a ducted fan using a time domain active adaptive system. The control ,sound source consists of loudspeakers arranged in a ring around the fan duct. The error sensor location is in the fan duct. The purpose of this experiment is to demonstrate that the in-duct error sensor reduces the mode spillover in the far field, thereby increasing the efficiency of the control system. The control system is found to reduce the blade passage frequency tone significantly in the acoustic far field when the mode orders of the noise source and of the control source are the same, when the dominant wave in the duct is a plane wave. The presence of higher order modes in the duct reduces the noise reduction efficiency, particularly near the mode cut-on where the standing wave component is strong, but the control system converges stably. The control system is stable and converges when the first circumferential mode is generated in the duct. The control system is found to reduce the fan noise in the far field on an arc around the fan inlet by as much as 20 dB with none of the sound amplification associated with mode spillover.

Increased impedance near cut-off in plasma-like media leading to emission of high-power, narrow-bandwidth radiation

PubMed Central

Hur, M. S.; Ersfeld, B.; Noble, A.; Suk, H.; Jaroszynski, D. A.

2017-01-01

Ultra-intense, narrow-bandwidth, electromagnetic pulses have become important tools for exploring the characteristics of matter. Modern tuneable high-power light sources, such as free-electron lasers and vacuum tubes, rely on bunching of relativistic or near-relativistic electrons in vacuum. Here we present a fundamentally different method for producing narrow-bandwidth radiation from a broad spectral bandwidth current source, which takes advantage of the inflated radiation impedance close to cut-off in a medium with a plasma-like permittivity. We find that by embedding a current source in this cut-off region, more than an order of magnitude enhancement of the radiation intensity is obtained compared with emission directly into free space. The method suggests a simple and general way to flexibly use broadband current sources to produce broad or narrow bandwidth pulses. As an example, we demonstrate, using particle-in-cell simulations, enhanced monochromatic emission of terahertz radiation using a two-colour pumped current source enclosed by a tapered waveguide. PMID:28071681

Increased impedance near cut-off in plasma-like media leading to emission of high-power, narrow-bandwidth radiation

NASA Astrophysics Data System (ADS)

Hur, M. S.; Ersfeld, B.; Noble, A.; Suk, H.; Jaroszynski, D. A.

2017-01-01

Ultra-intense, narrow-bandwidth, electromagnetic pulses have become important tools for exploring the characteristics of matter. Modern tuneable high-power light sources, such as free-electron lasers and vacuum tubes, rely on bunching of relativistic or near-relativistic electrons in vacuum. Here we present a fundamentally different method for producing narrow-bandwidth radiation from a broad spectral bandwidth current source, which takes advantage of the inflated radiation impedance close to cut-off in a medium with a plasma-like permittivity. We find that by embedding a current source in this cut-off region, more than an order of magnitude enhancement of the radiation intensity is obtained compared with emission directly into free space. The method suggests a simple and general way to flexibly use broadband current sources to produce broad or narrow bandwidth pulses. As an example, we demonstrate, using particle-in-cell simulations, enhanced monochromatic emission of terahertz radiation using a two-colour pumped current source enclosed by a tapered waveguide.

The Global Enery and Water Cycle Experiment Science Strategy

NASA Technical Reports Server (NTRS)

Chahine, M. T.

1997-01-01

The distribution of water in the atmosphere and at the surface of the Earth is the most influential factor regulating our environment, not only because water is essential for life but also because through phase transitions it is the main energy source that control clouds and radiation and drives the global circulation of the atmosphere.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schüller, Andreas, E-mail: andreas.schueller@ptb.de; Meier, Markus; Selbach, Hans-Joachim

Purpose: The aim of this study was to investigate whether a chamber-type-specific radiation quality correction factor k{sub Q} can be determined in order to measure the reference air kerma rate of {sup 60}Co high-dose-rate (HDR) brachytherapy sources with acceptable uncertainty by means of a well-type ionization chamber calibrated for {sup 192}Ir HDR sources. Methods: The calibration coefficients of 35 well-type ionization chambers of two different chamber types for radiation fields of {sup 60}Co and {sup 192}Ir HDR brachytherapy sources were determined experimentally. A radiation quality correction factor k{sub Q} was determined as the ratio of the calibration coefficients for {supmore » 60}Co and {sup 192}Ir. The dependence on chamber-to-chamber variations, source-to-source variations, and source strength was investigated. Results: For the PTW Tx33004 (Nucletron source dosimetry system (SDS)) well-type chamber, the type-specific radiation quality correction factor k{sub Q} is 1.19. Note that this value is valid for chambers with the serial number, SN ≥ 315 (Nucletron SDS SN ≥ 548) onward only. For the Standard Imaging HDR 1000 Plus well-type chambers, the type-specific correction factor k{sub Q} is 1.05. Both k{sub Q} values are independent of the source strengths in the complete clinically relevant range. The relative expanded uncertainty (k = 2) of k{sub Q} is U{sub k{sub Q}} = 2.1% for both chamber types. Conclusions: The calibration coefficient of a well-type chamber for radiation fields of {sup 60}Co HDR brachytherapy sources can be calculated from a given calibration coefficient for {sup 192}Ir radiation by using a chamber-type-specific radiation quality correction factor k{sub Q}. However, the uncertainty of a {sup 60}Co calibration coefficient calculated via k{sub Q} is at least twice as large as that for a direct calibration with a {sup 60}Co source.« less

Dense plasma focus (DPF) accelerated non radio isotopic radiological source

DOEpatents

Rusnak, Brian; Tang, Vincent

2017-01-31

A non-radio-isotopic radiological source using a dense plasma focus (DPF) to produce an intense z-pinch plasma from a gas, such as helium, and which accelerates charged particles, such as generated from the gas or injected from an external source, into a target positioned along an acceleration axis and of a type known to emit ionizing radiation when impinged by the type of accelerated charged particles. In a preferred embodiment, helium gas is used to produce a DPF-accelerated He2+ ion beam to a beryllium target, to produce neutron emission having a similar energy spectrum as a radio-isotopic AmBe neutron source. Furthermore, multiple DPFs may be stacked to provide staged acceleration of charged particles for enhancing energy, tunability, and control of the source.

Radiation force on absorbing targets and power measurements of a high intensity focused ultrasound (HIFU) source

NASA Astrophysics Data System (ADS)

Qian, Zuwen; Zhu, Zhemin; Ye, Shigong; Jiang, Wenhua; Zhu, Houqing; Yu, Jinshen

2010-10-01

Based on the analytic expressions for the radiated field of a circular concave piston given by Hasegawa et al., an integral for calculation of the radiation force on a plane absorbing target in a spherically focused field is derived. A general relation between acoustic power P and normal radiation force F n is obtained under the condition of kr ≫ 1. Numerical computation is carried out by using the symbolic computation program for practically focused sources and absorbing circular targets. The results show that, for a given source, there is a range of target positions where the radiation force is independent of the target’s position under the assumption that the contribution of the acoustic field behind the target to the radiation force can be neglected. The experiments are carried out and confirm that there is a range of target positions where the measured radiation force is basically independent of the target’s position even at high acoustic power (up to 700 W). It is believed that when the radiation force method is used to measure the acoustic power radiated from a focused source, the size of the target must be selected in such a way that no observable sound can be found in the region behind the target.

Radiation resistant PIDECα cell using photon intermediate direct energy conversion and a 210Po source.

PubMed

Weaver, Charles L; Schott, Robert J; Prelas, Mark A; Wisniewski, Denis A; Rothenberger, Jason B; Lukosi, Eric D; Oh, Kyuhak

2018-02-01

Radiation damage is a significant concern with both alphavoltaic and betavoltaic cells because their performance degrades, especially with high-energy - (>200keV) beta and alpha particles. Indirect excitation methods, such as the Photon Intermediate Direct Energy Conversion (PIDEC) framework, can protect the transducer from radiation. A nuclear battery using a 90 Sr beta source was constructed by the author's research group, which demonstrated the radiation resistance of a PIDEC cell driven by beta particles (PIDECβ cell). Use of alpha sources to drive nuclear batteries would appear to be much more attractive than beta sources due to higher potential power density. However, they are also subject to higher rates of radiation damage. This paper describes the successful incorporation of alpha particles into the PIDEC framework using the alpha emitter 210 Po to form a PIDECα cell. The PIDECα cell transducer was exposed to alpha particles for over one year without experiencing adverse effects from radiation damage. Copyright © 2017 Elsevier Ltd. All rights reserved.

Analysis of Water Vapour Flux Between Alpine Wetlands Underlying the Surface and Atmosphere in the Source Region of the Yellow River

NASA Astrophysics Data System (ADS)

Xie, Y.; Wen, J.; Liu, R.; Wang, X.; JIA, D.

2017-12-01

Wetland underlying surface is sensitive to climate change. Analysis of the degree of coupling between wetlands and the atmosphere and a quantitative assessment of how environmental factors influence latent heat flux have considerable scientific significance. Previous studies, which focused on the forest, grassland and farmland ecosystems, lack research on the alpine wetlands. In addition, research on the environmental control mechanism of latent heat flux is still qualitative and lacks quantitative evaluations and calculations. Using data from the observational tests of the Maduo Observatory of Climate and Environment of the Northwest Institute of Eco-Environment and Resource, CAS, from June 1 to August 31, 2014, this study analysed the time-varying characteristics and causes of the degree of coupling between alpine wetlands underlying surface and the atmosphere and quantitatively calculated the influences of different environmental factors (solar radiation and vapour pressure deficit) on latent heat flux. The results were as follows: Due to the diurnal variations of solar radiation and wind speed, the diurnal variations of the Ω factor present a trend in which the Ω factor are small in the morning and large in the evening. Due to the vegetation growing cycle, the seasonal variations of the Ω factor present a reverse "U" trend . These trends are similar to the diurnal and seasonal variations of the absolute control exercised by solar radiation over the latent heat flux. This conforms to omega theory. The values for average absolute atmospheric factor (surface factor or total ) control exercised by solar radiation and water vapour pressure are 0.20 (0.02 or 0.22 ) and 0.005 (-0.07 or -0.06) W·m-2·Pa-1, respectively.. Generally speaking, solar radiation and water vapour pressure deficit exert opposite forces on the latent heat flux. The average Ω factor is high during the vegetation growing season, with a value of 0.38, and the degree of coupling between the alpine wetland surface and the atmosphere system is low. The actual measurements agree with omega theory. The latent heat flux is mainly influenced by solar radiation. From the above, our study has provided reference information for exploring the influences of environmental factors on the latent heat flux over the alpine wetlands of the Yellow River source region.

Development of extreme ultraviolet and soft x-ray multilayer optics for scientific studies with femtosecond/attosecond sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aquila, Andrew Lee

The development of multilayer optics for extreme ultraviolet (EUV) radiation has led to advancements in many areas of science and technology, including materials studies, EUV lithography, water window microscopy, plasma imaging, and orbiting solar physics imaging. Recent developments in femtosecond and attosecond EUV pulse generation from sources such as high harmonic generation lasers, combined with the elemental and chemical specificity provided by EUV radiation, are opening new opportunities to study fundamental dynamic processes in materials. Critical to these efforts is the design and fabrication of multilayer optics to transport, focus, shape and image these ultra-fast pulses This thesis describes themore » design, fabrication, characterization, and application of multilayer optics for EUV femtosecond and attosecond scientific studies. Multilayer mirrors for bandwidth control, pulse shaping and compression, tri-material multilayers, and multilayers for polarization control are described. Characterization of multilayer optics, including measurement of material optical constants, reflectivity of multilayer mirrors, and metrology of reflected phases of the multilayer, which is critical to maintaining pulse size and shape, were performed. Two applications of these multilayer mirrors are detailed in the thesis. In the first application, broad bandwidth multilayers were used to characterize and measure sub-100 attosecond pulses from a high harmonic generation source and was performed in collaboration with the Max-Planck institute for Quantum Optics and Ludwig- Maximilians University in Garching, Germany, with Professors Krausz and Kleineberg. In the second application, multilayer mirrors with polarization control are useful to study femtosecond spin dynamics in an ongoing collaboration with the T-REX group of Professor Parmigiani at Elettra in Trieste, Italy. As new ultrafast x-ray sources become available, for example free electron lasers, the multilayer designs described in this thesis can be extended to higher photon energies, and such designs can be used with those sources to enable new scientific studies, such as molecular bonding, phonon, and spin dynamics.« less

The role of near infrared radiation in photoaging of the skin.

PubMed

Schroeder, Peter; Haendeler, Judith; Krutmann, Jean

2008-07-01

Infrared (IR) radiation is non-ionizing, electromagnetic radiation with wavelengths between 760 nm and 1 mm, which is further divided into IRA, IRB and IRC. IR accounts for more than half of the solar energy that reaches the human skin. While IRB and IRC do not penetrate deeply into the skin, more than 65% of IRA reaches the dermis. Human skin is increasingly exposed to IRA-radiation; most relevant sources are (i) natural solar radiation consisting of over 30% IRA, (ii) artificial IRA sources used for therapeutic or wellness purposes and (iii) artificial UV sources contaminated with IRA. As part of natural sunlight, IRA significantly contributes to extrinsic skin aging. This article reviews the cutaneous effects of IRA-radiation, the underlying molecular mechanisms and the available protective strategies.

Status of the SAGA Light Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaneyasu, T.; Takabayashi, Y.; Iwasaki, Y.

The SAGA Light Source (SAGA-LS) is a synchrotron radiation facility consisting of a 255 MeV injector linac and a 1.4 GeV storage ring that is 75.6 m in circumference. The SAGA-LS has been stably providing synchrotron radiation to users since it first started user operation in February 2006. Along with the user operation, various machine improvements have been made over the past years, including upgrading the injector linac control system, replacing a septum magnet and constructing a beam diagnostic system. In addition to these improvements, insertion devices have been developed and installed. An APPLE-II type variable polarization undulator was installedmore » in 2008. To address the demand from users for high-flux hard x-rays, a superconducting 4 T class wiggler is being developed. An experimental setup for generating MeV photons by laser Compton scattering is being constructed for beam monitoring and future user experiments.« less

2010 Annual Health Physics Report for the HEU Transparency Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Radev, Radoslav

2011-05-16

During the 2010 calendar year, Lawrence Livermore National Laboratory (LLNL) provided health physics support for the Highly Enriched Uranium (HEU) Transparency Program for external and internal radiation protection. LLNL also provided technical expertise related to BDMS radioactive sources and Russian radiation safety regulatory compliance. For the calendar year 2010, there were 141 person-trips that required dose monitoring of the U.S. monitors. Of the 141 person-trips, 129 person-trips were Special Monitoring Visits (SMVs) and 12 person-trips were Transparency Monitoring Office (TMO) trips. In 8 of these TMO trips the TMO monitors participated also in the UEIE SMVs and in 2 TMOmore » trips the TMO monitors participated in UEIE and MPA SMVs. There were three monitoring visits (source changes) that were back-to-back SMVs with a total of 25 monitors. LLNL’s Hazard Control Department laboratories provided the dosimetry services for the HEU Transparency monitors.« less

Experimental and theoretical studies of near-ground acoustic radiation propagation in the atmosphere

NASA Astrophysics Data System (ADS)

Belov, Vladimir V.; Burkatovskaya, Yuliya B.; Krasnenko, Nikolai P.; Rakov, Aleksandr S.; Rakov, Denis S.; Shamanaeva, Liudmila G.

2017-11-01

Results of experimental and theoretical studies of the process of near-ground propagation of monochromatic acoustic radiation on atmospheric paths from a source to a receiver taking into account the contribution of multiple scattering on fluctuations of atmospheric temperature and wind velocity, refraction of sound on the wind velocity and temperature gradients, and its reflection by the underlying surface for different models of the atmosphere depending the sound frequency, coefficient of reflection from the underlying surface, propagation distance, and source and receiver altitudes are presented. Calculations were performed by the Monte Carlo method using the local estimation algorithm by the computer program developed by the authors. Results of experimental investigations under controllable conditions are compared with theoretical estimates and results of analytical calculations for the Delany-Bazley impedance model. Satisfactory agreement of the data obtained confirms the correctness of the suggested computer program.

Recovery of damage in rad-hard MOS devices during and after irradiation by electrons, protons, alphas, and gamma rays

NASA Technical Reports Server (NTRS)

Brucker, G. J.; Van Gunten, O.; Stassinopoulos, E. G.; Shapiro, P.; August, L. S.; Jordan, T. M.

1983-01-01

This paper reports on the recovery properties of rad-hard MOS devices during and after irradiation by electrons, protons, alphas, and gamma rays. The results indicated that complex recovery properties controlled the damage sensitivities of the tested parts. The results also indicated that damage sensitivities depended on dose rate, total dose, supply bias, gate bias, transistor type, radiation source, and particle energy. The complex nature of these dependencies make interpretation of LSI device performance in space (exposure to entire electron and proton spectra) difficult, if not impossible, without respective ground tests and analyses. Complete recovery of n-channel shifts was observed, in some cases within hours after irradiation, with equilibrium values of threshold voltages greater than their pre-irradiation values. This effect depended on total dose, radiation source, and gate bias during exposure. In contrast, the p-channel shifts recovered only 20 percent within 30 days after irradiation.

Microcautery based on zinc metallic nanoparticles photodeposited on the core of an optical fiber

NASA Astrophysics Data System (ADS)

Zaca-Morán, P.; Pastelín, C. F.; Morán, C.; Pérez-Sánchez, G. F.; Chávez, F.

2017-01-01

The experimental arrangement of a microcautery implemented by an optical fiber with zinc nanoparticles (ZnNPs) photodeposited on its core for the cauterization and coagulation in blood vessels hemostasis processes is presented. The interaction between a laser radiation source and the ZnNPS on the fiber core produces a controllable punctual heat source through the radiation intensity, which is capable of reaching a temperature up to 200 °C covering an area of approximately ten micrometers. By using three-to-four-month-old rats of CIIZ-V strain, we made several microcauterization experimental tests to stop blood flow. The findings show that the microcautery obliterates the smooth muscle of the blood vessels concatenating mutually to tissue in an average time of three seconds, at the same time, the blood elements responsible for the coagulation are thermally activated and thus the bleeding is stopped.

Effects of radiation and creep on viscoelastic damping materials

NASA Astrophysics Data System (ADS)

Henderson, John P.; Lewis, Tom M.; Murrell, Fred H.; Mangra, Danny

1995-05-01

The Advanced Photon Source (APS), under construction at Argonne National Laboratory (ANL), requires precise alignment of several large magnets. Submicron vibratory displacements of the magnets can degrade the performance of this important facility. Viscoelastic materials (VEM) have been shown to be effective in the control of the vibration of these magnets. Damping pads, placed under the magnet support structures in the APS storage ring, use thin layers of VEM. These soft VEM layers are subject to both high-energy radiation environment and continuous through-the-thickness compressive loads. Material experiments were conducted to answer concerns over the long term effects of the radiation environment and creep in the viscoelastic damping layers. The effects of exposure to radiation as high as 108 rad on the complex modulus were measured. Through-the-thickness creep displacements of VEM thin layers subjected to static loads of 50 psi were measured. Creep tests were conducted at elevated temperatures. Time-temperature equivalence principles were used to project creep displacements at room temperatures over several years. These damping material measurements should be of interest to vibration control engineers working with a variety of applications of fields ranging from aerospace to industrial machinery.

Effect of ionizing radiation on some quality attributes of nutraceutically valued lotus seeds.

PubMed

Bhat, Rajeev; Karim, A A

2009-01-01

Radiation processing has been employed successfully for value addition of food and agricultural products. Preliminary studies were undertaken to evaluate the changes induced by ionizing radiation (up to 30 kGy), in the form of gamma irradiation and electron beam irradiation, on some quality attributes and nutritive values of nutraceutically valued lotus seeds. Significant loss in seed firmness was recorded between control and irradiated seeds, irrespective of radiation source. Similarly, the specific viscosity of irradiated lotus seeds decreased significantly up to a dose of 7.5 kGy. Starch increased after exposure to gamma or electron beam irradiation, whereas the total phenolic contents were decreased. Gamma irradiation revealed an enhancement in protein, while the electron beam showed a decrease. Partial oxidation of the seeds during radiation treatments might have occurred as evidenced from the decomposition profiles (thermogravimetry) during heating. It is evident that ionizing radiation brought about significant and variable changes in the quality and nutritive values of lotus seed. Further exploration of this technology for safety and quality is warranted.

Enhancement of efficiency in the use of light for cultivation of plants in controlled ecological systems

NASA Technical Reports Server (NTRS)

Mashinsky, A. L.; Oreshkin, V. I.; Nechitailo, G. S.

1994-01-01

The problems of plant cultivation with the use of artificial lighting are related to energetics and, initially, to the lack of effective sources for photosynthesis, secondly to the necessity to supply a system with a considerable power in the form of light energy and to remove transformed thermal energy, and finally to economic considerations. These problems are solved by three ways: by the choice of effective radiation sources, design approaches, and technological methods of cultivation. Here we shall consider the first two ways.

Tunable terahertz radiation source

DOEpatents

Boulaevskii, Lev; Feldmann, David M; Jia, Quanxi; Koshelev, Alexei; Moody, Nathan A

2014-01-21

Terahertz radiation source and method of producing terahertz radiation, said source comprising a junction stack, said junction stack comprising a crystalline material comprising a plurality of self-synchronized intrinsic Josephson junctions; an electrically conductive material in contact with two opposing sides of said crystalline material; and a substrate layer disposed upon at least a portion of both the crystalline material and the electrically-conductive material, wherein the crystalline material has a c-axis which is parallel to the substrate layer, and wherein the source emits at least 1 mW of power.

Nonuniformity correction of imaging systems with a spatially nonhomogeneous radiation source.

PubMed

Gutschwager, Berndt; Hollandt, Jörg

2015-12-20

We present a novel method of nonuniformity correction of imaging systems in a wide optical spectral range by applying a radiation source with an unknown and spatially nonhomogeneous radiance or radiance temperature distribution. The benefit of this method is that it can be applied with radiation sources of arbitrary spatial radiance or radiance temperature distribution and only requires the sufficient temporal stability of this distribution during the measurement process. The method is based on the recording of several (at least three) images of a radiation source and a purposeful row- and line-shift of these sequent images in relation to the first primary image. The mathematical procedure is explained in detail. Its numerical verification with a source of a predefined nonhomogenous radiance distribution and a thermal imager of a predefined nonuniform focal plane array responsivity is presented.

Intense terahertz radiation from relativistic laser–plasma interactions

DOE PAGES

Liao, G. Q.; Li, Y. T.; Li, C.; ...

2016-11-02

The development of tabletop intense terahertz (THz) radiation sources is extremely important for THz science and applications. This study presents our measurements of intense THz radiation from relativistic laser–plasma interactions under different experimental conditions. Several THz generation mechanisms have been proposed and investigated, including coherent transition radiation (CTR) emitted by fast electrons from the target rear surface, transient current radiation at the front of the target, and mode conversion from electron plasma waves (EPWs) to THz waves. Finally, the results indicate that relativistic laser plasma is a promising driver of intense THz radiation sources.

10 CFR 36.61 - Inspection and maintenance.

Code of Federal Regulations, 2011 CFR

2011-01-01

... NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR IRRADIATORS Operation of...) Functioning of the source position indicator required by § 36.31(b). (3) Operability of the radiation monitor for radioactive contamination in pool water required by § 36.59(b) using a radiation check source, if...

21 CFR 179.21 - Sources of radiation used for inspection of food, for inspection of packaged food, and for...

Code of Federal Regulations, 2013 CFR

2013-04-01

... radiations at energy levels of not more than 2.2 million electron volts from one of the following isotopes... in food. (4) Machine sources producing X-radiation at energies no greater than 10 million electron...

21 CFR 179.21 - Sources of radiation used for inspection of food, for inspection of packaged food, and for...

Code of Federal Regulations, 2012 CFR

2012-04-01

... radiations at energy levels of not more than 2.2 million electron volts from one of the following isotopes... in food. (4) Machine sources producing X-radiation at energies no greater than 10 million electron...

21 CFR 179.21 - Sources of radiation used for inspection of food, for inspection of packaged food, and for...

Code of Federal Regulations, 2011 CFR

2011-04-01

... radiations at energy levels of not more than 2.2 million electron volts from one of the following isotopes... in food. (4) Machine sources producing X-radiation at energies no greater than 10 million electron...

Focused X-ray source

DOEpatents

Piestrup, Melvin A.; Boyers, David G.; Pincus, Cary I.; Maccagno, Pierre

1990-01-01

An intense, relatively inexpensive X-ray source (as compared to a synchrotron emitter) for technological, scientific, and spectroscopic purposes. A conical radiation pattern produced by a single foil or stack of foils is focused by optics to increase the intensity of the radiation at a distance from the conical radiator.

ATTENUATION OF COBALT-60 RADIATION FROM A SOURCE DISTRIBUTED AROUND A CONCRETE BLOCKHOUSE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Batter, J.F.; Starbird, A.W.

1961-06-15

Two radiation-shielding experiments were performed upon a simple blockhouse structure. The blockhouse was exposed to a simulated fallout field, and the radiation penetrating the structure was measured. The radiation field was produced by circulating a sealed cobalt-60 source through polyethylene tubing predistributed over an octant centered on the test building. Experimental details are described and results tabulated. (auth)

Power Balance and Impurity Studies in TCS

NASA Astrophysics Data System (ADS)

Grossnickle, J. A.; Pietrzyk, Z. A.; Vlases, G. C.

2003-10-01

A "zero-dimension" power balance model was developed based on measurements of absorbed power, radiated power, absolute D_α, temperature, and density for the TCS device. Radiation was determined to be the dominant source of power loss for medium to high density plasmas. The total radiated power was strongly correlated with the Oxygen line radiation. This suggests Oxygen is the dominant radiating species, which was confirmed by doping studies. These also extrapolate to a Carbon content below 1.5%. Determining the source of the impurities is an important question that must be answered for the TCS upgrade. Preliminary indications are that the primary sources of Oxygen are the stainless steel end cones. A Ti gettering system is being installed to reduce this Oxygen source. A field line code has been developed for use in tracking where open field lines terminate on the walls. Output from this code is also used to generate grids for an impurity tracking code.

SPRAI: coupling of radiative feedback and primordial chemistry in moving mesh hydrodynamics

NASA Astrophysics Data System (ADS)

Jaura, O.; Glover, S. C. O.; Klessen, R. S.; Paardekooper, J.-P.

2018-04-01

In this paper, we introduce a new radiative transfer code SPRAI (Simplex Photon Radiation in the Arepo Implementation) based on the SIMPLEX radiation transfer method. This method, originally used only for post-processing, is now directly integrated into the AREPO code and takes advantage of its adaptive unstructured mesh. Radiated photons are transferred from the sources through the series of Voronoi gas cells within a specific solid angle. From the photon attenuation, we derive corresponding photon fluxes and ionization rates and feed them to a primordial chemistry module. This gives us a self-consistent method for studying dynamical and chemical processes caused by ionizing sources in primordial gas. Since the computational cost of the SIMPLEX method does not scale directly with the number of sources, it is convenient for studying systems such as primordial star-forming haloes that may form multiple ionizing sources.

Marine disposal of radioactive wastes

NASA Astrophysics Data System (ADS)

Woodhead, D. S.

1980-03-01

In a general sense, the main attraction of the marine environment as a repository for the wastes generated by human activities lies in the degree of dispersion and dilution which is readily attainable. However, the capacity of the oceans to receive wastes without unacceptable consequences is clearly finite and this is even more true of localized marine environments such as estuaries, coastal waters and semi-enclosed seas. Radionuclides have always been present in the marine environment and marine organisms and humans consuming marine foodstuffs have always been exposed, to some degree, to radiation from this source. The hazard associated with ionizing radiations is dependent upon the absorption of energy from the radiation field within some biological entity. Thus any disposal of radioactive wastes into the marine environment has consequences, the acceptability of which must be assessed in terms of the possible resultant increase in radiation exposure of human and aquatic populations. In the United Kingdom the primary consideration has been and remains the safe-guarding of public health. The control procedures are therefore designed to minimize as far as practicable the degree of human exposure within the overall limits recommended as acceptable by the International Commission on Radiological Protection. There are several approaches through which control could be exercised and the strengths and weaknesses of each are considered. In this review the detailed application of the critical path technique to the control of the discharge into the north-east Irish Sea from the fuel reprocessing plant at Windscale is given as a practical example. It will be further demonstrated that when human exposure is controlled in this way no significant risk attaches to the increased radiation exposure experienced by populations of marine organisms in the area.

EVALUATING THE SENSITIVITY OF RADIONUCLIDE DETECTORS FOR CONDUCTING A MARITIME ON-BOARD SEARCH USING MONTE CARLO SIMULATION IMPLEMENTED IN AVERT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, S; Dave Dunn, D

The sensitivity of two specific types of radionuclide detectors for conducting an on-board search in the maritime environment was evaluated using Monte Carlo simulation implemented in AVERT{reg_sign}. AVERT{reg_sign}, short for the Automated Vulnerability Evaluation for Risk of Terrorism, is personal computer based vulnerability assessment software developed by the ARES Corporation. The sensitivity of two specific types of radionuclide detectors for conducting an on-board search in the maritime environment was evaluated using Monte Carlo simulation. The detectors, a RadPack and also a Personal Radiation Detector (PRD), were chosen from the class of Human Portable Radiation Detection Systems (HPRDS). Human Portable Radiationmore » Detection Systems (HPRDS) serve multiple purposes. In the maritime environment, there is a need to detect, localize, characterize, and identify radiological/nuclear (RN) material or weapons. The RadPack is a commercially available broad-area search device used for gamma and also for neutron detection. The PRD is chiefly used as a personal radiation protection device. It is also used to detect contraband radionuclides and to localize radionuclide sources. Neither device has the capacity to characterize or identify radionuclides. The principal aim of this study was to investigate the sensitivity of both the RadPack and the PRD while being used under controlled conditions in a simulated maritime environment for detecting hidden RN contraband. The detection distance varies by the source strength and the shielding present. The characterization parameters of the source are not indicated in this report so the results summarized are relative. The Monte Carlo simulation results indicate the probability of detection of the RN source at certain distances from the detector which is a function of transverse speed and instrument sensitivity for the specified RN source.« less

Luminescent light source for laser pumping and laser system containing same

DOEpatents

Hamil, Roy A.; Ashley, Carol S.; Brinker, C. Jeffrey; Reed, Scott; Walko, Robert J.

1994-01-01

The invention relates to a pumping lamp for use with lasers comprising a porous substrate loaded with a component capable of emitting light upon interaction of the component with exciting radiation and a source of exciting radiation. Preferably, the pumping lamp comprises a source of exciting radiation, such as an electron beam, and an aerogel or xerogel substrate loaded with a component capable of interacting with the exciting radiation, e.g., a phosphor, to produce light, e.g., visible light, of a suitable band width and of a sufficient intensity to generate a laser beam from a laser material.

Radiation detector having a multiplicity of individual detecting elements

DOEpatents

Whetten, Nathan R.; Kelley, John E.

1985-01-01

A radiation detector has a plurality of detector collection element arrays immersed in a radiation-to-electron conversion medium. Each array contains a multiplicity of coplanar detector elements radially disposed with respect to one of a plurality of positions which at least one radiation source can assume. Each detector collector array is utilized only when a source is operative at the associated source position, negating the necessity for a multi-element detector to be moved with respect to an object to be examined. A novel housing provides the required containment of a high-pressure gas conversion medium.

Poisoning of Heat Pipes

NASA Technical Reports Server (NTRS)

Gillies, Donald; Lehoczky, Sandor; Palosz, Witold; Carpenter, Paul; Salvail, Pat

2007-01-01

Thermal management is critical to space exploration efforts. In particular, efficient transfer and control of heat flow is essential when operating high energy sources such as nuclear reactors. Thermal energy must be transferred to various energy conversion devices, and to radiators for safe and efficient rejection of excess thermal energy. Applications for space power demand exceptionally long periods of time with equipment that is accessible for limited maintenance only. Equally critical is the hostile and alien environment which includes high radiation from the reactor and from space (galactic) radiation. In space or lunar applications high vacuum is an issue, while in Martian operations the systems will encounter a CO2 atmosphere. The effect of contact at high temperature with local soil (regolith) in surface operations on the moon or other terrestrial bodies (Mars, asteroids) must be considered.

Special requirements for electronics to be used in robots in space

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sias, F.R.

1994-12-31

Robots have been developed for use in hazardous environments and space certainly falls in the category of a hazardous environment. Microcomputers and electronics used to control robotic systems to be employed in space face greater threats than earth-bound robots used around radioactive materials. It is well known that nuclear radiation damages semiconductor devices by causing charges to build up in silicon dioxide insulating layers when the devices are exposed to ionizing radiation. Electronics suffer from doses of radiation when used around radioactive materials; however, additional sources of damage are present when the robots are used in space. This paper ismore » a review of the problems that must be considered when developing electronics for robots to be used in space and some of the available solutions.« less

Investigation of laser dynamics, modulation and control by means of intra-cavity time varying perturbation

NASA Technical Reports Server (NTRS)

Harris, S. E.; Siegman, A. E.; Kuizenga, D. J.; Kung, A. H.; Young, J. F.; Bekkers, G. W.; Bloom, D. M.; Newton, J. H.; Phillion, D. W.

1975-01-01

The generation of tunable visible, infrared, and ultraviolet light is examined, along with the control of this light by means of novel mode-locking and modulation techniques. Transient mode-locking of the Nd:YAG laser and generation of short tunable pulses in the visible and the alkali metal inert gas excimer laser systems were investigated. Techniques for frequency conversion of high power and high energy laser radiation are discussed, along with high average power blue and UV laser light sources.

Training software using virtual-reality technology and pre-calculated effective dose data.

PubMed

Ding, Aiping; Zhang, Di; Xu, X George

2009-05-01

This paper describes the development of a software package, called VR Dose Simulator, which aims to provide interactive radiation safety and ALARA training to radiation workers using virtual-reality (VR) simulations. Combined with a pre-calculated effective dose equivalent (EDE) database, a virtual radiation environment was constructed in VR authoring software, EON Studio, using 3-D models of a real nuclear power plant building. Models of avatars representing two workers were adopted with arms and legs of the avatar being controlled in the software to simulate walking and other postures. Collision detection algorithms were developed for various parts of the 3-D power plant building and avatars to confine the avatars to certain regions of the virtual environment. Ten different camera viewpoints were assigned to conveniently cover the entire virtual scenery in different viewing angles. A user can control the avatar to carry out radiological engineering tasks using two modes of avatar navigation. A user can also specify two types of radiation source: Cs and Co. The location of the avatar inside the virtual environment during the course of the avatar's movement is linked to the EDE database. The accumulative dose is calculated and displayed on the screen in real-time. Based on the final accumulated dose and the completion status of all virtual tasks, a score is given to evaluate the performance of the user. The paper concludes that VR-based simulation technologies are interactive and engaging, thus potentially useful in improving the quality of radiation safety training. The paper also summarizes several challenges: more streamlined data conversion, realistic avatar movement and posture, more intuitive implementation of the data communication between EON Studio and VB.NET, and more versatile utilization of EDE data such as a source near the body, etc., all of which needs to be addressed in future efforts to develop this type of software.

RadTown USA Neighborhoods | US EPA

EPA Pesticide Factsheets

2016-09-08

Learn about radiation sources and uses in the interactive, virtual community of RadTown USA! Explore radiation sources and uses in homes and schools, medical buildings and laboratories and outdoors. You will also find information about coal-fired power plants and nuclear power plants, power lines and learn about responding to radiation emergencies.

Focused X-ray source

DOEpatents

Piestrup, M.A.; Boyers, D.G.; Pincus, C.I.; Maccagno, P.

1990-08-21

Disclosed is an intense, relatively inexpensive X-ray source (as compared to a synchrotron emitter) for technological, scientific, and spectroscopic purposes. A conical radiation pattern produced by a single foil or stack of foils is focused by optics to increase the intensity of the radiation at a distance from the conical radiator. 8 figs.

Lung Cancer Prevention

MedlinePlus

... is a risk factor for lung cancer. Atomic bomb radiation, radiation therapy , imaging tests , and radon are sources of radiation exposure: Atomic bomb radiation: Being exposed to radiation after an atomic ...

Excitation of parasitic waves in forward-wave amplifiers with weak guiding fields.

PubMed

Nusinovich, G S; Romero-Talamás, C A; Han, Y

2012-12-01

To produce high-power coherent electromagnetic radiation at frequencies from microwaves up to terahertz, the radiation sources should have interaction circuits of large cross sections, i.e., the sources should operate in high-order modes. In such devices, the excitation of higher-order parasitic modes near cutoff where the group velocity is small and, hence, start currents are low can be a serious problem. The problem is especially severe in the sources of coherent, phase-controlled radiation, i.e., the amplifiers or phase-locked oscillators. This problem was studied earlier [Nusinovich, Sinitsyn, and Antonsen, Phys. Rev. E 82, 046404 (2010)] for the case of electron focusing by strong guiding magnetic fields. For many applications it is desirable to minimize these focusing fields. Therefore in this paper we analyze the problem of excitation of parasitic modes near cutoff in forward-wave amplifiers with weak focusing fields. First, we study the large-signal operation of such a device with a signal wave only. Then, we analyze the self-excitation conditions of parasitic waves near cutoff in the presence of the signal wave. It is shown that the main effect is the suppression of the parasitic wave in large-signal regimes. At the same time, there is a region of device parameters where the presence of signal waves can enhance excitation of parasitic modes. The role of focusing fields in such effects is studied.

Integrated Plasma Control for Alternative Plasma Shape on EAST

NASA Astrophysics Data System (ADS)

Xiao, Bingjia

2017-10-01

To support long pulse plasma operation in high performance, a set of plasma control algorithms such as PEFIT real-time equilibrium reconstruction, radiation feedback, Beta and loop voltage feedback and quasi-snowflake shape f control have been implemented on EAST Plasma Control system (PCS) which was adapted from DIII-D PCS. PEFIT is a parallelized version of EFIT by using GPU with highest computation acceleration ratio up to 100 with respect to EFIT. It demonstrated high performance both in DIII-D data analysis and in the real-time shape control on EAST plasma either in normal or quasi-snowflake shape. Loop voltage has been successfully controlled by Low Hybrid Wave (LHW) while the plasma current is maintained by poloidal field coil set. Beta control has been also demonstrated by using LHW and it will be extended to other heating sources because the PCS interface is ready. Radiation feedback control has been achieved by Neon seeding by Super-Sonic Molecular Beam Injection (SMBI). For the plasma operation in quasi-snowflake, we have reached 20 s ELMy free high confinement non-inductive discharges with betap 2, H98 1.1 and plasma current 250 kA. EAST orals.

Thin-film spectroscopic sensor

DOEpatents

Burgess, Jr., Lloyd W.; Goldman, Don S.

1992-01-01

There is disclosed an integrated spectrometer for chemical analysis by evanescent electromagnetic radiation absorption in a reaction volume. The spectrometer comprises a noninteractive waveguide, a substrate, an entrance grating and an exit grating, an electromagnetic radiation source, and an electromagnetic radiation sensing device. There is further disclosed a chemical sensor to determine the pressure and concentration of a chemical species in a mixture comprising an interactive waveguide, a substrate, an entrance grating and an exit grating, an electromagnetic radiation source, and an electromagnetic radiation sensing device.

Air-coupled acoustic thermography for in-situ evaluation

NASA Technical Reports Server (NTRS)

Zalameda, Joseph N. (Inventor); Winfree, William P. (Inventor); Yost, William T. (Inventor)

2010-01-01

Acoustic thermography uses a housing configured for thermal, acoustic and infrared radiation shielding. For in-situ applications, the housing has an open side adapted to be sealingly coupled to a surface region of a structure such that an enclosed chamber filled with air is defined. One or more acoustic sources are positioned to direct acoustic waves through the air in the enclosed chamber and towards the surface region. To activate and control each acoustic source, a pulsed signal is applied thereto. An infrared imager focused on the surface region detects a thermal image of the surface region. A data capture device records the thermal image in synchronicity with each pulse of the pulsed signal such that a time series of thermal images is generated. For enhanced sensitivity and/or repeatability, sound and/or vibrations at the surface region can be used in feedback control of the pulsed signal applied to the acoustic sources.

Size-Tuned Plastic Flow Localization in Irradiated Materials at the Submicron Scale

NASA Astrophysics Data System (ADS)

Cui, Yinan; Po, Giacomo; Ghoniem, Nasr

2018-05-01

Three-dimensional discrete dislocation dynamics (3D-DDD) simulations reveal that, with reduction of sample size in the submicron regime, the mechanism of plastic flow localization in irradiated materials transitions from irradiation-controlled to an intrinsic dislocation source controlled. Furthermore, the spatial correlation of plastic deformation decreases due to weaker dislocation interactions and less frequent cross slip as the system size decreases, thus manifesting itself in thinner dislocation channels. A simple model of discrete dislocation source activation coupled with cross slip channel widening is developed to reproduce and physically explain this transition. In order to quantify the phenomenon of plastic flow localization, we introduce a "deformation localization index," with implications to the design of radiation-resistant materials.

1985 Particle Accelerator Conference: Accelerator Engineering and Technology, 11th, Vancouver, Canada, May 13-16, 1985, Proceedings

NASA Astrophysics Data System (ADS)

Strathdee, A.

1985-10-01

The topics discussed are related to high-energy accelerators and colliders, particle sources and electrostatic accelerators, controls, instrumentation and feedback, beam dynamics, low- and intermediate-energy circular accelerators and rings, RF and other acceleration systems, beam injection, extraction and transport, operations and safety, linear accelerators, applications of accelerators, radiation sources, superconducting supercolliders, new acceleration techniques, superconducting components, cryogenics, and vacuum. Accelerator and storage ring control systems are considered along with linear and nonlinear orbit theory, transverse and longitudinal instabilities and cures, beam cooling, injection and extraction orbit theory, high current dynamics, general beam dynamics, and medical and radioisotope applications. Attention is given to superconducting RF structures, magnet technology, superconducting magnets, and physics opportunities with relativistic heavy ion accelerators.

Laser-plasma extreme ultraviolet and soft X-ray sources based on a double stream gas puff target: interaction of the radiation pulses with matter

NASA Astrophysics Data System (ADS)

Bartnik, A.

2015-06-01

In this work a review of investigations concerning interaction of intense extreme ultraviolet (EUV) and soft X-ray (SXR) pulses with matter is presented. The investigations were performed using laser-produced plasma (LPP) EUV/SXR sources based on a double stream gas puff target. The sources are equipped with dedicated collectors allowing for efficient focusing of the EUV/SXR radiation pulses. Intense radiation in a wide spectral range, as well as a quasi-monochromatic radiation can be produced. In the paper different kinds of LPP EUV/SXR sources developed in the Institute of Optoelectronics, Military University of Technology are described. Radiation intensities delivered by the sources are sufficient for different kinds of interaction experiments including EUV/SXR induced ablation, surface treatment, EUV fluorescence or photoionized plasma creation. A brief review of the main results concerning this kind of experiments performed by author of the paper are presented. However, since the LPP sources cannot compete with large scale X-ray sources like synchrotrons, free electron lasers or high energy density plasma sources, it was indicated that some investigations not requiring extreme irradiation parameters can be performed using the small scale installations. Some results, especially concerning low temperature photoionized plasmas are very unique and could be hardly obtained using the large facilities.

Total-dose radiation effects data for semiconductor devices, volume 2

NASA Technical Reports Server (NTRS)

Price, W. E.; Martin, K. E.; Nichols, D. K.; Gauthier, M. K.; Brown, S. F.

1981-01-01

Total ionizing dose radiation test data on integrated circuits are analyzed. Tests were performed with the electron accelerator (Dynamitron) that provides a steady state 2.5 MeV electron beam. Some radiation exposures were made with a Cobalt-60 gamma ray source. The results obtained with the Cobalt-60 source are considered an approximate measure of the radiation damage that would be incurred by an equivalent dose of electrons.

Atomic physics research with second and third generation synchrotron light sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, B.M.

1990-10-01

This contribution to these proceedings is intended to provide an introduction and overview for other contributions on atomic (and related) physics research at existing and planned synchrotron light sources. The emphasis will be on research accomplishments and future opportunities, but a comparison will be given of operating characteristics for first, second, and third generation machines. First generation light sources were built to do research with the primary electron and positron beams, rather than with the synchrotron radiation itself. Second generation machines were specifically designed to be dedicated synchrotron-radiation facilities, with an emphasis on the use of bending-magnet radiation. The newmore » third generation light sources are being designed to optimize radiation from insertion devices, such as undulators and wigglers. Each generation of synchrotron light source offers useful capabilities for forefront research in atomic physics and many other disciplines. 27 refs., 1 fig., 3 tabs.« less

New blackbody calibration source for low temperatures from -20 C to +350 C

NASA Astrophysics Data System (ADS)

Mester, Ulrich; Winter, Peter

2001-03-01

Calibration procedures for infrared thermometers and thermal imaging systems require radiation sources of precisely known radiation properties. In the physical absence of an ideal Planck's radiator, the German Committee VDI/VDE-GMA FA 2.51, 'Applied Radiation Thermometry', agreed upon desirable specifications and limiting parameters for a blackbody calibration source with a temperature range from -20 degree(s)C to +350 degree(s)C, a spectral range from 2 to 15 microns, an emissivity greater than 0.999 and a useful source aperture of 60 mm, among others. As a result of the subsequent design and development performed with the support of the laboratory '7.31 Thermometry' of the German national institute of natural and engineering sciences (PTB), the Mester ME20 Blackbody Calibration Source is presented. The ME20 meets or exceeds all of the specifications formulated by the VDI/VDE committee.

Analysis of Radiation Impact on White Mice through Radiation Dose Mapping in Medical Physics Laboratory

NASA Astrophysics Data System (ADS)

Sutikno, Madnasri; Susilo; Arya Wijayanti, Riza

2016-08-01

A study about X-ray radiation impact on the white mice through radiation dose mapping in Medical Physic Laboratory is already done. The purpose of this research is to determine the minimum distance of radiologist to X-ray instrument through treatment on the white mice. The radiation exposure doses are measured on the some points in the distance from radiation source between 30 cm up to 80 with interval of 30 cm. The impact of radiation exposure on the white mice and the effects of radiation measurement in different directions are investigated. It is founded that minimum distance of radiation worker to radiation source is 180 cm and X-ray has decreased leukocyte number and haemoglobin and has increased thrombocyte number in the blood of white mice.

Effect of Different Solar Radiation Data Sources on the Variation of Techno-Economic Feasibility of PV Power System

NASA Astrophysics Data System (ADS)

Alghoul, M. A.; Ali, Amer; Kannanaikal, F. V.; Amin, N.; Aljaafar, A. A.; Kadhim, Mohammed; Sopian, K.

2017-11-01

The aim of this study is to evaluate the variation in techno-economic feasibility of PV power system under different data sources of solar radiation. HOMER simulation tool is used to predict the techno-economic feasibility parameters of PV power system in Baghdad city, Iraq located at (33.3128° N, 44.3615° E) as a case study. Four data sources of solar radiation, different annual capacity shortages percentage (0, 2.5, 5, and 7.5), and wide range of daily load profile (10-100 kWh/day) are implemented. The analyzed parameters of the techno-economic feasibility are COE (/kWh), PV array power capacity (kW), PV electrical production (kWh/year), No. of batteries and battery lifetime (year). The main results of the study revealed the followings: (1) solar radiation from different data sources caused observed to significant variation in the values of the techno-economic feasibility parameters; therefore, careful attention must be paid to ensure the use of an accurate solar input data; (2) Average solar radiation from different data sources can be recommended as a reasonable input data; (3) it is observed that as the size and of PV power system increases, the effect of different data sources of solar radiation increases and causes significant variation in the values of the techno-economic feasibility parameters.

Excitation of a buried magmatic pipe: A seismic source model for volcanic tremor

NASA Astrophysics Data System (ADS)

Chouet, Bernard

1985-02-01

Recent observations of seismic events at various volcanoes suggest that harmonic tremor results from the sustained occurrence of so-called long-period or low-frequency events. Accordingly, we can view the long-period volcanic event as the elementary process of tremor and interpret it as the impulse response of the tremor-generating system. We present a seismic model in which the source of tremor is the acoustic resonance of a fluid-filled volcanic pipe triggered by excess gas pressure. The model consists of three elements, namely, a triggering mechanism, a resonator, and a radiator. For simplicity, we assume a hemispherical trigger, cylindrial resonator, and circular radiator set in a vertical configuration with the trigger capping the top of the pipe and the disk-shaped radiator shutting off its bottom. Considering the simple case of a source buried in a homogeneous half space, we then apply the discrete wave number method to obtain a complete representation of the ground motion response at near and intermediate distances. The results demonstrate that the displacement attributed to the pipe dominates the near-field motion, while that due to the disk is representative of the intermediate and far fields. The trigger itself has a smaller contribution, mainly limited to the field in the proximity of the source. The characteristics displayed by the free surface response evolve from a strong impulsive signature in the immediate vicinity of the epicenter to a well-developed harmonic wave train dominated by Rayleigh waves at larger distances. No clear shear arrival can be detected in the synthetic seismograms. The displacement spectrum reflects the organ-pipe modes of the conduit, and the bandwidth associated with the dominant spectral peak of motion is controlled by the combined losses due to viscous attenuation in the fluid and elastic radiation into the solid. In the case of the cylindrical magma column considered, the radiation loss is proportional to the square of the pipe radius, while the loss related to viscous damping is inversely proportional to the same factor, indicating that the relative importance of the two loss mechanisms is critically dependent on the geometry of the magma reservoir. The relative importance of the pipe and disk elements, likewise, is a function of the conduit cross section. This suggests the possibility of determining the geometry of the source as well as the radiation loss and in situ magma viscosity from a comparison of near- and far-field observations.

Experience With Laser Safety In The USA--A Review

NASA Astrophysics Data System (ADS)

Sliney, David H.

1986-10-01

Following several research programs in the 1960's aimed at studying the adverse biological effects of lasers and other optical radiation sources, laser occupational exposure limits were set and general safety standards were developed. Today, the experience from laser accidents and the development of new lasers and new applications have altered the format of the exposure limits and the safety procedures. It is critically important to distinguish between different biological injury mechanisms. The biological effects of ultraviolet radiation upon the skin and eye are additive over a period of at least one workday, and require different safety procedures. The scattered UV irradiance from excimer lasers may be quite hazardous, depending upon wavelength and action spectra. Since laser technology is young, the exposure of an individual in natural sunlight must be studied to evaluate the potential for chronic effects. The safety measures necessary in the use of lasers depend upon a hazard evaluation. The appropriate control measures and alternate means of enclosure, baffling, and operational control measures are presented. Present laser safety standards are explained briefly. Eye protective techniques and eyewear are considered for a variety of sources. The optical properties of enclosure materials are also discussed.

Radiation as a Risk Factor for Cardiovascular Disease

PubMed Central

Moulder, John E.; Hopewell, John W.

2011-01-01

Abstract Humans are continually exposed to ionizing radiation from terrestrial sources. The two major contributors to radiation exposure of the U.S. population are ubiquitous background radiation and medical exposure of patients. From the early 1980s to 2006, the average dose per individual in the United States for all sources of radiation increased by a factor of 1.7–6.2 mSv, with this increase due to the growth of medical imaging procedures. Radiation can place individuals at an increased risk of developing cardiovascular disease. Excess risk of cardiovascular disease occurs a long time after exposure to lower doses of radiation as demonstrated in Japanese atomic bomb survivors. This review examines sources of radiation (atomic bombs, radiation accidents, radiological terrorism, cancer treatment, space exploration, radiosurgery for cardiac arrhythmia, and computed tomography) and the risk for developing cardiovascular disease. The evidence presented suggests an association between cardiovascular disease and exposure to low-to-moderate levels of radiation, as well as the well-known association at high doses. Studies are needed to define the extent that diagnostic and therapeutic radiation results in increased risk factors for cardiovascular disease, to understand the mechanisms involved, and to develop strategies to mitigate or treat radiation-induced cardiovascular disease. Antioxid. Redox Signal. 15, 1945–1956. PMID:21091078

Bacterial Survival under Extreme UV Radiation: A Comparative Proteomics Study of Rhodobacter sp., Isolated from High Altitude Wetlands in Chile

PubMed Central

Pérez, Vilma; Hengst, Martha; Kurte, Lenka; Dorador, Cristina; Jeffrey, Wade H.; Wattiez, Ruddy; Molina, Veronica; Matallana-Surget, Sabine

2017-01-01

Salar de Huasco, defined as a polyextreme environment, is a high altitude saline wetland in the Chilean Altiplano (3800 m.a.s.l.), permanently exposed to the highest solar radiation doses registered in the world. We present here the first comparative proteomics study of a photoheterotrophic bacterium, Rhodobacter sp., isolated from this remote and hostile habitat. We developed an innovative experimental approach using different sources of radiation (in situ sunlight and UVB lamps), cut-off filters (Mylar, Lee filters) and a high-throughput, label-free quantitative proteomics method to comprehensively analyze the effect of seven spectral bands on protein regulation. A hierarchical cluster analysis of 40 common proteins revealed that all conditions containing the most damaging UVB radiation induced similar pattern of protein regulation compared with UVA and visible light spectral bands. Moreover, it appeared that the cellular adaptation of Rhodobacter sp. to osmotic stress encountered in the hypersaline environment from which it was originally isolated, might further a higher resistance to damaging UV radiation. Indeed, proteins involved in the synthesis and transport of key osmoprotectants, such as glycine betaine and inositol, were found in very high abundance under UV radiation compared to the dark control, suggesting the function of osmolytes as efficient reactive oxygen scavengers. Our study also revealed a RecA-independent response and a tightly regulated network of protein quality control involving proteases and chaperones to selectively degrade misfolded and/or damaged proteins. PMID:28694800

Optical Coating Performance for Heat Reflectors of the JWST-ISIM Electronic Component

NASA Technical Reports Server (NTRS)

Rashford, Robert A.; Perrygo, Charles M.; Garrison, Matthew B.; White, Bryant K.; Threat, Felix T.; Quijada, Manuel A.; Jeans, James W.; Huber, Frank K.; Bousquet, Robert R.; Shaw, Dave

2011-01-01

A document discusses a thermal radiator design consisting of lightweight composite materials and low-emittance metal coatings for use on the James Webb Space Telescope (JWST) structure. The structure will have a Thermal Subsystem unit to provide passive cooling to the Integrated Science Instrument Module (ISIM) control electronics. The ISIM, in the JWST observatory, is the platform that provides the mounting surfaces for the instrument control electronics. Dissipating the control electronic generated-heat away from JWST is of paramount importance so that the spacecraft s own heat does not interfere with the infrared-light gathering of distant cosmic sources. The need to have lateral control in the emission direction of the IEC (ISIM Electronics Compartment) radiators led to the development of a directional baffle design that uses multiple curved mirrorlike surfaces. This concept started out from the so-called Winston non-imaging optical concentrators that use opposing parabolic reflector surfaces, where each parabola has its focus at the opposite edge of the exit aperture. For this reason they are often known as compound parabolic concentrators or CPCs. This radiator system with the circular section was chosen for the IEC reflectors because it offers two advantages over other designs. The first is that the area of the reflector strips for a given radiator area is less, which results in a lower mass baffle assembly. Secondly, the fraction of energy emitted by the radiator strips and subsequently reflected by the baffle is less. These fewer reflections reduced the amount of energy that is absorbed and eventually re-emitted, typically in a direction outside the design emission range angle. A baffle frame holds the mirrors in position above a radiator panel on the IEC. Together, these will direct the majority of the heat from the IEC above the sunshield away towards empty space.

Mossbauer spectrometer radiation detector

NASA Technical Reports Server (NTRS)

Singh, J. J. (Inventor)

1973-01-01

A Mossbauer spectrometer with high efficiencies in both transmission and backscattering techniques is described. The device contains a sodium iodide crystal for detecting radiation caused by the Mossbauer effect, and two photomultipliers to collect the radiation detected by the crystal. When used in the transmission technique, the sample or scatterer is placed between the incident radiation source and the detector. When used in a backscattering technique, the detector is placed between the incident radiation source and the sample of scatterer such that the incident radiation will pass through a hole in the crystal and strike the sample. Diagrams of the instrument are provided.

Fan Noise Prediction System Development: Source/Radiation Field Coupling and Workstation Conversion for the Acoustic Radiation Code

NASA Technical Reports Server (NTRS)

Meyer, H. D.

1993-01-01

The Acoustic Radiation Code (ARC) is a finite element program used on the IBM mainframe to predict far-field acoustic radiation from a turbofan engine inlet. In this report, requirements for developers of internal aerodynamic codes regarding use of their program output an input for the ARC are discussed. More specifically, the particular input needed from the Bolt, Beranek and Newman/Pratt and Whitney (turbofan source noise generation) Code (BBN/PWC) is described. In a separate analysis, a method of coupling the source and radiation models, that recognizes waves crossing the interface in both directions, has been derived. A preliminary version of the coupled code has been developed and used for initial evaluation of coupling issues. Results thus far have shown that reflection from the inlet is sufficient to indicate that full coupling of the source and radiation fields is needed for accurate noise predictions ' Also, for this contract, the ARC has been modified for use on the Sun and Silicon Graphics Iris UNIX workstations. Changes and additions involved in this effort are described in an appendix.

Terrestrial Myriametric Radio Burst Observed by IMAGE and Geotail Satellites

NASA Technical Reports Server (NTRS)

Fung, Shing F.; Hashimoto, KoZo; Kojima, Hirotsugu; Boardson, Scott A.; Garcia, Leonard N.; Matsumoto, Hiroshi; Green, James L.; Reinisch, Bodo W.

2013-01-01

We report the simultaneous detection of a terrestrial myriametric radio burst (TMRB) by IMAGE and Geotail on 19 August 2001. The TMRB was confined in time (0830-1006 UT) and frequency (12-50kHz). Comparisons with all known nonthermal myriametric radiation components reveal that the TMRB might be a distinct radiation with a source that is unrelated to the previously known radiation. Considerations of beaming from spin-modulation analysis and observing satellite and source locations suggest that the TMRB may have a fan beamlike radiation pattern emitted by a discrete, dayside source located along the poleward edge of magnetospheric cusp field lines. TMRB responsiveness to IMF Bz and By orientations suggests that a possible source of the TMRB could be due to dayside magnetic reconnection instigated by northward interplanetary field condition.

On the role of the radiation directivity in noise reduction for STOL aircraft.

NASA Technical Reports Server (NTRS)

Gruschka, H. D.

1972-01-01

The radiation characteristics of distributed randomly fluctuating acoustic sources when shielded by finite surfaces are discussed briefly. A number of model tests using loudspeakers as artificial noise sources with a given broadband power density spectrum are used to demonstrate the effectiveness of reducing the radiated noise intensity in certain directions due to shielding. In the lateral direction of the source array noise reductions of 12 dB are observed with relatively small shields. The same shields reduce the backward radiation by approximately 20 dB. With the results obtained in these acoustic model tests the potentials of jet noise reduction of jet flap propulsion systems applicable in future STOL aircraft are discussed. The jet flap configuration as a complex aerodynamic noise source is described briefly.

Prospects for Practical Applications of a Discharge Chemical HF Laser as a Coherent Source for IR Holography

NASA Astrophysics Data System (ADS)

Fedotov, O. G.; Fomin, V. M.

2018-02-01

Preliminary experimental results on recording of phase and amplitude holograms using the radiation of electric-discharge HF lasers are presented, and prospects for applications of such lasers in diagnostics of various objects are discussed. It is shown that lasers with homogeneous working medium may generate coherent radiation with a coherence length of greater than 6 m in the absence of mode selection. Methods for control of spatial distribution of electron concentration in excimer and discharge chemical HF (DF) lasers and distributions of the main combustible components are considered. Deposition of holographic identification marks on artworks is studied.

Frequency conversion system

NASA Technical Reports Server (NTRS)

Sanders, Steven (Inventor); Waarts, Robert G. (Inventor)

2001-01-01

A frequency conversion system comprises first and second gain sources providing first and second frequency radiation outputs where the second gain source receives as input the output of the first gain source and, further, the second gain source comprises a Raman or Brillouin gain fiber for wave shifting a portion of the radiation of the first frequency output into second frequency radiation output to provided a combined output of first and second frequencies. Powers are gain enhanced by the addition of a rare earth amplifier or oscillator, or a Raman/Brillouin amplifier or oscillator between the high power source and the NFM device. Further, polarization conversion using Raman or Brillouin wavelength shifting is provided to optimize frequency conversion efficiency in the NFM device.

Radiation source with shaped emission

DOEpatents

Kubiak, Glenn D.; Sweatt, William C.

2003-05-13

Employing a source of radiation, such as an electric discharge source, that is equipped with a capillary region configured into some predetermined shape, such as an arc or slit, can significantly improve the amount of flux delivered to the lithographic wafers while maintaining high efficiency. The source is particularly suited for photolithography systems that employs a ringfield camera. The invention permits the condenser which delivers critical illumination to the reticle to be simplified from five or more reflective elements to a total of three or four reflective elements thereby increasing condenser efficiency. It maximizes the flux delivered and maintains a high coupling efficiency. This architecture couples EUV radiation from the discharge source into a ring field lithography camera.

High resolution x-ray and gamma ray imaging using diffraction lenses with mechanically bent crystals

DOEpatents

Smither, Robert K [Hinsdale, IL

2008-12-23

A method for high spatial resolution imaging of a plurality of sources of x-ray and gamma-ray radiation is provided. High quality mechanically bent diffracting crystals of 0.1 mm radial width are used for focusing the radiation and directing the radiation to an array of detectors which is used for analyzing their addition to collect data as to the location of the source of radiation. A computer is used for converting the data to an image. The invention also provides for the use of a multi-component high resolution detector array and for narrow source and detector apertures.

Exposure Dose Reconstruction from EPR Spectra of Tooth Enamel Exposed to the Combined Effect of X-rays and Gamma Radiation

NASA Astrophysics Data System (ADS)

Kirillov, V. A.; Kuchuro, J. I.

2014-09-01

We have used EPR dosimetry on tooth enamel to show that the combined effect of x-rays with effective energy 34 keV and gamma radiation with average energy 1250 keV leads to a significant increase in the reconstructed absorbed dose compared with the applied dose from a gamma source or from an x-ray source or from both sources of electromagnetic radiation. In simulation experiments, we develop an approach to estimating the contribution of diagnostic x-rays to the exposure dose formed in the tooth enamel by the combined effect of x-rays and gamma radiation.

Lightning electromagnetics

NASA Technical Reports Server (NTRS)

Wahid, Parveen

1995-01-01

This project involved the determination of the effective radiated power of lightning sources and the polarization of the radiating source. This requires the computation of the antenna patterns at all the LDAR site receiving antennas. The known radiation patterns and RF signal levels measured at the antennas will be used to determine the effective radiated power of the lightning source. The azimuth and elevation patterns of the antennas in the LDAR system were computed using flight test data that was gathered specifically for this purpose. The results presented in this report deal with the azimuth patterns for all the antennas and the elevation patterns for three of the seven sites.

The international atom: evolution of radiation control programs.

PubMed

Bradley, F J

2002-07-01

Under the Atoms for Peace program, Turkey received a one MWt swimming pool reactor in 1962 that initiated a health physics program for the reactor and a Radiation Control Program (RCP) for the country's use of ionizing radiation. Today, over 13,000 radiation workers, concentrated in the medical field, provide improved medical care with 6,200 x-ray units, including 494 CAT scanners, 222 radioimmunoassay (RIA) labs and 42 radiotherapy centers. Industry has a large stake in the safe use of ionizing radiation with over 1,200 x-ray and gamma radiography and fluoroscopic units, 2,500 gauges in automated process control and five irradiators. A 48-person RCP staff oversees this expanded radiation use. One incident involving a spent 3.3 TBq (88 Ci) 60Co source resulted in 10 overexposures but no fatalities. Taiwan received a 1.6 MWt swimming pool reactor in 1961 and rapidly applied nuclear technology to the medical and industrial fields. Today, there are approximately 24,000 licensed radiation workers in nuclear power field, industry, medicine and academia. Four BWRs and two PWRs supply about 25% of the island's electrical power needs. One traumatic event galvanized the RCP when an undetermined amount of 60Co was accidentally incorporated into reinforcing bars, which in turn were incorporated into residential and commercial buildings. Public exposures were estimated to range up to 15 mSv (1.3 rem) per annum. There were no reported ill effects, except possibly psychological, to date. The RCP now has instituted stringent control measures to ensure radiation-free dwellings and work places. Albania's RCP is described as it evolved since 1972. Regulations were promulgated which followed the IAEA Basic Safety Standards of that era. With 525 licenses and 600 radiation workers, the problem was not in the regulations per se but in their enforcement. The IAEA helped to upgrade the RCP as the economy evolved from one that was centrally planned economy to a free market economy. As this transition takes place, public radiation exposures in the medical field will continue to be high until the old x-ray equipment is phased out. A small conscientious health physics staff works with limited resources to keep radiation exposures at acceptable levels. These three country RCPs, as they have evolved, have some commonality. Today, all radiation installations are licensed, both for radioactive material and x-ray equipment. Radiation workers are individually licensed or registered. All RCPs have, or are striving to have, their radiation regulations conform to ICRP 60 recommendations as spelled out in the Basic Safety Standard (1996). Finally, all three countries have as yet to find a permanent solution for their radioactive waste.

Data Fusion for a Vision-Radiological System for Source Tracking and Discovery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Enqvist, Andreas; Koppal, Sanjeev

2015-07-01

A multidisciplinary approach to allow the tracking of the movement of radioactive sources by fusing data from multiple radiological and visual sensors is under development. The goal is to improve the ability to detect, locate, track and identify nuclear/radiological threats. The key concept is that such widely available visual and depth sensors can impact radiological detection, since the intensity fall-off in the count rate can be correlated to movement in three dimensions. To enable this, we pose an important question; what is the right combination of sensing modalities and vision algorithms that can best compliment a radiological sensor, for themore » purpose of detection and tracking of radioactive material? Similarly what is the best radiation detection methods and unfolding algorithms suited for data fusion with tracking data? Data fusion of multi-sensor data for radiation detection have seen some interesting developments lately. Significant examples include intelligent radiation sensor systems (IRSS), which are based on larger numbers of distributed similar or identical radiation sensors coupled with position data for network capable to detect and locate radiation source. Other developments are gamma-ray imaging systems based on Compton scatter in segmented detector arrays. Similar developments using coded apertures or scatter cameras for neutrons have recently occurred. The main limitation of such systems is not so much in their capability but rather in their complexity and cost which is prohibitive for large scale deployment. Presented here is a fusion system based on simple, low-cost computer vision and radiological sensors for tracking of multiple objects and identifying potential radiological materials being transported or shipped. The main focus of this work is the development on two separate calibration algorithms for characterizing the fused sensor system. The deviation from a simple inverse square-root fall-off of radiation intensity is explored and accounted for. In particular, the computer vision system enables a map of distance-dependence of the sources being tracked. Infrared, laser or stereoscopic vision sensors are all options for computer-vision implementation depending on interior vs exterior deployment, resolution desired and other factors. Similarly the radiation sensors will be focused on gamma-ray or neutron detection due to the long travel length and ability to penetrate even moderate shielding. There is a significant difference between the vision sensors and radiation sensors in the way the 'source' or signals are generated. A vision sensor needs an external light-source to illuminate the object and then detects the re-emitted illumination (or lack thereof). However, for a radiation detector, the radioactive material is the source itself. The only exception to this is the field of active interrogations where radiation is beamed into a material to entice new/additional radiation emission beyond what the material would emit spontaneously. The aspect of the nuclear material being the source itself means that all other objects in the environment are 'illuminated' or irradiated by the source. Most radiation will readily penetrate regular material, scatter in new directions or be absorbed. Thus if a radiation source is located near a larger object that object will in turn scatter some radiation that was initially emitted in a direction other than the direction of the radiation detector, this can add to the count rate that is observed. The effect of these scatter is a deviation from the traditional distance dependence of the radiation signal and is a key challenge that needs a combined system calibration solution and algorithms. Thus both an algebraic approach as well as a statistical approach have been developed and independently evaluated to investigate the sensitivity to this deviation from the simplified radiation fall-off as a function of distance. The resulting calibrated system algorithms are used and demonstrated in various laboratory scenarios, and later in realistic tracking scenarios. The selection and testing of radiological and computer-vision sensors for the additional specific scenarios will be the subject of ongoing and future work. (authors)« less

Ion-induced nuclear radiotherapy

DOEpatents

Horn, K.M.; Doyle, B.L.

1996-08-20

Ion-induced Nuclear Radiotherapy (INRT) is a technique for conducting radiosurgery and radiotherapy with a very high degree of control over the spatial extent of the irradiated volume and the delivered dose. Based upon the concept that low energy, ion induced atomic and nuclear reactions can be used to produce highly energetic reaction products at the site of a tumor, the INRT technique is implemented through the use of a conduit-needle or tube which conducts a low energy ion beam to a position above or within the intended treatment area. At the end of the conduit-needle or tube is a specially fabricated target which, only when struck by the ion beam, acts as a source of energetic radiation products. The inherent limitations in the energy, and therefore range, of the resulting reaction products limits the spatial extent of irradiation to a pre-defined volume about the point of reaction. Furthermore, since no damage is done to tissue outside this irradiated volume, the delivered dose may be made arbitrarily large. INRT may be used both as a point-source of radiation at the site of a small tumor, or as a topical bath of radiation to broad areas of diseased tissue. 25 figs.

Ion-induced nuclear radiotherapy

DOEpatents

Horn, Kevin M.; Doyle, Barney L.

1996-01-01

Ion-induced Nuclear Radiotherapy (INRT) is a technique for conducting radiosurgery and radiotherapy with a very high degree of control over the spatial extent of the irradiated volume and the delivered dose. Based upon the concept that low energy, ion induced atomic and nuclear reactions can be used to produce highly energetic reaction products at the site of a tumor, the INRT technique is implemented through the use of a conduit-needle or tube which conducts a low energy ion beam to a position above or within the intended treatment area. At the end of the conduit-needle or tube is a specially fabricated target which, only when struck by the ion beam, acts as a source of energetic radiation products. The inherent limitations in the energy, and therefore range, of the resulting reaction products limits the spatial extent of irradiation to a pre-defined volume about the point of reaction. Furthermore, since no damage is done to tissue outside this irradiated volume, the delivered dose may be made arbitrarily large. INRT may be used both as a point-source of radiation at the site of a small tumor, or as a topical bath of radiation to broad areas of diseased tissue.

An improved method for the calculation of Near-Field Acoustic Radiation Modes

NASA Astrophysics Data System (ADS)

Liu, Zu-Bin; Maury, Cédric

2016-02-01

Sensing and controlling Acoustic Radiation Modes (ARMs) in the near-field of vibrating structures is of great interest for broadband noise reduction or enhancement, as ARMs are velocity distributions defined over a vibrating surface, that independently and optimally contribute to the acoustic power in the acoustic field. But present methods only provide far-field ARMs (FFARMs) that are inadequate for the acoustic near-field problem. The Near-Field Acoustic Radiation Modes (NFARMs) are firstly studied with an improved numerical method, the Pressure-Velocity method, which rely on the eigen decomposition of the acoustic transfers between the vibrating source and a conformal observation surface, including sound pressure and velocity transfer matrices. The active and reactive parts of the sound power are separated and lead to the active and reactive ARMs. NFARMs are studied for a 2D baffled beam and for a 3D baffled plate, and so as differences between the NFARMS and the classical FFARMs. Comparisons of the NFARMs are analyzed when varying frequency and observation distance to the source. It is found that the efficiencies and shapes of the optimal active ARMs are independent on the distance while that of the reactive ones are distinctly related on.

15 CFR 908.3 - Activities subject to reporting.

Code of Federal Regulations, 2010 CFR

2010-01-01

... sources to influence convective circulation or to evaporate fog; (3) Modifying the solar radiation... artificial wind generation; or (8) Using lasers or other sources of electromagnetic radiation. (b) In...

49 CFR 176.150 - Radio and radar.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., unloaded, or handled, the responsible person must ensure that all sources of electromagnetic radiation such... are sensitive to electromagnetic radiation from external sources must be stowed at a safe distance...

49 CFR 176.150 - Radio and radar.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., unloaded, or handled, the responsible person must ensure that all sources of electromagnetic radiation such... are sensitive to electromagnetic radiation from external sources must be stowed at a safe distance...

49 CFR 176.150 - Radio and radar.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., unloaded, or handled, the responsible person must ensure that all sources of electromagnetic radiation such... are sensitive to electromagnetic radiation from external sources must be stowed at a safe distance...

49 CFR 176.150 - Radio and radar.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., unloaded, or handled, the responsible person must ensure that all sources of electromagnetic radiation such... are sensitive to electromagnetic radiation from external sources must be stowed at a safe distance...

49 CFR 176.150 - Radio and radar.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., unloaded, or handled, the responsible person must ensure that all sources of electromagnetic radiation such... are sensitive to electromagnetic radiation from external sources must be stowed at a safe distance...

Distributed Sensing for Quickest Change Detection of Point Radiation Sources

DTIC Science & Technology

2017-02-01

point occurs simultaneously at all sensor nodes, thus neglecting signal propagation delays. For nuclear radiation , the observation period, which is on... nuclear radiation using a sensor network,” in Homeland Security (HST), 2012 IEEE Conference on Technologies for. IEEE, 2012, pp. 648–653. [8] G. Lorden...Distributed Sensing for Quickest Change Detection of Point Radiation Sources Gene T. Whipps⋆† Emre Ertin† Randolph L. Moses† †The Ohio State

A compact radiation source for digital subtractive angiography

NASA Astrophysics Data System (ADS)

Wiedemann, H.; Baltay, M.; Carr, R.; Hernandez, M.; Lavender, W.

1994-08-01

Beam requirements for 33 keV radiation used in digital subtraction angiography have been established through extended experimentation first at Stanford and later at the National Synchrotron Light Source in Brookhaven. So far research and development of this medical procedure to image coronary blood vessels have been undertaken on large high energy electron storage rings. With progress in this diagnostic procedure, it is interesting to look for an optimum concept for providing a 33 keV radiation source which would fit into the environment of a hospital. A variety of competing effects and technologies to produce 33 keV radiation are available, but none of these processes provides the combination of sufficient photon flux and monochromaticity except for synchrotron radiation from an electron storage ring. The conceptual design of a compact storage ring optimized to fit into a hospital environment and producing sufficient 33 keV radiation for digital subtraction radiography will be discussed.

Recent advances in spacecraft thermal-control materials research.

NASA Technical Reports Server (NTRS)

Zerlaut, G. A.; Gilligan, J. E.; Gates, D. W.

1972-01-01

The state-of-the-art of spacecraft thermal-control materials technology has been significantly advanced during the past 4 years. Selective black coatings are discussed together with black paints, dielectric films on metal surfaces, and white radiator coatings. Criteria for the selection of thermal-control surfaces are considered, giving attention to prelaunch protection, the capability of being measured, reproducibility, simulator response, and aspects of a nonindigenous space environment. Progress in space simulation is related to vacuum technology, ultraviolet sources, solar wind simulation, and the production of protons. Advances have been made in the protection against space environmental effects, and in the development of thermal-control surfaces and pigments.

RADIATION SOURCES

DOEpatents

Brucer, M.H.

1958-04-15

A novel long-lived source of gamma radiation especially suitable for calibration purposes is described. The source of gamma radiation is denoted mock iodine131, which comprises a naixture of barium-133 and cesium-137. The barium and cesium are present in a barium-cesium ratio of approximately 5.7/1 to 14/1, uniformly dispersed in an ion exchange resin and a filter surrounding the resin comprised of a material of atomic number below approximately 51, and substantially 0.7 to 0.9 millimeter thick.

Measuring Radiofrequency and Microwave Radiation from Varying Signal Strengths

NASA Technical Reports Server (NTRS)

Davis, Bette; Gaul, W. C.

2007-01-01

This viewgraph presentation discusses the process of measuring radiofrequency and microwave radiation from various signal strengths. The topics include: 1) Limits and Guidelines; 2) Typical Variable Standard (IEEE) Frequency Dependent; 3) FCC Standard 47 CFR 1.1310; 4) Compliance Follows Unity Rule; 5) Multiple Sources Contribute; 6) Types of RF Signals; 7) Interfering Radiations; 8) Different Frequencies Different Powers; 9) Power Summing - Peak Power; 10) Contribution from Various Single Sources; 11) Total Power from Multiple Sources; 12) Are You Out of Compliance?; and 13) In Compliance.

Discharge source with gas curtain for protecting optics from particles

DOEpatents

Fornaciari, Neal R.; Kanouff, Michael P.

2004-03-30

A gas curtain device is employed to deflect debris that is generated by an extreme ultraviolet and soft x-ray radiation discharge source such as an electric discharge plasma source. The gas curtain device projects a stream of gas over the path of the radiation to deflect debris particles into a direction that is different from that of the path of the radiation. The gas curtain can be employed to prevent debris accumulation on the optics used in photolithography.

Poster - 11: Radiation barrier thickness calculations for the GammaPod

DOE Office of Scientific and Technical Information (OSTI.GOV)

La Russa, Daniel; Vandervoort, Eric; Wilkins, Davi

A consortium of radiotherapy centers in North America is in the process of evaluating a novel new {sup 60}Co teletherapy device, called the GammaPod™ (Xcision Medical Systems, Columbia Maryland), designed specifically for breast SBRT. The GammaPod consists of 36 collimated {sup 60}Co sources with a total activity of 4320 Ci. The sources are housed in a hemispherical source carrier that rotates during treatment to produce a cylindrically symmetric cone of primary beam spanning 16° – 54° degrees from the horizontal. This unique beam geometry presents challenges when designing or evaluating room shielding for the purposes of meeting regulatory requirements, andmore » for ensuring the safety of staff and the public in surrounding areas. Conventional methods for calculating radiation barrier thicknesses have been adapted so that barrier transmission factors for the GammaPod can be determined from a few relevant distances and characteristics of the primary beam. Simple formalisms have been determined for estimating shielding requirements for primary radiation (with a rotating and non-rotating source carrier), patient-scattered radiation, and leakage radiation. When making worst case assumptions, it was found that conventional barrier thicknesses associated with linac treatment suites are sufficient for shielding all sources of radiation from the GammaPod.« less

Consideration of the Protection Curtain's Shielding Ability after Identifying the Source of Scattered Radiation in the Angiography.

PubMed

Sato, Naoki; Fujibuchi, Toshioh; Toyoda, Takatoshi; Ishida, Takato; Ohura, Hiroki; Miyajima, Ryuichi; Orita, Shinichi; Sueyoshi, Tomonari

2017-06-15

To decrease radiation exposure to medical staff performing angiography, the dose distribution in the angiography was calculated in room using the particle and heavy ion transport code system (PHITS), which is based on Monte Carlo code, and the source of scattered radiation was confirmed using a tungsten sheet by considering the difference shielding performance among different sheet placements. Scattered radiation generated from a flat panel detector, X-ray tube and bed was calculated using the PHITS. In this experiment, the source of scattered radiation was identified as the phantom or acrylic window attached to the X-ray tube thus, a protection curtain was placed on the bed to shield against scattered radiation at low positions. There was an average difference of 20% between the measured and calculated values. The H*(10) value decreased after placing the sheet on the right side of the phantom. Thus, the curtain could decrease scattered radiation. © Crown copyright 2016.

Intrinsic Radiation Source Generation with the ISC Package: Data Comparisons and Benchmarking

DOE Office of Scientific and Technical Information (OSTI.GOV)

Solomon, Clell J. Jr.

The characterization of radioactive emissions from unstable isotopes (intrinsic radiation) is necessary for shielding and radiological-dose calculations from radioactive materials. While most radiation transport codes, e.g., MCNP [X-5 Monte Carlo Team, 2003], provide the capability to input user prescribed source definitions, such as radioactive emissions, they do not provide the capability to calculate the correct radioactive-source definition given the material compositions. Special modifications to MCNP have been developed in the past to allow the user to specify an intrinsic source, but these modification have not been implemented into the primary source base [Estes et al., 1988]. To facilitate the descriptionmore » of the intrinsic radiation source from a material with a specific composition, the Intrinsic Source Constructor library (LIBISC) and MCNP Intrinsic Source Constructor (MISC) utility have been written. The combination of LIBISC and MISC will be herein referred to as the ISC package. LIBISC is a statically linkable C++ library that provides the necessary functionality to construct the intrinsic-radiation source generated by a material. Furthermore, LIBISC provides the ability use different particle-emission databases, radioactive-decay databases, and natural-abundance databases allowing the user flexibility in the specification of the source, if one database is preferred over others. LIBISC also provides functionality for aging materials and producing a thick-target bremsstrahlung photon source approximation from the electron emissions. The MISC utility links to LIBISC and facilitates the description of intrinsic-radiation sources into a format directly usable with the MCNP transport code. Through a series of input keywords and arguments the MISC user can specify the material, age the material if desired, and produce a source description of the radioactive emissions from the material in an MCNP readable format. Further details of using the MISC utility can be obtained from the user guide [Solomon, 2012]. The remainder of this report presents a discussion of the databases available to LIBISC and MISC, a discussion of the models employed by LIBISC, a comparison of the thick-target bremsstrahlung model employed, a benchmark comparison to plutonium and depleted-uranium spheres, and a comparison of the available particle-emission databases.« less

ALARA efforts in nordic BWRs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ingemansson, T.; Lundgren, K.; Elkert, J.

1995-03-01

Some ALARA-related ABB Atom projects are currently under investigation. One of the projects has been ordered by the Swedish Radiation Protection Institute, and two others by the Nordic BWR utilities. The ultimate objective of the projects is to identify and develop methods to significantly decrease the future exposure levels in the Nordic BWRS. As 85% to 90% of the gamma radiation field in the Nordic BWRs originates from Co-60, the only way to significantly decrease the radiation doses is to effect Co and Co-60. The strategy to do this is to map the Co sources and estimate the source strengthmore » of Co from these sources, and to study the possibility to affect the release of Co-60 from the core surfaces and the uptake on system surfaces. Preliminary results indicate that corrosion/erosion of a relatively small number of Stellite-coated valves and/or dust from grinding of Stellite valves may significantly contribute to the Co input to the reactors. This can be seen from a high measured Co/Ni ratio in the feedwater and in the reactor water. If stainless steel is the only source of Co, the Co/Ni ratio would be less than 0.02 as the Co content in the steel is less than 0.2%. The Co/Ni ratio in the reactor water, however, is higher than 0.1, indicating that the major fraction of the Co originates from Stellite-coated valves. There are also other possible explanations for an increase of the radiation fields. The Co-60 inventory on the core surfaces increases approximately as the square of the burn-up level. If the burn-up is increased from 35 to 5 MWd/kgU, the Co-60 inventory on the core surfaces will be doubled. Also the effect on the behavior of Co-60 of different water chemistry and materials conditions is being investigated. Examples of areas studied are Fe and Zn injection, pH-control, and different forms of surface pre-treatments.« less

Microbial Activity Response to Solar Radiation across Contrasting Environmental Conditions in Salar de Huasco, Northern Chilean Altiplano.

PubMed

Hernández, Klaudia L; Yannicelli, Beatriz; Olsen, Lasse M; Dorador, Cristina; Menschel, Eduardo J; Molina, Verónica; Remonsellez, Francisco; Hengst, Martha B; Jeffrey, Wade H

2016-01-01

In high altitude environments, extreme levels of solar radiation and important differences of ionic concentrations over narrow spatial scales may modulate microbial activity. In Salar de Huasco, a high-altitude wetland in the Andean mountains, the high diversity of microbial communities has been characterized and associated with strong environmental variability. Communities that differed in light history and environmental conditions, such as nutrient concentrations and salinity from different spatial locations, were assessed for bacterial secondary production (BSP, 3 H-leucine incorporation) response from short-term exposures to solar radiation. We sampled during austral spring seven stations categorized as: (a) source stations, with recently emerged groundwater (no-previous solar exposure); (b) stream running water stations; (c) stations connected to source waters but far downstream from source points; and (d) isolated ponds disconnected from ground sources or streams with a longer isolation and solar exposure history. Very high values of 0.25 μE m -2 s -1 , 72 W m -2 and 12 W m -2 were measured for PAR, UVA, and UVB incident solar radiation, respectively. The environmental factors measured formed two groups of stations reflected by principal component analyses (near to groundwater sources and isolated systems) where isolated ponds had the highest BSP and microbial abundance (35 microalgae taxa, picoeukaryotes, nanoflagellates, and bacteria) plus higher salinities and PO 4 3- concentrations. BSP short-term response (4 h) to solar radiation was measured by 3 H-leucine incorporation under four different solar conditions: full sun, no UVB, PAR, and dark. Microbial communities established in waters with the longest surface exposure (e.g., isolated ponds) had the lowest BSP response to solar radiation treatments, and thus were likely best adapted to solar radiation exposure contrary to ground source waters. These results support our light history (solar exposure) hypothesis where the more isolated the community is from ground water sources, the better adapted it is to solar radiation. We suggest that factors other than solar radiation (e.g., salinity, PO 4 3- , NO 3 - ) are also important in determining microbial productivity in heterogeneous environments such as the Salar de Huasco.

Microbial Activity Response to Solar Radiation across Contrasting Environmental Conditions in Salar de Huasco, Northern Chilean Altiplano

PubMed Central

Hernández, Klaudia L.; Yannicelli, Beatriz; Olsen, Lasse M.; Dorador, Cristina; Menschel, Eduardo J.; Molina, Verónica; Remonsellez, Francisco; Hengst, Martha B.; Jeffrey, Wade H.

2016-01-01

In high altitude environments, extreme levels of solar radiation and important differences of ionic concentrations over narrow spatial scales may modulate microbial activity. In Salar de Huasco, a high-altitude wetland in the Andean mountains, the high diversity of microbial communities has been characterized and associated with strong environmental variability. Communities that differed in light history and environmental conditions, such as nutrient concentrations and salinity from different spatial locations, were assessed for bacterial secondary production (BSP, 3H-leucine incorporation) response from short-term exposures to solar radiation. We sampled during austral spring seven stations categorized as: (a) source stations, with recently emerged groundwater (no-previous solar exposure); (b) stream running water stations; (c) stations connected to source waters but far downstream from source points; and (d) isolated ponds disconnected from ground sources or streams with a longer isolation and solar exposure history. Very high values of 0.25 μE m-2 s-1, 72 W m-2 and 12 W m-2 were measured for PAR, UVA, and UVB incident solar radiation, respectively. The environmental factors measured formed two groups of stations reflected by principal component analyses (near to groundwater sources and isolated systems) where isolated ponds had the highest BSP and microbial abundance (35 microalgae taxa, picoeukaryotes, nanoflagellates, and bacteria) plus higher salinities and PO43- concentrations. BSP short-term response (4 h) to solar radiation was measured by 3H-leucine incorporation under four different solar conditions: full sun, no UVB, PAR, and dark. Microbial communities established in waters with the longest surface exposure (e.g., isolated ponds) had the lowest BSP response to solar radiation treatments, and thus were likely best adapted to solar radiation exposure contrary to ground source waters. These results support our light history (solar exposure) hypothesis where the more isolated the community is from ground water sources, the better adapted it is to solar radiation. We suggest that factors other than solar radiation (e.g., salinity, PO43-, NO3-) are also important in determining microbial productivity in heterogeneous environments such as the Salar de Huasco. PMID:27920763

VIEW OF BUILDING 126, LOOKING NORTH. BUILDING 126, THE SOURCE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW OF BUILDING 126, LOOKING NORTH. BUILDING 126, THE SOURCE CALIBRATION LABORATORY, WAS USED TO EXPOSE AND CALIBRATE RADIATION DETECTION DEVICES, INCLUDING THERMOLUMINESCENT DOSIMETERS, WORN BY EMPLOYEES TO DETECT RADIATION EXPOSURE - Rocky Flats Plant, Source Calibration Laboratory, Between Second & Third Streets & Central & Cedar Avenues, Golden, Jefferson County, CO

Novel method to control antenna currents based on theory of characteristic modes

NASA Astrophysics Data System (ADS)

Elghannai, Ezdeen Ahmed

Characteristic Mode Theory is one of the very few numerical methods that provide a great deal of physical insight because it allows us to determine the natural modes of the radiating structure. The key feature of these modes is that the total induced antenna current, input impedance/admittance and radiation pattern can be expressed as a linear weighted combination of individual modes. Using this decomposition method, it is possible to study the behavior of the individual modes, understand them and therefore control the antennas behavior; in other words, control the currents induced on the antenna structure. This dissertation advances the topic of antenna design by carefully controlling the antenna currents over the desired frequency band to achieve the desired performance specifications for a set of constraints. Here, a systematic method based on the Theory of Characteristic Modes (CM) and lumped reactive loading to achieve the goal of current control is developed. The lumped reactive loads are determined based on the desired behavior of the antenna currents. This technique can also be used to impedance match the antenna to the source/generator connected to it. The technique is much more general than the traditional impedance matching. Generally, the reactive loads that properly control the currents exhibit a combination of Foster and non-Foster behavior. The former can be implemented with lumped passive reactive components, while the latter can be implemented with lumped non-Foster circuits (NFC). The concept of current control is applied to design antennas with a wide band (impedance/pattern) behavior using reactive loads. We successfully applied this novel technique to design multi band and wide band antennas for wireless applications. The technique was developed to match the antenna to resistive and/or complex source impedance and control the radiation pattern at these frequency bands, considering size and volume constraints. A wide band patch antenna was achieved using the developed technique. In addition, the technique was applied to multi band wire less Universal Serial Bus (USB) dongle antenna that serves for WLAN IEEE 802.11 a/b/g/n band applications and Radio Frequency Identification (RFID) tag antenna for 915MHz band applications with superior performance compared to previous published results. This dissertation also discusses the total Q of an antenna from the CM standpoint. A new expression as well as additional physical information about each mode's individual contribution to the total antenna Q are provided. Finally, the theory is used to an analyze the antenna in both radiation and/or scattering modes. In the antenna scattering mode, the field scattered by an antenna contains a component that is the short circuit scattered field, and a second component that is proportional to the radiation field. In this dissertation, an analytical study of this phenomena from the CM standpoint is performed aiming to shed some light on antenna scattering phenomenon where additional physical insight is obtained and thus used to reach desire results.

Radiative flux from a planar multiple point source within a cylindrical enclosure reaching a coaxial circular plane

NASA Astrophysics Data System (ADS)

Tryka, Stanislaw

2007-04-01

A general formula and some special integral formulas were presented for calculating radiative fluxes incident on a circular plane from a planar multiple point source within a coaxial cylindrical enclosure perpendicular to the source. These formula were obtained for radiation propagating in a homogeneous isotropic medium assuming that the lateral surface of the enclosure completely absorbs the incident radiation. Exemplary results were computed numerically and illustrated with three-dimensional surface plots. The formulas presented are suitable for determining fluxes of radiation reaching planar circular detectors, collectors or other planar circular elements from systems of laser diodes, light emitting diodes and fiber lamps within cylindrical enclosures, as well as small biological emitters (bacteria, fungi, yeast, etc.) distributed on planar bases of open nontransparent cylindrical containers.

Non-destructive component separation using infrared radiant energy

DOEpatents

Simandl, Ronald F [Knoxville, TN; Russell, Steven W [Knoxville, TN; Holt, Jerrid S [Knoxville, TN; Brown, John D [Harriman, TN

2011-03-01

A method for separating a first component and a second component from one another at an adhesive bond interface between the first component and second component. Typically the method involves irradiating the first component with infrared radiation from a source that radiates substantially only short wavelengths until the adhesive bond is destabilized, and then separating the first component and the second component from one another. In some embodiments an assembly of components to be debonded is placed inside an enclosure and the assembly is illuminated from an IR source that is external to the enclosure. In some embodiments an assembly of components to be debonded is simultaneously irradiated by a multi-planar array of IR sources. Often the IR radiation is unidirectional. In some embodiments the IR radiation is narrow-band short wavelength infrared radiation.

Measurement of an image jitter of an extended incoherent radiation source

NASA Astrophysics Data System (ADS)

Lukin, V. P.; Nosov, V. V.

2017-06-01

A scheme of an image jitter measuring device, which uses an extended incoherent source as a radiation source, is presented. The efficiency of the measuring device is analysed analytically and numerically in order to justify the operation of the adaptive optical system that does not require special creation or formation of a reference source. The features of the formed image of incoherent radiation are considered, in particular from the point of view of its possible application for measuring the phase fluctuations of optical waves propagating in a turbulent atmosphere (the adaptive system monitors the image of a self-luminous object illuminated by extraneous sources). The possibility of utilising a Shack-Hartmann wavefront sensor in adaptive systems using the image of an arbitrary object (or its fragment) as a reference source is shown.

Regional Modeling of Dust Mass Balance and Radiative Forcing over East Asia using WRF-Chem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Siyu; Zhao, Chun; Qian, Yun

The Weather Research and Forecasting model with Chemistry (WRF-Chem) is used to investigate the seasonal and annual variations of mineral dust over East Asia during 2007-2011, with a focus on the dust mass balance and radiative forcing. A variety of measurements from in-stu and satellite observations have been used to evaluate simulation results. Generally, WRF-Chem reproduces not only the column variability but also the vertical profile and size distribution of mineral dust over and near the dust source regions of East Asia. We investigate the dust lifecycle and the factors that control the seasonal and spatial variations of dust massmore » balance and radiative forcing over the seven sub-regions of East Asia, i.e. source regions, the Tibetan Plateau, Northern China, Southern China, the ocean outflow region, and Korea-Japan regions. Results show that, over the source regions, transport and dry deposition are the two dominant sinks. Transport contributes to ~30% of the dust sink over the source regions. Dust results in a surface cooling of up to -14 and -10 W m-2, atmospheric warming of up to 20 and 15 W m-2, and TOA cooling of -5 and -8 W m-2 over the two major dust source regions of East Asia, respectively. Over the Tibetan Plateau, transport is the dominant source with a peak in summer. Over identified outflow regions, maximum dust mass loading in spring is contributed by the transport. Dry and wet depositions are the comparably dominant sinks, but wet deposition is larger than dry deposition over the Korea-Japan region, particularly in spring (70% versus 30%). The WRF-Chem simulations can generally capture the measured features of dust aerosols and its radaitve properties and dust mass balance over East Asia, which provides confidence for use in further investigation of dust impact on climate over East Asia.« less

Spherical harmonic analysis of the sound radiation from omnidirectional loudspeaker arrays

NASA Astrophysics Data System (ADS)

Pasqual, A. M.

2014-09-01

Omnidirectional sound sources are widely used in room acoustics. These devices are made up of loudspeakers mounted on a spherical or polyhedral cabinet, where the dodecahedral shape prevails. Although such electroacoustic sources have been made readily available to acousticians by many manufacturers, an in-depth investigation of their vibroacoustic behavior has not been provided yet. In order to fulfill this lack, this paper presents a theoretical study of the sound radiation from omnidirectional loudspeaker arrays, which is carried out by using a mathematical model based on the spherical harmonic analysis. Eight different loudspeaker arrangements on the sphere are considered: the well-known five Platonic solid layouts and three extremal system layouts. The latter possess useful properties for spherical loudspeaker arrays used as directivity controlled sound sources, so that these layouts are included here in order to investigate whether or not they could be of interest as omnidirectional sources as well. It is shown through a comparative analysis that the dodecahedral array leads to the lowest error in producing an omnidirectional sound field and to the highest acoustic power, which corroborates the prevalence of such a layout. In addition, if a source with less than 12 loudspeakers is required, it is shown that tetrahedra or hexahedra can be used alternatively, whereas the extremal system layouts are not interesting choices for omnidirectional loudspeaker arrays.

Time-Resolved Emission Spectroscopy of Field Reversed Configuration Thruster

DTIC Science & Technology

2016-08-31

radiation Collection Optics to 600um fiber Source: Scharer Research Group Source: PEARL 1. Acquire Spectrum 2. Compare to Collisional‐Radiative Model ( CRM ...calibration (deuterium lamp) • Obtain Argon FRC data and use Collisional Radiative Model ( CRM ) to extract plasma properties • Apply knowledge to improve FRC

Using Stellar Spectra to Illustrate Thermal Radiation Laws

ERIC Educational Resources Information Center

Kaltcheva, N. T.; Pritzl, B. J.

2018-01-01

Stars are point-source emitters that are the closest to the definition of a blackbody in comparison to all other similar sources of radiation found in nature. Existing libraries on stellar spectra are thus a valuable resource that can be used to introduce the laws of thermal radiation in a classroom setting. In this article we briefly describe…

Search for Artificial Stellar Sources of Infrared Radiation.

PubMed

Dyson, F J

1960-06-03

If extraterrestrial intelligent beings exist and have reached a high level of technical development, one by-product of their energy metabolism is likely to be the large-scale conversion of starlight into far-infrared radiation. It is proposed that a search for sources of infrared radiation should accompany the recently initiated search for interstellar radio communications.

Exotic X-ray Sources from Intermediate Energy Electron Beams

NASA Astrophysics Data System (ADS)

Chouffani, K.; Wells, D.; Harmon, F.; Jones, J. L.; Lancaster, G.

2003-08-01

High intensity x-ray beams are used in a wide variety of applications in solid-state physics, medicine, biology and material sciences. Synchrotron radiation (SR) is currently the primary, high-quality x-ray source that satisfies both brilliance and tunability. The high cost, large size and low x-ray energies of SR facilities, however, are serious limitations. Alternatively, "novel" x-ray sources are now possible due to new small linear accelerator (LINAC) technology, such as improved beam emittance, low background, sub-Picosecond beam pulses, high beam stability and higher repetition rate. These sources all stem from processes that produce Radiation from relativistic Electron beams in (crystalline) Periodic Structures (REPS), or the periodic "structure" of laser light. REPS x-ray sources are serious candidates for bright, compact, portable, monochromatic, and tunable x-ray sources with varying degrees of polarization and coherence. Despite the discovery and early research into these sources over the past 25 years, these sources are still in their infancy. Experimental and theoretical research are still urgently needed to answer fundamental questions about the practical and ultimate limits of their brightness, mono-chromaticity etc. We present experimental results and theoretical comparisons for three exotic REPS sources. These are Laser-Compton Scattering (LCS), Channeling Radiation (CR) and Parametric X-Radiation (PXR).

Method and Apparatus for Accurately Calibrating a Spectrometer

NASA Technical Reports Server (NTRS)

Youngquist, Robert C. (Inventor); Simmons, Stephen M. (Inventor)

2013-01-01

A calibration assembly for a spectrometer is provided. The assembly includes a spectrometer having n detector elements, where each detector element is assigned a predetermined wavelength value. A first source emitting first radiation is used to calibrate the spectrometer. A device is placed in the path of the first radiation to split the first radiation into a first beam and a second beam. The assembly is configured so that one of the first and second beams travels a path-difference distance longer than the other of the first and second beams. An output signal is generated by the spectrometer when the first and second beams enter the spectrometer. The assembly includes a controller operable for processing the output signal and adapted to calculate correction factors for the respective predetermined wavelength values assigned to each detector element.

Performances of a Compact, High-Power WB Source with Circular Polarization

NASA Astrophysics Data System (ADS)

Delmote, P.; Pinguet, S.; Bieth, F.

This paper presents the design and the performances of an embedded high-power microwave (HPM) wideband source, developed and built at the French-German Research Institute of Saint-Louis. The system was intended for dual use, homeland security, and military applications. It is powered by a 400 kV compact Marx generator with specificities in coaxial design and low energy. The slow monopolar signal from the Marx is sharpened using a pulse-forming stage, made of a switching module pressurized with nitrogen, followed by a monopulse-to-monocycle converter. The duration and rise times of this signal could be adjusted by varying the pressure and space between electrodes. Repetitive operations were performed up to 100 Hz during 10 s without a gas flow. Two kinds of antennas can be connected to the source. The first one is a TEM horn, with an optional dielectric lens, that radiates a vertically polarized UWB short pulse. The second one is a nine-turn helix, working in Kraus monopolar axial mode and radiating a circularly polarized wideband signal along the main axis. A dedicated conical reflector increases its directivity and bandwidth. The whole source is designed to be embedded inside an aluminum trailer, powered by batteries and remote controlled through an optical fiber.

Gadolinium-doped water cerenkov-based neutron and high energy gamma-ray detector and radiation portal monitoring system

DOEpatents

Dazeley, Steven A; Svoboda, Robert C; Bernstein, Adam; Bowden, Nathaniel

2013-02-12

A water Cerenkov-based neutron and high energy gamma ray detector and radiation portal monitoring system using water doped with a Gadolinium (Gd)-based compound as the Cerenkov radiator. An optically opaque enclosure is provided surrounding a detection chamber filled with the Cerenkov radiator, and photomultipliers are optically connected to the detect Cerenkov radiation generated by the Cerenkov radiator from incident high energy gamma rays or gamma rays induced by neutron capture on the Gd of incident neutrons from a fission source. The PMT signals are then used to determine time correlations indicative of neutron multiplicity events characteristic of a fission source.

Radiation exposure from work-related medical X-rays at the Portsmouth Naval Shipyard.

PubMed

Daniels, Robert D; Kubale, Travis L; Spitz, Henry B

2005-03-01

Previous analyses suggest that worker radiation dose may be significantly increased by routine occupational X-ray examinations. Medical exposures are investigated for 570 civilian workers employed at the Portsmouth Naval Shipyard (PNS) at Kittery, Maine. The research objective was to determine the radiation exposure contribution of work-related chest X-rays (WRX) relative to conventional workplace radiation sources. Methods were developed to estimate absorbed doses to the active (hematopoietic) bone marrow from X-ray examinations and workplace exposures using data extracted from worker dosimetry records (8,468) and health records (2,453). Dose distributions were examined for radiation and non-radiation workers. Photofluorographic chest examinations resulted in 82% of the dose from medical sources. Radiation workers received 26% of their collective dose from WRX and received 66% more WRX exposure than non-radiation workers. WRX can result in a significant fraction of the total dose, especially for radiation workers who were more likely to be subjected to routine medical monitoring. Omission of WRX from the total dose is a likely source of bias that can lead to dose category misclassification and may skew the epidemiologic dose-response assessment for cancers induced by the workplace.

Ultraviolet radiation induced discharge laser

DOEpatents

Gilson, Verle A.; Schriever, Richard L.; Shearer, James W.

1978-01-01

An ultraviolet radiation source associated with a suitable cathode-anode electrode structure, disposed in a gas-filled cavity of a high pressure pulsed laser, such as a transverse electric atmosphere (TEA) laser, to achieve free electron production in the gas by photoelectric interaction between ultraviolet radiation and the cathode prior to the gas-exciting cathode-to-anode electrical discharge, thereby providing volume ionization of the gas. The ultraviolet radiation is produced by a light source or by a spark discharge.

Precision disablement aiming system

DOEpatents

Monda, Mark J.; Hobart, Clinton G.; Gladwell, Thomas Scott

2016-02-16

A disrupter to a target may be precisely aimed by positioning a radiation source to direct radiation towards the target, and a detector is positioned to detect radiation that passes through the target. An aiming device is positioned between the radiation source and the target, wherein a mechanical feature of the aiming device is superimposed on the target in a captured radiographic image. The location of the aiming device in the radiographic image is used to aim a disrupter towards the target.

Tunable, superconducting, surface-emitting teraherz source

DOEpatents

Welp, Ulrich [Lisle, IL; Koshelev, Alexei E [Bolingbrook, IL; Gray, Kenneth E [Evanston, IL; Kwok, Wai-Kwong [Evanston, IL; Vlasko-Vlasov, Vitalii [Downers Grove, IL

2009-10-27

A compact, solid-state THz source based on the driven Josephson vortex lattice in a highly anisotropic superconductor such as Bi.sub.2Sr.sub.2CaCu.sub.2O.sub.8 that allows cw emission at tunable frequency. A second order metallic Bragg grating is used to achieve impedance matching and to induce surface emission of THz-radiation from a Bi.sub.2Sr.sub.2CaCu.sub.2O.sub.8 sample. Steering of the emitted THz beam is accomplished by tuning the Josephson vortex spacing around the grating period using a superimposed magnetic control field.

Tunable, superconducting, surface-emitting teraherz source

DOEpatents

Welp, Ulrich; Koshelev, Alexei E.; Gray, Kenneth E.; Kwok, Wai-Kwong; Vlasko-Vlasov, Vitalii

2010-05-11

A compact, solid-state THz source based on the driven Josephson vortex lattice in a highly anisotropic superconductor such as Bi.sub.2Sr.sub.2CaCu.sub.2O.sub.8 that allows cw emission at tunable frequency. A second order metallic Bragg grating is used to achieve impedance matching and to induce surface emission of THz-radiation from a Bi.sub.2Sr.sub.2CaCu.sub.2O.sub.8 sample. Steering of the emitted THz beam is accomplished by tuning the Josephson vortex spacing around the grating period using a superimposed magnetic control field.

Stratospheric aerosols and climatic change

NASA Technical Reports Server (NTRS)

Toon, O. B.; Pollack, J. B.

1978-01-01

Stratospht1ic sulfuric acid particles scatter and absorb sunlight and they scatter, absorb and emit terrestrial thermal radiation. These interactions play a role in the earth's radiation balance and therefore affect climate. The stratospheric aerosols are perturbed by volcanic injection of SO2 and ash, by aircraft injection of SO2, by rocket exhaust of Al2O3 and by tropospheric mixing of particles and pollutant SO2 and COS. In order to assess the effects of these perturbations on climate, the effects of the aerosols on the radiation balance must be understood and in order to understand the radiation effects the properties of the aerosols must be known. The discussion covers the aerosols' effect on the radiation balance. It is shown that the aerosol size distribution controls whether the aerosols will tend to warm or cool the earth's surface. Calculations of aerosol properties, including size distribution, for various perturbation sources are carried out on the basis of an aerosol model. Calculations are also presented of the climatic impact of perturbed aerosols due to volcanic eruptions and Space Shuttle flights.

Ionizing radiation test results for an automotive microcontroller on board the Schiaparelli Mars lander

NASA Astrophysics Data System (ADS)

Tapani Nikkanen, Timo; Hieta, Maria; Schmidt, Walter; Genzer, Maria; Haukka, Harri; Harri, Ari-Matti

2016-04-01

The Finnish Meteorological Institute (FMI) has delivered a pressure and a humidity instrument for the ESA ExoMars 2016 Schiaparelli lander mission. Schiaparelli is scheduled to launch towards Mars with the Trace Gas Orbiter on 14th of March 2016. The DREAMS-P (pressure) and DREAMS-H (Humidity) instruments are operated utilizing a novel FMI instrument controller design based on a commercial automotive microcontroller (MCU). A custom qualification program was implemented to qualify the MCU for the relevant launch, cruise and surface operations environment of a Mars lander. Resilience to ionizing radiation is one of the most critical requirements for a digital component operated in space or at planetary bodies. Thus, the expected Total Ionizing Dose accumulated by the MCU was determined and a sample of these components was exposed to a Co-60 gamma radiation source. Part of the samples was powered during the radiation exposure to include the effect of electrical biasing. All of the samples were verified to withstand the expected total ionizing dose with margin. The irradiated test samples were then radiated until failure to determine their ultimate TID.

Optical spectroscopy and microscopy of radiation-induced light-emitting point defects in lithium fluoride crystals and films

NASA Astrophysics Data System (ADS)

Montereali, R. M.; Bonfigli, F.; Menchini, F.; Vincenti, M. A.

2012-08-01

Broad-band light-emitting radiation-induced F2 and F3+ electronic point defects, which are stable and laser-active at room temperature in lithium fluoride crystals and films, are used in dosimeters, tuneable color-center lasers, broad-band miniaturized light sources and novel radiation imaging detectors. A brief review of their photoemission properties is presented, and their behavior at liquid nitrogen temperatures is discussed. Some experimental data from optical spectroscopy and fluorescence microscopy of these radiation-induced point defects in LiF crystals and thin films are used to obtain information about the coloration curves, the efficiency of point defect formation, the effects of photo-bleaching processes, etc. Control of the local formation, stabilization, and transformation of radiation-induced light-emitting defect centers is crucial for the development of optically active micro-components and nanostructures. Some of the advantages of low temperature measurements for novel confocal laser scanning fluorescence microscopy techniques, widely used for spatial mapping of these point defects through the optical reading of their visible photoluminescence, are highlighted.

Development of Partially-Coherent Wavefront Propagation Simulation Methods for 3rd and 4th Generation Synchrotron Radiation Sources.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chubar O.; Berman, L; Chu, Y.S.

2012-04-04

Partially-coherent wavefront propagation calculations have proven to be feasible and very beneficial in the design of beamlines for 3rd and 4th generation Synchrotron Radiation (SR) sources. These types of calculations use the framework of classical electrodynamics for the description, on the same accuracy level, of the emission by relativistic electrons moving in magnetic fields of accelerators, and the propagation of the emitted radiation wavefronts through beamline optical elements. This enables accurate prediction of performance characteristics for beamlines exploiting high SR brightness and/or high spectral flux. Detailed analysis of radiation degree of coherence, offered by the partially-coherent wavefront propagation method, ismore » of paramount importance for modern storage-ring based SR sources, which, thanks to extremely small sub-nanometer-level electron beam emittances, produce substantial portions of coherent flux in X-ray spectral range. We describe the general approach to partially-coherent SR wavefront propagation simulations and present examples of such simulations performed using 'Synchrotron Radiation Workshop' (SRW) code for the parameters of hard X-ray undulator based beamlines at the National Synchrotron Light Source II (NSLS-II), Brookhaven National Laboratory. These examples illustrate general characteristics of partially-coherent undulator radiation beams in low-emittance SR sources, and demonstrate advantages of applying high-accuracy physical-optics simulations to the optimization and performance prediction of X-ray optical beamlines in these new sources.« less

Method for sequencing DNA base pairs

DOEpatents

Sessler, Andrew M.; Dawson, John

1993-01-01

The base pairs of a DNA structure are sequenced with the use of a scanning tunneling microscope (STM). The DNA structure is scanned by the STM probe tip, and, as it is being scanned, the DNA structure is separately subjected to a sequence of infrared radiation from four different sources, each source being selected to preferentially excite one of the four different bases in the DNA structure. Each particular base being scanned is subjected to such sequence of infrared radiation from the four different sources as that particular base is being scanned. The DNA structure as a whole is separately imaged for each subjection thereof to radiation from one only of each source.

Electromagnetic energy and food processing.

PubMed

Mudgett, R

1988-01-01

The use of electromagnetic energy in food processing is reviewed with respect to food safety, nutritional quality, and organoleptic quality. The effects of nonionizing radiation sources such as microwave and radio-frequency energy and ionizing radiation sources, e.g. radioactive cobalt-60 and caesium-137, on the inactivation of microbes and nutrients are compared with those of conventional heating processes both in terms of their kinetic behavior and their mechanisms of interaction with foods. The kinetics of microwave and conventional thermal inactivation are considered for a generalized nth-order model based on time and temperature conditions. However, thermal inactivation effects are often modeled by 1st-order kinetics. Microbial and nutrient inactivation by ionizing sources are considered for a 1st-order model based on radiation dose. Both thermal and radiation resistance concepts are reviewed and some typical values of radiation resistance are given for sensitive vegetative bacterial cells, yeasts, and molds and for resistant bacterial spores and viruses. Nonionizing microwave energy sources are increasingly used in home and industrial food processing and are well-accepted by the American public. But, despite recent Food and Drug Administration approval of low and intermediate ionizing radiation dose levels for grains and other plants products and the fact that irradiated foods are sold in more than 20 countries of the world, public fears in the U.S. about nuclear energy may limit the role of ionizing radiation in food processing and preservation and may also limit the use of nuclear fuels as an alternate source of electrical energy.

An experimental investigation of sound radiation from a duct with a circumferentially varying liner

NASA Technical Reports Server (NTRS)

Fuller, C. R.; Silcox, R. J.

1983-01-01

The radiation of sound from an asymmetrically lined duct is experimentally studied for various hard-walled standing mode sources. Measurements were made of the directivity of the radiated field and amplitude reflection coefficients in the hard-walled source section. These measurements are compared with baseline hardwall and uniformly lined duct data. The dependence of these characteristics on mode number and angular location of the source is investigated. A comparison between previous theoretical calculations and the experimentally measured results is made and in general good agreement is obtained. For the several cases presented an asymmetry in the liner impedance distribution was found to produce related asymmetries in the radiated acoustic field.

Electronic Subsystem Analysis (ESA)

DTIC Science & Technology

1977-01-01

than aluminum for the gate material, 0 Ion implanted source and draia regions, 0 Dielectrically isolated transistors. The use of a doped polysilicon gate...second level of interconnect ( polysilicon ). Ion implantation is essentially a precisely controllable pre-deposition of the required dopants. It’s use...discussed below). Radiation effects on MOS devices include the following: 0 Total Dose ol Dose Rate o Neutrons Because MOS technology is based on

10 CFR 35.590 - Training for use of sealed sources for diagnosis.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Training for use of sealed sources for diagnosis. 35.590 Section 35.590 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Sealed Sources for...— (1) Radiation physics and instrumentation; (2) Radiation protection; (3) Mathematics pertaining to...

10 CFR 35.590 - Training for use of sealed sources for diagnosis.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Training for use of sealed sources for diagnosis. 35.590 Section 35.590 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Sealed Sources for...— (1) Radiation physics and instrumentation; (2) Radiation protection; (3) Mathematics pertaining to...

10 CFR 35.590 - Training for use of sealed sources for diagnosis.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Training for use of sealed sources for diagnosis. 35.590 Section 35.590 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Sealed Sources for...— (1) Radiation physics and instrumentation; (2) Radiation protection; (3) Mathematics pertaining to...

10 CFR 35.590 - Training for use of sealed sources for diagnosis.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Training for use of sealed sources for diagnosis. 35.590 Section 35.590 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Sealed Sources for...— (1) Radiation physics and instrumentation; (2) Radiation protection; (3) Mathematics pertaining to...

The direct collapse of a massive black hole seed under the influence of an anisotropic Lyman-Werner source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Regan, John A.; Johansson, Peter H.; Wise, John H., E-mail: john.regan@helsinki.fi

2014-11-10

The direct collapse model of supermassive black hole seed formation requires that the gas cools predominantly via atomic hydrogen. To this end we simulate the effect of an anisotropic radiation source on the collapse of a halo at high redshift. The radiation source is placed at a distance of 3 kpc (physical) from the collapsing object and is set to emit monochromatically in the center of the Lyman-Werner (LW) band. The LW radiation emitted from the high redshift source is followed self-consistently using ray tracing techniques. Due to self-shielding, a small amount of H{sub 2} is able to form atmore » the very center of the collapsing halo even under very strong LW radiation. Furthermore, we find that a radiation source, emitting >10{sup 54} (∼ 10{sup 3} J{sub 21}) photons s{sup –1}, is required to cause the collapse of a clump of M ∼ 10{sup 5} M {sub ☉}. The resulting accretion rate onto the collapsing object is ∼0.25 M {sub ☉} yr{sup –1}. Our results display significant differences, compared to the isotropic radiation field case, in terms of the H{sub 2} fraction at an equivalent radius. These differences will significantly affect the dynamics of the collapse. With the inclusion of a strong anisotropic radiation source, the final mass of the collapsing object is found to be M ∼ 10{sup 5} M {sub ☉}. This is consistent with predictions for the formation of a supermassive star or quasi-star leading to a supermassive black hole.« less

Coherence properties of blackbody radiation and application to energy harvesting and imaging with nanoscale rectennas

NASA Astrophysics Data System (ADS)

Lerner, Peter B.; Cutler, Paul H.; Miskovsky, Nicholas M.

2015-01-01

Modern technology allows the fabrication of antennas with a characteristic size comparable to the electromagnetic wavelength in the optical region. This has led to the development of new technologies using nanoscale rectifying antennas (rectennas) for solar energy conversion and sensing of terahertz, infrared, and visible radiation. For example, a rectenna array can collect incident radiation from an emitting source and the resulting conversion efficiency and operating characteristics of the device will depend on the spatial and temporal coherence properties of the absorbed radiation. For solar radiation, the intercepted radiation by a micro- or nanoscale array of devices has a relatively narrow spatial and angular distribution. Using the Van Cittert-Zernike theorem, we show that the coherence length (or radius) of solar radiation on an antenna array is, or can be, tens of times larger than the characteristic wavelength of the solar spectrum, i.e., the thermal wavelength, λT=2πℏc/(kBT), which for T=5000 K is about 3 μm. Such an effect is advantageous, making possible the rectification of solar radiation with nanoscale rectenna arrays, whose size is commensurate with the coherence length. Furthermore, we examine the blackbody radiation emitted from an array of antennas at temperature T, which can be quasicoherent and lead to a modified self-image, analogous to the Talbot-Lau self-imaging process but with thermal rather than monochromatic radiation. The self-emitted thermal radiation may be important as a nondestructive means for quality control of the array.

Coupling control and optimization at the Canadian Light Source

NASA Astrophysics Data System (ADS)

Wurtz, W. A.

2018-06-01

We present a detailed study using the skew quadrupoles in the Canadian Light Source storage ring lattice to control the parameters of a coupled lattice. We calculate the six-dimensional beam envelop matrix and use it to produce a variety of objective functions for optimization using the Multi-Objective Particle Swarm Optimization (MOPSO) algorithm. MOPSO produces a number of skew quadrupole configurations that we apply to the storage ring. We use the X-ray synchrotron radiation diagnostic beamline to image the beam and we make measurements of the vertical dispersion and beam lifetime. We observe satisfactory agreement between the measurements and simulations. These methods can be used to adjust phase space coupling in a rational way and have applications to fine-tuning the vertical emittance and Touschek lifetime and measuring the gas scattering lifetime.

Active electromagnetic invisibility cloaking and radiation force cancellation

NASA Astrophysics Data System (ADS)

Mitri, F. G.

2018-03-01

This investigation shows that an active emitting electromagnetic (EM) Dirichlet source (i.e., with axial polarization of the electric field) in a homogeneous non-dissipative/non-absorptive medium placed near a perfectly conducting boundary can render total invisibility (i.e. zero extinction cross-section or efficiency) in addition to a radiation force cancellation on its surface. Based upon the Poynting theorem, the mathematical expression for the extinction, radiation and amplification cross-sections (or efficiencies) are derived using the partial-wave series expansion method in cylindrical coordinates. Moreover, the analysis is extended to compute the self-induced EM radiation force on the active source, resulting from the waves reflected by the boundary. The numerical results predict the generation of a zero extinction efficiency, achieving total invisibility, in addition to a radiation force cancellation which depend on the source size, the distance from the boundary and the associated EM mode order of the active source. Furthermore, an attractive EM pushing force on the active source directed toward the boundary or a repulsive pulling one pointing away from it can arise accordingly. The numerical predictions and computational results find potential applications in the design and development of EM cloaking devices, invisibility and stealth technologies.

Radiation and People

ERIC Educational Resources Information Center

Freilich, Florence G.

1970-01-01

Describes the development of radiation as a tool of medicine. Includes topics on history of radiation, electromagnetic spectrum, X-ray tubes, high energy machines, radioactive sources, artificial radioactivity, radioactive scanning, units, present radiation background, and effect of radiation on living tissue. (DS)

Measurement and Analysis of the Noise Radiated by Low Mach Number Centrifugal Blowers.

NASA Astrophysics Data System (ADS)

Yeager, David Marvin

An investigation was performed of the broad band, aerodynamically generated noise in low tip-speed Mach number, centrifugal air moving devices. An interdisciplinary experimental approach was taken which involved investigation of the aerodynamic and acoustic fields, and their mutual relationship. The noise generation process was studied using two experimental vehicles: (1) a scale model of a homologous family of centrifugal blowers typical of those used to cool computer and business equipment, and (2) a single blade from a centrifugal blower impeller placed in a known, controllable flow field. The radiation characteristics of the model blower were investigated by measuring the acoustic intensity distribution near the blower inlet and comparing it with the intensity near the inlet to an axial flow fan. Results showed that the centrifugal blower is a distributed, random noise source, unlike an axial fan which exhibited the effects of a coherent, interacting source distribution. Aerodynamic studies of the flow field in the inlet and at the discharge to the rotating impeller were used to assess the mean flow distribution through the impeller blade channels and to identify regions of excessive turbulence near the rotating blade row. Both circumferential and spanwise mean flow nonuniformities were identified along with a region of increased turbulence just downstream of the scroll cutoff. The fluid incidence angle, normally taken as an indicator of blower performance, was estimated from mean flow data as deviating considerably from an ideal impeller design. An investigation of the noise radiated from the single, isolated airfoil was performed using modern correlation and spectral analysis techniques. Radiation from the single blade in flow was characterized using newly developed expressions for the correlation area and the dipole source strength per unit area, and from the relationship between the blade surface pressure and the incident turbulent flow field. Results showed that radiation from the single blade was dominated by the effects of the incident turbulence. Normalized correlations areas of approximately 25% were measured at low frequencies. While the noise generation was more efficient at the trailing edge of the isolated blade, more noise was radiated from the region near the leading edge.

Compound simulator IR radiation characteristics test and calibration

NASA Astrophysics Data System (ADS)

Li, Yanhong; Zhang, Li; Li, Fan; Tian, Yi; Yang, Yang; Li, Zhuo; Shi, Rui

2015-10-01

The Hardware-in-the-loop simulation can establish the target/interference physical radiation and interception of product flight process in the testing room. In particular, the simulation of environment is more difficult for high radiation energy and complicated interference model. Here the development in IR scene generation produced by a fiber array imaging transducer with circumferential lamp spot sources is introduced. The IR simulation capability includes effective simulation of aircraft signatures and point-source IR countermeasures. Two point-sources as interference can move in two-dimension random directions. For simulation the process of interference release, the radiation and motion characteristic is tested. Through the zero calibration for optical axis of simulator, the radiation can be well projected to the product detector. The test and calibration results show the new type compound simulator can be used in the hardware-in-the-loop simulation trial.

Sound source identification and sound radiation modeling in a moving medium using the time-domain equivalent source method.

PubMed

Zhang, Xiao-Zheng; Bi, Chuan-Xing; Zhang, Yong-Bin; Xu, Liang

2015-05-01

Planar near-field acoustic holography has been successfully extended to reconstruct the sound field in a moving medium, however, the reconstructed field still contains the convection effect that might lead to the wrong identification of sound sources. In order to accurately identify sound sources in a moving medium, a time-domain equivalent source method is developed. In the method, the real source is replaced by a series of time-domain equivalent sources whose strengths are solved iteratively by utilizing the measured pressure and the known convective time-domain Green's function, and time averaging is used to reduce the instability in the iterative solving process. Since these solved equivalent source strengths are independent of the convection effect, they can be used not only to identify sound sources but also to model sound radiations in both moving and static media. Numerical simulations are performed to investigate the influence of noise on the solved equivalent source strengths and the effect of time averaging on reducing the instability, and to demonstrate the advantages of the proposed method on the source identification and sound radiation modeling.

Real-time self-networking radiation detector apparatus

DOEpatents

Kaplan, Edward [Stony Brook, NY; Lemley, James [Miller Place, NY; Tsang, Thomas Y [Holbrook, NY; Milian, Laurence W [East Patchogue, NY

2007-06-12

The present invention is for a radiation detector apparatus for detecting radiation sources present in cargo shipments. The invention includes the features of integrating a bubble detector sensitive to neutrons and a GPS system into a miniaturized package that can wirelessly signal the presence of radioactive material in shipping containers. The bubble density would be read out if such indicated a harmful source.

Sound Radiated by a Wave-Like Structure in a Compressible Jet

NASA Technical Reports Server (NTRS)

Golubev, V. V.; Prieto, A. F.; Mankbadi, R. R.; Dahl, M. D.; Hixon, R.

2003-01-01

This paper extends the analysis of acoustic radiation from the source model representing spatially-growing instability waves in a round jet at high speeds. Compared to previous work, a modified approach to the sound source modeling is examined that employs a set of solutions to linearized Euler equations. The sound radiation is then calculated using an integral surface method.

Observations of Galactic gamma-radiation with the SMM spectrometer

NASA Technical Reports Server (NTRS)

Share, G. H.; Kinzer, R. L.; Messina, D. C.; Purcell, W. R.; Chupp, E. L.

1986-01-01

Preliminary results from the SMM gamma-ray spectrometer are reported which indicate the detection of a constant source of 0.511-MeV annihilation radiation from the Galaxy. Year-to-year variability appears to be less than 30 percent. The radiation probably comes from a diffuse source and is not associated with the reported compact object at the Galactic center.