Health Physics Research Articles

Response to Letters from Andrews and Tans, Edwards, and Musolino commenting on Skrable et al.-"World Atmospheric CO2, Its 14C Specific Activity, Non-fossil Component, Anthropogenic Fossil Component, and Emissions (1750-2018)".

Health Physics Editor-In-Chief [email protected] (513) 805–3445 The author declares no conflicts of interest.

Comments on "World Atmospheric CO2, Its 14C Specific Activity, Non-fossil Component, Anthropogenic Fossil Component, and Emissions" by Skrable et al. (2022).

Associate Editor, Health Physics, Brookhaven National Laboratory, Nonproliferation and National Security Department, P.O. Box 5000, Upton, New York, 11973-5000[email protected] The authors declare no conflicts of interest. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

Peter A. Darnell (1962-2021).

Health Physics: June 2022 - Volume 122 - Issue 6 - p 705-706 doi: 10.1097/HP.0000000000001549

The Effect of Grain Size on Porewater Radiolysis

AbstractThe radiolysis of porewaters by uranium, thorium, and potassium in mineral grains is a recognized source of molecular hydrogen in rock‐hosted and sediment‐hosted fluids. This radiolytic hydrogen is of geomicrobiological interest as a potential energy source (electron donor) for microbial metabolism, especially in energy‐limited settings such as the marine deep biosphere or the subsurface of Mars. Previous efforts to predict the production of radiolytic hydrogen from columns of rock and sediment have tended to rely upon analytic models that cannot account for the attenuation of mineral radiation by grains larger than ∼30 µm. To address this, we have developed a Monte Carlo method to simulate the physics of mineral radiation and evaluate the production of H2 as a function of mineral grain size and radioisotope composition. The results confirm that grain size is a major control on radiolytic H2 yield. For example, using the standard geological classification of grain sizes, we find that clay can produce up to an order of magnitude more H2 per unit time than sand. The magnitude of this effect is illustrated using compositional data from real geological units in order to demonstrate the dependence of radiolytic hydrogen flux on natural radionuclide concentration and bulk porosity.

Hybrid analytical method for calibrating a standard NaI(Tl) gamma-ray scintillation detector using a lateral hexagonal radioactive source

In various fields of radiation and nuclear physics, research and its applications help in the management and control of human activities, especially in the analysis of nuclear waste and measurement of low activity environmental samples. The current study uses a hybrid analytical technique and a 152Eu lateral hexagonal radioactive source to calibrate a standard cylindrical NaI(Tl) γ-ray scintillation detector. The technique is a combination of experimental measurements and theoretical calculations because for each environmental and/or radioactive waste sample, a separate reference calibration source equivalent to samples of different compositions is required, which needs additional funding. This method is suitable for any source–detector geometry. It can be used to calculate the geometric, total, and full-energy peak efficiency and the P/T ratio using the model probability of detecting γ-radiation photons, in particular from a lateral hexagonal radioactive source. The detection probability can be mainly influenced by the direction of the γ-quantum motion. This can help build more realistic and complex models than the typical point source case, where simple integration is used to numerically calculate the efficiency of the detection system. Using this method, the self-attenuation and coincidence-summing effect can be calculated for any gamma source matrices. The results obtained can show how useful this technique can be for calibrating complex gamma-ray detectors with any type of gamma-ray source.

A Radiological Emergency Health and Safety Plan for City Agencies Without First Response Responsibilities.

In New York City, the citywide radiological response plan charges 4 primary agencies with various roles and objectives: police, fire, health, and environmental protection. These agencies perform essential functions such as criminal investigation, life safety, public health, and environmental assessments. In the late phase of an incident where components of remediation and recovery have been initiated, other municipal agencies that had not previously planned to respond to a radiological incident may be expected to supply various levels of support. To prepare the personnel of these other agencies to respond to a radiological incident expeditiously, a Radiological Health and Safety Plan (RHASP), was developed as an appendix to an existing Citywide Health and Safety Plan. RHASP is designed for an agency-wide health physics program that provides 4 key components of radiation safety: (1) training to understand the hazard, (2) framework for a personnel radiation dose measurement program (dosimetry), (3) environmental surveillance of the site for worker and public protection, and (4) radioactive waste control. These components of RHASP are supported by 2 functions inherent in successful radiation safety programs: documentation and quality assurance of the collected radiation safety data. In this article, we discuss the components of RHASP and the potential challenges to its successful implementation.

British nuclear test veteran family trios for the study of genetic risk

The risk of radiation effects in children of individuals exposed to ionising radiation remains an ongoing concern for aged veterans of the British nuclear testing programme. The genetic and cytogenetic family trio (GCFT) study is the first study to obtain blood samples from a group of British nuclear test veterans and their families for the purposes of identifying genetic alterations in offspring as a consequence of historical paternal exposure to ionising radiation. In this report, we describe the processes for recruitment and sampling, and provide a general description of the study population recruited. In total, blood samples were received from 91 (49 test and 42 control) families representing veteran servicemen from the army, Royal Air Force and Royal Navy. This translated to an overall response rate of 14% (49/353) for test veterans and 4% (42/992) for control veterans (excluding responders known to be ineligible). Due to the lack of dose information available, test veterans were allocated to a three-point exposure rank. Thirty (61%) test veterans were ranked in the lower group. Nineteen (39%) of the 49 test veterans were classified in the mid (5 veterans; 10%)/high (14 veterans; 29%) exposure ranks and included 12 veterans previously identified as belonging to the special groups or listed in health physics documents. An increased number of test veteran families (20%), compared with control families (5%), self-reported offspring with congenital abnormalities (p = 0.03). Whether this observation in this small group is reflective of the entire UK test veteran cohort or whether it is selection bias requires further work. The cohort described here represent an important and unique family trio grouping whose participation is enabling genetic studies, as part of the GCFT study, to be carried out. The outcomes of these studies will be published elsewhere. ISRCTN Registry: 17461668.

Health Physics Society Affiliate Members

Health Physics: June 2022 - Volume 122 - Issue 6 - p 738 doi: 10.1097/01.HP.0000831024.74404.b8

RadStat: An open-source statistical analysis tool for counts obtained by a GM counter.

The interaction of ionizing radiation with matter is a stochastic process and statistical analysis of such a process would be a crucial step in understanding radioactivity. Geiger–Müller (GM) counter is a widely used radiation detector used in nuclear radiation surveying, which produces counts upon exposure to a radioactive source. There are a variety of multi-purpose software that can be used to perform statistical analysis of measured counts from a GM counter. However, statistical analysis is a lengthy, error prone and time-consuming process, which gets more tedious when the number of measurements increases. In the present work, we have developed an open-source and easy-to-use graphical user interface (GUI) computer program named RadStat for statistical analysis of counts measured by a GM counter. RadStat has its own scripting syntaxes and bundled with gnuplot for quick visualization of output results. We believe the present open-source GUI program would be a useful tool for research and teaching of nuclear radiation physics.

Health Physics (보건 물리학) in South Korea: Building a Research Community in a Post-Colonial Society, 1959–early 1970s

This paper traces the diverse contexts of radiation protection from liberation in post-1945 South Korea to its professionalization by the early 1970s, using the emerging field of health physics (보건 물리학) as the focus. The Korean nuclear center, AERI (Atomic Energy Research Institute/한국 원자력 연구소, 1959), started two affiliates, RRIA (Radiation Research Institute for Agriculture/방사선 농업연구소, 1966) and RRIM (Radiation Research Institute for Medicine/방사선 의학연구소, 1963) in the early 1960s. In particular, RRIM emphasized the use of radiation within cancer research, especially the use of cobalt in treating patients. In this context, health physics initially took the form of “radiation medicine.”With the two institutes returning to AERI’s fold in 1973, health physics took another turn: the second major subfield, following “radiation medicine,” invoked a broader conception of “radiation protection,” which now referred to a cluster of related interests, including the environment and the effects of industrialization.Rather than a simple transfer of American and international models after 1953, Korean health physics reflects its origins in a post-colonial research setting, one more diverse than its “official” institutional context at AERI.

Improving the cloud initialization in WRF-Solar with enhanced short-range forecasting functionality: The MAD-WRF model

In spite of WRF-Solar being a numerical weather prediction (NWP) model specifically tailored for solar energy applications, the model lacks a specific cloud initialization component to improve short-range predictions. To overcome this limitation we have combined the fundamental concepts of the Multi-sensor Advection Diffusion nowCast (MADCast) model of using satellite observations to detect the clouds and advect and diffuse the clouds within a NWP model, with the better cloud–aerosol–radiation physics of WRF-Solar, into a new model referred to as MAD-WRF. The MAD-WRF cloud initialization combines a cloud parameterization that infers the presence of clouds based on relative humidity with observations of the cloud mask and cloud top/base height to provide a three-dimensional cloud analysis (liquid, ice, and snow hydrometeor content). During the forecasts, the hydrometeors can be advected and diffused with no microphysics, in what we refer to as the MAD-WRF passive mode. Alternatively, these passive hydrometeors can be integrated into the explicitly resolved hydrometeors during a nudging phase, designated the MAD-WRF active mode. In the nudging phase, there is a relaxation of the resolved hydrometeors towards the passive hydrometeors. Both modes aim to avoid an abrupt dissipation of clouds if the atmospheric environment is not adequate to support them. Both MAD-WRF active and passive modes as well as WRF-Solar have been run in a demonstration of MAD-WRF over the contiguous U.S., and results from these short-range forecasts (0–6 h) are presented here to illustrate the added value of MAD-WRF for global horizontal irradiance predictions. These results clearly illustrate the added value that MAD-WRF brings for short term irradiance predictions with the WRF-Solar model.

Advances in Radiation Oncology: Current Status and Future Directions in India.

Radiation therapy is one of the core components of the comprehensive cancer care. Several new advancements in the radiation physics, radiation biology, and technical upgradation have led us in to a new era of radiation oncology. The access to quality radiation therapy treatment however remains a concern, and this mini-review emphasizes on these issues and also focuses on the future directions for radiation oncology in India.

Laboratory experiments on the radiation astrochemistry of water ice phases

Water (H2O) ice is a ubiquitous component of the universe, having been detected in a variety of interstellar and Solar System environments where radiation plays an important role in its physico-chemical transformations. Although the radiation chemistry of H2O astrophysical ice analogues has been well studied, direct and systematic comparisons of different solid phases are scarce and are typically limited to just two phases. In this article, we describe the results of an in-depth study of the 2 keV electron irradiation of amorphous solid water (ASW), restrained amorphous ice (RAI) and the cubic (Ic) and hexagonal (Ih) crystalline phases at 20 K so as to further uncover any potential dependence of the radiation physics and chemistry on the solid phase of the ice. Mid-infrared spectroscopic analysis of the four investigated H2O ice phases revealed that electron irradiation of the RAI, Ic, and Ih phases resulted in their amorphization (with the latter undergoing the process more slowly) while ASW underwent compaction. The abundance of hydrogen peroxide (H2O2) produced as a result of the irradiation was also found to vary between phases, with yields being highest in irradiated ASW. This observation is the cumulative result of several factors including the increased porosity and quantity of lattice defects in ASW, as well as its less extensive hydrogen-bonding network. Our results have astrophysical implications, particularly with regards to H2O-rich icy interstellar and Solar System bodies exposed to both radiation fields and temperature gradients.Graphical abstract

Health Physics Society Affiliate Members

Health Physics Society Affiliate Members

222Rn Activity Concentration Measurement and its Radiological Risks in the Environment of Barserin Village, Erbil-Iraq

222Rn Activity Concentration Measurement and its Radiological Risks in the Environment of Barserin Village, Erbil-Iraq

Atmospheric dispersion modeling for an accidental release from a SLOWPOKE-2 research reactor: a case study.

Atmospheric dispersion modeling was performed for a postulated design basis accident at a SLOWPOKE research reactor. The MCNP-5 computer code was used to estimate the neutron flux spectrum which was then used in the ORIGEN-S code to perform core depletion calculations and determine the radiological source term. The HotSpot health physics code was then used to model the atmospheric transport of the radioactive material released to estimate the resulting doses to the population downwind of the reactor. The highest total effective dose (TED) for a release from the reactor's exhaust stack in predominant meteorological conditions, stability class C, was 0.37mSv, while a maximum TED of 4.29mSv was estimated for a release at ground level. Ground deposition was estimated to be 3900kBq/m2. It was shown that any hypothetical release of radioactive material resulting from such an accident would have no significant adverse effect on the municipal water reservoir close to the reactor.

Thick shielding against galactic cosmic radiation: A Monte Carlo study with focus on the role of secondary neutrons

The exposure to galactic cosmic radiation (GCR) is a major health concern for astronauts. Crewed missions with durations of several years are foreseen in future space exploration projects such as permanent habitats on the Moon and flights to Mars. This aim requires elaborate space radiation shielding concepts and a proper understanding of the underlying radiation physics and radiobiology as well as their interplay.In the present work, Monte Carlo simulations to assess the performance of different materials (polyethylene, aluminum, Moon regolith) as thick shields (up to 400 g/cm2) against GCR were conducted using the FLUKA code. Absorbed dose, dose equivalent and the mean quality factor at 1 cm depth in the ICRU sphere as a function of shielding thickness were calculated in a spherical shell configuration for both solar minimum and solar maximum GCR conditions. Large differences were observed in the performance of the studied materials as thick GCR shields. Special attention was paid to the build-up and moderation of secondary neutrons. A method to reduce the neutron contributions to ambient dose equivalent by means of a two-layer shielding combination is proposed. The present study can be useful for considerations on thick shielding of Moon or Mars habitats built from local regolith.

Characterization of MOSFET Dosimeters for Alpha Particle Therapy

Alpha particle therapy, such as diffusing alpha-emitters radiation therapy (DaRT) and targeted alpha-particle therapy (TAT), exploits the short range and high linear energy transfer (LET) of alpha particles to destroy cancer cells locally with minimal damage to surrounding healthy cells. Dosimetry for DaRT and TAT is challenging, as their radiation sources produce mixed radiation fields of <inline-formula> <tex-math notation="LaTeX">$\alpha $ </tex-math></inline-formula> particles, <inline-formula> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> particles, and <inline-formula> <tex-math notation="LaTeX">$\gamma $ </tex-math></inline-formula> rays. There is currently no dosimeter for real-time <b><i>in vivo</i></b> dosimetry of DaRT or TAT. Metal-oxide-semiconductor field-effect transistors (MOSFETs) have features that are ideal for this scenario. They can be read out in real-time nondestructively, store information permanently, and their sensitivity to radiation can be varied by changing the bias on the gate during irradiation. Moreover, owing to their compactness, MOSFETs can fit into fine-gauge needle applicators, such as those used to carry radioactive seeds into the tumor. This study characterized the response of MOSFETs designed at the Centre for Medical and Radiation Physics, University of Wollongong. Irradiations were performed with a mono-energetic helium ion beam (He^2&#x002B;) of 5.5 MeV and an Americium-241 (²⁴¹Am) source, for MOSFETs with three different gate oxide thicknesses (0.55, 0.68, and 1.0 <inline-formula> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula>). The results showed that the response was linear with alpha dose up to 25 Gy. Also, it was found that a gate bias of between 15 and 60 V would optimize the sensitivity to alpha particles with energy of 5.5 MeV.

Comparison of rocket launch data to empirical models for overall level and peak directivity angle

With increasing frequency in global rocket launches, it is important to assess the effects of liftoff noise. Understanding of the fundamental physics of the sound radiation from rocket exhaust plumes remains limited. Some empirical predictive models, derived from plume parameters, cover aspects of the sound radiation, such as convective Mach number, peak directivity angle, and overall sound pressure level in the direction of maximum emission. These are evaluated using high-fidelity noise data from a number of different launches from Vandenberg Space Force Base. Initial results of the model comparisons will be presented.

Health Physics Society Abstracts: 2021 Mid-year Workshop and 66th Annual Meeting.

Health Physics Society Abstracts: 2021 Mid-year Workshop and 66th Annual Meeting.