Photon Dose Rate Research Articles

Investigation of the level of DNA double-strand breaks and mechanisms of cell death under irradiation of lung cancer and melanoma cells with ultra-high dose rate photon radiation

Research into the effects of radiation delivered at ultrahigh dose rates > 1 × 107 Gy/min to biological objects is a new promising area of radiobiology. The unique characteristics of the high-current nanosecond electron accelerator Mir-M enable its use in medical and biological research, specifically in the experiments aimed at investigating the effect of therapeutic doses at a dose rate up to 100 MGy/s. In this work we study the effects of ultrahigh dose rate photon radiation on human lung carcinoma (A549) and melanoma (MelMtp-x) cells lines and compare them with those of the therapeutic gamma unit Rokus-AM. We show that ultrahigh dose rates induce more significant damage in the studied cell lines at doses between 2 and 7 Gy, radioresistant melanoma being more sensitive to photon radiation delivered at ultrahigh dose rates.

Calculation of photon attenuation coefficient and dose rate in concrete with the addition of SiO2 and MnFe2O4 nanoparticles using MCNPX code and comparison with experimental results

One of the most important safety features of nuclear facilities is the shielding material used to protect the operating personnel from radiation exposure. The most common materials used in radiation shielding are concretes. In this study, a Monte Carlo N-Particle eXtended code is used to calculate the gamma-ray attenuation coefficients and dose rates for a new concrete material composed of MnFe2O4 nanoparticles, which is then compared with the theoretical and experimental results obtained for a SiO2 nanoparticle concrete material. According to the results, the average relative differences between the simulations and the theoretical and experimental results for the linear attenuation coefficient (μ) in the SiO2 nanoparticle materials are 6.4% and 5.5%, respectively. By increasing the SiO2 content up to 1.5% and the temperature of MnFe2O4 up to 673 K, μ is increased for all energies. In addition, the photon dose rate decreases up to 9.2% and 3.7% for MnFe2O4 and SiO2 for gamma-ray energies of 0.511 and 1.274 MeV, respectively. Therefore, it was concluded that the addition of SiO2 and MnFe2O4 nanoparticles to concrete improves its nuclear properties and could lead to it being more useful in radiation shielding.

OA203] Assessment of radiation exposure in a newly formed nuclear medicine department

Purpose In an oncology nuclear medicine department, radioisotopes are not only used for tumor detecting, staging, evaluation of therapy response but also for therapeutic purposes. This study documents the radiation exposure of departmental staff, related to cyclotron operation and service during the production and injection of 18F radiopharmaceuticals for PET/CT examination. In addition, it investigates exposure in a multiple holding tank system used for the storage of 131I waste generated from patients undergoing thyroid therapy, in order to optimize environmental protection procedures. Methods Measurements for the dose rates of neutrons and photons in the room of ABT-BG-75 self-shielded mini-cyclotron were recorded during bombardment for 18F-FDG production using a neutron detector and a scintillation dosimeter. The correlation between the duration of bombardment and required time to reach a dose rate equal to background level was investigated. An electronic dosimeter was used to record staff exposure for 18F production, dispensing, administration and imaging using PET-CT. Finally, the decay rate of 131I waste was measured using a dose rate meter positioned in the decay tank system of the radioactive iodine isolation ward. Results The time required for the cyclotron room to reach background level following completion of bombardment (3 × 50 min each) was approximately 2 h. The dose rate from neutrons was found to be negligible and from photons was less than 7.5 μ Sv/h. Therefore, personnel can safely enter the room during bombardment. The staff mean whole-body dose per 18F-administered patient was 1–2 μ Sv, depending on patient condition. The values obtained from the 131I radioactive waste stored in a delay tank system were comparable with theoretical values. Conclusion This study is useful for optimizing radiation exposure in an oncology nuclear medicine department. It is shown that during 18F production exposure is mostly attributed to photons. The level of the dose permits staff entry into the cyclotron room. Staff responsible for administration received 1–2 μ Sv per 18F-patient, considered to be on the lower end of the acceptable limit for a radiation worker. The study also documents the decay rate of 131I waste over the period which the suggested activity level for release in the environment is reached.

Characterisation of two new radiochromic gel dosimeters TruView™ and ClearView™ in combination with the vista™ optical CT scanner: A feasibility study

PurposeThis study aims at characterising the properties of TruView™ and ClearView™ two new gel dosimeters (Modus Medical Devices Inc.) and at studying the feasibility of relative dosimetry using these dosimeters and the Vista™ Optical CT scanner to accurately evaluate dose. MethodsIn this work, we investigated key dosimetric aspects (dose response, energy and dose rate dependence) and stability of these radiochromic gels initiated in preliminary works (Huet et al., 2017; Colnot et al., 2017) using spectrophotometric measurements. Moreover, by mean of optical CT scanning (Vista™), their performances to measure relative depth dose (PDD) and cross profiles were analysed. ResultsTruView™ and ClearView™ present a linear dose response up to 20 Gy and up to 80 Gy respectively, independent of both photon beam energy (4–18 MV) and dose rate (up to 9.9 Gy/min) (Huet et al., 2017; Colnot et al., 2017). ClearView™ response proves to be stable for a week post-irradiation and uniform within the batch whereas TruView™ presents an unstable but uniform response. Optical CT scanning generates errors due to stray light that need to be corrected in order to use these gels; ClearView™ scanning particularly requires important precautions. After corrections, those gels used in combination with the Vista™ scanner show promising spatial and dosimetric precision (dose difference <5%). Finally, TruView™ is reusable and presents excellent reproducible response (maximum 3% difference) and the ClearView™ dosimeter presents good spatial stability (0.5% difference after 6 days). ConclusionThis study provides important knowledge about two gel dosimeters presenting interesting dosimetric properties. A study is ongoing to benchmark those promising candidates for clinical dose verification.

P263] Monte Carlo study of unflattened versus flattened 18 MV photon beam from medical linear accelerator as photoneutron source for BNCT applications

Purpose Studies have shown the possibility of using photoneutron emissions from medical linear accelerator as in-hospital neutron source for Boron Neutron Capture Therapy (BNCT) [1] . In this study, the effect of removing the?attening filter from an 18-MV photon beam on photoneutron production was investigated using the Monte Carlo (MC) method. Methods The 18-MV photon beam of Varian 2100 linear accelerator was simulated using the EGSnrc/dosxyznrc and Geant 4 MC codes. Beam dosimetric features, including depth doses, dose profiles, photon spectra distributions, photon angular distributions, photon x-y position and planner energy fluence were calculated for flattened and unflattened 18-MV photon beams. Results The results showed that unflattened (FFF) beam has higher photon fluencies and dose rate and thus much suited for photoneutron emission. The photon fluence and relative dose for the FFF beam decrease with increasing the distance from the central axis. The amount of dose reduction at the edge of the beam increased with field size. The mean energy decreased by a factor of 1.61% and 5.4% with field size for flattened and unflattened beam, respectively. Conclusions Because of these high photon intensities, the unflattened beam considered to be more powerful for photoneutrons production compared with the flattened beam.

Natural Radiation Dose and Geomagnetic Effect

Earth keeps getting bombarded by high-energy particles that originate in the outer space and in Sun. Cosmic radiation in Earth’s atmosphere consists of a photon and directly ionizing component and a neutron component. Charged particles of cosmic radiation are deflected by the geomagnetic field that is more expressed at the equator than near the poles. Photon radiation was measured by Radiameter ESM FH 40G-L10 at 26 main meteorological stations in all parts of Croatia. The correlation between the photon dose rate and latitude was examined, as well as multiple correlations for the photon dose, latitude and altitude. The obtained positive correlation coefficients were statistically significant. The neutron component of the cosmic radiation was measured by series of nuclear track-etched detectors, at the same meteorological stations during one year period. The dependence of the neutron dose rate on the altitude was found and the associated equation of the linear regression was derived. Relation between the values of neutron dose N and altitude h, showed significant dependence of the neutron dose on altitude. However, the correlation of neutron dose and geographic (geomagnetic) latitude was not statistically significant, probably due to a small range of geographic latitudes for the measuring stations in Croatia.

53. Characterisation of TruView™: A new 3-D reusable radiochromic MethylThymol Blue based gel dosimeter for ionising radiations

Introduction Cutting-edge radiotherapy techniques deliver highly conformal treatments with steep dose gradients around the target volume. Thus, the verification of the complex resultant dose distributions presents a real dosimetric challenge requiring accurate and spatially precise dosimeters. Gel dosimetry is a promising technique as it can inform about the whole 3-D dose distribution in one irradiation and without conventional dosimeters issues [1] . This study focuses on the characterisation of the new TruView™ gel dosimeter (Modus Medical Devices Inc.). This dosimeter is based on Fricke-MTB composition [2] but presents a new MethylThymol Blue (MTB) reactive dye and a reusable structure. The dosimetric properties of this gel dosimeter and the influence of different parameters on its response are presented. Methods The key dosimetric aspects (dose response, dependence with energy and dose rate) and the TruView™ dosimeter variability with different parameters (gel temperature, light exposure, time between irradiation and reading, etc.) were studied thanks to spectrophotometric measurements. Finally, by mean of optical CT scanning (Vista™, Modus Medical Devices Inc.), its performances to measure relative depth dose (PDD) and cross profiles have been analysed. Results TruView™ presents linear response with dose up to 20 Gy independent of both photon beam energy and dose rate on the studied ranges. The study of the numerous parameters influencing its dose response enabled to determine the optimal conditions for using this gel. In those conditions, the comparison of TruView™ relative depth dose (PDD) and of cross profiles with ion chamber measurements shows a good dosimetric and spatial precision with 90% of the points passing the 3 mm 3% gamma test for the PDD and 87% for the cross profiles. Seven days after irradiation, ion diffusion inside the gel leads to return to homogeneity allowing a new irradiation to be performed. The TruView™ response presents an excellent reproducibility as 100% of the points pass the gamma test for the comparison between the PDD of the two uses and 94% for the cross profiles. Conclusions This study provides important knowledge regarding the 3-D gel dosimeter TruView™. This dosimeter presents interesting dosimetric properties but remains delicate to use due to the great response sensitivity to numerous parameters. A further study is currently ongoing to benchmark this promising candidate for clinical dose verification.

Study on variance reduction technique based on adjoint Discrete Ordinate method

For deep-penetration shielding calculation, Monte Carlo (MC) method requires simulating a great number of particles to obtain reliable results, thus huge amount of computation time is the main problem of the MC method. Source biasing and weight window technique effectively decrease the tally error of deep-penetration problem. This paper studies variance reduction techniques (VRTs) based on adjoint fluence rate from a Discrete Ordinate (SN) code JSNT, generates source biasing factors and weight window parameters for a MC code JMCT, develops source sampling subroutine for JMCT, and verifies the VRT on measurements, finally applies the VRT to reactor pressure vessel fast neutron fluence rate and cavity neutron and photon dose rate calculation. Numerical results show that the VRT increases calculation efficiency by 1–2 orders for deep-penetration shielding calculation with high precision compared with unbiased MC method.

$\gamma $ -Ray Detection Using Commercial Off-the-Shelf CMOS and CCD Image Sensors

In this paper, we present the results of research on the response of four types of commercial off-the-shelf (COTS), CMOS, and charge-coupled device (CCD) image sensors to $\gamma $ photons. The aim of this paper was to study the potential use of CCD and CMOS COTS image sensors as $\gamma $ -ray detectors. A 60Co $\gamma $ source was used to study the response behavior of the sensors to the irradiant photons. The results show that the CMOS image sensors have much less background noise before irradiation and have better radiation resistance below 51.24 Gy. The background noise of CCD sensors obviously increases with a larger total ionizing dose. The linearity of the dose-rate response of CCD COTS sensors is better than that of CMOS COTS sensors. Both mean pixel value and cumulative pixel value may be used to obtain the photon dose rate. The sensor technology structure difference leads to the different shapes of events. The Compton scattering of 60Co $\gamma $ photons in silicon caused the recorded patterns to show not only dots but also small streaks or traces. The peak value provides the photon energy, while the peak shape and radius can be used to classify the particle. CMOS COTS sensors are suitable for the particle classification, while CCD COTS sensors are better for energy resolution.

Transmutation Approximations for the Application of Hybrid Monte Carlo/Deterministic Neutron Transport to Shutdown Dose Rate Analysis

In fusion energy systems (FES) neutrons born from burning plasma activate system components. The photon dose rate after shutdown from resulting radionuclides must be quantified. This shutdown dose rate (SDR) is calculated by coupling neutron transport, activation analysis, and photon transport. The size, complexity, and attenuating configuration of FES motivate the use of hybrid Monte Carlo (MC)/deterministic neutron transport. The Multi-Step Consistent Adjoint Driven Importance Sampling (MS-CADIS) method can be used to optimize MC neutron transport for coupled multiphysics problems, including SDR analysis, using deterministic estimates of adjoint flux distributions. When used for SDR analysis, MS-CADIS requires the formulation of an adjoint neutron source that approximates the transmutation process. In this work, transmutation approximations are used to derive a solution for this adjoint neutron source. It is shown that these approximations are reasonably met for typical FES neutron spectra and materials over a range of irradiation scenarios. When these approximations are met, the Groupwise Transmutation (GT)-CADIS method, proposed here, can be used effectively. GT-CADIS is an implementation of the MS-CADIS method for SDR analysis that uses a series of single-energy-group irradiations to calculate the adjoint neutron source. For a simple SDR problem, GT-CADIS provides speedups of 200 100 relative to global variance reduction with the Forward-Weighted (FW)-CADIS method and 9 5 relative to analog. This work shows that GT-CADIS is broadly applicable to FES problems and will significantly reduce the computational resources necessary for SDR analysis.

Characterisation of TruView™: a new 3-D reusable radiochromic MethylThymolBlue based gel dosimeter for ionising radiations

TruView™ is a new water-equivalent reusable Fricke gel dosimeter based on MethylThymolBlue reactive dye. Details of the characterisation of the TruView™ MTB gel dosimeter by spectrophotometric measurements and of its reading with the Optical-CT Scanner Vista™ are described. In this study, the different parameters influencing TruView™ dose response have been studied and its performances have been compared to chamber and diodes measurements. This gel presents a linear response with dose up to 20 Gy, independent in the investigated range of photon beam energy and dose rate and also a good intra-batch uniformity. Ions diffusion into the matrix homogenizes the gel after a week, losing dosimetric information but allowing a new irradiation to be performed. However, auto-oxidation happens before and after irradiation, degrading the dosimeter response and stability. Storage and reading conditions affect the response as well.

The HMGU combined neutron and photon dosemeter

Recently, two independent electronic dosimeters for individual monitoring have been developed at the Helmholtz Center Munich, Germany, one for photons and one for neutrons. Calibration of these dosimeters was performed using mono-energetic neutrons (energy range: 144 keV–14.8 MeV) and photons (12 keV–1.3 MeV), and the resulting calibration curves were compared to Monte Carlo simulations using the GEANT4 tool kit. In the present paper, an integrated dosimeter prototype is described which combines both dosimeters and therefore allows measurement of total dose in mixed neutron/photon radiation fields. It is demonstrated that the neutron channel of the combined dosimeter is insensitive to photons, while the photon channel is insensitive to neutrons. The prototype was tested in the field of an Am-Be neutron source which also includes a photon component. When the Am-Be neutron source was shielded by 9 mm lead, the combined dosimeter indicated a dose rate of 122.6 ± 1.0 μSv/h from neutrons and 7.3 ± 0.1 μSv/h from photons. In contrast, when the Am-Be neutron source was not shielded by lead, the combined dosimeter indicated a dose rate of 125.8 ± 1.0 μSv/h from neutrons and 65.9 ± 0.1 μSv/h from photons indicating a significant contribution from photons to total dose. In a second experiment when the Am-Be neutron source was closer to the combined dosimeter and a 137Cs source was added, a neutron dose rate of 421 ± 20 μSv/h and a photon dose rate of 849 ± 6 μSv/h was obtained. It is concluded that this instrument can be used in mixed photon-neutron fields with doses and dose rates typical for radiation protection purposes.

NEUTRON AND PHOTON DOSE MAPPING OF A DD NEUTRON GENERATOR.

Neutron generators are an excellent tool that can be effectively utilized in educational institutions for applications such as neutron activation analysis, neutron radiography, and profiling and irradiation effects. For safety purposes, it is imperative that appropriate measures are taken in order to minimize the radiation dose from such devices to the operators, students and the public. This work presents the simulation and measurement results for the neutron and photon dose rates in the vicinity of the neutron generator installed at the University of Sharjah. A very good agreement is found between the simulated and measured dose rates. All of the public dose constraints were found to be met. The occupational dose constraint was also met after imposing a 200 cm no entry zone around the generator room.

Indirect measurement of field emission electron current from the main superconducting cavities of compact ERL at KEK

The field emission electron currents from the main superconducting cavities (Cavities #3 and #4) of compact ERL at KEK, Japan, were estimated indirectly from photon dose rates measured around the cavities and on the roof of the compact ERL room. The field emission electron currents estimated from the photon dose rates measured around the cavities are in good agreement with those on the roof of the compact ERL room. The field emission electron currents increased steeply with the applied voltage. The field emission electron currents corresponding to the applied voltages were different between Cavity #3 and Cavity #4. We found that the field emission electron current exceeded 1 μA at 13.5 MV for Cavity #3 and at 15.5 MV for Cavity #4. This result was used in considering unexpected loss of field emission electrons.

Activation calculation for the dismantling and decommissioning of a light water reactor using MCNP™ with ADVANTG and ORIGEN-S

The decommissioning of a light water reactor (LWR), which is licensed under § 7 of the German Atomic Energy Act, following the post-operational phase requires a comprehensive licensing procedure including in particular radiation protection aspects and possible impacts to the environment. Decommissioning includes essential changes in requirements for the systems and components and will mainly lead to the direct dismantling. In this context, neutron induced activation calculations for the structural components have to be carried out to predict activities in structures and to estimate future costs for conditioning and packaging. To avoid an overestimation of the radioactive inventory and to calculate the expenses for decommissioning as accurate as possible, modern state-of-the-art Monte-Carlo-Techniques (MCNP™) are applied and coupled with present-day activation and decay codes (ORIGEN-S). In this context ADVANTG is used as weight window generator for MCNP™ i. e. as variance reduction tool to speed up the calculation in deep penetration problems. In this paper the calculation procedure is described and the obtained results are presented with a validation along with measured activities and photon dose rates measured in the post-operational phase. The validation shows that the applied calculation procedure is suitable for the determination of the radioactive inventory of a nuclear power plant. Even the measured gamma dose rates in the post-operational phase at different positions in the reactor building agree within a factor of 2 to 3 with the calculation results. The obtained results are accurate and suitable to support effectively the decommissioning planning process.

Shielding calculations for industrial 5/7.5MeV electron accelerators using the MCNP Monte Carlo Code

High energy X-rays from accelerators are used to irradiate food ingredients to prevent growth and development of unwanted biological organisms in food, and by that extend the shelf life of the products. The production of X-rays is done by accelerating 5 MeV electrons and bombarding them into a heavy target (high Z). Since 2004, the FDA has approved using 7.5 MeV energy, providing higher production rates with lower treatments costs. In this study we calculated all the essential data needed for a straightforward concrete shielding design of typical food accelerator rooms. The following evaluation is done using the MCNP Monte Carlo code system: (1) Angular dependence (0-180°) of photon dose rate for 5 MeV and 7.5 MeV electron beams bombarding iron, aluminum, gold, tantalum, and tungsten targets. (2) Angular dependence (0-180°) spectral distribution simulations of bremsstrahlung for gold, tantalum, and tungsten bombarded by 5 MeV and 7.5 MeV electron beams. (3) Concrete attenuation calculations in several photon emission angles for the 5 MeV and 7.5 MeV electron beams bombarding a tantalum target. Based on the simulation, we calculated the expected increase in dose rate for facilities intending to increase the energy from 5 MeV to 7.5 MeV, and the concrete width needed to be added in order to keep the existing dose rate unchanged.

SU‐F‐P‐39: End‐To‐End Validation of a 6 MV High Dose Rate Photon Beam, Configured for Eclipse AAA Algorithm Using Golden Beam Data, for SBRT Treatments Using RapidArc

Purpose:To use end‐to‐end testing to validate a 6 MV high dose rate photon beam, configured for Eclipse AAA algorithm using Golden Beam Data (GBD), for SBRT treatments using RapidArc.Methods:Beam data was configured for Varian Eclipse AAA algorithm using the GBD provided by the vendor. Transverse and diagonals dose profiles, PDDs and output factors down to a field size of 2×2 cm2 were measured on a Varian Trilogy Linac and compared with GBD library using 2% 2mm 1D gamma analysis. The MLC transmission factor and dosimetric leaf gap were determined to characterize the MLC in Eclipse. Mechanical and dosimetric tests were performed combining different gantry rotation speeds, dose rates and leaf speeds to evaluate the delivery system performance according to VMAT accuracy requirements. An end‐to‐end test was implemented planning several SBRT RapidArc treatments on a CIRS 002LFC IMRT Thorax Phantom. The CT scanner calibration curve was acquired and loaded in Eclipse. PTW 31013 ionization chamber was used with Keithley 35617EBS electrometer for absolute point dose measurements in water and lung equivalent inserts. TPS calculated planar dose distributions were compared to those measured using EPID and MapCheck, as an independent verification method. Results were evaluated with gamma criteria of 2% dose difference and 2mm DTA for 95% of points.Results:GBD set vs. measured data passed 2% 2mm 1D gamma analysis even for small fields. Machine performance tests show results are independent of machine delivery configuration, as expected. Absolute point dosimetry comparison resulted within 4% for the worst case scenario in lung. Over 97% of the points evaluated in dose distributions passed gamma index analysis.Conclusion:Eclipse AAA algorithm configuration of the 6 MV high dose rate photon beam using GBD proved efficient. End‐to‐end test dose calculation results indicate it can be used clinically for SBRT using RapidArc.

Real-time dosimetry in radiotherapy using tailored optical fibers

Real-time dosimetry plays an important role for accurate patient-dose measurement during radiotherapy. A tiny piece of laboratory fabricated Ge-doped optical fiber has been investigated as a radioluminescence (RL) sensor for real-time dosimetry over the dose range from 1 Gy to 8 Gy under 6 MV photon beam by LINAC. Fiber-coupled software-based RL prototype system was used to assess essential dosimetric characteristics including dose response linearity, dose rate dependency, sensitivity, repeatability and output dependence on field sizes. The consistency level of RL photon counts versus dose rate was also compared with that of standard Al2O3:C chips. Sensitivity of Ge-doped fiber were found to be sufficiently sensitive for practical use and also provided linear dose responses for various dose rates from 100 cGy/min to 600 cGy/min using both 6 MV photon and 6 MeV electron beams. SEM-EDX analysis was performed to identify Ge-dopant concentration level within the optical fiber RL material. Accumulated doses were also estimated using simple integral technique and the error was found to be around less than 1% under dissimilar dose rates or repeat measurements. The evaluation of the Ge-doped optical fiber based RL dosimeter system indicates its potential in medical dosimetry.

Optimal moderator materials at various proton energies considering photon dose rate after irradiation for an accelerator-driven 9Be(p, n) boron neutron capture therapy neutron source

We evaluated the accelerator beam power and the neutron-induced radioactivity of 9Be(p, n) boron neutron capture therapy (BNCT) neutron sources having a MgF2, CaF2, or AlF3 moderator and driven by protons with energy from 8MeV to 30MeV. The optimal moderator materials were found to be MgF2 for proton energies less than 10MeV because of lower required accelerator beam power and CaF2 for higher proton energies because of lower photon dose rate at the treatment position after neutron irradiation.

WE-AB-BRB-11: Portable Fast Neutron and Photon Dose Meter

Purpose: To develop an instrument for measuring neutron and photon dose rates from mixed fields with a single device. Methods: Stilbene organic scintillators can be used to detect fast neutrons and photons. Stilbene was used to measure emission from mixed particle sources californium-252 (Cf-252) and plutonium-beryllium (PuBe). Many source detector configurations were used, along with varying amounts of shielding. Collected spectra were analyzed using pulse shape discrimination software, to separate neutron and photon interactions. With a measured light output to energy relationship the pulse height spectrum was converted to energy deposited in the detector. Energy deposited was converted to dose with a variety of standard dose factors, for comparison to current methods. For validation, all measurements and processing was repeated using an EJ-309 liquid scintillator detector. Dose rates were also measured in the same configuration with commercially available dose meters for further validation. Results: Measurements of dose rates will show agreement across all methods. Higher accuracy of pulse shape discrimination at lower energies with stilbene leads to more accurate measurement of neutron and photon deposited dose. In strong fields of mixed particles discrimination can be performed well at a very low energy threshold. This shows accurate dose measurements over a large range of incident particle energy. Conclusion: Stilbene shows promise as a material for dose rate measurements due to its strong ability for separating neutrons and photon pulses and agreement with current methods. A dual particle dose meter would simplify methods which are currently limited to the measurement of only one particle type. Future work will investigate the use of a silicon photomultiplier to reduce the size and required voltage of the assembly, for practical use as a handheld survey meter, room monitor, or phantom installation. Funding From the United States Department of Energy and the National Nuclear Security Administration.