Bubble detector characterization for space radiation

Green, A.R.; Andrews, H. R.; Bennett, L. G. I.; Clifford, E. T. H.; Ing, H.; Jonkmans, G.; Lewis, Brent J.; Noulty, R.; Ough, Edward A.

doi:10.1016/j.actaastro.2005.01.022

Cited by 15 publications

(10 citation statements)

References 17 publications

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“…The expected peaks at around 1 MeV and above 10 MeV are observed in the data from all four USOS locations. These characteristic features have been observed in earlier work using bubble detectors (3 -5, 7, 8) and other instruments (11,15) deployed in aircraft and spacecraft. The limited counting statistics of a single week-long measurement (discussed earlier in this article) are apparent in the data shown in Figure 1.…”

Section: Resultssupporting

confidence: 71%

“…This scaling factor accounts for the difference between the AmBe energy spectrum and the spectrum expected in space. It was determined using theoretical calculations of the bubble-detector response and measurements that validated these calculations (5,11,12) . Following this procedure, the dosimetric quantity reported by bubble detectors in the space environment is the ambient dose equivalent, H* (10).…”

Section: Bubble Detector Calibrationmentioning

confidence: 99%

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Bubble-Detector Measurements of Neutron Radiation in the International Space Station: Iss-34 to Iss-37

Smith¹,

Khulapko

Andrews³

et al. 2015

Radiat Prot Dosimetry

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Bubble detectors have been used to characterise the neutron dose and energy spectrum in several modules of the International Space Station (ISS) as part of an ongoing radiation survey. A series of experiments was performed during the ISS-34, ISS-35, ISS-36 and ISS-37 missions between December 2012 and October 2013. The Radi-N2 experiment, a repeat of the 2009 Radi-N investigation, included measurements in four modules of the US orbital segment: Columbus, the Japanese experiment module, the US laboratory and Node 2. The Radi-N2 dose and spectral measurements are not significantly different from the Radi-N results collected in the same ISS locations, despite the large difference in solar activity between 2009 and 2013. Parallel experiments using a second set of detectors in the Russian segment of the ISS included the first characterisation of the neutron spectrum inside the tissue-equivalent Matroshka-R phantom. These data suggest that the dose inside the phantom is ∼70% of the dose at its surface, while the spectrum inside the phantom contains a larger fraction of high-energy neutrons than the spectrum outside the phantom. The phantom results are supported by Monte Carlo simulations that provide good agreement with the empirical data.

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Section: Resultssupporting

confidence: 71%

Section: Bubble Detector Calibrationmentioning

confidence: 99%

Bubble-Detector Measurements of Neutron Radiation in the International Space Station: Iss-34 to Iss-37

Smith¹,

Khulapko

Andrews³

et al. 2015

Radiat Prot Dosimetry

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“…Therefore, nucleation is expected to be induced by heavy recoil nuclei generated by nonelastic interactions of protons with the phantom matrix or the nanodroplets themselves, as well as by similarly released alpha particles, whose LET lie in the range 130–190 keV/µm, 62 for the 37°C case. At 50°C, the predicted threshold drops further down to 60 keV/µm, allowing sensitization to primary protons that reach an LET up to 70–90 keV/µm at the very end of their range, 63 while being too high to observe vaporization induced by secondary electrons (LET of 25–30 keV/µm 31 ). This sensitization to the primary proton beam is clearly demonstrated by the strong contrast increase at the end of the vaporization curves and could even be observed visually (Figs.…”

Section: Discussionmentioning

confidence: 99%

Modulating ultrasound contrast generation from injectable nanodroplets for proton range verification by varying the degree of superheat

et al. 2021

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Purpose: Despite the physical benefits of protons over conventional photon radiation in cancer treatment, range uncertainties impede the ability to harness the full potential of proton therapy. While monitoring the proton range in vivo could reduce the currently adopted safety margins, a routinely applicable range verification technique is still lacking. Recently, phase-change nanodroplets were proposed for proton range verification, demonstrating a reproducible relationship between the proton range and generated ultrasound contrast after radiation-induced vaporization at 25°C. In this study, previous findings are extended with proton irradiations at different temperatures, including the physiological temperature of 37°C, for a novel nanodroplet formulation. Moreover, the potential to modulate the linear energy transfer (LET) threshold for vaporization by varying the degree of superheat is investigated, where the aim is to demonstrate vaporization of nanodroplets directly by primary protons. Methods: Perfluorobutane nanodroplets with a shell made of polyvinyl alcohol (PVA-PFB) or 10,12-pentacosadyinoic acid (PCDA-PFB) were dispersed in polyacrylamide hydrogels and irradiated with 62 MeV passively scattered protons at temperatures of 37°C and 50°C. Nanodroplet transition into echogenic microbubbles was assessed using ultrasound imaging (gray value and attenuation analysis) and optical images. The proton range was measured independently and compared to the generated contrast. Results: Nanodroplet design proved crucial to ensure thermal stability, as PVA-shelled nanodroplets dramatically outperformed their PCDA-shelled counterpart. At body temperature, a uniform radiation response proximal to the Bragg peak is attributed to nuclear reaction products interacting with PVA-PFB nanodroplets, with the 50% drop in ultrasound contrast being 0.17 mm AE 0.20 mm 1983

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“…Unfortunately, the degree of superheat of PFB is below the sensitization threshold for protons at the physiological temperature of 37°C [12]. Previously, the degree of superheat of bubble chambers and superheated drop detectors was tuned by modifying the ambient temperature [30], [31], the static ambient pressure [32], or by using superheated liquids with different boiling temperatures [33], [34]. While the first two options are unfeasible in an in vivo application, the last option also suffers from several limitations.…”

Section: Introductionmentioning

confidence: 99%

Acoustic Modulation Enables Proton Detection With Nanodroplets at Body Temperature

Heymans

Collado-Lara

Rovituso³

et al. 2022

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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Superheated nanodroplet vaporization by proton radiation was recently demonstrated, opening the door to ultrasound-based in vivo proton range verification. However, at body temperature and physiological pressures, perfluorobutane nanodroplets (PFB-NDs), which offer a good compromise between stability and radiation sensitivity, are not directly sensitive to primary protons. Instead, they are vaporized by infrequent secondary particles, which limits the precision for range verification. The radiation-induced vaporization threshold (i.e. sensitization threshold) can be reduced by lowering the pressure in the droplet such that nanodroplet vaporization by primary protons can occur. Here, we propose to use an acoustic field to modulate the pressure, intermittently lowering the proton sensitization threshold of PFB-NDs during the rarefactional phase of the ultrasound wave. Simultaneous proton irradiation and sonication with a 1.1 MHz focused transducer, using increasing peak negative pressures (PNPs), were applied on a dilution of PFB-NDs flowing in a tube, while vaporization was acoustically monitored with a linear array. Sensitization to primary protons was achieved at temperatures between 29 and 40°C using acoustic PNPs of relatively low amplitude (from 800 kPa to 200 kPa, respectively), while sonication alone did not lead to ND vaporization at those PNPs. Sensitization was also measured at the clinically relevant body temperature (i.e., 37°C) using a PNP of 400 kPa. These findings confirm that acoustic modulation lowers the sensitization threshold of superheated nanodroplets, enabling a direct proton response at body temperature.

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Bubble detector characterization for space radiation

Cited by 15 publications

References 17 publications

Bubble-Detector Measurements of Neutron Radiation in the International Space Station: Iss-34 to Iss-37

Bubble-Detector Measurements of Neutron Radiation in the International Space Station: Iss-34 to Iss-37

Modulating ultrasound contrast generation from injectable nanodroplets for proton range verification by varying the degree of superheat

Acoustic Modulation Enables Proton Detection With Nanodroplets at Body Temperature

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