Browsing by Author "Ferris, JM"
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- ItemDielectric properties and photoluminescence of diatomaceous silicas(Australian Institute of Physics, 2005-01-31) Jong Wah, JW; Ferris, JM; Wintrebert-Fouquet, M; Butcher, KSASilica shells produced by diatoms have been studied to investigate their potential for applications in electronic and photonic devices due to their dielectric and photoluminescent properties. Dielectric measurements for low (1k-1MHz) and high (∼1GHz) frequencies were performed on processed diatomaceous earth samples and compared with measurements for artificial porous silica samples. Photoluminescence spectra for a sample of freshwater benthic diatoms were obtained and compared with silica spectra. The ratio of the 3.2eV photoluminescence peak compared to a peak at ∼2.20eV is smaller than for pure fused silica, and there is evidence of extra shoulder peak near 2.2eV for diatogenic silica. © 2005 Australian Institute of Physics.
- ItemEnvironmental and effluent monitoring at ANSTO sites, 2002-2003(Australian Nuclear Science and Technology Organisation, 2003-06) Hoffmann, EL; Ferris, JM; Markich, SJThis report presents the results of environmental and effluent monitoring at the Lucas Heights Science and Technology Centre (LHSTC) and the National Medical Cyclotron (NMC) from January 2002 to June 2003. Potential effective dose rates to the general public from airborne discharges from the LHSTC site were less than 0.01 mSv/year, well below the 1 mSv/year dose rate limit for long term exposure that is recommended by the Australian National Occupational Health and Safety Commission. The effective dose rates to hypothetical individuals potentially exposed to radiation in routine liquid effluent discharges from the LHSTC were recently calculated to be less than 0.001 mSv/year. This is much less than dose rates estimated for members of public potentially exposed to airborne emissions. The levels of tritium detected in groundwater and stormwater at the LHSTC were less than the Australian drinking water guidelines. The airborne and liquid effluent emissions from the NMC were below the ARPANSA-approved notification levels and NSW EPA limits, respectively. ANSTO's routine operations at the LHSTC and the NMC make only a very small addition to the natural background radiation dose experienced by members of the Australian public.
- ItemEnvironmental and effluent monitoring at ANSTO sites, 2004-2005(Australian Nuclear Science and Technology Organisation, 2005-11) Hoffmann, EL; Loosz, T; Ferris, JM; Harrison, JJThis report presents the results of ANSTO's environmental and effluent monitoring at the Lucas Heights Science and Technology Centre (LHSTC) and the National Medical Cyclotron (NMC) sites, from July 2004 to June 2005. Effective doses to the critical group of members of the public potentially affected by routine airborne emissions from the LHSTC were less than 0.005 mSv/year. This estimated maximum potential dose is less than 24% of the ANSTO ALARA objective of 0.02 mSv/year, and much lower than the public dose limit of 1 mSv/year that is recommended by the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA). The effective doses to the critical group of members of the public potentially exposed to routine liquid effluent releases from the LHSTC have been realistically estimated as a quarter (or less) of the estimated doses to the critical group for airborne releases. The levels of tritium detected in groundwater and stormwater at the LHSTC were less than those set out in the Australian Drinking Water Guidelines. The airborne and liquid effluent emissions from the NMC were below both the ARPANSA-approved notification levels and Sydney Water limits for acceptance of trade wastewater to sewer. Results of environmental monitoring at both ANSTO sites confirm that the facilities continue to be operated well within regulatory limits. ANSTO's routine operations at the LHSTC and NMC make only a very small addition to the natural background radiation dose of ~1.5 mSv/year experienced by members of the Australian public.
- ItemEnvironmental and effluent monitoring at ANSTO sites, 2005-2006(Australian Nuclear Science and Technology Organisation, 2007-03) Hoffmann, EL; Loosz, T; Ferris, JM; Harrison, JJThis report presents the results of ANSTO's environmental and effluent monitoring at Lucas Heights Science and Technology Centre (LHSTC) and the National Medical Cyclotron (NMC) sites, from July 2005 to June 2006. Estimated effective doses to the critical group of members of the public potentially affected by routine airborne emissions from the LHSTC were less that 0.005 mSv/year. The maximum potential dose was 23% of the ANSTO ALARA objective of 0.02 mSv/year, much lower than the public dose limit of 1mSv/year that is recommended by the Australian Radiation Protection and Nuclear Safety Authority (ARPANSA). The effective doses to the critical groups of members of the public potentially exposed to routine liquid effluent releases from the LHSTC have been realistically estimated as a quarter (or less) of the estimated doses to the critical group for airborne releases. The medium tritium concentrations detected in groundwater and surface waters at the LHSTC were typically less than 2% of those set out in the Australian Drinking Water Guidelines. The airborne emissions from the NMC were below the ARPANSA-approved notification levels. Results of environmental monitoring at both ANSTO sites confirm that the facilities continue to be operated well within regulatory limits. ANSTO's routine operations at the LHSTC and NMC make only a very small addition to the natural background radiation dose of ~1.5 mSv/year experienced by members of the Australian public.
- ItemEnvironmental and effluent monitoring at ANSTO sites, 2006-2007(Australian Nuclear Science and Technology Organisation, 2008-03) Hoffmann, EL; Loosz, T; Ferris, JMThis report presents the results of ANSTO’s environmental and effluent monitoring at the Lucas Heights Science and Technology Centre (LHSTC) and the National Medical Cyclotron (NMC) sites, from July 2006 to June 2007. Estimated effective doses to the members of the public potentially affected by routine airborne emissions from the LHSTC were lower than in previous years due to the closure of the HIFAR research reactor. The maximum potential off-site dose of 0.002 mSv/year was 10% of the As Low As Reasonably Achievable (ALARA) objective of 0.02 mSv/year, and much lower than the public dose limit of 1 mSv/year that is recommended by the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA). The effective doses to the critical group potentially exposed to routine liquid effluent releases from the LHSTC have been realistically assessed at less than 25% of the estimated doses to the critical group for airborne releases. Based on releases of liquid effluent from the LHSTC during 2006-07, a radiological risk assessment was conducted for marine biota in the receiving environment at Potter Point. The possible dose-rates to various species of marine biota were evaluated against international criteria recommended for the protection of biota from radiological hazards. In all cases it was concluded that the radiological risk to marine biota from ANSTO’s effluent releases was negligible. The median tritium concentrations detected in groundwater and surface waters at the LHSTC were typically less than 2% of those set out in the Australian Drinking Water Guidelines. The airborne emissions from the NMC were below the ARPANSA-approved notification levels. Results of environmental monitoring at both ANSTO sites confirm that the facilities continue to be operated well within regulatory limits. ANSTO’s routine operations at the LHSTC and NMC make only a very small addition to the natural background radiation dose of approximately 1.5 mSv/year experienced by members of the Australian public.
- ItemEnvironmental and effluent monitoring at ANSTO sites: 2003-2004(Australian Nuclear Science and Technology Organisation, 2004-10) Hoffmann, EL; Ferris, JM; Harrison, JJ; Loosz, TThis report presents the results of ANSTO's environmental and effluent monitoring at the Lucas Heights Science and Technology Centre (LHSTC) and the National Medical Cyclotron (NMC) sites, from July 2003 to June 2004. Effective doses to the critical group of members of the public potentially affected by routine airborne emissions from the LHSTC were less than 0.004 mSv/year. This estimated maximum potential dose is less than 20% of the ANSTO ALARA objective of 0.02 mSv/year and much lower than the public dose limit of 1 mSv/year that is recommended by the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA). The effective doses to the critical group of members of the public potentially exposed to routine liquid effluent releases from the LHSTC have been realistically estimated as a quarter (or less) of the estimated doses to the critical group for airborne releases. The levels of tritium detected in groundwater and stormwater at the LHSTC were less than the Australian Drinking Water Guidelines. The airborne and liquid effluent emissions from the NMC were below the ARPANSA-approved notification levels and NSW Department of Environment and Conservation limits, respectively. Results of environmental monitoring at both ANSTO sites confirm that the facilities continue to be operated well within regulatory limits. Members of the public are exposed to only very small doses of radiation from ANSTO's routine airborne and liquid effluent releases.
- ItemEnvironmental monitoring at the Australian Nuclear Science & Technology Organisation (ANSTO)(International Atomic Energy Agency, 2004-10-24) Ferris, JM; Harrison, JJ; Hoffmann, EL; Payne, TE; Szymczak, RThe Australian Nuclear Science and Technology Organisation (ANSTO) operates several facilities, including Australia’s only research reactor, HIFAR, carrying out production of radiopharmaceuticals and research in nuclear science and technology. ANSTO is an agency of the Commonwealth of Australia. Most ANSTO facilities are at the Lucas Heights Science and Technology Centre (LHSTC), surrounded by a 1.6 km buffer zone, about 40 km southwest of Sydney. ANSTO also operates the National Medical Cyclotron (NMC), located on the grounds of Royal Prince Alfred Hospital in Camberdown, Sydney, which produces shortlived radioisotopes for medical investigations. ANSTO is committed to undertaking its activities in a manner that protects human health and the environment and is consistent with national and international standards and our activities are regulated by the Australian Radiation Protection and Nuclear Safety Agency [1] under the Australian Radiation Protection and Nuclear Safety Act (1998). ANSTO has a comprehensive monitoring programme for the main pathways for potential exposure from routine and accidental releases for radioactivity. Annually, approximately 6000 samples are taken and some 10,000 analyses are performed. ANSTO monitors the amounts of airborne emissions, the radioactive and non-radioactive contaminants released to the sewer and subsequently to local coastal waters, the quality of stormwater leaving the site, the quality of groundwater and soils and sediment in the general vicinity. The principal sources of potential radiation exposure to members of the general public from routine ANSTO operations at the LHSTC and National Medical Cyclotron are from airborne emissions and low- level liquid effluent discharges. The effective dose rate to a hypothetical individual potentially exposed to radiation in routine airborne discharges from the LHSTC during the 2002-03 fiscal year was less than 0.006 mSv/year, based on stack discharge data and concurrent meteorological information. This effective dose is well below the ALARA objective of 0.02 mSv/year and less than 1% of the public dose rate limit of 1 mSv/year for long term exposure that is recommended by the Australian Occupational Health and Safety Commission. It is also less than 1% of the natural background annual dose in Australia of about 1.5 mSv/year [2]. Thermoluminescent dosimeters placed around the LHSTC and at some local residences also demonstrate that the external gamma radiation levels at residential locations in the vicinity of the LHSTC were at normal background levels and not noticeably affected by ANSTO operations. ANSTO operations at the LHSTC and the NMC make only a very small addition to the background radiation dose, even for the comparatively few members of the public identified as potentially exposed to radionuclides entering the environment from the ANSTO sites. The results of the monitoring programme are published annually in documents within the series Environmental and Effluent Monitoring at ANSTO Sites [3 and references therein], copies of which are available in the local Sutherland Shire Central Library and on request from the ANSTO Communications Manager. The environmental and effluent monitoring programme at ANSTO is very much a team effort and acknowledgment goes to all associated staff for their valuable contributions.
- ItemEnvironmental monitoring at the Australian Nuclear Science & Technology Organisation (ANSTO)(International Atomic Energy Agency, 2006) Ferris, JM; Harrison, JJ; Hoffmann, EL; Payne, TE; Szymczak, RThe Australian Nuclear Science and Technology Organisation (ANSTO) operates several facilities, including Australia’s only research reactor, HIFAR, carrying out production of radiopharmaceuticals and research in nuclear science and technology. ANSTO is an agency of the Commonwealth of Australia. Most ANSTO facilities are at the Lucas Heights Science and Technology Centre (LHSTC), surrounded by a 1.6 km buffer zone, about 40 km southwest of Sydney. ANSTO also operates the National Medical Cyclotron (NMC), located on the grounds of Royal Prince Alfred Hospital in Camberdown, Sydney, which produces shortlived radioisotopes for medical investigations. ANSTO is committed to undertaking its activities in a manner that protects human health and the environment and is consistent with national and international standards and our activities are regulated by the Australian Radiation Protection and Nuclear Safety Agency [1] under the Australian Radiation Protection and Nuclear Safety Act (1998). ANSTO has a comprehensive monitoring programme for the main pathways for potential exposure from routine and accidental releases for radioactivity. Annually, approximately 6000 samples are taken and some 10,000 analyses are performed. ANSTO monitors the amounts of airborne emissions, the radioactive and non-radioactive contaminants released to the sewer and subsequently to local coastal waters, the quality of stormwater leaving the site, the quality of groundwater and soils and sediment in the general vicinity. The principal sources of potential radiation exposure to members of the general public from routine ANSTO operations at the LHSTC and National Medical Cyclotron are from airborne emissions and low- level liquid effluent discharges. The effective dose rate to a hypothetical individual potentially exposed to radiation in routine airborne discharges from the LHSTC during the 2002-03 fiscal year was less than 0.006 mSv/year, based on stack discharge data and concurrent meteorological information. This effective dose is well below the ALARA objective of 0.02 mSv/year and less than 1% of the public dose rate limit of 1 mSv/year for long term exposure that is recommended by the Australian Occupational Health and Safety Commission. It is also less than 1% of the natural background annual dose in Australia of about 1.5 mSv/year [2]. Thermoluminescent dosimeters placed around the LHSTC and at some local residences also demonstrate that the external gamma radiation levels at residential locations in the vicinity of the LHSTC were at normal background levels and not noticeably affected by ANSTO operations. ANSTO operations at the LHSTC and the NMC make only a very small addition to the background radiation dose, even for the comparatively few members of the public identified as potentially exposed to radionuclides entering the environment from the ANSTO sites. The results of the monitoring programme are published annually in documents within the series Environmental and Effluent Monitoring at ANSTO Sites [3 and references therein], copies of which are available in the local Sutherland Shire Central Library and on request from the ANSTO Communications Manager. The environmental and effluent monitoring programme at ANSTO is very much a team effort and acknowledgment goes to all associated staff for their valuable contributions.
- ItemLuminescence study of porous diatoms(Elsevier, 2005-12) Butcher, KSA; Ferris, JM; Phillips, MR; Wintrebert-Fouquet, M; Jong Wah, JW; Jovanovic, N; Vyverman, W; Chepurnov, VAThe cathodoluminescent and photoluminescent properties of the nanoporous silica frustules of various diatom strains and of natural diatom samples are presented. The spectra are observed to be similar to that of pure silica glass and the phenology is therefore believed to also be somewhat similar. A strong U-V-blue luminescence peak is commonly observed as well as a yellow peak at 2.15 eV For the more heavily silicified field-collected freshwater benthic samples, a strong red peak at 1.95 eV is also observed. The 2.15 eV peak is also more strongly evident for the field-collected samples. The U-V-blue peak is related to common silica defect structure but cathodoluminescent microanalysis shows that this emission is highly localized in the diatom samples. © 2005, Elsevier Ltd.
- ItemA luminescence study of porous diatoms(European Materials Research Society, 2004-05) Butcher, KSA; Ferris, JM; Phillips, MR; Wintrebert-Fouquet, M; Jong Wah, JW; Jovanovic, N; Vyverman, W; Chepurnov, VA
- ItemPhotoluminescence and cathodoluminescence studies of diatoms - nature’s own nano-porous silica structures(Australian and New Zealand Institute of Physics, 2003-02) Butcher, KSA; Ferris, JM; Phillips, MRPhotoluminescence (PL) and cathodoluminescence (CL) data are presented for the silica frustules of some fresh water diatoms. The diatom frustules consist of a nano-porous silica structure that may possibly be exploited for optoelectronic or photonic applications. This work represents what we believe to be the first report of the CL and PL properties of this naturally occurring source of nano-porous silica.
- ItemSmall angle neutron scattering (SANS) and TEM studies of the internal porosity of three cultured diatom frustules(Commission for Biological Physics, 2004-08) Garvey, CJ; Ferris, JMDiatoms are microscopic algae that produce intricate silica cell walls, called frustules. These structures have well-defined pore classes that characterise the species of diatom. In this way a particular species is able to produce porous silica containing several highly monodisperse pore sizes. The ability to culture relatively large amounts of diatom frustules supports the investigation of pore size distribution in bulk samples with a small angle scattering technique. In this work, we compare SANS scattering curves for three species of diatoms with internal porosity visualised from frustule sections examined under TEM. We comment on the relative merits of each approach for determining the internal porosity of diatom frustules.
- ItemSmall angle neutron scattering on an absolute intensity scale and the internal surface of diatom frustules from three species of differing morphologies(Springer, 2013-05-01) Garvey, CJ; Strobl, M; Percot, A; Šaroun, J; Haug, J; Vyverman, W; Chepurnov, VA; Ferris, JMThe internal nanostructure of the diatoms Cyclotella meneghiniana, Seminavis robusta and Achnanthes subsessilis was investigated using small angle neutron scattering (SANS) to examine thin biosilica samples, consisting of isotropic (powder) from their isolated cell walls. The interpretation of SANS data was assisted by several other measurements. The N-2 adsorption, interpreted within the Branuer-Emmet-Teller isotherm, yielded the specific surface area of the material. Fourier transform infrared (FTIR) and Raman spectroscopy indicates that the isolated material is amorphous silica with small amounts of organic cell wall materials acting as a filling material between the silica particles. A two-phase (air and amorphous silica) model was used to interpret small angle neutron scattering data. After correction for instrumental resolution, the measurements on two SANS instruments covered an extended range of scattering vectors 0.0011 nm(-1) < q < 5.6 nm(-1), giving an almost continuous SANS curve over a range of scattering vectors, q, on an absolute scale of intensity for each sample. Each of the samples gave a characteristic scattering curve where log (intensity) versus log (q) has a -4 dependence, with other features superimposed. In the high-q regime, departure from this behaviour was observed at a length-scales equivalent to the proposed unitary silica particle. The limiting Porod scattering law was used to determine the specific area per unit of volume of each sample illuminated by the neutron beam. The Porod behaviour, and divergence from this behaviour, is discussed in terms of various structural features and the proposed mechanisms for the bio-assembly of unitary silica particles in frustules. © 2013, Springer.