Underground measurements on secondary cosmic rays

Measurements made at the Poatina cosmic ray station (41.8 S 149.9 E, 347 m.w.e.) from August 1983 to July 1984 are summarized. The cosmic ray primary particles responsible for events detected at the station have a median primary energy of 1.2 TeV. The motivation for part of this work came from the reported detection of narrow angle anisotropies in the arrival direction of cosmic rays

Long-term modulation of cosmic rays during solar cycle 21

A preliminary result concerning the rigidity dependence of the longer-term solar cycle modulation is reported. The long-term modulation, using monthly mean intensities and referred to November 1977 as a normalizing level, appear to be in accordance with the exponent gamma = 1, provided only Brisbane and Hobart data are used. Darwin data do not conform to this pattern except perhaps during the early years of the cycle until about the end of 1980, since when the Darwin long-term intensity has been largely steady, apart from Forbush-type decreases and the as yet unidentified vector from the observed SI vector. The true SI vector of galactic origin can be obtained. The resultant vector has the amplitude of 0.031% and the phase of 2.3h. The present result seems to be consistent with those so far reported

Energetic solar particle events

Studies of the arrival directions of energetic solar particles during ground level enhancements (CLE's) observed by neutron monitors have shown that, in general, in the first hour of the event most of the particles arrive with a distribution of pitch angles peaked about the garden hose field direction in the vicinity of Earth. During the first hour some of the particles arrive from the antisolar direction, while in later stages of the event the intensity becomes more nearly isotropic as a result of scattering of particles in interplanetary space. An attempt is made to determine the arrival directions of the particles during the early stages of the GLE of 16 February 1984 using the data currently available from high latitude neutron monitors near sea level where the cut off is essentially atmospheric (approx. LGV)

Sidereal variations deep underground in Tasmania

Data from the deep underground vertically directed muon telescopes at Poatina, Tasmania, have been used since 1972 for a number of investigations, including the daily intensity variations, atmospheric influences, and checking for possible effects due to the interplanetary magnetic field. These telescopes have a total sensitive area of only 3 square meters, with the result that the counting rate is low (about 1680 events per hour) and the statistical errors on the results are rather large. Consequently, it was decided several years ago to construct larger detectors for this station. The first of these telescopes has been in operation for two complete years, and the results from it are presented. Results from the new, more stable equipment at Poatina appear to confirm the existence of a first harmonic in the daily variations in sidereal time reported earlier, and are consistent with small or non-existent first harmonics in solar and anti-sidereal time. All the second harmonics appear to be small, if not zero at these energies

Atmospheric effects on the underground muon intensity

It has previously been reported that the barometric pressure coefficient observed for muons at Poatina (vertical absorber depth 357 hg/sq cm) appears to be appreciably higher than would be expected from atmospheric absorption alone. There is a possibility that the effect is due to an upper atmospheric temperature effect arising from an inverse correlation of surface pressure with stratospheric temperature. A new proportional telescope is discussed which has been operating at Poatina since about the beginning of 83 and which has a long term stability suitable for studying variations of atmospheric origin

Learning about sex: Results from Natsal 2000.

11-13 September 2002

Master of Science

thesisAtmospheric methane and carbon dioxide have been deemed significant "greenhouse gases" (GHG) which are thought to be responsible for major climate changes. Wastewater treatment plants have seen quite a lot of attention with respect to methane release, but little study of sewer transport (pipeline) contribution has been reflected in recent literature. This lack of analysis on sewer systems could be because of the Intergovernmental Panel on Climate Change report stating that in most developed countries, sewers are closed and underground, and therefore would not make a large contribution to carbon emissions (especially CH4) emissions. Previous methods for quantifying sewer transport emissions have mainly utilized tracer gas coupled with measurement of flow or velocity rates within the sewer lines, or through lab studies. The purpose of this study was to develop a direct flux emissions measurement method based on existing technology, soil flux chambers, for CH4 and CO2 using lab calibration and field testing. Such chambers were designed for measuring diffuse soil fluxes exclusively, and decades of such measurements indicate the validity of the approach. In this thesis study, the soil chamber was used as a basis for designing a larger chamber capable of handling relatively larger magnitude point fluxes from sewer access covers. The University of Utah campus consists of a series of mixed gravity sewer designs and ages, spanning the past century. Assuming this system was representative of the range of urban gravity sewer infrastructure typical to U.S. cities, a case study was done as part of this thesis. For this work, 11 sewer access covers were analyzed using a specifically designed flux chamber to measure gas fluxes directly from the sewer access covers. Based on these surveys, a preliminary estimate of annual carbon emissions from these 11 access iv points was determined to be 1.066 Metric Tons CO2 equivalent per year (Mt CO2e). It is recommended that more calibration and continuous surveys of these, and all other sewer access points on campus, are done to facilitate the calculation and cumulative "carbon footprint" of the campus sewer system. Ultimately, the technology developed as part of this thesis work can form the basis of an effective methodology to measure CH4 and CO2 emissions from sewer lines and possibly other urban infrastructure, and quantify the relative major GHG emissions or "carbon footprint" of such emission sources