Upper limit for the solar neutron flux in the energy interval 20–120 MeV

An experiment has been performed to search for the existence of a flux of solar neutrons at the earth using a detector sensitive to neutrons in the energy region 20–120 MeV. The instrument was carried by balloon to an atmospheric depth of 4 g/cm², from Palestine, Texas on the morning of November 2, 1967 and flown through sunrise and for about 7 hours into the day. Numerous flares of importance 1B or less occurred during the float period. By comparison of night and day counting rates we have deduced that the upper limit to the continuous emission of solar neutrons at the earth is 2 × 10^–2 neutrons/cm² sec in the above energy region. Using a theoretical form for the neutron differential energy spectrum we have expressed this result as an upper limit differential solar neutron flux. If neutrons were emitted in association with any of the small flares then the maximum flux at the earth was less than 4 × 10^–2 neutron/cm² sec in the same energy region. The minimum detectable flux with the present instrument is therefore well below the predicted flux from a 3B flare (e.g., Nov. 12, 1960) of 550 neutrons/cm² sec.     

Observations of solar gamma ray continuum between 360 keV and 7 MeV on August 4, 1972

Measurements were made of the time-averaged gamma ray energy loss spectrum in the energy range 360 keV to 7 MeV by the gamma ray detector on the OSO-7 satellite during the 3B flare on August 4, 1972. The differential photon spectrum unfolded from this spectrum after subtracting the background spectrum and contributions from gamma ray lines is best described by a power law with spectral index of 3.4±0.3 between 360–700 keV and by an exponential law of the form exp (-E/E ₀) with E ₀ = 1.0±0.1 MeV above 700 keV. It is suggested that this spectrum is due to nonthermal electron bremsstrahlung from a population of electrons, with a strong break in the spectrum at 2 MeV. Since the observational data indicates that the matter number density must be n _H ? 5 × 10¹⁰ cm^-3 in the production region, the number of electrons above 100 keV required to explain the results is ?2 × 10³⁴.     

CATSAT - a very low cost burst distance measuring mission

CATSAT is a small, fast and cheap space mission currently funded for Phase A studies under the Student Explorer Demonstration Initiative (STEDI) by University Space Research Association. Its prime scientific objective is to determine burst distances by measuring their spectra at energies from < 500 eV to several MeV. Soft X-ray spectral measurements will be made with 2 cm² Si Avalanche Photodiodes (APD). The spectrometer will consist of seven collimated arrays, each containing 14 APDs and covering 1 steradians. CATSAT also contains three other context instruments. The Directional Gamma Spectrometer is a NaI-PMT array which will provide burst triggering as well as spectra and directional information from > 200 keV observations. The Hard X-Ray spectrometer consists of CaF₂(Eu)-PMT detectors which are optimized in the cyclotron absorption energy band. The X-ray Albedo Polarimeter consists of nine collimated NaI-PMT detectors observing the earth reflected emission. Results from the XAP will be used to determine the burst direction and to place constraints on X-ray polarization. CATSAT was designed at three universities to be built with student help in two years for a cost of $3.5M.     

Debris flows in Glacier National Park, Montana: geomorphology and hazards

Debris flows are one of the many active slope-forming processes within Glacier National Park, Montana. Most debris flow landforms exhibit classic morphology with a distinct failure scarp, incised channel, channel levees, and toe deposits that often develop a lobate form. The Precambrian metasediments that dominate Glacier National Park's geology weather into angular clasts that range in size from platy gravels to boulders. Classic debris flows occur in areas where the topographic expression provides a debris source from cliff faces and an accumulation of regolith, often in the form of talus slopes. Many of these debris flows have long runout zones and can travel many hundreds of meters. Often they cross hiking trails or roads, including the main east–west highway, Going-to-the-Sun Road. Debris flows impacting the road have resulted in several near fatalities, and hikers have been forced to cross active debris flows to reach safe ground. The magnitude of debris flows varies between high magnitude channel incising events and low magnitude channel filling and/or reworking events. The frequency of debris flow events is irregular and appears to be controlled by the hydrology of triggering storms and antecedent moisture conditions, not by the debris supply. As a result, debris flow magnitude is not a function of frequency, but is more closely related to the characteristics of antecedent conditions and individual storms.     

The geography of campaign funding,campaign spending and voting at the New South Wales legislative assembly elections of 1984

The relationship between campaign fund raising, campaign expenditure and voter support levels for the two major parties, Labor and the Coalition, is explored by means of regression analysis. Results confirm the existence of significant relationships, in particular that, holding constant other influencing factors, the more a party raises and spends during a campaign, the more votes it wins.     

REAL TIME THREE DIMENSIONAL IMAGING

An account is given of the importance of photogrammetric techniques in industrial three dimensional problems and the way in which obtaining data in this environment differs from the more common applications. Possible system arrangements are discussed. The particular choice at Imperial College and the resulting system speed and accuracy are presented.     

ASIANS,PACIFIC ISLANDERS,AND ETHNOBURBS IN AUCKLAND,NEW ZEALAND

ABSTRACT. Recent work on Asian ethnic minority immigrants to cities in the Anglophone Pacific Rim argues that their settlement patterns do not conform to those of earlier migrant streams. Instead of concentrating in high‐density, low‐quality, inner‐city housing, these new residents are moving directly to suburban areas where they form much less intensive concentrations—ethnoburbs—than has been typical of other culturally distinct migrant groups. We evaluate this thesis for Asian migrants in the Auckland metropolitan area, whose numbers more than quadrupled between 1991 and 2006. Their residential pattern is compared with that of Pacific Islanders also resident there, providing supporting evidence for the ethnoburb hypothesis.     

Hard X-ray and low-energy gamma-ray spectrometers

Basic principles of operation and characteristics of scintillation and semi-conductor detectors used for solar hard X-ray and gamma-ray spectrometers are presented. Scintillation materials such as NaI offer high stopping power for incident gamma rays, modest energy resolution, and relatively simple operation. They are, to date, the most often used detector in solar gamma-ray spectroscopy. The scintillator BGO has higher stopping power than NaI, but poorer energy resolution. The primary advantage of semi-conductor materials such as Ge is their high-energy resolution. Monte-Carlo simulations of the response of NaI and Ge detectors to model solar flare inputs show the benefit of high resolution for studying spectral lines. No semi-conductor material besides Ge is currently available with adequate combined size and purity to make general-use hard X-ray and gamma-ray detectors for solar studies.