Commercial alpha counters are used in science and industry applications to screen materials for surface radon progeny contamination. In this paper, we characterize an XIA UltraLo-1800, ionization drift counter, study the response embedded charge polyethylene sample measurements. We show that modeling such effects is possible a Geant4-based simulation framework attempt derive corrections. This p...

In view of the fact that the radon progeny contribute the highest to the natural radiation dose to general populations, large scale and long-term measurements of radon and its progeny in the houses have been receiving considerable attention. Solid State Nuclear Track Detector (SSNTD) based systems, being the best suited for large scale passive monitoring, have been widely used for the radon gas...

Measurements of thoron (""Rn) have been performed in some 90 buildings during 1992 and 1993, as parts of two different investigations. The measurements were performed in order to form a basis for assessing the risk for high thoron levels indoors in Sweden. In the first study thoron progeny measurements were undertaken in 53 dwellings and 7 workplaces at 13 different locations in south and centr...

The airway dimensions for Caucasian males have been scaled by multiplying by factors 0.95 and 0.88 to give those for Chinese males and females, respectively. Employing the most recent data on physical and biological parameters, the radiation doses to the basal and secretory cells due to alpha particles from 218Po and 214Po, homogeneously distributed in the mucous layer, have been calculated. Th...

Radon gases released from the ground surface and building materials are the major sources of ionization in the indoor atmosphere. Radon will undergo radioactive decay in the atmosphere by emitting an alpha particle. The alpha and beta particles, and the gama rays from Rn, Rn and their decay products give up their energy by ionizing the molecules and aerosol particles in the atmosphere. Radon an...

We have previously shown that when adult marrow CD34+/HLA-DR- cells are cultured for 5 or 8 weeks in the presence of stroma-conditioned media with interleukin-3 (IL-3) and macrophage inflammatory protein-1 alpha (MIP-1 alpha), long-term culture-initiating cells (LTC-IC) are maintained but not expanded. However, if the same cultures are evaluated after 2 weeks, we show that LTC-IC expand 5.5- +/...

To analyze cell lineage in the pancreatic islets, we have irreversibly tagged all the progeny of cells through the activity of Cre recombinase. Adult glucagon alpha and insulin beta cells are shown to derive from cells that have never transcribed insulin or glucagon, respectively. Also, the beta-cell progenitors, but not alpha-cell progenitors, transcribe the pancreatic polypeptide (PP) gene. F...

Successive T-precursors isolated from adult mouse thymus were examined for their developmental potential, by transfer to irradiated Ly 5-disparate recipients. The earliest, "low CD4" precursors formed T, B, and dendritic cells (DC), but not myeloid cells, in accordance with earlier studies. Surprisingly, the next downstream CD4-8-3 44+25+ precursor population still formed DC as well as T cells ...

A computer programwas developed to calculate the light scattered from an assembly of alpha particle tracks in a PADC film. The tracks were randomly seeded on the film to simulate the irradiation by alpha particles emitted by the naturally occurring radon gas and its short-lived progeny. The ray-tracing method was applied to simulate light propagation through the tracks. The angular distribution...