Patent ID: 9157871
Filing Date: 2015-10-13
Classification: G01N

Abstract:
1. A particulate mass measurement apparatus of a beta mass attenuation type comprising: a nozzle having an ambient airflow chamber with an axial ambient airflow pathway therein, the airflow chamber having a neck with an ambient air inlet and curved surfaces in the airflow direction extending from the neck; a beta radiation source housing disposed within the ambient air flow chamber and a beta radiation source disposed within the beta source housing, the beta source housing having a curved surface in the airflow direction splitting the axial ambient airflow pathway; a sheath air plenum in fluid communication with the ambient airflow chamber and a radial sheath airflow pathway extending from the plenum and merging with the ambient airflow pathway, wherein radial sheath airflow from within the radial sheath airflow pathway is substantially particle free air that merges with the ambient airflow between curved surfaces of the airflow chamber and the beta source housing guiding the ambient airflow thereby deflecting ambient air including ambient air particulate matter from the curved chamber wall surfaces; a filter tape disposed beneath the beta source; a beta radiation detector disposed beneath the filter tape; and an outlet.