Multi-epoch Spitzer Space Telescope 24 µm data is utilized from the MIPSGAL and Taurus Legacy surveys to detect asteroids based on their relative motion .
These infrared detections are matched to known asteroids and rotationally averaged diameters and albedos are derived using the Near Earth Asteroid Model ( NEATM ) in conjunction with Monte Carlo simulations for 1835 asteroids ranging in size from 0.2 to 143.6 km .
A small subsample of these objects was also detected by IRAS or MSX and the single wavelength albedo and diameter fits derived from this data are within 5 % of the IRAS and/or MSX derived albedos and diameters demonstrating the robustness of our technique .
The mean geometric albedo of the small main belt asteroids in this sample is p _ { V } = 0.138 with a sample standard deviation of 0.105 .
The albedo distribution of this sample is far more diverse than the IRAS or MSX samples .
The cumulative size-frequency distribution of asteroids in the main belt at small diameters is directly derived .
Completeness limits of the optical and infrared surveys are discussed .