Download 21209885F

System Description
Hardware
Nephelometer
Assembly
The nephelometer assembly uses an 880 nanometer incident light source
and hybrid silicon photodetector to measure the intensity of scattered light
in the presence of aerosol. This assembly houses a nephelometer,
temperature sensor, relative humidity sensor, and PCB interface.
Primary
Measurement Head
The primary measurement head uses a beta source and proportional
alpha/beta detector to measure the attenuation of beta particles by sampled
aerosol across a glass fiber filter and to discriminate against any naturally
occurring beta interferences from the daughter nuclides of alpha decay
products.
Detector Amplifier
This cylindrical tube houses a printed circuit board, provides power to the
proportional detector and amplifies the beta and alpha counts prior to
being sent to the 5030i measurement interface board.
Cam Photo Interrupt
Board
This small printed circuit board includes a photo-interrupter to detect the
closed position of the measurement head. This is connected to a motor
assembly used to open and close the measurement head.
Counter Wheel Interrupt
Board Assembly
8-4
This small printed circuit board is mounted onto a chopper wheel that
measures the amount of filter tape advanced during a filter tape change.
Proportional Valve
The proportional valve is a proportional solenoid valve that is used as a
means of flow control. In response to the measured flow across a subsonic
orifice, the proportional valve will either partially open or close to make a
flow adjustment in real-time.
Cam Motor
This motor is used to drive the cam to rotate. By rotating the cam, the
measurement head lever arm is raised and lowered for opening and closing
the measurement head during a filter tape change.
Tape Motor
After the measurement head is opened, this motor is used to advance the
filter tape a fixed amount prior to initiating another beta attenuation event
on a fixed sample spot.
Model 5030i SHARP Instruction Manual
Thermo Fisher Scientific