Санкт-Петербург, Политехническая ул., д. 29, Г.З., оф.234, общий отдел:  920-01-97, вакуумное оборудование: 920-71-97

MICROWAVE WEIGHER

Russian patent #1760458

The weigher is designed for contactless mass measurements of the multiple flying macroparticles. It uses the microwave methods (resonator or interferometric) based on the difference between the dielectric constants of substance and vacuum. Macroparticles should consist of electrically homogeneous substance.

The essence of the resonator method is the shift of the resonant frequency of a cavity due to a macroparticle flying through. In the case of interferometric method, a macroparticle flies through narrow apertures in the opposite sides of the wave guide.

Except mass measuring this system can be used to measure velocity, mass losses rate of the macroparticles, low vacuum or excess pressure of gases.

This system was developed to measure mass of accelerated solid hydrogen pellets used in the plasma physics. The specific unit was designed for frequency range of 9 GHz but this technique allows one to use another frequency range for better matching to macroparticle size.

The system was produced and installed on ASDEX-Upgrade, NIFS-stand.

The weigher can be shielded against a constant magnetic field up to 1 kGs.

Measured mass of macroparticle

1 - 10

mg

Macroparticle velocity

30 - 8000

m/s

Operation frequency

9

GHz

Accuracy of mass measurement

0,2

<15

mg

%

Permissible radial scattering

10

mm

Permissible scattering in certain direction

80

mm

Distance between sequential macroparticles

>30

mm

Range of measured pressure

0,1 - 5

bar

The system can be adapted to another ranges of macroparticle masses and velocities, for example: M = 0-,3 - 3 mg and V = 90 - 16000 m/s or M = 5 - 50 mg and V = 30 - 8000 m/s etc.