Mass-spectrometer MTI-350T

The mass-spectrometer MTI-350T is intended for measuring the isotopic composition of uranium, plutonium and blended fuel in solid. Besides, the instrument can be used at making measurements for geology, metallurgy and other branches where the isotopic or chemical analysis of substances in solid is required.

Features:

thermionic double-band drum-type ion source for 11 samples;

accurate positioning of the sample under analysis;

ion multi-collector with adjusted position of collectors;

electronic part executed with application of the modern hardware components;

controller computer on the basis of the advanced reliability industrial computer;

specialized software performing control over the instrument and automatic measurement of isotopic composition.

Underlying the mass-spectrometer structure is a basic analytical part of МТИ-350Г as well as the unified blocks of the electronic part. The basic structure is supplemented by assemblies newly developed according to the solid analysis specificity – thermion source and nine-channel collector with automatic adjustment of the moving collectors position.

Mass-spectrometer can be produced in two makes – laboratory version intended for carrying out the isotopic analysis in common laboratory conditions, and three-zone version intended for isotopic analysis of uranium, plutonium and blended fuel, as well as other highly active samples with observance of the requirements of zonal personnel protection system as per OTT 08042462. In the zonal version the analytical part is located in the repair zone which the personnel attend for a short time, in the course of works with active substances. Besides, in the zonal version the ion source chamber is equipped with the standard protective box providing the personnel protection during the works with active samples. The electronic units with controls, the master computer, and the operator’s table are located in the operator’s zone where the personnel are constantly present making measurements and checking the instrument operation.

Characteristics of MTI-350T

Resolution capability – not less than 800;

Instability at the peak slope for 20 minutes – not more than 2•10^-5;

Upper boundary of mass range – not less than 300 amu;

Isotopic response threshold – not more than 1•10^-5;

Nonplanarity of the top – not more than 2•10^-4;

Uranium and plutonium samples use factor – not less than 0.2%;

Number of positions in the ion source drum – 11;

Time for making 10 analysis in automatic mode – not more than 8 hours;

Number of channels for ion current measurement in ion collector – 10;

Full average service life of the mass-spectrometer – not less than 10 years

Limit of the permissible mean-square deviation of relative error random component, %:

for ²³⁵U content
in the range of (0,5-1,0)%	0,04
²³⁴U and ²³⁶U content
in the range of (0,0005 – 0,06)%	5,0
for ²³⁹Pu content
in the range of (60 to 90) %	0,05
for ²⁴¹Pu content
in the range of (1 to5) %	0,1

The mass-spectrometer МТИ-350Т is registered in the State Register of Measuring Instruments under No. 38604-08 and is admitted for application in the Russian Federation (Pattern Approval Certificate of Measuring Instruments RU.C.31.005.A No. 32681). For verification, calibration, graduation of the mass-spectrometer МТИ-350Т as a measuring instrument and for metrological certification of the measuring methods with application of МТИ-350Т there was developed a Certified Reference Material of plutonium isotopic composition ГСО 8843-2006.

Additional equipment:

For simplification and acceleration of works on samples preparation and other routine works necessary at operation, the mass-spectrometer МТИ-350Т was completed with the additional equipment:

device for making evaporator and ionizer bands;

device for shaping and welding of bands;

stand for degasification and preliminary curing of bands;

complete set for application of samples;

device for installation and removal of ion source drum;

hermetical container for transportation of ion source drum.

Band heating unit is intended for preliminary curing of bands and provides for the manually adjustable heating current up to 5A separately by each of two channels with control by pointer indicator. Installed on each channel are 11 ionizers. A possibility of current switching-off simultaneously in both channels by means of a timer is provided for in the unit. Selection is performed by the rotary switch. Switching-off time – 30; 45; 60; 120 minutes.

Complete set for application of samples. Prior to the analysis it is necessary to apply the substance under test to the cathodes which will be used as evaporators. To this end, the use is made of a small unit allowing simultaneous installation of up to 11 ionizers. Each ionizer is installed in turns to the application area and a sample is applied by means of a single-channel dosing unit with variable capacity of 0.5 to 10 µl.