The graphite blackbody BB22p combines a reasonable price and excellent performance, which has been attained by using modern hi-tech materials to build the radiator and thermal insulation elements and applying some ingenious design features. BB22p is intended for accurate and reliable measurements of spectral radiance and spectral irradiance in the wavelength range starting from 250 nm, and also for temperature measurements.

Figure above shows a cross-section of the BB22p blackbody. Its graphite coaxial radiator inside the chamber is fixed on water-cooled copper electric current leads by two graphite disks. The front disk holds a fixed external radiator tube with a thermally insulated shell made of a fibrous graphite material with high thermal stability and good thermal insulation properties. The rear disk is flexibly connected with a graphite sleeve used to pick off the electric current, with the rear end of the radiator internal tube resting on the end face of this sleeve through a pyrographite ring.

The front end of the radiator’s internal tube is connected with the front end of the external tube through another pyrographite ring. Structural stiffness and reliable electric contact of the two graphite tubes of the coaxial assembly are ensured by a special clamp.

The pyrographite support rings on both sides of the radiator’s internal tube allowed a more uniform temperature field to be attained along the cavity cylindrical surface because pyrographite has substantially lower thermal conductivity as compared with graphite and, therefore, tends to reduce the heat outflow from the ends of the internal tube to colder graphite components.
The radiating cavity is formed by the cylindrical surface of the tube and the conic surface of the bottom inside the tube.

To equalize the temperatures at the bottom and on the sidewall surface of the cavity, the cross-section of the rear part of the internal tube is reduced to ensure additional heating of the bottom to compensate for radiation losses.

In addition, flat pyrographite thermal shields are placed between the backside of the cavity bottom and the rear pyrographite support ring to reduce the radiation losses from the auxiliary cavity.
The geometric parameters of the radiating cavity are as follows: its depth is 130 mm, inner diameter 22 mm, aperture diameter 14 mm, and the cone’s vertex angle 140°. Blackbody is placed into a water-cooled chamber and can operate both in vacuum and in inert gas atmosphere with no output window.
The parameters of the BB22p blackbody have been thoroughly studied by now It is employed by major metrological centers and considered one of the best high-temperature blackbodies currently available for metrological applications.
The BB22p source is used in NIST (USA), PTB (Germany), NPL (Great Britain) and VNIIOFI (Russia) for spectral radiance and spectral irradiance precision measurements.

Delivery Set

1. Stainless steel water cooled housing
2.Radiator assembly
3.One spare set of replaceable parts
4.Argon purge supply/safety interlock systems with flow meter (low pressure input)
5.Cooling plant water supply/safety interlock systems with flow meter
6.Precision aperture with water-cooled holder
7.Temperature stabilized water circulator for aperture holder andoptical feedback system
8.Vacuum vane pump with pressure gauge and accessories
9.User Manual and Protocols of Tests

System integration and personnel training, including
10 days on-site visit of Vega International specialist.
12 months warranty parts and labor.


References

1) V.I.Sapritsky, B.B.Khlevnoy, V.B.Khromchenko, B.E.Lisiansky, S.N.Mekhontsev, U.A.Melenevsky, S.P.Morozova, A.V.Prokhorov, L.N.Samoilov, V.I.Shapoval, K.A.Sudarev, M.F.Zelener. Precision blackbody sources for radiometric standards -Applied Optics, 1997, v. 36, pp. 5403-5408
2) Sapritsky V.I., Khlevnoy B.B., Khromchenko V.B., Lisiansky B.E., Mekhontsev S.N., Morozova S.P, Shapoval V.I., Samoilov L.N., Zelener M.F., Prokhorov A.V. Precision blackbody sources for radiometry and radiation thermometry – TEMPBEIJING ’97. Proc. of the Int. Conf. on the Temperature and Thermal Measurement. Beijing, China, October 6-10, 1997, pp. 141-146
3) Sapritsky V.I., Khlevnoy B.B., Khromchenko V.B., Lisiansky B.E., Mekhontsev S.N., Morozova S.P., Shapoval V.I., Samoilov L.N., Prokhorov A.V., Zelener M.F. Precision blackbody sources for thermometry and radiometry. – 6 th International Symposium on Temperature and Thermal Measurement in Industry and Science (TEMPMEKO’96). Torino, Italy, 10-12, September, 1996, pp. 321-326
4) White M., Fox N.P., Ralph V.E., Harrison N.J. The Characterisation of a High Temperature Blackbody as the Basis for the NPL Spectral Radiance Scale -Metrologia, 1995/1996, v. 32, No. 6, pp. 431-434
5) Sperfeld P., Raatz K.-H., Nawo B., M?ller W., Metzdorf J. Spectral Irradiance Scale Based on Radiometric Black-Body Temperature Measurements - Metrologia, 1995/1996, v. 32, No. 6, p. 435-439