3BG0 pages

New Product of XHV gauge head: 3BG-03
Measurable as low as 10-12Pa
・ Reduction of Soft X-ray & ESD by Bent Belt-Beam method
・ Full-closed cylindrical cage-grid with an axial-slit
・ Low outgassing hot-cathode gauge by using 0.2%BeCu alloy body
What is Bent Belt-Beam (BBB) Gauge ?

DN40 CF
Top view of the 3BG-03, without the cover on the
deflector and collector. The flanged mounting
surface of the deflector can be seen in the picture,
with its 3 mounting holes. Within the functional
volume of the gauge, the deflector is an open
array of bars and slots.
Grid
( Pt clad Mo wire)

Filament
( Ir-Y2O3 )
Collector
( Au-SUS)

3BG-03 is a commercially extreme-high vacuum
hot-cathode ionization gauge head that can measure
pressures as low as 5.4 × 10–12 Pa, by reducing the
limits imposed by soft x-rays, electron-stimulated
desorption (ESD), and outgassing. The gauge
construction includes a cylindrical grid, which is
closed at both ends; ions are drawn from the grid
through a long, axial slit made in the cylindrical
surface. Thus, the ion beam that emerges forms a
"belt". This belt-like ion beam is guided on a curved
path by a cylindrical sector deflector and terminates
on a plate collector arranged after a beam trajectory
rotation of 240°. These elements are embedded in a
solid cylinder of 0.2% BeCu alloy, which has a low
emissivity (radiation factor) and high thermal
conductivity. As a result, the effects of heat radiation
and outgassing (caused by the hot-cathode filament)
and soft x-ray photoemission (the grid is the soft xray source) are reduced in the deflector/collector
region. This electrode arrangement can also greatly
decrease the flux of soft x-rays and ESD in the
direction of the belt ion beam because it sets to 90°
the angle between the extracted gas-phase ion beam
and the maximum flux of soft x-rays and ESD. In
addition, it achieves an extremely low pressure
measurement limit by minimizing loss in the ion
transport, and because the collector is well hidden,
being located after the large deflection of the ion
beam.
Operational Parameters & data

Gauge Body
( 0.2%BeCu alloy)

Bent Belt-Beam

Electron energy = 120eV (standard)
Filament potential = 100 V (standard)
Filament Power = 2V×1.5A at 1.6mA
Deflector bias = 155 V (between 1~4mA)
Degas = Electron Bombardment (450V×10~45mA)
Bakeout Temperature = 280℃max
Size = φ70mm×58mm
Weight = 1.1 kg
Connector = BNC & 8pin Burndy-J
Sensitivity factor = 5~8×10-2 Pa-1 (at 1~ 4mA)
X-ray limit < 5×10-12 Pa
3BG-03 can operate with Oerlikon Leybold IM540

Design, manufacturing and consulting of vacuum gauge and RGA

VacLab Inc.

SOHO103, 2-10-2 Matsushiro-Tsukuba
Ibaraki 305-0035 Japan
TEL:+81-29-861-8833
FAX:+81-29-861-8859
E-mail: info@vaclab.co.jp, http//www.vaclab.co.jp