LTEC

Low Temperature Effusion Cell

VolkVac Instruments’ LTEC is optimized for evaporation of moderately high vapor pressure material. Common examples are alkali and alkaline earth metals as well as topological material like Cd, Te, Bi, Pb and other.

The design of the Ta wire heater and radiation shielding inside the LTEC is optimized for stable temperature control (±0.1 °C, depending on PID controller used) in the 75-1100 C range. The filament can come in regular, hot lip and dual filament winding configurations.

The most common crucible material is PBN due to its chemical inertness, low vapor pressure and clean outgassing in UHV as well as high thermal shock resistance. However, other crucible materials may be appropriate based on the required application. Please consult VolkVac for recommendations.
Majority of application do well with cylindrical crucible geometry (~1° wall taper) but conical crucibles (~10° wall taper) are available on request. Please consult VolkVac for recommendations.

LTECs can be supplied with an integrated water-cooling shroud, or as bare evaporators if customer already has a cooling shroud in place. Most evaporators can also be fitted with an integrated rotatable shutter, with manual or compressed air actuation. See table below for options.

To deal with loading highly air-sensitive materials (such as alkali metals) into the chamber, a convenient solution is to use an evaporator retraction unit (ERU) along with the effusion cell such as LTEC-275WCS-10. Ask VolkVac for more information.

LTEC - Volkvac Instruments | UHV Design
DesignLTEC
HeaterTa wire, PBN insulator
Regular/hot lip/dual filament options
Flange Sizes2.75” (DN40CF), 4.5” (DN63CF), Larger sizes on request
Temperature range75-1100 °C (max temp may be limited due to crucible material choice)
Outgassing temperature1200 °C
Bakeout temperature250 °C
ThermocoupleType K (Type C on request)
UHV dimensionsSee table below
CruciblePBN standard, other options available
Cables200 °C bakeable, 20 ft
Option: CoolingIntegrated or separate water-cooling shroud
Water requirements: 5-15 °C, 1 l/min flow rate
Option: shutterIntegrated rotary Ta shutter blade, manual or pneumatic
Part NumberCF Flange SizeIntegrated water cooling?Can integrate shutter?Crucible volume (cm3)Filament optionsVacuum dimensionsODxLmin (mm)
LTEC-275S-140Yes1.5R35×175
LTEC-275WCS-140YesYes1.5R35×175
LTEC-275S-1040Yes10R, HL, D35×200
LTEC-275WCS-1040YesYes10R, HL, D35×200
LTEC-275S-2540Yes25R, HL, D38×200
LTEC-275S-3540Yes35R, HL, D38×225
LTEC-275-404040R, HL, D38×225
LTEC-275-604060R, HL, D38×225
LTEC-450S-3563Yes35R, HL, D57×200
LTEC-450WCS-3563YesYes35R, HL, D57×200
LTEC-450S-6063Yes60R, HL, D57×200
LTEC-450WCS-6063YesYes60R, HL, D57×200
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More Effusion Cells

Low Temperature Effusion Cell (LTEC)

LTEC - Volkvac Instruments | UHV Design

Medium Temperature Effusion Cell (MTEC)

MTEC - Volkvac Instruments | UHV Design

High Temperature Effusion Cell (HTEC)

HTEC - Volkvac Instruments | UHV Design

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