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.
| Design | LTEC |
|---|---|
| Heater | Ta wire, PBN insulator Regular/hot lip/dual filament options |
| Flange Sizes | 2.75” (DN40CF), 4.5” (DN63CF), Larger sizes on request |
| Temperature range | 75-1100 °C (max temp may be limited due to crucible material choice) |
| Outgassing temperature | 1200 °C |
| Bakeout temperature | 250 °C |
| Thermocouple | Type K (Type C on request) |
| UHV dimensions | See table below |
| Crucible | PBN standard, other options available |
| Cables | 200 °C bakeable, 20 ft |
| Option: Cooling | Integrated or separate water-cooling shroud Water requirements: 5-15 °C, 1 l/min flow rate |
| Option: shutter | Integrated rotary Ta shutter blade, manual or pneumatic |
| Part Number | CF Flange Size | Integrated water cooling? | Can integrate shutter? | Crucible volume (cm3) | Filament options | Vacuum dimensionsODxLmin (mm) |
|---|---|---|---|---|---|---|
| LTEC-275S-1 | 40 | Yes | 1.5 | R | 35×175 | |
| LTEC-275WCS-1 | 40 | Yes | Yes | 1.5 | R | 35×175 |
| LTEC-275S-10 | 40 | Yes | 10 | R, HL, D | 35×200 | |
| LTEC-275WCS-10 | 40 | Yes | Yes | 10 | R, HL, D | 35×200 |
| LTEC-275S-25 | 40 | Yes | 25 | R, HL, D | 38×200 | |
| LTEC-275S-35 | 40 | Yes | 35 | R, HL, D | 38×225 | |
| LTEC-275-40 | 40 | 40 | R, HL, D | 38×225 | ||
| LTEC-275-60 | 40 | 60 | R, HL, D | 38×225 | ||
| LTEC-450S-35 | 63 | Yes | 35 | R, HL, D | 57×200 | |
| LTEC-450WCS-35 | 63 | Yes | Yes | 35 | R, HL, D | 57×200 |
| LTEC-450S-60 | 63 | Yes | 60 | R, HL, D | 57×200 | |
| LTEC-450WCS-60 | 63 | Yes | Yes | 60 | R, HL, D | 57×200 |
More Effusion Cells
Low Temperature Effusion Cell (LTEC)
Medium Temperature Effusion Cell (MTEC)
High Temperature Effusion Cell (HTEC)
