Advantages The use of an electron beam enables not only observation of the submicron world
(TEM’s SEM’s and X-ray microanalysers) but also processing with submicron precision
(electron beam lithography systems). The optimum cathode material for use in these instruments would
possess the following properties:
- Low potential barrier (work function)
- High melting point and stability at high temperatures
- Low vapor pressure so as to reduce evaporation loss
- Chemical stability
The relative drawbacks of tungsten cathodes are a work function of 4.7eV, insufficient beam current,
and a short service life. LaB6 has a work function of 2.66eV thus more easily emitting
electrons and is a relatively stable material, so it has been increasingly used as a material for
cathodes instead of tungsten. Using LaB6 cathodes with TEMs and SEMs,
even with the electron beam narrowed down, it is possible to obtain enough beam current to achieve
better resolution and clear micrographs with less noise. The principle advantage, however, is that
LaB6 can be used in a stable condition for a much longer time. Denka manufactures the purest,
highest quality LaB6 crystals for use in their cathode tips.
Applications are:
- SEM
- TEM
- X-ray Beam Analysis (EPMA)
- Electron Beam Lithography
Benefits
-
High Brightness: A LaB6 beam is 10 times brighter than tungsten, has superior
resolution, and features a wide range of acceleration voltages. It provides sharp, clear pictures,
down to the smallest detail. The initial brightness of a Denka Model 3 cathode (1 x 106A/cm2.Str) is
substantially better than that of competing, mini-vogel type cathodes (typically 5 x 105A/cm2.Str).
-
Long Life: Heat and vacuum are the final determinants of any cathode tip’s life,
but at 1550°C and a vacuum of 10-7 Torr, a service life of about 500 hours can be expected.
-
Stability: Thanks to its simple and durable construction, every Denka Model 3 LaB6
Cathode offers a stability of better than 3% per hour at 1550°C.
-
Interchangeability: Denka Model 3 LaB6 cathodes are designed as direct replacements
for tungsten filaments when a vacuum in the 10-7 range is provided.
|
Comparison of Tip Configurations Available with Denka M-3 LaB6 AEI style Cathodes |
|
Flat Tip |
Standard (Round) Tip |
Sharp Tip |
|
90° or 60° cone angle 20/40/60/100µm flat tip radius |
90° cone angle 15µm tip radius |
60° cone angle 5µm and 10µm tip radius |
Brightness |
About 5 times that of tungsten
2-5 x 105 A/cm2 • Str |
About 10 times that of Tungsten
1 x 106 A/cm2 • Str |
Twice as bright as standard tips
2 x 106 A/cm2 • Str |
Saturation |
Mono spot at about 1,400°C |
Mono spot at about 1,500°C |
Almost the same as standard tips |
Crossover |
Large (11-13µm) |
Small (7-10µm) |
Small (7-10µm) |
Angular Distribution |
Broad
3.3-4.2 x 10-2rad |
Sharp
1.6 x 10-2rad |
Sharp
1.6 x 10-2rad |
Used Temperature |
Low Temperature |
High Temperature |
High Temperature |
Lifetime |
Long life (usable at low temperatures, and crystallized end changes slowly) |
Long life; shorter than flat tips |
Short |
Operation |
Easy (thanks to its large spot size and broad adjusting range) |
Not so difficult |
Difficult (the point adjustment needed) |
Stability |
High (invulnerable to thermal expansion or vibration) |
High |
Middle (vulnerable to thermal expansion or vibration, adjustment is sometimes necessary) |
Technology Needed |
Ordinary |
High |
Very High |
|
 |
Denka M-3 LaB6 Cathode for JEOL Instruments
(compatible with K-type filament base) |
Prod #
| Description
| Unit
| Price
| Order / Quote
|
1450
| Denka M-3 LaB6, Filament, LKS/90-15, standard tip
| each
| $1149.50
|
|
|
 |
Denka M-3 LaB6 Cathode for FEI, Philips Instruments (Except XL-30) |
Prod #
| Description
| Unit
| Price
| Order / Quote
|
1451
| Denka M-3 LaB6, Filament, PH2/90-15, standard tip
| each
| $1215.00
|
|
|
 |
Denka M-3 LaB6 Cathode for AMRAY Instruments
(except 1200 Series) |
Prod #
| Description
| Unit
| Price
| Order / Quote
|
1452
| Denka M-3 LaB6 Filament, AM/90-15, standard tip
| each
| $1220.00
|
|
|
 |
Denka M-3 LaB6 Cathode AEI base for Cambridge (except S2A and S4-10), Camscan, Electroscan,
Leica, LEO and Zeiss (EVO®) Instruments
|
Prod #
| Description
| Unit
| Price
| Order / Quote
|
1453
| Denka M-3 LaB6 Filament, CA/90-15, standard tip
| each
| $1042.00
|
|
|
 |
Denka M-3 LaB6 Cathode for Hitachi Instruments |
Prod #
| Description
| Unit
| Price
| Order / Quote
|
1454
| Denka M-3 LaB6 Filament, H2/90-15, standard tip
| each
| $1063.30
|
|
|
 |
Denka M-3 LaB6 Cathode for ZEISS/LEO TEM, Zeiss DSM SEMs, or Tescan SEMs |
Prod #
| Description
| Unit
| Price
| Order / Quote
|
1449
| Denka M-3 LaB6, Filament, Z2/90-15, standard tip
| each
| $1042.00
|
|
|
Prod #
| Description
| Unit
| Price
| Order / Quote
|
1455
| Denka LaB6 Filament, AM/60-5, Sharp Tip
| each
| $1238.50
|
|
1456
| Denka LaB6 Filament, AM/60-10, Sharp Tip
| each
| 1208.00
|
|
1457
| Denka LaB6 Filament, AM/60-20, Flat Tip
| each
| 1299.00
|
|
1458
| Denka LaB6 Filament, AM/60-40, Flat Tip
| each
| 1424.00
|
|
1459
| Denka LaB6 Filament, AM/60-60, Flat Tip
| each
| 1548.50
|
|
1460
| Denka LaB6 Filament, AM/60-100, Flat Tip
| each
| 1798.00
|
|
1461
| Denka LaB6 Filament, AM/90-20, Flat Tip
| each
| 1121.00
|
|
1462
| Denka LaB6 Filament, AM/90-40, Flat Tip
| each
| 1245.50
|
|
1463
| Denka LaB6 Filament, AM/90-60, Flat Tip
| each
| 1370.00
|
|
1464
| Denka LaB6 Filament, AM/90-100, Flat Tip
| each
| 1619.00
|
|
Numbers represent: Cone Angle - Tip Radius in µm
|
Prod #
| Description
| Unit
| Price
| Order / Quote
|
1465
| Denka LaB6 Filament, CA/60-5, Sharp Tip
| each
| $1239.00
|
|
1466
| Denka LaB6 Filament, CA/60-10, Sharp Tip
| each
| 1208.00
|
|
1467
| Denka LaB6 Filament, CA/60-20, Flat Tip
| each
| 1299.00
|
|
1468
| Denka LaB6 Filament, CA/60-40, Flat Tip
| each
| 1424.00
|
|
1469
| Denka LaB6 Filament, CA/60-60, Flat Tip
| each
| 1548.50
|
|
1470
| Denka LaB6 Filament, CA/60-100, Flat Tip
| each
| 1798.00
|
|
1471
| Denka LaB6 Filament, CA/90-20, Flat Tip
| each
| 1121.00
|
|
1472
| Denka LaB6 Filament, CA/90-40, Flat Tip
| each
| 1245.50
|
|
1473
| Denka LaB6 Filament, CA/90-60, Flat Tip
| each
| 1370.00
|
|
1474
| Denka LaB6 Filament, CA/90-100, Flat Tip
| each
| 1619.00
|
|
Numbers represent: Cone Angle - Tip Radius in µm
|
Prod #
| Description
| Unit
| Price
| Order / Quote
|
1475
| Denka LaB6 Filament, H2/60-5, Sharp Tip
| each
| $1239.00
|
|
1476
| Denka LaB6 Filament, H2/60-10, Sharp Tip
| each
| 1208.00
|
|
1477
| Denka LaB6 Filament, H2/60-20, Flat Tip
| each
| 1299.00
|
|
1478
| Denka LaB6 Filament, H2/60-40, Flat Tip
| each
| 1424.00
|
|
1479
| Denka LaB6 Filament, H2/60-60, Flat Tip
| each
| 1548.50
|
|
1480
| Denka LaB6 Filament, H2/60-100, Flat Tip
| each
| 1798.00
|
|
1481
| Denka LaB6 Filament, H2/90-20, Flat Tip
| each
| 1121.00
|
|
1482
| Denka LaB6 Filament, H2/90-40, Flat Tip
| each
| 1245.50
|
|
1483
| Denka LaB6 Filament, H2/90-60, Flat Tip
| each
| 1370.00
|
|
1484
| Denka LaB6 Filament, H2/90-100, Flat Tip
| each
| 1619.00
|
|
Numbers represent: Cone Angle - Tip Radius in µm
|
Prod #
| Description
| Unit
| Price
| Order / Quote
|
1507
| Denka LaB6 Filament, LKS/60-20, Flat Tip
| each
| $1299.00
|
|
1508
| Denka LaB6 Filament, LKS/60-40, Flat Tip
| each
| 1424.00
|
|
1509
| Denka LaB6 Filament, LKS/60-60, Flat Tip
| each
| 1548.50
|
|
1510
| Denka LaB6 Filament, LKS/60-100, Flat Tip
| each
| 1798.00
|
|
1511
| Denka LaB6 Filament, LKS/90-20, Flat Tip
| each
| 1121.00
|
|
1512
| Denka LaB6 Filament, LKS/90-40v, Flat Tip
| each
| 1245.50
|
|
1513
| Denka LaB6 Filament, LKS/90-60, Flat Tip
| each
| 1370.00
|
|
1514
| Denka LaB6 Filament, LKS/90-100, Flat Tip
| each
| 1619.00
|
|
1515
| Denka LaB6 Filament, LKSH60, 10µm Sharp Tip, TEM only
| each
| 1232.70
|
|
1516
| Denka LaB6 Filament, LKSH60S, 5µm Sharp Tip, TEM only
| each
| 1264.50
|
|
Numbers represent: Cone Angle - Tip Radius in µm
|
Prod #
| Description
| Unit
| Price
| Order / Quote
|
1517
| Denka LaB6 Filament, PH2/60-5, Sharp Tip
| each
| $1239.00
|
|
1518
| Denka LaB6 Filament, PH2/60-10, Sharp Tip
| each
| 1208.00
|
|
1519
| Denka LaB6 Filament, PH2/60-20, Flat Tip
| each
| 1299.00
|
|
1520
| Denka LaB6 Filament, PH2/60-40, Flat Tip
| each
| 1424.00
|
|
1521
| Denka LaB6 Filament, PH2/60-60, Flat Tip
| each
| 1548.50
|
|
1522
| Denka LaB6 Filament, PH2/60-100, Flat Tip
| each
| 1798.00
|
|
1523
| Denka LaB6 Filament, PH2/90-20, Flat Tip
| each
| 1121.00
|
|
1524
| Denka LaB6 Filament, PH2/90-40, Flat Tip
| each
| 1245.50
|
|
1525
| Denka LaB6 Filament, PH2/90-60, Flat Tip
| each
| 1485.00
|
|
1526
| Denka LaB6 Filament, PH2/90-100, Flat Tip
| each
| 1619.00
|
|
Numbers represent: Cone Angle - Tip Radius in µm
|