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LIGHT-TIGHTNESS Foils of opaque materials (B, C, Ge, Si
have low opacity) over 2,000 angstroms in
thickness are guaranteed to have a light attenuation of 105
(optical
density 5.0) or greater. Because most foils are made by thin film processes,
these can only be made entirely free of pinholes by using special processes. Many of the thicker
foils are rolled and are light-tight. Typical foil has a light attenuation of 105
to
107 and we are committed to making foil with sufficient
light-tightness to meet any experimental requirement. On request, the
light leakage
of foil can be measured and reported to a sensitivity of 1 part in 109
(O.D. 9). Foils sold as vacuum tight have no He leaks larger than 1x10-7
std cm2/sec.
MECHANICAL STRENGTH We make no claims covering the ability
of these foils as windows to support
atmospheric pressure. This depends on many factors. We
will provide best-effort guidance upon request. Foils as thin as 0.1 micron are
used as windows between 10-5 and
10-9 torr vacuums. Foils
used as atmosphere to vacuum windows require exceptionally carefully designed
mounts. Even though a foil has no leaks, it may not be strong enough to support
1 atm of pressure over a large aperture. Lebow Company can supply mounted and
tested vacuum windows.
MOUNTING All foils are quoted mounted on suitable rings
(see MOUNTING rings in section 7, PART
NUMBERS, for Lebow standard ring specifications) with vacuum-compatible
adhesives or epoxies. No adhesive of any kind is used on foils under 0.1 micron
thick. A range of vacuum compatible adhesives and epoxies, as well as
adhesive-free UHV mounts are available to meet special needs. The engineers at
Lebow Company will gladly assist you in designing suitable foil mounts for your
application.
BACK TO TOP
SUPPORTS All foils are available
supported for additional
strength but supports are optional (all foils are made unsupported except for Mg,
Pb, Zn and fluorides) even for foil as thin as 20nm.
Standard
supports are mesh and/or Parylene N. Parylene
C & D and other plastics,
Polycarbonate (Lexan), PET (Mylar®
), PTFE (Teflon®
) and Polyimide (Kapton*), are also stocked in a wide range of thicknesses.
|
Support-Mesh
|
Pitch |
Space |
Bar |
Transmission |
Material |
|
Standard 0.36mm |
70 lpi* |
340µ |
18µ |
86% |
5µ Ni,
Electroformed |
|
|
|
|
|
|
|
Other Stock |
Mesh |
|
|
|
|
|
33µ |
750 lpi* |
25µ |
10µ |
55% |
5µ Ni,
Electroformed |
|
0.13mm |
200 lpi* |
112µ |
14µ |
78% |
5µ Ni,
Electroformed |
|
0.36mm |
70
lpi* |
344µ |
19µ |
86% |
5µ Cu,
Electroformed |
|
0.63mm |
40 lpi* |
0.60mm
|
0.03mm
|
94% |
25µ Stainless,
Etched |
|
1.27mm |
20 lpi* |
1.18mm
|
0.09mm
|
86% |
5µ Ni, Electroformed |
|
1.6mm |
16 lpi* |
1.56mm
|
0.04mm
|
88% |
37µ Stainless,
Etched |
|
2.5mm |
10 lpi* |
2.37mm |
0.17mm |
87% |
5µ Ni,
Electroformed |
*lines per inch
| Standard Ni mesh on L1.0 ring |
10 lpi Ni mesh on L1.0 ring |
High attenuation mesh- Wavelength independent
attenuation for
high flux applications
Mesh
| Transmission |
Pitch |
Hole |
Material |
|
1.4% |
0.56mm |
45 lpi |
|
0.18mm |
|
2 layers of 12% transmission |
|
12% |
0.56mm |
45 lpi |
|
0.18mm |
|
0.2mm 316 Stainless Steel
|
|
25% |
0.394mm |
64
lpi |
|
0.23mm |
|
0.2mm 316 Stainless Steel
|
|
50% |
0.73mm |
34 lpi |
|
Space 0.53mm
Bar 0.2mm |
|
0.2mm Expanded 304 Stainless Steel
|
Transmission is
nominal. Actual transmission will be labeled.
BACK TO TOP
Support-Parylene
N: (-C8H
8-), density 1.1)
| Stock Thicknesses |
0.1µ |
1.35µ |
4.0µ |
13.5µ |
|
0.2µ |
1.5µ |
5.0µ |
15.0µ |
|
0.5µ |
2.0µ |
6.0µ |
|
|
0.75µ |
2.5µ |
7.5µ |
|
|
1.0µ |
3.0µ |
10.0µ |
|
| Lebow Company is capable of making
very large Parylene N filters. The pictured 1.0 micron
Parylene N filter is 150mm in diameter. |
 |
TENSIONED FOILS
 |
Occasional experiments must focus
on the entire foil area, reflect a beam off the foil, or involve
ultrafast events over the entire foil area. These experiments
will benefit from tensioned flat foil. Tensioned foil of
most materials over 0.5µ thick can be made. This foil is
significantly more costly and requires epoxy mounting on special
rings |
|
PURITY The purest practical material
is used in all foil and the purity for total metal impurities
is indicated. Detailed material pedigrees and lot or individual foil analysis
are available at a nominal fee.
THICKNESS TOLERANCES ±10% standard; closer tolerances are
available upon request. We can supply
exact lot or individual foil measurement of the mechanical thickness,
weight/unit area or the apparent thickness by alpha energy loss as required for
a nominal fee.
Typical maximum surface non-uniformity is
1%/cm.
PART NUMBERS Our part numbers are descriptive, therefore
long, allowing an accurate identification of the required foil assembly.
Example:
0.5 Ti - P1K
- L1.34
(thickness) (material) (support) (mounting/size)
THICKNESS in microns (0.5)
1 micron (µ)
= 0.001mm = 1,000nm = 10,000 Angstrom (Å).
0.001 in.= 25.4
microns
MATERIAL indicated by chemical symbol for the element
(Ti).
SUPPORT
| 0 |
- |
Unsupported |
| P |
- |
Parylene-N
supported, 0.1µ
(P1K) |
| M |
- |
Nickel mesh, 5 microns
thick, 86% transmission, 36 micron pitch (70 |
|
|
lines/inch). Cu mesh and other mesh pitches are
available from stock. |
|
BACK TO TOP
|
MOUNTING/SIZE, specifies the mounting ring (L1.34, Lebow 1.34cm I.D.) and foil
size. Foils are mounted to cover only the unsupported area only and needed
margin for adhesive on Lebow rings, customer designed rings, or customer
supplied rings. Lebow is able to fabricate rings to customer drawings and regularly supplies complete foil assemblies for inclusion
in instruments. |
L- LEBOW STANDARD machined rings with beveled edge hole, 304
stainless steel, without mounting holes.
|
Inside Diameter |
Outside Diameter |
Thickness |
|
L0.5 |
5.0mm |
17.0mm |
1.5mm |
|
L1.0 |
10.0 |
17.0 |
1.5 |
|
L1.34 |
13.4 |
22.3 |
1.7 |
|
L1.5 |
15.0 |
25.0 |
1.7 |
|
L2.0 |
20.0 |
30.0 |
1.7 |
|
L2.54 |
25.4 |
38.1 |
1.7 |
|
L3.0 |
30.0 |
40.0 |
1.7 |
|
L3.27 |
32.7 |
45.0 |
1.7 |
|
L4.0 |
40.0 |
60.0 |
1.7 |
Tolerance: +/- 0.1mm
BACK TO TOP
LS-
LEBOW STANDARD UHV SANDWICH rings are designed for UHV applications where no
adhesives or epoxy can be tolerated. They are made of 304 stainless
and baked at 400oC
in high vacuum. LS rings cannot normally be used with mesh supported
foil or B, Be, Ge, or Si over about 0.5 microns thick because organic
adhesives are required.
 |
UHV Sandwich mounted Al foil. The UHV rings are vacuum baked
before mounting the foil at 300oC
and are completely organic free. |
|
Inside Diameter |
Outside Diameter |
Thickness |
Hole Circle |
Screws |
| LS0.5 |
5.0mm |
17.0mm |
3.0mm |
14.3mm |
2 |
| LS1.0 |
10.0 |
17.0 |
3.0 |
14.3 |
2 |
| LS1.34 |
13.4 |
22.3 |
3.4 |
19.5 |
3 |
| LS1.5 |
15.0 |
25.0 |
3.4 |
21.7 |
3 |
| LS2.0 |
20.0 |
30.0 |
3.4 |
26.7 |
3 |
| LS2.54 |
25.4 |
38.1 |
3.4 |
34.8 |
4 |
| LS3.0 |
30.0 |
40.0 |
3.4 |
36.7 |
4 |
| LS4.0 |
40.0 |
60.0 |
3.4 |
53.4 |
6 |
|
|
|
|
|
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|
C- CUSTOMER supplied mounting rings: Machined rings 0.5 mm or
more thick with a minimum 5.0 mm width
for foil bonding are preferred. Rings must be made of stainless steel or other
low expansion material if the foil will be heated or baked.
Aluminum rings are suitable only for aluminum or similar foil. User supplied rings in quantities of over 10
should be approved before your order is placed. Specify these as C followed by the
inside diameter (or diagonal), i.e., C25.4mm or C1inch for a 1 inch customer
supplied ring. Extra charges may apply for difficult rings.
V- VAT RINGS to fit VAT 01032-UE(or CE)**-X (X=window) valves, edge
threaded, are in stock with 10mm and 15mm inside
diameter. Adaptors, to allow
using L1.0 rings in VAT valves, can also be supplied.
BACK TO TOP
PACKAGING Foils are individually packed in plastic vials
or plastic boxes. These are
reliable
shipping containers but are not intended for long-term storage. Most thin metal
foils oxidize and all should be stored under an inert atmosphere or vacuum.
Readily oxidized materials are shipped under dry nitrogen.
 |
A standard Lebow Company shipping
vial containing a mounted filter. |
MARKING All foils are marked on the ring with the foil
material and lot number in low volatility ink. Foil rings can be supplied
without marking or with scribed markings as required.
PRICE CLASS This is our method of denoting the
fabrication difficulty and is the price indicator.
| Class
1
- |
Economical, readily fabricated. Sizes limited by
equipment to 200mm. |
| Class 2- |
Moderately priced, reliably fabricatable.
Maximum size 100mm, larger for some materials. |
| Class 3- |
Challenging, can be fabricated into top quality
foils. Maximum size, 50mm, larger for some materials. |
| Class 4- |
Difficult materials, the fabrications of which may
offer major technical challenge. Our experience with these
materials indicates that occasional closed cracks or a tiny patch
may be unavoidable. Limited to 15-25 mm, occasionally larger. |
| 2 or 3 x Class 4- |
Foil requiring extraordinary technology with
significant technical risk. This foil is so difficult to make
that it is effectively offered on a "Best Effort"
basis. The B foil manufacturing process is particularly
unstable. Size limits, 10-15mm. |
METROLOGY
1) MICROBALANCE 30 gm capacity, 1 microgram resolution.
2) ALPHA SPECTROMETER .1-10 micron, .05 micron resolution.
3) ULTRA MICROMETER 100 micron capacity, 1%/0.02 micron resolution.
4) OPTICAL DENSITOMETER 1 part in 109.
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Registered trademarks: Parylene N- Union Carbide, Kapton, Mylar, and
Teflon- DuPont
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