LIGO Document E960050-v13
07 Nov 2013, 16:16
27 Dec 2011, 12:02
11 Jul 2011, 15:06
04 Nov 2010, 13:05
07 Sep 2010, 13:49
30 Jul 2010, 14:01
13 May 2010, 21:40
12 Nov 2009, 14:21
16 Sep 2009, 18:26
14 Sep 2009, 13:49
29 Jul 2009, 11:42
20 Jul 2009, 18:09
- LIGO Vacuum Compatible Materials List
- Added Epo-Tek 353ND as an acceptable, though restricted, epoxy for use in bonding AMDs to TM barrels
In the next revision:
1)Based on Argonne's APS outgassing studies and UHV qualification of a high-density tungsten "alloy", we are now pursuing MT-18C (95% W, 3.5% Ni, 1.5% Cu; no Fe, nonmagnetic), with a density of 18 g/cc (class 3 per AMS-T-21014). We have a large sample on order for testing. The apparently required, relatively high vacuum bake of 500C is beyond our in-house capability.
2) Aluminum 3000 series is also inherently vacuum compatible and will be added explicitly.
3) In the next version "Copper (elemental and OFHC)" will change to "Copper (all elemental grades, such as OF, OFE, OFHC, and ETP)"
4) Some approved materials or assemblies listed in E1000193 may not have yet been added/listed in this document - check for the next version. For example, the New Focus Picomotor 830X-UHV
5) Lead-Zirconate-Titanate (PZT) is not currently listed in E960050 as an approved material. However a PZT actuator (Noliac NAC2124-C01, D1102070) has been approved for use in the aLIGO OMC (D1201439). A general note that PZT material is approved for LIGO UHV service will be added.
6) Note that Hysol Tra-Duct 2902 is also known as Loctite Ablestik 2902. This electrically conductive epoxy is approved for SEI ISI ADE capacitive sensors and for AMDs.
7) Kapton HN is approved for use in the form of tubing to provide an insulation/abrasion resistance layer for the bobbin wire which passes through the holes of the Terminal Block Mount, D070378, on its way to the Terminal Block.
8) Use of In80Pb15Ag5 solder, restricted to the CP/ESD application is approved, and will be noted in the next revision of E960050.
9) In accordance with L070132: The use of 7075 Alu, operating at room temperature, is acceptable in the LIGO UHV system. However:
* use is prohibited without prior approval based on a compelling reason (no good/reasonable alternative)
* 7075 shall NOT be vacuum baked (and RGA tested) -- it must be air baked (and FTIR tested) as part of UHV preparation
10) Tin (Sn) is inherently acceptable in the LIGO vacuum system. The alloying elements of potential concern due to their low vapor pressure are listed in LIGO-T080106 and LIGO-L080045 as Cadmium, Cd; Lead, Pb; Phosphorous, P; Selenium, Se; Sulfur, S; and Zinc, Zn.
11) Ensure that all of the materials which have passed RGA and optical contamination cavity testing are listed in E960050; see test result links collected at E1000193. For example Epo-Tek 302-3M adhesive.
12) Kester solder 6337 is approved for restricted UHV use (ref page 20 E960050). However the note "rosinless core" is incorrect. We use rosin and then deflux. To be corrected in the next release.
13) Black Nickel coatings on Alu and SS are approved.
14) The entire Chemours (formerly Dupont) series of high purity, fully fluorinated, fluoropolymer resins are acceptable for the LIGO UHV system; Specifically, the Teflon PFA 400HP resin series and the Teflon PFA 900HP Plus resin series.
15) Entry H23 of Table 1 regarding Tin-Lead Solder grade Sn63Pb37 has incorrect comment "Crimped pin connections are preferred. Rosinless core only." Crimped pins are not always preferred and the solder has a rosin core for high reliability.
16) Ni is inherently UHV compatible. Both Electroless Nickel Plating (ENP) and Electrolytic plating of Nickel is acceptable in the LIGO vacuum system. However ENP requires a subsequent heating step to drive out phosphorous. The intent of the ENP note in the document is to state that (a) maraging steel requires an anti-corrosion plating and (b) we have an approved ENP specification for the ENP process applied to maraging steel, i.e. E0900023. Electroless Nickel Plating (ENP) requires phosphorous (as a chemical reducing agent) which must be subsequently reduced by baking (see VRB response L0900024). Electrolytic nickel plating does not require phosphorous. Both can cause hydrogen embrittlement of steel.
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