Cleaning Procedure
After cutting to a thickness of 5mm, the 25mm diameter disks were:
- Washed
- Ultrasonic Clean with 10% Decon 90
- Rinsed with deionised water
- Two Ultrasonic Cleans with deionised Water
- Dried @50'C for ~2Hr
Test Procedure
Four examples of each resin (except Varian Torr Seal and the 'domestic' Araldites) were prepared immediately before pump testing following the manufacturers recommended cure time and the cleaning routine outlined above.
Four samples of each resin type were loaded into the vacuum test chamber and pumped by a rotary pump (Alcatel 2012) for 1 minute followed by the turbo-molecular pump (Pfeiffer TPH240). The vacuum recording started after a pump-down time of 5 minutes by which time the vacuum was around 1e-4Torr.
Four vacuum measurements were made:
- Varian MultiGauge Thermocouple. The gauge output was only used to monitor the backing pressure and to confirm that the vacuum was suitable to start the turbo-molecular pump.
- Varian MultiGauge Cold Cathode and/or Bayard-Alpert UHV gauge.
- Thermo (VGQ), Residual Gas Analyser. The spectra were used to characterise the different resins.
- Thermo (VGQ), total pressure measure. This vacuum measure was used to monitor the pump-down time.
This pump test was performed 24hrs after the resin was mixed. The vacuum was recorded by the Thermo (VGQ) in total pressure mode and confirmed by the Varian Cold Cathode gauge and presented as the final vacuum reading.
We have provided a comparison of all of the pump tests via a downloadable PDF document.
| Resin | Final Vacuum (2Hr) | Pump Graph (PDF document) |
|---|---|---|
| None | 2.8e-7 Torr |
Document
tp blank 2 hours (8.95 KB / PDF)
|
| EpoThin | 8.4e-7 Torr |
Document
tp epothin 2 (8.8 KB / PDF)
|
| TransOptic | 1.4e-5 Torr |
Document
tp transoptic 2 (10.67 KB / PDF)
|
| KonductoMet 1 | 4.8e-6 Torr |
Document
tp konduct 2 (10.03 KB / PDF)
|
| Korapox 439 | 5.4e-6 Torr |
Document
tp korapox 2 (10.34 KB / PDF)
|
| Epofix | 3.2e-6 Torr |
Document
tp epofix (13.38 KB / PDF)
|
| Specifix 20 | 5.1e-6 Torr |
Document
tp specfix 2 (10.97 KB / PDF)
|
| Ciba Geigy | 2.5e-6 Torr |
Document
ciba pump 2 (10.36 KB / PDF)
|
| ProbeMet | 5.4e-7 Torr |
Document
tp probemet 2 (8.78 KB / PDF)
|
| Robnor Resin | 3.3e-6 Torr |
Document
tp robnor 2 (8.94 KB / PDF)
|
| Epoxicure (Room Temperature) | 3.4e-6 Torr |
Document
pump epoxicure rt (10.75 KB / PDF)
|
| Epoxicure (cured at 65oC) | 3.6e-6 Torr |
Document
epoxicure 65 (10.83 KB / PDF)
|
| Petropoxy | 3.7e-6 Torr |
Document
tp petropoxy 2 (8.87 KB / PDF)
|
| EpoHeat | 4.2e-6 Torr |
Document
tp epoheat 2 (10.2 KB / PDF)
|
The 24Hr pump test was performed ~30 days after the resin was prepared and is believed to give a good indication of the resins suitability for the practical preparation of material for SIMS analysis. Throughout the testing period the empty vacuum chambers residual gases and ultimate (24hr) vacuum were routinely monitored to check how these parameters varied over time. The results show a slight but steady improvement in the ultimate chamber vacuum over the 30 day test period.
We have provided a comparison of all of the pump tests via a downloadable PDF document.
| Resin | Final Vacuum (24Hr) | Pump Graph (PDF document) |
|---|---|---|
| None | 7.12e-8 Torr |
Document
uhv24blank (68.83 KB / PDF)
|
| EpoThin | 1.64e-7 Torr |
Document
uhv24ethin (23.94 KB / PDF)
|
| TransOptic | 3.10e-7 Torr |
Document
uhv 24 topt (42.45 KB / PDF)
|
| KonductoMet 1 | 2.40e-7 Torr |
Document
uhv24kmet (37.54 KB / PDF)
|
| Korapox 439 | 1.10e-7 Torr |
Document
uhv24kpox (41.12 KB / PDF)
|
| Epofix | 1.60e-7 Torr |
Document
uhv24efx (71.54 KB / PDF)
|
| Specifix 20 | 2.10e-7 Torr |
Document
uhv 24 sfx (43.7 KB / PDF)
|
| Ciba Geigy | 1.90e-7 Torr |
Document
uhv24cg (36.68 KB / PDF)
|
| ProbeMet | 1.60e-7 Torr |
Document
uhv 24 pmet (23.93 KB / PDF)
|
| Robnor Resin | 1.11e-7 Torr |
Document
uhv 24 rr (26.44 KB / PDF)
|
| Epoxicure (Room Temperature) | 1.70e-7 Torr |
Document
uhv24ecurert (40.9 KB / PDF)
|
| Epoxicure (cured at 65oC) | 1.60e-7 Torr |
Document
uhv 24 ecure65 (44.24 KB / PDF)
|
| Petropoxy | 1.20e-7 Torr |
Document
uhv 24 pxy (25.41 KB / PDF)
|
| EpoHeat | 1.40e-7 Torr |
Document
uhv24eheat (36.7 KB / PDF)
|
A final 2Hr pump test was performed ~3 months after the resin was prepared. The samples were kept in a desiccator and the test chamber continually pumped over this ~3 month time period and the base vacuum improved. The results show a significant improvement in the ultimate chamber vacuum after 3 months hardening.
A comparison of all of the pump tests is provided via a downloadable PDF document.
| Resin | Final Vacuum (2Hr) |
|---|---|
| None | 2.8e-8 Torr |
| EpoThin | 5.3e-8 Torr |
| TransOptic | 1.5e-7 Torr |
| KonductoMet 1 | 9.8e-8 Torr |
| Korapox 439 | 7.1e-8 Torr |
| Epofix | 7.4-8 Torr |
| Specifix 20 | 8.5e-8 Torr |
| Ciba Geigy | 5.8e-8 Torr |
| ProbeMet | 5.9e-8 Torr |
| Robnor Resin | 6.6e-8 Torr |
| Epoxicure (Room Temperature) | 6.9e-8 Torr |
| Epoxicure (cured at 65oC) | 5.9e-8 Torr |
| Petropoxy | 9.3e-8 Torr |
| EpoHeat | 6.6e-8 Torr |
Residual Gas Analysis
The residual gases within the vacuum chamber were routinely monitored during the pump tests. These gases, although not all identified, can provide a distinctive 'fingerprint' of the resins.
Discussion of Results
Comparison of the final vacuum achieved for each resin under the three test conditions is illustrated in our downloadable PDF document.
The relative vacuum achieved has been calculated from the final vacuum recorded minus the base vacuum of the chamber. It demonstrates that after ~3 months the same vacuum maybe achieved that previously took 24hrs.
Epothin and ProbMet both performed well under all 3 test conditions.