Beaker cleaning procedure
1. Remove sample names with methanol or ethanol (wear gloves and gargles)
2. Open up beakers and use Kimwipe to remove sample residues
3. Soap bath with Micro 90 soap (1%) and tap water
4. Thoroughly rinse out soap (till no bubbles form in tap water), drain all water
5. Hot aqua regia (HCL, HNO3 mixture) bath in Room 8
6. Transfer acid fumed beakers into DI water beaker, drain DI water, take to the clean lab
7. Clean acid fuming with mixture of 8NHNO3-6NHCL-1NHF
8. QD water fuming.
9. Dry down, store in clean ziplock bags and mark date and procedure.
Sample weighing procedure:
1. Mark sample name on the beaker (both cap and body).
2. Weigh the beaker
3. Zero the balance with empty beaker on it
4. Add (~200mg) sample in the beaker, cap and return it to the balance.
5. Record the weight of the sample in your lab notebook
Leaching procedure for basaltic glass
1. Add 1ml DD (double-distilled) 8N HNO3 acid to the samples, cap beakers.
2. Put beakers on 100 C hotplates for 20 minutes, then sonicate for 20 minutes, and then return to the hotplate for an additional 20 minutes.
3. Pipette out the nitric acid (as much as possible without loosing any samples) and save one or two leachates in centrifuge tubes.
4. Add 1-2 ml QD water in the beakers, sonicate for 10 minutes.
5. Remove the QD water as much as possible without loosing any samples
6. Add 1-2 ml QD water in the beakers
7. Remove the QD water as much as possible without loosing any samples
Cleaning Filament Posts
1) Remove old filament wire by filing it off
2) Put filament posts into small glass beaker
3) Put MilliQ water in beaker (enough to cover posts) and a small amount of sonicating soap
4) Sonicate for 20 minutes
5) Rinse with MilliQ until no more soap left
6) Submerge filament posts with MilliQ
7) Sonicate for 20 minutes
8) Pour our water
9) Submerge posts with methanol in reusable bottle
10) Sonicate for 20 minutes
11) Pour methanol back into bottle
12) Dry down posts in oven
Degas filaments at least two days before loading samples.† The oxidized coating that forms helps to keep samples from spreading or popping off.
Filament material is very expensive! Do not waste it!
The method described below uses the smallest possible amount of material.
1) Do not cut filament in pieces but take long piece (e.g. Re) or roll (e.g. W)
2) Spot weld end of filament to one side of the post
3) Pull filament tight over the second post and attach about 2mm
4) Take small scissors and cut filament off as short as possible
5) Attach end of filament to post
6) (filament ends standing off the posts could cause shortages under HV)
Degassing of Filaments
Insert filaments securely in the holder, check connection with the current meter (using resistance or voltage)
1) Make sure that ion gauge is OFF! (sensor 1)
2) Turn turbo pump off to open degasser (bottom control box ON/OFF switch)
3) Put in holder and attach wires
4) Check that connections are good and set up filament control
†††††††† a. turn on filament control
†††††††† b. Switch to voltage mode
†††††††† c. Hold display setting button and crank up to 60 volts (this is setting upper limit)
†††††††† d. Let go of button and voltage should drop to zero (if not connection is bad)
†††††††† e. Switch to current, DONíT hold display setting button
†††††††† f. Turn current up to 0.1 amps, if it goes up connections are good.
5) Close degasser, turn turbo pump on
6) Wait until all the green lights of the turbo pump are on (better 10 minutes)
7) Then turn ion gauge on (sensor 1, press emis.)
8) When pressure down to 2*10^-6 start turning up filament current slowly
9) Never let pressure get higher than 8*10^-6
10) Degas tungsten at 4.2 amps, rhenium at 3.8 amps for 20 min
11) When done turn off filament control panel and ion gauge
12) Allow 1 hour for filaments to cool down before opening the degasser
13) Empty degasser should be closed with turbo pump on
Loading Pb on Re filament
Sonicate Si gel 20 min.
Add sample first, 2ul or less each time till sufficient amount is reached
(* If loading standard aim for 100ng which is 2ul if the concentration is 50ppm).
Dry down samples at 1amp.
Add 2ul si gel and 0.4ul 0.5 M H3PO4.
Dry at 1.3 amps completely,
Turn the current up to 1.5 to remelt the sample, wait till the sample turns white on the filament, then turn up the filament slowly to 2.4.
Finally the sample on the filament should be smooth and white.
Conny's tip, always add in by 1-2ul sample.
For double spike, put a drop of double spike on parafilm, mix 25ng sample with 25ng spike (1:1).
Load Sr on W filaments
Load 2ul of sample first @<1.2 Amps,
Then add 2ul Sr loader @ 2.0 Amps,
Turn up the filament to a faint glow (@ ~2.†† Amps) to burn off Rb
(***If in the end the sample solidifies into a solid white paste, especially when it cracks, that means the loader is too concentrated. You should dilute the loader.)
Load Nd on Re filaments with Si gel
Sonicate Si gel for 20 minutes.
Load 2-4ul Si gel.
Dry down sample @ 1.7Amp till it becomes a thin wet film.
Turn down the current to 1.0 amp and dry down the remaining Si gel.
Add sample onto the Si gel spot then let it dry @1.2amps.
Then turn up till faint glow for 1 sec (with ambient light off).
Load Nd on Re filaments without Si gel
Melt parafilm on both ends of the filment (@ 1.5 Amp)
Load 50-100 ng Nd sample
Dry it down at 1.2 Amps
(?? + 1ul 1M phosphoric acid??)
Turn up the filament current to ~2 and wait till the parafilm evaporate.