Tray Cleaning¶

Required PPE

Before you start, make sure you have the following

Plenty of 5% HNO3. If not, please make a new batch.
Plenty of 30% HNO3. If not, please make a new batch.
Plenty of of techwipes in both the Radiation Room and Wet Chem Lab.
1-250 ml beaker for each tray to be cleaned.
The back drying oven by the windows is empty and does not have any samples currently drying.
Bring 1-250 ml beaker per tray to the fume hood in the rad room.
Layout 2 techwipes in fume hood. 1 for wiping surfaces + 1 for wiping hands.
Fill the tiny ultra-sonic bath in the fume hood with ~2 cm of Milli-Q.

Steps for cleaning

Pre-Clean Sample Tray¶

Knock out grains from dirty tray into radioactive waste container. Use tweezers kept in fume hood to make gentle circles around tray holes to knock lose any stuck material.
Once satisfied with grain removal, place the tray into the empty beaker.

Pour 5% HNO3 into beaker until the tray is covered.
Pour a small amount of 30% HNO3 into the beaker (approx. ¼ - 1/3 of the amount of 5% HNO3).
Swirl.
Place beaker in ultrasonic bath and turn on machine.
Check every few minutes and swirl.
Once all material is removed from the holes in the tray, remove beaker and turn off ultrasonic bath. Note: try to remove the beaker before the acid begins to turn light blue. If the acid turns light blue, cleaning is finished, and the tray is beginning to dissolve rapidly.
Pour acid into the liquid radioactive waste container in fume hood. Use finger to prevent tray from falling out while pouring acid. Be sure to carefully wipe hands after touching radioactive acid.
Pour Milli-Q into the beaker until tray is covered. Swirl. Rinse into acid waste.
Cover tray in Milli-Q and transfer to wet lab in the mineral separation lab. Be sure hands are wiped before moving to the wet lab.

Lay out 1 Kimwipe for Acetone + 2 techwipes for water.
Rinse outside of beaker with cold water in sink 3-4 times.
Fill beaker with cold water and do 3-4 high pressure washes.
Rinse bottom of tray with cold water in beaker 2-3 times.
Rinse with Milli-Q 2-3 times.
Remove tray from beaker and knock any water stuck in the tray holes into the sink.
Dry hands completely with techwipes for water.
Place tray onto techwipe for Acetone.
Using HLPC Acetone to cover the front and back of the tray and fill each hole.
Knock any Acetone remaining in the holes into the sink.
Place in drying oven by the windows with holes pointing upwards overnight to dry. Move the sign from the right side of the oven to the front of the oven that indicates that mass spec parts are drying to ensure no one uses the oven during this time.
Repeat with as many trays as you plan to clean during the session.

When finished, dispose of techwipes and gloves from the Rad Room Fume Hood into the dry radioactive waste container.