Tri-Carb 4910 Liquid Scintillation Counter User Guide (DRAFT)

Owned by jr_novak
Last updated: Dec 19, 2021
9 min read

LSC General Information

The detector should not be exposed to ambient light when powered on. 

It is best to operate the system with the lid closed. 

From Brian Arias at Perkin Elmer:

The lid can be open briefly during counting but, we don’t recommend it as ambient IR light can affect results as well as sensors.  The light shutter over the counting chamber should block any stray light but, we still don’t advise it staying open for long.  Please make sure vials are tall enough to block the vial sensor at counting chamber which is opposite the reflective adhesive disk above the loading hole.

The cassettes do not need to be balanced in weight as SNC is also run with only 3 vials loaded on left side of rack.  Even if rack is not parallel to front/rear wall when transfer is started, the mechanism should give ample time before rack is transported from left to right and vice versa.  Make sure transfer pins on the silver wheels located on front and rear walls ( 2 on each wall) are at the identical orientation other wise the racks will jam.

If user is doing maintenance, ensure the detector is not powered on. 

A spike in background levels in the 0 to 4 kev channels may indicate a possible light leak.

  • There are flash drives inside the LSC that contain backups of the software and a hard drive image.  These would be used in case there is a malfunction with the system. Do not remove them from within the LSC.

  • Log in information:

    1. User account: User name: QuantaSmart; Password:QS (capital letters)

    2. DAQ account : DAQ, DAQ445px

    3. Administrator account: No password

  • Once you select Assay type (CPM, DPM, etc.) you cannot change it.

  • Use SIS (spectral index of sample) for CPM measurements

  • DPM measurements take longer because they count against the barium first.

  • Vendor does not recommend using the ‘subtract background’ option

  • Leave the ‘Static Controller’ on in the Count Corrections tab

    1. Wiping vials with alcohol can help reduce static in dry environments

  • To use an assay: Right click on a flag on the left side of the window and select assign assay. Select the file and select OK.

  • DPM tests require the half-life in the Sample Nuclide Group Set up window

  • Replay can be used to reprint reports and make slight edits

Terminology

  • IPA = Instrument Performance Assessment

  • SNC = Self Normalization Calibration

  • IPA and SNC are the same. These both refer to the calibration procedure.  The IPA menu is used to setup the calibration procedure.  The SNC flag is used to mark the rack in the LSC that is set up for the calibration.

  • Assay: Measurement procedure file.  These files dictate the measurement procedure and may be reused.

  • Protocol: The flags for the cassettes that allow the system to identify which cassette is being run

  • Cassette:  The sample holders that carry the sample vials to the detectors

Parts List

Cassettes:

  • Cassette for Standards, large vials: Large Vials SNC Class 7601280 

  • Cassette for Standards, small vials: Small Vials SNC Class 7601286 

  • Cassettes for Large Vials, Basic Kit: Varisette Sample Holders- Large Vial PEPN 7000725  PN5072520

  • Cassettes for Small Vials, Basic Kit: Varisette Sample Holders- Small Vial PEPN 7000725  PN5072521 

Vials:

Vials must meet certain specifications.  The lid can NOT be larger than the vial itself.  The vials 'drop' through the bottom of the cassette and are moved to the detector.  If the vial lid is too large, the vial will get stuck.  Current vials for the LSC are MB0082 and MB0081.  The vials must not be too short.  The LSC detects the presence of sample through a laser and reflective disk.  If the vials are too short, the laser will not detect the vial and the vials will not be measured.

  • Large Vials: 20 mL HDPE Vials, Fisher Scientific, MB0082

  • Small Vials: 8 mL HDPE Vials, Hinge Cap, Fisher Scientific, MB0081 

Alternate Vials from Perkin Elmer:

  • 8 mL hinge cap viles, case of 2000, Reorder # 6000480

  • Pico Glass Vial, 7 mL, with foil-lined, white urea screw caps, case of 1000, Reorder # 6000167

Boards:

  • ADC Interface Board 7101655

  • Sample Changer Interface Board 7101659

Protocol Plugs:

  • Protocol plugs P/N 7000674 and P/N 7000675

Cassettes.  White cassette is for small vials.  Black cassettes are for the large vials.

File Structure

All files and software for the LSC are stored in the C:\\Packard folder on the PC.  There are no files stored in the Program Files folder.

Users can review file paths assigned to an assay by selecting the protocol and selecting File: Data Paths

For calibrations (SNC/IPA) the file path is set from the IPA menu.  For measurement assays the file path is set in the assay definition window.

Recommended File paths:

Calibration Files: C:\Packard\TriCarb\IpaResults

Measurement Files: C:\Packard\TriCarb\Results\Default 

Calibration Procedure

The LSC should be calibrated weekly if the system is being used constantly.  If the system is used only occasionally, then a calibration should be run prior to any measurements.

A full calibration procedure takes an hour and 15 minutes.  The 14C and 3H measurements take a total of 15 minutes while the background measurement takes 1 hour.

  1. Load the standards in the appropriate locations on the rack labeled with 14C, 3H, and BKG.  

  2. Place the SNC Flag on the cassette and place the cassette into the LSC

    1. Make sure the sliding tab is all the way out toward the left or the LSC will think the run is completed and will not measure the standards.

Standards in rack with SNC flag (protocol) set up for a run.  Note the flag is all the way to the left.

       3. Open the IPA menu 

 

 

       4. Verify the DPMs for each standard. Update if necessary.

                a. Each standard is labeled with the DPM information.  This information should only need to be updated if using a new standard.

      5. Ensure the "Save Copy of IPA data to text file" box is checked.  Assign a file name to your calibration run.  This will automatically save a copy of the results.

                a. File path for calibrations should be stored in C:\Packard\TriCarb\IpaResults

      6. Select OK

      7. Select the SNC assay from the list on the left side of the window.  The SNC label will be highlighted

      8. Select the Green flag at the top left side of the window

      9. Calibration will begin to run.

a. During the calibration, the screen will update with the status of the run.  Note: if any other cassettes are flagged as ready to run (flag to left) they will be run immediately after the calibration finishes.

Creating an Assay

1. Select File: New Assay

2. Select the assay type to use and click ok What is our recommend Assay type?

3. The Assay Definition window will open.  In the Count Conditions tab click on the field NAME to assign a nuclide group.

4. The nuclide library will open.  Select an existing nuclide group or add a new group to the library.  Then select OK.

5. In the Assay Definition window in the Count Conditions tab set the count time, the number of repeat counts and the number of count cycles.  It is recommended by Perkin Elmer to NOT use the background subtraction option.

     a. Repeat Sample Count: repeat the measurement of the sample immediately the number of times set in the field

     b. Number of count cycles:  Measure everything in the cassette, move the cassette around and remeasure everything in the cassette.  The measurement flag won't be moved until the total number of count cycles has been reached.

6. In the Count Corrections tab ensure the Static controller option is selected.

7. Select the Report Definitions tab to define what data is output in the report, the order the data is output, and the format of the output.

   a. The Report list box will list the existing report name (if editing an existing assay) or a generic report name.  Click Add to create a new report format.

   b. In the Report Fields box, place a check mark in the 'use' column for the fields that the user wishes to have in the final report

   c.  The order of the reported fields can be modified using the Report Field Order menu at the bottom of the window.

8. In the Report Output tab, select what report format to use for the assay from the report list.  Multiple report formats can be assigned to one assay.  If they are visible in the report list, they will be generated. User can also set the program to auto print the report, set the software to autosave the data and assign a name to the file.

9. In the Worklist tab the user can assign names to samples and their positions in the cassette.  This can be particularly useful for repeat wipe tests of routine locations.

10. Select OK to create the assay or Apply to apply changes to an existing assay.  Assign a name to the assay in the pop up window.  The file will be autosaved to the C:\\Packard\Assay folder.

Notes Regarding Assays:

  • The QuantaSmart Program has 30 protocols or assays. These can only be deleted from the C:\\Packard folder manually.  A user cannot delete an assay from within QuantaSmart

  • To use an assay: Right click on a flag on the left side of the window and select assign assay. Select the file and select OK.

Starting Measurements

 

Assign an Assay

  1. Load Samples in a cassette in the proper order and place a protocol flag on the cassette.  Make sure the flag is slid to the left.

  2. Double click on the protocol that matches the protocol flag on the cassette.  The protocols are the numbered flags on the left side of the screen.  How do we delete> 

  3. Select an assay from the file list

  4. Verify the file paths.  If the 'Use Default' box is unchecked, the user can change the file output location

4. Select Ok

5. Close the LSC Lid

7. Select the green flag at the top of the screen.  LSC will begin searching for and measuring protocols.  Any protocol flags it 'finds,' it will measure.  It is recommended to only have your designated samples in the LSC or have the flags pushed to the right so the system skips these cassettes.

Maintenance 

Before doing any maintenance on the detectors, ensure the detectors are powered off.  If the detectors are removed from the LSC for maintenance and cleaning, they should be covered.  The two black covers are stored within the detector compartment on the left hand side.

Recommended Maintenance for a system in normal operation (constant use):

  1. Clean the fan filter on the back of the LSC

  2. Check the elevator, annually

  3. Check the reflectors, annually

  4. Check the Pistons, may need to be replaced every year or 2

Possible spares/required parts:

  • Power conditioner (Recommend their Power Var system. Consumer APC Units not recommended.)

  • Back up battery (Comes with power conditioner, can be purchased separately. Will run LSC for a half hour if there is a power failure)

  • Spare elevator (can be replaced as long as user has a channel lock)

Questions to answer:

How do we know what sample nuclide to use for Wipe test?  For samples run with C14 or S35, I assume we use those...

A: Depends on what nuclide is used for that expedition. If multiple, then we need to run them all (CP)