
LS 6000 Scintillation System User’s Manual
PN 247971-F
5-8
Data Calculation
DPM
Setting Up Auto DPM
When editing a User Program, from the Data Calculation Menu (Figure 5.1), choose “Auto
DPM”. The prompts displayed for this program are the same as described for CPM. Refer to
Setting Up CPM/Xtal CPM Section 5 for information on setting these prompts.
Loading Samples for Auto DPM
The same loading sequence used for CPM is used for DPM. Refer to Loading Samples for
CPM/Xtal CPM Section 5.
Results for Auto DPM
To count the samples, refer to Section 3.4. It is recommended that Auto Calibration be
performed before the samples are counted. A typical printout in standard format for Auto
DPM is shown in Figure 5.6.
5.5 DPM
The Counts per Minute (CPM) Program provides a measure of the activity as observed by the
instrument. The Disintegrations per Minute (DPM) Program provides a measure of the
absolute activity within the sample.
When CPM data is used, It is assumed that the counting efficiency of all samples is the same.
In practice, however, counting efficiency is affected by a wide range of factors. Some of these
factors are choice of liquid scintillation cocktail; amount of cocktail;
type of sample; amount
of sample; and size and type of vial. The use of DPM makes the results independent of these
factors.
Single, Dual and Triple Label DPM programs are available (if installed) when Liquid is
selected as the scintillator. When Xtal is selected as the scintillator, Xtal DPM is available.
Refer to Section 5.6 for more information on Xtal DPM.
Figure 5.6 Typical Printout for Auto DPM.
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