In my next set of experiments I am going to look for alpha-decay acceleration by subjecting a 210Po source to a number of extreme stimuli in hopes to affect the natural rate of radioactive decay. Therefore I decided to compare a good old Eberline AC-3 alpha probe connected to an MCA-LITE and running the PulseCounter software to a state of the art Mirion (formerly Canberra) SA-100 smart probe.
The probes have identical design and geometry: they both employ a 100 cm2 ZnS(Ag) scintillation detector. The only difference between the probes is that the SA-100 implements a ‘smart probe’ architecture and requires Canberra Smart Probe (CSP) software to operate.
The smart probe architecture is rather neat: all CSP probes come with an integrated HV power supply, a preamp, a shaping amp and a USB interface. All you need is a copy of Canberra Smart Probe software and a special (proprietary) USB cable to connect the probe to your PC – Fig. 1.
The idea behind the ‘smart probe’ architecture is to provide a unified interface for acquiring counts (or spectra) from a variety of radiation detectors. All Mirion smart probes require the same CSP Smart Probe USB PC cable (~$300). If you do not want to spend the money you can make the cable yourself by attaching a Lemo connector to a USB cable (Mirion provides the pinout). However, you will still have to buy the CSP Smart Probe software (another $200-300). This, however, is a small investment considering that you need only one cable and only one copy of the software to operate just about any Canberra / Mirion smart probe.
When you lunch the CSP software you must login: type USER for login and 0000 for password and you are in – Fig. 2.
Then from the probe list select the type of the probe you want to use (the probe must be connected to the PC) and click on the ‘Acquire Measurements’ or the ‘Data Logging’ icons to capture counts.
Personally, I find CSP 3.0 software a bit flaky as it occasionally fails to connect to my probes. I do not know if this is a USB compatibility issue or something else, but it sure is annoying. I was also surprised to see counts only in CPM (counts-per-minute) without the CPS (counts-per-second) option. The CSP software is not as feature-rich as the PulseCounter software, but it gives the counts – Fig. 3.
The CSP software does not provide spectrum (although you can’t expect any energy resolution from this probe).
If you login as an administrator you can adjust the probe parameters such as the detector threshold and calibration, although I do not recommended it. The SA-100 probe comes with the factory calibration and sensitivity to common isotopes stated on the probe. Therefore any adjustments of the probe settings would invalidate the stated sensitivity figures.
Conclusion
Canberra SA-100 probe and the CSP software are easy to use. The software works quite well for sample counting. Therefore there should be no issues measuring activity and logging the results. Buy one on eBay for only $995, complete with the CSP software and the CSP USB PC cable.