Features

• Automatic sample changer with 50 or 100 sample capacity
• Automatically identifies and compensates for radon, thoron and progeny interference
• PIPS® silicon gas-less detector
• Developed primarily for air filter analysis
• NiMH battery power provides 6+ hours of continuous operation
• Universal, auto-sensing power supply
• Scintillation cosmic guard detector
• Molded low background passive lead shielding with interlocking design, 4 in. thick
• Compatible with essentially all filter types and sizes from 25 mm to 60 mm diameter
• Carriers available for NFS, PAS and SAS mounted filters
• Includes mobile cart
• Stores up to twenty-six standards; allows for up to ten counting procedures and ten independent calibrations
• Automatic system calibration for background, alpha and beta efficiencies for all ten calibrations with no operator intervention
• Automatic daily QC checks of alpha and beta backgrounds and alpha and beta efficiencies
• Compatible with iLink™ iSeries™ Communications Software for remote setup and download of data to a computer
• CE compliant

Description

The Canberra iMatic™ is a firmware based, automatic, low background, gas-less alpha/beta counter designed specifically for the analysis of air filters and smear or swipe samples. The iMatic discriminates both radon isotopes and their progeny from transuranic and fission product materials on the samples. It uses a solid state silicon PIPS detector for alpha and beta detection; can be operated continually for over six hours with internal batteries and is totally self contained. The iMatic represents a major technological breakthrough in air filter analysis.

The Problem is Radon

Counting air samples from either CAM units or stationary samplers can pose serious problems for the health physicist. Why? Radon isotopes and their respective progeny emit alpha particles with energies from 6.0 MeV to 8.78 MeV. The low energy peak tails from these detected alphas mask the spectral region where alphas from transuranic (uranium, plutonium, americium and curium) alphas would be (See Figure 1). Even the smallest amount of radon interference on a filter paper can cause 'falsely' elevated DAC values. Radon is the problem, but the real difficulty is knowing when the values are false - caused only by radon interference and not a plutonium or uranium release.

The iMatic Approach

The Canberra iMatic, like its predecessor, the iSolo, solves this problem with a new and innovative approach. Gone are the days of waiting for hours or even days for radon's isotopes interferences to decay away before an actual activity is known.

With the iMatic, you will know within minutes if the alpha activity is due to transuranic or fission product material or from naturally occurring radon. A pulse height spectrum, similar to the one shown in Figure 2, is acquired in a multichannel analyzer in the iMatic.

A series of peak evaluations are performed on the original acquired spectrum. When all of the corrections are made, a residual spectrum, similar to the one shown in Figure 3 (shown in red) results. It is from this residual spectrum that the iMatic reports radon compensated, true alpha and beta activity on the front panel LCD display.

Not only are the numerical results shown on the iMatic's screen, but the 256 channel spectra of both the original and radon compensated data can be seen as well. (See Figures 4 and 5). The spectra can be viewed in linear or log scale, and the scale can be set automatically or manually by the user. The X axis of a compensated spectrum is shown in the middle of the display to accommodate channels with negative data.

Figure 4. Original data shown in log scale. Figure 5. Compensated data shown in log scale.

Complete Solution The Canberra iMatic is a complete solution for the analysis of filter and filter type samples. The iMatic, unlike any other automatic alpha/beta counter, is based on the same technology as Canberra's iCAM. The iMatic provides reliable measurements of transuranic and fission product activity on filter samples in the presence of radon interferences. Using a patent pending technique, the iMatic applies auto-adaptive spectrometric compensation for the radon interferences.

The iMatic radon compensation algorithm adjusts to all types of filter media from glass fiber filter media for smear analysis to Millipore® membrane type filter media for air sampling. The iMatic adapts to these different filter media types automatically. No additional calibrations or special instrument settings are required. The iMatic lets health physics technicians focus on their job without calculators, manual ratio calculations, downtime, and guesswork. Two built-in, operator-adjustable alpha and beta alarm levels are provided to alert the operator when a critical limit has been exceeded. The operator can then proceed quickly with the necessary actions without the added worry of making a mistake. The iMatic anti-coincidence guard detector provides rejection of external gamma and cosmic radiation to minimize the overall system alpha and beta background.

The anti-coincidence guard detector utilizes a customized 'wrap around' plastic scintillator. The guard detector surrounds the sample detector optimizing the rejection of low angle external gamma and cosmic events. The light pulses generated within the scintillator are coupled to a photomultiplier tube where the light is converted into an electrical signal that is used to anti-coincidence gate the data collection of PIPS sample detector events. When throughput and sensitivity are essential, the iMatic is unsurpassed.

Control touch panel.

The iMatic provides the system operator with gross alpha/beta results, but that is only the beginning of what it does. Pulses from detected charged particles are sorted by energy. A lower level discriminator is set at 125 keV and any particle with energy greater than this threshold but less than 2.2 MeV is identified as a beta. A particle with energy greater than 3 MeV and less than or equal to 9.6 MeV is identified as an alpha. The 3 MeV to 6.4 MeV portion of the alpha region is further divided into three overlapping regions; a uranium region, an americium/plutonium region and a curium region. These regions allow the user to reasonably determine which nuclide is present in a sample if a high compensated alpha result is encountered. The following regions may be selected to be reported on the iMatic hardcopy printout. Energy values are approximate.

• Total Alpha Region: 3.0 MeV to 9.6 MeV
• Uranium Region: 3.0 MeV to 5.0 MeV
• Uranium, Am and Pu Region: 3.0 MeV to 5.6 MeV
• Curium Region: 3.0 MeV to 6.4 MeV
• Total Beta Region: 125 keV to 2.2 MeV

Standalone Instrument - No Computer Required

The iMatic is a firmware based instrument and does not require a computer to set up or operate. The entire program is stored in flash memory. New programs may be downloaded as a file via HyperTerminal™ using the RS-232C interface. There are no PROMs to change and no housings to remove to get to them. The entire process to upgrade the iMatic program takes less than five minutes.

iLink iSeries Communications Software

If computer control and/or the ability to download iMatic results into a Microsoft® SQL Server database are desired, iLink iSeries Communications Software is available for this purpose. iLink provides the operator of iMatic systems the ability to program the majority of the iMatic features with a computer, rather than through the use of front panel buttons. iLink also includes an embedded version of the Microsoft SQL Server database for the storage of iMatic data.

All iLink functions are controlled via an intuitive graphical user interface. These functions include the ability to enter sources, enter sample and guard detector voltages and thresholds, setup the system printer and print mode, edit or create iMatic report templates, establish iLink and iMatic securities, create User, Calibration and QC procedures, backup and restore iMatic system personalities, and export data in comma separated (CSV) or Tab-Delimited formats. iLink is compatible with the Microsoft Windows® 2000 and XP Professional operating systems. Multiple iMatics can be interfaced to one computer, depending on the number of available ports there are in the computer.

Rear view of shield.