Radon/Thoron concentrations as well as gamma background are also continuously provided as adding quantities.
RTS CAM / CCAM family includes very compact and smart Radioactive Aerosol Monitoring Instruments dedicated to sample and measure the radioactive contamination in air, due to alpha and beta emitters, and to provide gamma dose-rate as adding information. To allow light weight and compactness, the relevant shielding and compensating functions are performed electronically by means of appropriate measuring procedures and algorithms.
The family is actually composed by: CAM-01 (wall mounting), CCAM-11 (two separate modules for wall, desk or cart mounting, remotizable measuring head), CCAM-TF (tape filter model), CCAM-12 (very compact model). CCAM-11STT, CCAM-12STT and CCAM-TFSTT are the widely used trolley units. DCAM-22 is the special alpha/beta & gamma dual unit.
CAM/CCAM units allow the continuous monitoring of the radioactive aerosols collected on a circular filter from air (a standard circular one 47 mm diameter for ‘01’, ‘11’ and ‘12’ units, tape-filter for the ‘TF’ units), using spectrometric techniques. They perform the on-line alpha and beta measurement from the filter using a proprietary algorithm that is a combination of ‘peak/tail fitting/simulation’ and of ‘region-of-interest’ (5-ROIs) methods to evaluate the presence of long lived alpha (as example: Pu-239) and beta emitters. The main results are the associated concentrations in air (in Bq/m3 or DAC). Aerosol monitoring is carried out using a solid state detector connected to a dedicated low-noise charge preamplifier (RTS PA-03C) and a monitoring processor (RTS MAB-03C) including an input amplifier/shaper, a fast MCA section for 1024 channels, some auxiliary circuitries. The spectra are acquired by the monitoring processor and related counts, after the application of the suitable fitting methods, are divided into a 5-ROIs histogram. The counts from these ROIs are then operated on using the final part of the algorithm to identify the contributing components of alpha and beta emitters, and determine whether they are artificial or naturally occurring (radon and thoron progenies).
The systems work automatically, fully controlled by the dedicated processors, and are specifically designed to meet the needs of continuous monitoring of radioactive alpha/beta particulate contaminants of the air in applications like plant workplace or ventilation monitoring as well as environmental surveillance networks.
Air sampling is accurately measured and controlled to ensure constant and precisely known air flow through the filter. The mechanisms for filter replacement is manual by a suitable slide or automatic for the tape model, very reliable and simple.
On-line measurements with programmable parameters and alert/alarm thresholds are continuously performed during sampling. Alpha and beta ‘artificial’ concentrations in air (Bq/m3 or DAC), as well as alpha and beta ‘artificial’ exposures in air (Bqh/m3 or DACh), are evaluated during cycles at each refresh and at the end of each measuring cycle. Alpha and beta total activities present on filter (Bq) are also evaluated as adding quantities as well as Radon and Thoron concentrations in air (Bq/m3).
Gamma background (dose-rate) is measured by means of a dedicated probe allowing to perform the real-time (dynamic) gamma background compensation on beta measurements
The following main functions are provided: Flow-rate, pressure drop through the filter and temperature measurement, Filter, flow and pressure drop management, Alpha/Beta spectrum acquisition and readout, Gamma background measurement/compensation, Algorithm processing and 5-ROI histogram readout, Evaluation of artificial concentrations and exposures in air, Evaluation of gross collected activities (and related variation), System parameters set-up, Management of alert/alarm thresholds and trips, Detection/management of failures, Test, calibration and simulation operation, Generation of outputs, Data storage (Data, Alarm Record and Log) and communication.