LiF:Mg,Cu, P THERMOLUMINESCENT PHOSPHOR & PELLETS

MCP-type ultra-high sensitivity thermoluminescent pellets are the latest development in radiation protection dosimetry. They are an important supplementary dosimetry tool to the standard LiF:Mg,Ti type pellets (MTS-N) especially for low-dose measurements and are unmatched in the range below tens of *Gy. Featuring a low, stable zero reading with a detection threshold of 50 nGy (200 times better than the standard LiF:Mg,Ti), they are 30 times more sensitive to gamma ray doses.
Our MCP-type ultra-high sensitivity detectors are solid circular pellets of 4.5 mm diameter with any required thickness in the range 0.3*1.5 mm (standard 0.9 mm).
The detectors consisting of 100% LiF:Mg,Cu,P TL phosphor are manufactured under the code name MCP (Mg, Cu, P), with an additional symbol, representing the isotopic content of lithium: MCP-N (natural abundance), MCP-6 (6Li-enriched), MCP-7 (7Li-enriched). The excellent dosimetric properties of the phosphor are enhanced by our original, carefully tested and controlled sintering procedure. The phosphor is also available in the form of powder.
The MCP chips are rather sensitive to thermal treatment which makes it important to use an annealing oven with good temperature stability. A summary of TL properties of MCP materials is given in the table overleaf. The extremely high sensitivity of MCP detectors opens new possibilities in the study of very low doses, e.g., of the variations of natural background throughout the day or monitoring of doses of persons briefly visiting nuclear installations. In measurements of doses below 1 *Gy the natural gamma background should be taken into account.

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Annealing conditions
Pre-irradiation: 240oC for 10 minutes followed by rapid cooling to room temperature Post-irradiation: 100oC for 10 minutes

To maximise detector sensitivity we recommend that they be rapidly cooled after 240oC annealing, e.g. by placing the container with hot detectors on a large aluminium block.

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Main features of MCP pellets

  Form   solid disc 4.5 mm diameter, of selected thickness
  Effective atomic number Z   8.2
  Density [g.cm-3]   2.5
  TL emission spectrum [nm]   385
  Relative sensitivity to TLD-100   40
  Main peak temperature [oC]   210
  Zero dose reading [nGy]   100
  Detection threshold [nGy]   50
  Linearity range [Gy]   10-7 10
  Repeatability   < 2%
  Photon energy dependence 30 keV - 1.3 MeV   < 20 %
  Batch homogeneity [1 SD]   < 5 %
  Thermal fading [% at room temperature]   < 5% / yr
  Fluorescent light effect on fading and zero reading   negligible at laboratory light intensity
  Reusability   unlimited
  Dose rate influence   independent

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Special offers
Apart from offering the above described standard detectors, we are ready to fulfil any special requirements of our Customers, regarding detector size (pellets of diameter ranging from 1 mm to 15 mm have been produced), material composition, adjusted detector sensitivity, powder grain size, etc.

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