Irradiation sources

In the Risø TL/OSL reader sample irradiation can be obtained using three different irradiation sources:

  1. beta
  2. alpha
  3. X-ray

Irradiations are software controlled allowing in-situ irradiations (minimum irradiation time of 1 s).

 

 90Sr/90Y beta source

 A detachable beta irradiator is located above the sample carousel providing software-controlled in-situ irradiations of samples. The irradiator normally accommodates a 1.48 GBq (40 mCi) 90Sr/90Y beta source. The dose rate in quartz at the sample position is approximately 0.1 Gy/s. (Sr90-sources with other activities are available on request)
The Sr90-source is mounted into a rotating, stainless steel wheel, which is pneumatically controlled. The distance between the source and the sample is 7.6 mm. A 0.125 mm beryllium window is located between the irradiator and the measurement chamber and acts as vacuum sealing.

 

241Am alpha irradiator

The alpha irradiator normally accommodates a 10.7 MBq (290 mCi) 241Am foil source, which is a mixed alpha/gamma emitter. The dominating alpha energy is 5.49 MeV (85.1%) and the dominating gamma energy is 59 keV. The source is mounted behind a pneumatically controlled shutter. The alpha irradiator option is integrated with the system lid and a sealed shaft allows operation of the irradiator under vacuum. The dose rate in quartz at the sample position is approximately 45 mGy/s.

 

X-ray Generator

Irradiation can also be achieved by means of X-rays. For this purpose we offer a Varian VF-50J (50 kV / 1 mA) X-ray unit with collimator, mechanical shutter, software-controlled Spellman high-voltage power supply and fail safe interlocks.

The X-ray irradiator incorporates an enhanced security control and fail-safe system to meet the individual ‘‘regulations for operation’’ as issued by the different local governments.

 


http://www.nutech.dtu.dk/english/products-and-services/radiation-instruments/tl_osl_reader/reader-details/irradiation_sources
17 DECEMBER 2018