Hidex 300 SL Ultra Low-Level Scintillation Counter.

Based on the popular Hidex 300 SL TDCR scintillation counter, Hidex has developed a version for detection of ultra low-level activities. The Hidex 300 SL automatic TDCR liquid scintillation counter has enjoyed tremendous success. However there are several applications where detection of extremely low levels of activity are needed. Therefore Hidex has developed an ultra low-level scintillation counter. The Hidex 300 SL Ultra Low Level counter uses the same detector principle as the standard instrument. The unit is equipped with three photomultiplier tubes to facilitate TDCR counting aswell as extremely good counting efficiency for low energy isotopes such as tritium. The new improvements in the design include:

Improvements in the passive shielding. Additional and improved lead shielding. Active guard. The instrument is equipped with a special scintillator detector, which

is positioned under the main detector. This guard detector detects cosmic radiation and other high-energy background radiation, which cause extra background pulses. When the guard detector and actual detector detect a simultaneous pulse, it is neglected.

The new Hidex Ultra Low-Level scintillation counter brings several advantages:

Dramatic reduction in background levels with variety of samples Hidex guard can be also be used to measure high activity betas. The guard detector

is separated from the actual detector, therefore it does react to high-energy betas originating from the sample and causing false counts in the guard.

Hidex guard can also be used with alpha beta separation mode as the background reduction is not based on pulse length properties.

Hidex Guard is separate from the actual detector therefore counting efficiency of standard samples is not affected and remains high over the lifetime of the counter.

Table 1. Example results with H3 in water 8ml of sample 12ml of cocktail Window Background LLoD LloD LLoD

in % in cpm in Bq/l in Bq/l in Bq/l 6 hours 10 hours 10 hours meas.

Time

Instrument

FOM

meas. time meas. time backgrd.: 24 h

2100126 25 3,5 179 5,3 4,1 3,5 2100126 33 4,9 222 4,8 3,7 3,1 2100136 25,1 3,1 203 5 3,9 3,3 2100136 31,1 4,1 236 4,7 3,6 3,1 2100136 33,5 4,7 239 4,6 3,5 3,0

Table 2. Example results with standards measured at Hidex Factory in Turku Finland.

Technical data: Width: 720 mm Height: 850 mm Depth: 630mm Weight: 180 kg

The measurement data is relative to background radiation in each laboratory.Local conditions may vary and effect the background results. Hidex reserver the right to alter specifications.

Instrument Hidex 300 SL Ultra Low Level Guard Count mode Standard Triple mode Triple mode Energy ROI 5 to 650 (full) 5 to 650 (full) 300 to 570 (optimized) Sample type C-14 LL unquenched standard C-14 LL unquenched standard C-14 LL unquenched standardCounting efficiency % 96.81 93.24 73.99

Bacgkround CPM 28.14 12.4 4.6Figure Of Merit 333 708 1179

TDCR 0.968 0.968 0.999 Energy ROI 5 to 350 (full) 5 to 350 (full) 50 to 270 (optimized) Sample type H3 LL unquenched standard H3 LL unquenched standard H3 LL unquenched standard Counting efficiency % 69.05 46.93 45.59

Bacgkround CPM 23.39 7.8 5.85Figure Of Merit 203 282 355

TDCR 0.68 0.68 0.677