Model 243

Shielded Well Gamma Sample Counter Head

Part Number: 47-1621

The Model 243, along with a pulse height analyzer system, is used for gamma ray assay and wipe test analysis. The Model 243 is shielded with 1.3 cm (0.5 in.) of lead to improve sensitivity by reducing background and other external radiation. The detector is an integrated 4.5 x 5.1 cm (1.8 x 2 in.) (Dia x thickness) NaI (Tl) crystal scintillator optically coupled to a 5.1 cm (2 in.) diameter, 10-stage photomultiplier tube.

Specifications

Indicated Use	Gamma assay
Detector (D x L)	Integral NaI(Tl) well scintillator 4.5 cm (1.8 in.) dia. x 5.1 cm (2 in.) thick
Well (D x L)	1.7 x 3.9 cm (0.67 x 1.6 in.)
Efficiency	¹²⁵I: 80% ^99mTc: 90% ¹³⁷C: 33% ⁶⁰Co: 43%
Sensitivity	Will detect 0.005 µCi gamma or 200 dpm removable contamination for ^99mTc, ¹³¹I, ²⁰¹Tl, ¹¹¹In, ¹²⁵I, ¹³⁷Cs, and ⁶⁷Ga
Background	≤ 1000 cpm in a 10 µR/hr field (optional 1.3 cm [0.5 in.] lead sleeve for background reduction: Part No. 7379-044)
Photomultiplier Tube	5.1 cm (2 in.) diameter
Operating Voltage	500 to 1200 V
Construction	1.3 cm (0.5 in.) thick painted lead wall and removable cap
Size	Base (W x L): 20.3 x 20.3 cm (8 x 8 in.) Body (D x H): 8.9 x 27.9 cm (3.5 x 11 in.)
Weight	18.1 kg (40 lb)
Shipping Weight	20.4 kg (45 lb)

Suggested Instruments

Model	Description	Part Number
Model 2000	Scaler Scaler Range: 0 to 999,999 counts Timer: 0 to 999 minutes	48-1648
Model 2200	Scaler-Ratemeter Scaler Range: 0 to 999,999 counts Ratemeter Range: 0 to 500,000 cpm Timer: 0 to 999 minutes Adjustable window	48-1651
Model 3000	Digital Survey Meter	48-4035
Model 3001	Digital Survey Meter 4 detector setups	48-4036
Model 2221	Analog Scaler-Ratemeter Single channel analysis	48-2065