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Model 239-1F Series

Alpha-Beta Floor Contamination Monitor

Features

594 cm² or 821 cm² Active Area Gas Proportional Detector
Adjustable Detector Height
Compatible with Multiple Survey Meters

The Model 239-1F Floor Monitor is a gas proportional floor monitor detector mounted on a roll-around cart. The instrument features a flow system, quick-connects, a gas bottle mount, and a means to adjust the height of the detector from the floor for optimum performance. A nuclear counting gas bottle, gas regulator, and a survey instrument are required for the operation of the floor monitor.

See the Available Configurations tab for a list of compatible meters.

Available Configurations

Meter	Part Number	Detector	Window Area	Detector Size
Model 3002	Meter: 48-4037 Cart & Detector: 48-4310	Model 43-37	Active: 584 cm² (90.5 in²) Open: 434 cm² (67.3 in²)	2.5 x 15.9 x 46.4 cm (1 x 6.25 x 18.25 in.)
Model 12	48-1702
Model 2221	48-2085
Model 2350-1	48-2594
Model 2360	48-2922
Model 2224-1	48-2748	Model 43-37-1	Active: 821 cm² (127 in²) Open: 609 cm² (94.4 in²)	2.5 x 15.9 x 64.1 cm (1 x 6.25 x 18.25 in.)

Specifications

Indicated Use	Floor monitoring for alpha, beta, and gamma
Detector	Gas proportional
Recommended Counting Gas	P-10 (10% methane; 90% argon)
Cylinder Size (D x H)	Will hold a cylinder 15.2 cm x 48.3 cm (6 x 19 in.) or smaller (Linde size “Q”, Matheson size 3, Airgas size “R”)
Window	0.8 mg/cm² aluminized Mylar (window thicknesses of 0.4, 3.9, or 7.9 mg/cm²are available). See configuration table for active and open areas.
Efficiency	²³⁹Pu: 17% ⁹⁰Sr/⁹⁰Y: 25% Gamma: < 1%
Gas Recharge	Will operate on static charge for 2 hours
Detector Height	Adjustable from 0.32 to 7.6 cm (0.125 to 3 in.) from surface
Detector Operating Voltage	Alpha: Typically 1000 to 1200 V Beta-Gamma: Typically 1600 to 1800 V
Threshold	Typically 2 to 4 mV
Flow Meter	In: Adjustable from 0 to 100 cc/min Out: Flow indicator from 0 to 100 cc/min
Gas Connectors	Double-end quick disconnect for 0.6 cm (0.25 in.) OD tubing
Gas Consumption	Typically 50 cc/min
Construction	Detector: Anodized aluminum housing with stainless steel hex protective screen (79% open) Cart: 2.5 cm (1 in.) square tubular steel and aluminum with beige powder coat paint, 19.1 cm (7.5 in.) diameter rear wheels, and 10.2 cm (4 in.) diameter swivel casters
Cart Assembly (H x W x L)	106.7 x 40.6 x 69.9 cm (42 x 16 x 27.5 in.) (excluding detector)
Weight	11.4 kg (25 lb), excluding gas bottle and counting instrument

Options

Option	Description	Part Number
Model 2750	Gas flow control box	48-2146
2-Stage Gas Regulator	Gas regulator	2310017
Model T-1031	Gas flow time control	48-2472

Description	Part Number
Model 43-37 Gas Proportional Detector	47-1143
Model 43-37 Window Assembly	4304-017