Ludlum Model 239-1F with Model 2221

  Floor Radiation Monitor

●  Alpha, Beta, Gamma Floor Radiation Monitor

●  425 cm² Gas Proportional Detector

●  Utilizes Ludlum Model 2221 Analog Ratemeter/Digital Scaler

●  Adjustable Detector Height

●  Efficiency: ²³⁹Pu - 17%, ⁹⁰Sr⁹⁰Y - 25%, Gamma < 1%

The Model 239-1F Floor Radiation Monitor is an alpha beta gamma radiation 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. This unit is supplied with the Model 12 Analog Radiation Survey Meter. Refer to the Model 2221 for additional detail.

PART NUMBER: 48-2085

ELECTRONICS: Ludlum Model 2221

APPLICATION: floor monitoring for alpha, beta, gamma radiation
RADIATION DETECTOR: gas proportional
RECOMMENDED COUNTING GAS: P-10 (10% methane; 90% argon)
CYLINDER SIZE: will hold a cylinder 6 x 19 in. (15.2 cm x 48.3 cm) (Dia x H) 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/cm² are available)
ACTIVE AREA: 584 cm²
OPEN AREA: 425 cm²
EFFICIENCY (4π): 17%-²³⁹Pu; 25%-⁹⁰Sr/⁹⁰Y; gamma < 1%
GAS RECHARGE: will operate on static charge for 2 hours
DETECTOR HEIGHT: adjustable from 0.125-3 in. (0.32-7.6 cm) from surface
DETECTOR OPERATING VOLTAGE:

Alpha: Typically 1000-1200 volts
Beta Gamma: Typically 1600-1800 volts

THRESHOLD: typically 2-4 mV
FLOW METER: IN - adjustable from 0-100 cc/min; OUT - flow indicator from 0-100 cc/min
GAS CONNECTORS: double end quick disconnect for 0.25 in. (0.6 cm) OD tubing
GAS CONSUMPTION: typically 50 cc/min
CONSTRUCTION:

Detector: anodized aluminum housing with stainless steel hex protective screen (79%open)
Cart: 1 in. (2.5 cm) square tubular steel and aluminum with beige powder coat paint, 7.5 in. (19.1 cm) diameter rear wheels, and 4 in. (10.2 cm) diameter swivel casters

DETECTOR SIZE: 0.8 x 6.3 x 18.3 in. (2 x 16 x 46.5 cm) (H x W x L)
CART ASSEMBLY: 42 x 16 x 27.5 in. (106.7 x 40.6 x 69.9 cm) (H x W x L) (excluding detector)
WEIGHT: 25 lb (11.4 kg), excluding gas bottle and counting instrument

CE CERTIFIED: yes

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