Model 9-3

Ion Chamber Survey Meter

Part Number: 48-3633

Features

5 Ranges from Background to 500 mSv/h (50 R/hr)
1000 mg/cm² Retractable Beta Shield
Temperature Compensated
Low Battery Warning
High Background Zero Capability
Proportional Audio Output
Adjustable Shoulder Strap Included

The Ludlum 9-3 ion chamber is a rugged air ionization chamber for performing beta-gamma dose rate measurements over a five-decade span ranging from background to 500 mSv/h (50 R/hr). The chamber wall (including the instrument case) is 1000 mg/cm². A 1000 mg/cm² retractable beta shield allows beta measurement with a 7 mg/cm² window. The six-position switch selects Off, x10k, x1k, x100, x10 and x1. Each range has a front-panel mounted calibration control. Other features include an audio output, reset, and zero adjust capabilities. Means are also provided to zero the electrometer leakage current.

An adjustable shoulder strap (included) provides a convenient and comfortable mode to carry the instrument during surveys.

Specifications

Detection Range	0.002 to 500 mSv/h (0.2 to 50,000 mR/hr) (typical)
Energy Response	Within 20% of true value from 40 keV to 2 MeV
Linearity	Reading within 10% of true value
Window	7 mg/cm² metalized polyester; with slide open, allows gamma detection to 6 keV
Window Area	40 cm² (6.2 in²) 31.5 cm² (4.9 in²) open with optional 79% open screen
Chamber Volume	220 cm³ (13.4 in³)
Chamber Construction	Carbon coated acrylic
Side Wall	1000 mg/cm² aluminum and acrylic
Beta Shield	Retractable 1000 mg/cm² phenolic slide BETA FACTOR with the instrument exposed to a depleted uranium slab of 234 mrad/hr: Reading with slide Open: 50 mR/hr Reading with slide Closed: 1.2 mR/hr Beta Factor = 234 ÷ (50 - 1.2) = 4.8
Meter Dial	0 - 5 mR/hr, BAT TEST (Meter Faces tab lists other available meter faces)
Meter	6.4 cm (2.5 in.) arc, 1 mA, pivot-and-jewel suspension
Controls	Range Selection: x1, x10, x100, x1k, x10k, plus instrument off Reset: The RESET circuit grounds the chamber and opens the chamber connection to the electrometer. This causes a hard upscale transient on the x1 scale. Hold the RESET down for 4 s to allow the transient to decay. When the RESET switch is opened, the chamber is reconnected to the electrometer and a hard downscale transient will occur. Allow 20 s for recovery. Zero Adjust: Allows limited background subtract and an external one-turn potentiometer, and also used to compensate electrometer drift Battery: Push button used to check battery capacity Audio: On/Off Calibration: Individual potentiometers for each range; accessible from the front cover while in operational status
Response Time	Approximately 5 s for 90% of final meter deflection on the x1 and x10 scales, and 2 s on the x100, x1k, and x10k scales
Audio	Built-in unimorph speaker with ON/OFF switch
Temperature Range	-20 to 50 °C (-4 to 122 °F), temperature compensation maintains calibration within 15% of 25 °C reading
Power	2 each “AA” cell batteries housed in a sealed externally-accessible compartment
Battery Life (without display light)	1050 hours with x100 and higher ranges at full scale 1500 hours at x1 and x10 in low background
Construction	Cast and drawn aluminum with beige powder coating
Size (H x W x L)	23.4 x 8.9 x 21.6 cm (9.2 x 3.5 x 8.5 in.), including instrument handle
Weight	1.6 kg (3.6 lb), including batteries

Meter Faces

This table lists the most commonly used meter faces. Others are available upon request.

Meter Face	Image (click to view larger)	Description
202-1127		0 - 5 mR/hr BAT TEST
202-1137		0 - 50 µSv/h BAT TEST

Options

Option	Description	Part Number
Lighted Handle	Handle with LED to illuminate the instrument display.	4464-154
Transport & Storage Case - Medium	Rugged, dust- and waterproof transport and storage case.	2311063
Plastic Disk Check Sources	General purpose check sources used to check instrument response.	Depends on source material and activity.