Model 3-IS

Intrinsically safe survey meter

An analog survey meter for radiation measurements in potentially explosive atmospheres when used with compatible Ludlum detectors.

Count rate, typical: 0–500 kcpm (detector dependent)1
Weight including batteries: 1.6 kg1

Download product sheet (PDF)All values with references – for tender documents

Specifications checked against the manufacturer’s documents on 2026-10-16

Manufacturer’s product page (opens in a new tab)

Overview

Nuclear power & nuclear technology Defence, security & preparedness Emergency services & first response Environmental monitoring & radiation protection Industry & quality control

Key features

Intrinsically safe design for selected approved probes.

Specifications

The number after each value refers to the source listed below. Values are as published by the manufacturer; the exact configuration is always confirmed in our quotation.

Detector

Compatible detectors	44-7, 44-9, 44-6, 44-38, 44-2, 42-41L1
Radiation (probe dependent)	Alpha, beta, gamma or neutrons2

Measuring range

Exposure-rate range, typical	0–200 mR/hr (detector dependent)1
Count rate, typical	0–500 kcpm (detector dependent)1
Response time (10–90%)	FAST 4 s; SLOW 22 s1

Electronics & signal

Detector bias	400–1000 V DC (adjustable)1

Connectivity & interface

Display	Analog; ×0.1, ×1, ×10, ×1001

Power & battery

Approved batteries	2 Procell PC1300, D, 1.5 V1
Battery life, typical	Over 2000 h (alkaline batteries)1

Mechanical

Dimensions (H × W × L)	16.5 × 8.9 × 21.6 cm including handle2

Environment & ratings

Operating temperature	−20 to +50 °C1
Intrinsic safety classification	Class I, Division 1, Groups A–D, T61

Ordering & accessories

Weight including batteries	1.6 kg1

The data comes from the manufacturer’s published documents. Manufacturers may change specifications; the current configuration and performance are confirmed in the quotation.

Documents

PDFModel 3-IS Series Intrinsically Safe Survey MetersDatasheet · Ludlum

Sources

The number after each value refers to the source listed below. Values are as published by the manufacturer; the exact configuration is always confirmed in our quotation.

1
Model 3-IS Series Intrinsically Safe Survey Meters
Publisher: Ludlum MeasurementsDatasheet p. 1, Model 3-IS column (Detector); p. 1, Common Specifications; p. 1, Model 3-IS column (Detector Range); p. 1, Common Specifications (RESPONSE) … Checked 2026-10-16
2
Model 3-IS Intrinsically Safe Survey Meter
Publisher: Ludlum MeasurementsProduct page Specifications tab (Application); Product page – Specifications Checked 2026-10-16