Model 25 Series

Personal radiation monitor

A compact, rugged monitor that warns response personnel of elevated radiation fields.

Detector type: Internal energy-compensated GM1
Energy range: 60 keV–2 MeV1
Weight including batteries: 144 g1

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

Key features

Portable personal instrument.
Audible and visual indication.
For emergency response and radiation protection.

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

Detector type	Internal energy-compensated GM1

Measuring range

Energy range	60 keV–2 MeV1
Calibrated exposure-rate range	Model 25: 2 mR/hr–999 R/hr2
Calibrated dose-rate range	Model 25-1: 0.02 mSv/h–9.99 Sv/h2
Accumulated exposure	Model 25: 0–999 R2

Connectivity & interface

Display	Backlit LCD, 3½ digits1

Power & battery

Power supply	2 lithium coin cells1
Battery life, typical	6000 h1

Mechanical

Dimensions (H × W × L)	7.6 × 5.4 × 1.7 cm1

Environment & ratings

IP rating	IP671
Operating temperature	−40 to +65 °C1

Ordering & accessories

Weight including batteries	144 g1

General

Indication	Audible and visual; adjustable alarms1

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 25 Series Personal Radiation Monitor (data sheet)Datasheet · 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 25 Series Personal Radiation Monitor (data sheet)
Publisher: Ludlum MeasurementsDatasheet p. 1, Specifications; p. 1, Features and Specifications (ALERTS & ALARMS) Checked 2026-10-16
2
Model 25 Series Personal Radiation Monitor
Publisher: Ludlum MeasurementsProduct page Specifications tab (Calibrated Range); Features (Accumulated Dose Range) Checked 2026-10-16