LUDLUM 2241 Quick Start Manual

LUDLUM (2241) SURVEY METER

RATEMETER SET-UP

1. Turn OFF/RATEMETER/SCALER switch to [OFF] position.
2. Open battery lid (1/4-turn screw counterclockwise).
3. Install (2) "D"-sized batteries.
4. Close and lock battery lid (1/4-turn screw clockwise).
5. Set FAST/SLOW RESPONSE switch to [F] position.
6. Set AUD ON/OFF switch to [ON] position.
7. Connect pancake probe – OR- tubular probe to meter using the connection
cable.
 Push connectors together & ¼-turn clockwise to latch.

If using pancake probe, remove plastic protective cover.
8. Lift up and set DETECTOR SELECT SWITCH to proper position:

Pancake Probe: [DET 1] (red dot) position.

Tubular Probe: [DET 2] (yellow dot) position.
9. Turn OFF/SCALER/RATEMETER switch to [RATEMETER] position.
10. Wait 15-20 seconds for unit to warm up.
11. The instrument is ready for use. See "Checking Background Radiation".
Count has increased above the preset alarm threshold.
Audible continuous tone will activate with "ALARM".
"ALARM"
Press [RESET] x1 to acknowledge alarm.
Press [RESET] x2 to reset reading & alarm.
Ratemeter count has increased above preset alert threshold.
Press [RESET] x1 (non-alarm condition) to reset.
"ALERT"
Press [RESET] x2 (alarm condition) to reset..
Indicates incoming count exceeds capability to display stable/reliable
"OFLOW"
readings. ("Overflow")
Indicates detector exposed to radiation intensities greater than the
"OVERLOAD"
detector maximum operating limit.
Low battery Indicates batteries have decreased to minimum operating voltage
icon (∼ 24 run time remaining).
ALARM / ALERT SETTINGS
PANCAKE PROBE Rate Alarm: 50 kcpm, Rate Alert: 20 kcpm
TUBULAR PROBE Rate Alarm: 50 μR/hr, Rate Alert: 20 μR/hr
DELRAY BEACH FIRE-RESCUE DEPARTMENT
QUICK USER GUIDE
NOTES
 Portable alpha, beta, and gamma radiation survey meter that can measure radiation exposure,
contamination, and samples. Operates as a ratemeter or scaler (primarily used as a ratemeter).

Technology: Portable microprocessor-based digital scaler/ ratemeter . Scintillation (tubular
probe) detector and Geiger-Mueller (pancake probe) detector.

Power Source: Disposable "D"-sized batteries (x2).
Approximately 200-hrs run time. Not instrinsically safe.
o
 (2) Operating Modes:
Ratemeter – provides the real-time indication of the radiation rate (dose rate).
o
Scaler – totalizes number of counts over a 6-second period. Multiply by 10 to determine
o
counts-per-minute.
 Detector Probe Options:
Pancake Probe (Model 44-9): Halogen-quenched Geiger Muller radiation detector.
o



Tubular Probe (Model 44-2): Sodium iodide gamma scintillator detector.
o



 LCD digital display with moving decimal point. Display auto-ranging from [0.0 μR/hr – 9999
R/hr] or [0 CPM – 999 K CPM]. Backlight activated by pressing [LIGHT] button.

BASIC INSTRUMENT OPERATIONS

DISPLAY ICONS
Revised: 10/30/18

GENERAL INFORMATION

Application: Contamination surveying & sample measurements.
Detects: Alpha, beta, and gamma radiation.
Reads in Counts-per-minute (CPM).
Application: Background radiation monitoring and low-level radiation detection.
Detects: Low-level gamma radiation.
Reads in μR/hr, mR/hr, & R/hr.

RATEMETER OPERATIONAL CHECK

1. Open check source door (side of meter) & hold probe to the
check source.
 Pancake Probe: Mesh window side.

Tubular Probe: Flat end of probe, opposite the
connector.
2. Allow the meter to stabilize & check display reading. Display
reading should be within range listed on probe's calibration
sticker (see labels on the side of the instrument).
3. Remove probe from check source and close check source door.
4. Press [RESET] button to silence alarm and clear display
reading.

CHECKING BACKGROUND RADIATION

Perform background check in Cold Zone prior to making entry.
1. Hold probe at full length of connection cable.
2. Check display and make a note of re-entry background readings.
5-25 μR/hr
100 μR/hr
2 mR/hr
500 mR/hr
5 R
10 R
25 R
100 R
Verify – Reproduce alarm with another instrument.
Locate – Attempt to find the source causing the alarm.
Measure – Note the maximum radiation dose rate.
Minimize Time, Maximize Distance, Use Shielding
* Dose Rate: radiation dose delivered per hour
* Dose: amount of radiation absorbed by the body
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EXPOSURE ACTION GUIDELINES

Normal Background.
Actions: Verify – Locate – Measure – Notify
Exclsuion (HOT) Zone Boundary
Turn Back Now
Maximum Dose – Emergency Response
Maximum Dose – Property Preservation
Max Life Safety Dose w/ Informed Consent
Acute Radiation Exposure
ACTIONS
Notify – Advise supervisor of situation.
Personal Protection