1. Familiarization and Operation
Ludlum RK
Familiarization and Operation

2. Ludlum 2241-2 Response Kit Contains: 2241-2 and check source
                                          
Contains:
and check source
44-2 gamma probe
44-9 pancake probe
Cable, batteries
Manuals

3. Ludlum
The Model is a portable microprocessor-based digital Scaler/Ratemeter designed for use with a variety of detector types for measurement of ionizing radiation. 
Side mounted check source

4. Model 44-2 Gamma Probe Very sensitive to Gamma radiation
Uses a 1”x1” crystal (NaI)
Not rugged – but Not delicate
Intended to search for radiation

5. Model 44-9 (Pancake) Probe
Detects Alpha, Beta, Gamma, & X-ray
Gas Tube covered by thin Mica window
For use when surveying for contamination

6. Accessories
Cable
Batteries (may be removed for storage)
Manuals
Case

7. Ludlum 2241-2 3 position selector switch Locking toggle probe switch
Off/Ratemeter/Scaler
Locking toggle probe switch
Audio on/off switch
Fast/Slow response switch
Light button
Reset button
Off/Ratemeter/Scaler Switch: A three-position rotary switch which applies power to the instrument and selects the RATEMETER or SCALER counting modes.
DETector Select Switch:  A protected toggle switch that toggles between DET 1 and DET 2 parameters.   The pull-and-change toggle switch is designed to protect against inadvertent changes.  The switch is to be set to DET 1 when the pancake probe  is attached; units displayed will be KCpm.  Set the switch to DET 2 when the hotdog probe is attached; units displayed will auto range from uR/hr to mR/hr to R/hr.
AUD ON/OFF Switch:  The audio may be silenced or enabled via this toggle switch.  The audible ALARM is independent of the AUD ON/OFF switch.
F/S (Fast/Slow) Response Switch:  A two position toggle switch with selects Fast or Slow counting response time.  The fast response setting should be used when performing an initial survey or when trying to locate sources of radiation.  Switch to slow response when more accurate measurements are needed ( e.g. for official measurements).
Light (LCD Backlight):  A pushbutton switch, when depressed, illuminates the LCD for a pre-programmed period of time.
RESET Pushbutton Switch:  In the non-alarm condition, depressing the RESET switch resets the Ratemeter display to the minimum display readout.  In an alarm condition, depressing the RESET will silence the audible alarm; depressing the RESET Switch a second time will reset the Ratemeter alarm and/or alert condition.   The Scaler alarm can only be reset by depressing the Scaler to start the counting cycle.  Scaling time is set during instrument calibration and can be set from 1 to 999 seconds.  Depressing the Count switch after a Scaler ALARM will reset the Scaler display to "0" resetting the alarm condition.

8. 2241-2 Display LCD 4-Digit display Floating decimal point
Auto ranging from uR/hr to mR/hr to R/hr
(KCpm to Cpm as well)

9. Display (cont)
Overflow – “OFLOW” indicates the incoming count of exposure exceeds the capability to display stable or reliable readings.
Alert – shows at 20 KCpm or 20 uR/hr
Alarm – shows and sounds at 50 KCpm or 50 uR/hr
Overflow indicates the count rate exceeds one million counts.

10. Display (cont)
Overload – Indicates the detector is being exposed to radiation intensities greater than the detector maximum operating limit, and/or the mica window has been damaged.
Counting – Indicates the Scaler count switch has been depressed and the Scaler is accumulating counts for the pre-determined count time.

11. Operating Instructions
Safety – Always switch into “OFF” position before connecting or disconnecting the cable or detector.
Install Batteries - Open the battery lid and install two "D" size batteries.  Note (+) (-) marks on the inside of the lid.  Match the battery polarity to these marks.  Close the battery box lid.
Connecting Probes – Select “Det 1” or “Det 2”. Connect the probe (Det 1 = 44-9, Det 2 = 44-2 they are color coded as well). Connect one end of the cable provided to the detector by firmly pushing the connectors together while twisting clockwise ¼ turn until it latches

12. Operating Instructions (cont)
Place Audio switch into off position
Place F/S switch into Fast position
Double check your detector switch position

13. Operating Instructions (cont)
Power on – Turn selector switch clockwise to ‘Ratemeter” setting. The meter will cycle through its startup routine and display will show
All indications
Program version
Detector channel selected
Go to Ratemeter mode

14. Operating Instructions (cont)
Battery low indication will blink if batteries are low.
Operational check – Place gamma probe/pancake probe directly on the check source and observe readings greater than 250 uR/hr. You can also check the calibration readings on the calibration record.

15. Operating Instructions (cont)
Check the unit’s response:
Place the probe next to the source – the indications should increase and stabilize
Pull the probe away from the source and the indications should decrease, slowly return to the source and the indications should rise up again.
Place the F/S switch to SLOW. Remove and replace the probe. Response times should be significantly slower.
Place the audio switch into the ON position – the audible should corresponded to the display readings.
The unit is ready for use.

16. Scaler Operations
The has a Scaler function to assist in detecting low levels of radiation.
Operating in the Scaler mode.
Place audio in the OFF position
Place the OFF/Ratemeter/Scaler 3 position switch in the SCALER position.
Place the probe face close to the item to be counted (both probes 44-2 and 44-9 can be in Scaler mode)
Press the Scaler start button in the handle. The word “Counting” will appear in the display.

17. Scaler Operations (Cont)
Operating in the Scaler mode (Continued).
The will begin a 12 second count cycle.
At the end of the 12 seconds the word Counting will disappear and the total for the count will be displayed.
Place the OFF/Ratemeter/Scaler 3 position switch in the Ratemeter position to begin surveys again.

18. Alert and Alarm
When the probe detects radiation in levels that exceed the alert level the word ALERT will appear in the screen.
Remove the probe from near the radiation and press the reset button. The count will reset to zero and the Alert will go away
When indications exceed the alarm level the word ALARM will appear in the window and an audible alert will sound
Remove the unit from near the source and press reset once. This will quiet the audible alarm. Note: the alarm will sound even if the speaker is turned off.
Press the reset a second time and it will reset the count and ALARM will go away.

19. Using the Ludlum 2241
Take a background reading before surveying for radiation
Three times above background is radiation
With the 44-2 Gamma probe use a “Stately Pace” and point the detector at the area to survey
With the 44-9 use the red plastic cover to protect the mica surface. You can also use it when you use the 44-9 for gamma surveys. (alphas and betas will be blocked)

20. Using the Ludlum 2241 (cont)
Place the 44-9 pancake head about ¼ to ½ an inch above the surface surveyed.
Survey at 1 inch per second with the 44-9
Be careful when handling the connector cable as it can provide an uncomfortable shock.

21. Using the Ludlum 2241 (cont)
The audio on position consumes batteries faster than when set to off
Use the Fast position for general surveys and the Slow position for low level surveys

22. Recommendations
DO NOT leave the batteries in the unit if you do not intend to use it.
Give the unit 5-10 seconds to stabilize once you have turned it on.
Do not get water on the mica window. Wrap it in a plastic bag (for gammas) Also works to prevent contamination.
Store where you would be comfortable, no temperature extremes

23. Questions

24. Contact Info
Bill Potter
Governor’s Office of Emergency Services
Radiological Preparedness Unit
(916)