Model 30-7 Neutron Meter

³He proportional detector

Ludlum Measurements

• Neutron Dose Rate & Under 4.5 kg (10 lb)
  
• Adjustable Viewing Angle for Display Unit
  
• Moderated Neutron Detector
  
• Range: 0–100 mSv/h (0–10,000 mrem/hr)
  
• Display Unit Detaches for Greater Versatility
  
• Low-Weight Unit Provides Same Readings as Standard REM-ball from Bare AmBe and Lower Energies
  
• Includes Adjustable Shoulder Strap

The Model 30-7 Series are handheld, lightweight neutron dose detectors that joins the Model 30 digital meter with a 19.5 cm (7.7 in) diameter REM ball containing a ³ He detector. The instruments use similar detectors that only differ by the boron concentration in the internal borated layer. The Model 30-7 detector has a lower boron concentration and offers a greater sensitivity, typically 10 cpm per µSv/h (100 cpm per mrem/hr), but tends to overrespond in the 5 keV range. The Model 30-7B detector has a higher boron concentration and a lower sensitivity, typically 4.5 cpm per μSv/h (45 cpm per mrem/hr), but does not have the same overresponse issue as the Model 30-7.

Three modes of operation – RATE, MAX, and COUNT – are available for the user. Measurements can be collected in two sets of units (primary and secondary) for RATE and MAX modes in cps, cpm, rem/hr, or Sv/h units. An internal switch is used to enable or disable the front-panel setup feature to protect desired settings from inadvertent modification. Setup is also available via the Lumic calibration software (see Options tab).

Each instrument features a large, easily-readable LCD (liquid crystal display) that may be rotated for maximum ease of use by the operator. The connecting cable is threaded through the rugged carrying handle to simplify use. In addition, the display unit may be detached from REM ball, permitting the operator to position the detector and the display unit to best advantage within the limits of the cable length. Other features are an audio warning tone and easy, intuitive, user-friendly design. Splash-resistant construction allows the Model 30-7 Series to be used in outdoor environments. The display body is constructed of lightweight, durable, high-impact plastic.

Specifications

Indicated Use Neutron dose rate
Detector 3He proportional detector, 1.6 x 2.5 cm (0.6 x 1.0 in.) (D x L), surrounded by a 19.5 cm (7.7 in.) diameter polyethylene sphere with internal borated layer
Measurement Range 0 to 99.9 mSv/h (0 to 9.99 rem/hr)
Sensitivity (bare AmBe neutrons)
Model 30-7: Typically 10 cpm per μSv/h (100 cpm per mrem/hr)
Model 30-7B: Typically 4.5 cpm per μSv/h (45 cpm per mrem/hr)
Energy Response Provides approximate inverse RPG curve for neutrons from thermal through 7 MeV, provides response up to 12 MeV (see Energy Response Curve on Graphs tab). Model 30-7 tends to overrespond in the 5 keV range.
Linearity Reading within 10% of actual value
Gamma Rejection (137-Cs gamma) < 10 cpm through 0.1 Sv/hr (10 R/hr)
LCD Display 3 digit LCD with large 13.4 mm (0.53 in.) digits, low-battery indicator, MAX, ALARM, MUTE Units: (k)cps, (k)cpm, (µ)(m)Sv(/h), (µ)(m)rem(/h)
Display Range

• 0.0 cps to 99.9 kcps
• 0.00 cpm to 999 kcpm
• 0.00 µSv/h to 999 Sv/h
• 0.00 rem/hr to 999 rem/hr

Display range can be set to limit display to calibrated range
Backlight Built-in ambient light sensor automatically activates low-power LED backlight, unless internal dipswitch is set to continuous-On (will reduce battery life). Alarm light intensity varies based on ambient light levels.
Controls

• ON/OFF/ACK: Press to turn ON; Tap to acknowledge alarms and silence alarm tone; Press to reset Sigma Audio alarm, turn “click” audio On/Off, turn Sigma Audio beep On/Off; Press and hold for OFF
• UNITS: Changes the units between count rate (cpm, cps) or dose/exposure (µSv/h, rem/hr)
• MODE: Alternates between NORMAL (count rate), MAX (captures peak rate), and COUNT (user-selectable preset count time from 0 to 10 minutes). Number of modes can be reduced in setup.

Response Time User-selectable from 1 to 60 seconds, or Auto-Response Rate FAST or SLOW
Alarms Count rate, exposure/dose, and scaler alarm setpoints adjustable over the display range
Overload High count rate saturation protection prevents false display of lower count rates
Zero Protection After a user-settable time interval (default 60 seconds) of no pulses from the detector, the instrument will flash zero reading and the alarm audio will be triggered
Dead Time Correction Employs first and second order corrections for extended performance
Operating Voltage Approximately 1200 Vdc
Threshold -2 mV
Audio Greater than 75 dB at 0.6 (2 ft), approximately 4 kHz
Power Two alkaline or two rechargeable “AAA” batteries
Battery Life Approximately 100 hours of operation, 24-hour low battery warning
Construction High-impact plastic with water-resistant rubber seals and separate battery compartment
Working Environment Splashproof shields for outdoor use
Temperature Range -20 to 50 °C (-5 to 122 °F)
May be certified for operation from -40 to 65 °C (-40 to 150 °F)
Environmental Rating NEMA rating of 3x or IP rating of 52 with audio hole seal option (hole seal option will reduce maximum volume by approximately 10 dB)
Size
Display Unit: 8.5 x 8.0 x 4.8 cm (3.4 x 3.1 x 1.9 in.) (H x W x L)
Detector: 19.5 cm (7.7 in.) diameter REM ball with 3He detector (1.6 x 2.5 cm) (D x L)
Weight
Display Unit: 174 g (0.38 lb)
Detector: 4.6 kg (10.2 lb)