Product Overview
Ortec 785 NIM Auto Fill Controller for HPGe Detector Cryostats - LN2 Level Monitoring and Automated Refill
Condition
Used, sourced from a government research facility. The unit shows scuffs and scratches consistent with lab service - nothing out of the ordinary. Evaluation: Visual inspection only. Function testing not performed. Front panel markings, display, LEDs, switches, BNC connectors, and DIP switch arrays are all present and intact per inspection. Module only - no accessories, cables, or documentation included.
Carefully packed and shipped same or next business day from our Idaho warehouse. Honest equipment and straightforward service.
Online since 1999. We are here for our customers, with a no-hassle satisfaction guarantee.
Product Overview
The EG&G Ortec 785 is a NIM-standard liquid nitrogen auto fill controller designed to automate LN2 replenishment in detector cryostats - most commonly those housing high-purity germanium (HPGe) detectors used in gamma spectroscopy. It mounts in a standard NIM bin, draws power from the bin backplane, and handles the monitoring and refill cycle without continuous operator attention. The front panel carries a red numeric display, alarm indicators, an ALARM RESET button, NORM/INHB and SOLENOID ON/OFF toggles, SHUTDOWN and LOW BAT warning LEDs, a SENSOR ADJUST trimmer, BCD-encoded DIP switch arrays for setpoint configuration, and BNC connectors on the right edge. A USE/SHIP toggle is also present. Port labels A, B, and C are visible on the lower panel section alongside SENSE INHIBIT, FILLING, EXPAND, and REM FILL indicators.
Key Features
- NIM-standard single-width module - mounts in any compliant NIM bin
- Automated LN2 level monitoring and refill triggering when levels drop below setpoint
- Solenoid control for LN2 flow from supply dewar to cryostat
- Safety shutdown to prevent cryostat overfilling
- ALARM RESET button and audible/visual alarm indicators for fault conditions
- SHUTDOWN and LOW BAT warning indicators visible on front panel
- BCD-encoded DIP switch setpoint configuration - MOST SIG DIGIT labeling confirmed on panel
- SENSOR ADJUST trimmer for sensor calibration
- NORM/INHB toggle for sensor inhibit mode
- Red numeric display for level or status readout
- BNC connectors for remote fill and sensor interface
- USE/SHIP toggle for transport safety
Applications
- Maintaining continuous LN2 cooling during multi-day gamma spectroscopy runs where manual refilling would interrupt data collection or introduce thermal drift into the HPGe detector
- Keeping HPGe cryostats filled in remote or access-restricted monitoring installations where regular technician visits for manual refilling are impractical or increase personnel exposure
- Replacing a failed or aging LN2 auto fill controller in an existing NIM-based detector system to restore automated operation without reconfiguring the rack
- Supporting nuclear power, waste management, or environmental monitoring labs that depend on HPGe detector uptime for compliance measurements
- Reducing hands-on time for research lab technicians running long-duration experiments requiring stable, uninterrupted detector cooling
Frequently Asked Questions
Does this require a specific NIM bin, or will it work in any standard NIM bin?
The 785 is a standard NIM-format module and is designed to mount and receive power from any compliant NIM bin. Verify that your bin provides the power rails the module requires before installing.
What else is needed to put this into service?
You will need a standard NIM bin, an LN2 supply dewar, a compatible detector cryostat requiring LN2 cooling, and appropriate interface cabling. The module alone does not constitute a complete cooling system.
Is this compatible with electrically cooled HPGe detectors?
No. The 785 is designed specifically for liquid nitrogen cooled cryostats. Electrically cooled HPGe systems do not use LN2 and have no use for this controller.
Has this been function tested?
Evaluation was visual inspection only. Function testing was not performed. The unit was marked as functional before being placed in storage at the government research facility where it was sourced.
Are a manual or interface cables included?
Not included.
HPGe detectors are unforgiving about LN2 gaps - a warm detector can mean weeks of recovery time and compromised data. An 785 that keeps the fill cycle running quietly in the background is the kind of infrastructure that lets the science happen on schedule.
