The previous owner has replaced the standard bottom plate with an oversized aluminum plate. (see photos)
The front top hand screw on lid hole threads are stripped, the back one is fine.
The Acton Research Corporation (ARC) Model VM-503 is a 0.3-meter scanning vacuum monochromator optimized for the ultraviolet (UV) region. It uses a modified Czerny-Turner optical system and features an Al+MgF2 coated plane grating, commonly with 1200 grooves/mm, providing high performance below 200 nm.
Key Specifications & Features:
Model: Acton Research Corporation VM-503.
Type: 0.3-meter scanning vacuum monochromator.
Optical System: Modified Czerny-Turner.
Wavelength Range: Optimized for Vacuum UV (VUV) and UV, often used down to 120 nm with appropriate coatings.
Grating: Typically Al+MgF2 coated, 1200 grooves/mm (often blazed at 300 nm).
Resolution: Approximately 0.5 Å.
Operation: Computer-controlled stepper motor for wavelength scanning.
Applications: Suited for VUV spectroscopic applications, including sonoluminescence measurement.
The VM-503 is part of the Acton VM Series, which includes vacuum-compatible monochromators designed to operate in high-vacuum environments to avoid UV absorption