MRD 31 August 2026.docx

Minimum Requirements Document

Title: Alpha-Beta Gas Proportional Counting System Document Date: 21 August 2026 Scope: Vendor shall supply one (1) automated “Heavily Shielded Ultra-Low Background Gas Flow alpha/Beta Counters” Model G5020/100T to replace an existing system at the end of its service life.

Background: This instrument is used for the analysis of alpha and beta emitting nuclides via gas flow proportional counting.

Requirement/Salient Characteristics: Gas flow proportional counter must possess the following characteristics:

· Must allow trade in of older unit and pick up/remove older unit and credit AF on purchase of new units.

· Must come with a computer that runs on windows 10 or 11.

· System shall operate with standard P-10 counting gas.

· The system shall have 4” of lead shielding in all directions, tightly wrapped and with minimal openings. All components and materials are selected for minimum background contribution.

· System detector shall be 2-1/4” diameter, dual wire gas flow type with a separate gas flow guard detector operated in anti-coincidence mode for background reduction.

· Detector shall have an ultra thin gold plated Mylar window.

· The system shall have a automated sample changer [100 samples] with supporting software to allow unattended operation implementing user defined count sequences, user defined protocols that allow individual count times and reporting formats. The sample changer mechanism shall accommodate planchets from 1/8” to 5/16” depth with easy mix and match.

· The sample change mechanism shall be a true random access that minimizes sample movement when doing custom sequences.

· The sample change mechanism shall have multiple removable cartridges that can be remotely and individually loaded while the machine is processing other cartridges.

· System shall meet these performance measures:

· >99% cosmic rejection

· Beta background <1.3cpm

· Sr-90 efficiency >45%

· Po-210 efficiency > 35%

· Efficiencies are measured with a point source in close geometry

· Count data shall be accumulated multi-channel spectra, with a/B separation done with broad ROI’s. This makes set up and troubleshooting much easier. An MCA display function shall be provided.

· The HV supply shall have an automatic cutoff function in the case of low supply gas pressure.

· The HV shall be under computer control and user settable. The HV supply will have a hardware limit to protect against accidental over voltage.

· Software (format)

· Operating and control software shall be a MS-windows native application that runs on Win 7 thru 10. The system software shall not restrict standard windows networking or peripherals.

· System Software features shall include:

· Interactive menu driven operation

· User defined sample “type” counting protocols

· Automatic HV Plateau generation

· Chi-Square test and system diagnostics

· Multi-channel accumulation & display of a/B spectrum

· User selectable reporting units and formats (variable per sample type)

· Automatic background subtraction

· Counting parameters and sample results data stored in user accessible database format

· Report templates allow printing or regenerating sample result printouts

· Customer tailored printouts may be created

· Basic Control Chart QA Reports