DOC; Mountain Administrative Support Center; Acquisition Management Division; 325 Broadway MC3; Boulder, CO

66 -- ULTRASONIC IMMERSION MEASUREMENT SYSTEM SOL NB8530803008MB POC Michelle Bernal, Purchasing Agent, (303) 497-3983 or FAX (303) 497-3163 E-MAIL: NOAA; MASC Acquisition Management, Michelle.A.Bernal@noaa.gov. The National Institute of Standards & Technology (NIST) requires a computerized immersion scanning system designed for high resolution ultrasonic measurements. The system should include a high accuracy bridge scanner with universal probe mounting fixtures, a large immersion tank (at least 900 x 600 x 300 mm), a high dynamic range pulser/receiver, a motion controller, and advanced Windows-based software. NIST will provide a computer capable of controlling the system. The system should provide acquisition, analysis, and digital signal processing capabilities for high fidelity RF waveforms. Data acquisition software and hardware must generate an external trigger to synchronize pulsers and other instrumentation, and simultaneously acquire data. The primary use will involve high precision time-of-flight and amplitude measurements. Rigorous design and innovative use of special materials must provide an underlying mechanical structure that is very rigid, stable over time, and resistant to changes in ambient temperature. All of these features should work together to yield an absolute positioning accuracy of at least 5 microns throughout a scanning envelope of at least 400 x 400 x 300 mm without compensation. Provisions should be made to provide 3 axes position feedback with 1.0 micron resolution and repeatability. The system should have an expansion capability to allow for additional rotational degrees of freedom in the future. It is desirable to have air bearings or similar features on all axes with roller friction drives free of recirculating balls and the characteristic oscillation and vibration they produce. In addition, linear DC motors and drives should provide motion that is free of electrical interference allowing a high level of RF gain during scans. It is desirable that the system be capable of operating with transducers of at least 100 MHz center frequency. Typically, the system operate in the 0.25-25 MHz region. Use of a square wave pulsar is required. Ability to high pass and low pass filter the received signals is required. Also, it is desired that the pulser exhibit a 50 ohm (resistive) output impedance, and the pulse amplitude should be adjustable over at least a 5:1 amplitude range. The open circuit pulse amplitude should be at least 300 volts, and the receiver should be linear over at least a 50 dB range. The system should provide superior performance in demanding, high resolution, ultrasound measurements. List of specifications as follows: Square wave pulser unit: 1)Rise time less than 2.0 ns; 2) Fall time less than 2.0 ns; 3) Load impedance 50 ohms; 4) Min. load impedance -- capacitive load to 10 amps; 5) Output voltage minimum 100 V; 6) Output voltage maximum 500 V; 7) Voltage increment 2V; 8) Pulse width minimum 5.0 ns; 9) Pulse width maximum 80 ns; 10) Pulse width resolution 0.20-0.50 ns; 11) Pulse width accuracy 10%; 12) PRF minimum 200 Hz; 13) PRF maximum 20 kHz. Receiver: 1) Bandwidth(-3dB) 1 to 150 MHz; 2) Equivalent input noise 100 microvolts peak to peak max; 3) Maximum output level0 dBm; 4) Output headroom 6 dB; 5) Voltage gain minimum 0 dB; 6) Voltage gain maximum 63 dB; 7) Gain increment 1 dB; 8) High pass filter 1 -- -20 MHz(in 1 MHz steps); 9) Low pass filter 20 -- 150 MHz(in 1 MHz steps). Digitizer (1 GHz/second sampling and at least 8 bits per sample, motion controller hardware/software, probe holder, cabling, windows based data acquisition software compatible with the system, and system capable of operating with transducers ranging between 0.25 MHz to at least 100 MHz center frequency. Unit should be delivered in no more than 6 weeks after receipt of order. There is no formal RFQ. Interested sources may submit a bid by fax or mail but it must be received on or before November 20, 1997. Technical merit as well as price will be used to evaluate offers. As the technical merit becomes more equal, price becomes a greater factor. Procurements under Simplified Acquisition Procedures ($100,000 or less) are set-aside for small business unless small business cannot meet the need ata reasonable price. (0310)

Loren Data Corp. http://www.ld.com (SYN# 0236 19971110\66-0014.SOL)