We describe the status of the NIST Quantum Communication Testbed (QCT) facility. QCT is a facility for exploring quantum communication in an environment similar to that projected for early commercial implementations: quantum cryptographic key exchange on a gigabit/second free-space optical (FSO) channel. Its purpose is to provide an open platform for testing and validating performance in the application, network, and physical layers of quantum communications systems. The channel uses modified commercial FSO equipment to link two buildings on the Gaithersburg, MD campus of the National Institute of Standards and Technology (NIST), separated by approximately 600 meters. At the time of writing, QCT is under construction; it will eventually be made available to the research community as a user facility. This paper presents the basic design considerations underlying QCT, and reports the status of the project.
The performance of the Resonance Ionization Mass Spectrometry (RIMS) system at the National Institute of Standards and Technology (NIST) has been compared to a similar system at Pacific Northwest National Laboratory (PNNL). Efficiency and selectivity measurements were performed with both systems and compared to conventional thermal ionization mass spectrometry (TIMS). Determination of the <SUP>135</SUP>Cs / <SUP>137</SUP>Cs ratio was performed using single-resonance excitation 6s <SUP>2</SUP>S<SUB>1/2</SUB> (F equals 4) to 6p <SUP>2</SUP>P<SUB>3/2</SUB> (F equals 5) with an extended cavity diode laser followed by photoionization with the 488 nm line of an argon ion laser. Optical selectivity of more than 2 orders of magnitude against stable <SUP>133</SUP>Cs was attained for <SUP>135</SUP>Cs and <SUP>137</SUP>Cs for both systems with an overall selectivity of 10<SUP>9</SUP> for the PNNL system and 10<SUP>8</SUP> for the NIST system. Overall efficiencies of 2x10<SUP>-6</SUP> and 5x10<SUP>-7</SUP> were measured for the PNNL and NIST systems respectively. Measurements to determine the chronological age of a nuclear burn-up sample have been performed using both RIMS systems as well as TIMS.