The QMC-JPA-MCA01 from Quantum Microwave is a Cryogenic Turn-key Assembly that has been developed to operate Raytheon BBN's 5 – 7 GHz Wide Bandwidth Josephson Parametric Amplifier (JPA). It can be used to design, develop, and validate auxiliary cryogenic circuitry which is required before near-quantum limited noise measurements can be conducted with the JPA. This assembly is fully characterized at < 20 mK before being shipped to determine tuning parameters for gain and noise. The cryogenic circuit of this assembly consists of a cryogenic Low Noise Factory circulator LNF-CIC4_8A, Quantum Microwave bias-Tee QMC-CRYOTEE-0.218SMA-FFF, Quantum Microwave LC/Infrared Eccosorb filter combination QMC-CLCE-160AFF, and Raytheon/BBN JPA #BBN-PS2-JPA-DEVICE-QEC.
The QMC-JPA-MCA01 is composed of a cryogenic circuit built around the JPA to facilitate its operation. It is based on a Superconducting Quantum Interference Device (SQUID) which is very sensitive to external magnetic fields. This assembly is magnetically shielded with a mu-metal can made from A4K proprietary alloy to minimize the impact of external magnetic field fluctuations in the environment. To minimize potential offsets in current bias tuning of the JPA or hysteretic effects, all components inside the mu-metal can are non-magnetic. In this assembly, the DC bias is filtered by the QMC-CLCE-160AFF filter which provides a cutoff frequency at 160 MHz. The filter is also encapsulated with Eccosorb infrared absorber which provides strong attenuation out to the infrared.
The QMC-JPA-MCA01 provides a gain of more than 20 dB with an instantaneous bandwidth of 300 MHz and has a noise temperature of 295 mK (at 6.8 GHz). It comes in a compact Aluminum cryo-package with a 50-ohm matched input and 2.92 mm input/output connectors. This assembly is designed to be installed onto the mixing chamber plate of a dilution refrigerator and is compatible with standard RF microwave readout chains found in cryogenic measurement setups used to characterize superconducting devices.
