Abstract: An Integrated Superconductor Sampling Oscilloscope may include a sampling gate utilizing superconductor devices such as a Josephson junction device as well as external circuitry for producing a visual representation of an input signal responsive to the output of the sampling gate. The oscilloscope may further comprise an attenuator for receiving the input signal, a trigger recognizer comprising superconductor devices which produces a pulse signal when the input signal from the attenuator exceeds a threshold level, a hold-off gate which produces an output signal when the pulse signal from the trigger recognizer is produced concurrently with a gating event, and electrical variable delay which may comprise superconducting devices and produces a delayed pulse signal in response to an output signal by the hold-off gate and a strobe pulse generator which produces a signal to the sampling gate in response to the pulse signal from the electrical variable delay output.

Abstract: A system for delivering a cryogenic fluid to cool devices, such as electronic devices, in an open-cycle environment. The system comprises a dewar which stores a cold fluid, a cryogenic module for holding a device to be cooled and a cold fluid transfer line which delivers the cold fluid from the dewar to the device within the cryogenic module. The system further comprises an interlock mechanism to hold the transfer line and the dewar securely together and a coupling mechanism to allow the transfer line to securely engage the cryogenic module. The system also comprises a control subsystem which monitors and controls the flow of cold fluid from the dewar and through the transfer line.

Abstract: An improved open-cycle cooling apparatus in which a cooling chamber holding a device to be cooled is coupled with a cold fluid delivery system and, in which the cold fluid delivery system includes a delivery tube which directs a stream of cold fluid to strike the device and a return which vents the expended cold fluid from the cooling chamber. The improvement comprises a rigid enclosure formed within the chamber and configured to adaptively engage one end of the cold fluid delivery tube. The device to be cooled is disposed within the enclosure. The enclosure also includes a return to remove expended cold fluid from the cooling chamber to the return of the cold fluid delivery stystem. The improvement further comprises an alignment guide disposed within the enclosure between the device to be cooled and the one end of the cold fluid delivery tube engaged to the enclosure.

Abstract: A circuit element for a superconducting integrated circuit is disclosed which comprises a plurality of Josephson junctions stacked vertically atop one another. Such a circuit element is capable of replacing single junctions and lateral arrays of junctions in many analog and digital applications. When operated digitally, the close proximity of the junctions to one another creates a "tight coupling" effect which permits the entire stack to switch as a single junction. Input (control) currents and output (bias) currents can be injected or taken out at any level or levels in the stack, thereby permitting excellent isolation, voltage gain, and the use of a single stack as a combination logic element. The use of tight coupling is extendable to lateral arrays as well. A method by which a circuit including vertical tunnel junctions may be fabricated is also disclosed.

Abstract: An apparatus and method for measurement of a signal with a monitor gate is disclosed. A signal to be measured is applied as an input to the monitor gate and a detection signal is generated that indicates whether or not the monitor gate has switched between states. A digital output is generated that corresponds to the integration of the detection signal. The output of the digital integrator is applied to a digital-to-analog converter. The output of the digital-to-analog converter is fed back to the monitor gate. A probability limit monitor and a gain control with respect to signal measurement are also disclosed.

Abstract: An apparatus for measuring the intensity of incident optical radiation utilizes the properties of superconductivity films. The apparatus may include at least one Josephson junction having the optical radiation incident thereupon, an electronic circuit coupled to receive a signal from the Josephson junction proportional to the incident radiation. The Josephson junction has a time-current switching threshold current selected to switch the function 50% of the time. A feedback loop from the electronic circuit maintains the function operation. One or more junctions may be used to monitor radiation of different wavelengths or to produce optical images.

Abstract: An incremental time delay generator may be disposed on a small substrate and may be used in conjunction with a time domain reflectometer. The incremental time delay generator produces an output signal at a variable time delay in response to a trigger signal and it may include a first superconducting device for generating a first pulse signal in response to the trigger signal, a transmission line configuration or a multiple inductive tap device for converting the pulse signal into a step signal wherein a time interval T is defined as the time between successive steps of the step signal; and a second superconducting device that is responsive to the step signal and produces a second pulse signal when the step signal exceeds a predetermined threshold. The time delay generated by the generator is equal to nT when the step signal exceeds the predetermined threshold in the (n+1)th step of the step signal.

Abstract: A monolithic chip is described which is suited for a superconductive device. The chip includes a substrate with high and low temperature region, a superconductive device formed on the low temperature region and various lines for transmitting signals between the device and the high temperature region. Various configurations are described for optional separation of the high and low temperature region as well as high and low bandwidth signal lines. Chips with various geometric substrates are also described.

Abstract: A device to measure the extremely fast electrical waveform generated when atomic or subatomic particles of an identical type strike an electronic circuit or device. The device comprises a trigger element which signals the incidence of a particle on the electronic device and a picosecond sampler which receives the trigger signal and the waveform generated by the electronic device. The sampler obtains a measurement of a discrete point on the generated waveform each time a particle passes through the trigger element to the electronic device. The sampling point on the waveform can be moved by various techniques so that the entire waveform may be measured by the sampler.

Abstract: Apparatus is disclosed for electrically interfacing a circuit operable at one temperature with a circuit operable at another temperature, comprising a primary cooling or heating surface disposed inside a vacuum chamber which is thermally connected to the first circuit. Transmission lines may extend through the wall of the vacuum chamber to the second circuit which can be located outside. In one embodiment, the first circuit is operable at cryogenic temperatures and is fabricated on an elongated fused quartz substrate together with the transmission lines. The first circuit may be thermally connected to the primary surface via a secondary surface, which may itself be thermally connected to the primary surface via a flexible support and/or a thermal switch. The use of a flexible element in the construction of the apparatus prevents thermally induced movement from shattering the substrate.

Abstract: Apparatus and a method are disclosed for cooling a low temperature circuit substrate without the need for a vacuum chamber or total immersion, involving subjecting the circuit to a stream of cold fluid, such as liquid helium, and allowing the fluid thereafter to dissipate into the surrounding environment. The apparatus may include an enclosure for holding the circuit, and means for guiding the fluid onto another portion of the substrate after it strikes the circuit. The exit path for the fluid may fold back past the circuit so as to help convect out heat which enters the vicinity radially from the outside. The circuit may also be cooled indirectly by directing the stream of cold fluid through a thermally conductive block, the block having a small surface thermally connectable to the circuit. Additionally, radiation shields may be placed at desired locations in the apparatus and can be cooled by the waste fluid after it cools the circuit.