3,036 research outputs found

    PHARAO Laser Source Flight Model: Design and Performances

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    In this paper, we describe the design and the main performances of the PHARAO laser source flight model. PHARAO is a laser cooled cesium clock specially designed for operation in space and the laser source is one of the main sub-systems. The flight model presented in this work is the first remote-controlled laser system designed for spaceborne cold atom manipulation. The main challenges arise from mechanical compatibility with space constraints, which impose a high level of compactness, a low electric power consumption, a wide range of operating temperature and a vacuum environment. We describe the main functions of the laser source and give an overview of the main technologies developed for this instrument. We present some results of the qualification process. The characteristics of the laser source flight model, and their impact on the clock performances, have been verified in operational conditions.Comment: Accepted for publication in Review of Scientific Instrument

    A study of Radiation-Tolerant Voltage-Controlled Oscillators designs in 65 nm bulk and 28 nm FDSOI CMOS technologies

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    Phase-locked loop (PLL) systems are widely employed in integrated circuits for space analog devices and communications systems that operate in radiation environments, where significant perturbations, especially in terms of phase noise, can be generated due to radiation particles. Among all the blocks that form a PLL system, previous research suggests the voltage-controlled oscillator (VCO) is one of the most critical components in terms of radiation tolerance and electric performance. Ring oscillators (ROs) and LC-tank VCOs have been commonly employed in high-performance PLLs. Nevertheless, both structures have drawbacks including a limited tuning range, high sensitivity to phase noise, limited radiation tolerance, and large design areas. In order to fulfill these high-performance requirements, a current-model logic (CML) based RO-VCO is presented as a possible solution capable of reducing the limitations of the commonly used structures and exploiting their advantages. The proposed hybrid VCO model includes passive components in its design which are the key parameters that define oscillation frequency of this structure. This tunable oscillator has been designed and tested in 65nm Bulk and 28 nm Fully depleted silicon-on-insulator (FDSOI) CMOS technologies The 65nm testchip was designed to compare the behavior of the proposed CML VCO with a current-starved RO and a radiation hardened by design (RHBD) LC-tank VCO in terms of tuning range, phase noise, Single event effect (SEE) sensitivity and design area. Simulations were carried out by applying a double exponential current pulse into different sensitive nodes of the three VCOs. In addition, SEE tests were conducted using pulsed laser experiments. Simulation and test results show that a CML VCO can effectively overcome the limitations presented by a RO-VCO and LC-tank VCO, achieving a wide range of tuning, and low sensitivity to noise and SEEs without the need for a large cross-section. Further studies of the proposed CML VCO were done on 28nm FDSOI in order to reduce the leakage current and increase the switching speed. the same current-starved VCO and CML VCO were implemented on this testchip, and simulations were performed by injecting a double exponential current pulse energy into the previously defined sensitive nodes. The results show SEE sensitivity improvement without narrowing the tuning range or affecting the phase noise response

    Matter-wave Atomic Gradiometer Interferometric Sensor (MAGIS-100)

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    MAGIS-100 is a next-generation quantum sensor under construction at Fermilab that aims to explore fundamental physics with atom interferometry over a 100-meter baseline. This novel detector will search for ultralight dark matter, test quantum mechanics in new regimes, and serve as a technology pathfinder for future gravitational wave detectors in a previously unexplored frequency band. It combines techniques demonstrated in state-of-the-art 10-meter-scale atom interferometers with the latest technological advances of the world's best atomic clocks. MAGIS-100 will provide a development platform for a future kilometer-scale detector that would be sufficiently sensitive to detect gravitational waves from known sources. Here we present the science case for the MAGIS concept, review the operating principles of the detector, describe the instrument design, and study the detector systematics.Comment: 65 pages, 18 figure
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