Quantum computer chip based on spin qubits in diamond uses modules that are entangled with on-chip optical links. This enables an increased connectivity and a negligible crosstalk and error-rate when the number of qubits increases onchip. Here, 3D integration is the key enabling technology for a large-scale integration of the diamond spin qubits with photonic and electronic circuits for routing, control and readout of qubits. There are several engineering challenges to integrate the large number of spins in diamond with the on-chip circuits operating at a cryogenic temperature. In this paper we will address challenges, present recent results and discuss future outlook of the integration technology for realization of a scalable quantum computer based on diamond spin qubits.

We witness many severe accidents in different sectors worldwide every year, resulting in fatalities, injuries, environmental pollution, property loss, etc. Safety management aims to use interventions to prevent these undesired events and thus avoid different kinds of loss. Various interventions that have different safety performances and costs are available for managers; one safety intervention may have multiple functions, such as avoiding fatalities and protecting the environment. As a result, we need to know the value of safety when deciding on investment in interventions. To support decision-making on safety management, the Safety & Security Science Group in Delft University of Technology (TUD) conducted a project on the value of safety to get insight into the values considered in the context of safety. Four research questions have been answered, as follows: what are the values of safety? what methods are used to measure the value of safety? what are the limitations of past research? what gaps have been identified? what is the roadmap for future safety management?