A locking mechanism for scissors-type shear allows closing and locking of the shear even when the locking element is placed in a locked position before the shears are closed. The pre-combustion chamber assembly includes a pre-combustion chamber, a pressure-limiting device, and a fluid conduit. The collapsible rib and the pliable fabric cover are separable. In this way, a relatively large change in MCS may be accommodated, if warranted by the change in signal quality. The loading device may permit each of the plurality of cassettes to be independently interchanged with a separate cassette removably constraining a separate plurality of probes during mass spectrometric analysis, or for additional cassettes to be loaded into the device during analysis. By reducing the likelihood of void regions between adjacent semiconductor chips, it is expected that a method according to the exemplary embodiments of the present invention exhibit improved mechanical stability and reliability.