Abstract: An apparatus includes an input probe configured to be placed on a first cluster of u-bumps disposed on a semiconductor die, output probes configured to be respectively placed on multiple clusters of u-bumps disposed on the semiconductor die, the multiple clusters being separately connected to the first cluster. The apparatus further includes a space transformer and printed circuit board (PCB) portion including a current source configured to supply a current to the input probe placed on the first cluster, resistors having a same resistance and being connected to ground, and tester channels at which voltages are respectively measured, the tester channels being respectively connected to ends of the output probes respectively placed on the multiple clusters and being respectively connected to the resistors. The apparatus further includes a processor configured to determine whether the input probe is properly aligned with the first cluster, based on the measured voltages.

Abstract: A valve lifter assembly for an engine may include a valve lifter body, a roller pin mounted in the valve lifter body and having a crowned barrel portion, and a substantially cylindrical roller mounted about the crowned barrel portion of the roller pin. The roller may have a crowned outer surface with a cylindrical center portion having a constant outer diameter equal to a roller maximum outer diameter, and oppositely disposed variable outer diameter outer portions extending outwardly from either side of the cylindrical center portion toward corresponding roller ends of the roller with a roller outer diameter decreasing as the variable outer diameter outer portions extend outwardly from the cylindrical center portion. The valve lifter assembly may further include a clip having engagement surfaces that are machined to have complimentary shapes to corresponding engagement surfaces of the valve lifter body.

Abstract: A valve lifter assembly for an engine may include a valve lifter body, a roller pin mounted in the valve lifter body and having a crowned barrel portion, and a substantially cylindrical roller mounted about the crowned barrel portion of the roller pin. The roller may have a crowned outer surface with a cylindrical center portion having a constant outer diameter equal to a roller maximum outer diameter, and oppositely disposed variable outer diameter outer portions extending outwardly from either side of the cylindrical center portion toward corresponding roller ends of the roller with a roller outer diameter decreasing as the variable outer diameter outer portions extend outwardly from the cylindrical center portion. The valve lifter assembly may further include a clip having engagement surfaces that are machined to have complimentary shapes to corresponding engagement surfaces of the valve lifter body.

Abstract: A method for gain calibration of a gamma ray detector includes measuring signals generated by one or more light sensors of a gamma ray detector, generating one or more derived curves using the measured signals as a function of bias voltage and identifying a transition point in the one or more derived curves. The method also includes determining a breakdown voltage of the one or more light sensors using the identified transition point and setting a bias of the one or more light sensors based on the determined breakdown voltage.

Abstract: Present embodiments relate to the calibration of detectors having one or more arrays of pixelated detectors. According to an embodiment, a method includes detecting optical outputs generated by a plurality of scintillation crystals of a detector with an array of pixelated detectors, generating, with the array of pixelated detectors, respective signals indicative of the optical outputs, generating, from the respective signals, a unique energy spectrum correlated to each of the plurality of scintillation crystals, grouping subsets of the plurality of scintillation crystals into macrocrystals, determining a representative energy spectrum peak for each macrocrystal based on the respective energy spectra of the scintillation crystals in the macrocrystal, comparing a value of the representative energy spectrum peak for each macrocrystal with a target peak value, and adjusting an operating parameter of at least one pixelated detector in the array of pixelated detectors as a result of the comparison.

Abstract: Methods and systems for gain calibration of a gamma ray detector are provided. One method includes measuring signals generated by one or more light sensors of a gamma ray detector, generating one or more derived curves using the measured signals as a function of bias voltage and identifying a transition point in the one or more derived curves. The method also includes determining a breakdown voltage of the one or more light sensors using the identified transition point and setting a bias of the one or more light sensors based on the determined breakdown voltage.

Abstract: Present embodiments relate to the calibration of detectors having one or more arrays of pixelated detectors. According to an embodiment, a method includes detecting optical outputs generated by a plurality of scintillation crystals of a detector with an array of pixelated detectors, generating, with the array of pixelated detectors, respective signals indicative of the optical outputs, generating, from the respective signals, a unique energy spectrum correlated to each of the plurality of scintillation crystals, grouping subsets of the plurality of scintillation crystals into macrocrystals, determining a representative energy spectrum peak for each macrocrystal based on the respective energy spectra of the scintillation crystals in the macrocrystal, comparing a value of the representative energy spectrum peak for each macrocrystal with a target peak value, and adjusting an operating parameter of at least one pixelated detector in the array of pixelated detectors as a result of the comparison.