A one-dimensional multi-element photo detector includes a photodiode array with a first upper row of photodiode pixels and a second lower row of photodiode pixels. The photodiode array is part of the photo detector. A scintillator array includes a first upper row and a second lower row of scintillator pixels. The first upper and second lower rows of scintillator pixels are respectively optically coupled to the first upper and second lower rows of photodiode pixels. The photo detector also includes readout electronics, which are also part of the photo detector. Electrical traces interconnect the photodiode pixels and the readout electronics.