A method of making a tiled detector of high energy radiation or particles such as X-ray, Gamma ray and photons the detector comprising: an (NxM) array of detector tiles (304, 304'), a scintillator layer; a common substrate layer; wherein the array of detector tiles (304, 304') is arranged between the scintillator layer and the substrate layer; wherein each detector tile (304, 304') has a front side facing the scintillator layer and a backside facing the substrate layer; the method being characterized in that it comprises the following steps: aligning detector tiles (304, 304') one after another and with their active side down on to an alignment fixture to form an array of detector tiles; temporally attaching a mechanical fixture to the backside of the aligned detector tiles forming the array, wherein the mechanical fixture is adapted to move in a vertical direction for each detector tile individually; removing the array of detector tiles from the alignment fixture; applying on a scintillator panel an optically clear film adhesive; using the optically clear film adhesive to couple the detector tiles (304, 304') on the scintillator panel; applying an adhesive on one side of the common substrate layer; wherein the adhesive compensates altimetry differences between the backsides of adjacent detector tiles; attaching the aligned tiles (304, 304') to the common substrate layer with the adhesive. an (NxM) array of detector tiles (304, 304'), a scintillator layer; a common substrate layer; wherein the array of detector tiles (304, 304') is arranged between the scintillator layer and the substrate layer; wherein each detector tile (304, 304') has a front side facing the scintillator layer and a backside facing the substrate layer; the method being characterized in that it comprises the following steps: aligning detector tiles (304, 304') one after another and with their active side down on to an alignment fixture to form an array of detector tiles; temporally attaching a mechanical fixture to the backside of the aligned detector tiles forming the array, wherein the mechanical fixture is adapted to move in a vertical direction for each detector tile individually; removing the array of detector tiles from the alignment fixture; applying on a scintillator panel an optically clear film adhesive; using the optically clear film adhesive to couple the detector tiles (304, 304') on the scintillator panel; applying an adhesive on one side of the common substrate layer; wherein the adhesive compensates altimetry differences between the backsides of adjacent detector tiles; attaching the aligned tiles (304, 304') to the common substrate layer with the adhesive. aligning detector tiles (304, 304') one after another and with their active side down on to an alignment fixture to form an array of detector tiles; temporally attaching a mechanical fixture to the backside of the aligned detector tiles forming the array, wherein the mechanical fixture is adapted to move in a vertical direction for each detector tile individually; removing the array of detector tiles from the alignment fixture; applying on a scintillator panel an optically clear film adhesive; using the optically clear film adhesive to couple the detector tiles (304, 304') on the scintillator panel; applying an adhesive on one side of the common substrate layer; wherein the adhesive compensates altimetry differences between the backsides of adjacent detector tiles; attaching the aligned tiles (304, 304') to the common substrate layer with the adhesive.