1 / 8

Lateral x-ray : 4 marks vs 2 marks

Lateral x-ray : 4 marks vs 2 marks. Test perfomed using the plate 57 of one brick with 4 x-ray frontal marks and 4 x-ray lateral marks The distances between maps in micron are shown in the following slides (as depend on plate position) .

lynch
Download Presentation

Lateral x-ray : 4 marks vs 2 marks

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Lateralx-ray: 4 marks vs 2 marks • Test perfomed using the plate 57 of one brickwith 4 x-ray frontal marks and 4 x-ray lateral marks • The distances between maps in micron are shown in the following slides (as depend on plate position). Legend:- MAP:FXR4 : map evaluated using 4 x-rays frontal marks- MAP:LXR4 : map evaluated using 4 x-rays lateral marks- MAP:LXR2 min/max X side: map evaluated using 2 out of 4 x-rays lateral marks located on the plate side where x is minimum/maximum. (**) (*) A map is a transformation between stage coordinates and nominal (or detector or what.ever.you.want) coordinates (**) The same mark positions of the case with 4 marks are used to not introduce effects due to the mark position accuracy. The map is obtained by simply setting the other marks as NOT FOUND.

  2. MAP:FXR4 – MAP:LXR4 Distance between maps (micron) The rough positions of the marks used are shown in black (1° map) and in white (2° map)

  3. MAP:FXR4 – MAP:LXR2 minX side Distance between maps (micron) The rough positions of the marks used are shown in black (1° map) and in white (2° map)

  4. MAP:FXR4 – MAP:LXR2 maxX side Distance between maps (micron) The rough positions of the marks used are shown in black (1° map) and in white (2° map)

  5. Comments • The distance between MAP:FXR4 – MAP:LXR4 is below 10 micron over the whole emulsion plate • The map evaluated with only 2 lateral marks get worse and the distance can increase up to 50 micron on the opposite side of lateral marks . Let compare the 4-marks frontal x-ray map with a 2-marks frontal x-ray map obtained by simply setting as NOT FOUND the 2 marks with higher x positions … And what happen if we evaluate the distance between this map and the 2 marks lateral x-rays map?

  6. MAP:FXR4 – MAP:FXR2 minX side Distance between maps (micron) The rough positions of the marks used are shown in black (1° map) and in white (2° map)

  7. MAP:FXR2 minX side – MAP:LXR2 minX side Distance between maps (micron) The rough positions of the marks used are shown in black (1° map) and in white (2° map)

  8. Finalcomments • Changingfrom a 4 marksmapto a 2 marksmapintroduceserrors in the position estimation. Thisisalsotrueifyouhave 4 marksmapbutyoudidn’t find 2 marks. • Thisisnotexpectedifyou don’t change the map. Forexamplesifyouuseonly a 2 marksmapfor the entirebrick (i.e. in the scan-back). • Thisis due the differentnumberof free parametersavailablefor the transformation (6 in the case of 3 and more marks, 4 in the case of 2 marks). The scalingof Y coordinatescannotbewellestimatedbymeasutingonly 2 marks (withquite the same Y). • 4-marks lateralmarks are necessaryifyou don’t wanttomanagetheselargeerrors (at the beginningofscanback and at the end of the scanforth or everytimeyouchange the map).

More Related