Detector position on GEM inst at ISIS

there are quite a lot of non empty spectra in the GEM data that have no detID and detectorPosition associated to them:

spectra 14 to 100
spectra 145 to 160
spectra 310 to 325
spectra 5210 to 5929

the correct information in stored in the UDET variable in the isis_vms_compat group but I don’t think that detID is taking that information from there.
Is it possible to have this fixed?

Hi Davide,

Historically there had always been a bank on GEM that had been ignored in the Mantid IDF but I must admit I don’t really no why.

The reason Mantid shows no det ID/position in the table is due to the fact that those detectors are not defined in the GEM IDF. Looking at the relevant section of the IDF I can see


  <idlist idname="monitors">
    <id start="611" end="612" />
    <id val="621" />
    <id start="631" end="634" />
    <id start="641" end="644" />
  <idlist idname="bank1">
    <id start="101001" end="101045" />
    <id start="102001" end="102060" />
    <id start="103001" end="103060" />
    <id start="111001" end="111045" />
    <id start="112001" end="112060" />
    <id start="113001" end="113060" />
  <idlist idname="bank2">
    <id start="201001" end="201080" />
    <id start="202001" end="202080" />
    <id start="211001" end="211080" />
    <id start="212001" end="212080" />  

  <idlist idname="bank3">
    <id start="301001" end="301090" />
    <id start="302001" end="302090" />
    <id start="303001" end="303090" />
    <id start="304001" end="304090" />
    <id start="305001" end="305090" />
    <id start="311001" end="311090" />
    <id start="312001" end="312090" />
    <id start="313001" end="313090" />
    <id start="314001" end="314090" />
    <id start="315001" end="315090" />    

  <idlist idname="bank4">
    <id start="401001" end="401100" />
    <id start="402001" end="402100" />
    <id start="403001" end="403100" />
    <id start="404001" end="404100" />
    <id start="405001" end="405100" />
    <id start="406001" end="406100" />
    <id start="407001" end="407100" />    
    <id start="411001" end="411100" />
    <id start="412001" end="412100" />
    <id start="413001" end="413100" />
    <id start="414001" end="414100" />
    <id start="415001" end="415100" />
    <id start="416001" end="416100" />
    <id start="417001" end="417100" />    
  <idlist idname="bank5">
    <id start="501001" end="501120" />
    <id start="502001" end="502120" />
    <id start="503001" end="503120" />
    <id start="504001" end="504120" />
    <id start="505001" end="505120" />
    <id start="506001" end="506120" />
    <id start="507001" end="507120" />
    <id start="508001" end="508120" />
    <id start="509001" end="509120" />
    <id start="511001" end="511120" />
    <id start="512001" end="512120" />
    <id start="513001" end="513120" />
    <id start="514001" end="514120" />
    <id start="515001" end="515120" />
    <id start="516001" end="516120" />
    <id start="517001" end="517120" />
    <id start="518001" end="518120" />
    <id start="519001" end="519120" />
  <idlist idname="bank6">
    <id start="601001" end="601040" />
    <id start="602001" end="602040" />
    <id start="603001" end="603040" />
    <id start="604001" end="604040" />
    <id start="605001" end="605040" />
    <id start="606001" end="606040" />
    <id start="607001" end="607040" />
    <id start="611001" end="611040" />
    <id start="612001" end="612040" />
    <id start="613001" end="613040" />
    <id start="614001" end="614040" />
    <id start="615001" end="615040" />
    <id start="616001" end="616040" />
    <id start="617001" end="617040" />
    <id start="701001" end="701080" />
    <id start="702001" end="702080" />
    <id start="703001" end="703080" />
    <id start="704001" end="704080" />
    <id start="705001" end="705080" />
    <id start="711001" end="711080" />
    <id start="712001" end="712080" />
    <id start="713001" end="713080" />
    <id start="714001" end="714080" />
    <id start="715001" end="715080" />

then taking spectrum 14-100 as an example (and looking at a recent NeXus file):

  • the detector IDs in the UDET table are in the range 821001 - 83120 but
  • the IDF doesn’t have any knowledge that those detectors exist so Mantid can’t assign a valid detector to them.

In order for all spectra to show up then we’ll need to update the IDF with the valid detector IDs. Is that something you are able to do or would like us to assist with?