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Near Module Quality Ratings


Distribution of Modules by Rating |  Module Maps
Module Rating Definitions | How to Rate Modules

Summary Information

The Ratings Workbook at this link holds rating information on every near module. It is an Excel file, holding 16 Sheets, one Sheet for each Module Type. There is 1 column for the Review Board ratings assigned to each module. There is 1 column for each module's LOCATION, which is the Plane Number it is placed upon, with a shaded location box meaning that the module has not yet been used.

An additional PDF file, Modules On Planes lays out the 4 storage racks of assembled planes at New Muon, and is complementary to the Ratings Workbook. Each instrumented plane in the Near Detector is shown, one per line, in the order as it is located on one of the four storage stands at New Muon. There is a color-coding indicating the logical regions of the detector, and also indicating the "module quality usage" areas. The modules placed on each plane are listed, with a color coding as to module rating.

Distribution of Modules by Rating

There are two types of "perfect" modules, those with the Target and the Calorimeter A ratings. The "golden" section of the detector can contain ONLY Target rated modules; however, very specific types of minor problems on particular strips outside of the central beam region may be allowed in modules rated as Target, as described in the rating description below. Outside of the "golden" region, we adhere to the 1% rule << no more than 1% of the strips are imperfect >>. The only exception to this is in the Veto Section, where up to 3% imperfect strips is allowed.

What the 1% rule means in practice is :

  • no more than ONE imperfect module per plane; the majority of imperfect modules are allowed ONE bad strip (see rating definitions, below)
  • no more than 7 imperfect modules distributed among every 10 planes in the Forward section of the detector, outside of the "golden" region
  • no more than 10 imperfect modules distributed among every 10 planes in the Spectrometer section of the detector

See the Numbers Section, below, for details of what the 1% rule implies for the total numbers of imperfect modules which can be utilized in the Detector.

Module Rating Definitions

Some of the rating definitions specify boundaries by module type and strip number. For a map of module types and the strip numbering as reported by the Mapper results, this link to Near Plane Module Layouts will pop up a diagram in a separate window.

There are three basic levels for judging strips - the 60-20 level, the 50-30 level, and the Imperfect level

60-20 means : the strip has a light output at or above 60% of the nominal average at it's midpoint (nominally, the L200 mark), and no deviations ("dips") along the strip's length greater than 20%, up or down, from the fit to the strip's data

50-30 means : the strip has a light output at or above 50% of the nominal average at it's midpoint (nominally, the L200 mark), and no deviations ("dips") along the strip's length greater than 30%, up or down, from the fit to the strip's data

Imperfect means the strip fails the above two levels, for whatever reason. There can be many sub-classes of imperfections (low light, big dip, completely dead, etc).


Target Rating - most perfect - module can be used anywhere in the detector, but planes in the golden section MUST use modules which have this rating. We hope that MOST modules end up with this rating.

  • All strips in H (partial) modules and K (full) modules must meet the 60-20 level
  • Strips 1:10 in G and I (partial) modules, and strips 1:10 in J and L (full) modules, must meet the 60-20 level criteria.
  • The remaining strips in G, I, J and L modules must at least meet the 50-30 level
  • Strips 25:28 in G modules are not read out, and are not considered as part of this rating.
  • Strips in M and N modules can meet either the 60-20 or the 50-30 criteria
  • No imperfect strips are allowed, except where Review Board members agree to allow specific strips outside of the central beam region to have minor imperfections, for example a 40% dip near an end of a strip - all such discussions recorded for posperity

Type A Rating - nearly perfect - module can be used in any planes outside of the golden section of the detector.

  • All strips must meet either the 60-20 or the 50-30 criteria. For reasons mostly due to WHICH strips are at the 50-30 level, the module fails to have a Target Rating.
  • No strip in the module is at the imperfect level, except where Review Board members agree to allow specific strips outside of the central beam region to have minor imperfections - all such discussions recorded for posperity
  • Strips 25:28 in G modules are not read out, and are not considered as part of this rating.

Type B Rating - 1 imperfect strip - module can be used only in planes outside of the golden section of the detector, AND since one strip is imperfect, placement of the module must adhere to the 1% rule.

  • All strips, aside from the following exception, must meet either the 60-20 or the 50-30 criteria
  • No more than ONE strip in the module is at the imperfect level.
  • Strips 25:28 in G modules are not read out, and are not considered as part of this rating.

Spectrometer Rating - 2 imperfect strips - module can be used only in Veto planes, the red section in the above schematic, or in the grey portion of the Muon Spectrometer in the above schematic. To adhere to the 1% rule, and assuming most imperfect modules contain just 1 imperfect strip, very few modules with this rating can be used in the detector.

  • All strips, aside from the following exception, must meet either the 60-20 or the 50-30 criteria
  • No more than TWO strips in the module is at the imperfect level.
  • In general, all modules with this rating are Full plane module types. A few Partial module types with this rating can be used in the Veto section.

Module Maps and What to Look For

The Module Maps page is an indexed list of all the re-corrected module maps posted online. All the map files are PDF format; the first page holds summary plots, subsequent pages hold the data and fit for each strip in the module. Paper copies of all the first summary pages have been shipped to Reviewers.

One looks, for rating purposes, on the first page, at the center row right-hand plot "L200 fiber vs Strip", and also at the lower row left "20% deviants" and lower row center "30% deviants".

The dashed line passing through the points on the L200 plot is their average; the middle dashed line indicates the 60% light level, and the lower dashed line the 50% light level. If all points are above one or both these lines, and there are no deviants (deviant plots empty) then the conclusion is a fairly straight-forward Target or Type A rating. Most modules will require no further inspection than the plots on this first page.

Modules with "deviant" strips may require additional scrutiny. Each entry in a non-empty deviant plot indicates a strip with a dip in it's light level along it's length. The strip number is the horizontal axis. Even if the deviant strip(s) pass the 50% level, they should have their individual data and fit examined, using the plots posted online from the Module Maps page. The utilization of the module can depend on the location and severity of the dip. For example, a 20% dip in a strip far from the beam center, whose light level is otherwise far above the 60% level, can be rated Type A and therefore be used anywhere outside of the golden region of the detector. A module with a 30% dip in a strip which is otherwise just at the 50% level gets a Type B rating, but if the dip occurs at the end of the strip, and the strip is far from the beam center, then the Review Board can agree to use the module and NOT have it count against the 1% rule. It is modules such as these which must have some recorded comment from the Review Board, so their placement in the detector is documented for future reference.

Numbers - what can be utilized

Here is a summary of the total numbers of strips, and what the 1% rule implies.

  • There are 11,616 total strips in the entire Near detector
  • 4928 strips are in the Golden region - 0% rule applies
  • 6688 strips are in the remainder of the detector - 1% rule applies
  • The 1% rule means there can be no more than 67 imperfect strips in the entire detector.
  • Since most modules which contain imperfect strips will be allowed to contain only ONE, the 1% rule means that no more than 60 or so modules can be rated as Type B, and 3 or 4 can be rated Spectrometer.
  • The Golden region of the detector consists of 70 planes, containing 14 Full planes and 56 Partial planes. All of the modules on these must have a Target Rating.
  • Outside of the golden section, there are 93 planes, containing 43 Full and 40 Partial planes. There are a total of 6688 strips. The 1% rule allows 67 imperfect strips. In general there is just one imperfect strip per module...say 64 imperfect strips in 64 Type B rated modules. There are 16 module types (both views). Distributing the Type B rated modules evenly among all types, that is a limit of 4 Type B rated modules of each type. All other modules must be rated at one of the two higher levels, with a few Spectrometer rated modules allowed.


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Page last updated Monday, February 16, 2004

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