Calculate window values from radius, strip number and open aperture

[jovoy]

The following is a method that calculates the X-ray windows strip width and distance from each other, using the radius, number of strips and the open aperture. This is useful as companies give these values and one doesn't have to calculate it by hand. Should be implemented in TRestAxionXrayWindow .

proc calcWindowVals(radiusWindow: MilliMeter,
                    numberOfStrips: int,
                    openApertureRatio: float): tuple[width: MilliMeter,
                                                      dist: MilliMeter] =
  let
    totalArea = π * radiusWindow * radiusWindow
    areaOfStrips = totalArea * (1.0 - openApertureRatio)
    #width and distance between strips per strip;
    #the width on both sides is a whole width
    #(Don't know what to do about the additional string width)
    #not important at high strip number but at low like CAST
    dAndwPerStrip = radiusWindow * 2.0 / (numberOfStrips.float + 1.0)
  var
    lengthStrip: mm
    lengthAllStrips: mm

  for i in 0..(numberOfStrips/2).round.int - 1:
    lengthStrip = sqrt(radiusWindow * radiusWindow -
      (i.float * dAndwPerStrip + 0.5 * dAndwPerStrip) *
        (i.float * dAndwPerStrip + 0.5 * dAndwPerStrip)
    ) * 2.0
    lengthAllStrips = lengthAllStrips + lengthStrip
    echo lengthStrip

  lengthAllStrips = lengthAllStrips * 2.0

  let
    widthStrips = areaOfStrips / lengthAllStrips
    distStrips = dAndwPerStrip - widthStrips
  echo widthStrips
  echo distStrips
  result = (width: widthStrips, dist: distStrips)