The BelleIIspectrometerattheSuperKEKBe+e collider will
be dedicatedtoprecisemeasurementsofrareprocessesindecays
of BandDmesons,andtauleptons.Itwillcollecta50timeslarger
data samplecomparedtotheBelleexperiment.Duetomuch
higher eventratesandbackground,asignificant upgradeofthe
detectorisneeded(Fig. 1) [1]. Intheforwardregionofthe
spectrometer,inthesmallspacebetweenthedriftchamberand
the electromagneticcalorimeter,aparticleidentification deviceis
envisaged,whichshouldenabletheidentification ofcharged
particles intherangefrom0.5to4GeV/c. Duetothelimited
space available,wehavedecidedfortheproximityfocusingRICH
with aerogelastheradiator.
The designcriteriashouldmeetthephysicsrequirementsofthe
identification system:thedeviceshouldhaveimproved π=K
separation capabilityintheforwardregionwithrespecttothe