Cherenkov lightdetection by PPDs
Tohru Takeshia (Shinshu University)	

PD15 @ Moscow

T.Takeshita

PD15

PFA calorimeter•

Precise Physics

results will be
produced by highperformancedetector
T.Takeshita

tracker ECAL HCAL

PD15

PFA+Chrenkov• 3D ﬁne segmented calorimeter• with segmented active absorber• for Cherenkov light detection
heavy absorber• transparent absorber with thin
PPD
transparent

PPD
T.Takeshita

PD15

PFA+Chrenkov• 3D ﬁne segmented calorimeter• with segmented active absorber• for Cherenkov light detection
heavy absorber• transparent absorber with thin
PPD
transparent

PPDT.Takeshita

PD15

Cherenkov detection•• Cherenkov lights produced
emitted with θcradiator with refraction index =nθc90-θcθcby a particle perpendicular
Cherenkov angle θcto the detector nevernextracted from the radiator refraction angle θd• as far as n>1.414• assuming n =1
• crucial to have no air-gap

simulation by G4out

between a PPD and theT.Takeshita

n=1.0
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θd

EM shower• how about EM shower case?
• almost no direct Cherenkov
light ejected from LG to air

1GeV e- on 4cm LG

Cherenkov detection• assuming n =1.58• after LG n=1.80• without air gap• it is not obvious for aPPDPPD• depending on n ofglue
T.Takeshita

simulation by G4
n=1.80n=1.58
3GeV muon perpendicular
PD15

Cherenkov light• signiﬁcantly small number ofphotons than scintillation•

number of Cherenkov photons lead glass&22~(1-1/n )/λ• high refraction index n isdesiredtransparent• short λ emission• absorption by radiator
T.Takeshita

PD15absorber candidate• Lead Glass used for ECAL
• n=1.8, high densityρ〜5.4• transparent >360nm• Cherenkov photons ~1/λ• reduce Cherenkov-photons

3cmx3cmx4cm

2T.Takeshita

PD15

Lead Glass•• a MPPC (50um pitch) 3x3
LG : DF6 3x3x4cm3mm2 detects

CRs

3cmx3cmx4cm

MIP?

• ~5 p.e./MIP• with air gap• continue study
pedestal
T.Takeshita

9ADC
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wave length shift• wave length shifting
window• absorb and re-emit• diﬀerent direction• high refractiveindex is desired

heavy absorber
Cherenkov light

PPDdetection exp.

Trigger counter• performance should be tested
by high energy muon

• with 6x6mm2 PPD of 50um
PbWO4
LG:Cerenkov~70p.e./72mm2~82p.e./
144mm2~5p.e./9mm2zz zdetection exp.

Trigger counter• performance should be tested
by high energy muon

• with 6x6mm2 PPD of 50um
LG:Cerenkov~82p.e./144mm2~5p.e./9mm2zz zwavelength shifting• Cherenkov light generated ~1/λ2• short wavelength will be absorbed and• reemitted with longer λ• then could traverse radiator andextracted easily into PPD heavy absorber• quantum dots ~nmtransparent

PPD with QD• QD material window• shift the wave length and

QD win.

direction• any λdepending on thePPD

size of QD• could be directory on the
PPD-silicon
http://www.nanosysinc.com/what-we-do/quantum-dots/

PPD with QD• QD material window• shift the wave length and

QD win.

direction• any λdepending on thePPD

size of QD• could be directory on thePPD-silicon
http://www.nanosysinc.com/what-we-do/quantum-dots/

PPD with QD• QD material window• shift the wave length andQD win.

direction• any λdepending on thePPD

size of QD• could be directory on thePPD-silicon
http://www.nanosysinc.com/what-we-do/quantum-dots/

summery and outlook• Cherenkov light detection by PPD• crucial to have a good light contact

Cherenkov light
well localized in small area

• EM shower detection inabsorber•

5GeVπ- into Pb10+sc.5 HCAL

~num. Cherenkov photon

Lead Glassutilizing Cherenkov light det. =Lead Glassoπ rich• correlation seen
low probabilityT.TakeshitadE in scintillator~MIPS
PD15