The Poor Man’s RICH Concept: A One-Dimensional Dual Radiator RICH

The Poor Man’s RICH Concept: A One-Dimensional Dual

Radiator RICH

Joerg Reinhold

Florida International University, Miami

presented at

Hall C Summer Workshop

August 7, 2009

8/7/09 Joerg Reinhold, FIU 2

A “poorly” funded pet projectin collaboration with

• Michael Carl, FIU M.S. 2003 M. Carl, J. Reinhold, et. al., NIM A527 (2004) 301.

• Brian Beckford, FIU M.S. 2008

• Naipy Perez, FIU M.S. 2006

• Tohoku University


Cherenkov Radiation TriviaPrediction 1889? Noble Prize in Physics 1958

Pavel Alekseyevich Cherenkov Il´ja Mikhailovich FrankIgor Yevgenyevich Tamm

Cerenkov, C. R. Ac. Sci. U.S.S.R. 8, 451 (1934)Frank and Tamm, C. R. Ac. Sci. U.S.S.R. 14, 109 (1937)

€

cosΘ =1

βn⇒ β thr. =

1

n

d2N

dEdx=

2πα z2

hcsin2Θ or

d2N

dλ dx=

2πα z2

λ2sin2Θ

Np.e. = N0L sin2ΘCh with N0 =370 z2

cm eVεcollεdet dE∫

Typical bi - alkali cathode : εdet dE ≈ 0.27 eV∫Np.e. =100 cm-1 L εcoll sin2ΘCh

See e.g. O. Heaviside, Electromagnetic Theory(Chelsea Publishing Company,New York, 1971)

Oliver Heaviside


Motivation: Jefferson Lab at 12 GeV

PID with Cherenkov detectors

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Ring Imaging Cherenkov Detector (RICH)



Image from P.A. Cerenkov, Radiation of Particles Moving at a velocity exceeding that of light,and some of the possibilities for their use in Experimental Physics. Nobel Lecture(1958).







Example: 1m x 1m area 1cm2 pads => 10,000 channels1cm stripes w/2-sided readout => 200 channels


Nuclear Instruments and Methods in Physics Research A333 (1993) 458-463North-Holland

A RICH detector for velocity determination of heavy ionsK. Zeitelhack, J. Friese, HA. Körner, J. Reinhold and R. SchneiderPhysik-Department E12, TU Munchen, Germany


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Poor Man’s RICH Concept



QuickTime™ and aBMP decompressor


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nWLS =1.49⇒ Θcrit. = 42o for total int. refl.

⇒ 49% of shifted photons reach PMTs

with wave shifting Q.E. ≈ 84% ⇒ εcoll ≈ 41%


Wavelength Shifter PropertiesCharles Hurlbut, ELJEN Technology, Sweetwater TX,

www.eljentechnology.com, private communication



Waveshifting quantum efficiency ~ 84%.


KEK PS Experiment T554





•30 cm x 10 cm x 1 cm WLS•2 5-inch PMTs (Photonis)•8-mm fused silica radiator•Hadron beam line with p, K, up to 2 GeV/c•Scintillator TOF for PID


T554 Results










T554 Results



€

1- param. fit :

fixed nrad (λ = 350nm) =1.4767

⇒ εcoll. = 63.2%

2 - param. fit :

nrad =1.49 and εcoll. = 61.5%

w/out reflection losses at radiator/air & air/WLS boundaries


T554 Results: Discussion

•Digitized Q.E.s & transm.•Fold with Cherenkov spectrumExpect coll~65%

Agrees with external collectionHowever internal ~41%??Need to study theory ofCherenkov in absorbing media


Monte Carlo Simulation



•10 cm n=1.015 aerogel radiator•100 cm distance aerogel-WLS•50 WLS bars, 1 cm widecoll=61.5%






MC Disributions & Likelihood PID

€

L Nhits,b, Np.e.,b( ) = Np.e.,b

Nhits,b e− Np.e.,b

Nhits,b!

Only consider "hit" or "not hit":

L Nhits,b = 0, Np.e.,b( ) = e− Np.e.,b

L Nhits,b ≥1, Np.e.,b( ) =1− e− Np.e.,b

LPIDi = L Nhits,b, Np.e.,b( )bars

∏

lnLPID= i = lnL Nhits,b, Np.e.,b( )bars

∑

LPID= inorm =

lnLPID= i

lnLp + lnLK + lnLπ


PID Efficiencies: 10 cm n=1.015



protons

kaons

pions

€

p ≤11 GeV : ε pp ≈100%

p >11 GeV : ε pp ≈ 98%, εpK ≈ 2%

p ≤ 8 GeV : εKK > 95%, εpK ≈ 2%

p >10 GeV : εKK < 70%, εKp ≈ 30%,εKπ ≈10%

εππ ≈ poor


Distributions at p=12 GeV10 cm n=1.015 aerogel radiator


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p

K

p

K




Dual Radiator10 cm n=1.015 & 100 cm C4F10



proton

kaon

pion


Comparison with other RICH



[14] N. Akopov et al. The HERMES dual-radiator ring imaging Cherenkov detector. Nuc. Inst. Meth. Phys. Res. 479 (2002) 511-530.[37] P. Di Nezza, Hadron Suppression in DIS at HERMES. J.Phys.G: Nucl.Part.Phys.30(2004)S783-S790.[38] K.Suetsugu, Performance of Pion and proton identication with Ring Imaging Cerenkov Counter of HERMES. Master's thesis, Tokyo (February 2001). DESYTHESIS-2001-016.[40] A. Papanestis, The Ring Imaging Cherenkov Detectors for LHCb. International Europhysics Conference on High Energy Physics, PoS(HEP2005)375.[41] E. Nappi, Particle Identication Techniques. PhD Dissertation, 2005.


Summary & Outlook

• WLS collection efficiency ~ 62%• 1-dim RICH w/PID comparable to existing

RICH• WLS are low-cost options for large area

segmented photon collectors• Need more realistic MC: angular distributions,

Rayleigh scattering, …

• Measure coll for thin long WLS

The Poor Man’s RICH Concept: A One-Dimensional Dual Radiator RICH

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