Download - RICH 2002, Pylos, Greece1 Steven Blusk for the BTeV Collaboration Design of the BTeV RICH and its Expected Performance.

RICH 2002, Pylos, Greece 1

Steven Bluskfor

the BTeV Collaboration

Design of the BTeV RICH and its

Expected Performance


The BTeV Collaboration

Belarussian State- D .Drobychev, A. Lobko, A. Lopatrik, R. Zouversky

UC Davis - J. Link, P. Yager

Univ. of Colorado at BoulderJ. Cumalat

Fermi National Lab J. Appel, E. Barsotti, CN Brown, J. Butler, H. Cheung, G. Chiodini, D. Christian, S. Cihangir, I. Gaines, P. Garbincius, L. Garren, E. Gottschalk, A. Hahn, G. Jackson, P. Kasper, P. Kasper, R. Kutschke, SW Kwan, P. Lebrun, P. McBride, L. Stutte, M. Votava, M. Wang,J. Yarba

Univ. of Florida at Gainesville P. Avery

University of Houston K. Lau, B. W. Mayes, J. Pyrlik, V. Rodriguez, S. Subramania

Illinois Institute of TechnologyRA Burnstein, DM Kaplan, LM Lederman, HA Rubin, C. White

Univ. of Illinois- M. Haney, D. Kim, M. Selen, J. Wiss

Indiana University RW Gardner, DR Rust

Univ. of Insubria in Como-P. Ratcliffe, M. Rovere

INFN - Frascati- M. Bertani,L. Benussi, S. Bianco, M. Caponero,F. Fabri, F. Felli, M. Giardoni, A. La Monaca, E. Pace, M. Pallota,A. Paolozzi, A. Scicutelli

INFN - Milano – G. Alimonti,M. Citterio, P. D’Angelo, S. Magni,D. Menasce, L. Moroni, D. Pedrini,M. Pirola, S. Sala, L. Uplegger

INFN - Pavia - G. Boca, G. Cossail, E. Degliantoni, PF Manfredi, M. Manghisoni, M. Marengo, L. Ratti, V. Re,V. Speziali, G. Traversi

INFN - Torino N. Cartiglia, R. Cester,F. Marchetto, R. Mussa, N. Pastrone

IHEP Protvino, Russia A. Derevschikov, Y. Goncharenko,V. Khodyrev, A. Meschanin,

L. Nogach, K. Shestermanov,L. Soloviev, A. Vasiliev University of Iowa C. Newsom, R. Braunger

University of Minnesota V. V. Frolov, Y. Kubota, R. Poling, A. Smith Nanjing Univ. (China) T. Y. Chen, D. Gao, S. Du, M. Qi, BP. Zhang, JW Zhao Ohio State University K. Honscheid, & H. Kagan Univ. of Pennsylvania W. Selove Univ. of Puerto Rico A. Lopez, & W. Xiong Univ. of Science & Tech. of China - G. Datao, L. Hao, Ge Jin, L. Tiankuan, T. Yang, XQ Yu

Shandong Univ. (China) CF Feng, Yu Fu, Mao He, JY Li, L. Xue, N. Zhang, & XY Zhang

Southern Methodist University - T. Coan

SUNY Albany - M. Alam

Syracuse University

M. Artuso, C. Boulahouache,

O. Dorjkhaidav

K. Khroustalev, R.Mountain, R. Nandakumar, T. Skwarnicki, S. Stone, JC Wang, H. Zhao Univ. of Tennessee K. Cho, T. Handler,

R. Mitchell Tufts Univ. – A. Napier

Vanderbilt University W. Johns, P. Sheldon,

K. Stenson, E. Vaandering, M. Webster Wayne State University G. Bonvicini, D. Cinabro University of Wisconsin M. Sheaff

Yale University J. Slaughter York University S. Menary


Physics of BTeV

BTeV will vastly improve the constraints on the CKM anglesby making precision measurements of both the sides andthe angles over-constrain ().

Measurements and searches for rare and SM forbiddendecays “Beyond the SM” Physics.

B factories will provide valuable input on sin(2) and Vub,but they cannot compete with a hadron collider on measuring, and searches for new physics (even by 2007).

- They don’t produce BS

- (bb) is ~10,000X larger at the Tevatron than at (4S)


B Production at the Tevatron

b production angle

b production angle

The higher momentum b are at larger

Pseudo-rapidity

b production peaks at large angles with large bb correlation

b cross section ~ 100 b at 2 TeV 2x1011 b’s per 107 sec at L=2x1032 cm-2 s-1.b cross section ~ 100 b at 2 TeV 2x1011 b’s per 107 sec at L=2x1032 cm-2 s-1.


B Physics Detector “Wish List”

Detector Property

Precision 3D Tracking

Excellent Particle ID(K, , p, e, )

Excellent calorimetry

Detached Vertex trigger at lowest level trigger

BTeV


The BTeV Detector


RICH Specifications

Momentum Range of Interest

* p > 2-3 GeV for CP tagging * p < 70 GeV clean separation of 2-body modes: B, K, KK.

Minimize material in front of ECAL

Longitudinal space available ~3 meters

Desirable to detect Cerenkov photons in the visible range (minimize chromatic error, less sensitive to contaminants, etc)

Well-suited for a Ring Imaging Cerenkov Detector

Tagging kaons in BTeV Acc.


Radiators

Large momentum coverage requires a low index of refraction

gas radiator

We chose C4F10 because:* heaviest gas which has high transparency in the visible * wide usage in other HEP expt’s (e.g. Delphi, HERA-B, HERMES, LHC-b).

For momenta below 9.5 GeV/c neither K nor P radiate in C4F10

Separate liquid radiator for K/P separation below 9.5 GeV/c

Large momentum coverage requires a low index of refraction

gas radiator

We chose C4F10 because:* heaviest gas which has high transparency in the visible * wide usage in other HEP expt’s (e.g. Delphi, HERA-B, HERMES, LHC-b).

For momenta below 9.5 GeV/c neither K nor P radiate in C4F10

Separate liquid radiator for K/P separation below 9.5 GeV/c


The BTeV RICH

Arrays of163-channel

HPDs(~1000 in total)

PMT Arrays(~5,000 in total)

Sphericalmirrors

C5F12

Liquid Radiator

C4F10 gasvolume

Photons from gasare reflected offmirrors and focused at the HPD plane.

Photons from liquidare directly detected inthe PMTs.


Photon Angles

Track fromInteraction

HPDArray

PMTArray

Liquid radiator photons are detectedin PMT array.

Liquid radiator photons are detectedin PMT array.

LiquidRadiator

Gas RadiatorVolume

Gas radiator photons are

detectedin HPD array.

Gas radiator photons are

detectedin HPD array.

Mirror


Gas Radiator

Gas: C4F10 (n=1.00138): * K/ separation for 3 < p <70 GeV * P/K separation for 9.5 < p < 70 GeVc() ~ 0.43 mrad @ 70 GeV

Must keep C)/trk < 0.13 mrad

N() detected ~ 65 (simulation)

Total uncertainty per photon must be kept below ~1 mrad.

Requires ~1.5 mm segmentation

Well-suited for HPDs

No P/K separationbelow ~ 9.5 GeV with

gas alone


Detecting Gas Photonswith HPDs

* See talk by Ray Mountain

Started with 61-channel HPD that LHC-band DEP developed. We worked with DEP to develop 163-ch version|which would meet BTeV’s requirements.

Cross-focused onto hexagonal pixels Signal: ~5000 e- in Silicon.

Readout system is being developed by Syracuse in collaboration with IDE AS Norway.

HPD

e

163 channels~1.5 mm

-20 kV


HPD Hexad

Mu-metalshield

Readout Boardsare mounted here HPD

VA_BTEVASICs

(AS&D)

Full HPDArray


HPD Readout

VA_BTeV ASIC being developed in collaboration with IDE AS Norway(independent from HPD development)

Initial tests indicate that ~500 e-

noise level be achieved.

Threshold for each channel is adjustable.

Readout is binary (ON or OFF)

Testing of first prototypes is underwayat Syracuse. HPD Readout

Board

VA_BTeVchip


More on HPD Readout

Discharge of FE chip requires 2 beam crossings, so a hit channel is dead for the next crossing.

Simulated effect @ L=2x1032 cm-2 s-1. Find <10% loss of photons even in the busiest regions.(Much smaller elsewhere)

HPD#Y

HPD#X

Number of hit channels in consecutive beam crossings

per 163 channels


Liquid Radiator

C5F12 (n=1.24): * Extends P/K separation to p<9.5 GeV * Extends K/ separation into the p<3 GeV range

c() ~ 5.3 mrad @ 9 GeV

Must keep C)/trk<1.7 mrad

N() detected ~ 15 (simulation)

Total uncertainty per photon must be kept below ~7 mrad

Separate PMT system (3” PMT is acceptable)


Detecting Liquid Photons -- PMTs

Expect to use 3” tubes. Shielding necessary ( |B| < 15 G in PMT region)

Expect (

c) ~ 6 mrad, N(~15/trk (trk

c) ~ 1.6 mrad

PMT Layout in BTeV

Mu-metalshields

3”


Magnetic Shielding of PMTs

Unshielded

Unshielded

B Trans.PMTs from 4 different manufacturers

4.0

12.0 45.0

45.0

Shielded

Shielded

B Long.

Bmax=15 G


Preliminary Conceptual Tank Design

PMT Arrays

HPD Arrays


Liquid Radiator Conceptual Design

1 cm of C5F12

3 mm Carbon Fiber front window & 3 mm quartz back window

Split into 5 volumes to reduce pressure.

Structure is reinforced by CF posts

Total Material Budget: X0 ~ 8.7%

Simulations indicate negligible impact on 0 reconstruction since electrons from conversions are only in a very weak magnetic field.


Progress with Mirrors Measurements being taken on the test bench of the TA2 group at CERN. Several mirrors under study

COMPAS: glass, glass+foam back., CMA: Carbon fiber

Initial tests show that they meet spot size spec.

Rcurv=660 cm

Work being done byINFN Torino group

~60 cm



from Simulations


from Simulations


Efficiency vs Fake Rate

Clean separationof B from BK and BKK

For example:(B ): 80%

K Rejection ~ 95% KK Rejection > 99% The latter is importantbecause BsKK lieson top of B signal

B Simulationw/ 2 minimum biasevents.

Gas Radiator & HPDs

K+-

K+K-


Low Momentum K/P separation using Liquid

Radiator & PMTs

K and P cannot be separatedbelow 9.5 GeV/c in gas system.

Our simulations showed that we could improve D2 by ~25% for BS and ~10%for B0 using liquid radiator.

Mom. < 9 GeV/c


Expectations for D2

BS

CP side

Recoilingb-hadron

K+

Away-side tags

K–, -, e-, p, jet charge

Same-side particle tag

K+

S

tag

B

N

N

corr incorrtag tag

corr incorrtag tag

N N

N N

D =

Error on CP Asymmetry

21/CPA DTag Type

D2

SAway Side Kaon

Tag 6.0% 5.8 %

Same Side Kaon (Pion) Tag 1.1% 4.5%

Away Side Muon Tag 0.8% 1.3%

Jet Charge 1.4% 0.4%

Total 9.2 % 12.1 %

BTeV Expected

10 % 13 %


Test Beam – May 2003

ConcreteSupport Blocks

HPDEnclosure

MirrorAssembly

FrontEntrance Window

~15 HPDs to coverfull Cerenkov ring

~100 GeV beam

Will measure:

* resolution on Cerenkov angle * photon yield

We’ll also scan themirror to checksensitivity

Construction underway.


Summary

The BTeV RICH uses : gas system: C4F10 gas and HPDs, and liquid system: C5F12 and PMTs

to achieve excellent K/P separation for all relevant momenta less than 70 GeV/c.

Recent addition of the liquid radiator system will improve D2 for CP tag by ~25% for BS and ~10% for B0.

Initial tests of HPDs/PMTs look encouraging (see talk by R. Mountain)

Test beam next year to validate detector design and simulations.


Why did we punt on

Aerogel?Both gas & aerogel photons were detected in the HPDs

After removing photons which were consistent with more than 1 track, aerogelprovided essentially no K/P separation

The aerogel rings have too few photonsto compete with the bright gas rings

Low mult. event

High mult. event


Alternate solution fordetecting gas photons

(MA-PMT16)

Larger active region than 1st gen. lens system not required

Viable backup to HPDs slightly worse position resolution.. Currently being tested at Syracuse.