Update on the RICH Beamtest

The RICH Group

M. Artuso, S. Blusk, C. Boulahouache, J. Butt, O. Dorjkhaidav, A. Kanan, N. Menaa, R. Mountain, H. Muramatsu, R. Nandakumar,

K. Randrianarivony, L. Redjimi, R. Sia, T.Skwarnicki,S. Stone, J.C. Wang, H. Zhang

Syracuse UniversityH. CeaseFermilab

Jianchun Wang03/11/05

BTeV Collaboration meeting

Phase II Beamtest(01/10/05-01/31/05)

Special thanks to

Erik Ramberg, Dario Menasce, Lorenzo Uplegger,Dave Slimmer, Margaret Greaney, Terry Tope, et

al.

The DAQ system is more sophisticated than that of phase I. It is able to readout all MAPMTs for each event.

New firmware has been developed that allows individual track trigger using coincident signal of finger counters.

The bias setting of front end electronics has been optimized.

We developed new baseboard that provides a better match to the dynamic range of the front end electronics without sacrificing collection efficiency.

In M-TEST Area

MAPMTs

Beam(120 GeV p)

Glassmirror

Gas tank:C4F8O

and Argon

NIM

Virte x IIFG 456

Pa c ka g e

53 MAPMT Tubes mounted on baseboards in RICH enclosure

12 pairs of MUX/FEH boards inside the enclosure

10 had been used in data taking.

12 F-T boards mounted outside on the enclosure

24 50’ long cables

12 F-T boards6 pairs of PMC/PTA cards

in PCI expansion boxLinux box running

Pomone based DAQ

First Ring Observedat 01/28/05 13:15

Cross-talk between adjacent cells ?

Cross-talk or two real photon?

This is a good ring with about 40 photon as expected.

Horizontally adjacent cells in one MAPMT tube also have adjacent wires in cable, adjacent traces in PCB and adjacent channels in FEH ASIC.

Determination of HV Settings

MAPMT tubes are divided into 3 groups according to their gain, and applied different HV.Definition: two or more adjacent channels with hit form a cluster hit.The cluster hit may not correspond to only one photon, but with this treatment one can measure plateau.We decided to use 800/750/700 V as nominal HV.

Cluster Size In HV ScanBeam Background LED Pulser

There are LEDs inside enclosure to generate light pulses. This is useful to study cross talk effect. We also took data with background (pure electronic noise and light leaks). With 800/750/700 V setting, most of cluster hits in beam data are due to photons hitting adjacent channels. Only ~5% of total hits are due to cross-talk.

Threshold Scan

We use threshold DAC = 121 (44 Ke) as nominal threshold. We also took good data at even lower threshold DAC=125 (27 Ke).

The detection efficiency is a smooth function of threshold as expected which is good.

The last point is due to very low threshold that saturates the electronics.

Thr. ~ 27 KeThr. ~ 44 Ke

Mirror tilt angle

Bea

m in

clin

atio

n an

gle

Refrac

tive i

ndex

Fit these 3 parametersby minimizing:

2 2

( )

( )data MCi i

i pixels

I I

Parameter Determination

Mirror tilt angle is very close to the set value.Track inclination angle is close to zero indicating the quality of our initial mechanical alignment.Errors not are estimated yet.

Detector Alignment

265.32 mrad1.15 mrad

Detector Alignment StabilityMirror adjusted deliberately

Over ~ 100 hrs

1 mrad ~ ring shifts by 1 pixel/cell

Refractive Index

n=1.001306

4 8

0 0

1 ( 1) (1 1/

)/

) (C F O airmeasured r aiai rn

P Tf

Pn f

Tn

(6 2)%(98 1)%

4 81.001396 0.000030C F On

(preliminary)

( 1.001380)proposaln

4 8C F O( 1.001378)n Measurement at 412 nm using Michelson interferometry

Refractive Index Before Correction

The “index” n is determined from the 2 fit.

As function of run ID, the “index” roughly follows the trend of gas pressure.

The pressure (P), temperature (T) and gas purity correction needs to be made.

Single Photon Cherenkov Angle Resolution

This is a single run with nominal setting.

Cross talk and track direction dispersion contributes to the resolution in real data.

~ 0.79 mrad ~ 0.75 mrad

Data MC

Track Cherenkov Angle Resolution

Data = 0.118 mrad

MC = 0.111 mrad

Data Data

Single track peak<N>Data = 43.1

<N>MC = 40.5

The difference is about 5%, which is the same as cross talk effect.

Double Track Peak IssueSingle track peak

<N> = 43.1 = 6.5

Double track peak<N> = 76.8 = 10.2

<N> = 86.2

<N> = 76.9

Number of hits in double track events is about 10% lower than expectation.

The deficit is due to well known photon overlap effect, which would seldom happen in a real experiment.

This is proved in a simulation where we add hits from two real data single track events together.

Summary

The DAQ system in phase II beam test works very well.

With optimized baseboard voltage divider, FE bias setting the cross talk is reduced, while high efficiency in FE readout is maintained.

Preliminary result shows that the photon yield and Cherenkov ring resolution is consistent with expectation.

C4F8O is proved to be a suitable Cherenkov radiator.

We have developed a new ASIC and presently characterizing a single chip hybrid. We are seeking financial support from FNAL to finish this R&D.