JAN. 2000 Commissioning Run Mark D. Baker

Commissioning ConfigurationMark D. Baker

(+ Park +Olszewski+Katzy +Wozniak + …)

• Purpose of Comm. Run

• Decisions for Comm. Run

• Quality of Full vs CR config.

• Open Issues

• More general year-1 issues

JAN. 2000 Commissioning Run Mark D. Baker

Overview

• 1/2 of 1 Vertex Detector (+Y, +Z)– Choose (+Y, +Z),– It will work. 1 (or 2) full detectors better.

• 1/8 Octagon: arbitrarily choose: MOF*– It will work. Full octagon+rings better.– Do we want a sensor lined up with the spect.?

• Spectrometer: Planes A-E (+partial G??)– A-D necessary, E (or F) exists

• Year 1: Block Spectrometer for a period?

JAN. 2000 Commissioning Run Mark D. Baker

Proposed Vertex Detector

VTA2 VTA3

VTB2 VTB3

VTB6 VTB7

JAN. 2000 Commissioning Run Mark D. Baker

1/2 Vertex works for Z=0->12cm

8101218 16 14

Half VTX Detector

1 Full VTX Detector

(cm)

JAN. 2000 Commissioning Run Mark D. Baker

Eta coverage of Spectrometer vs. Z

Zvtx

JAN. 2000 Commissioning Run Mark D. Baker

Eta coverage of Spect. & VTX.

Zvtx

+Z VTX-Z VTX

JAN. 2000 Commissioning Run Mark D. Baker

Proposed Octagon Configuration

VT**

P***

MOF*

JAN. 2000 Commissioning Run Mark D. Baker

Multiplicity Simulation

True Nch for |<5.3|

Rec. Nch Rec. Nch

Full Octagon + Rings +VTX Commissioning Config.

HIJING Inclusive sample, ZVTX=0

True Nch for |<3.2|

N>3000 (20%)=0.2%=2%

N>3000 (20%)=-0.7%=4.5%

JAN. 2000 Commissioning Run Mark D. Baker

Event-by-event

Full Octagon + Rings +VTX Commissioning Config.

HIJING+PL Central event, ZVTX=0

JAN. 2000 Commissioning Run Mark D. Baker

Proposed Spectrometer Config.

BDF exist

AC can be built from spares.

Build AC!

JAN. 2000 Commissioning Run Mark D. Baker

Spectrometer

• All attempts to find BDF-only tracks in high-multiplicity ER and MC events have failed!

• The various successful spectrometer MC results assume perfect ABCD or more.– Track finding– 3D Vertex Finding– F plane provides redundancy. It exists!

JAN. 2000 Commissioning Run Mark D. Baker

A Central event in PHOBOS

JAN. 2000 Commissioning Run Mark D. Baker

Perfect ABCD w/ VTX

Ghosts @ 2% level

True

Rec.

JAN. 2000 Commissioning Run Mark D. Baker

Perfect ABCD w/o VTX

True

Rec.

JAN. 2000 Commissioning Run Mark D. Baker

B-D-F

• BDF no VTX in MC (min. bias): – Efficiency drops to ~50%, Ghosts increase to ~30%

Real data - Eng. Run

JAN. 2000 Commissioning Run Mark D. Baker

Conclusion

• VTA2-3, VTB2-3, VTB6-7

• MOF*

• P-arm planes: A, B, C, D, F– Build 2 more spare type 1 planes

• Open questions, under active study:– Install MOA7 now? (Judith+Inkyu)– Install MOE6-8 for year 1? (Inkyu)