Detectors & MechanicalW.J. Llope

US DOE review of STAR TOFBNL, August 10-11, 2009

Outline:• TPC Support Fixture• Start Detector & TPMDst

Tray Mechanical - JerryGas System - LijuanVoltage Systems - Bertrand

1

TPC Support Fixture

Eight Trays “behind” the Four TPC Support Arms.Need fixture to support TPC while one arm is removed (East, 3 o’clock)

then install, cable, & test two west and two east traysThen repeat for East 9 o’clockUse eight commissioned trays from Run-9 in these locations.

1

6

11

16

21

2631

36

41

46

51

56

no LV

no HV

HV issue? no data

61

66

71

76

81

8691

96

101

106

111

116

TCPU

HV spikes

HV spikes

WEST

EAST

Batch 1Batch 2Batch 3 + Run-8 TraysBatch 4

Masked out of Level-0 Trigger:5, 49, 65, 99 TOF location

2

...designed by J. Scheblein (BNL)

Expected load = 6 tons

Test Load = 7.5 tons (125%)

Design Safety Factor = 6

3FEA Simulation

Trays to go behind the support arms are identified...

Expected to be installed by first week of October...

4

The fixture has been fabricated and is undergoing load testing.

Start Detector Status2x19 detectors, each Pb/Sci/R5946

|Z|~5.7 m, 4.24 < |η| < 5.1

Cosmic tests before Run-6single detector σ0 ~ 125 ps

Run-6:only 2 weeks of dataMOSFET-base failures at ~one/day.

Run-7 (Au+Au)new linear basesprimary input to STAR min.bias trigger

trigger Zvtx resn ~ 5 cmonly TOF-digitized data from last 2 days

canbus data (no event structure)un-triggered eventswest side onlysingle detector σ0 ~ 170 ps

recognized some ringing before Run-8

additional 12ns & 24ns cable sections usedto avoid HPTDC cross-talk

Run-8 (d+Au, p+p, & 9 GeV Au+Au)again, an input to STAR triggersingle detector σ0 ~ 130-140 ps

in both p+p and d+Au

Slew

corre

ctio

n tim

e diff

eren

ceTime Over Threshold (ns)

5

Basic problem was “parasitic inductance”some leads/traces too long

Investigated several “blue-wire” fixes...

un-modified

resistor modification

res. & cap. modification

−10 −5 0 5 10 15 20 25

−1

−0.8

−0.6

−0.4

−0.2

0PH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mVPH<50mV

−10 −5 0 5 10 15 20 25

−1

−0.8

−0.6

−0.4

−0.2

050mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV50mV<PH<100mV

−10 −5 0 5 10 15 20 25

−1

−0.8

−0.6

−0.4

−0.2

0100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV100mV<PH<500mV

−10 −5 0 5 10 15 20 25

−1

−0.8

−0.6

−0.4

−0.2

0500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V500mV<PH<1V

−10 −5 0 5 10 15 20 25

−1

−0.8

−0.6

−0.4

−0.2

01V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V1V<PH<2V

−10 −5 0 5 10 15 20 25

−1

−0.8

−0.6

−0.4

−0.2

02V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH2V<PH

decided instead to simply build new bases (few k$)

Used throughout Run-9, PMT ToT distributions much smoother than in Run-8

20 30 40 50 60 70

-700

-600

-500

-400

-300

-200

-100

0

6

V(+)

V(-)

TPMD

_st 4-2009Rice U

. Bonner Lab

1975 (2)

3400 (2)

4825 (2)

6250 (2)

7675 (2)

9100 (2)

10525 (2)

11,900

10800 TDIG

"0"

250

850

1450

2050

2650

3250

3850

4450

5050

5650

6250

6850

7450

8050

8650

9250

11,900

800 (4)

7400 (4)

7950 (4)

8200

9850

8050

8650

9250

300

L_1L_6

Bottom

Bottom

Bottom

Bottom

Bottom

Bottom

Bottom

Bottom

Bottom

Bottom

200

C1

C10

C11

C12

C13 C14

C15

C16

C18-1C18-10

C18-2C18-3

C18-4C18-5

C18-6C18-12

C18-11C18-9

C19-1C19-10

C19-2C19-3

C19-4C19-5

C19-6C19-12

C19-11C19-9

C17

C20-1

C20-10

C20-2

C20-3

C20-4

C20-5

C20-6

C20-12

C20-11

C20-9

C21-1C21-10

C21-2C21-3

C21-4C21-5

C21-6C21-12

C21-11C21-9

C22-1C22-10

C22-2C22-3

C22-4C22-5

C22-6C22-12

C22-11C22-9

C23-1

C23-10

C23-2

C23-3

C23-4

C23-5

C23-6

C23-12

C23-11

C23-9

C24-1C24-10

C24-2C24-3

C24-4C24-5

C24-6C24-12

C24-11C24-9

C25-1C25-10

C25-2C25-3

C25-4C25-5

C25-6C25-12

C25-11C25-9

C26-1C26-10

C26-2C26-3

C26-4C26-5

C26-6C26-12

C26-11C26-9

C27-1

C27-10

C27-2

C27-3

C27-4

C27-5

C27-6

C27-12

C27-11

C27-9

C28-1

C28-10

C28-2

C28-3

C28-4

C28-5

C28-6

C28-12

C28-11

C28-9

C29-1C29-10

C29-2C29-3

C29-4C29-5

C29-6C29-12

C29-11C29-9

C3 C4C5

C6 C7

C8

C9

D1

D2

D3

D4

D5-1

D5-10

D5-2

D5-3

D5-4

D5-5

D5-6

D5-12

D5-11

D5-9

F1

F2

H10

H12

H13

H2

H3

H5

2

139

40

J1

J12J24

J10J28

J11J13

J25J29

J14J26

2

139

40

J3

J15J27

J17J16

J32J33

J18J30

J19J31

2

139

40

J2

J5

J6

J8

J9

R25

R10

R11

R12R13

R14

R15

R16R17

R18 R19

R2

R20

R21

R22

R23 R24

R25-1

R25-10

R25-2

R25-3

R25-4

R25-5

R25-6

R25-12

R25-11

R25-9

R26-1R26-10

R26-2R26-3

R26-4R26-5

R26-6R26-12

R26-11R26-9

R27-1

R27-10

R27-2

R27-3

R27-4

R27-5

R27-6

R27-12

R27-11

R27-9

R28-1

R28-10

R28-2

R28-3

R28-4

R28-5

R28-6

R28-12

R28-9

R29-1

R29-10

R29-2

R29-3

R29-4

R29-5

R29-6

R29-12

R29-9

R3

R30-1

R30-10

R30-2

R30-3

R30-4

R30-5

R30-6

R30-12

R30-11

R30-9

R31-1R31-10

R31-2R31-3

R31-4R31-5

R31-6R31-12

R31-11R31-9

R32-1R32-10

R32-2R32-3

R32-4R32-5

R32-6R32-12

R32-11R32-9

R33-1

R33-10

R33-2

R33-3

R33-4

R33-5

R33-6

R33-12

R33-11

R33-9

R34-1

R34-10

R34-2

R34-3

R34-4

R34-5

R34-6

R34-12

R34-11

R34-9

R35-1

R35-10

R35-2

R35-3

R35-4

R35-5

R35-6

R35-12

R35-11

R35-9

R36-1

R36-10

R36-2

R36-3

R36-4

R36-5

R36-6

R36-12

R36-11

R36-9

R37-1R37-10

R37-2R37-3

R37-4R37-5

R37-6R37-12

R37-11R37-9

R38-1R38-10

R38-2R38-3

R38-4R38-5

R38-6R38-12

R38-11R38-9

R39-1R39-10

R39-2R39-3

R39-4R39-5

R39-6R39-12

R39-11R39-9

R4

R40-1R40-10

R40-2R40-3

R40-4R40-5

R40-6

R40-12R40-11

R40-9

R41-1R41-10

R41-2R41-3

R41-4R41-5

R41-6R41-12

R41-11R41-9

R42-1

R42-10

R42-2

R42-3

R42-4

R42-5

R42-6

R42-12

R42-11

R42-9

R5

R6

R7R8

R9

TP1

U1U2

U3

U4

U5

U6-1

U6-10

U6-2

U6-3

U6-4

U6-5

U6-6

U6-12

U6-11

U6-9

U7-1

U7-10

U7-2

U7-3

U7-4

U7-5

U7-6

U7-12

U7-11

U7-9

U8-1

U8-10

U8-2

U8-3

U8-4

U8-5

U8-6

U8-12

U8-11

U8-9

C30-1C30-10

C30-2C30-3

C30-4C30-5

C30-6C30-12

C30-11C30-9

R28-11R29-11

New TPMD (”TPMDst”)• Connector mapping now matches final TDIG to readout (6ch → 10ch)

5 boards → 3 boards, now all boards are easily accessible in the start-boxes.• pulse stretching circuit (as on stop-side) to measure LE and TE stamps in the same channels.• additional technical improvements

18 TPMDst boards assembled & tested, all functional... Ready for Run-10

TPMD TDIG TCPUTHUB

LVDS digitalPMT

signals

PMTsignals

PlatformQT

DAQ

TRG

TPMDst TDIG TCPUTHUB

LVDS digitalPMT

signals

PMTsignals

DAQ

PMTsignals

PlatformQT TRG

TPMDst Fast-ZLVDS digital TRG

Present

Run-10 (+ possible “Fast-Z” upgrade path)

7

upVPD Channel0 5 10 15 20 25 30 35

(ns)

0σ

0.1

0.15

0.2

0.25

0.3

0.35

0.4ToT & tLEADC & TACADC & tLEToT & TAC

200 GeV0 2 4 6 8 10 12 14 16

-1>)

(ns)

side

(1-<

Nσ

0.05

0.1

0.15

0.2

0.25

0.3

0.35

Clean

0 2 4 6 8 10 12 14 16

-1>)

(ns)

side

(1-<

Nσ

0.05

0.1

0.15

0.2

0.25

0.3

0.35

Dirty

-1sideN

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upVPD Performance in Run-9 “Backgrounds” (i.e. good hit confusion) increasing every run.....requires careful outlier rejection & multiple collision ID

Single Detector resolution ~140 ps, consistent with Run-8 result.

independent analyses using a differentoutlier rejection scheme by

Zebo Tang & Xiaoping Zhangas well

8

Start Detector in Low Energy Run-8 (9 GeV)some � problems triggering on actual collisions

Day = 94

upVPD coincidence efficiency ~ 60%

...heavily biased to peripheral collisions though

nprimary>0 (or nvertex>0)

Zvtx from upVPD timingvs Zvtx from tracking...

Zvtx resn ~ 22-24 cmno upVPD slewing correctionearliest hits on east and west

→ single det σ ~ 1ns (as expected!)

9

upVPD

BBC

TOF

Efficiency vs Beam Energy Simulation• UrQMD 2.3 events• exact detector positioning• simplified STAR geometry

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0.2

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10 10 2

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vent

8<b<12 fm4<b<8 fm0<b<4 fm

Resulting Efficiency/event vs √s and b

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5.07.69.212.317.3304562200

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UrQMD spectator ηybeamUrQMD spectator η - 1.6

→ need simple reshaping of BTofCalibrationMakerin progress now.... (needed early 2010) 10

Deliverables & Requirements

Start Detector38 channel “upVPD” built and in use since Run-7

System Total Time Resolutionrequirement is σtotal = σstart ⊕ σstop < 100±15 ps in full-energy Au+Au

use single detector resolution σ0 = 140 ps value seen in p+p Run-8 & 9(very conservative for Au+Au based on pVPD experience in Runs 2-5)

average number of dets/side w/ prompt hitsNside = 19 for centrality ~60% → 0%Nside = 5 for centrality ~80% → 60%

σside = σ0/√Νside → σstart = σ0/√(2Νside)→ σstart = 23 ps (60%-0%)→ σstart = 44 ps (80%-60%)

take σstop = 85 ps from Runs 8 & 9... (see subsequent talks)→ σtotal = 88 ps (60%-0%)→ σtotal = 96 ps (80%-60%) 11

Nvp

d (T

RG)

CTB sum

Run-7

Summary

• TPC Support Fixture fabricated and under test(Scheblein, Soja, Christie, Pendzick, et al.)

• upVPD2x19 channel “start” detector in use since Run-7

also a major component to STAR Level-0 minbias triggersNew PMT bases for Run-9

performed well, no failures18 improved TPMD boards (”TPMDst”) tested & ready for use

numerous improvements w.r.t. TPMDinstallation underway now

Single-detector time resolution in p+p ~ 140ps, consistent with Run-8implies system total time resolution σtotal ≤ 96 ps in full energy Au+Aubackgrounds/out-of-time hits becoming a significant issue

Efficiency vs √s and b in the Beam Energy Scan simulatedat lowest √s: efficiency drops with b......work started on a reshaped offline software to address this

12