CERN September 29, 20041W.H.Trzaska HIP Jyväskylä T0 – TDR 22 nd LHCC meeting; Open Session CERN, September 29, 2004 W.H.Trzaska (for T0 collaboration)

CERN September 29, 2004 1W.H.Trzaska HIP Jyväskylä

T0 – TDR

22nd LHCC meeting; Open Session

CERN, September 29, 2004

W.H.Trzaska

(for T0 collaboration)

Results and conclusions from the June 2004 comprehensive test run

Milestones

Cost estimate


Experimental set-up

6 m of cable

25 m of cable

PMTsPMTs

ShoeboxShoebox

Main

electronics

Main

electronics

TRD TRD


Typical TOF spectrum obtained with a pair of identical detectors

0

20

40

60

80

100

120

-200 -100 0 100 200

Time of filight [ps]

Co

un

ts

FWHM = 94 ps

35.2TOF

TOF

FWHM

2TOF

PMT

psPMT 28


Measured time resolution

Radiatordiameter

FWHMTOF

SigmaPMT

30 mm122 ps 140 ps

37 ps 42 ps

26 mm112 ps 128 ps

34 ps 39 ps

20 mm94 ps

115 ps

28 ps 35 ps

* With shoebox (worsens resolution by 20 ps)


Amplitudes

• For easier comparison the areas under the peaks were normalized to 10000

• The amplitudes were taken with the same PMT and at the same HV, just the radiators were changed

0

500

1000

1500

0 200 400 600

Amplitude [mV]

Co

un

ts (

no

rma

lize

d)

30 mm26 mm20 mm


Efficiency as function of threshold

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100

0 200 400 600

Threshold [mV]

Re

l. E

ffic

ien

cy

[%

]

30 mm26 mm20 mm

• At very low threshold values registration efficiency for particles entering perpendicular to the front surface of the radiator is simply proportional to the area of that surface: 100,75, 44%

• If the threshold value has to be raised (noise from other detectors, deterioration of detectors or electronics, etc.) the 20 mm radiator may turn out to be the best choice due to its excellent response function


T0 Efficiency in p – p collisions

Radiator diameter

T0 configuration

12 - 12 12 – 24

30 mm 53 %

20 mm 36 % 49 %


Backsplash spectrum (20 mm quartz)

• The efficiency for backward particles is the same as for forward particles but they can be efficiently separated by adjusting the threshold value

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1000

1500

2000

0 200 400 600

Amplitude [mV]

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ts

20 front20 back

Calculations by Alla Maevskaia 9W.H.Trzaska HIP Jyväskylä

Backsplash in 200 PYTHIA events

backsplash

Alla Maevskaia, INR RAS,Moscow FWD meeting 21.09.2004

T0-CT0-A


Conclusions I (physics)• For all reasons except the

efficiency in p-p collisions the 20 mm radiator is by far the best choice. – excellent pulse shape– 1/4 MIP resolution!

• The efficiency can be restored, for instance, by increasing the number of detectors in T0-A (next T0 upgrade)

• Decision expected on Nov 2004 TB


Conclusion II (electronics)

• We have prototype of the shoebox and of all key electronics (Vertex, MPD, MT, VDU, QTC) – shoebox should work for V0 as well– work on DCS in progress– readout test (full chain) in 2005

• Better pulse shape (20 mm radiator) reduces the dynamic range – use of off-the-shelf CFDs becomes possible– high threshold setting possible– stable performance


T0 mechanics milestones

• No concern:– T0-C prototype

ready– Integration

completed– Waiting for freezing of RB24

parameters to complete the design and order the production

• Production cycle 3-6 months

• Should be completed in 2005


T0 electronics milestones

• No major concern:– Prototypes of all dedicated T0

electronics build and tested– Excellent test results– Close collaboration with V0:

• PMT, front-end (next meeting 10/04)

• trigger-specific electronics (11/04)

• HV, LV, DCS?

– T0 will use TOF readout(slightly modified)

ShoeboxShoebox

Main

electronics

Main

electronics


Some solid dates for T0• Nov 2004: Freezing radiator size• Dec 2004: Electronics Design Review (joint with V0)

• Feb 2005: Detector module frozen; mechanics PRR

• Sep 2005: Full chain readout test• Dec 2005: T0 Mechanics ready

• Feb 2006: Electronics PRR• Jun 2006: T0-C ready for installation in ALICE; installation of electronics at CERN;

tests of the installed T0-C• Dec 2006: T0-A ready for installation in ALICE; tests of the installed T0-A


T0 cost estimate: 318 kCHF Item N. of units unit price total price Subtotal

€ %Detector 54,000 25PMT + base 40 1000 40,000Mechanics 10,000Prototype 4,000Electronics 88,000 42Modules and components 78,000VME 1 9000 9,000mechanics 1,000Laser Calibration System 27,500 13Laser 1 15000 15,000Fiber optics, splitters, etc. 10,000Attenuator 2,500Cables and connectors 12,440 6cables 2880 1.5 4,320HV connectors 140 30 4,200SMA connectors 392 10 3,920HV and LV power 30,050 14

317,985 CHF 211,990 100


Referee question: delay vs. HV

-2

-1.5

-1

-0.5

0

700 1000 1300 1600 1900 2200

dt,

ns

dt B=0

dt B=0,3

dt B=0

dt B=0.5

1.5 ps / V1.5 ps / V

Documents

CERN September 29, 20041W.H.Trzaska HIP Jyväskylä T0 – TDR 22 nd LHCC meeting; Open Session CERN, September 29, 2004 W.H.Trzaska (for T0 collaboration)