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E. MétralE. Métral

ENGINEERING DESIGN REVIEW (EDR) FOR THE

TOTEM ROMAN POTS (Thursday 24 Nov. 2005)

Charge to the Review Committee (from E. Tsesmelis, TS/LEA)

Check that the TOTEM Roman Pots perform according to the intended specifications

Endorse the general scenario for the engineering design, assembly and mounting of the TOTEM Roman Pots

Approve the TOTEM Roman Pot concept to allow detailed engineering drawings and technical specifications to proceed

Check the project organization, safety issues and compatibility with neighboring (machine) systems

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AGENDAAGENDA 1. Introduction (10') EMMANUEL TSESMELIS (TS-LEA)

2. Roman Pot Design (35') ( Slides ) MARCO ORI UNNO (PH-TOT)

3. RF Issues (20') ( Slides ) MARI O DEI LE (PH-TOT)

4. Thin window design (20') ( Slides ) SERGE MATHOT (TS-MME)

09:55 Coffee break

5. Vacuum integration at 147 m and 220 m (20') ( Slides ) CHRISTI AN RATHJ EN (AT-VAC)

6. Vacumm issues (20') ADRIANA ROSSI (AT-VAC)

7. Radiation environment and energy deposition in the thin window (20') ( Slides )

EVANGELIA DI MOVASI LI (TS-LEA)

8. Planning and installation (20') MARCO ORI UNNO (PH-TOT)

9. ATLAS Roman Pots at IR1 (20') ( Slides ) BENI AMINO DI GI ROLAMO (PH-ATT)

12:05 Lunch break

10. Closed session (1h00') Review Committee

11. Comments from the Review Commitee (30') EMMANUEL TSESMELIS (TS-LEA)

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The TOTEM Experiment at LHCThe TOTEM Experiment at LHC

Forward Physics at Interaction Point 5

Elastic p-p scattering Total p-p cross section Diffractive physics Absolute luminosity measurement

Needs detection of leading protons with very small scattering

angles (few μrad)

Elias Métral, RLC meeting, 02/12/2005

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ROMAN POT DESIGN (1/13)ROMAN POT DESIGN (1/13)TOTEM+CMS Detector Configuration

RP1RP1 RP2RP2 RP3RP3

220 m220 m(180 m)(180 m)147 m147 m

~14 m

T1: 3.1 < < 4.7

T2: 5.3 < < 6.5

10.5 m T1T1 T2T2

HF

Symmetric experiment: RPs on both sides!

Elias Métral, RLC meeting, 02/12/2005

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ROMAN POT DESIGN (2/13)ROMAN POT DESIGN (2/13)

1. The Roman Pot, an historically proven technique for near beam physics: ISR, SPS, TEVATRON, RICH, DESY

2. A CERN in-house technology: ISR, SPS-UA4, CDF

Primary Vacuum

Detector

Thin window

Beam

Secondary Vacuum

Vacuum Chamber

Bellow

Beam

CERN for CDFCERN for SPS (UA4)

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ROMAN POT DESIGN (3/13)ROMAN POT DESIGN (3/13)

• Very close to the beam operation (10σ ~ 0.8mm)

• Secondary vacuum separation for detectors and cables (no outgassing)

• High mechanical reliability of the thin window on the pot

• Shielding of RF pick-up on the detector/electronics

• High resolution, precision and repeatability of the movements

Constraints/Requirements for TOTEM

Elias Métral, RLC meeting, 02/12/2005

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ROMAN POT DESIGN (4/13)ROMAN POT DESIGN (4/13)

Roman Pots are in many aspects identical to the LHC collimators

Movable devices in the LHC beam

Almost the same requirements for vacuum and RF

Close to the beam operation ~ 10σ

Same Engineering Team (TS-MME group at CERN)

Same movements (motors, resolvers, positioning detectors, drivers)

Same controls hardware/software through the LHC Control room

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ROMAN POT DESIGN (5/13)ROMAN POT DESIGN (5/13)

Horizontal Pot : physics, overlap for tracks alignment

Integrated beam position monitor

Interconnection vacuum bellow : bake out and RF

Primary Vacuum

Detector

Thin window

Beam

Secondary Vacuum

Vacuum Chamber

Bellow

Beam

Elias Métral, RLC meeting, 02/12/2005

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ROMAN POT DESIGN (6/13)ROMAN POT DESIGN (6/13)

LHC counterflowbeam

Atmospheric pressure

Compensation System

By pass to the machine

vacuum

Elias Métral, RLC meeting, 02/12/2005

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ROMAN POT DESIGN (7/13)ROMAN POT DESIGN (7/13)

The Roman Pot unit

• Three measurement pots : two verticals, one horizontal

• Integrated beam position monitor

•Interconnection bellow between horizontal and vertical pots

•Vacuum compensation system interconnected to the machine vacuum

• Individual stepper motors to drive the pots

• Adjustable jacks to align the RP unit in the tunnel

Elias Métral, RLC meeting, 02/12/2005

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ROMAN POT DESIGN (8/13)ROMAN POT DESIGN (8/13)2 Roman Pot Units = 1 Roman Pot Station

c

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ROMAN POT DESIGN (9/13)ROMAN POT DESIGN (9/13)

The Roman Pot station in the tunnel

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ROMAN POT DESIGN (10/13)ROMAN POT DESIGN (10/13)

Layout around IP5

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ROMAN POT DESIGN (11/13)ROMAN POT DESIGN (11/13)

Roman Pot Parameters

80

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ROMAN POT DESIGN (12/13)ROMAN POT DESIGN (12/13)

0,000

0,100

0,200

0,300

0,400

0,500

0,600

0,00 0,05 0,10 0,15 0,20 0,25 0,30 0,35 0,40 0,45 0,50

)( h(t) tsftc

The pot and the thin window

Optimal thickness

50mm

124mm

Thin window

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ROMAN POT DESIGN (13/13)ROMAN POT DESIGN (13/13)

• One Prototype of the Roman Pots has been installed and operated in the SPS during the 2004 runs,

• Installation in the sextant 5, sector 530

• Counting Room on surface in the blg.BB5

• Test Roman Pot mechanics, controls and cooling in a realistic beam environment

• Study RF influence of the beam bunch structure on the silicon detectors and their electronics

• Study trigger capability of the silicon detectors with the VFAT trigger chip.

Counting Room

Access Point

Roman Pot Location

Roman Pot tests in the SPS with coasting beam

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RF ISSUES (1/2)RF ISSUES (1/2)

Summary

• Beam coupling impedance of RP without ferrites: 1200 ZL/n 18 m @ 740 MHz resonanceQ P 200 W

• Good improvement with ferrites (factor 1/5)ZL/n 3.6 m Q P 40 W

• Ferrites included into the new RP design

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RF ISSUES (2/2)RF ISSUES (2/2)

Ferrite

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VACUUM ISSUESVACUUM ISSUES

Synchrotron radiation is the main gas source (referring to a paper by FZ: There is indeed SR in the outgoing line of the beam as well, due to reflection along the beam pipe)

Bakeout (150o C) mandatory NEG coating on the RP chamber (requires activation at 200o C)

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PLANNING AND INSTALLATION (1/3)PLANNING AND INSTALLATION (1/3)

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PLANNING AND INSTALLATION (2/3)PLANNING AND INSTALLATION (2/3)

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PLANNING AND INSTALLATION (3/3)PLANNING AND INSTALLATION (3/3)The installation procedure

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ATLAS ROMAN POTS AT IR1 (1/3)ATLAS ROMAN POTS AT IR1 (1/3)

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ATLAS ROMAN POTS AT IR1 (2/3)ATLAS ROMAN POTS AT IR1 (2/3)

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ATLAS ROMAN POTS AT IR1 (3/3)ATLAS ROMAN POTS AT IR1 (3/3)