Overview on CMS HPS Proposal. Moveable Beam Pipe status.

Overview on CMS HPS Proposal. Moveable Beam Pipe status.

LEB Meeting 19 July 2012D.Dattola. INFN To

HPS LEB meeting 19 July 2012 2D. D. INFN To/CERN PH UCM

CMS High Precision Spectrometer.

Add new CMS sub-detectors at 220/240 m upstream and downstream of central detector to precisely measure the scattered protons to complement CMS physics program.

HPS2 stations a parted ~10m with Horizontal Moveable Beam Pipe at ~ 240m on each arm.

Detector as close as possible to the Beam: 15 Sigma =1.5mm.

(29mm far during Beam Injection and stabilization)

Option: 1 station at ~220 just after RP4 in collaboration with TOTEM

Each station is composed of:

1) Array of radiation-hard near-beam Silicon detectors with resolution of ~10 m, 1rad

2) Timing detectors with (GasTOF or QuartIC)~10 ps resolution for overlap background rejection

3) Hamburg Beam Pipe instead of Roman Pots

A note on HPS can be found on https://dfs.cern.ch/dfs/Users/d/dattola/Public/HPS        

HPS LEB meeting 19 July 2012 3D. D. INFN To/CERN PH UCM

Available space between the Dump resistors (DQR) and the beam pipes is about 125 mm. We could consider to use the space in between the DQR modules and Q6 and just after the 3rd DQR. Minor impact on existing installation. As option, in collaboration with TOTEM, an unique station might be installed just after RP4

HPS Integration at 240m

View on ~220m zone TRP4 –Q6View on ~220m zone Q6-Q7

HPS LEB meeting 19 July 2012 4D. D. INFN To/CERN PH UCM

• Flatness measured : ±50 mm over full surface and between two pockets.

Moveable beam pipe: Last prototype from 2009. UCL Louvain

BEAM PIPE DESIGN. Prototype from FP420 RD

HPS LEB meeting 19 July 2012 5D. D. INFN To/CERN PH UCM

HPS Moveable Beam Pipe Layout (June 2012)

Detector Box host Quartic or Gastof and Silicon Tracker.

Internal dimensions are: 230 x 510 x 125 (mm)

The enclosed volume is vacuum tight (secondary vacuum or gas filled).

Detector dimension , services and feed trough still to be defined.

• Fixed BPM• Bellows• BeamPipe• Detor Box• Moveable BPM

HPS LEB meeting 19 July 2012 6D. D. INFN To/CERN PH UCM

HPS Beam pipe design –DRAFT-- 2

HPS LEB meeting 19 July 2012 7D. D. INFN To/CERN PH UCM

Beam Pipe v4 design

Aperture d= 58mm

HPS LEB meeting 19 July 2012 8D. D. INFN To/CERN PH UCM

Beam Pipe.

Moveable beam pipe will be internally coated by a high conductivity copper layer as recommended by RF group. Tapered angle is ~20º

A NEG layer can also be considered.

HPS LEB meeting 19 July 2012 9D. D. INFN To/CERN PH UCM

44.57.10.B - ROUND BARS - STAINLESS STEEL (316 LN LOW CARBON) - Cr

Ni 18.12. Mo N

The suggested material for the beam pipe is forged massive bar in 316 LN from CERN

store – 44.57.10.352.9 .

The shape can be cut out by EDM process.

Beam Pipe Material

HPS LEB meeting 19 July 2012 10D. D. INFN To/CERN PH UCM

Ansys FEA

Beam Pipe Ver.2.Von Mises stress. DP=0.1MPa (Max stress= 19.1MPa)

Translational Displacements. DP=0.1 MPa (max def.= 0.017mm)

HPS LEB meeting 19 July 2012 11D. D. INFN To/CERN PH UCM

Effects of beam on collimator’s jaw.

• Thin window” with a thickness of 0,3mm, during operation approach the beam at about 15 sigma (~1,5mm). It is not in the shadow of collimators. For safety reason a box can

completely surround the “thin window” region over the vacuum chamber protecting the LHC beam pipe vacuum in case of accident. A rough vacuum 10^-3mbar, or ,even just an enclosed volume, filled by nitrogen at atmospheric pressure would drastically help reducing effect from beam

loss (see effects of beam on collimator’s jaw slide). Detectors itself doesn’t need vacuum.

Detector Box

HPS LEB meeting 19 July 2012 12D. D. INFN To/CERN PH UCM

Beam Position Monitor on Moveable Beam Pipe.

2 BPM are foreseen to monitor the Moveable Beam Pipe position wrt beam. The first one is on the fixed Beam pipe and the second move with the Movable Beam Pipe. In the figure a body of BPM used in LHC beam instrumentation is adapted. This body has been suggested as the most likely adaptable to our scope (FP420).

Finalization of Beam Pipe design require also definition of this component. We need to re-establish contact in BE/AT group .

HPS LEB meeting 19 July 2012 13D. D. INFN To/CERN PH UCM

HPS Moveable Beam Pipe. Movement.

Motor and controls hardware(lvdt, stops) are assumed to be the same of collimators.

Some aspects still require work eg: Auto retraction in garage position in case of hardware or control failure might require additional feature on the present preliminary layout. Interaction needed with collimators working group.

Moreover, a preliminary risk analysis is necessary to assess the validity of the proposed

solution.

HPS LEB meeting 19 July 2012 14D. D. INFN To/CERN PH UCM

Bellows proposed for FP420.

Mechanical and RF Compatibility to be verified.

Bellows

AFP LHC Standard bellows test.

(courtesy of Giancarlo Spigo )

HPS LEB meeting 19 July 2012 15D. D. INFN To/CERN PH UCM

Specification:• Stainless steel AISI 316L or AISI 316Ti.• Vacuum tight.• Bake out to 250 C• Lateral offset +/- 31mm• Quantity 16 pcs.• Life cycle expectancy >>10.000 cycles (in this

dimensioning >100.000 cycle)

Bellows with intermediate tube allows extensive lateral movements minimizing stress. In this studio dimension allows to add a RF screen.

In case RF screen result not necessary, internal diameter can be reduced to 96mm; 93mm; or 85mm. Reducing diameter the mechanical characteristic and life cycle expectancy are not negatively affected, we can keep behavior or even increase it reducing the size.

Alternative proposal. Studio following Witzenmann Metal Bellows Manual guidelines

HPS LEB meeting 19 July 2012 16D. D. INFN To/CERN PH UCM

• Studies on Beam Pipe compatibility with LHC operation, vacuum, beam impedance, RF and safety

• Define and design final layout of Beam Pipe, Detector box, BPM, Motorization and controls, Bellows and ancillaries. Integration of various components need interaction among various groups and expert.

• Collaboration with AFP would be very helpful. Beam pipe requirements for AFP and HPS seems to be different. We could consider as common components at least bellows, motorization and controls.

• Alignment Strategy • If the proposal will be endorsed by management, a

possible (ambitious) plan is to install at least mechanics and services of 1 station by the end of LS1.

Thanks.

Next Steps.