Status of the Roman Pot Project

• reminder • prototyping & testbeam• mechanics & infrastructure• simulation

Hasko Stenzel

ATLAS week

October 2006

Roman Pot status H.Stenzel, October 2006 2

Roman Pots for ATLAS

RP

IP

240m 240m

RPRP RP

RP RP RP RP

PMT baseplate

optical connectors

scintillating fibre detectors glued on ceramic supports

10 U/V planesoverlap&trigger

Roman Pot

MAPMTsFE electronics

& shield

Roman Pot Unit

Roman Pot status H.Stenzel, October 2006 3

testbeam: October 3-18

Purpose:

Verify detector performance observed in 2005 at DESY (6 GeV e- ) with new(larger) detectors, new ATLAS-type electronics with a high energy beam.

New prototypes:

● 10 planes, U&V, 16 fibres tracking ● 2 planes, U&V, 64 fibres final geometry● 2 overlap detectors, 120 fibres each alignment● trigger scintillator elastic L1

Program:

● hit multiplicity & efficiency● cross talk● spatial resolution & homogeneity ● edge sensitivity & active surface ● alignment performance with overlap detectors● trigger efficiency & uniformity

Purpose:

Verify detector performance observed in 2005 at DESY (6 GeV e- ) with new(larger) detectors, new ATLAS-type electronics with a high energy beam.

New prototypes:

● 10 planes, U&V, 16 fibres tracking ● 2 planes, U&V, 64 fibres final geometry● 2 overlap detectors, 120 fibres each alignment● trigger scintillator elastic L1

Program:

● hit multiplicity & efficiency● cross talk● spatial resolution & homogeneity ● edge sensitivity & active surface ● alignment performance with overlap detectors● trigger efficiency & uniformity

Roman Pot status H.Stenzel, October 2006 4

detector prototypes for testbeam 2006

10 x 2 x 16 resolution studies

2 x 2 x 64 construction studies

2 x 2 x 30 overlaps

Fabrication of prototypes at cern bt PH/DT2 with support from Lisbon (LIP) for fibre machining, aluminum coating, QC testbeam mechanicsand from Giessen for gluing of fibres optical connectors

Roman Pot status H.Stenzel, October 2006 5

QC: Metrology

Fibre ends of 10_2_16after machining at 45º

-136.56

-136.55

-136.54

-136.53

-136.52

-136.51

-136.5

-136.49

1 2 3 4 5 6 7 8 9fibre #

po

sit

ion

of

fib

re e

nd

(m

m)

3u3v5u5v6u6v7u7v9u9v10u10v11u11v12u12v

< 20µm variation from one plate to another

prototype 2005:> 250 µm variation

Roman Pot status H.Stenzel, October 2006 6

overlap detector: new technology

Section to be bent

Preheat from room temp to 85ºC

Bend fibres at 85ºC

Straight section

A. Mapelli

Roman Pot status H.Stenzel, October 2006 7

trigger scintillator

scintillator

photomultiplier

light guide

New design of trigger scintillator with lightguide

coupled to a PMT.

Roman Pot status H.Stenzel, October 2006 8

electronics: final set-up

fibreMAPMTPMF(MAROC)MotherBoardDAQ

Roman Pot status H.Stenzel, October 2006 9

electronics: testbeam set-up

PMF Build Up for testbeam October

HV board

Adapter board

Active board

MAROC chip

R/O FPGA

MAROC R/O chip

R/O FPGA

CERN, Orsay (MAROC) & Lund (PMF & MB)

Roman Pot status H.Stenzel, October 2006 10

The final ATLAS Roman Pot Unit

● Pre-production of one unit at Vakuum Praha

● expected at CERN Oct.31● will be instrumented and tested● review of the tests before

production● possible timescale : 4 units at

CERN April-May 2007

Roman Pot status H.Stenzel, October 2006 11

Pre-production unit

Courtesy of Vakuum Praha

Roman Pot status H.Stenzel, October 2006 12

The final Roman Pot

Overlap extrusions brazed on bottom

Top flange with helicoflex joint

Pumping hole

Rectangular body out of center

Brazing under test S.Mathot (TS-MME)

• Prototyping & production at CERN TS

• Material for prototype & final production arrived Oct.2

• Prototyping Oct/Nov

2006

• final production sync. with Unit procurement

Roman Pot status H.Stenzel, October 2006 13

Infrastructure: Cable installation

Reminder – cabling list:        Quantity

Name Start End Type /side of IP1 Total

Trigger XRP-240 USA15 FLEXWELL Air Dielectric Cable, HF 7/8"

4 8

Data link + TTC XRP-240 USA15 Optical fiber for data and TTC (9 fibers/side)

2 4

LV power USA15 RRs 3x4CEM 1 2

LV power control USA15 RRs ND36 2 4

LV power RRs XRP-240 2x25CEM 4 8

LV power RRs XRP-240 2x4CEM 4 8

HV USA15 XRP-240 Mulcitonductor HV cable, 3kVdc, 4 8

FE controls USA15 XRP-240 EIA/TIA RS485 4 8

ELMB USA15 XRP-240 VE18CAN-1.0 2 4

Motor control USA15 XRP-240 NG18 2 4

Limit switches USA15 XRP-240 NE26 2 4

Resolver USA15 XRP-240 NE18 2 4

Position sensors USA15 XRP-240 NE48 2 4

Overlap detector trigger

XRP-240 USA15 50Ohm signal 8 16

BPMs XRP-240 RRs CMC50 4 8

Roman Pot status H.Stenzel, October 2006 14

Infrastructure: Cable installation

Installation of all cables through UPS galleries is now completed on both sides of IP1● Access to the UPS galleries is not allowed anymore due to the installation and

calibration of the instruments for the geometers.● HV multiconductor cables are to be installed, different path via US to UX,

depending on the location of HV power supplies (US15)

Air-core cables – min. bending

radius of 250mm respected

Optical fibers

Roman Pot status H.Stenzel, October 2006 15

Q4 polarity switch

RR13 Level 1

RR13 Level 0DFBLA

RQ4.L1B2 RQ4.L1B1

inverter 7kA

Christophe Coupat AB/PO

Switch for Q4 quadrupole to change its polarity when switching from normal to ATLAS/Lumi optics.

Base & cabling are completed. Temporary Cu plates ordered, will be installed soonBuying the switch itself can be done later

Roman Pot status H.Stenzel, October 2006 16

Simulation of the LHC set-up

elastic generatorPYTHIA6.4

with coulomb- and ρ-termSD+DD non-elastic

background, no DPE

beam propertiesat IP1

size of the beam spot σx,y

beam divergence σ’x,y

momentum dispersion

beam transportMadX

tracking IP1RP high β* optics V6.5

including apertures

ALFA simulationtrack reconstruction

t-spectrumluminosity determinationlater: GEANT4 simulation

Roman Pot status H.Stenzel, October 2006 17

Simulation of elastic scattering

2

,

2

,

2

2222*

yeffxeff

yx

L

y

L

xp

ppt

t reconstruction:

hit pattern for 10 M elastic events simulated with PYTHIA + MADX for the beam transport

2

sin

effL

special optics parallel-to-point focusing high β*

Roman Pot status H.Stenzel, October 2006 18

acceptance

Global acceptance = 67%at yd=1.5 mm, including losses in the LHC aperture.Require tracks 2(R)+2(L) RP’s.

distance of closest approach to the beam

radGeVTOT

EMa

t

Nf

Cf

5.324106

8

|||| :Region Coulomb

Detectors have to be operated as close as possible to the beam in order to reach the coulombregion!

-t=6·10-4 GeV2

decoupling of L and σTOT

only via EM amplitude!

Roman Pot status H.Stenzel, October 2006 19

t-resolution

The t-resolution is dominated by the divergence of the incoming beams.

σ’=0.23 µrad

ideal case

real world

2*231

ˆ pppt

Roman Pot status H.Stenzel, October 2006 20

L from a fit to the t-spectrum

2

222/

2

22

2

16

14

c

e

t

e

t

cL

FFLdt

dN

tBtot

tBtot

NC

input fit errorcorrelation

L 8.10 1026 8.151 1026 1.77 %

σtot 101.5 mb 101.14 mb 0.9% -99%

B 18 Gev-2 17.93 Gev-20.3%

57%

ρ 0.15 0.143 4.3% 89%

Simulating 10 M events,running 100 hrsfit range 0.00055-0.055

large stat.correlation between L and other parameters

Roman Pot status H.Stenzel, October 2006 21

experimental systematic uncertainties

Currently being evaluated

beam divergence detector resolution acceptance alignment beam optics

ΔL/L ≈ 1.9-2.1 %

missing: background studies (are under way)

total error ≈ 2.6-2.8 %

Roman Pot status H.Stenzel, October 2006 22

conclusion

● testbeam 2006 is starting, preparations in full swing

● new prototypes produced, including overlaps and trigger

● electronics set-up close to ATLAS

● RP units and pot prototypes are under production

● major cable installation effort ● progress on simulations for TDR

● testbeam 2006 is starting, preparations in full swing

● new prototypes produced, including overlaps and trigger

● electronics set-up close to ATLAS

● RP units and pot prototypes are under production

● major cable installation effort ● progress on simulations for TDR