24/03/99report to lhcc referees muon group status report outline: muon filter - new geometry -...

24/03/99 Report to LHCC Referees

Muon Group Status ReportOutline:• Muon Filter

- New Geometry- Support System

• Optimisation Studies- Pad, Strip and Pad/Strip algorithms- Background Model

• Detector Technology and FE-Electronics Studies- MRPC R&D (CERN, UFRJ Rio)- RPC and TGC R&D (Rome I, Rome II)- CPC and WPC R&D (PNPI, CERN)- FE-Electronics (Cagliari, CERN, UFRJ Rio)

• Summary of Activities and Milestones for 1999


Motivation: Iron blocks from WANF will be used to build the muon filter Dimensions: • Muon shield 1 has 30 cm thickness in TP• Muon shields 2-5 have 70cm thickness in TP• Iron from WANF has 40cm and 80 cm thickness

Consequences:-› The proposed new configuration has the same number of nuclear interaction length: 23 -› The particle fluxes in M2 will be slightly higher-› There will be less multiple scattering between M1 and M2 better PT measurement (?)

New Muon Filter Geometry


Muon System Support StructureStatus:

Preliminary studies have been done by S.Karpinnen in 1997/1998 (Technical Note EST/LEA/98-02)

Constraints:• Rails of DELPHI - endcap should be re-used if possible• Clearance on cryogenics side is only 9.4m from BP at present, thus right

part of muon stations cannot be moved out fully-› ~12m clearance would simplify access to muon chambers significantly

Consequences:-› Stations should be movable independent of absorber and of each other-› Chambers should be mounted on a frame hanging from the top -› Cables will be guided via the top

Conceptual design for support structure under study in collaboration with infrastructure group


Electronics and CablesLocations for electronics:• Boards with a kind of ASD chip on the chambers• Majority-logic and synchronization unit on the sides of the stations• Muon Trigger- and- DAQ-Electronics in the Control Room

Engineer from Cagliari is working on overall design for Muon FE-electronics


Optimization StudiesGoal:

Significant reduction of electronics channels without deterioration of the physics performance

Pad based algorithm :Optimization result

• ~15% less physical channels than TP• ~25% less logical channels than TP• physics performance:

(cf. presentation of 22/10/98)

Pad Layout 1% MB

BX 2% MB 3% MB

TP (default) 7.9% 12.1% 14.1%

Optimised 8.8% 11.6% 13.6%

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Optimization StudiesGoal:

Significant reduction of electronics channels without deterioration of the physics performance

Pad based algorithm :Optimization result

• ~15% less physical channels than TP• ~25% less logical channels than TP• physics performance:

(cf. presentation of 22/10/98)

Pad Layout 1% MB

BX 2% MB 3% MB

TP (default) 7.9% 12.1% 14.1%

Optimised 8.8% 11.6% 13.6%

Title:mupd_comp_3.epsCreator:HIGZ Version 1.25/05Preview:This EPS picture was not savedwith a preview included in it.Comment:This EPS picture will print to aPostScript printer, but not toother types of printers.


Optimization Studies

Rejection of Minimum-Bias-Events is achieved by:• PT - cut between 1-2 GeV • Choice of field of interest (FOI) -› implicit cut on muon momentum

So far, only one x-FOI and one y-FOI per station has been usedImprovement of performance possible with several FOI per station

L0-Muon-Trigger:


Optimization StudiesField of Interest Optimisation:• optimal FIOs per region change with required Minimum Bias retention • improves physics performance

Performance for optimal pad geometry(as presented before)

Pad Layout 1% MB

BX 2% MB 3% MB

TP (default) 7.9% 12.1% 14.1%

Optim.(#ch) 8.8% 11.6% 13.6%Optim.(FOI) 10.0% 12.4% 14.3%



Optimization StudiesField of Interest Optimisation:• optimal FIOs per region change with required Minimum Bias retention • improves physics performance

Performance for optimal pad geometry(as presented before)

Pad Layout 1% MB

BX 2% MB 3% MB

TP (default) 7.9% 12.1% 14.1%

Optim.(#ch) 8.8% 11.6% 13.6%Optim.(FOI) 10.0% 12.4% 14.3%

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Optimization StudiesStrip based algorithm : Improvement of physics performance due to finer granularity using strips ~25% reduction of physical and ~50% reduction of logical channels possible Simplification of chamber construction Less robust against background

Layout:

one pad plane to resolve ambiguities


Optimization StudiesStrip based algorithm : strip layout is more sensitive to background

than padsstandard background backgroun

d x2

background x3


Background StudiesBackground Model :• Realistic description of the background is mandatory to

- determine the performance of the L0-Muon-Trigger (including safety factor)- choose a technology for the muon chambers

• Current Model is - based on old detector and beampipe description and low statistics- providing only additional hits in stations 2-5, no particles

• Updated model will take into account- better description of beampipe and its shielding- muon system geometry, chamber description and digitization- new physics generators- neutron efficiencies for gas containing H2 …

Production based on updated model will start in May 1999


Optimization StudiesCombined Pad / Strip layout :• Pads in inner part of muon stations solve problem of high occupancy • Strips in outer part allow significant reduction of physical / logical channels

and provide better granularity -› improved physics performance• Algorithm for combined Pad / Strip layout with FOI optimization ready



Optimization StudiesTrigger implementation:• Several geometries have been looked at from trigger implementation point of

view, running the fast identification and the theoretical algorithm • Combined pad/strip layout with strips in outer part of stations 2-5, pads in

station 1and inner part of stations 2-5 - same granularity as TP- 33% reduction of logical channels

Algorithm efficiency for B X:

Note sensitivity to background

Scale factor forbackground.

TP-layout Pad/Striplayout

x1 100% 99%x2 87% 86%x3 70% 68%


MRPC R&DParticipants:

CERN, UFRJ Rio groups

Status:• First prototype (30cm 30cm) :

- studied in testbeam in various configurations- ongoing tests with cosmic rays - timing properties are according to expectations (cf. presentation of 22/10/98)

- rate capability of a few kHz/cm2 has been achieved - problems with chamber noise at high rate not yet under control

• Second prototype (230cm 130cm) :- Construction techniques have been developed- Chamber soon ready for tests with cosmics (beam tests scheduled for May)


MRPC R&DTestbeam Results: Title:mrpc_effi.epsCreator:HIGZ Version 1.25/05Preview:This EPS picture was not savedwith a preview included in it.Comment:This EPS picture will print to aPostScript printer, but not toother types of printers.

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time walk: ~ 1.5ns/kV

time resol.:1.5ns


MRPC R&DStatus:• FE-electronics board with better control of threshold has been designed

- PCB is in preparation- continue tests with ASD8-B from UPenn

• Gas system with mass-flowmeters available for this years beam tests-› Improved control of gas mixture

Plans for this year :• Test small prototype with 4 0.7mm gas gap, plates of lower resistivity

(a few 1010 cm) and new FE-electronics board end of April at PS-› Allows to operate chamber at lower HV; expect improved performance

• Test large chamber end of May with SPS-beam• Test small chamber in GIF end of June


RPC R&DParticipants:

Rome II RPC construction done in Italian industry (as for ATLAS and CMS)

Status:• Prototype of Single Gap RPC with

- plates of low resistivity (8 109cm)- 48cm 48cm active area - 16 strips with 3cm pitch along x- 16 strips with 3cm pitch along y- standard electronics with 10 30 amplification- gas mixture: C2H2F4, iso-C4H10 , optional: SF6

- studied in testbeam in November 1998


RPC R&DTestbeam Results:

time resolution ~2 ns

1-2% SF6 in gas mixture

no SF6 in gas mixture


RPC R&D

Plans for this year :• Two Double gap RPCs have been produced

- using plates of low resistivity (a few 109cm)- active area of 50cm 50cm and 25 strips of 2 cm pitch- tests scheduled for end of April (PS) and end of May (SPS)- tests in GIF end of June

-› Expect improved performance w.r.t. rate capability and cross talk

FE-Electronics:• Tests with fast GaAs-Electronics (as for ATLAS RPC) foreseen in August


TGC R&DParticipants:

Rome I TGC construction done in collaboration with G.Mikenberg

Status:• Simple TGC prototype has been tested in November 1998 at the PS - 1.8mm wire spacing

- gas mixture: CO2 and n-C5H12

TGC charge distribution TGC time distribution


TGC R&D

Plans for this year :• Two twin TGCs have been ordered

- sensitive area: 25cm 80 cm- wire spacing 1.8mm, staggered- Resistance of graphite layer: ~200 k �

- tests foreseen in July at the SPS


CPC R&DParticipants:

PNPI St.Petersburg

Status:First prototype with pads of different size has been constructed at PNPI together with its FE-Electronics and tested in November 1998 at the PS - wire spacing: 2mm - preferred gas mixture: 30% CO2 , 60% Ar , 10% CF4


CPC R&DResults : Time distributions• Prototype performed very well• Testbeam measurements are in good

agreement with MC-simulations• No deterioration up to very high rates• cross-talk to neighbouring pads: ~5%

charge distribution


CPC and WPC R&DPlans for this year :• Continue studies with CPC prototype• Work on backup-solution for outer region: WPC / WSC

(Proportional chamber with simple construction) - sensitive area: 16cm 150 cm- 2 gaps of 5mm each, wires staggered, spacing 1.5mm - tests foreseen from May onwards at the PS and SPS


Activities and Milestones for 1999Optimization Studies:• propose optimal and realistic layout May • study robustness against background June • check feasibility of trigger implementation June

-› Decide on muon system layout July

Detector Technology and FE-electronics Studies:• first round of tests for various technologies April-July• preliminary decision on technologies August• second round of tests for selected technologies Aug.-Nov.• test of FE-chip candidates (Lab and testbeam) April-Nov.-› Choice of technologies December


Activities and Milestones for 1999Optimization Studies:• propose optimal and realistic layout• study robustness against background• check feasibility of trigger implementation

-› Decide on muon system layout July

Detector Technology Studies:• first round of tests for various technologies• preliminary decision on technologies• second round of tests for selected technologies • test of FE-chip candidates (Lab and testbeam)-› Choice of technologies Januar 2000

24/03/99report to lhcc referees muon group status report outline: muon filter - new geometry -...

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