MU Barrel Workshop 1

CMS m Alignment Status and

Goals for 2011

24-Feb-2011

2

2011 Alignment Goals• Understand systematic differences between HW / TB barrel alignment• Provide realistic APEs• Alignment of barrel (+ endcap?) using Stand-Alone muons• Complete/update endcap HW alignment: SLMs + TLs• Merge HW and TB alignment information in endcaps + barrel• Study of MB1-ME12 overlapping tracks

• check relative YE-YB alignment• Several others regarding technical issues

• Optimization, automation, merging of HW system DAQs etc

24-Feb-2011 MU Barrel Workshop

MU Barrel Workshop 3

Muon Alignment: current status

before alignment after alignmentSample plot from endcap alignment

Barrel alignment comparison (exaggerated

by a factor of 200)

Two alignments for comparison: track-based and hardware They agree on the mm-scale

positions of chambers, but differ by a “twist” of 2 mm amplitude: sin(phi) x eta bias in track pT for TeV-scale muons (~0.2 c/TeV)

Resolving this is our highest priority (several ongoing studies)

Current geometry from hardware

Endcap aligned using a combination of hardware, beam-halo, and collisions tracks

Beginning new project to supply APEs (misalignment-dependent weights for track-fits) to improve TeV-scale track-fitting

Status shown by POG during Physics Week

24-Feb-2011

MU Barrel Workshop 4

Muon Alignment: projections and plansProjections: Plans:

pT > 15 vs 20 GeV/c → 30% effect Best track-based resolution for first-station chambers Reaches systematic limit at ~1 fb-1

Systematic issues (e.g. “twist”) do not scale with integrated lumi Continue working with comparisons of TB collisions, cosmics/BH, and HW

24-Feb-2011

This is very conservative:0T vs PG indicate ~500 mm

Note: barrel ali with collision muons ongoing

Status shown by POG during Physics Week

MU Barrel Workshop 5

impacts(at 0T) Jan’10 Oct’10 Jan’11

LD->TPs(out of 12) 10 10 10

LD->MABs(out of 12) 9 4 8

AR->TPs(out of 6) 4 2* 4

After incident. No Signal.

After reorientation. Good Signal.

*: 2 sensors at B=0T; only 1 at B=3.8T.

In January 2011, the Link team performed a reorientation of the LD-, in order to recover laser impacts.

• Soon after the detector closing in January 2010, the negative Link Disk structure (LD-) suffered an impact.

• This impact rotated the LD- around Φy ~-3 mrad and around Φx ~+1 mrad. • As a consequence of the LD incident, some laser hits were lost:

Link Disk (-) readjustment

24-Feb-2011

MU Barrel Workshop 6

LD-Position(mm) Angles(mrad)

X Y Z Φx Φy ΦzJan-2010 -0.83 -2.95 -6691.2 -0.47 -0.87 -0.68Oct-2010 0.30 -2.80 -6691.6 0.48 -3.01 -1.03Jan-2011 -0.48 -2.56 -6690.6 -0.52 0.10 -1.70

LD- Prediction using

Inclinometers (mrad)Φx Φz

Oct-2010 0.21 -1.06Jan-2011 -0.57 -1.64

DATA INFOJan-10: First data after closing in January 2010 before field. Immediately after, the LD- was displaced physically (LD incident).Oct10: Data at B=0T after several magnetic cycles and after LD- incident.Jan11: Data after reorientation of LD- by Link Team at B=0T.

LD- reconstruction (inside YE-1) using laser impacts in 3 different periods all at B=0T.Note: we purposely remove inclinometer data from fit for independent cross-check purposes (not our standard reco)

LD- readjustment: -z recovered!

24-Feb-2011

• Since 10-February, full field back again: B=3.8T• After ramp to 3.8 T, still 4 out of 6 AR- lasers reach YE-1 !!

(see Zoltan’s talk)

MU Barrel Workshop 7

Barrel + Link HW Alignment @ 3.8 T

 New barrel alignment at 3.8 TSee Zoltan’s talk

New link alignment at 3.8 T Benefits from recovered

negative sideBoth use recent 3.8 T data taken

simultaneously (on Feb. 13, 2011)These alignments are very new

(from this week) and are therefore still preliminary

24-Feb-2011

MU Barrel Workshop 8

TB-HW “Twist”

24-Feb-2011

• Systematic difference between HW and TB barrel alignments• Overall 4-5 mm end-to-end effect in z and rf• Dominant source of alignment uncertainty! Priority: highest

People: ALLTimescale: unknown

MU Barrel Workshop 9

• 2010 – a relative "twist" is observed in the barrel in track-based muon alignment with respect to hardware muon alignment.

• Feb 2011 – a new "twist free" tracker alignment produced by Tracker DPG

• 20 Feb 2011 – the twist is gone with latest track-based muon alignment with the “no twist” tracker. Muon pT =15 – 200 GeV, multiple refit of global muons.

“Twist-free” Track-based Muon Alignment

HW vs TBoldTK “TWIST”

HW vs TBnewTKNO “TWIST”

Aysen Tatarinov, Texas A&M

24-Feb-2011

(animated slide)

10

“Twist-free” Track-based Muon AlignmentAysen Tatarinov, Texas A&M

Detailed discussion at tomorrow’s m ali: stay tuned!

HW vs TBoldTK “TWIST”

HW vs TBnewTK NO “TWIST”

2D view of station 1

Summary• The “twist” is gone with the latest tracker alignment• The agreement with the hardware based alignment has substantially

improved• Although some more polishing to be done before producing a new

quality alignment• It is clear now that comparisons of track-based and hardware muon

alignments is a good tool for detecting possible tracker deformations • A valuable feedback and a cross-check for the tracker people

24-Feb-2011 MU Barrel Workshop

MU Barrel Workshop 11

APEs

24-Feb-2011

Priority: highTimescale: 1 month

POG asks for realistic APEs (for DTF)For each d.o.f. of each chamber

For TB: from covariance matrix For HW: under study

Work is ongoing For HW: take at zeroth order residuals from PG comparison at 0T

(subtracting PG uncertainty) (different APEs for different DTs, for example station 4, special DTs not well reconstructed, DTs close to lost MAB, etc etc)

Collective wheel movement factored out Global z uncertainty has a “constant” term and a linear term which

scales with |z| because this uncertainty is cumulative for HW alignment

For all chambers: GlobalPosRcd should include APEs as well: this way there is no need to convolute muon alignment APEs with errors in the TK-MU relative positioning

MU Barrel Workshop 12

Alignment using SA Muons

24-Feb-2011

• Important test, independent from tracker• See status talk by Luca today (24-Feb-2011)

Priority: mediumTimescale: 3-6 months

Some comments Manpower not great: only one person After/If barrel alignment is successful, no reason not to extend

it to endcap (endcap is harder with cosmics, and few high energy collision muons so far…)

It would be desirable to find one more person to work on extension to endcap when/if the time comes

MU Barrel Workshop 13

Endcap HW Alignment

24-Feb-2011

• We need to update SLM alignment• We must finish transfer line analysis• Merge SLM+TL+Link into one endcap HW ali

Priority: medium Timescale: unknown

Some comments Manpower concern: SLMs have only ½ FTE TLs have only ¼ FTE Who will do this in the longer term? Are the responsible

institutions going to ensure a proper transfer of knowledge and tasks?

What are realistic timescales in the short term for these tasks?

MU Barrel Workshop 14

Merge TB and HW alignment info

24-Feb-2011

• Current barrel situation: two separate alignments now agree reasonably well (to be quantified, detailed discussions will start tomorrow). We can now start thinking about combining to get the best of each

• Current endcap situation: attempts to unify HW and TB are ongoing

Priority: mediumTimescale: 6 months?

MU Barrel Workshop 15

MB1-ME12 overlapping tracks

24-Feb-2011

• Look at tracks overlapping MB1 and ME12 chambers • Extrapolate MB1 track into ME12, check out residuals• Powerful to determine MB – ME relative positions• Use TB-aligned barrel and endcap• Use DTs and CSCs anchored to Link MABs on one single side

Priority: mediumPeople: ??Timescale: 2-3 months?

Some comments This task does not yet have a person assigned to it

MU Barrel Workshop 16

MU-TK cross-alignmentDetermine the MU position with respect to TK using global tracks

New MU-TK cross alignment will be presented tomorrow at m ali meeting by Alexander Spiridonov

Barrel+Link will soon provide new alignment X-alignment should find small corrections to barrel position if the barrel is

anchored to link MABs Because Link MABs are referenced to Ars which are placed at PG and TK GPR is

also taken from PG  Input:

New internal “twist-free”tracker alignment Current (not 2011 yet!) internal optical barrel alignment 70K global tracks

TK GPR: Was using x,y,z from PG = (-0.09, -0.11, -0.17) cm, but all rotations were 0 Now includes non-zero rotations:

Rz from PG (large, -1.2 mrad) and Rx (300 mrad) from B-field vs TK axis studies This should in turn make the MU GPR rotations (especially Rz) smaller

Output: Global Position Record for Muon System

24-Feb-2011

17

SummaryRecovered link functionality on –z side after shutdown intervention:

link is better than ever at 3.8 T Also additional improvements such as including inclinometer information

New (preliminary) link+barrel HW alignment for 2011 at 3.8 TBarrel HW-TB twist, our topmost priority, seems to have been solved

Much improved agreement between the two methods Opens up a few more lines of work such as

merging of HW and TB in barrel Using HW-TB differences to constrain TK alignment Aside: maybe a few changes to current alignment section of performance paper

(this is why I asked for a 4-day extension)Realistic calculation of APEs for barrel (HW and TB) and endcap (TB)

is ongoingBarrel alignment with collision muons is ongoing

Expected performance as a function of ∫Ldt knownBarrel alignment using SA muons is progressing wellMU-TK cross alignment procedure well established (and fast)Merging of HW endcap alignment with TB endcap alignment is

ongoing

24-Feb-2011 MU Barrel Workshop

We are in better shape than ever