Status of the Muon Alignment System Muon Alignment Group Muon IB December 11th, 2012

Status of the Muon Alignment System

Muon Alignment Group

Muon IBDecember 11th, 2012

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Status of the Track-based AlignmentStatus of the Upgrade on the Hardware-based Barrel

Alignment Issue with the Hardware-based EndCap Alignment

Outline

Zoltán Szillási (ATOMKI) Muon IB, November 29th, 2011

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CMS tracking alignment workflow1. Update Tracker geometry

recently released with 2012 A+B data

2. Update Muon Global Position Record (GPR) optimum position of Muon system based on reconstruction performance

3. Update Muon geometry with new Tracker and new GPR run track-based algorithm over 2012 A+B data

Muon Geometry was updated in November 2012• DT and CSC chambers aligned with respect to Tracker using track-

based algorithm with 2012 A+B collision data slight performance improvement in Barrel (DTs were already aligned with

tracks from 2011 collision data) significant performance improvement in Endcaps (this is first time

individual CSCs are fully aligned with tracks)

Muon IB Meeting, 11 December 2012

Overview

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Resolution:Slight (5% for RMS) improvement in Barrel• DTs aligned well with 2011 data

Significant improvement in Endcaps• CSCs individually aligned with tracks


Muon Reconstruction Performance

Endcaps |

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Resolution of dimuon mass reconstruction at Z-peak• STA+STA muons are used• Barrel – no changes• Endcaps – improves


Dimuon mass at peak

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New Muon geometry produced and validated• New Tracker geometry and new GPR are used• Latest CMSSW and 2012 A+B data are used• New Muon geometry is validated

Significant improvement in Endcaps• this is first time individual CSCs are fully aligned with tracks

The new Muon geometry was signed off• New Muon geometry is in Data Base and being validated with all

other updated conditions• Exact description and recipe how to use new Muon alignment and

GPR were announced in AlCaDB hypernews on Nov 27, 2012 06:57 https://hypernews.cern.ch/HyperNews/CMS/get/calibrations/1273.html


Summary

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Produce new MC scenario matching new Muon geometryStudy systematic uncertainties and include them in APEs• Superlayers misalignment

Compare updated geometry to latest HW geometry• check twist effect

Repeat Muon alignment workflow including 2012 C data• following Tracker geometry update


Plans

8Zoltán Szillási (ATOMKI) Muon IB, November 29th, 2011

HW Barrel Ali Plans in LS1

ie. As soon as a wheel opens, we have to remove all MABs and transport them to the Alignment Lab

In the lab: new targets and calibrations (both for Barrel and Link) In the lab: store the MABs safely Meanwhile in UXC: repositioning the BoardPC and recabling in the

shadow of other activities MABs are to be re-installed at the end of other activities right

before wheel closed PHOTOGRAMMETRY!!! It takes several hours (~ d/wheel). On

MABs we will need everywhere, but will need on chambers that moved, too.

AR will be removed before the arrival of the new beampipe and be reinstalled when ready – PG needed!

Alignment goes first and returns the last!


Reinforcement of measurements in Sector 13 & 14 The reconstruction error for rotZ of MB4 twin

chambers are higher than the other MB4 chambers.Reason: those chambers can seen only from one side

Solution: install “Mini MAB” to those chambers. Very similar to the MAB, but it houses only 2 camera.

The proposed positions are seen on the drawing below. Due to several reasons (blocking electronic and cooling cables) it is impossible to put Mini MAB to every twin chamber.

Results of simulation calculation of errors are on the tables. The position calculations shows the worst case, where the chamber can be seen though two other chamber.

With the Mini MABs the alignment precision for these chambers will be better.

Sector 13

Sector 14

Sector 4

Sector 10

X

Position error for YB0_sect13:w/out MM with MMsmicrometer micrometer

phi 27.4 20.4R 1423.8 166.2Z 1511.2 90.1

rot_Z error:

Sect 14 Sect 14 Sect 10 Sect 10

Wheelw/out MM

with MMs

w/out MM

with MMs

mrad mrad mrad mrad2 0.13 0.046 0.11 0.0461 0.11 0.046 0.14 0.0460 0.48 0.045 0.48 0.045-1 0.11 0.046 0.14 0.046-2 0.13 0.046 0.11 0.046

Position error for YB0_sect14:w/out MM with MMsmicrometer micrometer

phi 27.4 7.5R 1423.8 135.2Z 1511.2 70.1

Results of simulation

Cameras identical to those used for chimney-chamber regions

d

Carbon-fiber plate (5mm thickness)

Mini MAB

YB+2 YB+1 YB0 YB-1 YB-2

S4

Proposed MiniMABarrangement:

MAB

MiniMAB

S13S10

S14

rot_Z error:

Sect 13 Sect 13 Sect 4 Sect 4

Wheelw/out MM

with MMs

w/out MM

with MMs

mrad mrad mrad mrad2 0.13 0.046 0.11 0.0461 0.11 0.058 0.14 0.0580 0.48 0.056 0.48 0.055-1 0.11 0.046 0.14 0.046-2 0.13 0.046 0.11 0.046


CMS barrel part during installation

Location of the miniMAB (see next page)


MiniMAB location

The miniMAB plate is fixed on rails of the muon chambers(drilling new threaded holes not needed)

The cameras are looking into these passages


MiniMABsShort MiniMAB / Long MiniMAB

• The base material of the MiniMAB is glassfiber (yellow)• The fixation of MiniMAB is not shown in this plan

Gábor Endrőczi


Additional photogrammetry targets/redesign photogrammetry targets on MABs

Motivation:• There was a discrepancy between the track-based and the hardware

alignments both in Z (2mm, scaling?) and phi-like torsion (3mm)• So far we have only indirect ways to test where it comes from• Torsion has gone, but was not solved by muon hardware alignment!

We need a direct external measurement possibility.

What to do?• Install additional photogrammetry target to MABs• These targets are viewable for photogrammetry measurements, when

the detector is already closed.• Only those targets are measurable, which are marked with solid line.

There is a slight chance to measure those target which are marked with dashed line. Impossible to make photogrammetry measurements in those places which are not marked.

How?• Survey group could measure Z coordinates of them (or at least Z

distance)• Precision is around 70 microns (discrepancy, we had ~ 2mm!)• Maybe they can measure phi position as well ? answer for torsion…• If Z-scaling found, its value can be used as a correction later.


Map of Survey points in UXC

• 2011 September TS -- Visual inspection has been done on the possibility on the MAB visibility and mounting of new Survey brackets on the UXC wall

• 2011 December (at B=0) final position of brackets were measured (planned to have some installation, but didn’t happen)


Viewable MABs are for Survey measurements

YB0 -

-1/1

-1/3

-1/5

-1/7

-1/9

-1/11

YB+2

+3/1

+3/3

+3/5

+3/7

+3/9

+3/11

YB-2

-3/1

-3/3

-3/5

-3/7

-3/9

-3/11

YB0 +

+1/1

+1/3

+1/5

+1/7

+1/9

+1/11

YB+1

+2/2+2/4

+2/6

+2/8 +2/10

+212

YB-1

-2/2-2/4

-2/6

-2/8 -2/10

-212

Green – measurableOrange – difficult to measure, but not impossible

• Total Barrel length measurement at Sectors 1,5,11• Partial Barrel length measurement at Sectors 8,11


Final prototype of the Survey Target holder

Final prototype ready.Manufacturing of the large batch is on the way


Evacuation of BoardPC from the gaps

The BoardPC placed between the gaps of the CMS barrel wheels in order to be close to the MABs.

These PCs control some part of LEDs and digitalize and analyze the images of the cameras of MABs

They are unreachable when the CMS wheels are closed. CMS barrel wheels was open last time in the beginning of 2008 and they are not expected to be open more frequently after LS1.

After the failures of image grabbers cards of some BoardPCs, we started to think about to evacuate them to the side of the YBs (we had 3 at the beginning, now we have 7).

The possible places to install the BoardPCs has been checked During 2011 November TS.


BoardPC repositioning – draft plan

X1

X2

X3

X4

X5

X1

X2

X3

X4

X5

Far NearPassive wheel (YB±1)Passive MABs (±2/x)

Active wheel (YB±2 & YB0)Active MABs (±3/x & ±1/x)

Place of BoardPC

Probably better place for the BoardPC

Extra:X2 Near A3006 PS modules X4 (YB±1)


BoardPC repositioning – X1

MABs reached• Near side:

YB0 – MAB ±1/11 YB±1 – MAB ±2/10 YB±2 – MAB ±3/11

• Far side: YB0 – MAB ±1/9 YB±1 – MAB ±2/8 YB±2 – MAB ±3/9

Place of BoardPC

MAB in the gap






Passive MAB

Active MAB

Place of BoardPC






Place of BoardPC in YB0

Place of BoardPC in YB±1 & ±2


Status of the Upgrade

• Reinforcement of measurements in Sector 13 & 14 design has been done – proto in weeks; offer arrived Mimmo proposes to mount them on the chamber rails, design of

MiniMAB fixation will come soon necessary Caen 3006 PS already purchased

• Additional PG targets/redesign PG targets on MABs holder prototype ready; order already sent out survey of the external viewing possibilities done next: starting to mount external Survey brackets for external Wheels waiting for offer on targets (Antje)

• Bringing out BoardPCs from the gaps long cable check in ISR done, result positive waiting for Mimmo to measure cable length (needed for the cable order) Mimmo needs to finalize the new BoardPC places


Long-term upgrade plans

Eliminate the single failure point caused by the single frame grabber card on the BoardPCs by changing the cameras to digital. Beside bringing the digitization to the individual cameras, this would allow parallel processing of data and better noise tolerance between the camera and the BoardPC.

We also wondering on changing the BoardPCs themselves since the technology will be more than 10 years old by then and the spare part supply will probably either impossible or unmaintainably expensive.

LS2 idea (not yet a proposal. First let’s get through LS1 ):


Issue with the HW EndCap Aligment System

(Hubert Gerwig, TIG, 2012.10.04)

• No more manpower for analysis on ME• Transfer line might help in understanding the Barrel systematics• Barrel is willing to participate in analysis, provided:

• We can understand the pending calibration issues• Unfortunately, we don’t have resources for redesign + modify

Transfer Plate is in conflict with ME4!

Is the conclusion clear?

25Yuriy Pakhotin (Texas A&M) Muon IB, November 29th, 2011

Back Up

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Current Muon geometry was signed off in February 2011Barrel alignment• DT chambers aligned with respect to Tracker using 2011 collision

data and track-based algorithm• Tracker and Muon System relative alignment implemented as

Global Position Record only tracks in Barrel used, but Endcap and Barrel globally aligned

Endcap alignment• CSC chambers aligned with respect to each other using CSC

overlaps algorithm with beam halo data collected in 2010 with several photogrammetry and SLM constraints muons from collisions used to cross check result with beam-halo, same

result within precision

• Endcap Rings aligned w.r.t. Tracker as rigid bodies global movement and rotation in plane perpendicular to beam line

Yuriy Pakhotin (Texas A&M) Muon IB, November 29th, 2011

Current Muon Alignment

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Software release: CMSSW_5_3_6_patch1Data Sample (2012 A+B re-reco):

• /SingleMu/Run2012A-MuAlCalIsolatedMu-13Jul2012-v1/ALCARECO• /SingleMu/Run2012B-MuAlCalIsolatedMu-13Jul2012-v1/ALCARECO

Input Tracker geometry:• frontier://FrontierProd/CMS_COND_31X_ALIGNMENT• TrackerAlignment_v9a_offline• frontier://FrontierProd/CMS_COND_31X_ALIGNMENT• TrackerAlignmentErrors_v3_offline• frontier://FrontierProd/CMS_COND_310X_ALIGN• TrackerSurfaceDeformations_v3_offline

Input GPR and Muon geometry:• This is starting geometry for Muon alignment iterative algorithm• New GPR obtained with current Muon geometry and new Tracker• Current Muon geometry from Global Tag GR_R_53_V16A

fully track-based Muon alignment signed off on March 2nd 2012

Yuriy Pakhotin (Texas A&M) AlCaDB Meeting, 27 November 2012

Updated Muon Alignment Workflow Conditions

Updatedtracker

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1. Refit reconstructed global muons• new Tracker geometry and new GPR used

2. Select only “good” tracks to use for alignment• transverse momentum: • impact parameter w.r.t. beam spot position: • number of hits in Tracker segment: • normalized for Tracker segment:

3. Propagate selected tracks to Muon system• number of chambers (DT or CSC) with hits per track: • number of hits per aligned chamber:

in CSC: in DT in Super Layers 1 and 3: in DT in Super Layer 2:


Muon Tracks Selection

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Muon residual is difference between measured (with hits) and predicted (i.e. propagated from Tracker) position of the muon in the chamber

Residuals calculated in chamber’s local frame• local residual x = track local x – hit local x• scattering in iron width of residual distribution• chamber misalignment non-zero mean of distribution


Muon Residuals

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Angle-displacement correlations for tracks are not usedFor DT: use and residuals, align local , and

For CSC: use residuals, align local and

NOTE: Muon chambers aligned independently


Residuals and aligned coordinates

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Superlayer profiles example before and after δφz SL1&3 corrections in a problematic chamber:• Slopes of superlayers become very close

Yuriy Pakhotin (Texas A&M) Muon IB, November 29th, 2011

DT Superlayer Misalignment

plot from Vadim Khotilovich (Texas A&M)

plot from Vadim Khotilovich (Texas A&M)

Documents

Status of the Muon Alignment System Muon Alignment Group Muon IB December 11th, 2012