A dissertation presented to obtain the degree of Doctor of Philosophy in Physics

1. Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas A dissertation presented to obtain the degree of Doctor of Philosophy in Physics Marcos Fernández García

3. After LEP the next energy scale to explore lies within the TeV range 7 on 7 TeV proton beam collisions 8 straight sections (528 m/section) 2 High L collision points CMS & ATLAS 2 Lower L ALICE Pb & LHC B 2835 bunches, 1011 particles/bunch, 25 ns Xtime, 20 int/crossing

4. International collaboration  150 institutions  2000 scientists One of the 2 general purpose LHC detectors Design presented first at LHC Workshop (Aachen, 1990) DESIGN FEATURES 1) Very good lepton (,e) measurement 2) Robust secondary vertex 3) High hermeticity

5. pb-1 5 pb-1 5 SM Higgs B physics:  Mass value not predicted by theory 114 < MSMH < 236 GeV (95 % C.L.) CMS goal is to scan up to 1 TeV Higss masses  CMS will study CP violation, B0s mixing, rare decays ... SUSY searches:  Promising signatures: SM known to be incomplete (mH divergence, no unification of forces…) SUSY solves these problems. In the MSSM the Higgs sector extends to 5 particles. Again, most important signatures are leptons and b-quarks. • H  (MH  150 GeV) • Demands 1 GeV and 0 rejection • H W+W- (130  MH  200 GeV) • Central distribution of gg scattering • than bckgd. • 5 after 5 fb-1 • H  ZZ* (MH 2mZ) • Detection combines • CT, Calorimeters, -Chambers • H  ZZ (MH > 2 mZ) … and yet able to explore other searches beyond the SM as Technicolor signals, new gauge bosons, excited quarks...

6. pT measurement related with bending: Radious of curvature  can be obtained from the measurement of the sagita after traversing distance d: Tracking detectors involved: Silicon and Muon spectrometer

7.  New layout after Dec. 1999  Mechanically divided into TIB: 4 layers, shell mechanics TOB: 6 layers, rod mechanics TEC: 9 big, 3 smaller disks, panels  Double sided modules faked using two single sided, (rear tilted 100 mrad)

8.  Multiwire proportional chambers. Avalanche developed in a wire induces on cathode an electrostatic charge.  Seven panels, wires doubly wounded in three.  sCSC= 75 mm ME1, 150 mm rest  Identification, trigger and muon momentum measurement Layer = cells array Superlayer = 4 layers Muon Chamber = 3 superlayers swire < 250  100 mm swire plac = 300 mm schamber = (100 mm Rf, 150 mm Z)

9. Three methods to measure the momentum: CT alone, MS + interaction vertex, CT + MS MS + interaction vertex CT + MS

10. R = 150-350 m, MB1-MB4 R = 75-200 m, ME1-ME4 R,Z coordinates at the mm level Muon chambers rest on return iron yoke Expected cm movement when magnet on/off T changes, humidity Detectors position changes  Positon need to be monitorised Maximum misalignment to avoid degradation on pT measurement

11. CMS alignment is organised in TK alignment, Muon system alignment and Link system Alignmenttasks:  Internal TK alignment  Internal Muon Barrel alignment  Internal Endcap alignment  Link system to relate TK and Muon Spectrometer

12. placement = 50 m, Si-mod  100 m + Track fits = 10 m TKal Tasks of TK alignment:  TKAL uses Si-modules as alignment sensors and Tracks to achieve 10 m align. accuracy Independent alignment of Ecs. Monitoring 50% petals, rest using tracks overlap Relative alignment of ECs  Relative alignment of ECs w.r.t. Inner and Outer Barrel Provide Link with 62 beams of known position and orientation

13. Expected Barrel Alignment performance Within Sector  < 150 m R Adyacent Sectors <210 m R Measures position of chambers w.r.t each other  MS monitoring wrt network 36 MABs. 6 RZ active planes, 6 passive planes Connections by light sources in frames Precalibration Outside Fiducials Sources Wires 60 m R 300 m Z 50 m

14.  (,R,Z) alignment relies on MAB rigidity. Connection to CT via active MABs  Simulation: alignment error  CSC resolution ( pT > 100 GeV) R R  Z Z   Z R  (,R) transfer via Transfer Line  3 SLM perpendicular to TLs Rest through  overlap  Z measurement: Proximity sensors  R measurement: Cable extension linear potentiometer  Simulation: CSC= 200 m, rest through  overlap

15.  Transports CT coordinate system to Muon Chambers  Six 1/4 planes every 60 degrees  reference of each barrel sector to CT  Layout accommodates to detector geometry  2 laser sources generate 3 beams each  Light Beams seen by 2D sensors  Periscopes embed beam within TK   coordinate measured using tiltmeters  Proximity sensors coupled to CF tubes used for (Z,R) measurements. Tubes protect light path  System performance guaranteed once all sensors in range  System can be switched on/off 2D (X,Y) Z Proximity Full Simlation with reasonable set of inputs gives R 150 m  Tiltmeters

16. Sensors 2D position sensing detectors: ALMYs Tiltmeters for  measurement Proximity sensors Temperature sensors Tracker Si-modules Optomechanical Components Light sources Periscopes ME1/1 Transfer Plate

18.  2D signal integration allows position calculation CMS and ATLAS alignment systems request 5 m, 5 rad  Easy to integrate solution for multipoint alignment problems  Spot position calculation: Gaussian mean or Centroid. Equivalent for true Gaussian beams  Characterization comprises: Linearity studies, Deflection, Ageing 2D mapping of relevant magnitudes needed  64  64 crossings act as 64+64 strip photodiodes  Signal is integrated by each strip

19. Set I: Santander, commercial, 7 sensors Set II: Batches of sensors tested 13 sensors Set III: 15 sensors, coated Set IV: 10 sensors, coated, commercial electronics L-shaped granite bench ground floor isolation, UC dark room, T=0.1 C Experimental Facilities: Massive granite bench Shielded Setups MPI High T stability Laser diodes or HeNe Very Good poinintg stability Very stable setups, Shielded meas.: Very Good S/N

20. Different Systematics from line to line Platform effect discarded Different sensors Different patterns We call it: INHOMOGENEITY PATTERN We call it: DEFLECTION PATTERN Oscillations on top of linear slope Different lines Different patterns No correlation between linearity and deflection patterns

21. Spatial resolution: residuals Minimum displacement sensor can resolve x  4.1 m y  4.6 m SET II x  7.1  3.0 m y  5.8  1.8 m Coated sensors SET III x  4.0  0.4 m y  2.9  0.7 m Coated sensors SET IV x  4.4  1.0 m y  13.7  7 m

22. WEDGE Layer = Interferences Curved substrate = Slope CURVED SUBSTRATE

23. Bulk deflection: n,d Slope: Substrate curvature Oscillations: interference  < 175 rad   20 rad Interferential patterns 2D scan  calibration Matrix xy Procedure New measurement corr  current - xy TRANSMITANCE  = (21.9  1,1)% @  = 632.5 nm  = (57.2  1,6)% @  = 686 nm Correction D > 1 m 5 rad required

24. 1600 precalibrated nodes 12 parameters SET II x  4.6  1.9 rad y  4.8  2.0 rad SET IV Coated sensors x  4.0  1.6 rad y  6.5  1.2 rad Alternative correction method: Provided amplitude of oscillations is small, a quadratic fit of the “deflection” distribution is a good correction method.  = a x2+ b y2+ c xy+ d x+e y+ f Even more valid for coated sensors, were patterns show no oscillations Coated sensors SET III x  2.2  0.6 rad y  2.2  0.7 rad

25. G ph   till Effects reversible by annealing Nr(till)=N0+N++N- (e-,h) creation  Power (G) New d.b. inhibited by ner of existing ones (self limiting) Nr3(till) = Nr3(0) + C(At) G2 till Note: Csw independent of incoming photon energy 600,1000 nm

26. Systematic tests performed on 4 coated sensors P = 0.9 mW (115 mW/cm2),  = 780 nm Scanned before the test and every 24 hours PR reduction 2-3% (5 m) for500 hours Double CMS or ATLAS operation time Fit to SW theory performs well Ageing plus daylight also studied: Effect 5 times faster

27. SPATIAL UNIFORMITY  2 m UNCORRECTED Beam deflection  2 rad Transmittance above 80 %

29. 2 = w1 T2 + w2 R2 + w3 2n + w42k + w52n +w6 2k + w7 (6-n)2 + w8(1-n) + w9(1-k2) + w10 k 2 Measured data Monotonous (n,k) ni  ni-1 , ki  ki-1 Reasonable index limits Twofold Simulation Aim: i) Provide an explanation for the observed sensor systematics ii) Being able to define repeatable configurations ensuring maximum %T for balanced sensor response. Hypothesis: Interferences rule sensor operation  Calculation of %T %R curves E1 = M1 M2 M3 … Mq Eb MM(Ni,di) N = n - i k Non-infinite substrate must be included in simulation  (N,d) difficult to be measured. %T and %R are easily measured We have developed a calculation method which provides knowledge of (N,d) of a multilayer, once %T and/or %R are measured.  (N,d) calculated via 2 minimizations:

30. pin a-Si:H layer (JENOPTIK) Data: Na-Si:H measured   690,900  nm %T vs  Two thickness measurements (@centre,@extreme) Origin of differences is the deposition process

31. No oscillations  Thin layer 2 method applied to the 4 tabulated values dITO (n,k) calculated from T dITO recalculated Data: No NITO was measured Only NITO @ 650, 700, 750, 800 nm %T vs  Iteration dITO = 47.2 nm

32. Na-Si:H for pin layer on glass  N values fitted to continuous functions (NITO , dITO) thin layer on glass  di left free Starting values  (100,1000,100) %T and %R Sensor Understood

33. T  35 % due to are possible Maximum %T compatible with balanced signal requested Designs tolerance must be calculated d0= (103,1056,73) nm dopt= (109,1113,106) nm Optimal configuration Tolerance: Tthreshold > 79% (1,2,3) = ( 12,12,12) nm

35. Most critical CMS coordinate  will be measured using TILMETERS (TmT) Tiltmeters, clinometers, tiltsensor are equivalent terms Measure angle (w.r.t gravity) of the elements to which they are attached Simulation: TK-MS  20 rad   15 rad Studied TmT from A.G.I. and A.O.SI. AGI SCU (ACDC), up to 50 m cable in between, AOSI, “integrated SCU”

36.  TmT come calibrated from manufacturer. Prior to utilisation we re-calibrated them. We WANT LINEAR and PRECALIBRATED sensors.  Calibration: Find relationship between angle moved in plane XZ and output voltage  TmT: 1D sensors, 3D objects

37. v represents the TmT ( Z , v )  Angle TmT vs gravity. Calculating the complementary    represents a wedge   is the misalignment     Angle tilted by tripod TmT employed to calculate this angl.e    True angle tilted by TmT       arc sin ( cos   sin   sin  + sin   cos  )

38.  We always consider the misalignment in the fits. V = V0 + k+ k ’ 2 Is the calculated  reliable ?  = (84.70.6) deg  Approximating  in - deg: V = V0+k sin   + k’ sin2  2 Not possible to calculate k and  in single fit (k,) from fit will always be correlated  Proper calibration of the sensor demands misalignment to be known AGI controls calibration to 1 deg  k AGI can be trusted

39. AGI sensors suitable for our needs  In a linear calibration  is fixed. We can therefore calculate ratios of magnitudes involving . AOSI sensors are discarded  = moved - calc AGI 1 resolution  3.3 rad AGI 2 resolution  6.4 rad AOSI´s resolution  30 rad (order 6 polynomials)

40. Calibrated  Extra equation needed! V = V0 + k () + k ’ 2 ()  Use 2 sensors under same  Unknown Recipe  Calibrate each sensor independently  Put them under ANY angle   Calibrate the “dual” device, and calculate 1c - 2c  Start measuring Current misalignment V1 = V01 + k1+ k1 ’ 2 V2 = V02 + k2+ k2 ’ 2 From calibration From equations

41.  Former method applied to 2 AGI sensors  1 calculated and utilised to compute moved  Showing platform- moved Provided misalignment  < 4 deg,  -  < 15 rad

42.  TmT give local measurements  Measurement of large structures possible combining 2 simultaneous tilt-measuring systems  After 48 hours (4848)=(-723.01.2,-12.3  4.7) rad Laser Level (LL) is the junction of TmT and ALMY+laser systems   TmT reading when TmT  g   Angle of laser beam w.r.t. Horizontal when TmT angle is   Values ()=(-750.71.4,-39.3  0.6) rad measured We detected a combined tilt since: -27 rad most probably due to mechanics

44. per year at high Luminosity  109 interactions/second  c-Si detectors requested to be operational for 10 years. Same or higher endurance would be desirable for alignment components  Inner TK: Charged hadron Flux  1/r2, E < 10 GeV  Outer TK: bigger n-fluence in last endcap disks  ECAL: n albedo produced in ECAL  HCAL: =3, 10 kGy/year, n-fluence 1014 cm-2  DTs: Machine bckgd. most important at low L 10 years Highlights:

45. Schottky + electronics -rays and neutron irradiation of 2 ALMY sensors Bare pin sheet  En = 3.7 MeV HeNe (633 nm), 2 ALMYs (D = 2.58 m) 1616 (1 mm pitch scan) Sensors not powered during tests Measuring optical properties after each iteration. Also response to white light recorded for Schottky  irradiation: Steps of 100 Gy, 10, 15, 20 kGy Velocidad de gamma? n irradiation  Fast n source based on the MGC-20 cyclotron @ ATOMKI (Debrecen, Hungary)  Fluence: 1.11015n/cm2  10 years flux = 1.6109 cm-2 s-1  Steps 1.1  1014,1015 Scans utilised Halogen lamp + diffuser

46.  irradiation 1014,1015 n/cm2 DEFX %T DEFY

47. After 200 Gy MUX SILICONIX DG406 (16:1) malfunctioned. Resistors and capacitors survived Sensors illuminated using uniform white light, irradiance 0.16 mW/cm2 After 10 kGy photons 10% degradation 1014 n/cm2 20% further degradation 1015 n/cm2 15% further degradation Response degradation %T yet comparable to other samples

48. Link optics  Transparent rhomboid prisms and right angle glued together  Attached to TK, splitter and mirror glued to fused silica bar Irradiated; BK7-G18 optical grade fused silica (synthetic quartz) BK7: turned black Fused silica: turned gray Stable T,R < 0.5 % for synthetic quartz   rays (1.17 MeV, 1.33 MeV) 60Co 3 kGy/hour @ NAYADE (CIEMAT)

49. Triple ARC on BK7-G18 Dose: 100 kGy (10 years CMS) Negligible effect Ag coating on back face Al coating on front face  RC and ARC increase %R and %T of materials, respectively  Coating performance should remain independently of radiation dose

50. We have introduced the LHC machine and the CMS experiment as the collider machine and particle physics experiment of a new generation  To fulfil physic goals, stringent performance in lepton measurements are needed. For muons, this demands a knowledge of the detector positions comparable to detectors intrinsic resolution. This can be achieved by the hardware alignment system described.  Alignment tools are: laser beams, position detectors (that give true spatial information of the beam coordinates), tiltmeters (to measure orientation), distance-meters and temperature probes. All components should cope with radiation environment and space constraints.  ALMYs are an innovative solution for alignment strategies. They are transparent allowing a multipoint alignment easy to implement.  Our tests of ALMY sensors have shown that their spatial resolution is better than5 m, which matches alignment requirements.