Total Cross Section Elastic Scattering and Diffraction Dissociation

  • Slides: 32
Download presentation
Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC TOTEM Total cross

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC TOTEM Total cross section measurement at LHC Marco Bozzo INFN Genova and Universita’ di Genova (Italy) On behalf of the Collaboration: Brunel, CERN, Cracow, Dresden, Genoa, Grenoble, Helsinki, Prague. http: //totem. web. cern. ch/Totem/ Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 1

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC stot Marco Bozzo

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC stot Marco Bozzo INFN Genoa • Dispersion relation fit (logs)g , g=2. 2 0. 3 • Current models predictions: 100 -130 mb • Aim of TOTEM: ~1% accuracy • Absolute calibration of Luminosity LHC 2003 - FNAL Workshop - May 2, 2003 2

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Luminosity Independent Method

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Luminosity Independent Method (i) “OPTICAL THEOREM” (ii) Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 3

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Large-t Elastic scattering

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Large-t Elastic scattering Impact picture and Regge models Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 4

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Inelastic detectors (T

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Inelastic detectors (T 1 and T 2) in CMS Elastic detectors (RP’s) in the straight section Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 5

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Elastic scattering and

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Elastic scattering and High β optics u u u u Cross section is large can be measured with relatively Low Luminosity ~ 1028 and short runs. Low divergence beams require a special High- β optics. For β=1100 m beam angular spread at IP is 0. 67 μrad and beam size is 0. 74 mm (rms). Crossing angle of 150 μrad is not sufficient to avoid parasitic collisions need zero crossing angle: 36 bunches 1 out of 100 (time separation ~2. 5 μsec or 740 m) to measure precisely the angle of scattered particles very close to the beam detectors placed at π/2 phase advance. This results in a “parallel to point focus” optics where displacement correlates directly to the scattering angle 2 such points exist in warm section n measure possible in Horizontal or Vertical plane. Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 6

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC b* = 1100

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC b* = 1100 m x = Leff q + vx 0 v Leff(m) RP 1 = 147 m RP 3=215 m efficient as close as possible to the beam Acceptance: pots at same position and different inefficient edge of detectors Acceptance: track seen in either pot compared with single pot acceptance Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 7

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Ldt=1033 cm-2 elastic

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Ldt=1033 cm-2 elastic scattering 1 eff. day (105 sec) b* = 1100 m 18 m L = 1028 1032 cm-2 sec-1 1037 cm-2 5 x 103/Ge. V 2 Max t b* = 18 m Max t b* = 1100 m 15/Ge. V 2 ( M. Islam ) Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 8

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Roman Pot Window

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Roman Pot Window thickness 0. 1 mm – First tests in 2002 Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 9

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Roman Pot detector

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Roman Pot detector 50 μ pitch Si strip detector CMS Hybrid ~3 cm Thermal analysis Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 10

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Detectors for elastic

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Detectors for elastic scattering Much effort to operate At the largest beta, closest to the beam (10 σ-beam ~ 0. 5 mm), with reduced n. of bunches and emittance … Delicate part is the design of the detector region near the beam and the choice of the detector: The window, the mechanical tolerances, the inefficient region should be minimum u u u Standard silicon : 0. 5 mm guard ring (typ. ) Silicon strip at LN 2 temperature. Can work with efficiency up to the edge when edge is ‘cut’ (and properly treated). idea suggested by RD 39 and NA 60, tested on beam by TOTEM in 2002. 3 D detectors: edgeless and warm (S. Parker, C. Kenney), test of 1 cm x 1 cm detector with beam in summer 2003. Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 11

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Cold Silicon can

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Cold Silicon can be edgeless - tests 2002 Cut diode gives Pair of edgeless detectors (RD 39 - Z. Li / BNL) Edge of ‘cut’ Silicon Strip Detector (50 m pitch) 3 D Microstrip Marco Bozzo INFN Genoa Diodes CMS Tracker LHC 2003 - FNAL Workshop - May 2, 2003 Microstrip Silicon Sensor (NA 60 - Z. Li / BNL) 12

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Cold Silicon Tests

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Cold Silicon Tests Results Silicon Microstrip Detectors P 3 Edgeless Silicon Diodes (RD 39) Cut strip detector P 7 P 4 100 V bias 500 000 Events P 8 beam 15 mm 1. 2 mm 140 mm P 6 140 mm Edgeless diode pair 6 x 6, 0. 4 mm gap 24 strips x 50 mm (NA 60) with tracks = 471 50 m measured from Survey = 435 35 m Sensitive edge coincides with survey within one strip ~ 0 ± 30 m Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 13

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Edgeless and warm

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Edgeless and warm : Si 3 D Detectors S. Parker, C. Kenney 1995 New ‘ 3 D’ TECHNOLOGY E-field line contained by edge (p) electrode SENSITIVE Within 10 m of EDGE Side view v. EDGE SENSITIVITY v. COLLECTION PATHS <10 mm ~50 mm v. SPATIAL RESOLUTION 10 -15 mm v. DEPLETION VOLTAGE < 10 V v. SPEED AT RT 3. 5 ns v. SENSITIVE AREA 3 X 3 cm 2 v. SIGNAL AMPLITUDE 24 000 e before Irradiation 15 000 e- at 1015 n/cm 2 Marco Bozzo INFN Genoa 50 mm pitch Pictures of processed structures Brunel, Hawaii, Stanford 2003 LHC 2003 - FNAL Workshop - May 2, 2003 Top view 14

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC 3 D response

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC 3 D response to particles Brunel, CERN, Hawaii, Stanford Pulse height v. Small bias 5 -8 V v. Speed 1. 5, 3. 5 ns v. Radiation hardness Ileak = 0. 45 n. A (average) 200 m Ileak = 0. 26 n. A (average) 100 m C = 0. 2 p. F per electrode Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 MIP 1 x 1015 p/cm 2 20 o. C 15

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Miniaturization of Roman

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Miniaturization of Roman pots u To approach beams in the horizontal direction, where space between the pipes is small, the detector movement might become smaller if put in “secondary” vacuum together with detectors. We are studying how to approcah beam “horizontally”. P beam Detector Secondary vacuum Beam vacuum Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 16

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Roman Pot Trigger

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Roman Pot Trigger u Silicon detector pad for trigger: 500 pads of 1 mm 2 Si-pad geometry (Sintef) u Trigger chip under study n n n Fast-or of 128 channels for fast trigger extraction Multiplicity processor to reject multi-hit events Timing precision about 1 nsec useful to identify by TOF the longitudinal position of interaction Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 17

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Elastic detectors u

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Elastic detectors u u 100 -150 small size (~4 x 4 cm) silicon detectors necessary for entire experiment No extreme requirements on radiation hardness. Read out with CMS APV hybrid allows also easy integration in CMS DAQ for common runs. Choice on final technology will be taken during 2004. Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 18

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC The measurement of

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC The measurement of the inelastic rate n n n Needs fully inclusive “minimum bias” trigger with known efficiency Identification of beam-beam events from background by reconstruction of interaction vertex Two main event topologies NSD ~85% of inelastic cross section l SD ~ 15% l n Trigger combinations Double arm for NSD (clean, low background) l Single arm for SD (beam gas int. looks like SD!) l requiring signal in roman pot on opposite side can help in removing background n Marco Bozzo INFN Genoa Simple detector telescopes in the forward region LHC 2003 - FNAL Workshop - May 2, 2003 19

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC ~ 30% of

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC ~ 30% of σ tot EVENT TOPOLOGIES Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 20

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC TOTEM inelastic rate

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC TOTEM inelastic rate measurement Measurement of the inelastic rate with an overall error of the order of 2% detector spans ~ 4 units of pseudorapidity (on both sides) The value at coordinates min, max is the % event loss of the TOTEM inelastic telescopes ~ 85% of events 1 -2 % loss ~ 15% of events 10 -15 % loss 3 -4 % global loss Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 21

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC T 1 TELESCOPE

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC T 1 TELESCOPE (η~3. 1 to 4. 7 on each side) u u Trigger by RPC n Two double gap chambers n Pads with projective geometry n Time resolution ~1 ns Vertex reconstruction by CSC n 5 planes with 3 coordinates point l 2 cathode planes + anode wire plane -CANTILEVERED STRUCTURE FIXED ONLY ON OUTERMOST CMS YOKE RING -TWO PLATES (Light blue) ARE THE ONLY INTERFACE BETWEEN CMS AND TOTEM T 1 -RAILS INSIDE PROFILE TO OBTAIN MAXIMUM ACCEPTANCE Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 22

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC T 1 telescope

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC T 1 telescope ALUMINIUM FRAME/SUPPOR T CSC PLANE SUBASSEMBLY Marco Bozzo INFN Genoa HALF DETECTOR SUB-ASSEMBLY DETECTOR IN TWO HALVES, TO ALLOW INSTALLATION WHEN THE VACUUM CHAMBER IS ALREADY IN PLACE ALUMINIUM FRAME HOLDS EACH CSCs, RPCs PLANE AND PROVIDES SUPPORT AND COOLING FOR ELECTRONICS, SERVICES AND LINK TO THE RAILS DETECTORS OVERLAP, PLANES ARE ROTATED IN φ WITH RESPECT TO EACH OTHER. LHC 2003 - FNAL Workshop - May 2, 2003 23

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC T 1 Telescope

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC T 1 Telescope n n n T 1 is installed in the CMS end cap η~3. 1 to 4. 7 on both sides Detector on platform (cables and service racks) tested before installation. Cables and services arrive via HF cable ducts Installation time of the order of 1 -2 days. Last operation in CMS closing schedule Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 T 1 installation platform 24

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC u In 2002

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC u In 2002 we have also built and tested full scale prototypes of CSC and RPC. CSC: n n n u Built using similar technology as CMS (invaluable advice and help from CMS FNAL Muon group) 1. 0 m x 0. 8 m prototype. R/O with AD 16 from CMS (anodes) and Gassiplex from ALICE for cathode strips. Plan to use adapted CMS CSC R/O chain RPC: n n n ~1. 0 m x 1. 0 m quadrant and 30 cm x 30 cm 3 m apart Square pads 4 x 4 cm. Test original pad structure and measure resolution time for trigger Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 25

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC CSC prototype tests

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC CSC prototype tests 2002 Spatial resolution rms=0. 6 mm Residuals (mm) Threshold 0. 1 V 0. 3 V 0. 5 V 0. 7 V Anode plane efficiency (CMS electronics various thresholds) Cathode plane efficiency (R/O with the ALICE Gassiplex electronics) high voltage Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 high voltage 26

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC RPC prototype tests

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC RPC prototype tests 2002 Time resolution: 0. 66 ns Rate capability up to at least 1 k. Hz/cm 2 Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 27

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC T 2 telescope

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC T 2 telescope HF (CMS) 13570 400 Geometrical Considerations Distance from IP: Vacuum chamber inner radius: 13570 mm 25 mm Wall thickness, clearances and tolerances: Length: Marco Bozzo INFN Genoa T 2 inner radius: Outer radius: 25 mm + 8 mm = 33 mm 135 mm 8 mm 400 mm h range : LHC 2003 - FNAL Workshop - May 2, 2003 5. 32 < h < 6. 71 28

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC T 2 telescope

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC T 2 telescope Space for services Lightweight Structure 470 mm Thermal Insulation Bellow Weight estimate: ~30 Kg 400 mm Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 29

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC T 2 telescope

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC T 2 telescope Cooling pipe one plane: 10 double sided detectors mounted on a lightweight disk. Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 30

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Luminosity u u

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Luminosity u u u High β runs provide stot and Luminosity ‘study’ various trigger combinations from T 1 and T 2 The T 1 (Left+Right) will have low background and high efficiency, sees a large fraction of the cross section. define an “effective” monitor cross section and obtain absolute calibration of rate: Calibrate CMS monitors (tracker, HF, …) in common run Luminosity will then be monitored as: Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 31

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Conclusion u u

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Conclusion u u u TOTEM will measure total and elastic cross section in dedicated runs in the initial phase of the LHC. It will provide absolute luminosity measurement and calibration to CMS monitors. The experiment will be ready to run at machine startup. Marco Bozzo INFN Genoa LHC 2003 - FNAL Workshop - May 2, 2003 32