Total Cross Section Elastic Scattering and Diffraction Dissociation

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC University of Siena Pisa I. N. F. N. Department of Physics TOTEM -T 2 TRIPLE GEM DESCRIPTION OF SIENA ACTIVITY E. Oliveri Totem Collaboration Meeting 8 June 2006 1

tline • PART I TRIPLE GEM CHAMBER Assembly • PART II Siena TRIPLE GEM Testing Laboratory • PART III TRIPLE GEM Simulation • PART IV Time Schedule Totem Collaboration Meeting 8 June 2006 2

Outline Part I TRIPLE GEM CHAMBER Assembly • CERN • – Partners • G&A Engineering • – Assembly and Test at G&A Engineering • Components Assembly & preliminary test Siena Physics Department – I. N. F. N. Pisa • • • Protocol and equipment for the assembly of the chamber Test of the chamber Simulation & data analysis – Problems and upgrading of assembly process Totem Collaboration Meeting 8 June 2006 3

Assembly and preliminary test at G&A Engineering Pressure Test: Dp<1 mbar @ 11. 5 mbar OVP in 15’ Leakage Current Test: I<100 p. A for 5’ @ 500 V for every foil Totem Collaboration Meeting 8 June 2006 4

Problems and upgrading of assembly process Problems • Gas line interrupted between the chamber and the gas fitting. • Glue on electrodes foil Upgrading • A more accurate inspection of incoming components. • Automatic deposition with undervacum degassed glue (already used). • Cut foils borders before the final assembly. • Stretch the DRIFT foil (using the plexiglass chassis) before sticking it on the spacer. Totem Collaboration Meeting 8 June 2006 5

Outline Part II Siena TRIPLE GEM Testing Laboratory • Gas Supply System • TRIPLE GEM Support & Services • Power & Acquisition Systems Totem Collaboration Meeting 8 June 2006 6

Gas Supply System Requirements The • PRESSURE CONTROL: Pressure on the chamber in the range of mbar, avoiding overpressure bigger than 10 mbar • FLOW CONTROL: Control of fluxes of nearly 2 -6 l/h of Ar-CO 2 (70 -30) Totem Collaboration Meeting 8 June 2006 7

Gas Supply System The Project Special Thanks to A. Morelli, I. N. F. N Genova, for suggestions & components. First Stage Pressure Reduction P 3=0. 5 -8 bar Air. Liquide HBS 240 8 3 (Double Stage) G 1 V 1 Secon Stage Pressure Reduction P 5=5 -50 mbar TESCOM-EUROPE Regulus 1 - 5 -50 mbar (Single Stage) G 2 V 3 Flow Control ROTAMETER VOEGTLIN V 300 (3 l/h-5 l/h-16 l/h) + Q-Flow valve NS 2 TP 1 TP 3 G 3 P 1=100 bar V 6 RM BB 1 V 4 V 8 V 5 V 7 V 9 V 10 BB 2 TP 4 TP 2 F 1 NUPRO filter SS-2 TF-LE 0. 5 mm Totem Collaboration Meeting 8 June 2006 8

The Gas Supply System Term of delivery for the pressure reducer postponed to half june for manifacturing problems Variable Area Flowmeter mbar Differential Pressure Gauge Totem Collaboration Meeting 8 June 2006 9

TRIPLE GEM Support & Services Strips & Pads Connections Strips and Pads GND Connection Read. Out Gas Supply HV Supply Totem Collaboration Meeting 8 June 2006 10

TRIPLE GEM Support & Services Mechanical Workshop The mechanical workshop: C. Stanghini & L. Stiaccini. Totem Collaboration Meeting 8 June 2006 11

Power & Acquisition System High Voltage Power Supply Strips & Pads Signal Measurement 4 CH Digital Oscilloscope TDS 3034 B 4 CH Le. Croy 1 GHz Oscilloscope Tektronix 300 MHz 2. 5 GS/s 4 CH High Voltage Power Supply CAEN N 472 Leakage Current Measurement High Voltage Power Supply Monitoring ADC - 2249 W Le. Croy 12 Channels Strips Read Out Board 16 Groups, each of 8 strips Pads Read Out Board 15 Groups, each of 8 pads Keithley 6485 Picoammeter Keithley 2700 Multimeter + Scanner Totem Collaboration Meeting 8 June 2006 12

Power & Acquisition System Electronical Workshop The electronical workshop: R. Cecchi Developmement of readout board for single strip & single pad signal acquisition Totem Collaboration Meeting 8 June 2006 13

Power & Acquisition System Dual Timer CAEN Multiscaler 8 Ch. 100 MHz 8 Ch. Low THR Discriminator CAEN Cosmic-Ray acquisition system Coincidence Unit Le. Croy ADC Modules Delay lines ~2 cm x 2 cm Totem Collaboration Meeting 8 June 2006 14

Outline Part III TRIPLE GEM Simulation • Software Tools • Maxwell 2 d. SV • The Garfield approach • Signal analysis: » time, space & intensity » strip & pad signals Totem Collaboration Meeting 8 June 2006 15

TRIPLE GEM Simulation Software tools Special Thanks to D. Pinci, LHCb Roma-Cagliari Group, for precious initial input. Garfield: Main framework. Maxwell 2 DSV: Electric field map. Magboltz: Electron/ion drift velocity and diffusion coefficients. Imonte: Townsend attachment coefficients for given gas mix. Heed: Energy loss by ionization in gas; cluster production. Totem Collaboration Meeting 8 June 2006 16

TRIPLE GEM Simulation The hole field Map The Field Maps - Maxwell 2 DSV 3 D Analysis from Maxwell 2 DSV obtained by symmetry operation The weigthing Field (Ramo Th. ) Others Electrodes & Conductors @ GND Readout Electrode @ 1 V 3 D Analysis from Maxwell 2 DSV obtained by symmetry operation 2 D Software limitation: We can’t simulate more than one hole 3 D Software upgrape: 2 D Software limitation: The elementary cell allow simulations that involve near holes In pad signal analysis we can’t have a simulation close to four pads corner 3 D Software upgrape: We can describe all elctrodes configuration Totem Collaboration Meeting 8 June 2006 17

TRIPLE GEM Simulation The Drift Zone The Garfield approach The Transfer Zone -Ionization process -Diffusion and drift toward the Gem t & st transfer y n t & st drift DRIFT sxz drift GEM foil TRANSFER Diffusion and drift between the Gem planes sxz transfer TRANSFER GEM foil The GEM foil INDUCTION Avalanche in the Gem planes The Induction Zone t & st induction -Diffusion and drift toward the electrodes -Signal induction Gain Totem Collaboration Meeting 8 June 2006 sxz induction I(t) 18

TRIPLE GEM Simulation Drift Zone heed m 10 Gev in Ar-CO 2 (70 -30) @ stp 0. 3 cm Mean ~ 27 Most Probable Value ~ 13 RMS ~ 30 94 x 0. 3 ~ 28 Totem Collaboration Meeting 8 June 2006 19

TRIPLE GEM Simulation The Transfer Zone DRIFT VELOCITY 5 k. V/cm in 2 mm ~8 cm/ms @5 k. V/cm magboltz mean ~ 26 ns t = d/v = (0. 2 / 8) ms= = 2. 5 e-2 ms = 25 ns Ar-CO 2 (70 -30) DIFFUSION COEFFICIENTS 5 k. V/cm in 2 mm magboltz ~260 um for 1 cm @5 k. V/cm rms~115 mm Ar-CO 2 (70 -30) Totem Collaboration Meeting 8 June 2006 20

TRIPLE GEM Simulation The multiplication process Mean G ~ 15 No outgoing e- ~30% Townsend Coeff. Totem Collaboration Meeting 8 June 2006 21

TRIPLE GEM Simulation EFFECTS OF ELECTRODES CONFIGURATION ON DIRECT & CROSS CURRENTS Signal Collection The weigthing Field Signal on PAD Direct Electrodes Configuration: ONLY PADS ~ 370 n. A Cross 0 n. A Electrodes Configuration: PADS & STRIPS Ramo Theorem Ik(t) = -q v(x, t) x Ekw(x) Direct ~ 150 n. A Cross Totem Collaboration Meeting 8 June 2006 22 ~ 70 n. A

TRIPLE GEM Simulation Starting Point for signal collection Lateral position and arrival time for 1 k euniformly distributed in drift zone From 1 k e- uniformly distributed in drift zone, diffusing for 7 mm in a field of 3 k. V/cm in Ar/CO 2 (70/30) @ STP X end DRIFT GEM 1 GEM 2 GEM 3 READOUT t end Neglecting GEM planes holes effects -Readout current results normalized to 1 k primary electrons -Expected current obtained multiplying by <Ne> in drift zone (27) and by total gain (G 3 -GEM ~ 3. 4 x 103) Totem Collaboration Meeting 8 June 2006 23

TRIPLE GEM Simulation Signal Time analysis DRIFT h e- td h e- GEM 1 CROSS SIGNAL td t GEM 2 Signal of electrons not collected by the readout electrode GEM 3 ti READOUT DRIFT VELOCITY DIRECT Readout Pad SIGNAL Signal of electrons collected by the readout electrode ~7000 cm/usec @3 k. V/cm td t Ar-CO 2 (70 -30) ti td Totem Collaboration Meeting 8 June 2006 24

TRIPLE GEM Simulation Signal Space analysis Neglecting GEM planes holes effects DRIFT sx~300 mm 10 mm GEM 1 GEM 2 Upgrading to consider the effects of GEM planes holes GEM 3 READOUT Readout Pad DIFFUSION COEFFICIENTS ~260 um for 1 cm @3 k. V/cm DRIFT Trasversal GEM 1 Longitudinal GEM 2 x 1 GEM 3 x 6 Readout Pad x 6 Ar-CO 2 (70 -30) x 6 x 12 Totem Collaboration Meeting 8 June 2006 x 6 x 12 x 6 25

TRIPLE GEM Simulation Signal Intensity & Shape MULTIPLICATION FACTORS Number of el. produced per incident particle ELECTRONS COLLECTION Number of el. collected by electrode as direct induced current (e- captured by the readout electrode) or cross induced currents (ecaptured by the others electrodes) Gas & Drift Zone Length Read. Out Geometry & Spatial distribution of the electrons cloud Mean ~ 27 Most Probable Value ~ 13 RMS ~ 30 DRIFT < Ne > G 1 GEM 1 G 2 G 3 GEM 2 GEM 3 READOUT Weigthing field lines Readout Pad Mean G ~ 15 Triple. Gem Voltage, Gas & GEM foil geometry Read. Out Geometry Totem Collaboration Meeting 8 June 2006 26

TRIPLE GEM Simulation Strips Signals Totem Collaboration Meeting 8 June 2006 27

TRIPLE GEM Simulation Pads Signals Totem Collaboration Meeting 8 June 2006 28

Outline Part IV Time Schedule Totem Collaboration Meeting 8 June 2006 29

Time Schedule December January February March Siena’s Lab Simulation Software May The lab is available 16 Simulation Software 30 Work on simulation (from 100% to 0% of working time) 17 28 HV and 2 simple readout Board in Siena The G&A Triple GEM in Siena Planning and manufacturing of the test board Cosmic Ray Signal Apparatus test (coincidence and scintillators’ signal on oscilloscope) Pinci’s Meeting TRIPLE GEM CHAMBER Gas Supply System April Ar-CO 2 Cylinder in Siena First Stage Pressure Reducer in Siena First Contact With Morelli Totem Collaboration Meeting 8 June 2006 Gas System Assembly & test Second Stage Pressure Reducer Order 17 23 24 26 4 15 Morelli in Siena Gas System Planning & Companies Contacts Term of delivery for the pressure reducer Manifacturing problems New term of delivery half june 30