LumiCal High density compact calorimeter at the ILC Wojciech Wierba Institute of Nuclear Physics PAS Cracow, Poland

SLAC January 6-8, 2005Machine-Detector Inerface at the ILC2 Bhabha process e + e - => e + e - (γ) Accuracy of the luminosity measurement = ~10 -4 Covers polar angles θ between 26 and 82 mrad.

SLAC January 6-8, 2005Machine-Detector Inerface at the ILC3 The New Layout of the Forward Region Final focus system L* = 4.15 m Compact design of the LumiCal More space for electronics and cabling

SLAC January 6-8, 2005Machine-Detector Inerface at the ILC4 Segmented silicon sensors interspersed into the tungsten half disks Two half barrels to allow for mounting on closed beam pipe The blue bolts support the heavy part of the detector, tungsten half disks The red bolts carry only the sensors Holes for precision survey the sensors position Mechanical design

SLAC January 6-8, 2005Machine-Detector Inerface at the ILC5 Silicon sensors Pads design ‘Shower peak design’ First 4 rings will consist of 24 radial sectors and 10 cylinders Next 15 rings will consist of 24 radial sectors and 22 cylinders Last 11 rings will be segmented as the first 4 rings

SLAC January 6-8, 2005Machine-Detector Inerface at the ILC6 The layout of a silicon sensor of the pad version The rough segmentation The fine segmentation

SLAC January 6-8, 2005Machine-Detector Inerface at the ILC7 Silicon sensors Strips design The odd rings contains 64 concentric strips The even layers have 120 radial strips

SLAC January 6-8, 2005Machine-Detector Inerface at the ILC8 The layout of a silicon sensor of the strip version The odd half layerThe even half layer

SLAC January 6-8, 2005Machine-Detector Inerface at the ILC9 Pads or strips ? PadsStrips Set of masks24 Number of channels Energy resolution  26 %  E  %  E Angular resolution  ~  rad  ~ 50 – 90  rad Capacitance ratio on tile Mean area of pad/strip630 mm mm 2 Smallest pad/strip302 mm mm 2 Largest pad/strip955 mm mm 2 Capacitance ratio Bias, coupling to amplifierscomplicatedeasier Number of sensors per tile20 rough, 44 fine10 radial, 64 conc.

SLAC January 6-8, 2005Machine-Detector Inerface at the ILC10 Precision assembly and positioning of the LumiCals To achiev ΔL/L = ~10 -4 : Inner radius of LumiCal~0.7 μm Distance between LumiCals~60 μm Transversal (x, y) position~100 μm

SLAC January 6-8, 2005Machine-Detector Inerface at the ILC11 Precision assembly of the LumiCal Optical survey of the sensors marks through the holes On line check of the sensors position (?) Inner radius of detector after closing the half barrels Position of the sensors after kipping the LumiCal to working position Thermal stability (constant temperature?)

SLAC January 6-8, 2005Machine-Detector Inerface at the ILC12 Monitoring of the LumiCal position The beam pipe is proposed as the reference. Precision survey of the beam pipe before instaling The Beam Position Monitors are mounted inside the vacuum pipe => allow to determine LumiCal position with respect to the beam

SLAC January 6-8, 2005Machine-Detector Inerface at the ILC13 Simple laser – CCD camera position measurements Resolution 1  m if the accuracy of determination of the centre of the light spot is better than 0.1pixel

SLAC January 6-8, 2005Machine-Detector Inerface at the ILC14 X, Y, Z displacement measurement BW camera 7.5 μm x 7.5 μm pixel size New precision movable table Semiconductor lasers Will be tested soon

SLAC January 6-8, 2005Machine-Detector Inerface at the ILC15 Conclusions Rotation of the odd and even planes by 7.5° Gaps between tiles Pads edges, guard rings Concentric stripes divided in 6 parts, radial in 2 parts for half plane Readout electronics noise More realistic MC