BeamCal (note that dimensions in the above picture might have changed):

BeamCal is an electromagnetic sandwich calorimeter that uses Tungsten as absorber. It serves three major purposes:

1. Improving the hermeticity of the ILC detector  by providing electron and photon identification down to polar angles of a few mrad. This is a specially challenging task due to the vast amount of deposited energy from the electron-positron pairs originating from beamstrahlung.

2. Reducing the backscattering from pairs into the inner ILC detector part and protecting the final magnet of the beam delivery system.

3. Assisting beam diagnostics. A fast luminosity signal will be provided by BeamCal. The detailed analysis of the shape of the energy deposition from pairs hitting the BeamCal grants access to parameters of the colliding beams.

The sensors of the BeamCal must be very radiation hard. The technologies under investigation are:

• polycrystalline CVD diamond (Chemical Vapor Deposition),

• single crystal CVD diamond,

• GaAs,

• radiation hard silicon.

Geometries (LDC V5):

 

Table 1: BeamCal geometries for different beam settings.
^* We assume an Anti-Detector Integrated Dipole field: the magnetic field is parallel to the outgoing beams. Optimized for low backgrounds.
^**Crossing angles of 14 or 20mrad require an additional hole in each BeamCal for the incoming beams.

		Unit	14 mrad
Graphite shield thickness		mm	100
Absorber layer	1 X0	mm	3.5
Sensor layer		mm	0.3
Readout plane/air ap		mm	0.2
total X0		int	30
x/y/z position		mm	+24.2/0/±3450
Rinner (sensitive area)		mm	20
Router* (sensitive area)		mm	150
Rbeam_in**		mm	15
θinner		mrad	5.8
θouter		mrad	43.5
Tilt		mrad	7
~ Weight of absorber and sensor (sensitive area)		kg	144.4

Table 2: BeamCal segmentation.

		Unit	14 mrad
0.8 RM cell size	Rings	int	16
	ΔR	mm	8.125
	Sectors	int	8 of 45 degree
	Cells per sector	int	160
	Cells/layer	int	1280
	Blind area	degree	±22.5 around incoming beam, rings with R>63.4 are complete (n > 6)

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LumiCal:

LumiCal serves three major purposes:
 

1. Improving the hermeticity of the ILC detector  by providing electron and photon identification down to polar angles of a few mrad.

2. Reducing background by acting as a mask.

3. Measuring the rate of Bhabha events at low angles. The well known Bhabha scattering cross section will allow the precise determination of the luminosity of the ILC. Achieving the desired precision of 10^-4 is a challenge.
    

The technology of a Si-W sandwich calorimeter is under investigation for the LumiCal.

One of the challenges for LumiCal is the needed mechanical precision. A laser based position monitoring system is under development for LumiCal.

Geometries:

GamCal:

GamCal is a calorimeter designed to measure the beamstrahlung photons, which are very collinear to the beam. Therefore GamCal has to  be positioned some 100 meters down the beam lines in the extraction line. More details to be added soon.

Pair Monitor:(New!)

Pair-monitor is the Silicon pixel sensor designed to measure the beam profile at the IP:

• Beam size

• Displacement and rotation of the beam

• The number of particles in the beam bunch

Pair-monitor is designed to be located at the first layer of BeamCal.

Geometry:

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