Status of muon monitor R&D and construction Specification Detector support structure Ionisation chambers Acquisition system

Functional specification Goal, monitoring of: muon intensity muon beam profile shape muon beam profile centorioid Dynamic range: 105 Muon intensity: 7.7x107 per cm2 and 10.5 ms Pulse duration: two pulses of: length 10.5 ms separated by 50 ms Accuracies: absolute 10 % relative 3 % reproducibility: - cycle to cycle 1 % - one year 5 % x 10 5 -2 -1 1 2 1.0 2.0 3.0 4.0 r (m) 2nd muon pit

Ionisation Chamber Calibration and Support Structure Fixed chamber mounted on cross shaped structure (AL) Movable chamber behind fixed monitors for relative calibration Design finished Start of Production 06/2004 Movement by stepping motors (no resolvers) Motor driver standard SPS (MIDI) installed in UA 87 (distance 500 m) (available) Interface to network via ionisation chamber acquisition system (RS232) Cables ordered Front end software driver available Stainless and AL Beam Steel

Visual Inspection of Structure Camera 5 m upstream Radiation hard camera (tubes) (available) Standard SPS TV system installation located in UA 87 (distance 500 m ) (available) TV frame transmission via Ethernet Cables ordered Front end software driver available Observation Camera

Ionisation chamber LHC design Parallel electrodes separated by 0.5 cm Stainless steel cylinder Al electrodes Low path filter at the HV input N2 gas filling at 100 mbar over pressure Start of production in 2004 diameter = 8.9 cm, length 60 cm, 1.5 litre

Ionisation Chamber Test in Proton Beam BOOSTER Chamber beam response Chamber current vs beam current slength proton= 50 ns Intensity discrepancy by a factor two FWHMe-= 150 ns Measurements with SPS extracted beam foreseen for 2004 (absolute calibration) Intensity density: - Booster 6 109 prot./cm2 - first pit 8 107 muon/cm2

Principle Schematic of Current Integrator SPS design (about 10 years in operation) Low bias current input amplifier (< 100 fA) Reset with switch across feedback capacitor Gain switched: C1 and C2 (1, 200) Amplifier (1, 4, … 128) Digitalisation by 12 bit ADC

Acquisition Electronics 1 VME crate for acquisition Crate CPU: PowerPC Timing by TG8 module Integrators on 8 channel card 5 cards for whole set up Hardware set up and software driver are available

Ionisation Chamber and Electronics Tests SPS (I) SPS system: Ionisation chambers with parallel electronic geometry (0.5 cm separation) Electronics in surface buildings with a analog signal transmission of about 1.5 km Operation time: chambers over 20 years electronics 10 years Total received dose: ring 0.1 to 1 kGy/year extr 0.1 to 10 MGy/year muon Test method: Chamber gas ionised with Cs source Observation of created charges with installed electronics (about 180 chambers)

Ionisation Chamber and Electronics Tests SPS (II) SPS Results: Relative variation between: successive acquisitions (cycle to cycle reproducibility 0.01) Ds/s < 0.005 between different monitors (relative accuracy 0.03, year to year reproducibility 0.05) Ds/s < 0.01 (for ring BLMs) Ds/s < 0.05 (for Extr., inj. BLMs) Total dose in muon pit 1: peak 45 kGy/year

Summary Support structure could be ready for installation in 2004 Motorisation available and ready for installation Observation camera setups available and ready for installation Ionisation chambers start of production in 2004 installation in 2005 Ionisation chamber time response match specification Ionisation chamber linearity to be tested at muon intensity density in 2004 Data acquisition system available and ready for installation SPS ionisation chamber tests show high relative accuracy and long term stability of system