IFR status and outlook Roberto Calabrese Ferrara University
IFR status and outlook Roberto Calabrese Ferrara University and INFN Super. B Workshop, Perugia June 16 -19, 2009
Outline n n Introduction Progress since Orsay Future activities towards TDR Milestones
The IFR for Super B • The muon detector is build in the magnet flux return. • It will be composed by one hexagonal barrel and 2 endcaps like in Babar. • Possibility to reuse Ba. Bar iron structure • Scintillation bars with WLS fiber to sustain rates O(100 Hz/cm 2)
IFR requirements for Super B • Add iron to Ba. Bar stack to improve m ID: 8 detection layers should be enough • Keep longitudinal segmentation in front of stack to retain KL ID capability. The CDR layer configuration Need to optimize: - Scintillation bars geometry - Number of active layers - Where and how much iron we need to add
The CDR style IFR • This technology was proposed also as replacement of the Ba. Bar barrel. • One coordinate is measured by the position of the scintillation bar. • The other coordinate by measuring the time at both end of the bar. • Need input from simulation and background evaluation. – Time resolution and spatial segmentation – Number and location of active layers. • Need full simulation of the detector, reconstruction code and muon selectors. From CDR: possible 4 fibers readout
Evolution from CDR ? • Some of the questions that we need to answer for TDR ? – Number of fibers per scintillation bar ? – WLS fiber diameter (1 mm), shape decay time, … ? – Use Geiger Mode APDs instead of APDs ? – What is the best mechanical design ? – What electronics ? – Read one or two side of the scintillator
The scintillator bars • In contact with FNAL-NICADD facility • Various candidates: • We have some spares from Minos and Itasca company that we are using for R&D
From Orsay to Perugia and beyond End of Orsay meeting Now • R&D needs • evaluate different readout options studies in progress + simulation needed • evaluate the possibility to bring the photon-detectors out of the iron studies completed (will be reported in this meeting) • impact of neutron background on Si. PM preliminary tests done • Iron Structure: new structure vs partial recycle of Ba. Bar iron (or total recycle) • impact on the budget • impact on the performances first cost evaluation waiting for the simulation
Different readout options: 1 st option: measure both coordinates with one scintillation bar (position + time). This is the baseline for the barrel. As 2 -nd option we are considering the “double coord layout”: orthogonal scintillator bars, 1 cm thick (mechanically rather complicated for the barrel) 1 st option 2 nd option Sketch of the two readout options
Light loss in the CLEAR fiber • WLS and clear fiber are coupled mechanically, no splicing After 10 m of 1. 5 mm clear fiber • We expect roughly a 10% coupling loss • L= 10 m, att length l = 10 m No clear fiber <Q> = 146 ch <Q> = 446 ch • Aexp = Acoupl e-l/L ~ 0. 9 * 0. 37 ~ 0. 33 • Ameas=146/446 = 0. 33 ADC ch • This confirm our estimate for the fibers coupling loss 10
1 vs 2 vs 3 kuraray fibers at the close end (CLOSE end: ~0. 3 m from scintillator) 1 fiber R 2/1 = 1. 46 ADC ch 2 fibers 3 fibers R 3/1 = 1. 65 With 3 fibers we gain only 13% more signal wrt 2 fiber case
From Orsay to Perugia and beyond
Si. PM currents and dark rates
If preliminary results will be confirmed Si. PM can be damaged with a dose of 109 n/cm 2 Need for accelerator background simulations + study on neutron shielding
From Orsay to Perugia and beyond
- Babar IFR thickness: • • - Barrel = 650 mm Doors = 600 mm Flux return Some parts of Babar have been thickness increased with brass and steel plates Current thicknesses (equivalent): • Barrel ~ 795 mm but last instrumented layer see 695 mm • FW doors ~ 835 mm • BW doors = 600 mm - - Babar IFR with brass filling: Barrel maximum thickness ~ 868 mm but last instrumented layer see ~ 768 mm FW doors maximum thickness ~ 1000 mm BW doors maximum thickness ~ 900 mm CDR baseline = 920 mm Which solution? Scenarios: Doors: brass filling + 100 mm steel, refurbish BW doors as FW ones (up to 920 mm) Barrel: • brass filling + modify arches and cradle to allow outer scint. layer ~ 868 mm • Add 100 mm plate outisde + new arches and cradle + 1 layer brass ~ 915 mm • Replace inner wedges + modify cradle and arches = 920 mm
Flux return cost evaluation Current IFR (wedges + doors + cradle + arcs): Mass 790 t Different scenarios • Brass filling, 868 mm, arches and cradle modified 900 t • Brass + steel up to 920 mm doors and barrel 955 t • New inner wedges, no brass 925 t Fully new IFR, max. thickness (950 mm barrel, 1100 mm doors) 1030 t Cost (0. 4 M€ transportation cost) 1. 3 M€ 1. 4 M€ 2. 1 M€ 3. 5 M€
From Orsay to Perugia and beyond
Digitizer + clusterizer
From Orsay to Perugia and beyond
From Orsay to Perugia and beyond
Prototype preparation layout based on: • 5 layers of x-y scintillators, 1 cm thick, read in binary mode • 3 layers of scintillators 2 cm thick, read in timing mode Design of the prototype has started and will be finalized based on R&D and simulation. SCINTILLATORS/ FIBERS FRAME IRON Electronics for the prototype is being designed to test different readout options. Cooling system and other infrastructures to be developed. Need to place the order for the scintillators by September: schedule for simulation is very tight.
From Orsay to Perugia and beyond
Milestones toward the TDR September 09 Fall 2009 January 2010 Spring 2010 order scintillators for prototype construction (needed simulation results) finalize prototype design (mechanics and electronics) and begin construction. begin prototype assembly prototype test with cosmics Summer 2010 test beam Fall 2010 write TDR A lot of work to be done, but it seems we are on the right path
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