Jens Frangenheimphysik rwthaachen de III Physikalisches Institut A

Jens Frangenheim@physik. rwth-aachen. de III. Physikalisches Institut A RWTH Aachen University CMS Upgrade Workshop at FNAL, 2008/11/19 to 2008/11/21 Muon Detector Working Group, Thursday, 2008/11/20 09: 40 Specific interests of German groups Hardware development for a scintillator based MTT General detector development plans Aachen IIIA / IIIB and DESY collaboration Associated work First steps 1

general detector development plans Muon fast Track Tag muon system + absorption by calorimeter and coil - tracks affected by multiple scattering + redundancy given by RPCs idea: Bologna tracker - huge number of tracks + precise pt measurement (high resolution, less material, strong B-field) use a new part of muon system (MTT) to select an interesting region in the tracker in L 1 -trigger also Aachen III, DESY in addition to Bologna calorimeter tracker by A. Montanari one option: use scintillator based MTT muon tag 2

CMS Upgrade document n. 97. 09 / A. Montanari general detector development plans MTT design – German focus based on the MTT idea including dimensions develop scintillator detector (slide 18 from Pierluigi`s talk) German groups focusing on detector development and building (long tradition in 3 Aachen)

general detector development plans MTT hardware – dedicated technology Idea: Scintillator based MTT readout by Silicon. Photo. Multipliers maintenance free no gas needed very fast any requested resolution possible Hamamatsu Si. PM: 100 µm x 100 µm pixels no HV needed (Usupply < 100 V) 2 less power needed (< 0. 2 m. W/mm ) very good timing (100 ps to 1 ns) high photon detection efficiency (up to 65 %) but high noise rate (up to 1 MHz/mm 2 at 0. 5 PE threshold) and small active surface (up to 3 mm x 3 mm at the moment) Best suited device for triggering at the moment: - highest photon detection efficiency - low noise - will soon be produced in CMOS technology (cheap) 4

Aachen IIIA / IIIB and DESY collaboration Aachen IIIA: - simulations about light collection /Si. PM signal timing - combining MTT with muon chamber Aachen IIIB: - experience from tracker development - Si. PM supply electronics development Aachen IIIA + Aachen IIIB: (finally) building the MTT DESY: HCAL group member, possible integration with HO 5

Aachen IIIA / IIIB and DESY collaboration MTT at Aachen IIIA – Scintillator designs Two possible designs: “Traditional” one: “New” one: + light collecting in WLS fiber → more light/photon detector surface - mechanical effort o good time resolution o scintillator plates with embedded Wave. Length. Shifting fibers WLS fiber (green light) Si. PMs directly mounted to scintillator plates (was done with huge PMs) low light yield - but readout perhaps possible (high pde, large Si. PMs (~ price as smaller ones) + simple mechanical construction + very good time resolution - maybe more readout channels, power consumption scintillator (blue light) Aachen photon detectors 6

Aachen IIIA / IIIB and DESY collaboration MTT at Aachen IIIA – Light collection studies diffuse reflection - try to find best position of Si. PMs, wrapping of scintillator, shape of WLS fiber - have developed “standalone“ scintillator + Si. PM simulation “normal” reflection - diploma student is working on GEANT simulation total reflection Aachen IIIA cosmics testing (student project) 7

Aachen IIIA / IIIB and DESY collaboration MTT at Aachen IIIB brings in experience from tracker (petals) assembling / testing: - one focus: development of compact Si. PM readout electronics - especially: development of a gain stabilization on a chip (Si. PM gain is temperature and maybe time and radiation dose dependent) Aachen IIIB Si. PM-cosmics testing 8

Aachen IIIA / IIIB and DESY collaboration MTT at Aachen – common Aachen IIIA/B parts timing (kind of coincidence, time resolution) (trigger) electronics tests build large test detectors tests together with other detectors (muon chamber, petal) ic sm co tracker petal n uo m MTT test detector muon chamber Si. PM mounted on Aachen pcb, first test with scintillator CMS silicon petal quality control at Aachen IIl. B 9

Aachen IIIA / IIIB and DESY collaboration MTT at DESY - DESY member of HCAL group (CASTOR) - interested in combination MTT with HO - change of HPD in Si. PM for HO needed → exchange of initial two readout-boxes planned for this shut down → get experience with the longterm operation with Si. PM (new detector technology, also at T 2 K starting 2009) - further discussion between Muon and HCAL groups underway, need experiences with HO with Si. PMs and for sure simulations everywhere 10

associated work Associated work 11

associated work Implementation of MTT into CMSSW Scintillator very sensitive to background ! scintillator can probably not distinguish between kinds of particles scintillator does not measure momenta MIP produce less light than background (e. g. slow protons, electrons) background rate of all (charged) particles including low momentum particles timing of background (and signal) momentum of background particles (absorbing / producing secondary particles) 12

associated work Strategies to limit sensitivity of MTT to slow e pion background Absorber (thin, between 2 scintillator layers): Absorbs low momentum particles between the two layers. → MTT gets too thick ? Two layers too expensive ? Use multiple scattering/magnetic field deflection → Does not work with one MTT element. - MTT layer 1 absorber (Pb) MTT layer 2 new particles Set time-of-flight gate: neutron induced proton Reduce sensitivity to neutron background, slow pions and kaons → Need high time resolution, more electronics ? Set pulse height amplitude (=amount of light) limit: (background produces mostly more light than MIPs) Combination with HO 13

first steps First steps 14

first steps Simplest scintillator based detector + very simple set up Si. PMs directly coupled to front side of a piece of scintillator 100 mm + thin construction + very good time resolution idea: T. H. for SLHC - a lot of Si. PMs needed - many readout channels (but high resolution) Aachen Si. PMs (3 mm x 3 mm) in unconventional position 15

first steps Simulation results (2) Assuming: - 90 % diffuse reflexion at surrounding 3 M tape - 3 mm x 3 mm detectors - 65 % photon detection efficiency (80 % coupling efficiency) 4 PE threshold 16

first steps Simulation results (2) need 2 of 4 coincidence (4 PET for each Si. PM) noise rate < 1 Hz efficiency > 80 % for 10 mm thick scintillators (gets ~ 100 % for 95 % reflective wrapping) (to be tested with larger scintillators) no correlation with Si. PM position visible position of Si. PM 17

first steps. WLS fiber simulation Simulation for WLS fiber setup (1) Si. PMs (Hamamatsu 100 pixels, 1 mm x 1 mm) piece of scintillator (BC-404) µ WLS fiber (BCF-92) 10 0 ) 10 simulated 10000 muons traverses 100 - uniform distributed, vertical particle transition - require coincidence (interval < 10 ns) between both Si. PMs with 3 PET → noise rate < 1 Hz 18

first steps Simulation for WLS fiber setup (2) light collection effect of WLS fiber huge more than 98 % detection efficiency (using 1 mm x 1 mm Si. PMs) time resolution of detector still good 19

conclusion Conclusion MTT is a promising concept to include tracker data into L 1 muon trigger: - DT and RPC can be kept as independent systems. - MTT can also solve DT occupancy problem (at L 1 -trigger). Scintillator based MTT could be an easy and cheap solution: - It can be inserted in addition to existing detectors. - Si. PMs are a very promising technology. - German groups can contribute to detector development and building. - MTT/HO: under discussion, several aspects to be clarified At SLHC may need any kind of redundancy ! 20