TORCH – a Cherenkov based Time-of-Flight Detector 21 November 2018 TORCH – a Cherenkov based Time-of-Flight Detector Euan N. Cowie on behalf of the TORCH collaboration

Time Of internally Reflected Cherenkov 21 November 2018 Time Of internally Reflected Cherenkov The basics of the TORCH design TORCH - E N Cowie

TORCH in LHCb p 10 – 300 mrad 21 November 2018 TORCH - E N Cowie LHCb showing potential locations for TORCH TORCH - E N Cowie

Motivation 21 November 2018 TORCH - E N Cowie PID Performance of TORCH alongside RICH detectors TORCH - E N Cowie

Motivation σ~10-15ps per track 21 November 2018 TORCH - E N Cowie ToF difference as a function of particle momentum TORCH - E N Cowie

Modular Design 21 November 2018 TORCH - E N Cowie A modular design for TORCH TORCH - E N Cowie

Dispersion 𝑐𝑜𝑠 𝜃 𝑐 = 1 𝛽 𝑛 𝑛 = 1 𝛽 cos 𝜃 𝑐 𝑛 𝑔𝑟𝑜𝑢𝑝 =𝑛− 𝜆 0 𝑑𝑛 𝑑𝜆 21 November 2018 Dispersion n 𝑐𝑜𝑠 𝜃 𝑐 = 1 𝛽 𝑛 𝑛 = 1 𝛽 cos 𝜃 𝑐 𝑛 𝑔𝑟𝑜𝑢𝑝 =𝑛− 𝜆 0 𝑑𝑛 𝑑𝜆 Wavelength (nm) Wavelength dependence of refractive indexes Photon production spectrum TORCH - E N Cowie

Focussing 128 Pixels ~1 mrad 21 November 2018 TORCH - E N Cowie Schematic of focussing optics TORCH - E N Cowie

Focussing Quality qz vs. r θ= 0.7528 + 0.00749 r – 2.22×10-6 r2 21 November 2018 Focussing Quality qz vs. r θ= 0.7528 + 0.00749 r – 2.22×10-6 r2 TORCH - E N Cowie

Photon Detection 21 November 2018 TORCH - E N Cowie Example of MCP internal layout Schematic of the proposed TORCH MCP TORCH - E N Cowie

Timing σopt = 55ps σpmt = 23ps 𝜎 𝑡𝑜𝑡𝑎𝑙 = 𝜎 2 𝑝𝑚𝑡 + 𝜎 2 𝑜𝑝𝑡 ~60𝑝𝑠 21 November 2018 Timing σopt = 55ps σpmt = 23ps MCP timing spectrum Optics timing spectrum 𝜎 𝑡𝑜𝑡𝑎𝑙 = 𝜎 2 𝑝𝑚𝑡 + 𝜎 2 𝑜𝑝𝑡 ~60𝑝𝑠 TORCH - E N Cowie

Performance 21 November 2018 TORCH - E N Cowie Pion ID performance Correct ID Mis-ID Correct ID Mis-ID Pion ID performance Kaon ID performance TORCH - E N Cowie

Conclusions TORCH is a novel combination of DIRC and ToF. 21 November 2018 Conclusions TORCH is a novel combination of DIRC and ToF. Designed for LHCb but principle can be adapted. Target is 10-15 ps pre track, < 70 ps per photon. R&D project for MCP is ongoing. TORCH - E N Cowie

Viewpoint angles: θ=270° φ=0° 21 November 2018 Viewpoint angles: θ=270° φ=0° Thank you for Listening TORCH - E N Cowie

21 November 2018 SPARES TORCH - E N Cowie

21 November 2018 ToF β ALICE ToF β measurements TORCH - E N Cowie

21 November 2018 Reconstruction TORCH - E N Cowie

Start Time Example from PV of same event After removing outliers 21 November 2018 Start Time Example from PV of same event After removing outliers 𝜎 𝑡 0 = 49 534 ps TORCH - E N Cowie

Take all particles from one Primary Vertex 21 November 2018 Take all particles from one Primary Vertex Invert PID logic, assume pions. Any outliers are then removed. Combining information can achieve ~ few ps resolution TORCH - E N Cowie

21 November 2018 Simulation Output TORCH - E N Cowie

Simulation Output Factor # photons None 254 Mirror 193 +CE 126 21 November 2018 Simulation Output Factor # photons None 254 Mirror 193 +CE 126 +QE 26.3 +Epotek 301 12.0 TORCH - E N Cowie

Simulation Output Factor # photons None 139 Mirror 109 +CE 70.9 21 November 2018 Simulation Output Factor # photons None 139 Mirror 109 +CE 70.9 +QE 14.4 +Epotek 7.03 TORCH - E N Cowie

21 November 2018 Simulation Output TORCH - E N Cowie

Effects of Modular Design 21 November 2018 Effects of Modular Design Module considered Without dispersion or reflection off lower edge Including dispersion and reflection off lower edge TORCH - E N Cowie

21 November 2018 MCP Development TORCH - E N Cowie

21 November 2018 Bristol Test Stand TORCH - E N Cowie

06 March 2014 Diode σ~4.25 ps TORCH Meeting, Oxford, March 2014

06 March 2014 30% σ~41.6 ps TORCH Meeting, Oxford, March 2014