- Email: [email protected]
Design and R&D of RICH detectors for EIC experiments
Author’s Accepted Manuscript Design and R&D of RICH detectors for EIC experiments A. Del Dotto, C.-P. Wong, L. Allison, M. Awadi, B. Azmoun, F. Barbosa, W. Brooks, T. Cao, M. Chiu, E. Cisbani, M. Contalbrigo, A. Datta, M. Demarteau, J.M. Durham, R. Dzhygadlo, D. Fields, Y. Furletova, C. Gleason, M. GrossePerdekamp, J. Harris, X. He, H. van Hecke, T. Horn, J. Huang, C. Hyde, Y. Ilieva, G. Kalicy, M. Kimball, E. Kistenev, Y. Kulinich, M. Liu, R. Majka, J. McKisson, R. Mendez, P. NadelTuronski, K. Park, K. Peters, T. Rao, R. Pisani, Y. Qiang, S. Rescia, P. Rossi, M. Sarsour, C. Schwarz, J. Schwiening, C.L. da Silva, N. Smirnov, H. Stein, J. Stevens, A. Sukhanov, S. Syed, A. Tate, J. Toh, C. Towell, R. Towell, T. Tsang, R. Wagner, J. Wang, C. Woody, W. Xi, J. Xie, Z.W. Zhao, B. Zihlmann, C. Zorn
PII: DOI: Reference:
www.elsevier.com/locate/nima
S0168-9002(17)30372-8 http://dx.doi.org/10.1016/j.nima.2017.03.032 NIMA59755
To appear in: Nuclear Inst. and Methods in Physics Research, A Received date: 1 November 2016 Revised date: 7 March 2017 Accepted date: 16 March 2017 Cite this article as: A. Del Dotto, C.-P. Wong, L. Allison, M. Awadi, B. Azmoun, F. Barbosa, W. Brooks, T. Cao, M. Chiu, E. Cisbani, M. Contalbrigo, A. Datta, M. Demarteau, J.M. Durham, R. Dzhygadlo, D. Fields, Y. Furletova, C. Gleason, M. Grosse-Perdekamp, J. Harris, X. He, H. van Hecke, T. Horn, J. Huang, C. Hyde, Y. Ilieva, G. Kalicy, M. Kimball, E. Kistenev, Y. Kulinich, M. Liu, R. Majka, J. McKisson, R. Mendez, P. Nadel-Turonski, K. Park, K. Peters, T. Rao, R. Pisani, Y. Qiang, S. Rescia, P. Rossi, M. Sarsour, C. Schwarz, J. Schwiening, C.L. da Silva, N. Smirnov, H. Stein, J. Stevens, A. Sukhanov, S. Syed, A. Tate, J. Toh, C. Towell, R. Towell, T. Tsang, R. Wagner, J. Wang, C. Woody, W. Xi, J. Xie, Z.W. Zhao, B. Zihlmann and C. Zorn, Design and R&D of RICH detectors for EIC experiments, Nuclear Inst. and Methods in Physics Research, A, http://dx.doi.org/10.1016/j.nima.2017.03.032
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Design and R&D of RICH detectors for EIC experiments$ A. Del Dottok,m,∗, C.-P. Wongg , L. Allisono , M. Awadii , B. Azmounc , F. Barbosam , W. Brooksp , T. Caoq , M. Chiuc , E. Cisbanik,l , M. Contalbrigoj , A. Dattar , M. Demarteaub , J.M. Durhamn , R. Dzhygadloh , D. Fieldsr , Y. Furletovam , C. Gleasons , M. Grosse-Perdekampq , J. Harrisf , X. Heg , H. van Hecken , T. Hornd , J. Huangc , C. Hydeo , Y. Ilievas , G. Kalicyd , M. Kimballa , E. Kistenevc , Y. Kulinichq , M. Liun , R. Majkaf , J. McKissonm , R. Mendezn , P. Nadel-Turonskim , K. Parkm , K. Petersh , T. Raoc , R. Pisanic , Y. Qiangm , S. Resciac , P. Rossim , M. Sarsourg , C. Schwarzh , J. Schwieningh , C.L. da Silvan , N. Smirnovt , H. Steina , J. Stevense , A. Sukhanovc , S. Syedg , A. Tatea , J. Tohq , C. Towella , R. Towella , T. Tsangc , R. Wagnerb , J. Wangb , C. Woodyc , W. Xim , J. Xieb , Z.W. Zhaof , B. Zihlmannm , C. Zornm a Abilene
Christian University, Abilene, TX 79601 National Lab, Argonne, IL 60439 c Brookhaven National Lab, Upton, NY 11973 d Catholic University of America, Washington, DC 20064 e College of William & Mary, Williamsburg, VA 2318 f Duke University, Durham, NC 27708 g Georgia State University, Atlanta, GA 30303 h GSI Helmholtzzentrum fr Schwerionenforschung GmbH, 64291 Darmstadt, Germany i Howard University, Washington, DC 20059 j INFN, Sezione di Ferrara, 44100 Ferrara, Italy k INFN, Sezione di Roma, 00185 Rome, Italy l Istituto Superiore di Sanit` a, 00161 Rome, Italy m Jefferson Lab, Newport News, VA 23606 n Los Alamos National Lab, Los Alamos, NM 87545 o Old Dominion University, Norfolk, VA 23529 p Universidad Tcnica Federico Santa Mara, Valparaso, Chile q University of Illinois, UrbanaChampaign, IL 61801 r University of New Mexico, Albuquerque, NM 87131 s University of South Carolina, Columbia, SC 29208 t Yale University, New Haven, CT 06520 b Argonne
Abstract An Electron-Ion Collider (EIC) has been proposed to further explore the strong force and QCD, focusing on the structure and the interaction of gluon-dominated matter. A generic detector R&D program (EIC PID consortium) for the particle identification in EIC experiments was formed to explore technologically advanced solutions in this scope. In this context two Ring Imaging Cherenkov (RICH) counters have been proposed: a modular RICH detector which consists of an aerogel radiator, a Fresnel lens, a mirrored box, and pixelated photon sensor; a dual-radiator RICH, consisting of an aerogel radiator and C2 F6 gas in a mirror-focused configuration. We present the simulations of the two detectors and their estimated performance. Keywords: Electron-Ion Collider, Particle Identification, Ring Imaging Cherenkov 1. Introduction
5
10
The future Electron-Ion Collider (EIC) [1] will be a unique experimental facility for several fundamental topics in the sector of the strong interaction: nucleon tomography and quark 15 orbital angular momentum accessible through the extraction of the generalized parton distributions (GPDs) and transverse momentum dependent parton distribution functions (TMDs), quark hadronization in nuclear medium and hadron spectroscopy. In such a context the capability of particle identi- 20 fication (PID), and in particular hadron ID for several of the $ EIC
Detector R&D Consortium author Email address: [email protected] (A. Del Dotto)
∗ Corresponding
Preprint submitted to Journal of LATEX Templates
25
experimental processes which are targets for EIC, turns out to be extremely important. Three models of the EIC detector are under study at Jefferson Lab (JLab) and Brookhaven National Lab (BNL), with slightly different layouts. The PID consortium is focusing on an integrated solution for the EIC detector. In this context a modular aerogel RICH (mRICH) and a dualradiator RICH (dRICH) have been proposed. Different configurations of both detectors have been modeled and simulated within the GEANT4/GEMC framework [2]. The GEMC simulation is based on realistic optical properties of the latest generation aerogel (tested by the CLAS12 RICH collaboration [3]); absorption length and Rayleigh scattering are included in the simulation, the latter is one of the main source of background and optical dispersion (the spectrum of the Rayleigh scattering is ∝ 1/λ4 , therefore this contribution is important for waveMarch 17, 2017
length of the photons below 300 nm). For the rest the simulations and the parameters used for mRICH and dRICH are almost independent. Details of the simulations and the expected performances are presented in the next sections. 30
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60
65
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2. Modular RICH The modular RICH (mRICH) uses a Fresnel lens to extend momentum coverage up to 10 GeV/c in a limited space (which is the major challenge in the electron-endcap of the EIC detector). The dimension of the first prototype mRICH is 11.5cm × 11.3cm × 11.3cm, which consists of an aerogel radiator, a Fresnel lens, a mirrored box, and a pixelated photon sensor plane, as shown in Fig. 1. The key parameters of each component are: i) aerogel radiator (n=1.03) thickness 3.3 cm ii) focal length of the Fresnel lens 3” (7.62 cm), with n=1.47, iii) the quantum efficiency curve of the multi-anode PMT HamamatsuH8500 has been used. The focusing of a Fresnel lens results in a sharper Cherenkov ring image. This yields a lower uncertainty of single photon measurement which in turn provides greater separation power (number of standard deviation) as shown on Fig. 2. The first prototype mRICH detector has been tested at Fermilab using 120 GeV/c proton beam, as well as 4 and 8 GeV/c secondary pion beam. The working principle of the mRICH was demonstrated and the data analysis is ongoing. 3. Dual-radiator RICH The goal of the dRICH detector is to provide good hadron separation (π/K/p) up to 50 GeV/c. Different focusing geometries have been evaluated by semi-analytical models; a mirrorbased focusing system, similar to the LHCb and HERMES RICHes was eventually selected. The focusing mirror enlarges 80 the momentum coverage capability, in particular for the gas radiator. The readout area in such a design can be more compact, and can be placed in the shadow of a barrel calorimeter. Since the readout is placed outside the radiator acceptance, the total 85 thickness of this arrangement can be small. In this study we benefited from the experience provided by several groups that have built similar devices in the past [4–7], and also by the CLAS12 RICH experience which is in progress [3]. The optimized key parameters are summarized by: i) device 90 length 1.65 m; ii) aerogel radiator (n(400 nm) = 1.02) thickness 4 cm; iii) C2 F6 gas tank length 1.6 m; iv) polar angle coverage [5o , 25o ]; v) mirror radius 2.9 m. The detector is shown in Fig. 3. Photons produced in the aerogel with wavelength below 300 nm have been cut out by software; in the future simulations an acrylic shield will separate the aerogel from the gas, for 95 both shielding and avoiding chemical degradation of the aerogel (see [8]). The mirror reflectivity was assumed to be 95% and flat. The dRICH is in a non-negligible magnetic field and the charged particle tracks are bending as they pass through the Cherenkov radiators, this is an additional source of uncertainty100 in the Cherenkov ring reconstruction. The effect is proportional 2
Figure 1: The modular RICH detector design in GEMC simulation framework. In pink is the Fresnel lens with 100 grooves, focusing the Cherenkov radiation. Four mirrors (blue) are placed at the top, bottom, left, and right of the detector. At the back (in violet) of the detector are photo-sensors and readout electronics. Figure on the bottom shows a single negatively-charged pion passing through the detector. The pion emits Cherenkov photons inside the aerogel. Those photons are focused by the Fresnel lens before arriving at the photo-sensors.
to the path length within the Cherenkov radiators, therefore it becomes particularly important for gas radiator. The magnetic field used in the simulation is the JLab detector design at 3T central field. The pixel size of the readout has been assumed to be 3 mm; the quantum efficiency curve of the multi-anode PMT Hamamatsu-H12700-03 has been also assumed. The reconstruction of the Cherenkov angle is based on the indirect ray tracing algorithm used by the HERMES experiment (see [4] for details on the algorithm). The two upper plots of Fig. 4 report the main error contributions to the single p.e. angular resolution of the two radiators as a function of the charged particle track polar angle. The bottom plot of Fig. 4, shows the PID performances for particles of polar angle of 15o . 4. Conclusions and future directions Simulations and analysis for mRICH and dRICH are still in progress. For mRICH a systematic study of the aerogel and Fresnel lens to optimize the ring image on the sensor plane is underway together with the analysis of the beam test data. The dRICH development will focus on the selection of the photondetector baseline as well as its detailed digitization in the simulation: these aspects are critical due to the presence of the magnetic field. The outlined work will be preparatory for a first dRICH and a second mRICH prototype and test beam.
Acknowledgement: this material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177. 105
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[1] A. Accardi, J. Albacete, M. Anselmino, N. Armesto, E. Aschenauer, A. Bacchetta, D. Boer, W. Brooks, T. Burton, N.-B. Chang, et al., ElectronIon Collider: The next QCD frontier, The European Physical Journal A 52 (9) (2016) 268. doi:10.1140/epja/i2016-16268-9. [2] http://gemc.jlab.org. [3] S. A. Pereira, N. Baltzell, L. Barion, F. Benmokhtar, W. Brooks, E. Cisbani, M. Contalbrigo, A. El Alaoui, K. Hafidi, M. Hoek, et al., Test of the CLAS12 RICH large-scale prototype in the direct proximity focusing configuration, The European Physical Journal A 52 (2) (2016) 1–15. doi:10.1140/epja/i2016-16023-4. [4] N. Akopov, E. Aschenauer, K. Bailey, S. Bernreuther, N. Bianchi, G. Capitani, P. Carter, E. Cisbani, R. De Leo, E. De Sanctis, et al., The HERMES dual-radiator ring imaging cherenkov detector, NIM A 479 (2) (2002) 511– 530. doi:10.1016/S0168-9002(01)00932-9. [5] The LHCb Collaboration, M. Adinolfi, G. A. Rinella, E. Albrecht, T. Bellunato, S. Benson, T. Blake, C. Blanks, S. Brisbane, N. Brook, M. Calvi, et al., Performance of the LHCb RICH detector at the LHC, The European Physical Journal C 73 (5) (2013) 1–17. doi:10.1140/epjc/ s10052-013-2431-9. [6] The LHCb Collaboration, A. A. Alves Jr, L. Andrade Filho, A. Barbosa, I. Bediaga, G. Cernicchiaro, G. Guerrer, H. Lima Jr, A. Machado, J. Magnin, F. Marujo, et al., The LHCb detector at the LHC, Journal of instrumentation 3 (08) (2008) S08005. [7] The LHCb Collaboration, R. A. Nobrega, A. F. Barbosa, I. Bediaga, G. Cernicchiaro, E. C. Oliveira, J. Magnin, J. M. Miranda, A. Massafferri, E. Polycarpo, A. Reis, et al., LHCb reoptimized detector design and performance: Technical Design Report. [8] D. Perego, The lhcb rich silica aerogel performance with lhc data, NIM A 639 (1) (2011) 234–237. doi:10.1016/j.nima.2010.09.119.
momentum (GeV/c)
References
Figure 2: Uncertainty of single photon measurement (upper panel), and separation power (lower panel) from simulation with infinitely small pixel size.
3
Figure 3: The GEMC based simulation of the dRICH. In transparent red is the aerogel radiator, in transparent green is the gas radiator volume; the mirrors sectors are in gray and the photo-detector surfaces (spherical shape) of about 8500 cm2 per sector in dark-yellow. A pion event of momentum 10 GeV/c is simulated.
Figure 4: (Upper two plots) dRICH single p.e. angular error sources, for a 30 GeV/c pion, assuming a pixel size of 3 mm: the detector surface has been chosen to minimize the emission uncertainty for central polar angles, namely the detector surface is nearest to the focal surface for central polar angles. (Lower plot) Particle separation power (in terms of number of sigma) for tracks with 15 polar angle.
4
PII: DOI: Reference:
www.elsevier.com/locate/nima
S0168-9002(17)30372-8 http://dx.doi.org/10.1016/j.nima.2017.03.032 NIMA59755
To appear in: Nuclear Inst. and Methods in Physics Research, A Received date: 1 November 2016 Revised date: 7 March 2017 Accepted date: 16 March 2017 Cite this article as: A. Del Dotto, C.-P. Wong, L. Allison, M. Awadi, B. Azmoun, F. Barbosa, W. Brooks, T. Cao, M. Chiu, E. Cisbani, M. Contalbrigo, A. Datta, M. Demarteau, J.M. Durham, R. Dzhygadlo, D. Fields, Y. Furletova, C. Gleason, M. Grosse-Perdekamp, J. Harris, X. He, H. van Hecke, T. Horn, J. Huang, C. Hyde, Y. Ilieva, G. Kalicy, M. Kimball, E. Kistenev, Y. Kulinich, M. Liu, R. Majka, J. McKisson, R. Mendez, P. Nadel-Turonski, K. Park, K. Peters, T. Rao, R. Pisani, Y. Qiang, S. Rescia, P. Rossi, M. Sarsour, C. Schwarz, J. Schwiening, C.L. da Silva, N. Smirnov, H. Stein, J. Stevens, A. Sukhanov, S. Syed, A. Tate, J. Toh, C. Towell, R. Towell, T. Tsang, R. Wagner, J. Wang, C. Woody, W. Xi, J. Xie, Z.W. Zhao, B. Zihlmann and C. Zorn, Design and R&D of RICH detectors for EIC experiments, Nuclear Inst. and Methods in Physics Research, A, http://dx.doi.org/10.1016/j.nima.2017.03.032
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Design and R&D of RICH detectors for EIC experiments$ A. Del Dottok,m,∗, C.-P. Wongg , L. Allisono , M. Awadii , B. Azmounc , F. Barbosam , W. Brooksp , T. Caoq , M. Chiuc , E. Cisbanik,l , M. Contalbrigoj , A. Dattar , M. Demarteaub , J.M. Durhamn , R. Dzhygadloh , D. Fieldsr , Y. Furletovam , C. Gleasons , M. Grosse-Perdekampq , J. Harrisf , X. Heg , H. van Hecken , T. Hornd , J. Huangc , C. Hydeo , Y. Ilievas , G. Kalicyd , M. Kimballa , E. Kistenevc , Y. Kulinichq , M. Liun , R. Majkaf , J. McKissonm , R. Mendezn , P. Nadel-Turonskim , K. Parkm , K. Petersh , T. Raoc , R. Pisanic , Y. Qiangm , S. Resciac , P. Rossim , M. Sarsourg , C. Schwarzh , J. Schwieningh , C.L. da Silvan , N. Smirnovt , H. Steina , J. Stevense , A. Sukhanovc , S. Syedg , A. Tatea , J. Tohq , C. Towella , R. Towella , T. Tsangc , R. Wagnerb , J. Wangb , C. Woodyc , W. Xim , J. Xieb , Z.W. Zhaof , B. Zihlmannm , C. Zornm a Abilene
Christian University, Abilene, TX 79601 National Lab, Argonne, IL 60439 c Brookhaven National Lab, Upton, NY 11973 d Catholic University of America, Washington, DC 20064 e College of William & Mary, Williamsburg, VA 2318 f Duke University, Durham, NC 27708 g Georgia State University, Atlanta, GA 30303 h GSI Helmholtzzentrum fr Schwerionenforschung GmbH, 64291 Darmstadt, Germany i Howard University, Washington, DC 20059 j INFN, Sezione di Ferrara, 44100 Ferrara, Italy k INFN, Sezione di Roma, 00185 Rome, Italy l Istituto Superiore di Sanit` a, 00161 Rome, Italy m Jefferson Lab, Newport News, VA 23606 n Los Alamos National Lab, Los Alamos, NM 87545 o Old Dominion University, Norfolk, VA 23529 p Universidad Tcnica Federico Santa Mara, Valparaso, Chile q University of Illinois, UrbanaChampaign, IL 61801 r University of New Mexico, Albuquerque, NM 87131 s University of South Carolina, Columbia, SC 29208 t Yale University, New Haven, CT 06520 b Argonne
Abstract An Electron-Ion Collider (EIC) has been proposed to further explore the strong force and QCD, focusing on the structure and the interaction of gluon-dominated matter. A generic detector R&D program (EIC PID consortium) for the particle identification in EIC experiments was formed to explore technologically advanced solutions in this scope. In this context two Ring Imaging Cherenkov (RICH) counters have been proposed: a modular RICH detector which consists of an aerogel radiator, a Fresnel lens, a mirrored box, and pixelated photon sensor; a dual-radiator RICH, consisting of an aerogel radiator and C2 F6 gas in a mirror-focused configuration. We present the simulations of the two detectors and their estimated performance. Keywords: Electron-Ion Collider, Particle Identification, Ring Imaging Cherenkov 1. Introduction
5
10
The future Electron-Ion Collider (EIC) [1] will be a unique experimental facility for several fundamental topics in the sector of the strong interaction: nucleon tomography and quark 15 orbital angular momentum accessible through the extraction of the generalized parton distributions (GPDs) and transverse momentum dependent parton distribution functions (TMDs), quark hadronization in nuclear medium and hadron spectroscopy. In such a context the capability of particle identi- 20 fication (PID), and in particular hadron ID for several of the $ EIC
Detector R&D Consortium author Email address: [email protected] (A. Del Dotto)
∗ Corresponding
Preprint submitted to Journal of LATEX Templates
25
experimental processes which are targets for EIC, turns out to be extremely important. Three models of the EIC detector are under study at Jefferson Lab (JLab) and Brookhaven National Lab (BNL), with slightly different layouts. The PID consortium is focusing on an integrated solution for the EIC detector. In this context a modular aerogel RICH (mRICH) and a dualradiator RICH (dRICH) have been proposed. Different configurations of both detectors have been modeled and simulated within the GEANT4/GEMC framework [2]. The GEMC simulation is based on realistic optical properties of the latest generation aerogel (tested by the CLAS12 RICH collaboration [3]); absorption length and Rayleigh scattering are included in the simulation, the latter is one of the main source of background and optical dispersion (the spectrum of the Rayleigh scattering is ∝ 1/λ4 , therefore this contribution is important for waveMarch 17, 2017
length of the photons below 300 nm). For the rest the simulations and the parameters used for mRICH and dRICH are almost independent. Details of the simulations and the expected performances are presented in the next sections. 30
35
40
45
50
55
60
65
70
75
2. Modular RICH The modular RICH (mRICH) uses a Fresnel lens to extend momentum coverage up to 10 GeV/c in a limited space (which is the major challenge in the electron-endcap of the EIC detector). The dimension of the first prototype mRICH is 11.5cm × 11.3cm × 11.3cm, which consists of an aerogel radiator, a Fresnel lens, a mirrored box, and a pixelated photon sensor plane, as shown in Fig. 1. The key parameters of each component are: i) aerogel radiator (n=1.03) thickness 3.3 cm ii) focal length of the Fresnel lens 3” (7.62 cm), with n=1.47, iii) the quantum efficiency curve of the multi-anode PMT HamamatsuH8500 has been used. The focusing of a Fresnel lens results in a sharper Cherenkov ring image. This yields a lower uncertainty of single photon measurement which in turn provides greater separation power (number of standard deviation) as shown on Fig. 2. The first prototype mRICH detector has been tested at Fermilab using 120 GeV/c proton beam, as well as 4 and 8 GeV/c secondary pion beam. The working principle of the mRICH was demonstrated and the data analysis is ongoing. 3. Dual-radiator RICH The goal of the dRICH detector is to provide good hadron separation (π/K/p) up to 50 GeV/c. Different focusing geometries have been evaluated by semi-analytical models; a mirrorbased focusing system, similar to the LHCb and HERMES RICHes was eventually selected. The focusing mirror enlarges 80 the momentum coverage capability, in particular for the gas radiator. The readout area in such a design can be more compact, and can be placed in the shadow of a barrel calorimeter. Since the readout is placed outside the radiator acceptance, the total 85 thickness of this arrangement can be small. In this study we benefited from the experience provided by several groups that have built similar devices in the past [4–7], and also by the CLAS12 RICH experience which is in progress [3]. The optimized key parameters are summarized by: i) device 90 length 1.65 m; ii) aerogel radiator (n(400 nm) = 1.02) thickness 4 cm; iii) C2 F6 gas tank length 1.6 m; iv) polar angle coverage [5o , 25o ]; v) mirror radius 2.9 m. The detector is shown in Fig. 3. Photons produced in the aerogel with wavelength below 300 nm have been cut out by software; in the future simulations an acrylic shield will separate the aerogel from the gas, for 95 both shielding and avoiding chemical degradation of the aerogel (see [8]). The mirror reflectivity was assumed to be 95% and flat. The dRICH is in a non-negligible magnetic field and the charged particle tracks are bending as they pass through the Cherenkov radiators, this is an additional source of uncertainty100 in the Cherenkov ring reconstruction. The effect is proportional 2
Figure 1: The modular RICH detector design in GEMC simulation framework. In pink is the Fresnel lens with 100 grooves, focusing the Cherenkov radiation. Four mirrors (blue) are placed at the top, bottom, left, and right of the detector. At the back (in violet) of the detector are photo-sensors and readout electronics. Figure on the bottom shows a single negatively-charged pion passing through the detector. The pion emits Cherenkov photons inside the aerogel. Those photons are focused by the Fresnel lens before arriving at the photo-sensors.
to the path length within the Cherenkov radiators, therefore it becomes particularly important for gas radiator. The magnetic field used in the simulation is the JLab detector design at 3T central field. The pixel size of the readout has been assumed to be 3 mm; the quantum efficiency curve of the multi-anode PMT Hamamatsu-H12700-03 has been also assumed. The reconstruction of the Cherenkov angle is based on the indirect ray tracing algorithm used by the HERMES experiment (see [4] for details on the algorithm). The two upper plots of Fig. 4 report the main error contributions to the single p.e. angular resolution of the two radiators as a function of the charged particle track polar angle. The bottom plot of Fig. 4, shows the PID performances for particles of polar angle of 15o . 4. Conclusions and future directions Simulations and analysis for mRICH and dRICH are still in progress. For mRICH a systematic study of the aerogel and Fresnel lens to optimize the ring image on the sensor plane is underway together with the analysis of the beam test data. The dRICH development will focus on the selection of the photondetector baseline as well as its detailed digitization in the simulation: these aspects are critical due to the presence of the magnetic field. The outlined work will be preparatory for a first dRICH and a second mRICH prototype and test beam.
Acknowledgement: this material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177. 105
References
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σθ (mrad)
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[1] A. Accardi, J. Albacete, M. Anselmino, N. Armesto, E. Aschenauer, A. Bacchetta, D. Boer, W. Brooks, T. Burton, N.-B. Chang, et al., ElectronIon Collider: The next QCD frontier, The European Physical Journal A 52 (9) (2016) 268. doi:10.1140/epja/i2016-16268-9. [2] http://gemc.jlab.org. [3] S. A. Pereira, N. Baltzell, L. Barion, F. Benmokhtar, W. Brooks, E. Cisbani, M. Contalbrigo, A. El Alaoui, K. Hafidi, M. Hoek, et al., Test of the CLAS12 RICH large-scale prototype in the direct proximity focusing configuration, The European Physical Journal A 52 (2) (2016) 1–15. doi:10.1140/epja/i2016-16023-4. [4] N. Akopov, E. Aschenauer, K. Bailey, S. Bernreuther, N. Bianchi, G. Capitani, P. Carter, E. Cisbani, R. De Leo, E. De Sanctis, et al., The HERMES dual-radiator ring imaging cherenkov detector, NIM A 479 (2) (2002) 511– 530. doi:10.1016/S0168-9002(01)00932-9. [5] The LHCb Collaboration, M. Adinolfi, G. A. Rinella, E. Albrecht, T. Bellunato, S. Benson, T. Blake, C. Blanks, S. Brisbane, N. Brook, M. Calvi, et al., Performance of the LHCb RICH detector at the LHC, The European Physical Journal C 73 (5) (2013) 1–17. doi:10.1140/epjc/ s10052-013-2431-9. [6] The LHCb Collaboration, A. A. Alves Jr, L. Andrade Filho, A. Barbosa, I. Bediaga, G. Cernicchiaro, G. Guerrer, H. Lima Jr, A. Machado, J. Magnin, F. Marujo, et al., The LHCb detector at the LHC, Journal of instrumentation 3 (08) (2008) S08005. [7] The LHCb Collaboration, R. A. Nobrega, A. F. Barbosa, I. Bediaga, G. Cernicchiaro, E. C. Oliveira, J. Magnin, J. M. Miranda, A. Massafferri, E. Polycarpo, A. Reis, et al., LHCb reoptimized detector design and performance: Technical Design Report. [8] D. Perego, The lhcb rich silica aerogel performance with lhc data, NIM A 639 (1) (2011) 234–237. doi:10.1016/j.nima.2010.09.119.
momentum (GeV/c)
References
Figure 2: Uncertainty of single photon measurement (upper panel), and separation power (lower panel) from simulation with infinitely small pixel size.
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Figure 3: The GEMC based simulation of the dRICH. In transparent red is the aerogel radiator, in transparent green is the gas radiator volume; the mirrors sectors are in gray and the photo-detector surfaces (spherical shape) of about 8500 cm2 per sector in dark-yellow. A pion event of momentum 10 GeV/c is simulated.
Figure 4: (Upper two plots) dRICH single p.e. angular error sources, for a 30 GeV/c pion, assuming a pixel size of 3 mm: the detector surface has been chosen to minimize the emission uncertainty for central polar angles, namely the detector surface is nearest to the focal surface for central polar angles. (Lower plot) Particle separation power (in terms of number of sigma) for tracks with 15 polar angle.
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