1. Super High Momentum Spectrometer –
Heavy Gas Cherenkov Detector
MATTHEW STRUGARI
SUPERVISOR: DR. GARTH HUBER
PART 1: JUNE 3, 2016
PART 2: JULY 5, 2016

2. Part 1 June 3, 2016
CHERENKOV RADIATION; REFRACTIVE INDEX; GAS PROPERTIES;
THRESHOLD PRESSURE; CONE ANGLE; TRANSMITTANCE
MATTHEW STRUGARI, 03/06/16 2

3. A Brief Introduction to Cherenkov Radiation
Cherenkov radiation is a phenomenon which occurs when a charged particle’s velocity (𝑣)
exceeds the light velocity (𝑐 𝑛) within a dielectric medium whose refractive index is 𝑛 > 1.
𝑣 >
𝑐
𝑛
The moving particle polarizes the molecules within the medium.
As the polarized molecules (dipoles) return to their ground state, they oscillate and produce
electric dipole radiation which is known as Cherenkov radiation in this case.
3MATTHEW STRUGARI, 03/06/16

4. Relativistic Equations
Momentum:
𝑝 = 𝛾𝑚𝑣 = 𝛾𝑚𝛽𝑐
where 𝛾 =
1
1 − 𝛽2
is the Lorentz factor, 𝑚 is the particle rest mass, and 𝛽 =
𝑣
𝑐
Energy:
𝐸 = 𝛾𝑚𝑐2
Combining the equations for momentum and energy then solving for 𝛽 yields:
𝛽 =
𝑝𝑐
𝐸
4MATTHEW STRUGARI, 03/06/16

5. Relativistic Equations – cont’d
Energy-Momentum relation:
𝐸2 = 𝑝𝑐 2 + 𝑚c2 2
and 𝛽 as:
𝛽 =
𝑝𝑐
𝑝𝑐 2 + 𝑚𝑐2 2
5MATTHEW STRUGARI, 03/06/16

6. Relativistic Equations – cont’d
Recall that for Cherenkov radiation emission to occur:
𝑣 >
𝑐
𝑛
This can be written in terms of 𝛽 and 𝑛 such that
𝑛 >
1
𝛽
or
𝑛 >
𝑝𝑐 2 + 𝑚𝑐2 2
𝑝𝑐
MATTHEW STRUGARI, 03/06/16 6

7. Threshold Index of Refraction
MATTHEW STRUGARI, 03/06/16 7
Particle Mass 𝒎 (MeV/c2)
Electron 0.511
Pion 139.57
Kaon 493.67
Proton 938.27
Index of Refraction: 𝑛 >
𝑝𝑐 2+ 𝑚𝑐2 2
𝑝𝑐

8. Properties of Gases
Name Formula
Molecular Weight
M (g/mol)
Density
ρ (kg/m3)
Boiling Point
Tb (o
C)
Vapour Pressure
Pv (bar)
Index of Refraction
n
Octafluorotetrahydrofuran C4F8O 216.031
9.338 @ 0o
C & 1.013bar1
-0.8o
C @ 1.013bar1
2.12 @ 20o
C1 1.001392
@ 400nm, 22o
C, & 1.013bar4
8.660 @ 15o
C & 1bar1
Decafluorobutane C4F10 238.032
11.21 @ -1.7o
C & 1.013 bar2
-1.7o
C @ 1.013bar2
1.12 @ 0o
C3
1.001424
@ 400nm, 0o
C, & 1.013bar51.64 @ 10.1o
C3
10.06 @ 15o
C & 1.013 bar2
2.32 @ 20o
C3
Octafluorocyclobutane C4F8 200.0311
9.338 @ 0oC & 1.013bar1
-5.98o
C @ 1.013bar1
1.31 @ 0o
C1
1.001285
@ 589.29nm, 0o
C, & 1.013bar68.771 @ 15oC & 1bar1 1.90@ 10o
C1
8.284 @ 21.1o
C & 1bar1
2.69 @ 20o
C1
Carbon Dioxide CO2 44.0101
1.977 @ 0oC & 1.013bar1
-78.5o
C @ 1.013bar
(Sublimation point)1
34.8 @ 0o
C1
1.000459
@ 400nm, 0o
C, & 1.013bar71.848 @ 15o
C & 1bar1
45.0 @ 10o
C1
1.823 @ 21.1o
C & 1.013bar1
57.3 @ 20o
C1
MATTHEW STRUGARI, 03/06/16 8
1 H. Schoen, Handbook of Purified Gases. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015.
2 “Air Liquide Gas Encyclopedia,” Air Liquide, 2013. [Online]. Available:
http://encyclopedia.airliquide.com/encyclopedia.asp?LanguageID=11&CountryID=19&Formula=c4f10&btnFormula.x=0&btnFormula.y=0&GasID=0&UNNumber=.
3 R. Fowler, J. Hamilton, Jr., J. Kasper, C. Weber, W. Burford III, and H. Anderson, “Physical and Chemical Properties of Pure Fluorocarbons,” Industrial & Engineering Chemistry, vol. 39, no. 3, pp. 375–378, Mar. 1947.
4 E. Fuchey, “C4F8O Index of Refraction,” E-mail. Jun-2016.
5 O. Ullaland, “Fluid systems for RICH detectors,” Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 553, no. 1–2, pp. 107–113, Nov. 2005.
6 V. P. Zrelov, Cherenkov Radiation in High-Energy Physics. Part II Cherenkov Counters: Determination of Energy and Direction of Elementary Particles. Israel Proram from Scientific Translations Ltd. 1970.
7 A. Bideau-Mehu, Y. Guern, R. Abjean, and A. Johannin-Gilles, “Interferometric determination of the refractive index of carbon dioxide in the ultraviolet region,” Optics Communications, vol. 9, no. 4, pp. 432–434, Dec. 1973.

9. Threshold Pressure
MATTHEW STRUGARI, 03/06/16 9
C4F8O: 𝑛1𝑎𝑡𝑚 = 1.001389
C4F10: 𝑛1𝑎𝑡𝑚 = 1.001424
CO2: 𝑛1𝑎𝑡𝑚 = 1.000459
Gas Pressure: 𝑃 =
𝑛−1
𝑛1𝑎𝑡𝑚 −1
=
𝑝𝑐 2+ 𝑚𝑐2 2
𝑝𝑐
−1
𝑛1𝑎𝑡𝑚 −1
 Operating pressure is assumed to be 1atm until
the intercept with the Cherenkov threshold
boundary upon which the operating pressure
follows a tangent to that point (solid black line).

10. Cherenkov Radiation Angle: Pion
MATTHEW STRUGARI, 03/06/16 10
C4F8O:
C4F10:
CO2:
Cone Angle: 𝜃𝑐 = cos−1
(
1
𝛽𝑛
)
 Index of refraction is a function of pressure.
Therefore, the decrease in the cone angle is due to
the reduction of operating pressure at the
threshold boundary.

11. Cherenkov Radiation Angle: Electron
MATTHEW STRUGARI, 03/06/16 11
C4F8O:
C4F10:
CO2:
Cone Angle: 𝜃𝑐 = cos−1
(
1
𝛽𝑛
)
 Index of refraction is a function of pressure.
Therefore, the decrease in the cone angle is due to
the reduction of operating pressure at the
threshold boundary.

12. Transmittance
MATTHEW STRUGARI, 03/06/16 12
C4F8O:8 C4F10:9
8 M. Artuso, C. Boulahouache, S. Blusk, J. Butt, O. Dorjkhaidav, N. Menaa, R. Mountain, H. Muramatsu, R. Nandakumar, K. Randrianarivony, R. Sia, T. Skwarnicki, S. Stone, J. C. Wang, and K.
Zhang, “Performance of a gas radiator ring imaging Cherenkov detector using multi-anode photomultiplier tubes,” Nuclear Instruments and Methods in Physics Research Section A: Accelerators,
Spectrometers, Detectors and Associated Equipment, vol. 558, no. 2, pp. 373–387, Mar. 2006.
• BTeV measurements are for 180-250nm. Below this range, 100-158nm: uses C4F10 transmission measured by the HADES Collab, 163-170nm: shift C4F10 upwards by 10nm and scale by
0.955/0.98 to match
9 P. Fauland, The COMPASS experiment and the RICH-1 detector, Bielefeld (Germany): Bielefeld University, 2004.
• Measured by the HADES Collaboration, normalized to 40cm-bar

13. Transmittance – CO2
MATTHEW STRUGARI, 03/06/16 13
Total Cross Section:10 Transmittance:
10 D. E. Shemansky, “CO2 Extinction Coefficient 1700–3000 Å,” The Journal of Chemical Physics, vol. 56, no. 4, p. 1582, 1972.
Transmittane: 𝑇 = 𝑒−𝑐𝑙𝜎
where 𝑐 = concentration (mol/cm3), 𝑙 = path length (normalized to 100cm), and 𝜎 = total cross section (cm2/mol)

14. Future Work
Perform Geant4 (Monte Carlo) simulations needed to finalize the expected performance of the
SHMS Heavy Gas Cherenkov detector for distinguishing different particle types
Provide assistance with the preparation of the official detector documentation for Jefferson Lab
MATTHEW STRUGARI, 03/06/16 14

15. Special Thanks
University of Regina Jefferson Lab
• Dr. Garth Huber • Brad Sawatzky
• Wenliang Li • Mark Jones
• Sparro Group • Simona Malace
Canadian Institute of Nuclear Physics
• Dr. Jean Barrette
• Dr. Barry Davids
• Dr. Jason Donev
MATTHEW STRUGARI, 03/06/16 15

16. References
1 H. Schoen, Handbook of Purified Gases. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015.
2 “Air Liquide Gas Encyclopedia,” Air Liquide, 2013. [Online]. Available:
http://encyclopedia.airliquide.com/encyclopedia.asp?LanguageID=11&CountryID=19&Formula=c4f10&btnFormula.x=0&btnFormula.y=0&GasID=0&UNNumber=.
3 R. Fowler, J. Hamilton, Jr., J. Kasper, C. Weber, W. Burford III, and H. Anderson, “Physical and Chemical Properties of Pure Fluorocarbons,” Industrial & Engineering Chemistry, vol. 39, no. 3, pp.
375–378, Mar. 1947.
4 M. Artuso, C. Boulahouache, S. Blusk, J. Butt, O. Dorjkhaidav, N. Menaa, R. Mountain, H. Muramatsu, R. Nandakumar, K. Randrianarivony, R. Sia, T. Skwarnicki, S. Stone, J. C. Wang, and K.
Zhang, “Performance of a gas radiator
ring imaging Cherenkov detector using multi-anode photomultiplier tubes,” Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and
Associated Equipment, vol. 558, no. 2, pp. 373–387, Mar. 2006.
5 O. Ullaland, “Fluid systems for RICH detectors,” Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 553,
no. 1–2, pp. 107–113, Nov. 2005.
6 V. P. Zrelov, Cherenkov Radiation in High-Energy Physics. Part II Cherenkov Counters: Determination of Energy and Direction of Elementary Particles. Israel Proram from Scientific Translations
Ltd. 1970.
7 A. Bideau-Mehu, Y. Guern, R. Abjean, and A. Johannin-Gilles, “Interferometric determination of the refractive index of carbon dioxide in the ultraviolet region,” Optics Communications, vol. 9,
no. 4, pp. 432–434, Dec. 1973.
8 M. Artuso, C. Boulahouache, S. Blusk, J. Butt, O. Dorjkhaidav, N. Menaa, R. Mountain, H. Muramatsu, R. Nandakumar, K. Randrianarivony, R. Sia, T. Skwarnicki, S. Stone, J. C. Wang, and K.
Zhang, “Performance of a gas radiator ring imaging Cherenkov detector using multi-anode photomultiplier tubes,” Nuclear Instruments and Methods in Physics Research Section A: Accelerators,
Spectrometers, Detectors and Associated Equipment, vol. 558, no. 2, pp. 373–387, Mar. 2006.
9 P. Fauland, ”The COMPASS experiment and the RICH-1 detector,” Bielefeld (Germany): Bielefeld University, 2004.
10 D. E. Shemansky, “CO2 Extinction Coefficient 1700–3000 Å,” The Journal of Chemical Physics, vol. 56, no. 4, p. 1582, 1972.
MATTHEW STRUGARI, 03/06/16 16

17. Part 2 July 5, 2016
E/PI SEPARATION; PI/K SEPARATION; PMT FOCUSING
MATTHEW STRUGARI, 05/07/16 17

18. e/pi Separation
•Study:
• e/pi separation at low momenta
•Goals:
• Maximize electron Cherenkov radiation efficiency
• Minimize pion Cherenkov radiation efficiency
•Simulation Parameters:
• Number of events: 200000
• Gas: C4F10 and CO2
• Particles: e; k; p; pi
• Momenta (GeV/c): 1.5; 3.0; 5.0; 7.0
• Pressure range: 0.25atm to 0.95atm
MATTHEW STRUGARI, 05/07/16 18

19. MATTHEW STRUGARI, 05/07/16 19C4F10 – e/pi Event Distribution
Increasing Momentum
IncreasingPressure

20. MATTHEW STRUGARI, 05/07/16 20C4F10 – Particle Efficiency and Ratio
Increasing Pressure

21. MATTHEW STRUGARI, 05/07/16 21CO2 – e/pi Event Distribution
Increasing Momentum
IncreasingPressure

22. MATTHEW STRUGARI, 05/07/16 22CO2 – Particle Efficiency and Ratio
Increasing Pressure

23. pi/k Separation
•Study:
• pi/k separation at intermediate momenta
•Goals:
• Maximize pion Cherenkov radiation efficiency
• Minimize kaon Cherenkov radiation efficiency
•Simulation Parameters:
• Number of events: 200000
• Gas: C4F10 and CO2
• Particles: e; k; p; pi
• Momenta (GeV/c): 1.5; 3.0; 5.0; 7.0
• Pressure range: 0.25atm to 0.95atm
MATTHEW STRUGARI, 05/07/16 23

24. MATTHEW STRUGARI, 05/07/16 24C4F10 – pi/k Event Distribution
Increasing Momentum
IncreasingPressure

25. MATTHEW STRUGARI, 05/07/16 25C4F10 – Particle Ratio
Increasing Pressure

26. MATTHEW STRUGARI, 05/07/16 26CO2 – pi/k Event Distribution
Increasing Momentum
IncreasingPressure

27. MATTHEW STRUGARI, 05/07/16 27CO2 – Particle Ratio
Increasing Pressure

28. MATTHEW STRUGARI, 05/07/16 28PMT Focusing – e in CO2
Pressure: 0.35atm
Momentum:7.0GeV/cMomentum:1.5GeV/c
Pressure: 0.75atmPressure: 0.50atm

29. MATTHEW STRUGARI, 05/07/16 29PMT Focusing – pi in C4F10
Pressure: 0.25atm
Momentum:7.0GeV/cMomentum:1.5GeV/c
Pressure: 0.95atmPressure: 0.50atm

30. Future Work
Perform a study on individual PMT results as well as a study in mirror misalignment
Provide assistance with the preparation of the official detector documentation for Jefferson Lab
MATTHEW STRUGARI, 05/07/16 30

31. Special Thanks
University of Regina Jefferson Lab
• Dr. Garth Huber • Brad Sawatzky
• Wenliang Li • Mark Jones
• Sparro Group • Simona Malace
Canadian Institute of Nuclear Physics
• Dr. Jean Barrette
• Dr. Barry Davids
• Dr. Jason Donev
MATTHEW STRUGARI, 05/07/16 31

32. Index of Refraction Formulae
Sellmeier Equation: C4F10
𝑛 − 1 × 106 =
0.25324
(73.7−2−𝜆−2)
(𝜆 in nm)
twiki.cern.ch/twiki/bin/view/LHCb/C4F10
Dispersion Formula: CO2
𝑛 − 1 =
6.99100×10−2
(166.175−𝜆−2)
+
1.47720×10−3
(79.609−𝜆−2)
+
6.42941×10−5
(56.3064−𝜆−2)
+
5.21306×10−5
(46.0196−𝜆−2)
+
1.46847×10−6
(0.0584738−𝜆−2)
(𝜆 in µm)
•Dispersion formula numerators are oscillator strengths of the transitions, numerical terms of
denominator are the wavenumbers of the corresponding absorption bands
•“Interferometric determination of the refractive index of carbon dioxide in the ultraviolet region”
MATTHEW STRUGARI, 03/06/16 32