**12. References**

112 Particle Physics

Beam Energy (TeV) Effective Dose Ratio 0.01 0.39 0.1 1.75 1.0 2.16 10. 2.23

The tau collider neutrino effective doses are generally larger than those encountered in a muon collider, and the tau dose profile is also larger. The larger tau profile is demonstrated

105.7

Using Eq. 34 and the Table 7 results for circular tau collider conditions, the neutrino effective dose profile radius at the earth's surface is 60.5, 30.2, 16.8, and 13.4 m for 1, 2, 5, and 10 TeV beams. These affected areas and associated effective doses suggest that the tau collider is a more significant radiation hazard than the muon collider. Therefore, larger

An improved calculation of the neutrino effective dose from a tau collider requires a better specification of neutrino properties. For example, previous calculations were based on the Standard Model assumption that neutrinos have zero mass. Neutrino masses can be calculated assuming the alternative gauge group <sup>2</sup> 2 1 *<sup>L</sup> <sup>R</sup> SU SU U* instead of the Standard Model <sup>2</sup> 1 *<sup>L</sup> SU U* . This gauge group leads to a neutrino generation i mass:

2

*W M*

where Mi is the generation i lepton mass (e, μ, and τ), WR is the right-handed W boson mass (≥ 300 GeV), and g is a coupling constant with a value of 0.585 (Mohapatra & Senjanović, 1980). Using these values in Eq. 35 leads to electron, muon, and tau neutrino upper bound masses of 1.5 eV, 64 keV, and 18 MeV, respectively. These masses affect the input values used to calculate the neutrino effective dose in Eqs. 14 and 23. As an alternative, better cross-

Neutrino radiation will be a health physics issue and design constraint for muon colliders, particularly at TeV energies. TeV energy muon colliders will require careful site selection and the neutrino effective dose may dictate that these machines be constructed in isolated areas. With the operation of TeV energy muon colliders, the neutrino effective dose can no longer be neglected. Neutrino detection, neutrino dosimetry, and the determination of the neutrino effective dose will no longer be academic exercises, but will become operational

*R i*

<sup>1777</sup> 16.8

(34)

*gm* (35)

by considering Eqs. 3 and 4 for equivalent tau and muon collider configurations:

*r m MeV r m MeV* 

 

effective doses and affected areas are anticipated during tau collider operations.

*i*

*m*

section data and dose conversion factors would refine the neutrino effective dose.

**11. Conclusions** 

The results of calculations utilizing Eq. 33 are summarized in Table 8.

Table 8. Ratio of Tau and Muon Collider Neutrino Effective Doses.

 


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