scholarly journals Near-field effects of Cherenkov radiation induced by ultra high energy cosmic neutrinos

2012 ◽  
Vol 35 (7) ◽  
pp. 421-434 ◽  
Author(s):  
Chia-Yu Hu ◽  
Chih-Ching Chen ◽  
Pisin Chen
2021 ◽  
Vol 3 (Supplement_3) ◽  
pp. iii22-iii22
Author(s):  
Anna L Price ◽  
Russell Holden ◽  
James J H Park ◽  
Denise Dunn ◽  
Brendan Koch ◽  
...  

Abstract Radiation therapy is a mainstay in the treatment of brain metastasis, yet some tumors are resistant, and elsewhere brain recurrence outside the radiation field is common. Phototherapy using UV light-activated compounds can both kill cancer cells directly and trigger an immune response to extend tumor control. Poor penetration depth of ultraviolet light, however, has limited this treatment to superficial tumors. High-energy photon beams create high energy electrons within the patient which in turn produce Cherenkov radiation in the UV spectrum while traveling through tissue. Given that this Cherenkov radiation is generated deep within the patient and has the ability to activate photosensitive compounds, we therefore developed a platform to test this phenomenon to enhance radiation therapy for brain metastasis. We first tested UV-activated psoralen derivatives in combination with UV light in vitro for activity against murine 4T1 breast cancer cells, and then irradiated an ex vivo organotypic brain slice platform using a high energy linear accelerator to generate Cherenkov radiation. We tested the survival of 4T1 cells expressing fluorescent and bioluminescent reports in the presence and absence of these psoralen compounds in this ex vivo brain metastasis model. 8-methoxypsoralen (8-MOP) and 4’-Aminomethyltrioxsalen hydrochloride (AMT) both showed 365nm UVA light-specific cell killing in vitro. We optimized AMT cell loading (1 hour) and concentrations [1μM] AMT to maximize cytotoxicity. Testing of AMT using the organotypic brain slice platform and high-energy irradiation to generate Cherenkov-UV light demonstrated similar enhanced cell death of 4T1 cells despite high baseline levels of radiation-induced tumor cell kill. Cherenkov radiation-induced photo-activation of AMT improved cell killing in an ex vivo model of breast cancer brain metastasis. This application holds promise for the re-treatment of refractory tumors with high-energy, low dose radiation, and enhanced elsewhere brain metastasis control through activation of the immune system.


2013 ◽  
Vol 28 (02) ◽  
pp. 1340006
Author(s):  
CHIA-YU HU ◽  
CHIH-CHING CHEN ◽  
PISIN CHEN

The radio technique of cosmogenic neutrino detection, which relies on the Cherenkov signals coherently emitted from the particle showers in dense medium, has now become a mature field. We present an alternative approach to calculate such Cherenkov pulse by a numerical code based on the finite difference time-domain (FDTD) method that does not rely on the far-field approximation. We show that for a shower elongated by the LPM (Landau-Pomeranchuk-Migdal) effect and thus with a multi-peak structure, the generated Cherenkov signal will always be a bipolar and asymmetric waveform in the near-field regime regardless of the specific variations of the multi-peak structure, which makes it a generic and distinctive feature. This should provide an important characteristic signature for the identification of ultra-high energy cosmogenic neutrinos.


2013 ◽  
Vol 28 (02) ◽  
pp. 1340009 ◽  
Author(s):  
CHIH-CHING CHEN ◽  
PISIN CHEN ◽  
CHIA-YU HU ◽  
K.-C. LAI

We propose a new flavor identification method to distinguish mu and tau type ultra high energy cosmic neutrinos (UHECN). Energy loss of leptons in matter is an important information for the detection of neutrinos originated from high energy astrophysical sources. 50 years ago, Askaryan proposed to detect Cherenkov radiowave signals emitted from the negative charge excess of neutrino-induced particle shower. The theory of Cherenkov radiation under Fraunhofer approximation has been widely studied in the past two decades. However, at high energies or for high density materials, electromagnetic shower should be elongated due to the Landau-Pomeranchuck-Migdal (LPM) effect. As such the standard Fraunhofer approximation ceases to be valid when the distance between the shower and the detector becomes comparable with the shower length. Monte Carlo simulations have been performed recently to investigate this regime. Here we adopt the deduced relationship between the radio signal and the cascade development profile to investigate its implication to lepton signatures. Our method provides a straightforward technique to identify the neutrino flavor through the detected Cherenkov signals.


Author(s):  
Charles W. Allen

Irradiation effects studies employing TEMs as analytical tools have been conducted for almost as many years as materials people have done TEM, motivated largely by materials needs for nuclear reactor development. Such studies have focussed on the behavior both of nuclear fuels and of materials for other reactor components which are subjected to radiation-induced degradation. Especially in the 1950s and 60s, post-irradiation TEM analysis may have been coupled to in situ (in reactor or in pile) experiments (e.g., irradiation-induced creep experiments of austenitic stainless steels). Although necessary from a technological point of view, such experiments are difficult to instrument (measure strain dynamically, e.g.) and control (temperature, e.g.) and require months or even years to perform in a nuclear reactor or in a spallation neutron source. Consequently, methods were sought for simulation of neutroninduced radiation damage of materials, the simulations employing other forms of radiation; in the case of metals and alloys, high energy electrons and high energy ions.


2010 ◽  
Vol 69 (18) ◽  
pp. 1615-1622
Author(s):  
R. I. Tsekhmistro ◽  
N. N. Gorobets

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