The Radiation of Charged Particles in Inhomogeneous Media and its Applications

The cross section for bremsstrahlung from highly relativistic particles is suppressed due to interference caused by multiple scattering in dense media, and due to photon interactions with the electrons in all materials. We present here a detailed study of bremsstrahlung production of 200 keV to 500 MeV photons from 8 and 25 GeV electrons traversing a variety of target materials. For most targets, we observe the expected suppressions to a good accuracy. We observe that finite thickness effects are important for thin targets.

show abstract

“…This is the QED analog of color screening in QCD [13]. Little previous data exist on this suppression mechanism [14].…”

Section: B Dielectric Suppressionmentioning

confidence: 99%

Bremsstrahlung suppression due to the Landau-Pomeranchuk-Migdal and dielectric effects in a variety of materials

Anthony¹,

Becker‐Szendy²,

Bosted³

et al. 1997

Phys. Rev. D

165

View full text Add to dashboard Cite

show abstract

“…For k E, this momentum transfer is given by 1] 3] q k = p e p 0 e k=c = q (E=c) 2 (mc) 2 q ((E k)=c) 2 (mc) 2 k=c (1) where p e and p 0 e are the electron momenta before and after the interaction respectively, and m is the electron mass. For E m and k E, this simpli es to q k m 2 c 3 k 2E(E k) k 2c 2 (2) where = E=m. The formation length is then l f = h=q k = 2 hc 2 =k:…”

Section: Submitted To Physical Review Lettersmentioning

confidence: 99%

“…It is infrared divergent with a dN=dk X 0 =k, where X 0 is the radiation length. For dielectric suppression, the photon spectrum is suppressed by (k=rE) 2 , changing the Bethe Heitler spectrum to dN=dk k.…”

mentioning

confidence: 99%

Measurement of Dielectric Suppression of Bremsstrahlung

et al. 1996

View full text Add to dashboard Cite

In 1953, Ter-Mikaelian predicted that the bremsstrahlung of low energy photons in a medium is suppressed because of interactions between the produced photon and the electrons in the medium. This suppression occurs because the emission takes place over on a long distance scale, allowing for destructive interference between di erent instantaneous photon emission amplitudes. We present here measurements of bremsstrahlung cross sections of 200 keV to 20 MeV photons produced by 8 and 25 GeV electrons in carbon and gold targets. Our data shows that dielectric suppression occurs at the predicted level, reducing the cross section up to 75% in our data.

show abstract

“…of free-electron radiation, the concept of formation time in a bulk medium was firstly proposed by Ter-Mikaelian in Landau's seminar in 1952, [22,23] and then further developed by Landau himself, [24,25] with its physical effects experimentally demonstrated in 1990s. [26][27][28] Later, Ginzburg extended the formation time concept into photon emission from an interface, namely transition radiation. [8,9,29] As defined by Ginzburg, photons in transition radiation are emitted within one formation time.…”

Section: Introductionmentioning

confidence: 99%

Bulk‐Plasmon‐Mediated Free‐Electron Radiation Beyond the Conventional Formation Time

et al. 2023

View full text Add to dashboard Cite

Free‐electron radiation is a fundamental photon emission process that is induced by fast‐moving electrons interacting with optical media. Historically, it has been understood that, just like any other photon emission process, free‐electron radiation must be constrained within a finite time interval known as the “formation time,” whose concept is applicable to both Cherenkov radiation and transition radiation, the two basic mechanisms describing radiation from a bulk medium and from an interface, respectively. Here, this work reveals an alternative mechanism of free‐electron radiation far beyond the previously defined formation time. It occurs when a fast electron crosses the interface between vacuum and a plasmonic medium supporting bulk plasmons. While emitted continuously from the crossing point on the interface—thus consistent with the features of transition radiation—the extra radiation beyond the conventional formation time is supported by a long tail of bulk plasmons following the electron's trajectory deep into the plasmonic medium. Such a plasmonic tail mixes surface and bulk effects, and provides a sustained channel for electron–interface interaction. These results also settle the historical debate in Ferrell radiation, regarding whether it is a surface or bulk effect, from transition radiation or plasmonic oscillation.

show abstract

The Radiation of Charged Particles in Inhomogeneous Media and its Applications

Cited by 5 publications

References 0 publications

Bremsstrahlung suppression due to the Landau-Pomeranchuk-Migdal and dielectric effects in a variety of materials

Bremsstrahlung suppression due to the Landau-Pomeranchuk-Migdal and dielectric effects in a variety of materials

Measurement of Dielectric Suppression of Bremsstrahlung

Bulk‐Plasmon‐Mediated Free‐Electron Radiation Beyond the Conventional Formation Time

Contact Info

Product

Resources

About