Ultrafast compact classical Mott polarimeter

Abstract

An ultrafast compact classical Mott detector is described. The efficiency of the polarimeter is epsilon = 6 x 10(-4) and the maximum counting rate approximately 2000 kcps. The Mott polarimeter employs photomultipliers with scintillators as electron energy sensitive detectors with low dark noise. The photomultipliers and scintillators are placed in vacuum. With this choice of technology, it will be possible to build a classical Mott detector with a bulk size of cubic decimeter in the future.

Spin and angle resolved photoemission on non-magnetic low-dimensional systems

“…The main advantage of this type of Mott detector is its high stability and reliability. The main disadvantage that the polarimeter was very large because high voltages were used in order to be able to discriminate the background from the signal, has been resolved due to developments in detection technology [20]. The other main disadvantage is that the detectors, pre-amplifiers and discriminators are all at high voltage which results in rather complex electronics where not all standard components can be easily integrated.…”

Spin-Resolved Valence Photoemission

“…For this reason, Petrov and coworkers have been active in combining various electron energy analyzers with compact spherical high-energy Mott polarimeters [15,31,45,46]; they have also performed comparative tests of this type of polarimeter with the retarding-potential Mott polarimeter [41].…”

“…The early polarimeters, now generally referred to as "classical" Mott polarimeters, were bulky (typically several cubic meters) as electron energies of around 100 keV were involved for both scattering and detection. A modern classical Mott polarimeter has been developed and fully characterized by Petrov [45,46]. This instrument (which is commercially available; see "Commercially Available Polarimeters") has a spherical geometry and is used, inter alia, for photoemission studies on the Swiss Light Source where it has proved to be very reliable.…”

Concept of a multichannel spin-resolving electron analyzer based on Mott scattering

“…The Mott spin detectors (for entries see Petrov et al, 1997Petrov et al, , 2007Hoesch et al, 2002) are based on quasielastic scattering of high-energy electrons (about 40 keV) from a target of a high-Z material such as Au. As a spin selective process, the Mott scattering is characterized by a FOM value of about 6 Â 10 À4 per one spin projection (Petrov et al, 1997(Petrov et al, , 2007 measured by two opposite electron detectors working simultaneously.…”

“…The Mott spin detectors (for entries see Petrov et al, 1997Petrov et al, , 2007Hoesch et al, 2002) are based on quasielastic scattering of high-energy electrons (about 40 keV) from a target of a high-Z material such as Au. As a spin selective process, the Mott scattering is characterized by a FOM value of about 6 Â 10 À4 per one spin projection (Petrov et al, 1997(Petrov et al, , 2007 measured by two opposite electron detectors working simultaneously. Other spin selective processes such as the lowenergy electron reflectivity from W(100) or Ir(100) Kutnyakhov et al, 2013;Vasilyev et al, 2015;Kolbe et al, 2011) or exchange scattering from the Fe 2 O 3 surface (Okuda et al, 2008(Okuda et al, , 2011 may certainly have larger FOM values, in the latter case reaching 9.5 Â 10 À3 per one spin projection (Okuda et al, 2008) acquired in two successive measurements under re-magnetization of the target or sample.…”