scholarly journals Near-field microwave magnetic nanoscopy of superconducting radio frequency cavity materials

2014 ◽  
Vol 104 (23) ◽  
pp. 232603 ◽  
Author(s):  
Tamin Tai ◽  
Behnood G. Ghamsari ◽  
Thomas R. Bieler ◽  
Teng Tan ◽  
X. X. Xi ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Near Field ◽  
Superconducting Radio Frequency

Development of a 1497-MHz, 13.5-kW Continuous-Wave Magnetron for Superconducting Radio Frequency Accelerator

2021 ◽  
pp. 1-9
Author(s):  
Wenliang Li ◽  
Pengjiao Zhang ◽  
Bowen Zhou ◽  
Hong Zhang ◽  
Youchun Liu ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Continuous Wave ◽  
Superconducting Radio Frequency

scholarly journals Long lifetime of bialkali photocathodes operating in high gradient superconducting radio frequency gun

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
E. Wang ◽  
V. N. Litvinenko ◽  
I. Pinayev ◽  
M. Gaowei ◽  
J. Skaritka ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Electron Beams ◽  
Spot Size ◽  
Laser Spot ◽  
Laser Spot Size ◽  
High Quantum Efficiency ◽  
High Brightness ◽  
High Charge ◽  
Superconducting Radio Frequency ◽  
Long Lifetime

AbstractHigh brightness, high charge electron beams are critical for a number of advanced accelerator applications. The initial emittance of the electron beam, which is determined by the mean transverse energy (MTE) and laser spot size, is one of the most important parameters determining the beam quality. The bialkali photocathodes illuminated by a visible laser have the advantages of high quantum efficiency (QE) and low MTE. Furthermore, Superconducting Radio Frequency (SRF) guns can operate in the continuous wave (CW) mode at high accelerating gradients, e.g. with significant reduction of the laser spot size at the photocathode. Combining the bialkali photocathode with the SRF gun enables generation of high charge, high brightness, and possibly high average current electron beams. However, integrating the high QE semiconductor photocathode into the SRF guns has been challenging. In this article, we report on the development of bialkali photocathodes for successful operation in the SRF gun with months-long lifetime while delivering CW beams with nano-coulomb charge per bunch. This achievement opens a new era for high charge, high brightness CW electron beams.

scholarly journals Uses of radio emission spectroscopy for non-contact and in situ diagnostics of low pressure radio frequency plasma processing

2021 ◽  
Author(s):  
Rajani K. Vijayaraghavan ◽  
Sean Kelly ◽  
David Coates ◽  
Cezar Gaman ◽  
Niall MacGearailt ◽  
...  
Keyword(s):  
Radio Emission ◽  
Radio Frequency ◽  
Emission Spectroscopy ◽  
Near Field ◽  
Plasma Processing ◽  
Diagnostic Technique ◽  
Primary Source ◽  
Low Pressure ◽  
Chamber Pressure ◽  
Rf Plasma

Abstract We demonstrate that a passive non-contact diagnostic technique, radio emission spectroscopy (RES), provides a sensitive monitor of currents in a low pressure radio frequency (RF) plasma. A near field magnetic loop antenna was used to capture RF emissions from the plasma without perturbing it. The analysis was implemented for a capacitively coupled RF plasma with an RF supply at a frequency of 13.56 MHz. Real-time measurements are captured in scenarios relevant to contemporary challenges faced during semiconductor fabrication (e.g. window coating and wall disturbance). Exploration of the technique for key equipment parameters including applied RF power, chamber pressure, RF bias frequencies and chamber wall cleanliness shows sensitive and repeatable function. In particular, the induced RES signal was found to vary sensitively to pressure changes and we were able to detect pressure and power variations as low as ~2.5 %/mtorr and ~3.5 %/watt, respectively, during the plasma processing during a trial generic plasma process. Finally, we explored the ability of RES to monitor the operation of a multiple frequency low-pressure RF plasma system (f1 = 2 MHz, f2 = 162 MHz) and intermixing products which suggests strongly that the plasma sheaths are the primary source of this non-linear diode mixing effect.

scholarly journals Design and Development Of Lecturer Attendance System Using Radio Frequency Identification (RFID)

2021 ◽  
Vol 10 (1) ◽  
pp. 15-27
Author(s):  
I Gede Sujana Eka Putra ◽  
Anthony Lee ◽  
I Made Tirta Mahayana ◽  
I Gede Agung Wicaksono Dharmayasa
Keyword(s):  
Radio Frequency ◽  
Radio Frequency Identification ◽  
Web Application ◽  
Academic Staff ◽  
Near Field ◽  
Literature Study ◽  
Master Data ◽  
Presence Data ◽  
Frequency Identification ◽  
The University

Lecturer attendance record is required by the university to know the presence of lecturers in teaching in class. In general condition, lecturer attendance is recorded on the attendance sheet, or input to web application accessed on a class computer. However, there are some problems in its implementation so that at the end, lecturer presence is carried out using a manual form where the academic staff needs to re-enter the lecturer attendance data into the applications. Based on the above, the authors designed and developed a lecturer attendance information system to record lecturers' attendance using radio frequency identification technology by implementing a near field communication card (NFC Card). The device used to record and read presence data during lectures, by tapping an Mi-fare NFC card to an NFC reader / writer device. The flow of this research method begins with a literature study of NFC card, observe the flow of lecture attendance process and data recorded into lecturer attendance sheet, analyzing the database design, the system design which has compatible with NFC reader and writer devices, designed system interface and continue to develop system. The result is system consists of master data, system attendance, verification and reporting module. The results show that NFC card implementation is more practical for lecturers in conducting lecture attendance and NFC card could be tapped out into an NFC device at a maximum distance up to 7 cm with the reading angle relative to NFC reader/writer with range 00 until 300 can read NFC Card.

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