Detekcija teških iona pomoću emisije sekundarnih elektrona

master's thesis

• Title (english): Heavy-ion detection by secondary electron emission
• Author: Ivana Retkovac Šešelja
• Mentor: Milko Jakšić (mentor)
• Mentor: Damir Bosnar (mentor)
• Committee member: Damir Bosnar (predsjednik povjerenstva)
• Committee member: Milko Jakšić (član povjerenstva)
• Committee member: Tomislav Marketin (član povjerenstva)
• Committee member: Denis Sunko (član povjerenstva)
• Committee member: Matko Milin (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Physics); Zagreb
• Defense date and country: 2017-10-05, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract

Detekcija teških iona pomoću emisije sekundarnih elektrona je od iznimne važnosti kod preciznih implantacija teških iona u materiju ili kod proizvodnje nanorupa u raznim polimerima. U ovom radu je napravljen eksperimentalni postav s dva elektronmultiplikatora ispred mete te jednim silicijskim detektorom iza mete. Korištene su četiri mete: zlato, dijamant, mylar i silicij-nitrid. Napravljena je iscrpna kalibracija sustava prije nego što su izmjerene efikasnosti detekcije sekundarnih elektrona za četiri različita snopa: Li+(E=1MeV), H+(E=2MeV) , He3+(E=4MeV) i O+(E=4MeV). Efikasnost ovakvog postava nije dobra za polimere kao što je mylar te keramike kao što je silicij-nitrid. Mjerenja su neprecizna zbog njihove strukture te je broj sekundarnih elektrona po ionu emitiranih iz tih materijala manji nego što je to slučaj kod zlata ili dijamanta. Kod ciljanoga istraživanja jedne mete ova metoda bi bila znatno bolje jer bi se tada mogla postići savršena simetrija. Također je primijećeno da je postav izuzetno osjetljiv na geometriju i simetričnost između dva detektora. Te očekivano je potvrđeno da za veću zaustavnu energiju se emitira više sekundarnih elektrona.

Abstract (english)

Detection of heavy ions by secondary electron emission is of great importance in precise implantation of ions in matter or in nanoholes production in different polymers. In this paper an experimental setup was made with two channeltrons (electron multiplier) in front of the target and one silicon detector behind the target. Four targets were used: gold, diamond, mylar and silicon-nitride. Before the measurements were made the efficiency tests were performed. The efficiency of secondary electron detection was made on four targets with four different blocks: E = 4MeV (E = 1MeV), H+(E = 1MeV) and O+ (E = 4MeV). The efficiency of this setup is not good for polymers such as well as for ceramics such as siliconnitride. The measurements are imprecise due to their structure and the number of secondary electrons emitted per ion impacted on such material is lower than that of gold or diamond. Using one specific target would give significantly better results because perfect symmetry could then be achieved. It is also noticeable that the setting is extremely sensitive to geometry and symmetry between the two detectors. As expected, it was confirmed that greater the stopping power is the number of secondary electrons emitted is greater.

• Keywords: emisija sekundarnih elektrona; zaustavna enenergija; teški ioni; akcelerator; snop; implantacija iona; fotomultiplikator; elektron multiplikator
• Keywords (english): secondary electron emission; stopping power; heavy ions; accelerator; beam; ion implementation; photo-multipliers; channeltron
• Language: croatian
• URN:NBN: urn:nbn:hr:217:235853
• Study programme: Title: Physics; specializations in: Research; Course: Research; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra fizike (magistar/magistra fizike)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2017-10-11 10:33:49