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Properties of Laser Ablation Products of Delrin with CO<sub>2</sub> Laser

Eckel, Hans-Albert und Schall, Wolfgang und Tegel, Jochen und Waiblinger, Frank und Walther, Sebastian (2004) Properties of Laser Ablation Products of Delrin with CO<sub>2</sub> Laser. Projektbericht. A849824, 79 S.

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Offizielle URL: http://www.stormingmedia.us/84/8498/A849824.html

Kurzfassung

A requirement for efficient pulsed laser propulsion from ground to LEO is the achievement of a specific impulse of up to 800's at a jet efficiency of at least 50%. With classical polymers like Delrin or POM these numbers cannot be obtained. The suggestion to use polymers with included metal powder for a better deposition of the laser energy per unit volume and thus the achievement of a higher jet velocity together with a lower ablation rate has been experimentally investigated. Samples of different polymers and different metal contents (Al and Mg in the range of 3% to 60% by weight) have been formulated and irradiated with CO(sub 2) laser pulses of about 12 microseconds in duration and energies of 40 J to 280 J (fluences of 20 to 150 J/sq cm). The samples were mounted to a pendulum for measuring the excerted impulse and the mass loss per pulse was determined by weighing. These experiments have been carried out in ambient atmosphere as well as at various pressure levels down to vacuum of less than 1 mbar in a vessel. In general the expansion of the ablated material (vapor) was forced to be one-dimensional by applying a guiding tube. But three- dimensional expansions were investigated as well. Furthermore the efficacy of certain selected formulations as a propellant have been tested in a bell shaped light concentrating structure. The samples have been inspected under an electron microscope before and after the laser interaction. Because a suspicion existed from the beginning of the experiments that a certain amount of the incident laser energy might be absorbed in a decoupled plasma wave (breakdown) time resolved power measurements of the incident enemy of the reflected energy from the target and at a later stage of the energy transmitted through a hole in the target were made.

Dokumentart:Berichtsreihe (Projektbericht)
Titel:Properties of Laser Ablation Products of Delrin with CO<sub>2</sub> Laser
Autoren:
AutorenInstitution oder E-Mail-Adresse der Autoren
Eckel, Hans-AlbertNICHT SPEZIFIZIERT
Schall, WolfgangNICHT SPEZIFIZIERT
Tegel, JochenNICHT SPEZIFIZIERT
Waiblinger, FrankNICHT SPEZIFIZIERT
Walther, SebastianNICHT SPEZIFIZIERT
Datum:Juli 2004
Erschienen in:Storming Media Pentagon Reports
Referierte Publikation:Nein
In SCOPUS:Nein
In ISI Web of Science:Nein
Seitenanzahl:79
Status:veröffentlicht
Stichwörter:ABLATIVE MATERIALS, ALDEHYDE POLYMERS, CARBON DIOXIDE LASERS, DELRIN, DEPOSITION, DOPING, ENERGY CONVERSION, GASES, LASER APPLICATIONS, PULSED LASERS, SOLIDS, THREE DIMENSIONAL, VACUUM
HGF - Forschungsbereich:Verkehr und Weltraum (alt)
HGF - Programm:Luftfahrt
HGF - Programmthema:Starrflügler
DLR - Schwerpunkt:Luftfahrt
DLR - Forschungsgebiet:L AR - Starrflüglerforschung
DLR - Teilgebiet (Projekt, Vorhaben):L - Laserforschung und -technologie
Standort: Stuttgart
Institute & Einrichtungen:Institut für Technische Physik
Hinterlegt von: Dr.rer.nat. Hans-Albert Eckel
Hinterlegt am:30 Mär 2006
Letzte Änderung:27 Apr 2009 05:05

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