Combination of compact nonevaporable getter and small ion pumps for ultrahigh vacuum systems

Abstract

Articles you may be interested inCharacterization of alkali metal dispensers and non-evaporable getter pumps in ultrahigh vacuum systems for cold atomic sensors J. Vac. Sci. Technol. A 30, 061602 (2012); 10.1116/1.4757950 Efficient combining of ion pumps and getter-palladium thin films Description of a dust particle detection system and measurements of particulate contamination from shock, gate valve, and ion pump under ultrahigh vacuum conditions Rev.The rapid pumpdown of ultrahigh vacuum ͑UHV͒ systems, achieved with a very short and low temperature baking or even without baking, is appealing in a variety of research and industrial applications. The use of small volume, compact pumps delivering very high pumping speed is also attractive since it allows minimizing the overall size and weight of the vacuum system, simplifying its design. In the present article, the authors report the results of the pumping experiments carried out on a vacuum chamber pumped by a compact nonevaporable getter ͑NEG͒ pump ͑Capacitorr D 400-2 ® model, SAES Getters SpA, Italy͒ and by a small sputter ion pump ͑SIP͒. To measure the effective contribution of the NEG to the overall pumping, vacuum tests were carried out in a wide range of situations, with/without NEG pump, with/without baking, and changing the pumping speed of the SIP from 60 to 10 l/s ͑N 2 ͒. Significantly lower pressures and faster pumping could be achieved using the NEG pump. Base pressures of low 10 −11 mbar could be obtained in the authors' experimental system with the compact NEG assisted by the 10 l/s SIPs after a 48 h bake-out. The results also show that the system with NEG reached 10 −11 mbar after a very short ͑few hours͒ bake-out. The base pressure was 1 ϫ 10 −10 mbar with 60 l/s SIP alone after a 48 h bake-out, whereas it was 7.9ϫ 10 −11 mbar when combined with the NEG, a better result after only 2 h bake-out. This is quite a remarkable decrease in the bake-out time of a UHV system. It is worthwhile to note that UHV could also be achieved with the NEG even in a fully unbaked system. The pressure of 8 ϫ 10 −9 mbar reached with the SIP alone dropped to 3.9ϫ 10 −10 mbar after adding the NEG. The other interesting result of the NEG-based system is that the pressure increase is much slower when the SIP is switched off. This is also a good characteristic, required for portable vacuum devices, such as UHV suitcases and more generally for systems hosting sensitive materials or components, which can be affected by the pressure increase following a power interruption.

Non evaporable getter (NEG) technology: A powerful tool for UHV-XHV systems

“…In absence of power, the NEG pump mitigates the rate of rise of the pressure in a UHV system (see FIG. 6) [2]. The results shown in figures 4-6 demonstrate that 1) a NEG pump in combination with SIP can boost the vacuum level in the systems, 2) the bake out time can be reduced and 3) the UHV vacuum level is maintained by NEG pump even in case of power failure.…”

“…Ultimate vacuum level of one order of magnitude lower was achieved using the CapaciTorr B 1300 (2x10 -11 vs 2x10 -10 mbar). The benefits of a SIP+NEG combination to get UHV level have been verified in a different vacuum system [2]. In this case, the NEG pump has been activated during the backing process (see FIG.…”

“…NEG pumps have been developed in the 70's and since then they have been widely used by the industry, R&D labs, research centers and large physics projects like accelerators, synchrotrons or fusion reactors. They are used in combination with other pumps, like SIP or TMP [2,3], to improve the final vacuum or reduce the pump down time in a system or to remove contaminants which cannot be pumped by other pumps. They generally operate in the 10 -7 -10 -13 mbar range and present several very unique features:…”

Probe chameleon dark energy with the coupling between a levitated nanodiamond and the single-spin

“…The lower pressure limit of sputter-ion pumps is in the range of 10 −11 mbar. Lower pressures in the range of 10 −12 mbar can only be achieved when the sputter-ion pump works in a combination with other pumping methods [31,32]. In our considerations, a conservative value is taken p = 10 −11 mbar (7.5 × 10 −10 Torr) which is usually required for achieving ultrahigh-Q mechanical oscillators and the ultrasensitive measurements in the levitated optomechanical system [33][34][35].…”

Micromachined 30 K Joule-Thomson cryogenic cooler

“…Hydrocarbons are sorbed only at temperatures around 300 • C. Noble gases cannot be sorbed by this kind of getter. To capture noble gases or hydrocarbons at room temperature, the getter must be used in combination with a second pump, most commonly a sputter-ion pump [106].…”