Recent performance and ignition tests of the pulsed SNS H                         -                          source for 1-MW neutron production

Martin P. Stockli; B. X. Han; S. N. Murray; T. R. Pennisi; C. Piller; M. Santana; R. F. Welton

doi:10.1063/1.4916428

Recent performance and ignition tests of the pulsed SNS H ^- source for 1-MW neutron production

Martin P. Stockli, B. X. Han, S. N. Murray, T. R. Pennisi, C. Piller, M. Santana, R. F. Welton

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

8 Scopus citations

Abstract

After acquiring several reliable spare targets, SNS ramped the beam power from 850 kW to 1.4 MW, which required an increase in H ^- beam pulse length from 0.88 to 1.0 ms at 60 Hz. This increase initially produced slow 2-MHz power ramp-ups and, after several weeks of uninterrupted operation, it produced plasma outages every time the pulse length was raised above ∼0.95 ms. Similar outages were previously observed towards the end of long service cycles, which were believed to indicate that the breakdown voltage of the high purity hydrogen started to exceed the induced electric fields. In 2011 the RF was reconfigured to start with 10 cycles of 1.96 MHz, which yielded the shortest H ^- beam rise times and apparently eliminated those plasma outages. The new, pulse-length dependent outages were eliminated by increasing the initial frequency to 1.985 MHz. However, careful frequency studies are unable to justify this frequency. In addition, the paper discusses the issues and solutions for the electron-dump voltage, which starts to sag and become unstable after several weeks of high current operation.

Original language	English
Title of host publication	4th International Symposium on Negative Ions, Beams and Sources, NIBS 2014
Editors	Werner Kraus, Paul McNeely
Publisher	American Institute of Physics Inc.
ISBN (Electronic)	9780735412972
DOIs	https://doi.org/10.1063/1.4916428
State	Published - Apr 8 2015
Externally published	Yes
Event	4th International Symposium on Negative Ions, Beams and Sources, NIBS 2014 - Garching, Germany Duration: Oct 6 2014 → Oct 10 2014

Publication series

Name	AIP Conference Proceedings
Volume	1655
ISSN (Print)	0094-243X
ISSN (Electronic)	1551-7616

Conference

Conference	4th International Symposium on Negative Ions, Beams and Sources, NIBS 2014
Country/Territory	Germany
City	Garching
Period	10/6/14 → 10/10/14

Access to Document

10.1063/1.4916428

Cite this

Stockli, M. P., Han, B. X., Murray, S. N., Pennisi, T. R., Piller, C., Santana, M., & Welton, R. F. (2015). Recent performance and ignition tests of the pulsed SNS H ^- source for 1-MW neutron production In W. Kraus, & P. McNeely (Eds.), 4th International Symposium on Negative Ions, Beams and Sources, NIBS 2014 Article 030001 (AIP Conference Proceedings; Vol. 1655). American Institute of Physics Inc.. https://doi.org/10.1063/1.4916428

Stockli, Martin P. ; Han, B. X. ; Murray, S. N. et al. / Recent performance and ignition tests of the pulsed SNS H ^- source for 1-MW neutron production 4th International Symposium on Negative Ions, Beams and Sources, NIBS 2014. editor / Werner Kraus ; Paul McNeely. American Institute of Physics Inc., 2015. (AIP Conference Proceedings).

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title = " Recent performance and ignition tests of the pulsed SNS H - source for 1-MW neutron production ",

abstract = " After acquiring several reliable spare targets, SNS ramped the beam power from 850 kW to 1.4 MW, which required an increase in H - beam pulse length from 0.88 to 1.0 ms at 60 Hz. This increase initially produced slow 2-MHz power ramp-ups and, after several weeks of uninterrupted operation, it produced plasma outages every time the pulse length was raised above ∼0.95 ms. Similar outages were previously observed towards the end of long service cycles, which were believed to indicate that the breakdown voltage of the high purity hydrogen started to exceed the induced electric fields. In 2011 the RF was reconfigured to start with 10 cycles of 1.96 MHz, which yielded the shortest H - beam rise times and apparently eliminated those plasma outages. The new, pulse-length dependent outages were eliminated by increasing the initial frequency to 1.985 MHz. However, careful frequency studies are unable to justify this frequency. In addition, the paper discusses the issues and solutions for the electron-dump voltage, which starts to sag and become unstable after several weeks of high current operation.",

author = "Stockli, {Martin P.} and Han, {B. X.} and Murray, {S. N.} and Pennisi, {T. R.} and C. Piller and M. Santana and Welton, {R. F.}",

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Stockli, MP, Han, BX, Murray, SN, Pennisi, TR, Piller, C, Santana, M & Welton, RF 2015, Recent performance and ignition tests of the pulsed SNS H ^- source for 1-MW neutron production in W Kraus & P McNeely (eds), 4th International Symposium on Negative Ions, Beams and Sources, NIBS 2014., 030001, AIP Conference Proceedings, vol. 1655, American Institute of Physics Inc., 4th International Symposium on Negative Ions, Beams and Sources, NIBS 2014, Garching, Germany, 10/6/14. https://doi.org/10.1063/1.4916428

Recent performance and ignition tests of the pulsed SNS H ^- source for 1-MW neutron production . / Stockli, Martin P.; Han, B. X.; Murray, S. N. et al.
4th International Symposium on Negative Ions, Beams and Sources, NIBS 2014. ed. / Werner Kraus; Paul McNeely. American Institute of Physics Inc., 2015. 030001 (AIP Conference Proceedings; Vol. 1655).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

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AU - Santana, M.

AU - Welton, R. F.

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N2 - After acquiring several reliable spare targets, SNS ramped the beam power from 850 kW to 1.4 MW, which required an increase in H - beam pulse length from 0.88 to 1.0 ms at 60 Hz. This increase initially produced slow 2-MHz power ramp-ups and, after several weeks of uninterrupted operation, it produced plasma outages every time the pulse length was raised above ∼0.95 ms. Similar outages were previously observed towards the end of long service cycles, which were believed to indicate that the breakdown voltage of the high purity hydrogen started to exceed the induced electric fields. In 2011 the RF was reconfigured to start with 10 cycles of 1.96 MHz, which yielded the shortest H - beam rise times and apparently eliminated those plasma outages. The new, pulse-length dependent outages were eliminated by increasing the initial frequency to 1.985 MHz. However, careful frequency studies are unable to justify this frequency. In addition, the paper discusses the issues and solutions for the electron-dump voltage, which starts to sag and become unstable after several weeks of high current operation.

AB - After acquiring several reliable spare targets, SNS ramped the beam power from 850 kW to 1.4 MW, which required an increase in H - beam pulse length from 0.88 to 1.0 ms at 60 Hz. This increase initially produced slow 2-MHz power ramp-ups and, after several weeks of uninterrupted operation, it produced plasma outages every time the pulse length was raised above ∼0.95 ms. Similar outages were previously observed towards the end of long service cycles, which were believed to indicate that the breakdown voltage of the high purity hydrogen started to exceed the induced electric fields. In 2011 the RF was reconfigured to start with 10 cycles of 1.96 MHz, which yielded the shortest H - beam rise times and apparently eliminated those plasma outages. The new, pulse-length dependent outages were eliminated by increasing the initial frequency to 1.985 MHz. However, careful frequency studies are unable to justify this frequency. In addition, the paper discusses the issues and solutions for the electron-dump voltage, which starts to sag and become unstable after several weeks of high current operation.

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BT - 4th International Symposium on Negative Ions, Beams and Sources, NIBS 2014

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Stockli MP, Han BX, Murray SN, Pennisi TR, Piller C, Santana M et al. Recent performance and ignition tests of the pulsed SNS H ^- source for 1-MW neutron production In Kraus W, McNeely P, editors, 4th International Symposium on Negative Ions, Beams and Sources, NIBS 2014. American Institute of Physics Inc. 2015. 030001. (AIP Conference Proceedings). doi: 10.1063/1.4916428