PAC2013 - List of Authors (Malloch, I.M.)

Paper	Title	Page
WEPAC17	Study on Particulate Retention on Polished Niobium Surfaces after BCP Etching	823
	I.M. Malloch, C. Compton, L. Popielarski FRIB, East Lansing, Michigan, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE SC0000661, the State of Michigan and Michigan State University. Niobium surface defects and inclusions can be introduced during the manufacturing processes used in the production of SRF cavities. Bulk removal methods (sanding, polishing, etc…) are frequently utilized to remove or smooth away these defects on the surface of the niobium metal. It is hypothesized that these mechanical removal methods are capable of trapping performance-degrading particulates, which are then exposed during subsequent chemical processing, potentially contaminating the cavity prior to RF testing. This paper summarizes results of a series of surface roughness and etching experiments performed to determine the relationship between the extent of polishing and trapped particulate, and to determine a method for mitigating this particulate contamination through BCP etching. The relationship between these experiments and RF cavity performance will be explored as well.

WEPAC18	SRF Cavity Etching Developments for FRIB Cavity Processing	826
	K. Elliott NSCL, East Lansing, Michigan, USA I.M. Malloch, L. Popielarski, N. Putnam FRIB, East Lansing, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under cooperative agreement DE-SC0000661. Updates to the FRIB β=0.53 half wave resonator (HWR) design have provided an opportunity to test new buffered chemical polish (BCP) flow control techniques. New processing fixtures have been fabricated and used to process the FRIB β=0.53 HWR. This paper will present details of the fixture mechanical design iterations, the resulting BCP flow simulations, a qualitative evaluation of the agreement between simulations and measured results, and developments in process validation techniques.

Paper

Title

Page

Study on Particulate Retention on Polished Niobium Surfaces after BCP Etching

823

I.M. Malloch, C. Compton, L. Popielarski
FRIB, East Lansing, Michigan, USA

Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE SC0000661, the State of Michigan and Michigan State University.
Niobium surface defects and inclusions can be introduced during the manufacturing processes used in the production of SRF cavities. Bulk removal methods (sanding, polishing, etc…) are frequently utilized to remove or smooth away these defects on the surface of the niobium metal. It is hypothesized that these mechanical removal methods are capable of trapping performance-degrading particulates, which are then exposed during subsequent chemical processing, potentially contaminating the cavity prior to RF testing. This paper summarizes results of a series of surface roughness and etching experiments performed to determine the relationship between the extent of polishing and trapped particulate, and to determine a method for mitigating this particulate contamination through BCP etching. The relationship between these experiments and RF cavity performance will be explored as well.

WEPAC18

SRF Cavity Etching Developments for FRIB Cavity Processing

826

K. Elliott
NSCL, East Lansing, Michigan, USA
I.M. Malloch, L. Popielarski, N. Putnam
FRIB, East Lansing, USA

Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under cooperative agreement DE-SC0000661.
Updates to the FRIB β=0.53 half wave resonator (HWR) design have provided an opportunity to test new buffered chemical polish (BCP) flow control techniques. New processing fixtures have been fabricated and used to process the FRIB β=0.53 HWR. This paper will present details of the fixture mechanical design iterations, the resulting BCP flow simulations, a qualitative evaluation of the agreement between simulations and measured results, and developments in process validation techniques.