_______________________________________________________________________

Project Components

Below are the major project components, the person taking primary responsibility for each, and the currently estimated cost. At the bottom is also an estimate of the funds not yet directed.

Beamline X21:

Chi-Chang says that work to install a new mirror (upwardly reflecting) and new monochromator tank will be finished by Summer 2002. The monochromator tank may allow rapid switching between multilayer and silicon resolution. We need to discuss this further with Chi-Chang. The NSLS Scientific Advisory Committee (SAC) was scheduled to meet in November, but that meeting has been postponed. We should be prepared to present a brief report on our research program and chamber development when the SAC does meet.

Hutch (Karl):

We will need to share the X21 hutch with a small-angle x-ray scattering (SAXS) setup going in behind our position. The dimensions of the SAXS setup have not yet been determined. After the new mirror is installed, the x-ray beam will enter the hutch approximately 44” from the left wall and 60” above the floor. The hutch is approximately 15’x15’ with a 77” wide door at the back. The door begins 3’ from the right hand wall of the hutch.

Table (Karl): $7 k

Chi-Chang has offered us the use of an existing x-y-z table that is designed to be used with his diffractometer. Tony Lenhard, the NSLS technician with the drawings of the table was unavailable for help when Karl recently visited NSLS because staff was preparing for an upcoming visit from Hilary Clinton. Hopefully we’ll get the drawings soon. Karl has rough table dimensions. Photographs are here and here.

The only significant problem with the table appears to be that the z-motion actuator can’t handle the necessary weight. Karl estimates that the total weight of the diffractometer and chamber will be approximately 3500 lb. The current z-actuators (there are three of them) are Duff-Norton Model TKM 2500-3-1. Their Product Code is MCBBBCOD0033. A pdf file of the current Duff-Norton catalog is here. Karl is contacting Duff-Norton about beafier models.

The bottom of the existing z-actuators have ball feet. Karl assumes that these were used to center the table on mating pads in the concrete floor. However, he didn’t notice such mating pads in the existing floor (although the hutch is currently very crowded because it is being used for storage). Chi-Chang thinks that the pads are indeed there….

Chi-Chang suggested that we might want to put the table on a rail track to move it in and out of the beam (thus allowing the SAXS setup to get the beam). Currently the table has three wheels that can be moved down into position. Karl prefers the idea of wheeling the table so that it can be easily removed from the hutch completely. He needs to check whether the current wheels can handle the weight.

Diffractometer (Karl): $5 k

Chi-Chang Kao has offered us the use of existing Franke goniometers at X21. The goniometers include:

-- “Small” Franke goniometer 91050A

(Motor: Berger RDM 5913/50 I_w=2.8 A, R_w = 1 W)

-- 2 “Large” Franke goniometers 91051A

(Motors: Berger RDM 51117/50 LNB I_w=5 A, R_w = 0.3 W)

-- Pair of ± 20° Franke Tilt Stages 91037B

(Motors: Superior Electric MO91-FD09)

Chi-Chang has now forwarded a number of files with dimensions of the table and diffractometer supporting pieces. Karl is still figuring out what it all means.

Current versions of the goniometers are displayed in the Franke catalog here. Current versions of the tilt stages are displayed in the Franke catalog here. Photographs of the goniometers are here and here.

Currently the goniometers are configured to function in a standard Eulerian 4-circle mode (an almost identical set is installed on beamline X22 – Doon Gibbs’ beamline (a poor photograph of Doon’s diffractometer taken through the hutch window is here)). This is rather different than the geometry that we’re proposing to use for the surface scattering chamber. Karl sees no reason to change our original plans – Chi-Chang says that we can use the goniometers in any geometry we want. Chi-Chang is also offering us the use of a vertical mount to hold the Franke goniometers. In our geometry, we would need the vertical mount to hold only the 2-theta arm. Chi-Chang also has a very large 2-theta arm for the diffractometer (it was originally intended for a horizontal scattering geometry). He says that we can cut it down to make it a more reasonable length.

Diffractometer Control Electronics and Detectors (Karl): $15 k

Chi-Chang says that NSLS is currently thinking of using the EPICS software package on X21. This is in contrast to most of the NSLS beamlines which use SPEC. EPICS was developed at the APS/Argonne and Los Alamos. It has the advantage that it can work in a very distributed manner so that the entire set of beamline motors could be controlled either from a computer at the X21 back hutch or by a computer at the X21 front hutch, i.e. control could be easily moved back and forth. A disadvantage is that there is little support for Epics at NSLS and it has apparently developed the reputation of requiring considerable dedicated support at the APS. An overview of EPICS is here. The Certified Scientific webpage describing SPEC is here. Detailed consideration of motor controllers is awaiting resolution of this issue. Detectors have not yet been discussed.

UHV Chamber (Randy, Karl): $20 k

Randy’s design for the chamber is here. Advanced Design Consulting Corp. in Ithaca (adc@advdes.com) is building a similar design for Cornell for $6500. Lesker has quoted $20,750. Sharon Vacuum has quoted $8,950 and MDC has quoted $9,925. The Boston University Scientific Instrumentation Facility (BU-SIF) has given us a quote of $8-10k with a turnaround time of approximately 2 months. We have tentatively decided to go with the BU-SIF.

In addition to the new chamber, we are considering changes to Randy’s existing chamber so that we will have separate chambers for MBE growth and for plasma processing.

The chamber’s beryllium windows are mounted on MDC flanges. These flanges are no longer listed in the MDC catalog. Their specs are here. Karl is contacting Electrofusion and for quotes. Since windows will be cheaper per piece when purchasing more than one, Karl will request the quotes for 3 windows so that we’ll have one spare. He’ll also investigate costs of having these companies braze the beryllium on the flange versus having a third party (e.g. Advanced Design Consulting Corp.) do the brazing.

Sample Manipulator with Zeta and Theta Motions (Chip): $20 k

This is going to be a difficult part of the project, since it is integrated with the rotational zeta and theta motions. The sample holder will use a borelectric heater and will have to be RF biasable. It would also be nice if we could include some tilt arcs for better sample alignment, but that may be difficult. Due to the corrosive Cl gas, we should try to keep all motors outside the vacuum.

Randy had used a custom design from Thermionics. He thinks that they would be happy to make another one, but that iterating on the design process could be rather slow.

Load-lock Chamber, Transfer System, Pump, Gauges (Chip): $12 k

We’re considering the MDC 665085 load-lock system.

Effusion Cells (2) (Ted): $53 k

Ted has a quote for effusion cells from Applied Epi. This quote includes two effusion cells, the necessary four cell controllers/power modules, a nitrogen gas purifier and two crucibles. With the current chamber design, they must attach to a 4 ½ “ flange (which these cells do). They will be water-cooled. If these systems are to be in the chamber when Cl gas is used, then they must be shuttered, which is not included in the current quote.

Plasma Source for MBE (Ted): $34 k

Ted has a quote for a UNI-Bulb RF plasma source from Applied Epi. The quote includes plasma source, manual tuning unit, power supply w/controller and variable leak valve. It must attach to an 8” flange or smaller (apparently this configuration attaches to 4.5” flange).

Plasma Source for Surface Processing (Chip): $32 k

Chip has a quote that he likes from Specs USA Inc. The source must attach to an 8” flange.

Sample Bias Power Supply (Chip): $7 k

Chip is pricing a power supply from Advanced Energy Industries – the RFX 600.

RHEED System (Ted): $20 k

Ted is pricing systems from Creekside Technologies and other companies. He has an initial quote of $39k from Applied Epi, but this seems quite high. With the current chamber design, the electron gun must attach to a 2 ¾ “ flange and the screen must attach to a 6” flange. We must also check for proper distance to the focal point. If this system is to be in the chamber when Cl gas is used, then it must be shuttered.

Turbo Pump and Vacuum Gauges (Chip): $25 k

Randy’s current chamber has a 450 l/sec pump. We were considering a 700-1000 l/sec pump. Chip currently has a quote from Steve Harvell for $20.3k for a corrosion-resistant TMP1000C 1000 l/sec turbo and D40BCS rotary vane backing pump (no gauging). While we have considered a dry backing pump, quotes for a turbo with a dry backing pump are approximately $40k. This is more than we have available.

Gas Handling System (Chip): $13 k

We will need the capability of handling 10 sccm of Cl₂ gas and 1 sccm of H₂ gas. There is currently no gas handling at X21. Chi-Chang says that we may or may not need to help pay for installation of venting there depending upon cost.

UNCOMMITTED FUNDS: $31 k