status of procurements for the arcs instrument doug abernathy arcs hardware project manager arcs...

Status of Procurements for the ARCS Instrument

Doug Abernathy

ARCS Hardware Project Manager

ARCS Construction Project Review DOE Germantown Aug. 9, 2004

SNS Instrument Systems Oak Ridge


ARCS Prototyping Efforts

Based on risks identified early in the project (March 2002 Baseline Review) several efforts were launched:

• Neutronics calculations• Prototyping detectors in vacuum• Testing outgassing of neutron absorbers in vacuum• Single crystal closed-cycle refrigerator• Detector mounting scheme

Total cost of the efforts (approximately):• Hardware $250,000 (vacuum system, detectors, mounting

system, CCR and goniometer, etc.)• Labor $250,000 • About 4% of total project cost• Many components will serve a purpose in the future


Trade off Between Dose and Size for ARCS Beamstop

1 2 3 5


Beam Stop Comparison

• Early study used to determine reasonable sample position for SEQUOIA.• Quantifies size vs. cost for Value Engineering purposes• Case 4 and 5 are for more tungsten

Cost Weight (kg) Diameter (m)

Case 1 $174,464 105,590 3.2

Case 2 $174,464 105,590 3.2

Case 3 $209,745 103,552 3.2

Case 4 $775,898 74,742 2.4

Case 5 $1,094,153 61,529 2.2

Based on Dose Rate Analysis of C. Slater and Engineering analysis of R. Williams

• Updated calculations ongoing, but significant differences are seen due to a re-evaluation of the spectrum from the moderator (E. Iverson)


New material for internal shielding – ZHIP mix

After an extensive search lead by Ralph Niemann, we have found a producer of the B4C + CF2 material:

Dielectric Sciences, Inc.

Chelmsford, Massachusetts

Contacts: Jerry Goldlust, Steve Rigby

They have dubbed this “Zero Hydrogen In Product mix”

ARCS has contracted with them to supply samples and design studies for our needs. They are affiliated with an ISIS supplier for crispy mix and will bid on supplying material to the MERLIN instrument.


ZHIP mix properties vs. crispy mix

•Binder typically 6% by weight (DSI says best workability)

•Good mechanical properties, low shedding of grit

•Easily put on Al backing

•Procedures worked out to get high density (1.9 gm/cm3)

•Outgassing performance excellent compared to epoxy based mixture

•Neutronic performance comparable to standard crispy mix


Outgassing measurements

•Used ARCS large test vessel

•Procedure (Rate-of-rise test)

•Load sample

•Pump; T=0 when P<1mTorr

•At desired time, note pressure and close gate valve

•Wait dt ~ 15s

•Note pressure

•Open gate valve

•Calculate dP/dt and qA


Rate-of-rise

1.00E-07

1.00E-06

1.00E-05

1.00E-04

0.1 1 10 100

Time (hours)

dP/d

t (

Tor

r/s)

DMTC-6 B4C 12% epoxy - Essex X-rayDMTC-7 B4C 3% epoxy - Essex X-rayDMTC-9 New holder; no sampleDMTC-10 B4C 5% epoxy Essex X-ray (2nd time)DMTC-12 Holder; no sampleChamber dP/dtDMTC-19 B4C 5% non-HDMTC-20 B4C 5% non-H 2nd timeChamber dP/dt 2


Outgassing - background subtracted

1.00E-08

1.00E-07

1.00E-06

1.00E-05

1.00E-04

0.1 1 10 100Time (hours)

q_A

(T

orr.

l/s/c

m2)

MAPS crispy mix data

DMTC-6 B4C 12% epoxy - Essex X-ray

DMTC-7 B4C 3% epoxy - Essex X-ray

DMTC-10 B4C 5% epoxy Essex X-ray (2nd time)

Crispy Mix Model

DMTC-19 B4C 5% non-H

DMTC-20 B4C 5% non-H 2nd time


Crispy mix scattering

1

10

100

1000

1 10 100 1000Energy (meV)

90 d

egre

e d

etec

tor

(cts

/1e6

mo

n)

Epoxy 5% flat

Epoxy 5% bumpy

non-H 5% flat

non-H 5% bumpy


ARCS Procurement Status Overview

Item Design Procurement Cost

Core Vessel Insert Done At SNS $92,400

Shutter Insert Done In manufacturing $59,610

Guide – shutter Done Expected 11/04 $60,000

Guide – beamline Draft spec ~1 year delivery $260,000

Guide – end Conceptual $30,000

T0 chopper Draft spec ~ 9 month delivery $261,000

Fermi chopper Done Expected 2/05 $410,000

Slit Package Assembly Under testing ~12/05 $40,000

LPSDs Done Expected 10/04 $1,100,000

Electronics & Mounting Final testing As needed $600,000

Vacuum chamber – sample isolation, vessels & pumps

Draft spec; Pre-bid meeting 6/04

Contract ~10/04

~1 year delivery

$1,200,000

Shielding – Poured-in-place Done SNS organized $30,000

Shielding - Other Neutronic evaluation ongoing

$1,000,000

Green: Committed $

Blue: Expected by 10/04


Early Procurements Driven by Target Schedule

• Core vessel and shutter insert components procured through common SNS effort – deliveries and testing on schedule

• Need for shutter guide and housing by Nov. 2004 prompted a division of the guide procurement into different sections– Shutter guide specified and procurement awarded to CILAS;

design review complete; production started– Beamline guide specification drafted; expect award in Sept.

2004 with delivery ~1 year later– Guide end between Fermi chopper and sample is dependent on

details of sample area design, performance gains depend on sample size and tolerance for divergence

• Shutter guide is an example of value engineering – m=2.5 chosen compared to nominal m=3.6 original design


Guide gain varying shutter guide coating

0.00

2.00

4.00

6.00

8.00

10.00

12.00

10.00 100.00 1000.00

Energy (meV)

Gai

n

m=0 shutter guide

m=2.0 shutter guide

m=2.5 shutter guide

m=3.0 shutter guide

m=3.6 shutter guide


Percentage loss varying shutter guide coating

1 - Gain(m)/Gain(3.6)

0.00

0.05

0.10

0.15

0.20

0.25

0.00 200.00 400.00 600.00 800.00 1000.00

Energy (meV)

0.00

2.00

2.50

3.00


Fermi Chopper

• SKF/Revolve chosen as supplier – other possible vendors are based in Europe and posed risks to efficient coordinated design

• Building on SNS prototyping experience, the slit package assembly will be designed and built by ARCS in collaboration with the SNS Chopper Group while the magnetic bearing specialists provide proven bearing and phase control plus housing and service connection

• Contract includes integrated testing of 3 chopper systems plus one additional rotor using the translation table that will allow for quick changes of resolution in operations

• Current slit package assembly activities– Evaluation of possible absorbing slat materials complete – 10B

coated, 0.35mm thick material most absorbing but a less expensive boron-fiber composite may be adequate for lower energies

– Final FEA analysis underway– Assembly jig and test pieces being constructed at ANL (R. Niemann)– Spin test contract in place to validate design for final production

• Delivery of systems foreseen for early 2005 (not a time critical activity)


Considerations for the ARCS first chopper area

• Purpose: Reduce background at detectors by blocking beam when protons hit the target– Eliminate unwanted neutrons both before

and after desired incident energy

• Two types currently used as spallation sources– Horizontal axis (ISIS & Lujan): 30 cm

Inconel– Vertical axis (IPNS): ~inches Be

• Engineering study done to see feasibility of producing fast (>=120 Hz) choppers of both designs– Magnetic bearings for speed and reliability– Use FEA to guide design


Vertical Axis T0 chopper scientific design

• Typical parameters– Channel width min. 8 cm– Channel width max. 10 cm– Radius 25 cm– Rotor weight ~800 lbs.

• Operation at 30 Hz intervals– Max. to be determined by

detailed engineering ~120 Hz

• Open questions– How much material really is

needed in the beam at T0?– Can crystal alignment be done

with chopper operating?

-300

-200

-100

0

100

200

300

-300 -200 -100 0 100 200 300


Nominal Open Area

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

0.00 1000.00 2000.00 3000.00 4000.00 5000.00Time (us)

Horz. Axis

Vert. Axis

Geometric beam blockage for T0 choppers - Time

• Operating at 120 Hz with minimum of 30cm of Inconel in beam at T0 and phased for 1000 meV (vert. axis)


Geometric beam blockage for T0 choppers - Energy

• Horizontal axis: wide bandpass with high energy leakage

• Vertical axis: beam blocked outside of incident energy

Nominal Open Area

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

10.00 100.00 1000.00 10000.00 100000.00

Energy (meV)

Horz. Axis

Vert. Axis


Detectors

• Reuter-Stokes chosen from 2 bidders to supply LPSDs – low risk based on existing instruments world-wide

• Cost is reduced by using SNS (DOE) supplied He-3 roughly 20%. This represents a contribution by SNS to the IDT budget.

• First 8 detectors received at SNS at the end of July. Once performance is confirmed remaining tubes will be manufactured by end of October.

• Placement of this order (probably 2nd largest single contract) represents a large reduction in risk to the project.

• Electronics and basic hardware for 8-pack detector modules are proven – a final iteration on the design will be built to test for problems before production

• Evaluation of the frame to hold detectors within the vacuum vessel is ongoing using a mock-up at ANL

• There will be a smaller order (~16 tubes) for special detectors around the beam exit – design to be completed


Design goals for the ARCS vacuum vessel

• Use SNS standard mounting flange for sample environment equipment; accommodate sample motion esp. rotation

• Provide cryogenic vacuum for sample with quick (< 1 hr) changeout and good access for special equipment

• Minimize/eliminate neutron windows (thin Al), particularly near sample• Mount and provide access to neutron detectors ( turnaround ~ several

hours)• Accept additional components – variable aperture, oscillating radial

collimator• Include internal neutron shielding (“crispy mix”)• Allow for external neutron shielding to block background• Non-magnetic material ~2m around sample• Simple, turnkey operation of overall system


ARCS vacuum vessel procurement status

Strategy: Look for a single vendor to produce a turnkey system, unless there is added value for separating sample and detector areas. Sample isolation area and detector area specifications to be sent together to interested parties.

• A vendor pre-bid meeting was held at SNS June 29, 2004.– Distributed preliminary specifications– General goals as well as some engineering constraints were presented– Tour of the target building and ARCS beamline area

• Total of ~10 vendors attended or requested to receive the final request-for-proposals

• Discussion with one manufacturer indicates the gate valve concept is feasible, could be integrated into a sample vessel and tested separately

• Sample isolation is an important value engineering concept – cost recover for one hour of SNS beamtime would be >$30,000


Shielding

Much of the shielding work has been waiting for more feedback from neutronic calculations for both dose rate (0.25mrem/hr) and background

• Initial SNS shielding studies performed by an external ORNL computational group– Not necessary in tune with common practices in neutron scattering

instrument– Little added institutional learning– Source file used was common to all instruments and overestimated high

energies

• Decision taken for this effort to move to an SNS computational group– Group is shared with target – some delays while important issues were

addressed– Recently many beamlines are getting a second look with a more realistic

source – particularly advantageous for ARCS in near backscattering from target


Personnel issues

Additional effort will need to be “procured” for ARCS to meet its schedule goals

• Argonne effort will end with FY04– Core instrument team at ORNL (scientist & engineer) now– Ramp up of intensive designer work makes long distance coordination

more difficult– More detailed interaction with SNS shared activities and target related

installations– Ralph Niemann will retire

• A statement-of-work for a designer is drafted• Discussions for engineer time to replace R. Niemann’s efforts

coordinating chopper activities for ARCS underway

status of procurements for the arcs instrument doug abernathy arcs hardware project manager arcs...

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