tevatron beam separator r@d

O.Prokofiev E&F meeting, Nov.15, 2005 1

Tevatron Beam Separator R@D

• Overview

• Activities at MP-9 since Feb 2004

– Construction of polarity switches

– Assembly of HV power supplies (180kV and 250 kV)

– Construction of separator production facility (clean room, test cave,…)

– Separator assembly

– Conditioning at higher voltages

– Electrode material R&D

• Plans for 2006

People Involved:AD

R. Moore, D. Bollinger, B. Hanna, J. Johnstone, R. Meadowcroft, S. McCormick, T. Sen, V.Shiltsev, J. Walton

TDP. Limon, L. Alsip, R. Bossert, M. Chlebek, D.Conolly, L.Elementi, G. Kobliska, A.Makarov, O. Prokofiev, G. Smith, D.Sorensen, J. Wittenkeller, J. Zweibohmer,


TeV Separator Spark history

Electrostatic separators used to put p-bars and protons on different orbits (“helices) to avoid beam interactions. 24 separators grouped into 13 stations around of ring.

Fermi news:… Tev separator sparked and kicked out the last bunch…… C17 separator started sparking…… TeV vertical separator sparked 3 times……. store 4078 quenched due to separator spark……. separator sparks caused loss of luminosity and then…

Electrode length – 101.25”Electrode gap – 50 mm Maximum voltages – up to 120 kV / plate)

0

1

2

3

4

5

6

7

8

12/20/02 4/19/03 8/17/03 12/15/03 4/13/04 8/11/04 12/9/04 4/8/05 8/6/05 12/4/05

Tota

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B11H-1(105 kV) B11V-1 (110 kV) D11H-1 (106 kV)C17V-1 (120 kV) C17V-4 (120 kV) B17H-2 (120 kV)B17H-3 (120 kV) B17H-4 (115-120 kV) A49V-1 (110 kV)C49V-1 (95-103 kV) A49V-2 (95-110 kV)

Operational losses due to separator sparksin 2004-2005 are about 2 weeks (~10k$/hr).


Separator R&D Program

• Motivating Higher Voltage Operation Separation on ramp limited by voltage

Can B17H, C17V run @ 150 kV for few min with acceptable spark rate?

During HEP stores, IP separators run at ~100kV

Running @ 120 kV seems to be a realistic goal 20% more voltage ⇒ 20% more separation

Can IP separators run @ 120 kV for many hours with acceptable spark rate?

• Conditioning at higher voltages

Conditioned up to 150 kV during original productionNow conditioning spare separators at up to 180 kVObtaining nice data on spark rate vs voltage

• Try new electrode material

Test separator reassembled with electropolished stainless steel electrodesAssembly separator with Ti electrodes

• Goals

Improve separator performance and reliability Reach 1 spark/year at voltages 150 kV per plate (6.0 MV/m)


Conditioning Test Facility at MP-9

New factory was constructed at MP- 9 for separator production.Facility include a clean room class 10000, baking oven, conditioning cave, automatic setup for radiation scan and measuring system.


Automatic Measurement Setup

Measuring scheme

Automatic setup was developed and constructedby D.Conolly and L.Elementi.

Measured parameters:- polarity- voltages, currents, sparks- pressure, temperature- radiation, hot spot position


Conditioning Procedure

The high voltage was applied on 2 electrodes with following combination:

(-150kV, 0), (0, +150kV) change polarity (0, -150kV), (+150kV, 0) (-150kV, +150kV) change polarity (+150kV, -150kV) (-170kV, +170kV) change polarity (+170kV, -170kV) (-180kV, +180kV) change polarity (+180kV, -180kV)

(-150kV, 0), (0, +150kV) change polarity (0, -150kV), (+150kV, 0)

PositivePolarity

NegativePolarity

# 27


Conditioning at 150 kV (July 13, 2005)

~ 1 hour

Positive Polarity

~ 1 hour

Negative Polarity

0

30

60

90

120

150

180

9:36 9:50 10:04 10:19 10:33 10:48 11:02 11:16

Volta

ge, k

V

Minus Plus

-30

0

30

60

90

120

9:36 9:50 10:04 10:19 10:33 10:48 11:02 11:16

Curre

nt, µ

A

0

10

20

30

40

50

9:36 9:50 10:04 10:19 10:33 10:48 11:02 11:16

Tota

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rks

1.E-09

1.E-08

1.E-07

1.E-06

9:36 9:50 10:04 10:19 10:33 10:48 11:02 11:16

Pres

sure

, tor

r

~25 sparks

0

30

60

90

120

150

180

11:19 11:22 11:25 11:28 11:31 11:34 11:36

Volya

ge, k

V

Minus Plus

-30

0

30

60

90

120

11:19 11:22 11:25 11:28 11:31 11:34 11:36

Curre

nt, µ

A

0

2

4

6

8

10

11:19 11:22 11:25 11:28 11:31 11:34 11:36To

tal n

umbe

r of s

park

s

1.E-10

1.E-09

1.E-08

1.E-07

11:19 11:22 11:25 11:28 11:31 11:34 11:36

Pres

sure

, tor

r

3 sparks

# 27 # 27


Conditioning (Negative Polarity) at 150 - 180 kV (July 13, 2005)

Cable breakdown

0

40

80

120

160

200

11:31 12:00 12:28 12:57 13:26 13:55 14:24 14:52

Volya

ge, k

V

Minus Plus

-30

0

30

60

90

120

11:31 12:00 12:28 12:57 13:26 13:55 14:24 14:52

Curre

nt, µ

A

0

100

200

300

400

500

11:31 12:00 12:28 12:57 13:26 13:55 14:24 14:52

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1E-09

1E-08

1E-07

1E-06

1E-05

11:31 12:00 12:28 12:57 13:26 13:55 14:24 14:52

Pres

sure

, mba

r

Cable breakdown

Negative Polarity

~ 3 hours

Cable sparks

~ 50 sparks

# 27

Conditioning separators at up to 180 kV:- conditioning much more quickly (hours vs days)…- …at a cost – damaged HV cables, 1 MOhm shunt,

control unit, HV power supply, a polarity switch….

Burning fiberglass

Dirty F- 77


From [email protected] Wed Oct 13 16:18:50 2004Date: Wed, 13 Oct 2004 15:18:44 -0500From: Romesh Sood <[email protected]>To: Bob Kephart <[email protected]>, Yarba Victor <[email protected]>Cc: Limon Peter <[email protected]>, Prokofiev Oleg <[email protected]>, Romesh Sood <[email protected]>, Apollinari Giorgio <[email protected]>Subject: Phase- I ORC Recommendations For The MP9 Electronics Beam Separator Conditioning & Test Setup

Dear Bob, Victor,

The MP9 Electronics Beam Separator Conditioning & Test Setup is now ready to commence *Phase-1* full operation (_*Phase-1 with no power onaccess*_).* *In addition to a comprehensive written Hazard Analysis, the TD-Support Department conducted a thorough safety analysis of all potential hazards listed below:

Electrical - High Voltage Power Supply,Ionization Radiation,Mechanical Safety, andChemical Safety

We also reviewed, identified, and assisted the MP9 user group in qualifications, personnel training requirements, and emergency preparedness. I am pleased to inform you that all electrical safety items, including proper grounding of the equipment, have been accomplished. Working with Oleg Prokofiev, a comprehensive LOTO procedure has been developed. This afternoon Jim Garvey has trained four TD-E&F employees (Oleg Prokofiev, Glenn Smith, Roger Rojo Jr., and Mark Chlebek) to carryout these procedures safely.

The Ionization Radiation; An x-ray radiation exposure is a real concern. Therefore my recommendation is to grant a limited _*Phase-1 ORC*_, i.e., exclude a power-on-access into the cave enclosure until a positive control over the run-away power supply and high voltage threshold is established.

SincerelyRomesh Sood

Beam Separator Test Facility at MP-9

Hazard Analysis

Prepared by: Peter Limon Project Manager

and Oleg Prokofiev

September 30, 2004

Sept. 20, 2004

Technical Division

Beam Separator Test Facility

Standard Operating Procedure

for Separator Conditioning Test at MP-9

f

Fermi National Accelerator Laboratory Batavia, IL 60510

TEVATRON BEAM SEPARATOR

HIGH VOLTAGE CONDITIONING TESTING

TRAVELER

Reference Drawing(s)

Tevatron Beam Separator Final Assembly 2214-ME261545 Hor izontal

2214-ME261546 Ver tical

Project# / Task #: Job #: Released by: Magnet/Device Ser ies: Date: Scan Pages: Prepared by: B. Jensen, O.Prokofiev

Title Signature Date TD / E&F Process Engineer ing

Bob Jensen/Designee

TD / E&F Assembly

Glenn Smith/Designee

TD / E&F Project Physicist Oleg Prokofiev/Designee

TD / E&F Project Physicists

Peter Limon/Designee

Safety, Procedures, Travelers, Instructions

TECHNICAL DIVISION ENGINEERING AND FABRICATION GROUP

LOCK OUT/TAG OUT PROCEDURE

re Number: TD-512045

Document EFG-Elec-

Revision Number & Date:

by (Knowledgeable person) kofiev Date: 9/28/04

Organization TD EFG

Extension 6636

by: arvey Date:

Organization TD Support

Extension 4160

by: Kephart Date:

Organization TD HDQ

Extension

t identification/description tatic Beam Separator MP-9 Test Facility

: pose of this procedure is to identify the specific hazardous energy sources associated with this

ent and the methods used to lock and tag them out to allow safe servicing. This procedure is an entation of Fermilab ES&H Manual, Chapter 5120, and titled Control of Hazardous Energy for Personnel Safety.

GENERAL INFORMATION Scope: These procedures cover the Lockout/Tagout steps that are to be performed on the Glassman High Voltage Power Supplies and control system of Electrostatic Beam Separator MP-9 Test Facility before inserting, removing, moving, or otherwise handling exposed ends of the high voltage cables in the test cave used to supply power to the Beam Separators, and to restore the system following this work to an operational ready condition. Special Concern: This LOTO action is required before changing out beam separator assemblies, removal or re-connection of the high voltage cables, or other maintenance work where there is an exposure to the employee from the high voltage power supplies. Qualification of Workers: Authorized Individuals LOTO Level II training is a pre-requisite to performing this procedure. Workers who are annually certified in this written procedure will be classified as “Authorized Individuals” in this document. A list of qualified individuals will be posted at the location of the LOTO keylock box. High Voltage Knowledgeable Persons Only personnel who have the knowledge and experience to work on high voltage power supplies are to be classified as a “high voltage ps knowledgeable person” capable of trouble shooting the system.


Automatic Setup for Radiation Scan

Linear driver

Detector

The automatic scan significantly simplified the radiation scan procedure and improved a safety environment at MP-9. In the previous conditioning facilities to do X-ray scan the interlocks to the cave must be bypassed and a minimum of 3 people were needed for radiation survey (one person is outside of cave and adjusts voltages, the other two people are separator expert who will perform the scan and Radiation Safety person to monitor a situation).

Radiation Scan (100 µA, 95 kV)

0

100

200

300

400

500

600

20 40 60 80 100 120 140 160

Distance, inch

Radi

atio

n Do

se, m

R/hr

~ 15" from separator

~ 3" from separator

104”

Hot spot


Separator Opening and Cleaning (July 12, 2005)

Metal chip

Found silver plated metal chip ~ ¼” long


Results of Conditioning Tests

A list of Separators conditioned at MP-9

# 28, horizontal, hand-polish SS (Jan - Feb, 2005)

# 6, vertical, electro-polish SS (Apr - Jun, 2005)

# 27, vertical, electro-polish SS (Jul – 05)

# 4, horizontal, hand-polish SS (Jul – 05)

# 8, vertical, electro-polish SS (Aug-Nov, 2005)

# 29, hand polish titanium electrodes under construction


Electropolishing Process Verses Mechanical Polishing

ElectropolishMechanical polish

Roughness: 4 - 40 microinches(depends from abrasive grit number)

Roughness: 2 - 5 microinches

Electropolishing (used since early 1950’s) is the electrochemical removal of microscopic irregularities or diminution scratches, burns and unwanted harp edges from metal surfaces. Typical material removal is .0001”- .0004” per surface.

Mechanical polishing is an operation designed to prepare a metal surface for electropolishing or to satisfy non-critical surface roughness requirements. Mechanical polishing reduces all surface ridges, microprotrusions, pits and discrepancies to provide a homogeneous appearance and roughness.

Smoothness of the metal surface is one of the primary and most advantageous effects of electropolishing.

Electropolishing should improve separator performance.


Conditioning at 150 kV: Spark Rate for # 6 and # 8

Spark Rate at 150 kV #6 (electro-polished) : 0.25 +/- 0.15 per day #8 (hand-polished) : 1.2 +/- 0.3 per day

1

10

100

4/6 4/8 4/10 4/12 4/14 4/16 4/18 4/20

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Minus Plus

End of measurements

Spark rate: 0.3 +/-0.2 sparks per day

PositivePolarity

1

10

100

4/18 4/20 4/22 4/24 4/26 4/28 4/30

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rks Minus Plus

End of measurements

Spark rate: 0.2 +/-0.14 sparks per day

Negative Polarity

Electro-polished electrodes

Separator # 8Spark rate at 150 kV (Negative polarity)

0.1

1

10

100

3/3 3/4 3/5 3/6 3/7 3/8 3/9 3/10

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1.2 +/- 0.4 sparks per 24 hours

Separator # 8Spark rate at 150 kV (Positive polarity)

0.1

1

10

100

3/9 3/10 3/11 3/12 3/13 3/14 3/15 3/16

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1.2 +/- 0.5 sparks per 24 hours

Hand-polished electrodes


1

10

100

7/15 7/17 7/19 7/21 7/23 7/25

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Minus Plus

Spark rate at 180 kV: 1.2 +/-0.5 sparks/day

Positive polarity

#27

Spark RateEstimation

End of measurements

1

10

100

7/23 7/25 7/27 7/29 7/31 8/2

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Minus Plus

Spark rate at 180 kV: 0.9 +/- 0.4 sparks/day

Negative polarity

#27

Spark RateEstimation

End of measurements


1

10

100

6/18 6/19 6/20 6/21 6/22 6/23

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Minus PlusEnd of

measuremet


Positive polarity

1

10

100

6/22 6/23 6/24 6/25 6/26 6/27 6/28

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End of measureme

t


Negative polarity

Electro-polished electrodes Hand-polished electrodes

Spark Rate at 180 kV # 27 (electro-polished) : 1.0 +/- 0.3 per day # 4 (hand-polished) : 1.45 +/- 0.35 per day



Conditioning at 175 kV (Negative/Positive Polarity)

1

10

100

1/30 1/31 2/1 2/2 2/3 2/4 2/5 2/6 2/7 2/8

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Minus Plus

Positive Polarity0.5 +/- 0.4 spark per 24 hours

Linear trend

Polarity switch disconnectedmistaken with connection

Negative Polarity Positive Polarity

Conditioning at 175 kV (Negative Polarity)

1

10

100

2/14 2/15 2/16 2/17 2/18 2/19 2/20 2/21

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MinusPlus

Negative Polarity0.4 +/- 0.3 spark per 24 hours

Linear Trend

# 28

# 28

1

10

100

5/12 5/14 5/16 5/18 5/20 5/22 5/24

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Minus Plus

End of measurements

Spark rate at 175 kV: - 0.8 +/- 0.35 sparks per day

1

10

100

6/1 6/3 6/5 6/7 6/9 6/11 6/13 6/15

Tota

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measurement

Spark rate at 175 kV: - 0.25 +/- 0.15 sparks per day

# 6

# 6

Positive polarity

Negative polarity


Spark Rate at 175 kV # 6 (electro-polished) : 0.35 +/- 0.15 per day # 28 (hand-polished) : 0.45 +/- 0.25 per day


1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

120 130 140 150 160 170 180 190

Voltage, kV

Spar

k ra

te p

er y

ear (

365

days

)

#28,178 kV (Neg) #28,178 kV (Pos) #6 178 kV (Neg)#6 178 kV (Pos) #4 180 kV (Neg) #4 180 kV (Pos)#27 180 kV (Neg) #27 180 kV (Pos) #8 180 kV (Neg)#8 180 kV (Pos) #8 150 kV (Neg) #8 150 kV (Pos)#6 150 kV (Neg) #6 150 kV (Pos) Expon. (#8 150 kV (Pos))Expon. (Average)

Conditioning at 180 kV: Spark Rate Summary

For compar ison CERN data were included CERN design:

• 6 cm separation • 4 m long electrodes• 26 cm electrode width• Polished with Scotch - Brite “very

fine 320” to satin finish

Conditioning at higher voltages decreased spark rate (10 kV up spark rate down ~ 10 times)

Expected spark rate at 150 kV for separators conditioned at 180 kV will be less than 1 spark per yearor about 3 order of magnitude less in comparing with separators conditioned just at 150 kV.

1.0E-02

1.0E-01

1.0E+00

1.0E+01

1.0E+02

1.0E+03

1.0E+04

1.0E+05

1.0E+06

1.0E+07

2.0 3.0 4.0 5.0 6.0 7.0 8.0Electric field, MV/m

Spa

rk ra

te p

er y

ear (

365

days

)

#28,178 kV (Neg) #28,178 kV (Pos)#6 178 kV (Neg) #6 178 kV (Pos)#4 180 kV (Neg) #4 180 kV (Pos)#27 180 kV (Neg) #27 180 kV (Pos)#8 180 kV (Neg) #8 180 kV (Pos)Average CERN#8 150 kV (Neg) #8 150 kV (Pos)#6 150 kV (Neg) #6 150 kV (Pos)Expon. (CERN) Expon. (Average)Expon. (#8 150 kV (Pos))

CERN data(no beam)

FNAL data


Summary of Dark Current Measurements

Dark Current Measurements (July 24, 2005)

0.01

0.1

1

10

90 110 130 150 170 190

Voltage, kV

Curre

nt, µ

A

Minus (Neg)

Plus (Neg)

Minus (Pos)

Plus (Pos)

Expon. (Average)

Conditioning up to 180 kVCurrent measurements after

1 week spark rate measurements (July 16 - July24, 2005)

#27


#6 Current Measurements (Feb. 21, 2005)

0.1

1

10

100

140 150 160 170 180 190

Voltage, kV

Curre

nt, µA

Minus (Neg)Plus (Neg)Minus (Pos)Plus (Pos)A

Average

#28

Dark current at 180 kV # 6 and #27 (electro-polished) : ~1.0 µA # 4 and #28 (hand-polished) : ~ 10 - 20 µA (neg. polarity)


High Voltage Electrical Breakdown in Vacuum

It is generally agreed that a vacuum breakdown is a vapor arc, taking place in material evaporated from the electrodes. Evidence is the observation of localized light during breakdown and electrode material transferred across the gap.

Electron field emission mechanism for initiating the breakdownAccording with this model, electrons are assumed to be field emitted from the

tip of microprotrusion at an isolated site on the surface of broad-area cathode.Question: where is the metal vapor produced at the anode or cathode?

Is it enough power to vaporize anode material by field emitted electrons bombarded anode or positive ions produced at the anode lead to rupture of the cathode or that resistive heating on the cathode causes them to melt and ultimately to vaporize. This mechanism dominates at gaps less than 2 mm.

Microparticle or “clump” modelClump of loosely adhesive material is drawn across the gap by the electric field

so as to strike the opposite electrode with enough energy to produce high local temperature in the electrode or clump material with melting and vaporizing.

Pre-operational electrode surface will be characterized by having a finite number of microscopic particles. These will originate from various stages of mechanical polishing, and may be in the form of either impurity particle of polishing material or dust particles. Another source of microparticles are those originated from thermal instabilities at either the cathode or anode “hot” spot. For uniform gaps the breakdown voltage should vary as the square root of the gap spacing. The model is dominated at large gaps.

Ion exchange mechanismThis mechanism is assumed to be initiated by say random positive ion created in

the gap that is than accelerated by the field to generate further negative ions on impact with cathode, which subsequently generate more positive ions on impact with the anode etc. Thus, if the ion multiplication factor > 1, the process will develop in the breakdown mode. It is very sensitive to chemicals contaminations.

Cathode

Anode

e

Primary

Secondary

The breakdown consists of many complicated and complex phenomena with no single process involved.

e


Electrode Conditioning Process

Any conditioning process is to safely quench as many as possible of the sources of breakdown current and “primary” microparticle events.

“Current” conditioningThe applied voltage is increased in small steps such that the prebreakdown current is allowed to

stabilize at each steps before progressing.

Separators were conditioned at current limits about of ~100 µA. Voltages increased step by step of 2 - 10 kV . Voltages applied in following combination:

(-150kV, 0), (0, +150kV) change polarity (0, -150kV), (+150kV, 0)(-150kV, +150kV) change polarity (+150kV, -150kV) (-170kV, +170kV) change polarity (+170kV, -170kV)(-180kV, +180kV) change polarity (+180kV, -180kV)

“Gas” conditioningThe gas normally used for this process is He, Ar, N2, O2, H2 and the phenomenon has been traditionally interpreted in terms of the blunting of metallic emitters by action of high energy gas ion.

In our case a residual gas was used for “gas” conditioning at pressure around 10-6 torr.

“Spark” conditioningThis technique is also known as “spot knocking” is to remove cathode emission sites or spots by arc erosion. It is also efficient in eliminating microdischarge and decreases the incidence of microparticle process.Spark conditioning is effective way to decrease a separator dark current (hot spots).


80

100

120

140

160

16:03 16:06 16:10 16:13 16:16 16:20

0

20

40

60

80

100

16:03 16:06 16:10 16:13 16:16 16:20

0

10

20

30

16:00 16:03 16:06 16:10 16:13 16:16 16:20

16:00 16:03 16:06 16:10 16:13 16:16 16:20

Conditioning effect:Current drop from 40 to 0 µA

~ 15 sparks

MinusPlusVo

ltage

, kV

Cur

rent

, µA

Spa

rks

#P

ress

ure,

torr

10-8

10-9

10-7

10-10

Current Conditioning Effects

0

20

40

60

80

100

120

140

160

180

200

18:20 18:23 18:25 18:28 18:31 18:34 18:37 18:40

Cur

rent

, µA

Volta

ge, k

V

170 kV 169 kV Conditioning at 171 kV

170 kV

Spark

Current discharge

170 kV170 kV

MinusPlus

Positive polarity

0

20

40

60

80

100

120

140

160

180

200

18:20 18:23 18:25 18:28 18:31 18:34 18:37 18:40

Cur

rent

, µA

Volta

ge, k

V

170 kV 169 kV Conditioning at 171 kV

170 kV

Spark

Current discharge

170 kV170 kV

Current dischargeCurrent discharge

170 kV170 kV

MinusPlusMinusPlusMinusMinusPlusPlus

Positive polarity

The disappearance of random charge transients or “microdischarges” from the predreakdown current during its stabilisation is frequently cited as evidence in support of the suppression of microparticle activity in the gap.

Current conditioning at higher voltages is effective way to eliminate microdischarges


Summary of Conditioning Tests

New process for conditioning at higher voltages was well defined and tested.A procedure became much more quickly (hours vs days).

5 beam separators # 4, 6, 8, 27 and 28 were conditioned at 180 kV

A detailed data were obtained on dark current and spark rate dependence vs voltageConditioning at 10 kV higher decrease spark rate roughly 10 times

A measured average spark rate:- at 180 kV 1.0 +/- 0.2 sparks/day- at 175 kV 0.3 +/- 0.1 sparks/day

Estimated spark rate at 150 kV for separators conditioned at 180 kV is ~ 0.6 spark/year.Is it completely meet to technical specs (1 spark/year) requested by AD.

Parameter comparison for hand polish and electropolish separators shows:- no big difference in spark rate at 175-180 kV but for 150 kV spark rate for electropolish

separator is better for few times- a total number of sparks is roughly the same for both hand polish and electropolish

separators that indicates an equal number of primary microparticles - dark current for electropolish separator almost 10 times better in comparing with handpolish

Conditioning separator # 29 with titanium plates is the nextAssembly almost completed (waited for HV feedthrough) New HV power supply prepared for testing


• Prepare and install 5 separators conditioned at 180 kV during next long shutdown in March 2006

3 separators will replace old ones and 2 will be install at new location to improve a beam separation in the arc

• Continue R&D on separators

Complete construction and testing a separator with titanium plates

Higher voltage conditioning up to 200kV (new 250 kV power supplies)

Long term studies of separator performance at 180 kV (deconditioning effect)

Reconditioning of 3 separators removed from Tevatron after shutdown

Keep 4 separators as spare to swap in for installed separators after 2006

Plans in 2005 - 2006


Titanium Plate Production

Titanium, like all metals, is susceptible to certain welding defect and deformations. However, the range of possible defects for titanium is much more than for stainless steel. The surface preparation and adequate gas shielding is crucial for titanium welding.


Technical specs:- straightness 80 mils for 92.6”- flatness 20 mils for 3.0” square

Straightness along separator plate

X

YZ

101.25”

Measurement area (3” x 95”)7.8”

Titanium Plate # 1

2.30

2.40

2.50

2.60

2.70

2.80

0 20 40 60 80 100 120Y, inch

Z,

inch

X = -1.5" X = -1.25" X = -1.0" X = -0.75" X = -0.5" X = -0.25" X = 0.0"X = 0.5" X = 0.25" X = 0.75" X = 1.0" X = 1.25" X = 1.5"

Technical specs

40% of electrode lengths is out of straightness specs

Titanium Plate : Front Face Straightness Measurements

Straightness along separator plate

Titanium Plate # 2

2.3

2.4

2.5

2.6

2.7

2.8

0 20 40 60 80 100 120

Y, inch

Z, in

ch

X = -1.5" X = -1.25" X = -1.0" X = -0.75" X = -0.5" X = -0.25" X = 0.0"X = 0.5" X = 0.25" X = 0.75" X = 1.0" X = 1.25" X = 1.5"

Technical specs

60% of electrode lengths is out of straightness specs

The results of two titanium plate production with using hand weld are not good. A plate deformation and porosity in weld metal is out of technical specs. About 40%-60% of electrode length is out of straightness technical specs. A sag correction is possible but may make damage (crack) electrode.


Electrode Gap Estimation

0.0

1.0

2.0

3.0

4.0

5.0

6.0

0 10 20 30 40 50 60 70 80 90 100 110Y, inch

Gap

, inc

h

Plate #1 Plate #2

Electrode gap profile

2.0" Effective electric field will be less from nominal for about 7.7% due to electrode deformation

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

0 10 20 30 40 50 60 70 80 90 100 110Y, inch

Gap

bet

wee

n pl

ates

,inc

h

Average Gap Estimation

Average gap - 2.153"

Technical specs - 110 mils

This efforts is only R&D, future production should be done with more consideration of titanium manufacturing technology.


Long Term Measurements at 180 kV

0

2

4

6

8

10

12

10/25 10/26 10/27 10/28 10/29 10/30 10/31 11/1

Tota

l num

ber o

f spa

rks

# 1 # 2# 8

Positive Polarity

End of measurements

Spark rate : 0.8 +/- 0.4 sparks/day

0

10

20

30

40

10/11 10/13 10/15 10/17 10/19 10/21 10/23 10/25 10/27

Tota

l num

ber o

f spa

rks

# 1 # 2

Negative Polarity

# 8

end of measurements

Spark rate: 1.7 +/- 0.4 sparks/day

0

2

4

6

8

10

12

10/6 10/7 10/8 10/9 10/10 10/11 10/12 10/13

Tota

l num

ber o

f spa

rks # 1 # 2 # 8

Positive Polarity

End of measurements

Long term separator performance and reliability at 180 kVThere is no any evidence of deconditioning / degradation effect.

y = 0.6939x - 26817

y = 0.1862x - 7192.70

5

10

15

20

25

30

11/1 11/4 11/7 11/10 11/13 11/16 11/19 11/22 11/25 11/28 12/1

Tota

l num

ber o

f spa

rks

# 1 # 2

Linear Linear

# 8Negative Polarity

Long Term Test at 180 kV

End of measurements

Spark rate 0.7 +/- 0.25 sparks/day

tevatron beam separator r@d

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