SHMS Heavy Gas Čerenkov Hall C User’s Summer Workshop, August 5, 2008. Garth Huber.

SHMS Heavy Gas ČerenkovSHMS Heavy Gas Čerenkov

Hall C User’s Summer Workshop, August 5, 2008.Hall C User’s Summer Workshop, August 5, 2008.

Garth Huber

22Dr. Garth Huber, Dept. of Physics, Univ. of Regina, Regina, SK S4S0A2, Canada.

IntroductionIntroduction At higher momenta, hadron species cannot be reliably At higher momenta, hadron species cannot be reliably

distinguished by time of flight over the 2.2 m SHMS distinguished by time of flight over the 2.2 m SHMS detector stack baseline.detector stack baseline.

Good PID can be obtained with a series of Čerenkov Good PID can be obtained with a series of Čerenkov detectors:detectors: ee-/-/ππ-- Noble Gas Čerenkov Noble Gas Čerenkov (n-1 < 10(n-1 < 10-4-4)) ππ++//KK++ Heavy Gas Čerenkov Heavy Gas Čerenkov (n-1 ≤ 10(n-1 ≤ 10-3-3)) KK++/p/p Aerogel Čerenkov Aerogel Čerenkov (n-1 ≤ 0.03)(n-1 ≤ 0.03)

Heavy Gas Čerenkov will be the primary means for Heavy Gas Čerenkov will be the primary means for ππ++//KK++ separation above 3.4 GeV/c. separation above 3.4 GeV/c. 1 m long cylinder with 1.6 m diameter, to be operated at 1 m long cylinder with 1.6 m diameter, to be operated at sub- sub-

atmospheric pressure.atmospheric pressure.


Gas recirculation and purification system needed since Gas recirculation and purification system needed since gas pressure will be changed at higher SHMS momenta. gas pressure will be changed at higher SHMS momenta. Maintain sub-atmosphere (0.95 atm) pressure below 7.3 GeV/c.Maintain sub-atmosphere (0.95 atm) pressure below 7.3 GeV/c. Above 7.3 GeV/c, reduce gas pressure to maintain good Above 7.3 GeV/c, reduce gas pressure to maintain good ππ//KK

separation.separation.

Gap between the Gap between the `set’`set’ and and `K’`K’ curves takes curves takes into account the into account the SHMS momentum bite SHMS momentum bite and a possible 0.1 atm and a possible 0.1 atm error in the setting of error in the setting of the gas pressure the gas pressure regulator.regulator.


Focal Plane CoverageFocal Plane Coverage

Non-magnetic stainless steel pressure vessel.Non-magnetic stainless steel pressure vessel.1.6m diameter cylinder.1.6m diameter cylinder.

Titanium entrance and exit windows.Titanium entrance and exit windows.


Optical Ray Tracing StudiesOptical Ray Tracing Studies Co-ordinating design Co-ordinating design

with Donal Day.with Donal Day.

Four thin glass Four thin glass spherical mirrors spherical mirrors (50cmx55cm, (50cmx55cm, radius=175cm) each radius=175cm) each viewed by a 5” PMT.viewed by a 5” PMT.

Asymmetric SHMS Asymmetric SHMS envelope dictates envelope dictates different mirror and different mirror and PMT placements PMT placements for ±for ±δδ..


Projected Projected #p.e.#p.e.

assumingassuming

0.6m effective0.6m effective

radiator pathradiator path

length andlength and

possiblepossible

opticaloptical

misalignment.misalignment.

Projected PerformanceProjected Performance

Useful (7 p.e.) lower momentum limit estimated to be 3.4 GeV/c.Useful (7 p.e.) lower momentum limit estimated to be 3.4 GeV/c.


Updated TimelineUpdated Timeline Design:Design: 2008-2010.2008-2010.

GuideIt studies (CERN optics package).GuideIt studies (CERN optics package). Mechanical design.Mechanical design.

NSERC grant application:NSERC grant application: Fall 2009.Fall 2009. New date dictated by DOE timeline and recent New date dictated by DOE timeline and recent

comments by NSERC re. possible GlueX BCAL support.comments by NSERC re. possible GlueX BCAL support.

Construction:Construction: 2011-2012.2011-2012. Delivery to JLab: Delivery to JLab: Winter, 2013.Winter, 2013. Installation in Hall C: Installation in Hall C: Summer, 2013.Summer, 2013. Detector checkout (no beam):Detector checkout (no beam): Winter, 2014.Winter, 2014.


Radiator Gas UpdateRadiator Gas Update

The heavy gas originally intended for this detector was The heavy gas originally intended for this detector was CC44FF1010.. 3M stopped production of this gas some years ago, although 3M stopped production of this gas some years ago, although

it might still be available from a U.K. supplier (>$300/kg).it might still be available from a U.K. supplier (>$300/kg).

CC44FF88O appears to be the optimal substitute.O appears to be the optimal substitute. Widely used in the semiconductor industry for plasma Widely used in the semiconductor industry for plasma

etching.etching. Easily available from many commercial suppliers.Easily available from many commercial suppliers.

Extensively studied by the BTeV collaboration for use in their Extensively studied by the BTeV collaboration for use in their RICH detector, including beam tests of their prototype.RICH detector, including beam tests of their prototype.

T. Skwarnicki, NIM A T. Skwarnicki, NIM A 553553 (2005) 339-344. (2005) 339-344.

N. Artuso, et al., NIM A N. Artuso, et al., NIM A 558558 (2006) 373-387. (2006) 373-387.


Properties ofProperties ofCC44FF88OO (OctaFluoroTetraHydroFuran)(OctaFluoroTetraHydroFuran)

Gas phase is about 10 times heavier than air (9.19 g/L at 21Gas phase is about 10 times heavier than air (9.19 g/L at 21ooC).C). Boiling point: -5Boiling point: -5ooC.C. Vapor pressure: 1.7 atm @ 21Vapor pressure: 1.7 atm @ 21ooC.C. Stable, non-toxic, non-explosive, non-reactive (except with alkali Stable, non-toxic, non-explosive, non-reactive (except with alkali

halide metals).halide metals). BTeV performed 10 year equivalent exposure tests with a variety of BTeV performed 10 year equivalent exposure tests with a variety of

materials (plastics, mirror material, epoxies, composites, water).materials (plastics, mirror material, epoxies, composites, water).

““No measurable changes seen.”No measurable changes seen.” Can pick-up and transport oils.Can pick-up and transport oils.

need to avoid contact with organic materials.need to avoid contact with organic materials.

Unlike CUnlike C44FF1010, it does not destroy ozone., it does not destroy ozone. Rated as having high global warming potential due to its long Rated as having high global warming potential due to its long

atmospheric lifetime if released.atmospheric lifetime if released. About $100/kg.About $100/kg.


Schematic DesignSchematic Design Non-magnetic stainless Non-magnetic stainless

steel pressure vessel.steel pressure vessel. 1.6m diameter cylinder.1.6m diameter cylinder.

Titanium entrance and Titanium entrance and exit windows.exit windows.

Four high quality thin Four high quality thin glass spherical mirrors glass spherical mirrors (50cmx55cm)(50cmx55cm) Structurally reinforced Structurally reinforced

outside beam envelopeoutside beam envelope.. A gas recirculation and A gas recirculation and

purification system is purification system is needed since the gas needed since the gas pressure will be pressure will be changed frequently for changed frequently for ppSHMSSHMS>7.4 GeV/c.>7.4 GeV/c.


Primary Design ComponentsPrimary Design Components

Protected mirror coatings.Protected mirror coatings. Reference Al coating from Reference Al coating from

Lambda/Ten Optics.Lambda/Ten Optics. >90% reflectivity down to 200 >90% reflectivity down to 200

nm.nm. PMTs view enclosure through PMTs view enclosure through

1cm UV-grade window.1cm UV-grade window. Allows for better isolation of the Allows for better isolation of the

pressurized cavity.pressurized cavity. Photonis flat-face 5” PMTs Photonis flat-face 5” PMTs

mounted flush to window.mounted flush to window. Bases to incorporate voltage Bases to incorporate voltage

boost between photocathode boost between photocathode and first dynode to provide and first dynode to provide optimum focusing of optimum focusing of photoelectrons.photoelectrons.


IntegrationIntegration Will deliver:Will deliver:

Pressure tested Čerenkov enclosure.Pressure tested Čerenkov enclosure. Mounted and aligned mirrors.Mounted and aligned mirrors. PMTs with custom bases.PMTs with custom bases.

Will need to co-ordinate with JLab staff:Will need to co-ordinate with JLab staff: Location of mounting and alignment fixtures.Location of mounting and alignment fixtures. Design, location and fabrication of gas recovery and Design, location and fabrication of gas recovery and

purification system.purification system. Expecting JLab to provide:Expecting JLab to provide:

Readout electronics, HV channels, cables.Readout electronics, HV channels, cables. Mounting and alignment on SHMS detector frame.Mounting and alignment on SHMS detector frame. User interface for remote pressure change whenUser interface for remote pressure change when

ppSHMSSHMS changes. changes. Coordination with U.Virginia (Noble Gas Čerenkov):Coordination with U.Virginia (Noble Gas Čerenkov):

Design, and procurement, where appropriate.Design, and procurement, where appropriate.


FundingFunding

Cost estimate:Cost estimate:

$142k (FY07), Contingency $33k (23%).$142k (FY07), Contingency $33k (23%).

I intend to submit a Research Tools and Instrumentation (RTI) I intend to submit a Research Tools and Instrumentation (RTI) request to NSERC in Fall, 2008.request to NSERC in Fall, 2008. Timing of request is dictated by necessity of CD-3 granting prior Timing of request is dictated by necessity of CD-3 granting prior

to Canadian funding deliberations in early 2009. to Canadian funding deliberations in early 2009.

NSERC grants are announced April 1 each year.NSERC grants are announced April 1 each year.

If the NSERC grant request is successful, it will count as a If the NSERC grant request is successful, it will count as a foreign contribution to the Hall C upgrade and help relieve foreign contribution to the Hall C upgrade and help relieve pressure on the 12 GeV cost book.pressure on the 12 GeV cost book.

SHMS Heavy Gas Čerenkov Hall C User’s Summer Workshop, August 5, 2008. Garth Huber.

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Transcript of SHMS Heavy Gas Čerenkov Hall C User’s Summer Workshop, August 5, 2008. Garth Huber.