J-PARCJ-PARC でのハイパー核ガンマ線分でのハイパー核ガンマ線分光実験に向けた光実験に向けた Hyperball-JHyperball-J の建設の建設

状況状況

東北大理、 東北大理、 KEKKEK 、 セイコー、 セイコー EG&GEG&G 、 富士電機システ、 富士電機システムズムズ

白鳥昂太郎、 田村裕和、 小野浩、 笠見勝裕、白鳥昂太郎、 田村裕和、 小野浩、 笠見勝裕、小池武志、 竹内孝行、 千賀信幸、 春山富義、 保川幸雄 小池武志、 竹内孝行、 千賀信幸、 春山富義、 保川幸雄 and the Hyperball-J collaborationand the Hyperball-J collaboration

2007 JPS in Hokkaido University

22

ContentsContents

Hyperball-JHyperball-J DesignDesign

Mechanical cooling systemMechanical cooling system Radiation damageRadiation damage R&DR&D

SummarySummary

Hyperball-JHyperball-J

2007 JPS in Hokkaido University

44

E13 experiment at J-PARCE13 experiment at J-PARCSeveral light Several light hypernuclear hypernuclear -ray spectroscopy experiments-ray spectroscopy experiments are planned. are planned.

((44He,He, 77

Li, Li, 1010B, B, 1111

B, B, 1919FF ))

~6%~6% photo peak efficiency @ 1 MeV photo peak efficiency @ 1 MeVfrom geant4 simulation from geant4 simulation

Ge detector×32Ge detector×32 70% relative efficiency70% relative efficiency N-typeN-type Transistor reset type Transistor reset type

LNLN22 cooling cooling

⇒⇒ Mechanical coolingMechanical cooling

Hyperball-J Hyperball-J (half)(half)

2007 JPS in Hokkaido University

55

Hyperball-J designHyperball-J design: “Wall-type” configuration: “Wall-type” configuration

Wall-typeWall-type Large photo-peak efficiencyLarge photo-peak efficiency

Compact detector sizeCompact detector size Low cost of PWO crystalLow cost of PWO crystal FlexibilityFlexibility

Counting rateCounting rate Target and Inner detectorTarget and Inner detector Experimental requirementsExperimental requirements

Hyperball 1stHyperball 1st

2007 JPS in Hokkaido University

66

Hyperball-J designHyperball-J design: “Wall-type” configuration: “Wall-type” configuration

Wall-typeWall-type Large photo-peak efficiencyLarge photo-peak efficiency

Compact detector sizeCompact detector size Low cost of PWO crystalLow cost of PWO crystal FlexibilityFlexibility

Counting rateCounting rate Target and Inner detectorTarget and Inner detector Experimental requirementsExperimental requirements

Hypernuclear Hypernuclear -ray spectroscopy mode-ray spectroscopy mode

BeamBeam

Hyperball-J Hyperball-J (half)(half)

2007 JPS in Hokkaido University

77

Hyperball-J designHyperball-J design: “Wall-type” configuration: “Wall-type” configuration

atom X-ray spectroscopy modeatom X-ray spectroscopy mode

BeamBeam

Wall-typeWall-type Large photo-peak efficiencyLarge photo-peak efficiency

Compact detector sizeCompact detector size Low cost of PWO crystalLow cost of PWO crystal FlexibilityFlexibility

Counting rateCounting rate Target and Inner detectorTarget and Inner detector Experimental requirementsExperimental requirements

Hyperball-J Hyperball-J (half)(half)

2007 JPS in Hokkaido University

88

Hyperball-J design : Frame Hyperball-J design : Frame designdesign

Hyperball-J frameHyperball-J frame

Upper viewUpper view

Driving partsDriving parts

As compact as possibleAs compact as possible

Mechanical coolerMechanical cooler-Suppression for Radiation -Suppression for Radiation damage-damage-

2007 JPS in Hokkaido University

1010

Requirements on Requirements on Hyperball-JHyperball-J

Full model change of Hyperball !!Full model change of Hyperball !! Mechanical coolerMechanical cooler PWO background suppressorPWO background suppressor Waveform readoutWaveform readout

Severe radiation damage Severe radiation damage (~1 month experiment is the limit for KEK)(~1 month experiment is the limit for KEK)

High counting rateHigh counting rateat J-PARCat J-PARC

KEKKEK2.0 MHz 2.0 MHz beam beam

J-PARCJ-PARC~10.0 MHz K beam~10.0 MHz K beam(w/ contamination (w/ contamination

Beam intensityBeam intensity

2007 JPS in Hokkaido University

1111

Radiation damageRadiation damageEnergy resolution gets worse because the electron-hole Energy resolution gets worse because the electron-hole pair is trapped by the damage of Ge crystal.pair is trapped by the damage of Ge crystal. ~10~1099 neutron/cm neutron/cm22 : Visible effects @ KEK : Visible effects @ KEK ~10~101010 neutorn/cm neutorn/cm22 : Terrible effects @ J-PARC : Terrible effects @ J-PARC

The effects can be suppressed by keeping the The effects can be suppressed by keeping the temperature oftemperature of Ge crystal below ~85 K. Ge crystal below ~85 K. ⇒⇒ Mechanical coolingMechanical cooling

Effect of damageEffect of damage

Energy resolutionEnergy resolutionvsvs““Ge crystal Ge crystal Temperature”Temperature”(damaged Ge)(damaged Ge)

E. Hull and R. H. Pehlet al., E. Hull and R. H. Pehlet al., IUCF Ann. Rep. 143, (1993)IUCF Ann. Rep. 143, (1993)

LN2: >90 KLN2: >90 KMechanical cooling : >75 KMechanical cooling : >75 KFWHMFWHM

FWTMFWTM

2007 JPS in Hokkaido University

1212

Sterling cooler

（ Mechanical piston ）

Sterling cooler

（ Mechanical piston ）

圧縮機 蓄冷器 膨脹機放熱機 膨脹機蓄冷器 ﾊﾟﾙｽﾁｭｰﾌﾞ放熱機

ｶﾞｽﾋﾟｽﾄﾝﾊﾞｯﾌｧﾀﾝｸｲﾅｰﾀﾝｽﾁｭｰﾌﾞ

圧縮機

ﾊﾞｯﾌｧﾀﾝｸ

ﾊﾟﾙｽﾁｭｰﾌﾞ

ｲﾅｰﾀﾝｽﾁｭｰﾌﾞ

圧縮機

ｶﾞｽﾋﾟｽﾄﾝ

膨張機

冷却端

ﾋﾟｽﾄﾝ

蓄冷器

RequirementsRequirements Large cooling powerLarge cooling power Low vibrationLow vibration Compact sizeCompact size Long term stabilityLong term stability

⇒ ⇒ Pulse tube refrigeratorPulse tube refrigerator

Conventional Ge detector + RefrigeratorConventional Ge detector + Refrigerator⇒⇒ How to achieve those requirements ?How to achieve those requirements ?

Pulse tube cooler

（ Gas piston ）

Pulse tube cooler

（ Gas piston ）

Mechanical coolerMechanical cooler提供提供富士電機富士電機

2007 JPS in Hokkaido University

1313

圧縮機 蓄冷器 膨脹機放熱機 膨脹機蓄冷器 ﾊﾟﾙｽﾁｭｰﾌﾞ放熱機

ｶﾞｽﾋﾟｽﾄﾝﾊﾞｯﾌｧﾀﾝｸｲﾅｰﾀﾝｽﾁｭｰﾌﾞ

圧縮機

RequirementsRequirements Large cooling powerLarge cooling power Low vibrationLow vibration Compact sizeCompact size Long term stabilityLong term stability

⇒ ⇒ Pulse tube refrigeratorPulse tube refrigerator

Conventional Ge detector + RefrigeratorConventional Ge detector + Refrigerator⇒⇒ How to achieve those requirements ?How to achieve those requirements ?

Pulse tube coller

（ Gas piston ）

Pulse tube coller

（ Gas piston ）

Mechanical coolerMechanical cooler

Sterling cooler

（ Mechanical piston ）

Sterling cooler

（ Mechanical piston ）

Phase shifter(Buffer tank, inertance tube)

Pressure wave generator (sterling)

Regenerator

Pulse Tube

提供提供富士電機富士電機

2007 JPS in Hokkaido University

1414

R&DR&DThree difficultiesThree difficulties1.1. Electric noiseElectric noise

• InsulationInsulation2.2. Microphonic noise by Microphonic noise by

mechanical vibrationmechanical vibration• Flexible jointFlexible joint

3.3. Cooling powerCooling power• Small heat resistanceSmall heat resistance• Water coolingWater cooling

Temperature of Ge crystal : Temperature of Ge crystal : ~76 K~76 KEnergy resolution @ Energy resolution @ 6060Co 1.3 MeV Co 1.3 MeV

: : 2.2 keV (FWHM)2.2 keV (FWHM) (2.1 keV @ cooler power off)(2.1 keV @ cooler power off)

GeGe

Pulse TubePulse TubeCold headCold head

Water coolingWater cooling

Flexible jointFlexible joint

InsulationInsulation

Straight heat rodStraight heat rod

2007 JPS in Hokkaido University

1515

Tohoku University, May 2007Tohoku University, May 2007

Ge detectorGe detector

Mechanical coolerMechanical cooler

DAQ PCDAQ PC

Mechanical coolerMechanical coolerpower supplypower supply

Electric power meterElectric power meter

2007 JPS in Hokkaido University

1616

LNLN22

The first test…The first test…

Mechanical coolerMechanical cooler

keVkeV keVkeV6060Co 1.3 MeVCo 1.3 MeV

-ray energy [keV]-ray energy [keV]-ray energy [keV]-ray energy [keV]

2007 JPS in Hokkaido University

1717-ray energy [keV]-ray energy [keV]

keVkeV

Energy resolution : LNEnergy resolution : LN22

6060CoCo

PulserPulser

2007 JPS in Hokkaido University

1818

Energy resolution : Energy resolution : Mechanical coolerMechanical cooler

keVkeV

6060CoCo

PulserPulser

-ray energy [keV]-ray energy [keV]

2007 JPS in Hokkaido University

1919

In-line mechanical coolerIn-line mechanical coolerWater-cooling Water-cooling （（ regenerator, compressorregenerator, compressor ））

CoolerCooler

GeGe

13 cm13 cm

~110 cm~110 cm

The first Ge detector will be delivered in October.The first Ge detector will be delivered in October.

Final designFinal design

2007 JPS in Hokkaido University

2020

SummarySummary

Hyperball-J Hyperball-J Wall-type configurationWall-type configuration Position-adjustable frame designedPosition-adjustable frame designed

Mechanical coolingMechanical cooling Suppression of severe radiation damage at J-PARCSuppression of severe radiation damage at J-PARC Required Ge crystal temperature (<85 K) and energy Required Ge crystal temperature (<85 K) and energy

resolution (~2 keV) achievedresolution (~2 keV) achieved The first Ge detector delivery in OctoberThe first Ge detector delivery in October