Focal Plane detectors for Super Heavy Element research 仁科センター森田超重元素研究室の森本です。 まずはじめに世話人の方々、発表の機会を下さいましてありがとうございます。 今回の発表では、私がずいぶん前になりますが開発しました、シンチレーションファイバを用いた位置分解能の良い検出器について 簡単に紹介させて頂きたいと思います。 まず検出器の概要は、このような物です。 RIKEN, Nishina Center Kouji Morimoto

RILAC Facility CSM Acc. Tanks RILAC Acc. Tanks RFQ-Linac 6 years ago, Linear accelerator was upgraded and maximum energy was Increased up to 6 A MEV. Because this maximum energy is enough for production of super heavy element, The GARIS was re-installed here from Ring Cyclotron facility. This is our apparatus GARIS. Energy of the beam from the acc. were monitored by two method. One is a B rho of this 90 bending magnet and the other is TOF of this section. The accuracy of the energy of the beam was pulse minus 0.2 %. RFQ-Linac 18GHz ECR Ion Source

GARIS and GARIS-II Beam from RILAC GARIS GARIS－II Chemistry room

RIKEN GARIS(Gas-filled Recoil Ion Separator) Detection system was installed in this detector chamber. In order to keep vacuum this chamber was sepaleted by myler foil.

Focal Plane Detector system SSD box PSD ions α TOF 6 cm 29.5 cm α This is a focal plane detector installed in the detector chamber. The detector system consists of two TOF detectors and Silicon detector box. Fusion product is implanted in this PSD, mass information obtained in combination with TOF and the implantation energy. An alpha particle accompanied with alpha decay is detected by PSD or PSD with Side detector. The efficiency for decay alpha particle is about 85 %.

209Bi + 70Zn → 278113 + n CN CN a a 1st chain a a a a 2nd chain a a 36.75 MeV TOF 44.61 ns 30.33 mm 36.47 MeV TOF 45.69 ns 30.08 mm 209Bi + 70Zn → 278113 + n 278113 CN 278113 CN a a 1st chain 11.68 MeV (PSD) 344　μs 30.49 mm 11.52 MeV (PSD) 4.93　ms 30.16 mm 23-July-2004 18:55 (JST) 274Rg 274Rg a a 11.15 MeV 6.149+5.003 (PSD+SSD) 9.260 ms 30.40 mm 0.88+10.43=11.31 MeV (PSD+SSD) 34.3 ms 29.61 mm 270Mt 270Mt a a 2nd chain 10.03 MeV 1.136+8.894(PSD+SSD) 7.163 ms 29.79 mm 2.32 MeV (escape) 1.63 s 29.45 mm This figure shows the observed chains. We observed two decay chains with 240 Days of machine times. The decay chains consist of 4 alpha decays and ended by spontaneous fission of Db262. 113 to Mt are new isotopes, and Bh and Db are known isotopes already reported. In order to obtain high degree of internal redundancy, and also we expect to observe the alpha decay of Db262. Because it has about a half of possibility of alpha decay according to the literature. We will continue this experiment. OK, Lets compare the decay cains. The alpha enegies and decay time are like these. Mt of 2nd chain are escaped event. The decay energies of 266Bh have rather wide difference, in this case 700keV. But it is not inconsistent, because … --- 266Bh 266Bh 2-April-2005 2:18 (JST) a a 9.08 MeV (PSD) 2.469 s 30.91 mm 9.77 MeV (PSD) 1.31 s 29.65 mm Wilk et al. Phys. Rev. Lett.85(2000) 9.29±0.1 MeV　0.87 sec 262Db 262Db Table of Isotopes T1/2 34±4 sec S.F. ～33% : α～64% 204.05 MeV(PSD) 40.9 s 30.25 mm 192.32 MeV(PSD) 0.787 s 30.47 mm s.f. s.f.

GARIS + gas-jet system Gas-jet coupled to GARIS as a pre-separator (Promising tool for next-generation SHE chemistry) 248Cm(22Ne,5n)265Sg Preliminary H. Haba, H. Kikunaga, D. Kaji et al., J. Nucl. Radiochem. Sci., 9 27(2008).

Gas-get chamber@GARIS Gas-jet transport system coupled to GARIS Mylar vacuum window (60 mmΦ): 1 μm thickness at 100 kPa Support grids: honeycomb (89%) or circle (72%) structure Chemically inert Teflon chamber: direct injection of chemical reagents Φ60 mm Mylar window (Φ60 mm) Honeycomb grid SUS chamber SHE atoms To chemistry apparatus GARIS Spacer (0, 30, and 60 mm) ~100 Pa He gas (+ aerosol) 100 mm Gas-get chamber@GARIS

GARIS　focal　plane setup

Silicon detector Box PSD TOF SSD box ions 6 cm CANBERRA (PIPS) α TOF 6 cm α CANBERRA　(PIPS) 58x58 mm2 3.75mm　x16 strips, pad resistance 8kΩ Depletion depth 300 μm This is a focal plane detector installed in the detector chamber. The detector system consists of two TOF detectors and Silicon detector box. Fusion product is implanted in this PSD, mass information obtained in combination with TOF and the implantation energy. An alpha particle accompanied with alpha decay is detected by PSD or PSD with Side detector. The efficiency for decay alpha particle is about 85 %. Focal plane detector (Position sensitive　PSD) Side detector

Energy calibration of silicon detector 140Ce + 64Ni evaporation residues 209Bi + 64Ni transfer products to GARIS 64Ni 199At 6.643 MeV p4n evap. 400 196Po 6.520 MeV a4n evap. 209Bi Nat.Ce 212mAt 7.837,7.897 MeV 2pn transfer 300 197Po 6.281 MeV a3n evap. 211Po 7.450 MeV pn transfer 213Rn 8.088 MeV 3pn transfer 212At 7.679 MeV 2pn transfer 213Fr 6.775 MeV 4p transfer Counts/10keV 200 197mPo 6.383 MeV 214mFr 8.546, 8.478 MeV 4pn transfer 211mPo 7.275 MeV pn transfer 198Po 6.182 MeV 214Fr 8.426 MeV 4pn transfer 100 200Po 5.862 MeV 199Po 6.058 MeV system check & energy calibration 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.5 Ea (MeV)

Position resolution Escaped events from PSD Full deposited at PSD Position differences between 271Ds implantation and sequential alpha-decays

Silicon detector box Detection Efficiency for decaying α　particles: 85 % (Geometrical) Dynamic range: high gain 0 - 20 MeV for α decay low gain 0 - 200 MeV for spontaneous fission Pre Amp (Kumagai-san Amp): Cf=2pf (Focal Plane PSD), Cf=3pf (Side ) Shaping time: 2.5 μsec Energy resolution: Focal Plane : 39 keV (FWHM) Focal plane + side : 66 keV Position resolution:　 read out up and down 0.6mm　(10MeV α) 仁科センター森田超重元素研究室の森本です。 まずはじめに世話人の方々、発表の機会を下さいましてありがとうございます。 今回の発表では、私がずいぶん前になりますが開発しました、シンチレーションファイバを用いた位置分解能の良い検出器について 簡単に紹介させて頂きたいと思います。 まず検出器の概要は、このような物です。 For fast decay: 5μsec – Dual ADC (2nd gate) Noise suppression: cooling 5 ℃

ToF detector using thin mylar foil and MCP SSD box PSD ions α TOF 6 cm 29.5 cm α Magnetic shield 磁気シールド 2つの役目：　 　　　TOF測定 入射、崩壊イベントの区別 This is a focal plane detector installed in the detector chamber. The detector system consists of two TOF detectors and Silicon detector box. Fusion product is implanted in this PSD, mass information obtained in combination with TOF and the implantation energy. An alpha particle accompanied with alpha decay is detected by PSD or PSD with Side detector. The efficiency for decay alpha particle is about 85 %.

Time of flight detector Foil: 　0.6 μm mylar + Al 100Å 　　　 + CsI 20 μg/cm2 Wire: Φ12 μm W+Au 2mm pitch Φ80mm Timing resolution: for 241Am α 　530 psec (FWHM) Detection Efficiency:for 241Am α 　99.9 % 　 Transmission efficiency ( two sets of detectors) 94 % (geometrical) Mass resolution A=270 で　約10

Raw data (accumulated for 12 hours) 50 Beam-like particles Total (High gain) 100 40 10 0.3 cps 1 278113 30 10 20 E [MeV] Target-like particles Total [ ROI = 8 - 12MeV ] 20 5 4.2x10-3 cps 10 Counts per 0.01 MeV 8 9 10 11 12 20 40 60 80 100 Anti-coincidence with TOF detectors TOF [ns] 5 Light charged particles 6.3x10-4 cps Now I want to show you raw data. Left side of the figure shows TOF vs E accumrated with 12 hours. The back ground consists of Light-charged particles and Beam like particles and Target like particcles. The compound nucleus clearly separated from background particles. Right side figures are single spectrum. First fig is total spectrum with no gate. Second fig is ROI, 8 to 12 MeV. 3rd fig is after anti-coin with TOF detector. It means decay like events. 4th fig is after +-1mm pos and 60 sec time correlation. There are no back ground events. Mass gate 8 9 10 11 12 30 ER-α correlation (DP = ±1 mm, Dt = 60 s) 20 Counts 278113 5 a4 a3 a2 a1 10 8 9 10 11 12 100 200 300 Energy / MeV Mass

Recent development and Future plans ○　Measurement of short life decay ( < 5μsec ) 　→ measure the pulse shape of pre-amp signal using Flash ADC ○　αｰγ　measurement 　　→　Si + CdTe 　　→　Si + Ge ○　Large area focal plane detectors for GARIS-II →　DSSD　array 　　→ large area ToF detector using large area MCP 仁科センター森田超重元素研究室の森本です。 まずはじめに世話人の方々、発表の機会を下さいましてありがとうございます。 今回の発表では、私がずいぶん前になりますが開発しました、シンチレーションファイバを用いた位置分解能の良い検出器について 簡単に紹介させて頂きたいと思います。 まず検出器の概要は、このような物です。 ○　Improvement for mass measurement →　Ion chamber

PSD TOF SSD box ions Short decay measurement Δｔ E1 E2 6 cm α TOF Δｔ E1 E2 6 cm α Signal processing diagram PreAMP ShapingAmp CAMAC PH-ADC PSD front This is a focal plane detector system installed in the detector chamber. The detector system consists of two TOF detectors and Silicon detector box. Fusion product is implanted in this position sensitive detector PSD, mass information obtained in combination with TOF and the implantation energy. An alpha particle accompanied with alpha decay is detected by PSD or PSD with Side detector. %%The efficiency for decay alpha particle is about 85 %. 16strips Pulse height Computer PreAMP VME PSD rear FlashADC Pulse shape analysis Δｔ E２ E1

Recent development and Future plans ○　Measurement of short life decay ( < 5μsec ) 　→ measure the pulse shape of pre-amp signal using Flash ADC ○　αｰγ　measurement 　　→　Si + CdTe 　　→　Si + Ge ○　Large area focal plane detectors for GARIS-II →　DSSD　array 　　→ large area ToF detector using large area MCP 仁科センター森田超重元素研究室の森本です。 まずはじめに世話人の方々、発表の機会を下さいましてありがとうございます。 今回の発表では、私がずいぶん前になりますが開発しました、シンチレーションファイバを用いた位置分解能の良い検出器について 簡単に紹介させて頂きたいと思います。 まず検出器の概要は、このような物です。 ○　Improvement for mass measurement →　Ion chamber

α-γmeasuremnt 241Am ER ER Si-Ge array Si-CdTe array Si detector BOX 1000 2000 3000 4000 PH(Alpha) [chn] PH(Gamma) [chn] 1200 1300 1400 1500 1600 500 5.44 MeV 5.48 MeV [参考]BGS focal plane 241Am 59.5 keV 26.4 keV Si detector BOX ER TOF detectors FWHM=2.2keV (for 60keV γ-ray) Si-CdTe array Acrorad製CdTe素子 10mmx10mmx1mmt 100 200 300 400 500 2000 4000 6000 8000 TDC [chn] Counts 67 ns decay 10 Si detector BOX ER TOF detectors 10

Recent development and Future plans ○　Measurement of short life decay ( < 5μsec ) 　→ measure the pulse shape of pre-amp signal using Flash ADC ○　αｰγ　measurement 　　→　Si + CdTe 　　→　Si + Ge ○　Large area focal plane detectors for GARIS-II →　DSSD　array 　　→ large area ToF detector using large area MCP 仁科センター森田超重元素研究室の森本です。 まずはじめに世話人の方々、発表の機会を下さいましてありがとうございます。 今回の発表では、私がずいぶん前になりますが開発しました、シンチレーションファイバを用いた位置分解能の良い検出器について 簡単に紹介させて頂きたいと思います。 まず検出器の概要は、このような物です。 ○　Improvement for mass measurement →　Ion chamber

GARIS and GARIS-II Beam from RILAC GARIS GARIS－II Chemistry room

GARIS and GARIS-II GARIS GARIS-II GARIS Beam line GARIS-II Beam line GARIS-II commissioning March-2010

Comparison (GARIS-II vs. World working gas-filled RS) TASCA (HTM) TASCA (SIM) DGFRS BGS RITU GARIS GARIS-II Configuration DQhQv QhDhD QvDQhQv DQhQvD DQhQv DQvQh QvDQhQvD Length [m] 4.0 4.7 4.7 5.8 3.5 3.5 5.1 Bend. Angle [deg] 23 25+45 25 45+10 30 30 30+7 Solid angle [msr] 8.8 45.0 10.0 12.2 13.1 4.3 20.2 Bρ(max) [Tm] 3.10 2.50 2.20 2.16 2.40 2.40 2.43 Dispersion [mm/%] 7.5 20.0 10.0 9.7 9.0 1.0 17.7 Transmission [%] 41* 49-59* ? 40* 60* 36* 75 238U(48Ca,3n)283112 Cross section : 3 pb ** Intensity : 2 puA Target thickness : 500 ug/cm2 Transmission : 75% 3 atoms/day * M. Shaedel, TASCA workshop 2006 (2006). ** Yu. Ts. Oganessian et al., Nucl. Phys. A 734, 195 (2004).

Development of GARIS-II focal plane detector SSD box PSD ions α TOF 6 cm 29.5 cm α Large area silicon detector box DSSD: X: 60strip, Y: 60 strip Large area ToF detector DSSD: 16 strip x 16 strip 70mmφ　→　120mmφ This is a focal plane detector installed in the detector chamber. The detector system consists of two TOF detectors and Silicon detector box. Fusion product is implanted in this PSD, mass information obtained in combination with TOF and the implantation energy. An alpha particle accompanied with alpha decay is detected by PSD or PSD with Side detector. The efficiency for decay alpha particle is about 85 %. Fine pitch (1mm) : low capacitance Front: high gain ( 0 - 20 MeV ) Rear: low gain ( 0 - 200 MeV ) Read out: 60 x 8 = 480ch. 120mm 70mm 60mm DSSD 120mm

Recent development and Future plans ○　Measurement of short life decay ( < 5μsec ) 　→ measure the pulse shape of pre-amp signal using Flash ADC ○　αｰγ　measurement 　　→　Si + CdTe 　　→　Si + Ge ○　Large area focal plane detectors for GARIS-II →　DSSD　array 　　→ large area ToF detector using large area MCP 仁科センター森田超重元素研究室の森本です。 まずはじめに世話人の方々、発表の機会を下さいましてありがとうございます。 今回の発表では、私がずいぶん前になりますが開発しました、シンチレーションファイバを用いた位置分解能の良い検出器について 簡単に紹介させて頂きたいと思います。 まず検出器の概要は、このような物です。 ○　Improvement for mass measurement →　Ion chamber