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Hypernuclear Spectroscopy Experimentsand
Waveform Readout of Germanium Detectors
H. TamuraTohoku Univ.
1. Present Status and Hyperball22. DAY-1 experiment3. Hyperball-J – Readout and DAQ
J-PARC DAQ WS Oct. 14, 2005
PLB 579 (2004) 258
Nucl.Phys.A 754 (2005) 155c
Nucl.Phys.A 754 (2005) 155c
PRC 65 (2002) 034607
PRL 93 (2004) 232501
We want to publish “Table of Hyper-Isotopes”
The bible for nuclear physics
Present status of hypernuclear spectroscopy
1. YN, YY interactions -> Unified picture of B-B interactions, Understand short-range nuclear forcesN spin-dependent forces, force, …
Understand high density nuclear matter (n-star) 2. Impurity effects in nuclear structure Changes of size/shape, symmetry, cluster/shell structure,.. B(E2) -> shrinking effect
3. Medium effects of baryons probed by hyperons B(M1) -> in nucleus
Motivation of Hypernuclear Spectroscopy High-precision (E ~ a few keV) spectroscopy with Ge detectors
At a short distance
Hyperball2
Single Ge (r.e.=60%)
+ BGO(6PMT) x14
Clover Ge (4ch) (r.e. >120%)
+(BGO(12PMT)) x6
Ge: 38 ch, BGO: 156 ch
Peak eff.
~ 2.5% -> 5% at 1 MeV
efficiency x 4
Used at CYRIC (Tohoku) for ordinary nuclear spectroscopy 2005.6--7
Being used at KEK for E566 ( spectroscopy of 12C / 11
B) 2005.9--10
Proposal for DAY1 “Hypernuclear Spectroscopy by (K-,-
)”
Light (survey study)
・ A=4 - ~30 all possible targets 4He, 13
C/ 14N, 20
Ne, 23Na, 27
Al / 28Si, …
(-> Table of hyper-isotopes, N interaction, ...)
Light (detailed study for some important hypernuclei )
・ coin, , polarization -> level scheme, spin-parity
・ DSAM -> B(E2), B(M1)
Hyperfragments ( K-, (-) ), 0.8 GeV/c
・ Light targets (9Be,10B, 11B, 12C) 7He, 8
Li, 8Be, 9
Li, 9B,... (CSB,..)
Medium and heavy p=0.8--1.8, large -> large q
・ E1(p->s) ~4 MeV 89Y, 139
La, 208Pb (p-wave N int.,..)
K1.1+ SPESII
pK= 1.1 and 0.8 GeV/c
12C (parity mixing states), 20
Ne (parity inversion),..9Be (B(E2)), 13
C (B(E2)), 11B (B(M1)), …
Total beam time to be estimated.
non-spin-flip spin-flip
K1.8 + SKS
pK= 1.1 and 1.8 GeV/c or
K- 1.1 + 0.8 GeV/c
Beam and Setup (K1.1 case) Beamline: K1.1 1.2x107 K-/spill at 1.1 GeV/c K/ > 1
Spectrometer: SPESII p/p < 2 MeV (FWHM) ~ 20 msr Hyperball-J
~ 10% at 1 MeV
-
Expected transitions
12C (+,K+) 12C
SKS E~1.5 MeV(FWHM)
Simulation: K1.1, 10g/cm2, 120 hours
(1-b) Light hypernuclei --- example of 12
C
b
a
c
d
g
fe
h ijk
lm
no
p
cb
h
g
k
e j
if
a
l
d
angular correlation
-> spin assignment
coincidence and angular co
rrelations
coincidence spectru
m
-> level scheme
coinc. with a (21- ->11
- )
coinc. with c (12- -> 21
- ) kh
fj
h k
c
12C: simulation
Hyperball-J●(Segmented) Super Clover (350%) x 14 (or normal x 32?) + old normal (60%) x8●Waveform readout●Fast suppression counters (BGO=>PWO)
~ 10% at 1 MeV (x4 of Hyperball) Rate limit ~2x107 particles /s (x5 of Hyperball) => Yield: x20 for single x80 for
PWO
Readout electronics at presentLow-Gain Transistor Reset Preamplifier Reset level ~150 MeV, 6V (gain~40mV/MeV) Fast reset time (~5 s) Resolution
2.2 -> 2.6 keV at 1.33 MeV
Ultra-High-rate Amp Pile up time = integration time (3 s) << normally: shaping time (3-6 s) x10 Fast recovery from reset (~15 s) Resolution 2.2 -> 2.6 keV at 1.33 MeV
pileup resetDead time = 6 s x 50 kHz + 20 s x 10 kHz 30% + 20% = 50%Trigger Rate ~ 500/spill(1 sec) x 2 k words in total
Example of Ge signals at a high rate
Shaper (0.5s) out
Gatedintegrator(GI) out
Preamp inhibit
pile up
reset
beam penetration
baselineshiftshaper
overload
GI dead GI dead
K6 (E566), 3M/1.5s, 15cm from beam
GI bad
Waveform readout method Pileup decomposition and baseline correction by software Goals: single rate:100->500kHz, energy rate 0.5->2.5TeV/s beam limit: K6: 3x106/sec -> K1.1: 1.5x107/sec
Usual waveform method (Digital Signal Processor)
waveform digitizer ~14bit
~40MHz
Preamp. gain 40mV/MeV , Dynamic range 150 MeV-6V Required resolution < 1 keV = 0.04mV -> Digitizer resolution 150,000= 18bit -- impossible
Shaping, PZC, PH-ADC, time stampProcessing speed 200k ev/s
eg. XIA DGF
(We may use this waveform digitizer butwe should make software by ourselves.)
Waveform readout method – our case
Hardware: technically OK, cheaper
Simulation(slow signal) 4s
2s
1s
High energy bg.~50 MeV
Nuclear -ray bg. ~1 MeV
We will take sample data in E566 with existing hardware -> software development -> optimize digitizer parameter
-> Design hardware
slowwaveform digitizer
slow amp
~1s
TFA ~0.1s
>12bit ~40MHz
Multi-hit TDClow-gain
transistor-resetpreamp
CFD
CFD out
Trigger rate and Data rate
Trigger rate (very rough estimate) AGS D6(E930): 200k K-/spill, (K-,-) tirg= 900 trig/spill, x 0.3 by Ge-hit OR
-> J-PARC (K1.1): 9M K-/spill, Hyperball-J x 0.3 -> 0.7 28000 trig/spill (At K1.8, K- intensity at 1.1 GeV/c is one order lower.)
Sever beam-through veto, sever Cerenkov cut to remove K decay x 1/2 PWO suppression in the trigger level x 1/3 PWO total-energy/multiplicity cut (remove 0) x 1/5 ? + Energy deposit tag (enhance hypernuclear events) if necessary Trigger rate < 1000 trig/spill
Data rate Waveform: [13bit x 20MHz x 20s ] x ( 5--20 Ge’s) x 1000 trig/spill ~ 2--8 kw/ev x 1000ev/spill = 4--16MB/spill Others: < 1kw/ev : negligible
Channels Ge: 134 -- 64 ch, waveform (13bit,20MHz) + multihitTDC PWO: 200--300ch, TDC + ADC
1st level 2nd level
2nd level
1st level
2nd level
1st level
Transfer data for Ge without PWO hit
Things to be done Development of waveform analysis software -> How much improvement in high rate performance? -> Optimize digitizer parameters (resolution, sampling)
Shaper + Digitizer module Data transfer should be controlled using PWO info.
Data transfer scheme, Memory modules
“TFA with good BLR (equiv. ORTEC 579) + CFD” module or another digitizer (8bit,~100MHz) for timing info.? Trigger PWO discri. + FPGA module (TUL) ? PWO multiplicity: OK, PWO energy sum: + Linear F/I
Control / diagnostics module (HV control, alarm, Co pulsers,..)