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

1.1. Present StatusPresent Status and Hyperball2 and Hyperball2

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

Hyperball (Tohoku/ Kyoto/ KEK, used in 1998-2002)

Side view

BNL E930 setup

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

Hyperball2 at KEK-PS K6 Line (E566)

SKSHyperball2

K6 Q10

2. DAY-1 experiment2. DAY-1 experiment

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

3. Hyperball-J3. Hyperball-J--Readout and DAQ--Readout and DAQ

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,..)