What the Lund/Dubna group wishes to achieve until next annual meeting

• produce two* close-to-final (forward) EGPA clusters

requires CsI(Tl) decided (alternatives?,doping conc?)

from geometry decided (length?, square and rectangular.*)

Milano: readout device decided (APD or PD?)

• put these clusters in correct EXL recoil detector setup (dummy)

requires exact design of ESPA for D-section (foil, thicknesses)

from HV or air (if HV – what wall?)

Milano:

• make complete GEANT4 simulations for these clusters

requires we agree on the input for resolution and efficiency limiting effects

from establish direct cooperation with Orsay group, others?

Milano:

• test the clusters in-beam with both protons and photons

requires from acceptance of beamtime and beamline design

TSL, MAX-lab (preliminarily accepted)

and ACULINNA:

EGPA cluster design

radiation hardness of APD

APD seems to have at least one order of magnitude worse radiation hardness for protons. Neutron damage must also be checked carefully – see report of R. Wolski

Current increase in large area APD with 70 MeV proton bombardment. Current = 5.0 nA before bombardment

3·109 1·1012 p/cm2

HV(semi-vacuum part) and UHV(chamber, Si-support, cables, feedthroughs) aspects

Can the CHICSi parameters be reached with the EXL setup?

Resolution and efficiency limiting effects

elastic and inelastic scattering: up to 30% losses at 200MeV (slide 5) can be cured by summing the energy deposition in (8?) surrounding crystals (slide 6)

sliding trajectories and straggling: these effects call for (truncated) pyrimidal shape and careful simulations (see A.S Fomichev et al., Santiago and Orsay reports)

temperature stability: ΔT = ±0.3º requires cooling? (slide 5)

light collection efficiency and uniformity: doping concentration uniformity must be controlled, polished sides only front and rear – others lapped (slide 5)

energy calibration: individual response functions of type L(E,Z,A) = a1(Z,A)E-a

2(z) to be catalogued by Si +

Si + CsI calibration, pulse shape discrimination to be used (slide 5) and therefore introduced in ASIC (slide 8)

percentage of inelastic interactions in CsI [V. Avdeichikov, A.S. Fomichev, B.Jakobsson, A.M. Rodin and

G.M. Ter-Akopian, Nucl. Instr. Meth. A 501(2003) 505]

longitudinal position dependence of CsI light output

temperature response of CsI detector [V. Avdeichikov, R. Ghetti, P. Golubev, B.Jakobsson and N. Colonna, Nucl. Instr. Meth. A 501(2003) 505]

optimal pulse shape discr. for CsI/PMT device

Simulations

GEANT 4 flow scheme by P. Golubev, M.Karlsson LU and H. Persson UU

single detector readout of protons with energy 0 – 250 MeV passing a Si(0.3 mm) + Si (9 mm) + CsI (200 mm) device

9 detector summation with the same input as for the upper figure

• PICA chip with pulse shape discrimination of E4 channel– Low level spectroscopic signals and noisy fast digital on same chip– Handles process variations– Analogue output– UHV compatible

E1 Preamplifier

E2 Preamplifier

E3 Preamplifier

E4 Preamplifier

Shapers Discriminators

8 bit DAC

Digital block

Analogue multiplexer

Event and multiplicity signal generators

1 mm

8 bit DAC

FEE

Beam-lines available for proton and gamma tests

ACULINNA: Mass separator at JINR, Dubna [A. M. Rodin et al., Nucl. Instr. Meth. B 204 (2003) 114] p, d, t, α etc

MAX-lab: New tagged photon beam-line from MAX electron synchrotron [J-O Adler et al. Nucl. Instr. Meth. A 388 (1996) 17] 10 – 230 MeV photons

TSL/GWC: Cyclotron at The Svedberg Lab., Uppsala [L-O Andersson et al., TSL Progress report 1987-1991 p. 10] p up to 180 MeV, d, t, α