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Energy loss calculations of beam for recoil Si detectors. First what is needed is the minimum beam energy, then reduce by production target energy loss.


Experiment has been scheduled for September 22\(^{nd}\) - 28\(^{th}\). There is the possibility of pre beam production on September 1\(^{st}\) or September 15\(^{15}\).

Primary beam of \(^{34}\)S\(^{8+}\) at 374 MeV (11 MeV/u) to produce \(^{32}\)Si\(^{14+}\) (86.5%) at 10.1(3) MeV/u through a 5 mg/cm\(^2\) Be production target. Degraded \(^{34}\)S through production is 9.7(2) MeV/u.

Primary Beam

374 MeV \(^{34}\)S\(^{8+}\) through 5 mg/cm\(^2\) Be production target leaves 9.7(2) MeV/u \(^{34}\)S with the charge state distribution below.

374 MeV \(^{34}\)S through 5 mg/cm\(^2\) Be production target.
Charge State Fraction (%)
16 73.5
15 25.5
14 1
13 0.01
12 6e-5

Note from Bob Scott on the \(^{34}\)S charge state: From: Scott, Robert H. The peak c.s. for \(^{34}\)S is 8+, you get about 1/3 peak output for 10+, 11+ output is reduced from 10+ to 1/3.

My reply to Matt Hendricks on minimum energy: Acceptable Low-Energy for 34S: 374 MeV (11 MeV/u). Acceptable beam current limit: >250 particle nano-Amps (> 2 euA for 34S8+ I believe).

Response from Richard Pardo: The 2.2 euA of 34S8+ would be 275 pnA. With 60% transmission that would be. 165pnA. Doubling that assuming some source improvement and higher enrichment then gets us to the  325 pnA regime at the gas cell. So we definitely don’t want to strip this to get higher energy. I hope our “G” cryo repairs work and we have a reliable resonator operation for that cryostat by August.

Bob Scott purchased enriched material: 99.5% 34S for $4.8/mg. I have a quote for 400mg at a total of $1944.00 USD.

Secondary Beam

Working in /Research/anl/helios/h0XX/beam_dev with LISE++ output in ray_files. Will generate full outputs for various targets starting with the 374 MeV \(^{34}\)S beam, convert to ROOT files and compare energies and identification plots. Outputs from LISE++ will include those in the figure below.

User cross section is of the s34dp_10.txt type for all recoils. s36_cd2.txt for the \(^{34}\)S beam.

Production using a 5 mg/cm\(^2\) Be target.

Charge state distribution for 374 MeV \(^{34}\)S to \(^{32}\)Si through 5 mg/cm\(^2\) Be target.
Charge State Percent (%)
14 86.5
13 13.3
12 0.2
Lab angle vs. energy relationship for \(^{32}\)Si from 374 MeV \(^{34}\)S beam on 5 mg/cm\(^2\) target.
Lab Angle Energy (MeV/u)
2 10.3
4 10.1
6 9.9

Output file from LISE++.

Energy Loss Information

Ionization Chamber

The ionization chamber will be used for the recoil identification of the reaction. Characteristics of the chamber include:

Si Detectors

Energy ranges into Si for \(^{34}\)S primary and degraded, and \(^{32,33}\)Si recoils.

Beam/Recoil (Energy) Range into Si (\(\mu\)m) Energy loss in 80 \(\mu\)m (MeV) Energy remaining (MeV)
\(^{34}\)S (374 MeV) 150 162 212
\(^{34}\)S (330 MeV) 125 181 149
\(^{32}\)Si (323 MeV) 154 134 189
\(^{33}\)Si (317 MeV) 148 139 178