BigRIPS

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Technical Information - Secondary beam intensity expected

 

The LISE++ input file for BigRIPS is ready for use

You can make detailed calculation using the LISE++ code [1] based on the standard configuration and ion optics of BigRIPS and ZeroDegree, and the experimental cross sections that we measured for in-flight fission of 238U (345 A MeV) + Be in 2007 and 2008 [2, 3] in BigRIPS.  We strongly recommend that you use the following LISE++ input files for yield estimation when you submit a proposal of the NP-PAC. We categorized them according to reaction mechanism and ion optics of ZeroDegree. Please choose them according to the production reaction for your experiment and the ion optics of ZeroDegree if you need to use the ZeroDegree beam line. The additional instructions as shown after the list of the LISE++ files would be helpful. Thank you for your cooperation.
(The basic information about the beam line can be seen here)

LISE++ input files:

A) Fragmentation (EPAX2)
A-1) ZDS large acceptance achromatic mode Download (lpp file)
A-2) ZDS high resolution achromatic mode DownLoad (lpp file)
A-3) ZDS medium resolution dispersive mode DownLoad (lpp file)
B) In-flight-fission 238U (345 A MeV)+Be
B-1) ZDS large acceptance achromatic mode DownLoad (lpp file)
B-2) ZDS high resolution achromatic mode DownLoad (lpp file)
B-3) ZDS medium resolution dispersive mode DownLoad (lpp file)
C) In-flight-fission 238U (345 A MeV)+Pb (W)
C-1) ZDS large acceptance achromatic mode DownLoad (lpp file)
C-2) ZDS high resolution achromatic mode DownLoad (lpp file)
C-3) ZDS medium resolution dispersive mode DownLoad (lpp file)
Additional instruction:

(1) How to select the input files

 a) Select a reaction mechanism (A~C)
 b) Select a beam line (1~3)
  If you don't use ZDS, select 1.
  Then click set up in the file and insert Faraday Cup.

   For SHARAQ, insert Faraday Cup 1 after F3.
   For SAMURAI, insert Faraday Cup 3 before F8

(2) Notification in yield estimation using the LISE++ input files

 a) You have to set the beam dump appropriately if the Brho value of the first dipole (D1) is close to that of a primary beam after a production target at the level of the BigRIPS momentum acceptance (+- 3%). Otherwise the calculated yields will overestimate the actual yields by factor of 2 or more. The brief instruction is shown in the following subsection (3).

 b) For fragmentation
  The yield calculation is based on the well-known model, EPAX2. Measured production cross sections of 48Ca (345 A MeV)+Be in BigRIPS are shown in Table 1. Those information may be useful for more correct estimation of fragment yields by scaling calculated cross section with the measured one.

c) For in-flight-fission 238U (345 A MeV)+Be
  Please check the reaction mechanism to be set to Abrasion fission” as following:

  1. Click “options” in menu
  2. Select “reaction mechanism” then you can see the window like below:


click to Large Image

This is just confirmation for unexpected changes of the setting parameters for reaction mechanism in LISE++.
Measured production cross sections of in-flight-fission 238U (345 A MeV)+Be are shown in Table 2.

d) In-flight-fission 238U (345 A MeV)+Pb (W)
Please check the reaction mechanism to be set to "Coulomb fission" + "Abrasion fission (additionally calculate yields for next reactions)"

  1. Click “options” in menu
  2. Select “reaction mechanism” then you can see the window like below:
    You have to perform the selection every time before calculation.


click to Large Image

This is just confirmation for unexpected changes of the setting parameters for reaction mechanism in LISE++.
Measured production cross sections of in-flight-fission 238U (345 A MeV)+Be are shown in Table 3.

(3) How to determine position of the beam dump and input in the LISE++ file.
  (Need the Windows PC in which the LISE++ is installed.)

 Use this excel file. 

  At first determine the position
   a) Input atomic number, mass, and thickness of a target
   b) Input atomic number, mass, and energy of a primary beam
   c) Input Brho of D1
   d) Input position of beam dump in the box of "inside pos" or "outside pos" at up-left  
    of bottom figure.
   e) If the primary is stopped at the beam dump, you can see OK in the box "Hit" below
    the bottom figure.
     If the primary is not stopped at this, you see NG. Then change the position until
    you see OK.
  "Not used" is shown in the box of the beam dump of the side that beam is not
    stopped 

  Then input the position in the LISE++ file.
   a) Click the BeamDump in the LISE++ file.
   b) If inside pos=x mm in the Excel file, input x mm in R slit in a LISE++ file.      
     Else if outside pos.=x mm in the Excel file, input x mm in L slit in a LISE++ file.

References
[1] O.B. Tarasov and D. Bazin, Nucl. Phys. A746(2004)411C
[2] T. Oonishi et al. Journal of the Physical Society of Japan 77 (2008) 083201
[3] T. Oonishi et al. Journal of the Physical Society of Japan 79 (2010) 073201

 

 

Measured cross sections and production yields of 48Ca+Be reaction at 345A MeV since 2008

Neutron rich isotopes from C to S were produced since DayOne experiment in 2008 using the 48Ca+Be reaction at 345A MeV. The measured cross sections and production yields are shown in Table 1 and Fig. 1 together with the calculated values by EPAX2[1]. Systematic uncertainly is estimated within 30 %, which comes from measurement of primary beam intensity.

Table 1: Measured cross sections and yields of 48Ca + Be at 345A MeV. Transmission of the BigRIPS was obtained using LISE++[2]. Error shown in the Table is only statistical one. Systematic error is estimated within 30 %, which comes from uncertainly of primary beam intensity.

IsotopeElement Mass No. Target thickness(mm) Momentum acceptance(%) Yield(pps/pnA) Measured cross section(mb) Error(mb) EPAX2(mb)
C 19 20 ±2 2.17E+02 1.33E-03 5.78E-06 1.89.E-04
20 20 ±3 4.14E+01 1.83E-04 1.45E-06 1.51.E-05
22 20 ±3 5.29E-02 2.19E-07 1.86E-09 6.01.E-08
O 22 15 ±3 6.20E+03 2.42E-02 4.93E-05 8.72.E-03
24 15 ±3 1.48E+01 4.07E-05 2.40E-07 1.12E-04
Ne 21 10 ±0.14 1.97E+05 7.04E+01 2.51E-01 8.25.E+00
23 40 ±2.8 8.00E+05 5.79E+00 5.31E-02 2.71.E+00
26 20 ±3 4.40E+04 1.30E-01 4.68E-04 4.09.E-02
28 15 ±3 9.53E+02 2.55E-03 7.95E-06 8.96.E-04
29 10 ±3 1.84E+01 7.04E-05 1.65E-07 1.06.E-04
  15 ±3 2.00E+01 1.25E-04 1.47E-06 1.06.E-04
30 15 ±3 5.50E+00 1.38E-05 4.84E-08 1.11.E-05
  15 ±3 4.60E+00 9.63E-06 6.13E-08 1.11E-05
31 15 ±3 1.25E-01 2.45E-07 5.57E-09 1.04.E-06
32 20 ±3 3.41E-02 6.89E-08 4.41E-10 8.96.E-08
Mg 25 10 ±3 2.00E+06 7.14E+00 2.79E-02 8.68.E+00
27 10 ±3 2.37E+06 5.84E+00 5.41E-02 5.86.E+00
29 20 ±0.09 6.00E+03 5.17E-01 1.38E-02 7.75.E-01
32 20 ±2.8   9.49E-03 5.28E-05 7.61.E-03
  10 ±0.09 1.90E+02 9.64E-03 1.88E-04 7.61.E-03
33 15 ±0.23 7.30E+01 1.44E-03 2.21E-05 1.21.E-03
34 15 ±3 6.57E+01 1.25E-04 5.50E-07 1.71.E-04
35 15 ±3 2.78E+00 5.12E-06 1.14E-07 2.21.E-05
36 15 ±3 9.00E-01 1.76E-06 4.82E-08 2.62.E-06
37 15 ±3 3.55E-02 6.86E-08 1.85E-09 2.90.E-07
38 15 ±3 1.50E-02 2.93E-08 8.97E-10 3.05.E-08
Al 34 15 ±3 2.60E+03 2.12E-02 6.70E-04 2.24.E-02
41 15 ±3 6.30E-03 1.09E-08 1.42E-09 3.32.E-08
Si 39 15 ±3 1.10E+02 1.70E-04 1.30E-06 4.94.E-04
40 5 ±2.8 2.06E+01 5.97E-05 6.84E-07 8.55.E-05
15   ±3 5.00E+01 1.23E-04 4.24E-07 8.55.E-05
41 15 ±3 3.50E+00 5.60E-06 7.92E-08 1.44.E-05
42 20 ±3 2.45E-01 3.26E-07 2.81E-08 2.25.E-06
15   ±3 2.40E-01 3.88E-07 7.89E-09 2.25.E-06
S 40 15 ±0.09 5.30E+03 1.46E-01 2.15E-04 5.52.E-01
42 15 ±0.09 1.40E+03 4.13E-02 8.26E-05 5.10.E-02
44 15 ±1 3.00E+02 1.91E-03 4.40E-06 2.57.E-03

Fig. 1: Cross sections of C, Ne, Mg, Si and S isotopes of 48Ca + Be at 345A MeV.

[1] K. Summerer and B. Blank, Phys. Rev. C61, 034607 (2000).
[2] O.B. Tarasov and D. Bazin, Nucl. Phys. A746(2004)411c

 

Production cross section for the in-flight-fission 238U (345 A MeV)+Be

Neutron rich isotopes were produced since 2007 using the in-flight-fission 238U (345 A MeV)+Be[1,2]. The measured cross sections from Mg to Sn for several experimental conditions are shown in Table 2 and Fig. 2 together with the calculated values by 3 excitation model in LISE++ [3].  These measured cross sections are input in LISE++ files categorized in reaction mechanism B

References
[1] T. Oonishi et al. Journal of the Physical Society of Japan 77 (2008) 083201
[2] T. Oonishi et al. Journal of the Physical Society of Japan 79 (2010) 073201
[3] O.B. Tarasov and D. Bazin, Nucl. Phys. A746(2004)411C

Download Table2 Cross section table

Table 2  Measured cross sections of the in-flight-fission 238U (345 A MeV)+Be.  Transmission of the BigRIPS was obtained using LISE++. Experimental conditions are as following

Fig2
Fig. 2 Cross sections from Mg to Sn of the in-flight-fission 238U (345 A MeV)+Be

 

Production cross section for the in-flight-fission 238U (345 A MeV)+Pb

Neutron rich isotopes were also produced since 2007 using the in-flight-fission 238U (345 A MeV)+Pb. The cross sections from Cd to Cs, which were measured in experiment of search for new isotopes in 2008[1], are shown in Table 3 and Fig. 3 together with the calculated values by LISE++ [2]. 

References
[1] T. Oonishi et al. Journal of the Physical Society of Japan 79 (2010) 073201
[2] O.B. Tarasov and D. Bazin, Nucl. Phys. A746(2004)411C

Download Table3 Cross section table

Table 3  Measured cross sections of the in-flight-fission 238U (345 A MeV)+Pb.  Transmission of the BigRIPS was obtained using LISE++. The experimental condition is as following

Fig3
Fig. 3 Cross sections from Cd to Cs of the in-flight-fission 238U (345 A MeV)+Be

 

Estimated RI beam intensities (for the first two years)

The estimated intensities of the RI beams available at BigRIPS in the first two years are shown in the figure. The optimum combination of the primary beam and the production target is chosen from 48Ca+Be (350AMeV, 200 pnA),

intensity_day1

86Kr+Be(350AMeV,100 pnA>), 136Xe+Be (350AMeV, 10pnA), 238U+Be and 238U+Pb (350AMeV, 2pnA) to obtain maximum intensities for each isotope. Target thickness is determined to maximize the beam intensity by taking into account the angular- and momentum-acceptances of BigRIPS. As a reaction mechanism, projectile fragmentation is assumed for the beams other than 238U, while both the projectile fragmentation and in-flight fission are taken into account for the 238U beam. To obtain the production cross sections of the projectile fragmentation, and the Coulomb fission reaction (238U+Pb), EPAX2.1[1] and the ABRABLA [2] are employed, respectively. For the nuclear fission (238U+Be), experimental cross sections measured at GSI [3] are used. Therefore, nuclear fission channels are not considered for the nuclei whose cross sections are not available in Ref[3]. Calculations are made for the nuclei which are predicted to be particle bound based on the KUTY mass formula.
Please note that the predictability of EPAX2 is not verified for the production of the nuclei very far from the stability line. For example, the production cross section of 78Ni from the fragmentation of 86Kr on Be target is overestimated by EPAX2 more than two order of magnitude [4].
Numerical results are available in the following tables, in which the optimized target thickness, the expected yield based, the RI beam energy after the production target, and the transmission rate of the fragments are given.

[1] K. Summerer and B. Blank, Phys. Rev. C61, 034607 (2000).
[2] J. Benlliure, A. Grewe, M. de Jong, K.-H. Schmidt, S. Zhdanov , Nucl. Phys. A 628 (1998) 458-478.; private communication with A. Kelic.
[3] Data from K.H. Schmidt Group (GSI)
[4] P.T. Hosmer et al., Phys. Rev. Lett. 94, 112501(2005).

 

Excel format files are available for numerical values.
Fragmentation from 48Ca 350 MeV/u, 200 pnA ca48_frag_350_d0.xls
Fragmentation from 86Kr 350 MeV/u, 100 pnA kr86_frag_350_d0.xls
Fragmentation from 136Xe 350 MeV/u,10 pnA xe136_frag_350_d0.xls
Fragmentation from 238U 350 MeV/u, 2 pnA u238_frag_350_d0.xls
Fission Fragments from 238U 350 MeV/u, 2 pnA u238_frag_350_d0.xls

Estimated RI beam intensities (nominal operating value)

The estimated intensities of RI beams assuming primary beams with 1pµA are shown in the figure. Other conditions used in the calculation are the same as described above.

intensity_max

 





 

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