1. Explanation
General
The database contains the results of calculations with the statistical model (Hauser-Feshbach) code NON-SMOKER for an energy and temperature range which is interesting for astrophysical purposes. Several tables with information can be chosen.Calculations in the statistical model require the input of a number of different nuclear properties:
Although the model is well-established, different calculations vary in the various inputs and treatments of such properties. In the calculations presented here, it was attempted to find descriptions which can be used to predict nuclear properties also for nuclei far off stability for which no experimental data is known. Therefore, it was tried to minimize the direct input of experimental data (although some parametrizations are fit to available nuclear data). Thus, we are interested in descriptions which lead to a low average deviation between predicted and observed properties. Nevertheless, local deviations of higher magnitude can occur.
Details about the inputs used for this statistical model
calculation are given on the same page as the requested table. For an
explanation of the
reference codes and for more details on the calculations and the
NON-SMOKER code, see the reference
section.
Accessing the database
The access form
should be quite
self-explanatory. In the element box, the standard abbreviation of the
element
should be input, as it is used in periodic systems or nuclear charts;
e.g. Ne for Neon or au
for Gold (input is not case sensitive). The massnumber is an integer
with 2 or 3 digits.
Options
The recommended set of options is the default, therefore it should be sufficient in most cases to just enter element and mass number and to select which kind of table and reaction one wants to extract.Theoretical masses:
By default, in the calculations experimental values are used if
available. The setting of the theoretical mass will affect
experimentally unknown masses (separation energies), as well as the
level density for all nuclei.
The FRDM covers the widest mass range, ETFSI values are available only
for A>35, and the ETFSIQ table starts at Cr (Z>23).
Applicability of the model
On some of the tables, warnings may be
given that the
statistical model may not be applicable below a
certain energy
or temperature, although values are given below that limit. The
statistical model assumes that averaged transmission functions can be
used, i.e. averaging over resonances in the contributing energy window
is permitted. At lower excitation energy of the compound nucleus, fewer
resonances will be available and thus there may be a lower
energy/temperature limit for the application of the model.
An estimate of the limiting energy/temperature was derived
in a previous paper
and this is used
here.
It has to be emphasized that very conservative assumptions are used and that the given results may be valid even below the given limit. The warning is merely issued to point out that one should be cautious and aware of the limitations.
There may be another limitation inherent to all statistical
model
calculations which do not explicitly include gamma cascades in the
compound nucleus. Treating the cascades and the particle escape from
the
cascade only approximately may lead to larger errors for reactions with
negative reaction Q values, i.e. for endothermic
reactions. This
is not necessarily the case but, in general, for these cases it is
safer
to calculate the reverse reaction (with positive Q
value) and
compute the desired reaction by applying detailed balance.
Referencing the results
When using results from this database and the linked pages,
credit
should be given to the access page
and the NON-SMOKER
papers.
I would appreciate it if a copy of the work is
sent to me
before
publication, so that misconceptions or misinterpretations of the
results
can be avoided.
Please see also the disclaimer.
Error messages
There are several error messages which can be returned
instead of the
requested table. They should be self-explanatory. Below is a list of
possible messages.
- Database access disabled!
- Access to the database is currently not possible, due to intentional locking. Please try again later.
- Unauthorized Access or Wrong Password
- A wrong username/password combination has been entered (or none at all). Please try again with the correct combination.
- Error in element name
- The element name cannot be recognized. Remember that you have to input the abbreviation of the element, not the charge number. Please try again.
- Error in mass number
- The mass number cannot be converted. Remember that it has to be an integer between 0 and 999. Please try again.
- The results for the requested reaction are currently not publicly available.
- For certain reasons, some of the reaction results may still be restricted. Please try again later. In urgent cases you may send an email message to obtain further information.
- Database currently not accessible...
- The database cannot be opened, either due to intentional locking or because of a crash of the file system. Please try again later.
- Error: Statistical model may not be applicable for this target:
- For very light elements, one has to be very careful in applying the statistical model. Instead of a simple warning message, the access has been disabled for very light nuclei. If you are interested in results for those, please send a request by email.
- No values for this target available
- For the requested reaction, no entry was found. Either you have specified an unbound target outside the neutron- or proton-dripline, or outside the range of calculated elements. (Note, that different mass formula also yield different locations of the driplines).
- Error in target specification
- Either mass number or element name (or both) have not been specified in the query string. This should never happen when the HTML form is used.
- Unknown Table Option
- An unknown option for a table has been specified in the query string. This should never happen when the HTML form is used.
- Error in Database!
- The specified target and reaction was found but the data was not in the proper format. If you encounter this message, please send a message by email, reporting the exact circumstances.
- Error in access control script
- Fatal error. If you encounter this, please send a message by email, reporting the exact circumstances.
Bug reports
If you encounter a failure or an inexplicable result, please first check the explanation of the database and the used methods. Check also the explanation of the error messages. Consult the history section for further details of the current release.In case you still think that there might be a bug in the database or in the returned result, please send a bug report, specifying exactly what you did and where you see the problem.
Thomas Rauscher
2. History
24-Aug-2006
This history list is being discontinued as it is replaced by the forum. Please look there for revisions and other information.20-Aug-2006
Moved to new server. Layout change of web page; database functions should be unaffected.9-Jul-2005 to 11-Jul-2005
Temporarily unavailable due to hardware problem!Problem fixed.