MEMO CP-A/97
16 June 1999

To:

Distribution

From:

F.E. Chukreev

Subject: About Redundant information in EXFOR
Dr. O. Schwerer sends remarks very often regarding to redundant informationin CAJAD compilations. But the redundant information is harmless and useful.
The redundant information is used for all modes of information transmitting.
We could not understand oral speech without redundant information, because
everybody has some pecularities in his pronounce. The scetch of each letter contains
the redundant information. Without the redundand information we could notunderstand different types and manuscripts. The redundant information is obligatoryfor digital transmitting in electronic nets.
The redundant information is needed for the best understanding of main
information and to conserve the information from random damages or alterations.
Redundant information is used in EXFOR for many cases now. For example,
when you write REACTION as:
Target(beam,product1)product2
Then subfield 3 or 4 is redundant, as if yo know target, beam and product2,
you will not have any hardnesses to calculate product1. But we use the redundant
information to check by checking codes and exclude a misprint.
Second example: When you write nuclei code as: Z-SYM-A, then Z and SYM
is tautology.
Third example: If DETECTOR is (LONGC), then PART-DET is redundant
information because long counter detects neutron only.

The importance of redundant information is not limited by problem ofchecking. The information helps to improve understanding of compilation by users. If
you write:Reaction(25-MN-55(P,N+P)25-MN-54,IND,SIG),

Then IND is redundant information, of course. But it is known, after a searchof Mn-54 on chart of nuclides. The redundant information permits for user to excludea work with additional sources of information. Mn-54 is simple example. Let us see:
REACTION

M(82-PB-0(P,X)29-CU-68-M,,SIG).
G(82-PB-0(P,X)29-CU-68-G,CUM,SIG)

In the case, CU-68-G is daughter of NI-68, but CU-68-M can not be produced
due to radioactive decay NI-68. Any serious user will check first line obligatory. To
check he will be forced to take “Table of Isotopes” or special “Chart of nuclides”. But
if a compiler wrote 29-CU-68-M,IND, then attentive studying of additional sources
will not be needed.
Very many another examples could be added. The examples will include
redundant information for experienced nuclear physicist.
Our activity on nuclear reactions compilation has aim to help for user, to save
his time and trade. Redundant information helps to decide these problems. Until mainusers of EXFOR were experienced nuclear physicists, redundant information was notneeded. Until data exchange used the cards, redundant information was harmful,because the information increased number of cards.
User community is increased now. The community includes scientists, whichhave not special education for nuclear physics. The quantity of transmitted
information is not limited now.
May be, we have not need to struggle against redundant information?

Distribution:
DUNFORD@BNLND2.DNE.BNL.GOV
VML@BNL.GOVNORDBORG@NEA.FR
MARK.KELLETT@OECD.ORG
MANOKHIN@IPPE.RSSI.RU
MAEV@IPPE.RSSI.RU
CBETA@CAJAD.KIAE.SU
DUNAEVA@EXPD.VNIIEF.RU

VARLAMOV@CDFE.NPI.MSU.SU
SCHWERER@IAEAND.IAEA.OR.AT
PRONYAEV@IAEAND.IAEA.OR.AT
CHIBA@EARTH.SGU.AC.JP
KATO@NUCL.SCI.HOKUDAI.AC.JPTENDOW@POSTMAN.RIKEN.GO.JP
YXZHUANG@MIPSA.CIAE.AC.CNCNDC@MIPSA.CIAE.AC.CN
TONG@MIPSA.CIAE.AC.CN
TARKANYI@ATOMKI.HU
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