
The ENDF format uses MT numbers to define reaction types,
and some additional MT numbers are used for special sections,
such as the descriptive data, or the resonance parameters.
In the following tables, "z" stands for any of the particles,
i.e., n, p, d, t, He3, a, or photonuclear gamma.
MT 
Reaction 
Description 
Comments 
1 
(n,total) 
Neutron total cross section. Sum of MT=2, 4, 5, 11, 1618,
2226, 2837, 4142, 4445, and 102117. 
Redundant. Undefined for incident charged particles. 
2 
(z,z_{0}) 
Elastic scattering cross section for incident particles. 

3 
(z,nonelastic) 
Nonelastic cross section. Sum of MT=4, 5, 11, 1618, 2226,
2837, 4142, 4445, 102117. 
Redundant. For photon production only. 
4 
(z,n) 
Production of one neutron in the exit channel. Sum of
MT=5091. 
Redundant. For incident neutrons, this is total inelastic
scattering (MT=50 is undefined for neutrons). 
5 
(z,anything) 
Sum of all reactions not given explicitly in another MT
number. This is a partial reaction to be added to
obtain MT=1. 
Each particles can be identified and its multiplicity given
in File 6. Not allowed in Files 4, 5. 
69 

Not allowed in version 6. 
^{9}Be(n,2n) in version 5. 
10 
(z,continuum) 
Total continuum reaction; exclues all discrete reactions. 
Redundant; to be used for derived files only. 
27 
(z,abs) 
Absorption. Sum of MT=18 and MT=102117. 
Redundant. Rarely used. 
101 
(z,disap) 
Disappearance. Sum of MT=102117. 
Redundant. Rarely used. 
NeutronProducing Continuum Reactions
MT 
Reaction 
Description 
Comments 
11 
(z,2nd) 
Production of two neutrons and a deuteron, plus a residual. 

16 
(z,2n) 
Production of two neutrons, plus a residual. 

17 
(z,2n) 
Production of three neutrons, plus a residual. 

18 
(z,fission) 
Total fission. Equal to the sum of MT=19, 20, 21, and 38,
if present. 
Redundant if MT=19 is present. Basic otherwise. 
19 
(z,f) 
Firstchance fission. 

20 
(z,nf) 
Secondchance fission. 

21 
(z,2nf) 
Thirdchance fission. 

22 
(z,na) 
Production of a neutron and alpha particle, plus a residual. 

23 
(z,n3a) 
Production of a neutron and three alpha particles, plus a residual. 

24 
(z,2na) 
Production of two neutrons and an alpha particle, plus a residual. 

25 
(z,3na) 
Production of three neutrons and an alpha particle, plus a residual. 

28 
(z,np) 
Production of a neutron and a proton, plus a residual. 

29 
(z,n2a) 
Production of a neutron and two alpha particles, plus a residual. 

30 
(z,2n2a) 
Production of two neutrons and two alpha particles, plus a residual. 

32 
(z,nd) 
Production of a neutron and a deuteron, plus a residual. 

33 
(z,nt) 
Production of a neutron and a triton, plus a residual. 

34 
(z,n^{3}He) 
Production of a neutron and a ^{3}He particle,
plus a residual. 

35 
(z,nd2a) 
Production of a neutron, a deuteron, and two alpha particles,
plus a residual. 

36 
(z,nt2a) 
Production of a neutron, a triton, and two alpha particles,
plus a residual. 

37 
(z,4n) 
Production of four neutrons, plus a residual. 

38 
(z,3nf) 
Fourthchange fission. 

41 
(z,2np) 
Production of two neutrons and a proton, plus a residual. 

42 
(z,3np) 
Production of three neutrons and a proton, plus a residual. 

44 
(z,n2p) 
Production of a neutron and two protons, plus a residual. 

45 
(z,npa) 
Production of a neutron, a proton, and an alpha particle,
plus a residual. 

NeutronProducing Discrete Reactions
MT 
Reaction 
Description 
Comments 
50 
(z,n_{0}) 
Production of a neutron, leaving the residual nucleus in the
ground state. 
Not allowed for incident neutrons. Use MT=2. 
51 
(z,n_{1}) 
Production of a neutron, leaving the residual nucleus in the
first excited state. 

52 
(z,n_{2}) 
Production of a neutron, leaving the residual nucleus in the
second excited state. 


... 


90 
(z,n_{40}) 
Production of a neutron, leaving the residual nucleus in the
40th excited state. 

91 
(z,n_{c}) 
Production of a neutron in the continuum not included in the
above discrete representation. 

Reactions That Do Not Produce Neutrons
MT 
Reaction 
Description 
Comments 
102 
(z,gamma) 
Radiative capture. 

103 
(z,p) 
Production of a proton, plus a residual. Sum of MT=600649,
if they are present. 
For incident protons, this is inelastic scattering, and MT=600 is
undefined (use MT=2). 
104 
(z,d) 
Production of a deuteron, plus a residual. Sum of MT=650699,
if they are present. 
For incident deuterons, this is inelastic scattering, and MT=650 is
undefined (use MT=2). 
105 
(z,t) 
Production of a triton, plus a residual. Sum of MT=700749,
if they are present. 
For incident tritons, this is inelastic scattering, and MT=700 is
undefined (use MT=2). 
106 
(z,^{3}He) 
Production of a He particles, plus a residual. Sum
of MT=750799, if they are present. 
For incident ^{3}He particles, this is inelastic scattering,
and MT=750 is undefined (use MT=2). 
107 
(z,a) 
Production of an alpha particle, plus a residual. Sum of MT=800849,
if they are present. 
For incident alphas, this is inelastic scattering, and MT=800 is
undefined (use MT=2). 
108 
(z,2a) 
Production of two alphas, plus a residual. 

109 
(z,3a) 
Production of three alphas, plus a residual. 

111 
(z,2p) 
Production of two protons, plus a residual. 

112 
(z,pa) 
Production of a proton and an alpha particle, plus a residual. 

113 
(z,t2a) 
Production of a triton and two alphas, plus a residual. 

114 
(z,d2a) 
Production of a deuteron and two alphas, plus a residual. 

115 
(z,pd) 
Production of a proton and a deuteron, plus a residual. 

116 
(z,pt) 
Production of a proton and a triton, plus a residual. 

117 
(z,da) 
Production of a deuteron and an alpha particle, plus a residual. 

ChargedParticleProducing Discrete Reactions
MT 
Reaction 
Description 
Comments 
600 
(z,p_{0}) 
Production of a proton, leaving the residual nucleus in the
ground state. 
Not allowed for incident protons. Use MT=2. 
601 
(z,p_{1}) 
Production of a proton, leaving the residual nucleus in the
first excited state. 

602 
(z,p_{2}) 
Production of a proton, leaving the residual nucleus in the
second excited state. 


... 


648 
(z,p_{48}) 
Production of a proton, leaving the residual nucleus in the
48th excited state. 

649 
(z,p_{c}) 
Production of a proton in the continuum not included in the
above discrete representation. 

650 
(z,d_{0}) 
Production of a deuteron, leaving the residual nucleus in the
ground state. 
Not allowed for incident deuterons. Use MT=2. 
651 
(z,d_{1}) 
Production of a deuteron, leaving the residual nucleus in the
first excited state. 


... 


698 
(z,d_{48}) 
Production of a deuteron, leaving the residual nucleus in the
48th excited state. 

699 
(z,d_{c}) 
Production of a deuteron in the continuum not included in the
above discrete representation. 

700 
(z,t_{0}) 
Production of a triton, leaving the residual nucleus in the
ground state. 
Not allowed for incident tritons. Use MT=2. 
701 
(z,t_{1}) 
Production of a triton, leaving the residual nucleus in the
first excited state. 


... 


748 
(z,t_{48}) 
Production of a triton, leaving the residual nucleus in the
48th excited state. 

749 
(z,t_{c}) 
Production of a triton in the continuum not included in the
above discrete representation. 

750 
(z,^{3}He_{0}) 
Production of a ^{3}He particle, leaving the residual
nucleus in the ground state. 
Not allowed for incident ^{3}He particles. Use MT=2. 
751 
(z,^{3}He_{1}) 
Production of a ^{3}He particle, leaving the residual
nucleus in the first excited state. 


... 


798 
(z,^{3}He_{48}) 
Production of a ^{3}He particle, leaving the residual
nucleus in the 48th excited state. 

799 
(z,^{3}He_{c}) 
Production of a ^{3}He particle in the continuum not
included in the above discrete representation. 

800 
(z,a_{0}) 
Production of an alpha particle, leaving the residual
nucleus in the ground state. 
Not allowed for incident alphas. Use MT=2. 
801 
(z,a_{1}) 
Production of an alpha particle, leaving the residual
nucleus in the first excited state. 


... 


848 
(z,a_{48}) 
Production of an alpha particle, leaving the residual
nucleus in the 48th excited state. 

849 
(z,a_{c}) 
Production of an alpha particle in the continuum not
included in the above discrete representation. 

